ISSN 08695938, Stratigraphy and Geological Correlation, 2013, Vol. 21, No. 4, pp. 359–382. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © N.M. Chumakov, M.A. Semikhatov, V.N. Sergeev, 2013, published in Stratigrafiya. Geologicheskaya Korrelyatsiya, 2013, Vol. 21, No. 4, pp. 26–51.
Vendian Reference Section of Southern Middle Siberia
N. M. Chumakov, M. A. Semikhatov, and V. N. Sergeev
Geological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 119017 Russia
email: [email protected]
Received August 15, 2012; in final form October 15, 2012
Abstract—Geological, chemo, and biostratigraphic data indicate that the Vendian section of the Ura uplift
is the most complete one in southern Middle Siberia and contains analogs of main units of the Vendian stra
totype. This section is well known having been investigated by several generations of geologists, well exposed,
and easily accessible; therefore, it is proposed to serve as a regional reference section for Vendian deposits of
the entire southern Middle Siberia. Its description is accompanied by presentation of new biostratigraphic
and radioisotopic data. The section is correlated with other Vendian sections of the Baikal–Patom and some
other world regions.
Keywords: Vendian, microfossils, glacial deposits, Lena River, Ura uplift
DOI: 10.1134/S0869593813040023
INTRODUCTION
In southern Middle Siberia, the most complete
section of Upper Precambrian (Riphean and Vendian)
deposits is exposed in the marginal zone of the
Baikal–Patom Highland. This section comprises six
successive stratigraphic units (from the base upward):
Purpol, Medvezhii, Ballaganakh, Dal’nyaya Taiga,
Zhuya, and “Yudoma” groups, or horizons (Dol’nik,
2000). Until recently, most researchers included only
the Zherba and Tinnaya formations of the Patom
region in the Vendian (Keller et al., 1967; Ivanov et al.,
1995; Pelechaty, 1998); some of them attributed to the
latter also the overlying Nokhtuisk Formation
(Dol’nik, 2000). Many researchers united these for
mations into a larger unit, terming it by analogy with
the Uchur–Maya region as the Yudoma complex or
Yudomian (Opornye…, 1972; Khomentovskii, 2008),
Yudoma Horizon (Dol’nik, 2000), or Yudomian
regional stratigraphic horizon (Stanevich et al., 2006,
2007).
Recently obtained biostratigraphic, chemostrati
graphic, and isotopic geochronological data showed
that the Zherba and Tinnaya formations are correlative
only with the upper part of the Yudoma Group type
section in the Uchur–Maya region (Semikhatov et al.,
2004) and, correspondingly, with the upper layers of
the Vendian section in the East European Platform
and that the two upper groups of the Patom Complex
(Zhuya and Dal’nyaya Taiga) underlying the Zherba
Formation should also be attributed to the Vendian.
Such a conclusion radically changes the age interpre
tation of the Upper Cambrian section in the region
and presentday views on the geological history of the
Baikal–Patom Highland and adjacent segments of the
Siberian Platform. This insistently called for correc
tion of the corresponding regional stratigraphic scales
available for Upper Precambrian deposits of the
Baikal–Patom Highland as well as geological maps
and establishment of the most complete and best dated
Vendian reference section for the region under consid
eration. The section of the Ura uplift which is almost
entirely composed of Vendian rocks was proposed to
serve as such a standard (Chumakov, 2011b).
The transverse Ura uplift complicates the north
eastern margin of the Patom fold arc. It begins near the
Bol’shoi Patom River mouth and extends northward,
crossing the Lena River between mouths of the
Dzherba (Zherba) and Malyi Patom rivers (Fig. 1).
The uplift consists of four wide en echelon arranged
northeastextending anticlinal folds. In the Late Pre
cambrian, the Ura uplift together with adjacent areas
was a constituent of the southern passive margin of the
Siberian Platform. Its Vendian deposits are repre
sented by nonmetamorphosed facies deposited on the
shelf and upper part of the continental slope.
Owing to good exposition, relatively simple tec
tonic structure, and easy accessibility, the Vendian sec
tion of the Ura uplift is well known with its stratigraphy
being progressively upgraded and specified (Fig. 2). At
present, the stratigraphic scale developed for this sec
tion is accepted by almost all researchers, who are
anonymous in admitting the nomenclature of defined
formations and groups. At the same time, the age of its
rocks has remained debatable until now. At the first
stage of investigation of the region, they were attrib
uted to the Upper Proterozoic (Obruchev, 1939; etc.),
Lower Cambrian (Starostina, 1935), or Upper Prot
erozoic–Lower Cambrian (Chumakov, 1956, 1959).
Subsequently, on the basis of finds of microphytolites
and stromatolites (Zhuravleva et al., 1961, 1969;
359
360
CHUMAKOV et al.
116°30′
0
117°00′
10
117°30′ E
20 km
R.
1
Ur a
2
a
Lena
R.
3
b
60°20′
N Bo
l’
4
c
5
m
a to
iP
sho
6
Chapaevo
R.
;
7
8
60°00′
d
Le
na
R
9
.
Fig. 1. The schematic geological map of the Ura uplift. (1–3) Paleozoic–Mesozoic sediments: (1) Jurassic, (2) Ordovician,
(3) Cambrian; (4–7) Vendian sediments: (4) Tinnaya and Zherba formations, (5) Chenchen and Nikol’skoe formations,
(6) Kalancha, Ura, and Barakun formations, (7) Bol’shoi Patom Formation; (8) Riphean sediments: Mariinskaya and Bugarikhta
formations; (9) principal faults. Anticlinal folds: (a) Zherba, (b) Ura, (c) Ulakhan–Iligir, (d) Zhedai.
Dol’nuk, 1982, 2000), the two upper groups of the
Patom Complex (Dal’nyaya Taiga and Zhuya) were
assigned to the Middle and Upper Riphean, respec
tively (Resheniya…, 1963; Keller et al., 1967; Chuma
kov and Semikhatov, 1981; Chumakov, 1993; etc.).
Later, some geologists began correlating the Dal’nyaya
Taiga Group with the Middle and Upper Riphean
(Ivanov et al., 1995; Dol’nik, 2000). On the basis of
historical–geological and, partly, biostratigraphic
data, some researchers attributed the Dal’nyaya Taiga
and Zhuya groups to the upper part of the Upper
Riphean and included them in a new autonomous
Upper Precambrian unit, i.e., Baikalian (Khomen
tovskii et al., 1998; Khomentovskii and Postnikov,
2001; Khomentovskii, 2002). In fact, despite these
disagreements, most researchers shared up to the
beginning of the 21st century the opinion that the
Patom Complex belongs to the Riphean, while the
Vendian includes only the Zherba and Tinnaya forma
tions, which are sandwiched between the Zhuya
Group and Lower Cambrian section.
The revision of widely accepted views on age of
deposits under consideration started in the current
century. First, on the basis of paleotectonic recon
structions and correlation of remote sections, some
researchers suggested that the two upper groups of the
Patom Complex (Dal’nyaya Taiga and Zhuya) belong
to the Vendian (Sovetov, 2002). This opinion was sub
stantiated by chemostratigraphic investigations of
these deposits and their platform analogs (Pokrovskii
et al., 2006), the find of the diverse assemblage of Per
tatatakatype acanthomorphic acritarchs in the Ura
Formation correlated with the upper part of the
Dal’nyaya Taiga Group (Chumakov et al., 2007;
Vorob’eva et al., 2008a; Golubkova et al., 2010), U–Pb
isotopic dating of detrital zircons from metamor
phosed stratigraphic analogs of this formation (Meffre
et al., 2008), and correlation with other Vendian and
Ediacaran sections (Chumakov, 2011).
VENDIAN DEPOSITS OF THE URA UPLIFT
The Upper Precambrian rocks constituting the Ura
uplift are divided into four groups (from the base
upward, Fig. 3): Ballaganakh, Dal’nyaya Taiga,
Zhuya, and Yudoma (Yudoma Horizon). The oldest,
Ballaganakh Group, underlies sequences that may be
attributed to the Vendian. The upper part of the Balla
ganakh Group crops out in the core of the southern
most (Zhedai) anticlinal fold. In the section exposed
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
2013
PALEOZOIC
Ballaga
nakh
Mariinskaya
Dzhem
kukan
Barakun
Valyukhta
Nikol’skoe
Alyanch
Kholych
Zherba
Tinnaya
Yuedei
Ballaga
nakh
Mariinskaya
Dzhem
kukan
Maldoun
Shumikha
Ura
Khalatar
byt
Kalancha
Dolgii
Kulleka
Nikol’skoe
Kholych;
UstPatom
Nokhtuisk
Є Variegated
MACHINO
Є
Sn3
Sn3
Є
Bugarikhta
Mariinskaya
Dzhemkukan
Barakun
Valyukhta
Nikol’skoe
Chenchen
Zherba
Tinnaya
Nokhtuisk
Ivanov et al., 1995
Є 11
Bugarikhta
Mariinskaya
Dzhemkukan
Barakun
Ura
Kalancha
Nikol’skoe
Chenchen
Zherba
Tinnaya
Nokhtuisk
Khomentovskii and Postnikov,
2001
Є1
Bugarikhta
Mariinskaya
Dzhem
kukan
Barakun
Ura
Kalan
cha
Nikol’skoe
Chenchen
Zherba
Tinnaya
Nokhtuisk
Stanevich et al., 2007
VENDIAN
Є 11
Bugarikhta
Mariinskaya
Bol’shoi
patom
Barakun
Ura
Kalan
cha
Nikol’skoe
Chenchen
Zherba
Tinnaya
Nokhtuisk
Reference section
Fig. 2. Stratigraphy of Upper Proterozoic sections in the Ura uplift area according to different authors. (Є) Cambrian; (Sn) Sinian; (R) Riphean; (V) Vendian. Names of eras,
systems, groups, and horizons are denoted in capital letters.
UPPER PRECAMBRIAN (RIPHEAN, SINIAN)
Bobrov, 1964
VENDIAN
UPPER RIPHEAN
YUDOMA
COMPLEX
UPPER
MIDDLE
VENDIAN
R3
R2–3
R2
ZHUYA
DAL’NYAYA TAIGA
BALLA
GANAKH
YUDOMIAN
BAIKALIAN
MAYANIAN
V4
V2–3
V1
YUDOMA
ZHUYA
DAL’NYAYA TAIGA
TREKH
VERSTNYI
ZHUYA
DAL’NYAYA TAIGA
1961, 1969
Valyukhta
ZHUYA
SINIAN (RIPHEAN)
BOL’SHOI BARA VALYUKHTA
PATOM Sn2 KUN Sn2
Sn2
MALYI
PATOM Sn2
Valyukhta
VENDIAN
UPPER RIPHEAN
R2–3
ZHUYA
DAL’NYAYA TAIGA
BALLAGA
NAKH
No. 4
BALLAGA
NAKH
Vol. 21
R3?
STRATIGRAPHY AND GEOLOGICAL CORRELATION
BALLAGA
NAKH
Valyukhta
Zhuravleva et al.,
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
361
362
CHUMAKOV et al.
TREKHVERSTNYI
Є11
–10
–5
0
5
Nokhtuisk
13
14
Tinnaya
15
220–340 m
16
Tirbees
17
Zherba
18
350 m
19
ZHUYA;
Chenchen
400–500 m
0.7086
20
0.7079
0.7080
0.7079
21
Nikol’skoe
150–400 m
22
<647
23
Kalancha
24
400 m
25
Ura
26
0.7077
450–500 m
0.7073
Barakun
DAL’NYAYA TAIGA
upper
250–500 m
middle
200–300 m
lower
200–400 m
cd
<1850
Bol’shoi Patom
900–1100 m
–10
1
–5
0
5
<642 7
2
0.7077 8
3
0.7086 9
4
10
5
11
cd 6
12
BALLAGANAKH
>1200 m
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
in this area, micaceous feldspar–quartz sandstones
(apparent thickness approximately 900 m) are overlain
by finegrained gray limestones alternating with sand
stones (approximately 300 m). By their stratigraphic
position and lithology, the Ballaganakh sandstones
and limestones are correlated with the upper part of
the Bugarikhta Formation and the Mariinskaya For
mation of the Ballaganakh Group in southerly areas,
respectively. According to different estimates, the age
of the Ballaganakh Group varies from Middle Riphean
(Keller et al., 1967; Ivanov et al., 1995; etc.) to Late
Riphean (Khomentovskii and Postnikov, 2001). The
last viewpoint is now supported by high δ13С values
ranging from +5 to +8‰ in carbonates from the
Mariinskaya Formation (Pokrovskii et al., 2006). Such
a high positive δ13С anomaly in the Late Precambrian
is characteristic of the second half of the Late Riphean
(Halverson and ShieldsZhou, 2011).
The Dal’nyaya Taiga Group in the Ura uplift con
sists of four conformably occurring formations (from
the base upward): Bol’shoi Patom, Barakun, Ura, and
Kalancha (Fig. 3).
The Bol’shoi Patom Formation was defined by Sta
rostina (1935) as a unit Сm1а and named in 1941 by
A.A. Predtechenskii in his unpublished work. The
name “Bol’shoi Patom” was repeatedly used for this
unit in different publications (Chumakov, 1959, 1993;
Chumakov and Semikhatov, 1981; etc.). In the unified
stratigraphic regional scale, this formation was incor
rectly termed as the Dzhemkukan Formation, which
violated rules recommended by the Stratigraphic
Code for identification of formation units. Despite
this violation, the name “Dzhemkukan Formation” is
widely used in the literature and in practice. The lower
contact of the Bol’shoi Patom Formation in the Ura
uplift is unobservable. Nevertheless, there are grounds
to believe that it rests conformably upon the Ballaga
nakh Group, since it encloses intercalations of dolo
mitic breccias with rock fragments litholohgically sim
ilar to dolomites of marginal facies from the Mariin
skaya Formation. Erosional contacts marked by such
breccias are also observed at the bases of stratigraphic
and facies analogs of the Bol’shoi Patom Formation
on both the eastern flank (Nichatka Formation,
Bogouyukhta River) and the western flank (Dzhemku
363
kan Formation, Bol’shaya Chuya River) of the Patom
Highland.
Complete sections of the Bol’shoi Patom Forma
tion are confined to the eastern and western limbs of
the southern (Zhedai) anticlinal fold that complicates
the structure of the Ura uplift. These sections are
located at the left bank of the Bol’shoi Patom River 4–
6 and 13–15 km away from its mouth, respectively.
The first of these sections, where the formation is
approximately 1000 m thick, is selected to serve as the
reference one (Chumakov and Krasil’nikov, 1991); in
the second section, the formation thickness is reduced
to 900 m.
The Bol’shoi Patom Formation is largely com
posed of massive and bedded diamictites, gradational
to, less commonly, crossbedded sandstones, and lam
inated to rhythmically bedded siltstones locally with
scattered rock fragments (dropstones) and tillite pel
lets. The upper part of the formation contains isolated
layers and lenses of calcarenites and dolarenites.
Diamictites consist of a dark to locally black silty–
sandy matrix (85–97% of the rock volume) with scat
tered variable rounded pebblesized to large boulder
sized rock fragments. Some of these rock fragments
exhibit subparallel variably sized striation. They are
characterized by relatively uniform lithology being
dominated both quantitatively and volumetrically by
variable gneissose granitoids (gray biotite granites and
granosyenites, 45–65% of fragments) and muscovite
and bimicaceous gneisses (20–35%). They are accom
panied by subordinate dark gray limestones, dolo
mites, quartzites, rare crystalline schists, and meta
morphosed basic rocks (Chumakov and Krasil’nikov,
1991; Chumakov et al., 2010). Some massive diamic
tites demonstrate mostly longitudinal and subordinate
transverse orientation of elongated fragments resem
bling the glacial one (Lungershausen, 1963; Chuma
kov and Krasil’nikov, 1991).
The lower half and upper fourth of the Bol’shoi
Patom Formation are dominated by massive and bed
ded diamictites with subordinate sandstone layers and
lenses. These sediments were likely deposited by gla
ciers that rested on the basin bottom and by floating
shelf glaciers. The middle part of the formation exhib
its frequent alternation of gradational–bedded diam
ictites, sandstones, and shales locally with conglomer
Fig. 3. Composite Vendian section of the Ura uplift.
(1) Faunal remains of the Tommotian Aldanocyathus sunnaginicus Zone of the Lower Cambrian; (2) faunal remains of the Nem
akit–Daldynian Purella antiqua Zone of the Upper Vendian; (3) faunal remains of the Namakit–Daldynian Anabarites trisulcatus
Zone of the Upper Vendian; (4) Ura acritarchs assemblage; (5) impressions of Beltanelloides sorichevae; (6) cap dolomite;
(7) U–Pb age of detrital zircons; (8, 9) 87Sr/86Sr ratios in carbonate rocks: (8) according to (Pokrovskii et al., 2006), (9) accord
ing to (Melezhik et al., 2009); (10–12) variations of δ13С (‰) in carbonate rocks: (10) according to (Pokrovskii et al., 2006,
(11) according to (Pelechaty, 1998), (12) according to (Khomentovskii et al., 2004); (13) diamictite; (14) diamictite with carbon
ate rock fragments; (15) conglomerate; (16) carbonate breccia; (17) sandstone; (18) quartzitelike sandstone; (19) marlstone;
(20) siltstone and mudstone; (21) limestone; (22) horizon of anthraconite limestone; (23) dolomite; (24) sandy limestone and
1
dolomite; (25) oolitic limestone; (26) stromatolitic limestone and dolomite. ( ~
C 1 ) Tommotian Stage of the Lower Cambrian.
Names of groups are given in capital letters.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
364
CHUMAKOV et al.
ates, which fill erosional valleys. These sediments
characterize underwater fans of glacial rivers. The
lithology of rock fragments and the crossbedding pat
terns in sandstones suggest that detrital material was
transported to the Bol’shoi Patom basin from the Sibe
rian Platform mainly owing to erosion of crystalline
rocks of the basement and partly the sedimentary Bal
laganakh Formation (Chumakov and Krasil’nikov,
1991). U–Pb age estimates obtained for detrital zircon
from sandstones alternating with massive diamictites
confirm this inference (Chumakov et al., 2011b). On
the curve of the relative age probability, most of these
zircons fall into the Archean (from 3200 to 2500 Ma
with the maximum at 2700 Ma) and Early Proterozoic
(from 2400 to 1850 Ma with distinct maxima at 1850
and 1950 Ma) intervals.
The prevalence of diamictites (including their mas
sive varieties with glacial orientation of rock fragments
and bedded varieties) and the presence of erratic frag
ments of crystalline rocks, dropstones, tillite pellets,
striated and grooved boulders—all these features indi
cate glacial and glaciomarine origin of rocks constitut
ing the Bol’shoi Patom Formation. Typical cap dolo
mites resting upon the Bol’shoi Patom Formation sup
port this conclusion. The glacial genesis of the
formation is also confirmed by its reliable correlation
with glacial sediments of the Nichatka Formation,
which includes typical tillites and lacustrine and flu
vioglacial sediments, in addition to glaciomarine
facies (Chumakov, 1993, 2011a). The carbonate con
stituent of calcareous sandstones occurring among
diamictites in the upper part of the Bol’shoi Patom
Formation is characterized by δ13С values ranging
from –5.9 to –8.8‰ (VPDB), while carbonate boul
ders, pebbles, and dolarenites from diamictites (nine
samples) demonstrate significant scatter of δ13С values
varying from –6.5 and –5.1 to +5‰ with prevalence
of small negative and positive values: from– 0.9 to
+2.2‰ (Pokrovskii et al., 2010). The presence of
three groups of carbonate rock fragments with sharply
different δ13С values undoubtedly suggests different
provenances during the Bol’shoi Patom glaciation. For
example, the presence of rock fragments with consid
erable positive δ13С values indicates erosion of the
Mariinskaya Formation. The measurement of the
87Sr/86Sr ratios in a single boulder of dolomitic lime
stone from the Bol’shoi Patom Formation yielded the
value of 0.70747 with the δ13С value being equal to –
5.1‰ (Pokrovskii et al., 2010). It is conceivable that
these isotopic ratios indicate sediment reworking dur
ing deposition of the formation. In two beds of detrital
dolomites (dolorudites and dolarenites) occurring in
the upper part of the Bol’shoi Patom Formation, the
values of the 87Sr/86Sr ratio appeared to be very high,
being 0.71451 and 0.71480, respectively, which is very
close to the 87Sr/86Sr ratios typical of many cap dolo
mites, including varieties overlying this stratigraphic
unit (Pokrovskii et al., 2010). Such a similarity likely
implies that, during deglaciation, which was charac
terized by oscillations, nearglacier basins accumu
lated intermittently detrital dolomites, the first pre
cursors of distal cap dolomites.
The Barakun Formation in sections of the Ura
uplift consists of alternating members largely com
posed of dark limestones and black shales. Some lime
stone members include shale intercalations, while
shale members are usually intercalated by limestones.
Extended outcrops of the formation are relatively rare
and represented by limestones. In the Ura uplift, the
Barakun Formation is divisible into three subforma
tions: lower and upper mostly limy and middle mainly
shaly (Chumakov, 1959; Ivanov et al., 1995; Kokoulin,
1998; etc.). Bobrov (1964) proposed to consider these
subformations as autonomous formations (Fig. 2),
although this suggestion was disfavored.
The lower Barakun Subformation. The lower con
tact of the Barakun Formation is observable in the
western limb of the Ura anticline on the right side of
the Ura River downstream of the Voron Rapids. In this
area, the upper layer of bedded diamictites of the
Bol’shoi Patom Formation is overlain by inequigranu
lar sandstones 0.5–0.8 m thick with rare pebbles,
which grade upward along the section into a thin layer
of silty finegrained poorly consolidated sandstones
(Chumakov and Krasil’nikov; Chumakov et al., 2011).
They in turn give way to a peculiar member of dark
gray laminated and rhyrthmically bedded calcareous
dolomites with the apparent thickness of approxi
mately 6 m. Lamination of these rocks is determined
by alternation of dark and lighter micritic and pelletic
laminae from fractions of a millimeter to 1 mm thick.
Dolomites include rare small quartz and feldspar clasts
and an admixture of clay minerals (insoluble residue
varies from 7 to 13%). Weathered surfaces of dolomites
are usually light yellow. Regular lamination of dolo
mites is locally complicated by small (up to 0.5 m
across) asymmetrical intrastratal anticlinal folds with
detachments in hinges (Fig. 4). In the literature, such
textures are called teepees. The texture and fine rhyth
mical lamination of dolomites, negative isotopic car
bon composition (δ13С varies from –4.2 to –3.5‰),
and very high 87Sr/86Sr ratios amounting to 0.71597–
0.71690 (Pokrovskii et al., 2006, 2010) are typical of
cap dolomites, which crown many Neoproterozoic
glacial formations (Chumakov, 1978, 1992; Fairchild
and Hambrey, 1984; Pokrovskii et al., 2006, 2010;
etc.). Small outcrops and debris of cap dolomites at
the base of the lower Barakun Subformation are also
recorded in the eastern limb of the Ura anticline on
the left side of the Ura River 1 km downstream of the
Ulakhan Iligir River and along the right bank of the
Lena River in the northeastern limb of a pericline of
the Zhedai anticline 3.5 km downstream of the
Chapaevo Settlement, where their apparent thickness
is approximately 10–15 m.
The wide distribution of cap dolomites and their
genesis have received much attention for a long time
(Fairchild and Kennedy, 2007 and references therein).
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
365
5 сm
Fig. 4. Cap dolomite with teepee textures in the basal layer of the Barakun Formation. Right bank of the Ura River 0.5 km down
stream of the Voron Rapids (photo by V.A. Melezhik).
Judging from several features, cap dolomites were
deposited in periglacial basins during postglacial
transgressions under intense continental drainage
caused by deglaciation. The detailed geochemical
characterization of the Barakun cap dolomite is avail
able in (Pokrovskii et al., 2010).
In the Ura River area, the cap dolomites of the
lower Barakun Subformation are replaced upward
along the section by dark clayey limestones and calcar
eous shales (several tens of meters thick) overlain in
turn by dark bedded finegrained locally pyritized cal
careous polymictic sandstones approximately 100–
120 m thick with thin siltstone and mudstone mem
bers. One of these members 150 m above the base of
the formation outcropping on the left side of the Ura
River 670 m downstream of the Ulakhan Iligir River
mouth yielded impressions of Vendian fossils Beltanel
loides sorichevae (Leonov and Rud’ko, 2012). The
overlying largely carbonate part of the lower subforma
tion of the Barakun Formation crops out on the left
side of the Bol’shoi Patom River 4 km downstream of
the Dzherbedyanka River mouth. The subformation is
mostly composed of dark gray to black finegrained
dolomitic laminated and platy limestones, some of
STRATIGRAPHY AND GEOLOGICAL CORRELATION
which are distinctly detrital in origin. They are fre
quently represented also by algal, microphytolitic, and
oolitic varieties with siliceous concretions. Some
limestone layers exhibit underwater slumping struc
tures accompanied by carbonate breccias. The share of
shales, which form in the lower part of the formation
rare thin intercalations, increases upward along the
section to constitute a uniform member up to 20 m
thick at its top. The total thickness of the lower subfor
mation of the Barakun Formation is estimated to
range from 200 m (Chumakov, 1959) to 400 m
(Bobrov, 1964).
During deposition of the lower subformation of the
Barakun Formation, the provenances were evidently
slightly different as compared with their counterparts
in the Bol’shoi Patom time: mainly Archean shields
were eroded. This is evident from U–Pb age of detrital
zircons from sandstones of the lower Barakun Subfor
1
mation in the Ura River section. On curves of the rel
ative age probability compiled for Barakun detrital zir
1 The data were obtained by I.N. Kapitonov and analysts from the
ICP–MS group of the AllRussian Institute of Geology
(VSEGEI, St. Petersburg.
Vol. 21
No. 4
2013
366
CHUMAKOV et al.
cons, its maxima are dated at 2900 and 2500 Ma, while
the number of zircons with Early Proterozoic ages
appeared to be insignificant as compared with the
Bol’shoi Patom Formation (Chumakov et al., 2011b).
Zircons from the lower subformation of the Barakun
Formation with discordance exceeding 10% form a
trend, which indicates, in the opinion of I.N. Kapi
tonov, that some zircon grains were likely influenced
650 ± 300 Ma ago by an event that disturbed their
U⎯Pb isotopic system. This could have been strati
form intrusion of gabbro–dolerites near the contact
between the Bol’shoi Patom and Barakun formations.
The middle Barakun Subformation is largely com
posed of black siltstones and mudstone shales with
rare thin intercalations and occasional members of
coarse to finegrained black thinbedded and platy
limestones with beds of black dolomitic limestones,
lenses of limestone breccias, and thin breccia hori
zons. These rocks include subordinate rare beds of
black calcareous finegrained sandstones. The upper
170 m of the subformation are relatively well exposed
on the right side of the Bol’soi Patom River in its
mouth area opposite Khatyng Aryy Island. The sub
formation thickness is estimated to range from 200–
250 m (Kokoulin, 1998) to 300 m (Chumakov, 1959).
The upper Barakun Subformation. In the Khatyng
Aryy Island area, shales of the middle Barakun Sub
formation are overlain by a thick (approximately
400 m) sequence of black limestones of the upper Bar
akun Subformation. These rocks are represented by
platy thinbedded finegrained varieties with interca
lations of clayey and dolomitic limestones and
coarsegrained limestones intercalated by thin lami
nae of calcareous shales. The remarkable feature of
the subformation is intrastratal limestone conglomer
ates and 10 to 20mthick lenses of brecciaconglom
erate with underwater slumping structures. They con
sist of subangular deformed fragments of carbonate
rocks and subrounded olistoliths of limestones and
dolomites cemented by calcareous shales. The thick
ness of the subformation is estimated to be 250 m
(Kokoulin, 1998) or 500 m (Chumakov, 1959).
It is difficult to determine the total thickness of the
Barakun Formation in the Ura uplift because of its
poor exposition, which explains discrepancies in esti
mates obtained by different researchers. In our opin
ion, the most realistic estimate is 1100–1200 m.
The δ13C and 87Sr/86Sr values determined in the
Ura uplift for the Mariinskaya, Bol’shoi Patom, and
Barakun formations and overlying carbonates of the
Dal’nyaya Taiga and Zhuya groups (Pokrovskii et al.,
2006, 2010) serve as a basis for the chemostratigraphic
characteristic of the proposed Vendian reference sec
tion and are of significance for determining the age of
these rocks and regional correlations. As was men
tioned, the δ13C value in basal cap dolomites of the
lower Barakun Subformation varies from –4.2 to
⎯3.5‰; in overlying limestones, this parameter
decreases to zero values. Higher in the section, the
δ13C value rapidly increases to reach +8.1‰ in the
middle part of the lower Barakun Subformation.
Higher, almost to the top of the Barakun Formation,
the δ13C value remains uniformly high: δ13Caver =
6.5 ± 1‰ (n = 13). According to five measurements,
the minimum 87Sr/86Sr value in the Barakun Forma
tion is 0.70727 (Pokrovskii et al., 2006) and that in the
lower part of the formation (one measurement) is
2
0.70776 (Pokrovskii et al., 2010).
The Ura Formation rests conformably upon the
Baraklun Formation and is largely composed of silt
stones and mudstones with subordinate intercalations
and members of dolomites and limestones (Kolosov,
1975; Kokoulin, 1998). Its most complete section is
documented at the southern pericline of the Zherba
anticline in the lower reaches of the left Lena River
tributary along the Ulakhan Muostakh Creek, where it
was defined as the lower Valyukhta Subformation by
some researchers (Zamaraev, 1984). In this area, the
basal part of the Ura Formation is represented by a
300mthick sequence of siltstones and mudstones
with intercalations of black to dark gray dolomites
overlain by breccias of carbonate rocks 200 m thick. A
slightly different section is observed in the Ura River
basin. Its lower part (approximately 70 m) exposed on
the right side of the Ura River 2.5 km downstream of
the waterfall (23 km from the Ura River mouth) is rep
resented by gray and black siltstones and calcareous
shales frequently (fractions of a meter) alternating
with limestones and their clayey varieties. Limestones
are frequently characterized by detrital texture, oolite
fragments, and underwater slumping deformations.
This part of the Ura Formation is underlain by a 10 to
12mthick bed of carbonate breccia conglomerate
belonging most likely to the Barakun Formation. The
upper contact of the Ura Formation is observable on
δ13C and 87Sr/86Sr values cited in this work were obtained
for Vendian sequences of the Ura uplift by analyzing carbonate
phases of samples without accounting for geochemical preserva
tion criteria of C and S isotopic systems in carbonate rocks
(Mn/Sr and Fe/Sr ratios and δ18O value). The main agents
responsible for distortion of systems in carbonates are repre
sented by meteoric water and lowtemperature epigenetic fluids,
which are enriched, as compared with seawater, in Mn, Fe, and
12C originating from associated siliciclastic sequences and char
acterized also by an elevated 87Sr/86Sr value, decreased Sr con
centration, and reduced δ13C and δ18O values (Brand and
Veizer, 1980; Derry et al., 1992; Denison et al., 1994; Knoll et
al., 1995; Gorokhov et al., 1995; Kuznetsov et al., 2006, 2012).
It should be emphasized that the curves of changes in the δ13C
value obtained by B.G. Pokrovskii and colleagues are similar in
their amplitude variations and character of changes to curves
available for global standard Upper Precambrian sections: in the
Doushantuo and Dengying formations of South China (Zhou et
al., 2007; Zhou and Xiao, 2007) and in eastern and northern
Oman (Brasier et al., 2000; Leather et al., 2002; Le Guerroue,
2010). Moreover, the 87Sr/86Sr values obtained by Pokrovskii
and colleagues for the Zhuya Group correspond quantitatively
to ratios determined for the same rocks using the abovemen
tioned geochemical preservation criteria of isotopic systems
(Gorokhov et al., 1995; Pelechaty, 1998; Melezhik et al., 2009).
2 The
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
the right side of the Ura River and its valley slope 3.0–
3.3 km from the mouth. The upper part of the Ura
Formation (approximately 30– 35 m thick) is com
posed of peculiar gray to greenish gray siltstones inter
calated by subordinate thin (fractions of a meter) gray
and black limestones with inclusions of coarsegrained
varieties and thinbedded siltstones (Fig. 5). South of
the Ura uplift, the Ura Formation is replaced by dark
gray to black shales, which are attributed to the lower
part of the Valyukhta Formation. The total thickness
of the Ura Formation in these sections is 400–500 m
(Bobrov, 1964, 1979; Zamaraev, 1984; Kokoulin,
1998).
In the section located on the right side of the Ura
River 3 km from its mouth, thinbedded siltstones
occurring 30–35 m below the top of the Ura Forma
tion yielded a diverse Ediacaran assemblage of acanth
omorphic palynoflora or assemblage of Pertatataka
type acanthomorphic acritarchs found at four levels
(Faizullin, 1998; Nagovitsin et al., 2004; Chumakov et
al., 2007; Vorob’eva et al., 2008a; Golubkova et al.,
2010; Sergeev et al., 2011; Moczydlowska and Nago
vitsin, 2012). The analysis of all the mentioned works
reveals the following valid taxa of capriciously shaped
acanthomorphic, sphaeromorphic, and netromorphic
acritarchs and presumable remains of cyanobacteria in
the Ura microbiota: Ancorosphaeridium magnum Ser
geev et al., 2011; A. minor Sergeev et al., 2011;
A. robustum Moczydlowska et Nagovitsin, 2012;
Appendisphaera tenuis Moczydlowska et al., 1993;
A. tabifica Moczydlowska et al., 1993; Archaeot
enuisphaeridium cf. fimbriatum Grey, 2005; Asseserium
fusulentum Moczydlowska et Nagovitsin, 2012;
A. piramidalis Moczydlowska et Nagovitsin, 2012;
Cavaspina acuminata (Kolosova, 1991); C. basiconica
Moczydlowska et al., 1993; C. uria (Nagovitsin et Fai
zullin, 2004); Ceratosphaeridium cf. glaberosum Grey,
2005; Densisphaera arista Moczydlowska et Nago
vitsin, 2012; D. fistulosa Moczydlowska et Nagovitsin,
2012; Eotylotopalla cf. delicata Yin, 1987; E. strobilata
(Faizullin, 1998); Knollisphaeridium maximum (Yin,
1987); Labruscasphaeridium sp., Multifronsphaeridium
ramosum Moczydlowska et Nagovitsin, 2012; Schizo
fusa zangwenlongii Grey, 2005; ?Sinosphaera rupina
Zhang et al., 1998; Tanarium anozos Willman, 2008;
T. conoideum Kolosova, 1991; T. digitiformum (Nago
vitsin et Faizullin, 2004); T. muntense Grey, 2005;
T. tuberosum Moczydlowska et al., 1993; Urashaera
capitalis Moczydlowska et Nagovitsin, 2012; Variom
Fig. 5. Section of the upper part of the Ura Formation and
lower part of the Kalancha Formation. Right bank of the
Ura River 3 km upstream of the mouth (according to
M.V. Leonov, S.V. Rud’ko, and N.M. Chumakov).
(1) Gray limestone; (2) black anthraconitic limestone;
(3) siltstone and mudstone; (4) underwater slumping tex
tures; (5) casts of erosion scours; (6) smallscale lenticular
bedding; (7) stratiform stromatolites; (8) coneincone
textures; (9) finds of acritarchs of the Ura assemblage.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
m
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Vol. 21
367
Kalancha
Formation
1
2
Ura
Formation
3
4
5
6
7
8
9
No. 4
2013
368
CHUMAKOV et al.
argosphaeridium floridum Moczydlowska et Nago
vitsin, 2012; Leiosphaeridia spp.; Gen et sp. indet.;
Segmentothallus aff. S. asperus Hermann, 1989; Rug
osoopsis tenuis Timofeev et Hermann, 1979; Bul
latosphaera velata Vorob’eva et al., 2009; Aimia aff.
A. gigantica Hermann; Ceratophyton sp.; Polytry
choides lineatus Hermann, 1974; Digitus fulvus Pjatile
tov, 1980; Obruchevella cf. Cucumiforma sp.; Siphono
phycus spp.; unnamed filamentous microfossils;
unnamed forms 1–5.
This list includes also species from (Moczydlowska
and Nagovitsin, 2012), where these authors formally
revised several taxa previously known from the Ura
Formation and described a group of new genera and
species, which may be considered as valid until the
next revision of the Ura microbiota. At the same time,
Moczydlowska and Nagovitsin (2012) regarded, with
out any explanations, some taxa described in (Sergeev
et al., 2011) such as Bullatosphaera velata and Animia
aff. A. gigantica as taxonomic artifacts and identified in
the Ura Formation, also without any grounds, Miro
edichia lobata and Trachyhystrichosphaera aimica
(Nagoitsin et al., 2004), which were rejected for the
Ura biota in (Sergeev et al., 2011) in accordance with
all formal principles of the paleontological nomencla
ture. Therefore, references to the presence of Miroedi
chia and Trachyhystrichosphaera in the Ura Forma
tion cannot be accepted on the basis of either morpho
logical or purely formal criteria. As for new taxa
described by M. Moczydlowska and K. Nagovitsin,
the peculiar morphotype Urasphaera capitalis
undoubtedly deserves to be identified as a new genus
and species. Other taxa described in (Moczydlowska
and Nagovitsin, 2012) are questionable and reflect to a
considerable extent subjective views of the authors on
the taxonomic significance of features in the consid
ered morphotypes. The biostratigraphic analysis of the
Ura microbiota is presented in the next section dedi
cated to the age assessment of lithostratigraphic units
including the Dal’nyaya Taiga Group.
Most of the Ura limestones are characterized by
elevated δ13С values ranging from +3.6 to +5.9‰
(usually +5.1 to +5.9‰. Only a thin member at the
base of the formation yields δ13С values of approxi
mately –0.1‰ (Pokrovskii et al., 2006, 2011).
According to the same authors, the minimum
87
Sr/86Sr value in carbonates of the Ura Formation
averaged for five samples is 0.7077.
The Kalancha Formation that crowns the section of
the Dal’nyayaTaiga Group is mostly composed of car
bonate rocks with siltstone intercalations in the lower
part. The formation is well exposed on the left side of
the Lena River (Kalancha Rock and Dolgii Range)
and on the left slope of the Ura River valley near its
mouth. The lower part of the formation is dominated
by dark gray to black finegrained stromatolitic,
microphytolitic, and oolitic limestones, while its
upper part, which was suggested by some geologists to
be defined as the Dolgii Formation, consists of alter
nating gray and yellowish dolomites and black locally
stromatolitic limestones.
Stromatolites observable in the Kalancha Forma
tion are represented by two taxa: (1) endemic form
species, which was erroneously, in the opinion of one
of the authors of this work, attributed in (Dol’nik,
2000) to the form genus Baicalia distributed in the
Middle and Upper Riphean sections; (2) stratiform
species Stratifera sarmensis that occurs in southern
Siberia both in the Kalancha Formation and in the
upper part of the Uluntui Formation of the Baikal
region, which is attributed to the Vendian according to
Sr isotope chemostratigraphic data (Kuznetsov et al.,
2012).
The thickness of the Kalancha Formation in the
Lena River section is approximately 500 m
(Opornye…, 1972; Kolosov, 1975, 2000). South and
southeast of the Ura uplift, carbonate rocks of the
Kalancha Formation are rapidly replaced by a shaly
sequence, which constitutes the upper part of the Valy
ukhta Formation and is widespread in southerly areas
of the Patom Highland. Therefore, the Kalancha For
mation in sections under consideration was defined by
some researchers as the upper and middle Valyukhta
subformations (Zamaraev, 1984).
Theδ13С values in Kalancha limestones decrease
upward along the section of the formation from
+5.1‰ at the base of this unit to +2.0‰ near its top
(Pokrovskii et al., 2006).
The Zhuya Group is well exposed in several rocks
on both sides of the Lena River between the Zherba
River mouth and Macha Settlement. The almost com
plete section of the group crops out in the Kharchagai
(Kholych) Rock between the Daban Spring and village
of Tinnaya on the left side of the Lena River. The
Zhuya Group consists of two conformably occurring
formations: Nikol’skoe (lower) and Chenchen
(upper).
The Nikol’skoe Formation in its basal part is repre
sented in some sections by a member of gray polymic
tic medium to finegrained sandstones and siltstones.
It is from 50 to 80 m thick and crops out on the left side
of the Lena River near the Daban Creek mouth and in
the lower reaches of the Ura River. In the latter area,
the basal part of this member is composed of cross
bedded partly gravely sandstones with a thin layer of
carbonate breccia cemented by sandy ferruginate
material at its base that indicates an insignificant sedi
mentation break. Sandstones sampled from the Ura
River section 2 km upstream of its mouth yielded
detrital zircons. Grains of their youngest generation
form a cluster in concordia with U–Pb age of 646.9 ±
3.4 Ma (Chumakov et al., 2011a).
Laterally, the member under consideration rapidly
changes its lithology and thickness. In some outcrops,
for example, on the right side of the Lena River 6 km
downstream of the Daban Creek mouth, basal sand
stones of the formation pinch out and its base is
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
marked only by a thin (2 cm) layer of clayey gravel
stones (Bobrov, 1979). Some researchers described the
basal sand–silty member of the Nikol’skoe Formation
as the autonomous Kulleka Formation (Bobrov, 1964,
1979; Kolosov, 1975).
The overlying part of the Nikol’skoe Formation is
composed of frequently alternating variegated thin
bedded siltstones and marlstones with subordinate
intercalations of pinkish and gray limestones, the
quantity of which rapidly increases upward along the
section, reaching a maximum near its upper boundary.
The thickness of the Nikol’skoe Formation varies
from 120–150 m in the upper reaches of the Ura River
(Kokoulin, 1998) to 220–250 m in the lower courses
of this river (Chumakov, 1959; Kokoulin, 1998) and
200–360 m at the Lena River (Opornye…, 1972;
Kolosov, 1975).
Limestones of the Nikol’skoe Formation demon
strate a considerable negative anomaly ofδ13С values,
which decrease from –6.7‰ at the base of the forma
tion to –13.5‰ in its middle part. According to (Gor
okhov et al., 1995), the 87Sr/86Sr value derived from
eight determinations in three samples varies from
0.70831 to 0.71057; the upper part of the formation
yielded its minimum value averaged for six samples:
87Sr/86Sr = 0.70790 (Pokrovskii et al., 2006).
The Chenchen Formation with a gradual transition
overlies the Nikol’skoe Formation. This limestone
unit comprises two subformations. The lower subfor
mation that is assigned by some authors to the auton
omous Alyanch Formation (A.A. Predtechenskii,
1941; Chumakov, 1959; Bobrov, 1979; Melezhik et al.,
2009) consists largely of light gray stylolithic stroma
tolitic, micritic, detrital, and oolitic limestones. Some
beds of the last variety are composed of a gray matrix
and red oolites. The thickness of the subformation
increases from 200–250 m at the Lena River (Chuma
kov, 1959; Zamaraev, 1984; Kokoulin, 1998) to 600–
900 m at the Bol’shoi Patom River (Zamaraev, 1984;
Melezhik et al., 2009). The upper subformation of the
Chenchen Formation that is assigned by some
researchers to the autonomous Kholych or Khopchai
Formation (A.A. Predtechenskii, 1941; Chumakov,
1959; Bobrov, 1979; Melezhik et al., 2009) overlies the
lower one with a gradual transition. It is formed by
alternating gray, locally variegated (grayred) oolitic,
oncolitic, stromatolitic, silty, sandy, and detrital lime
stones. The last variety exhibits cross bedding. The
share of sandy limestones gradually increases upward
along the section, where they are accompanied by first
appearing intercalations of calcareous sandstones and
gravelstones as well as lenses of dolomites.
In the Ura uplift, the section of the upper
Chenchen Subformation is crowned by a 30 to 35m
thick member of brown finegrained oolitic, stroma
tolitic, and sandy dolomites and sandstones. The
member contains also rare thin intercalations of mud
stones and conglomerates with a dolomitic matrix and
scattered pebbles (Fig. 6). Locally, the member dem
STRATIGRAPHY AND GEOLOGICAL CORRELATION
369
onstrates intraformation erosional surfaces and tex
tures of sediment dehydration (teepees; Pelechaty,
1998). It is likely that deposition of the dolomitic
member of the Chenchen Formation was preceded by
a sedimentation break, which is evident from distinct
erosional features at the base of the analogous dolo
mitic member at the Molbo and Zhuya rivers located
beyond the Ura uplift. These features and increase in
the grainsize composition and share of detrital rocks
in the upper part of the formation distinctly indicate
rapid shoaling of the Chenchen basin at its terminal
development stage.
The thickness of the upper Chenchen Subforma
tion varies from 200–250 m at the Lena River (Chu
makov, 1959; Zamaraev, 1984; Kokoulin, 1998) to
350–450 m at the Bol’shoi Patom River (Chumakov,
1959; Melezhik et al., 2009). The total thickness of the
Chenchen Formation in the Ura uplift is estimated to
range from 400–600 m at the Lena River (Opornye…,
1972; Zamaraev, 1984; Kokoulin, 1998; Kontorovich,
2005) to 800–1200 m in southerly areas (Chumakov,
1959; Zamaraev, 1984; Melezhik et al., 2009).
Stromatolites contained in the Chenchen Forma
tion are represented by endemic forms attributed to
form genera Katavia and Inzeria (Dol’nik, 1982, 2000)
and a species of genus Gymnosolen also determined in
the open nomenclature. In the South Siberian stroma
tolite province, all these taxa differ from synonymous
biotas developed in other similar provinces of northern
Eurasia (Semikhatov, 1985) by their low taxonomic
diversity, sharply reduced number of taxa in common
with other provinces, and confinement of representa
tives of form genera Katavia, Inzeria, and Gymnosolen
to the Vendian section, while in the Ural, North, and
Middle Siberian provinces, these genera are charac
teristic of the Upper Riphean stromatolite assemblage
(Krylov, 1975; Komar, 1966; Semikhatov and Serebry
akov, 1985; and references therein).
Theδ13С value in bulk samples of Chenchen car
bonates increases from –9.6‰ in the middle part of
this unit to –7.6 and –8.4‰ in its upper part. The
87Sr/86Sr ratio in limestones of the Chenchen Forma
tion derived from six measurements varies from
0.70811 to 0.70870 (Gorokhov et al., 1995). Four orig
inal and six published determinations of the 87Sr/86Sr
value for limestones of the Chenchen Formation are
cited in (Pokrovskii et al., 2006). All the available mea
surements show that this ratio varies from 0.70786 to
0.70855. Among these 87Sr/86Sr values, the last authors
consider its minimum value determined for the lower
and middle part of the formation (0.7079) as the most
reliable. Similar data are presented in (Melezhik et al.,
2009). According to them, the 87Sr/86Sr value in lime
stones from the middle part of the Chenchen Forma
tion is 0.7080 and increases to 0.7086 at its top. The
last values are close to the 87Sr/86Sr ratios obtained by
A.B. Kuznetsov (private communication) for lime
stones of the Chenchen and Nikol’skoe formations at
the Zhuya River.
Vol. 21
No. 4
2013
CHUMAKOV et al.
Molbo R.
m
Lena River 5 km
upstream of Nokhtuisk
Apparent 18
Apparent, over 80
Lena Riverо@коло устья
р. Бол. Патоm
m
7
52
15
28
m
Zhuya R.
1
2
3
Apparent, over 100
Zherba Formation
Apparent 25
@р. Бол.
Джербедянка
m
Apparent 20
370
4
25
5
6
7
10
8
5
11
3.5
6
10
14
11
25
16
9
20
12
15
26
Over 300
4
14
15
16
20
17
18
Over 100
Apparent 20
Apparen 41
Chenchen Formation
18
1.6–2.7
Apparent 20
5
4
6–7
13
7.5
Fig. 6. Contact between the Chenchen and Zherba formations in the central part of the Ura uplift and on its flanks.
(1) Conglomerate with sandy matrix; (2) conglomerate with carbonate matrix; (3) sandstone pebbles; (4) limestone pebbles;
(5) dolomite pebbles; (6) black shale pebbles; (7) gravelstone; (8) quartzitelike sandstone; (9) calcareous sandstone; (10) sand
stone; (11) siltstone; (12) mudstone; (14) dolomite; (15) sandy dolomite; (16) oolitic limestone and dolomite; (17) stromatolites;
(18) glauconite. Thin continuous line designates erosional unconformity at the base of the Zherba Formation; thin dotted lines
show correlation of some members.
The “Yudoma Group” (complex or horizon) in the
Ura uplift and on the margin of the Patom folded zone
includes the Zherba and Tinnaya formations with ero
sional surfaces at the bases. They are largely represented
by different alternating rocks with the dominant role of
quartz sandstones and carbonate rocks in the Zherba
and Tinnaya formations, respectively (Fig. 3)
The names “Yudoma Group” or “Yudoma Com
plex” were proposed for deposits of the Patom High
land at times when most researchers who investigated
the Upper Precambrian sections of the Siberian Plat
form and its surrounding structures believed that all
the formations of the region separated from underly
ing rocks by unconformities and closely associated
with Lower Cambrian sections are coeval and belong
to the Vendian (reviews in (Zuravleva and Komar,
1962; Khomentovskii, 1976; Semikhatov et al., 1970,
2004)). Now, such a correlation is rejected: the Ven
dian reference sections of Siberia are established to
include analogs of several units from the type section
of the Yudoma Complex located in the UchurMaya
region. Therefore, despite the fact that the names
“Yudoma Group” or “Yudoma Complex” for the
Zherba and Tinnaya formations are traditional, they
are conditional and, undoubtedly, invalid. These tra
ditional names under no circumstances mean that
these two formations are stratigraphic analogs of the
Aim and Ust’Yudoma subformations in the type sec
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
tion of the Yudoma Complex (or group). As follows
from the data mentioned above and cited below, the
analog of the Yudoma Group type section in the Ura
uplift is represented by all the succession of the
Dal’nyaya Taiga, Zhuya, and “Yudoma” groups.
Therefore, to avoid confusion, we suggest renaming
the “Yudoma Group” of the Ura uplift the “Trekhver
stnyi Group” after the Trekhverstnyi Creek, a left trib
utary of the Lena River, into which it flows 2.5 km
upstream of Nokhtuisk. The stratotype of the Trekh
verstnyi Group comprises the Zherba and Tinnaya for
mations of the Nokhtuisk section. It is reasonable to
attribute the Trekhverstnyi Group to the Patom Com
plex, which included previously only the Zhuya,
Dal’nyaya Taiga, and Ballaganakh groups (Chumakov,
1959).
The Zherba Formation rests upon the Chenchen
Formation with considerable hiatus, which is marked
by karst features in the upper part of the Chenchen
Formation on the Ura uplift (Pelechaty, 1998; Kho
mentovskii et al., 2004) and by almost complete ero
sion of the upper dolomitic member of the Chenchen
Formation at the Molbo and Bol’shaya Dzherbedy
anka rivers (Fig. 6). This hiatus follows also from wide
regional correlations between sections of the
Chenchen and Zherba formations (Khomentovskii
et al., 2004). At the same time, development of ero
sional surfaces both below and above this main hiatus
hampers its recognition. Therefore, some authors
(Chumakov, 1959; Opornye…, 1972; Bobrov, 1979;
Zamaraev, 1984) took the base of a dolomitic member,
which crowns the Chenchen Formation and bears
erosional features at its base, for the lower boundary of
the Zherba Formation. The deposition of this member
during the Zherba time in the marginal part of the
Patom basin was followed by drastic changes in sedi
mentation patterns: mostly carbonate sediments were
replaced by sandy facies.
The best outcrops of the Zherba Formation are
located in the eastern margin of the Ura uplift: on the
left side of the Lena River opposite the Bol’shoi Patom
River mouth and opposite the Malyi Patom River
mouth (Pelechaty, 1998; Khomentovskii et al., 2004).
In these sections, the Zherba Formation consists of
three sequences. The lower sequence is over 150 m
thick. Its basal part includes frequently encountered
conglomerates composed of a sandy matrix and dolo
mite pebbles. These conglomerates demonstrate
locally downlap relations with eroded bioherms of
stromatolitic dolomites, which imply the presence of
biogenic reefs within a member (Fig. 6). The lower
sequence is mostly composed of gray crossbedded
glauconite quartzitelike sandstones (in the lower
part) with subordinate quartz gravelstones and green
ish siltstones. Most sandstone varieties are quartzose
in composition and only some of them contain notable
admixture of feldspars. The middle sequence of the
Zherba Formation approximately 200 m thick is
poorly exposed. Its exposed 40mthick part is repre
STRATIGRAPHY AND GEOLOGICAL CORRELATION
371
sented by alternating frequently calcareous black
shales and sandstones with intercalations of bitumi
nous limestones. The third sequence crowning the
section of the Zherba Formation is approximately 60–
80 m thick and known also as the Tirbees Member
(Khomentovskii et al., 2004; Kochnev and Karpova,
2010) or Tirbees Formation (Kokoulin, 1998). This
peculiar and complex sequence was previously consid
ered as the basal unit of the overlying Tinnaya Forma
tion, which is also characterized by elevated rock bitu
minosity (Chumakov, 1959; Bobrov, 1964, 1979;
Opornye…, 1972; Kolosov, 1975; Kokoulin, 1998).
The Tirbees Member begins with a bed (approximately
20 m thick) of massive and bedded black medium to
coarsegrained highly bituminous (anthroconite)
limestones with thin intercalations of calcareous
shales. Higher in the section, the member is composed
of alternating green and red marlstones and siltstones,
clayey dolomites, black bituminous limestones, and
carbonate shales. Near the top of the member, clayey
dolomites enclose two thin (5 and 12 cm) intercala
tions of black cherts and their scattered concretions 1
(Bobrov, 1979) as well as thin layers of algal siliceous–
phosphate rocks (Khomentovskii et al., 2004).
The total thickness of the Zherba Formation is esti
mated in different manners: it is 200–250 m (Kolosov,
1975; Bobrov, 1979; Kokoulin, 1998) to 500 m (Zama
raev, 1984) thick without the Tirbees Member and
350 m with it (Pelechaty, 1998; Khomentovskii et al.,
2004).
The phosphate rocks of the Tirbees Member
yielded a diverse assemblage of excellently preserved
silicified microfossils (Yakshin, 2002; Khomentovskii
et al., 2004). Yakshin described many new endemic
microfossil genera and species, in addition to well
known taxa characterized by wide stratigraphic
(Upper Riphean–Vendian–Lower Cambrian) and
geographic distributions such as Obruchevella, Oscilla
toriopsis, Glomovertella, Gloeodiniopsis, and Germino
sphaera. By its composition and diversity, this micro
biota reflects an important stage in development of
microorganisms on the Siberian Platform during the
Late Precambrian. As for many endemic species
described among this assemblage, the problem of
appropriateness and validity of identified new genera
and species for the Precambrian microbiotas should be
solved by subsequent investigations and revisions,
which still do not involve Tirbees microfossils.
Determinations of the C isotope composition in
limestones and dolomites from the terminal part of the
middle sequence of the Zherba Formation revealed
negative δ13С values and their decrease upward along
the section from –8.0 to –2.5‰. In most associated
dolomites, the δ13С values drop to –20‰, which is
thought to be explained by limestone dolomitization
and has no stratigraphic sense (Pelechaty, 1998). In the
upper sequence of the Zherba Formation (Tirbees
Member), the brief negative excursion to –5‰ is fol
lowed by the growth of the δ13С value to 2‰ and its
Vol. 21
No. 4
2013
372
CHUMAKOV et al.
decrease gradually to zero at the top of the formation
(Pelechaty, 1998).
The Tinnaya Formation. The boundary between the
Zherba and Tinnaya formations is now placed imme
diately below a 10mthick bed of coarsegrained
crossbedded sandstones and gravelstones with karst
features (Pelechaty, 1998) and erosional incisions
(Khomentovskii et al., 2004) at its base. The overlying
part of the Tinnaya Formation is composed of alter
nating members of brecciated clayey bituminous lime
stones and dolomites, which are separated by interca
lations of dark gray to black carbonaceous calcareous
clays, greenish siltstones, and massive limestone and
dolomite beds. These rocks include a thin (15 cm)
1 layer of black cherts 20 m below the top of the forma
tion (Khomentovskii et al., 2004). The thickness of the
Tinnaya Formation in the Ura uplift area is estimated
to be 220 m (Khomentovskii et al., 2004) or 334 m
(Pelechaty, 1998). The upper 150 m of the formation
yielded smallshell faunal fossils characterizing the
Anabarites trisulcatus Zone of the Upper Vendian
Nemakit–Daldynian Stage; higher layers contain Tik
sitheca sp., indicating the presence of the overlying
Purella antiqua Zone of the same stage in this section
(Khomentovskii et al., 2004; Kochnev and Karlova,
2010).
The Tinnaya carbonate rocks from the lower part of
the formation are characterized by δ13С values varying
from +2.3 to –9‰, which provide a curve with four
negative excursions (from the base upward): –3.5, –5,
–9, and –5.5‰ (Fig. 3). They are separated by nar
row intervals of the section also with negative but rela
tively elevated δ13C values (Pelechaty, 1998). In the
upper part of the Tinnaya Formation, the δ13C value
varies from –4.8 to ⎯3.0‰ and decreases to –5.5‰
at the base of the Nokhtuisk Formation and then
increases to zero at higher levels of this unit (Khomen
tovskii et al., 2004).
LOWER CAMBRIAN
The Nokhtuisk Formation rests upon the Tinnaya
Formation with insignificant hiatus (Khomentovskii
et al., 2004). The contact between these formations
and the lower part of the Nokhtuisk Formation com
posed of alternating variegated mudstones, marl
stones, and stromatolitic dolomites are well exposed
on the left side of the Lena River 3 km upstream of the
Nokhtuisk Settlement. In this area, the basal layers of
the Nokhtuisk Formation and its lower 50 m yield
abundant smallshell fossils characteristic of the Tom
motian Aldanocyathus sunnaginicus Zone, the basal
zonal unit of the Lower Cambrian section (Khomen
tovskii et al., 2004; Kochnev and Karlova, 2010).
VENDIAN AGE OF THE DAL’NYAYA TAIGA,
ZHUYA, AND “YUDOMA” GROUPS:
ARGUMENTS IN FAVOR
The lower boundary of the Vendian section in the
Ura uplift area is distinctly definable at the base of the
Nokhtuisk Formation on the basis of the replacement
of the faunal assemblage characterizing the Purella
antiqua Zone of the Vendian Nemakit–Daldynian
Stage by fossils belonging to the Aldanocyathus sun
naginicus Zone of the Lower Cambrian. The lower
boundary of Vendian strata in this section is still
ambiguous because of insufficient available data,
although the distribution of organic remains in the
Dal’yaya Taiga Group and chemostratigraphic evi
dence (Pokrovskii et al., 2006; Melezhik et al., 2009)
provide grounds for the assumption that the largest
upper part of this group should be attributed to the
Vendian. This is confirmed, for example, by finds of
diverse Pertatatakatype acanthomorphic acritarchs in
the Ura Formation (Chumakov et al., 2007; Vorob’eva
et al., 2008a; Golubkova et al., 2010; Sergeev et al.,
2010, 2011) and Vendian form Beltanelloides soriche
vae in the lower subformation of the Barakun Forma
tion in the Ura River section (Leonov and Rud’ko,
3
2012). The find of Pertatatakatype acanthomorphic
acritarchs represented in the Ura Formation by the
peculiar assemblage serves as a main criterion for dat
ing this unit. The lower part of the Ura Formation
yielded the following Pertatatakatype acritarchs and
other fossils (Sergeev et al., 2011): Ancorosphaeridium
magnum, A. minor, Appendisphaera tenuis, A. minima,
Appendisphaera sp., Archaeotunisphaeridiam aff. fim
briatum, Bullatosphaera velata, Cavaspina cf.
C. acuminata, C. basiconica, Eotylotopalla strobilata,
E. aff. delicata, Gyalosphaeridium minutum, Knol
lisphaeridium maximum, Multifronsphaeridium pelo
rium, ?Sinosphaera rupina, Tanaium conoideum,
T. digitiformis, T. tuberosum, Variomargosphaeridium
litoschum, Aimia aff. gigantica, Leiosphaeridia spp.,
Schizofusa zangwenlongii, Digitus fulvus, unnamed fil
amentous microfossils, Obruchevella sp., Polytrichoides
lineatus, Rugosoopsis tenuis, Segmentothallus aff. S. aspe
rus, Siphonophycus spp., Ceratophyton sp. cf. Cucumi
forma sp., unnamed forms 1–5. This assemblage indi
cates that the Ura Formation represents an analog of
the second complex palynozone of Pertatataka acri
tarchs established in the type section of central Austra
lia (Grey, 2005).
As was mentioned, Moczydlowska and Nagovitsin
(2012) revised the microbiota from the Ura Formation
using in fact the same material analyzed by V.N. Ser
geev and colleagues. In doing so, they demonstrated
3 The find of Beltanelloides sorichevae in this section indicates that
these fossils previously known from the upper layers of the type
Vendian section in the East European Platform (Fedonkin et al.,
2007) are characterized by a wider stratigraphic distribution.
Nevertheless, this fact provides no grounds for excluding this
species from the list of characteristic Vendian taxa.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
the subjective view on the taxonomic significance of
morphological features and defined three new genera
and nine new species, renaming the previously
described taxa. Such a procedure provided grounds for
them to arrive at the conclusion on the endemic char
acter of the Ura microbiota and its older age as com
pared with other Pertatataka biotas of Siberia and
younger age as compared with sediments of the first
palynozone defined in the lower part of the Lower
Vendian Doushantuo Formation in South China
(McFadden et al., 2009). In our opinion, the available
facts indicate that the Ura Formation corresponds to
the Grey’s second complex palynozone.
The U–Pb (SHRIMP) dating of detrital zircons
from the base of the Nikol’skoe Formation cropping
out near the Ura River mouth yielded important infor
mation on age of upper layers of the Patom Complex
(Chumakov et al., 2011a). On the curve of the relative
probability, several members dated at 2900, 2070,
2500, 2000, and 1800 Ma are definable on the basis of
the 206Pb/238U and 207Pb/206Pb values, which implies
erosion of the Archean and Lower Proterozoic base
ment of the Siberian Platform. For determining the
minimum age of upper layers of the Patom Complex,
the most interesting is the youngest zircon generation
extracted from the Nikol’skoe Formation. Zircons of
this generation are divisible in two groups on the basis
of both the 206Pb/238U and 232Th/238U values. The
older group of grains is characterized by the 232Th/238U
ratios varying from 0.4 to 1.1, while in the 206Pb/238U–
207Pb/238U coordinates, the group with age of 704.3 ±
4.5 Ma (1σ, MSWD = 0.90) is definable around the
concordia. The younger group of grains demonstrates
the lowered 232Th/238U value ranging from 0.2 to 0.7
and forming in the abovementioned coordinates the
concordia with age of 646.9 ± 3.4 Ma (1σ, n = 48,
MSWD = 0.900077). Thus, U–Pb (SHRIMP) ages
obtained for detrital zircons indicate that basal sand
stones of the Nikol’skoe Formation are younger than
646.9 ± 3.4 Ma, i.e., younger as compared with age
accepted now for the lower boundary of the Vendian
System equal to 650 Ma (Dopolneniya…, 2000).
The position of the Vendian lower boundary in the
Ura uplift section may be derived from stratigraphi
cally important interchangeable features characteris
tic of some sections, which exhibit similarity with sec
tions of the Dal’nyaya Taiga, Zhuya, and Trekhverst
nyi groups. In this regard, the sections of the following
three regions are promising: Yangtze Platform of
South China, eastern and northern Oman, and north
eastern margin of the East European Platform (Fig. 7).
In these regions, the Vendian sections demonstrate the
succession of several chemostratigraphic, biostrati
graphic, and climatic events partly dated and regis
tered also in the Ura section. Let us trace these events
in the abovementioned sections (from the top down
ward).
(1) The Ura (Khomentovskii et al., 2004; Kochnev
and Karlova, 2010) and China (Steiner et al., 2007;
STRATIGRAPHY AND GEOLOGICAL CORRELATION
373
Ishikawa et al., 2008) sections include paleontologi
cally substantiated analogs of the Vendian Nemakit–
Daldynian Stage.
(2) Brief but significant negative δ13С anomalies
(from –5 to –13‰) are established near the base of
the member with the Nemakit–Daldynian fossils in
the Ura and China sections and at a close level in tuf
faceous sediments dated by the U–Pb zircon method
at 542 Ma (Brasier et al, 2000; Bowring et al., 2007) in
the Oman section (Fig. 7). In the Ura uplift section,
the ascending shoulder of a similar anomaly (Fig. 3) is
established in the middle part of the Zherba Forma
tion (Pelechaty, 1998). In China, this anomaly, named
the Bace (Zhu et al., 2007a) or EN4 (Zhou and Xiao,
2007; Zhou et al., 2011) anomaly, is documented at
the base of the Zhujiaqing Formation. In Oman, a
similar situation is recorded in the lower part of the
Fara Formation, where it is designated by the letter Z
(Walter et al., 2000). Similar anomalies are also known
at the bases of sedimentary sequences with fossils
characteristic of the Nemakit–Daldynian Stage in the
McKenzie Mountains of Canada (Walter et al., 2000)
and India (Jiang et al., 2003).
(3) In South China, the significant (≥–10‰) neg
ative δ13С anomaly named the Dounce (Zhu et al.,
2007a) or EN3 (Zhou and Xiao, 2007; Zhaou et al.,
2011) anomaly is established in the upper part of the
Doushantuo Formation. In Oman, the similar event
called the Shuram anomaly (up to 14‰) is registered
in the upper part of the Nafun section (Le Guerroue,
2010). By their amplitudes and stratigraphic positions,
both of these anomalies are similar to the negative
Zhuya one (Fig. 7). Correlation of the Zhuya anomaly
with its Dounce and Shuram counterparts is con
firmed by similarity in 87Sr/86Sr values in their consti
tuting carbonate rocks. These values are estimated to
be 0.7080–0.7084 for the Zhuya (Pokrovskii et al.,
2006; Melezhik et al., 2009), 0.7083–0.7084 for the
Dounce (Jiang et al., 2007), and 0.7080–0.7088 for
the Shuram (Le Guerroue et al., 2006, Le Guerroue,
2010) anomalies. Similar 87Sr/86Sr values are charac
teristic of sediments aged 580–570 Ma (Halverson and
ShieldsZhou, 2011). In the East European Platform,
similar results are obtained for the lower part of the
Vendian Redkino Horizon on the basis of U–Pb dates
of zircons from tuffs and corresponding interpolations
(Sokolov, 2011, 2012, Grazhdankin, 2011). These
estimates are consistent with radioisotopic data con
cerning the Dounce and Shuram anomalies. U–Pb
TIMS dates of approximately 551 and 555 Ma are
available for volcanogenic zircons from the upper part
of the Doushantuo Formation above the Dounce
anomaly (Condon et al., 2005; Zhang et al., 2005). At
the same time, according to U–Pb dating of detrital
zircons, the Shuram anomaly of Oman is younger than
600 Ma (Rieu et al., 2007). These measurements place
the upper and lower age limits for the Dounce and
Shuram anomalies at 550 and 600 Ma, respectively.
Such values are also suitable for assessing age limits of
Vol. 21
No. 4
2013
R32
V1
VII–III
VIV
Є1
~640
635
~560
555
542
535
Bugarikhta
Mariinskaya
STRATIGRAPHY AND GEOLOGICAL CORRELATION
1
–10
<647
0.7086
Vol. 21
2
3
No. 4
0.7078
4
5
Datangpo;
6
8
9
10
11
12
20
<644
Saglakh
Fiqa
Hadash
Masirah
Bay
Khufai
Shuram
Buah
0.7092
14
0.7080
21
13
<610
<600
0.7085
0.7088
0.7086
<620
544 U
541
15
δ13C‰
–10
0 5
Oman (5, 6, 7)
Fara
542
551, UPb, t 18 0.7086 19
7
0.7083
0.7087
0.7085
0.7084
656 δ13C‰
663
Nantuo 636
635
621
Dengying
551, 555
Zhujiaqing
South China (2, 3, 4)
725 16 <620 17
0
10
δ13C‰
0.7073
Barakun
Bol’shoi Patom
0.7077
Ura
Kalancha
Nikol’skoe
Chenchen
Zherba
Tinnaya
El’gyan
Nokhtuisk
Doushantuo
Ura Uplift (1)
ARA
NAFUN
Ma
ZHUYA
DAL’NYAYA TAIGA
BALLAGANAKH
Pinsk
Lapich
Blon
Glussk
Vychegda
567
REDKINO
551, UPb, t
555
558
KOTLIN
ROVNO
Eastern Europe (8, 9, 10)
VCH
LAPLAND
374
CHUMAKOV et al.
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
the Zhuya anomaly, which is correlated with these
events, which serves as additional evidence in favor of
its Vendian age.
(4) The rocks immediately below the Dounce
anomaly in the Doushantuo Formation yield a diverse
assemblage of acanthomorphic acritarchs (ECAP
assemblage), which is similar in its general appearance
to the Lower Vendian Ura and Kel’tma assemblages of
the East European Platform. The Kel’tma assemblage
characterizes the autonomous Vychegda Horizon,
which is older as compared with the Vendian Redkino
Horizon of the East European Platform. In its taxo
nomic composition, the Kel’tma assemblage is corre
lated with the first ECAP zone in the stratotype sec
tion of Australia (Veis et al., 1996; Vorob’eva et al.,
2006, 2007, 2008b, 2009a, 2009b). This provides addi
tional grounds for correlating the sediments sand
wiched between the Nemakit–Daldynian Stage and
strata with the Ura acritarch assemblage with the
Upper Vendian.
The largest acanthomorphic acritarchs are
recorded near the base of the Doushantuo Formation
5 m above the top of cap dolomites associated with til
lites of the underlying Nantuo Formation. Zircons
from tuff intercalations in cap dolomites and from
tuffs sampled 5 m above the top of cap dolomites are
dated by the U–Pb method at 635.2 ± 0.6 and 632.5 ±
0.5 Ma, respectively (Condon et al., 2005). At the
same time, it is impossible to establish age relation
ships between zonal units of the Doushantuo (McFad
den et al., 2009) and type biozones defined in (Grey,
2005) because of taxonomic difficulties. In their pub
lications, Chinese researchers to date have used some
taxa names, such as Meghystrichosphaeridium and
Polygonum, which were acknowledged after multiple
revisions (Grey, 2005; Moczydlowska, 2005; etc.) to
be invalid.
It should be emphasized that the Torgo Formation
immediately overlying stratigraphic analogs of the Ura
Formation on the western slope of the Aldan Shield
375
and correlated with the Zhuya Group contains the
impoverished assemblage of acanthomorphic acri
tarchs that includes Cavaspina and some other taxa
characteristic of the Pertitatakatype microbiota. Pre
viously, these microfossils were erroneously attributed
to genera and species of Upper Riphean acanthomor
phic acritarchs (Kolosova, 1991). The recent find
indicates that final extinction of Pertatatakatype
microfossils was asynchronous with the onset of the
Dounce–Shuram–Zhuya negative carbon excursion,
as was assumed by some researchers (Zhu et al., 2007a,
2007b; Chumakov, 2010; etc.).
(5) The lower part of the Doushantuo Formation of
South China and the interval of the Khufai and
Masirah Bay formations of Oman are dominated by
considerable positive δ13С values (ranging from +5 to
+6‰). The middle parts of these large intervals in
China and Oman exhibit brief negative δ13C excur
sions (Fig. 7). The similar interval of positive δ13С val
ues (from +5 to +8‰) is also characteristic of the
largest upper part of the Dal’nyaya Taiga Group,
although without a brief negative excursion in its mid
dle part. The latter could be missed owing to the insuf
ficient density of measurements in this interval of the
Ura section.
(6) The negative peaks at bases of these wide posi
tive δ13C intervals under consideration corresponding
to cap dolomites of glacial horizons are well expressed
in the Ura, China, and Oman sections (Pokrovskii
et al., 2006; Le Guerroue, 2010; Jiang et al., 2011).
(7) In all three compared sections, cap dolomites
are underlain by glacial horizons of the Bol’shoi
Patom Formation on the Ura uplift, Nantuo Forma
tion in South China, and Fiqa Formation in Oman.
The comparison between the Ura, South China,
and Oman sections shows that the succession of
chemostratigraphic and, partly, biotic events in the
section from the base of the Cambrian to glacial hori
zons is similar. Such a similarity is particularly signifi
cant between the Ura and South China sections, pro
Fig. 7. Correlation of Vendian sections of the Ura uplift with sections of South China, Oman, and Eastern Europe.
(1) Glacial sediments; (2) cap carbonates; (3) trilobites; (4) faunal assemblage of the Aldanocyatus sunnaginicus Zone, lower unit
of the Tommotian Stage; (5) faunal assemblage of the Purella antiqua Zone, Nemakit–Daldynian Stage, Upper Vendian; (6) fau
nal assemblage of the Anabarites trisulcatus Zone, Nemakit–Daldynian Stage, Upper Vendian; (7) sabelliditids; (8) claudinids;
(9) Upper Vendian microfossils; (10) Lower Vendian ECAPtype microfossils, including the assemblage from the upper zone of
the Doushantuo Formation, according to (McFadden et al., 2009); (11) Lower Vendian microfossils from the lower zone of the
Doushantuo Formation, according to (McFadden et al., 2009); (12) nonskeletal Metazoa; (13) Eocholinia and Archiphasma
algae; (14) vendotenids; (15) Beltanelloides sorichevae. Dates (Ma): (16) U–Pb SHRIMP/TIMS on volcanogenic zircons,
(17) U–Pb SHRIMP/TIMS on detrital zircons; (18) U–Pb SHRIMP/TIMS on zircons from volcanics (t); (19) 87Sr/86Sr ratios
in carbonates; (20) indications of stratigraphic hiatuses; (21) stratigraphic unconformities. ( ~
C ) Cambrian; (VIV) Nemakit–Dal
dynian Stage of the Vendian System; (VII–III) Kotlin and Redkino horizons of the Vendian System; (VI) Lapland Horizon of the
Vendian System; (VCH) Vychegda Horizon of the Vendian System; (R32) upper part of the Upper Riphean. Main sources:
(1) Chumakov, 1959, Bobrov, 1964; Khomentovskii et al., 2004; Pokrovskii et al., 2006; Chumakov et al., 2007, 2011a; Vorob’eva
et al., 2008a; Melezhik et al., 2009); Kochnev and Karlova, 2010; Leonov and Rud’ko, 2012; (2) Zhou and Xiao, 2007; Zhu et al.,
2007a, 2007b; (3) McFadden et al., 2009; Jiang et al., 2011; (4) Zhang et al., 2011; etc.); (5) Le Guerroue et al., 2006;
(6) Le Guerroue, 2010; (7) Rieu et al., 2007; etc.; (8) Sokolov, 1997, 2011, 2012; (9) Veis et al., 1996; Vorob’eva et. al., 2006,
2008a, 2009a, 2009b; (10) Chumakov, 1978, 1992, 2009; etc. Names of groups and horizons are given in capital letters. (VCH)
Vychegda Horizon.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
376
CHUMAKOV et al.
viding grounds for correlation of the glacial Bol’shoi
Patom Formation with the glacial Nantuo Formation
of South China. The age of the latter unit is deter
mined owing to several U–Pb dates obtained for detri
tal zircons (Zhang et al., 2011). The base of the cap
dolomite crowning the Nantuo Formation is dated at
635.6 ± 0.5 Ma; its lower part is dated at 636.3 ± 4.9 Ma;
the upper part of the Datangpo Formation, which
unconformably underlies the Nantuo Formation, is
dated at 656 ± 3 Ma. In Oman, the glacial Fiqa For
mation, the age of which is estimated by the U–Pb
method on detrital zircons to be <644 Ma (Rieu et al.,
2007), corresponds likely to the Bol’shoi Patom For
mation. Such a correlation allows the Bol’shoi Patom
Formation to be considered as being older than
635 Ma and younger than 644 Ma ago; i.e., it corre
sponds to the basal glacial part of the Lapland Horizon
in the Vendian stratotype (Sokolov, 1997, 2012).
Thus, the available data and aforementioned corre
lations indicate that the interval of the Trekhverstnyi,
Zhuya, and Dal’nyaya Taiga groups of the Ura uplift
sandwiched between the top of the Nemakit–Daldy
nan Stage and basal Vendian Lapland Horizon corre
sponds (or is very close) by its range to the Vendian in
the stratotype area and represent together analogs of
the main horizons of the Vendian stratotype: Nema
kit–Daldyn, Vychegda, Kotlin, Rovno, and Lapland.
The completeness and exact boundaries of these hori
zons in the Ura Section are as yet unclear and require
further investigations.
REGIONAL CORRELATIONS
OF VENDIAN SECTIONS IN THE URA UPLIFT
In regions surrounding the Baikal folded domain,
the lithology and structure of Vendian sections dem
onstrate certain variations. Nevertheless, the sections
of these regions are well correlative with units of the
Ura type section. They are mostly correlated by trac
ing some reference formations (Fig. 8). The main role
in this process belongs to the following stratigraphic
units: (1) terrigenous Ballaganakh Group preceding
Vendian strata; (2) overlying glacial diamictites of the
Bol’shoi Patom Formation and its analogs; (3) Zhuya
Group, which is characterized by a peculiar composi
tion and bedding succession; (4) Zherba Formation.
These deposits are traced from the Ura uplift eastward
and southeastward along the eastern branch of the
Patom fold arc (Chumakov, 1959, 1993; Opornye…,
1972), then to the Berezovo trough centroclinal and
farther to the western slope of the Aldan Shield
(Zhuravleva et al., 1959; Chumakov, 1959, 1993;
Opornye…, 1972). In the southwestern direction, Ven
dian complexes are well traceable from the Ura uplift
up to the Bol’shaya and Malaya Chuya rivers
(Golovenok et al., 1963; Chumakov, 1993; Opornye…,
1972). Such correlations are confirmed by the condi
tional state geological survey, scale 1 : 2000000 (Ivanov
et al., 1995; Kokoulin, 1998; etc.).
The eastern branch of the Patom arc south of the
Ura uplift is characterized by an elevated thickness of
sediments under consideration and significant facies
changes in the Dal’nyaya Taiga Group. In the Malyi
Patom, Zhuya, Molbo, and Bul’bukhta river basins,
glacial diamictites of the Bol’shoi Patom Formation
are replaced by black shales and sandstones, which are
united into the Dzhemkukan Formation, while the
Ura and Kalancha formations are replaced by the
Valyukhta Formation consisting of dark gray to black
shales with subordinate sandstone and limestone
intercalations. Southeast of these areas in the southern
centroclinal of the Berezovo trough in the Dzhelinda
and Sen river basins, the basal part of the Dal’nyaya
Taiga Group again contains glacial sediments united
into the Nichatka Formation correlated with the
Bol’shoi Patom Formation. In this area, the Barakun
and Valyukhta formations are replaced by the Kumakh
Ulakh carbonate–terrigenous and Sen sandstone–
dolomite formations, respectively. The latter units are
traceable in the eastern direction up to the Chara and
Tokko rivers on the western slope of the Aldan Shield.
In the eastern part of this region, the thickness of the
Vendian section decreases. The Nikol’skoe and
Chenchen formations are replaced by the Torgo For
mation, the Sen Formation becomes divided into the
basal Imalyk terrigenous and Tokko carbonate forma
tions, and the Kumakhulakh and Nichatka formations
pinch out (Zhuravleva et al., 1959; Petrov, 1966).
In the western branch of the Patom arc and North
Baikal Highland, the Vendian section is similar to the
section of its eastern branch, differing only in the
lithology of the Dzhemkukan Formation, which is
composed largely of glacial sediments in these areas.
Southwest of the Malaya Chuya River head, the Balla
ganakh Group and lower glacial part of the Dal’nyaya
Taiga Group pinch out, while analogs of the upper part
Fig. 8. Correlation of Vendian sections of the Ura uplift, peripheral zone of the Baikal fold system, and western slope of the Aldan
Shield, according to (Zhuravleva et al., 1959, 1961, 1969; Opornye…, 1972; Chumakov, 1993; Ivanov et al., 1995; Khomentovskii,
2008; Khomentovskii et al., 2004; Sovetov and Komlev, 2005; Kochnev and Karlova, 2010; Kuznetsov et al., 2012; etc.).
(1) Glacial sediments; (2) cap carbonates; (3) Beltanelloides sorichevae; (4) Lower Vendian acanthomorphic microfossils; (5) U–Pb
age of detrital zircon; (6)) nonskeletal Metazoa; (7) faunal assemblage of the Tommotian Aldanocyatus sunnaginicus Zone, Lower
Cambrian; (8) faunal assemblage of the Purella antiqua Zone, Nemakit–Daldynian Stage, Vendian; (9) faunal assemblage of the
Anabarites trisulcatus Zone, Nemakit–Daldynian Stage, Vendian; (10) sabellidites; (11) indications of stratigraphic hiatuses;
1
(12) base and top of cap dolomites; (13) 87Sr/86Sr ratios in carbonate rocks; (14) Pb–Pb isochron age of limestones. ( ~
C 1 ) Tom
motian Stage of the Lower Cambrian; (V) Vendian; (R) Riphean.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
STRATIGRAPHY AND GEOLOGICAL CORRELATION
R3?
V
Є11
Vol. 21
6
Nikol’skoe
Nikol’skoe
No. 4
2013
1 cd 2
3
4 <647 5
7
8
Bugarikhta
9
10
11
Bugarikhta
Bugarikhta
Mariinskaya
Dzhemkukan
Barakun
Valyukhta
Nichatka
cd
Kumakhulak
Sen
Torgo
Zherba
Tinnay
Yuedei
Chaya Rive
Aldan Shield
12 0.7086 13 PbPb 560 ± 30 14
Mariinskaya
Mariinskaya
0.7073
0.7077
Bol’shoi Patom
cd
Barakun
Ura
Kalancha
<647
Nikol’skoe
Zherba
Zherba
Nikol’skoe
Tinnay
Tinnaya
Chenchen
Yuedei
Nokhtuisk
Chenchen 0.7086
Zhuya River
Ura Uplift
Dzhemkukan
cd
cd
cd
Bugul’deika
Member
Barakun
Goloustnaya
Valyukhta
Chenchen
Chenchen
Uluntui
Zherba
Tinnaya
Nokhtuisk
Bol’shaya Chuya River
Zherba
Min
Usatovo
Chaya Rive
Goloustnaya
PbPb 560 ± 30
0.7087
0.7084
Uluntui
Kachergat
Ushakovo
Ayankan
Ayankan
Ussol’e
South Baikal region
Valyukhta
Peripheral zone of the Baikal fold region
0.7073
0.7080
0.7083
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
377
378
CHUMAKOV et al.
of the Dal’nyaya Taiga Group and Zhuya Group are
well recognizable in sections along the Chaya River
and the head area of the Malaya Chuya River
(Opornye…, 1972).
The Chaya section is transitional between the
Patom and nearBaikal sections; therefore, the Kalan
cha Formation at the Chaya River was called by some
researchers also both the Kalancha and Goloustnaya
or Uluntui formations (Opornye…, 1972). The analog
of the Chenchen Formation at the Chaya River is over
lain by sediments, which are correlated by their lithol
ogy and position in the section with the Trekhverstnyi
Group of the Ura uplift. From the Chaya River, these
sediments are traced as the Goloustnaya and Uluntui
formations and “Yudoma Group” or “Yudomian” in
the southwestern directions along the western margin
of the North Baikal Highland and Baikal Range up to
the southern Baikal region (Opornye…, 1972). In the
Kurgun River basin, located in the southern part of the
last region, the Goloustnaya Formation is built up by a
member of glacial sediments (diamictites, conglomer
ates, and sandstones), which is named the Bugul’deika
Member (Sovetov and Komlev, 2005).
The traditional correlation of NearBaikal sections
with the Patom section based on geological (biostrati
graphic and event) criteria is confirmed by recent Sr
and C isotopic chemostratigraphic methods and
Pb⎯Pb isochron dating of the least altered limestones
from the upper part of the Uluntui Formation: 560 ±
30 Ma (Kuznetsov et al., 2012).
The δ13C values in a thin dolomite member occur
ring in the upper part the Goloustnaya Formation
(basal unit of the Baikal Complex) in the type section
of the complex increases from –2.6‰ at the base of
the member to +2.8‰ at its top. Taking into consid
eration the occurrence of the Goloustnaya Formation
on diamictites of the Bugul’deika Member, these val
ues can be correlated with the abovementioned δ13C
values obtained for the basal part of the lower Barakun
Subformation. In the 600mthick member of lime
stones occurring at the top of the Uluntui Formation
in the same section of the Baikal Complex, the values
vary around +4.7‰, deviating from this value usually
by 0.8–0.9‰ (Kuznetsov et al., 2012). Variations of
δ13C in the upper part of the Uluntui Formation are
comparable with their changes in sections of the
Dal’nyaya Taiga Group in the interval from the upper
part of the lower Barakun Subformation to the lower
part of the Kalancha Formation.
Recent measurements in samples which met very
strict requirements on geochemical preservation of
carbonate rocks (Mg/Ca < 0.05, Mn/Sr < 0.03,
Fe/Sr < 0.4, δ13O > –8‰) yielded information of
87Sr/86Sr values in them, which were from 0.70842 to
0.70874 (Kuznetsov et al., 2012). In terms of Sr chro
nostratigraphy, this implies that early diagenesis of the
analyzed upper Uluntui rocks corresponds within the
error limits with their Pb–Pb age.
The available data on correlation of the
Bugul’deika Member and Goloustnaya and Uluntui
formations of the Baikal Complex with the Dal’nyaya
Taiga Group of the Patom Highland disprove the tra
ditional opinion in the Russian geological literature
that this complex should be attributed either to the
upper part of the Middle Riphean and lower part of the
Upper Riphean (Dol’nik, 1982, 2000; Stanevich et al.,
2007) or to the Baikalian, a unit dating back to 850–
600 Ma (Opornye…, 1972; Khomentovskii et al., 1998;
Khomentovskii and Postnikov, 2001, Khomentovskii,
2002). The new data show that the Baikal Complex in
the range of the Bugul’deika Member and Goloust
naya, Uluntui, and Kachergas formations should be
correlated with the Vendian System (Kuznetsov and
Letnikova, 2005; Kuznetsov et al., 2012).
CONCLUSIONS
The recent chemostratigraphic, paleontological,
and radioisotopic data indicate that the Dal’nyaya
Taiga, Zhuya, and Trekhverstnyi groups of the Ura
uplift are the Vendian in age. Correlations of these
units with wellstudied Upper Proterozoic sections of
other regions support this inference. The upper
boundary of the Vendian System in the Ura uplift sec
tion is established at the base of the Nokhtuisk Forma
tion on the basis of biostratigraphic data (Khomen
tovskii et al., 2004; Kochnev and Karlova, 2010). Its
lower boundary in this section is placed with high con
fidence at the base of the glacial Bol’shoi Patom For
mation on the basis of finds of diverse Vendian acanth
omorphic acritarchs (ECAP) in the Ura Formation
and Beltanelloides sorichevae in the lower part of the
Barakun Formation and also on the basis of the corre
lation of the Bol’shoi Patom Formation with glacial
sediments of the Nantuo and Fiqa formations of
China and Oman, respectively, and with the Lapland
Horizon of Eastern Europe. Consequently, sediments
sandwiched between the base of the Nokhtuisk For
mation and the base of the Bol’shoi Patom Formation
should be attributed to the Vendian System.
(2) Correlation of the Ura Formation with East
European, China, and Oman Vendian sections with
reliable radioisotopic dates and some biostratigraphic
reference levels provide grounds for the assumption
that the Vendian section of the Ura uplift includes the
Kotlin, Redkino, and Lapland sediments, i.e., main
units of the Vendian System, in addition to the Nema
kit–Daldyn Horizon. The position of boundaries and
stratigraphic ranges in the Ura section need further
investigations.
(3) Correlation of the Ura section with Vendian
sequences in surrounding structures of the Baikal
folded region and on the western slope of the Aldan
Shield shows that the Vendian section in the Ura uplift
area represents the most complete succession of these
sediments in the spacious region under consideration.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
(4) As compared with these sections, the Vendian
succession on the Ura uplift is better substantiated by
paleontological and chemostratigraphic data and less
altered by secondary processes, well exposed, and eas
ily accessible for investigation.
All these properties allow the Vendian section of
the Ura uplift to be recommended as a regional refer
ence section of the Vendian System for the southern
part of Middle Siberia.
ACKNOWLEDGMENTS
We are grateful to M.V. Leonov, S.V. Rud’ko, and
A.B. Kuznetsov for the permission to use their unpub
lished materials; Yu.K. Sovetov for valuable recom
mendations; and O.A. Petrovichev for his help in pre
paring the manuscript. This work was supported by the
Russian Foundation for Basic Research (project
nos. 110500232, 100500294, 110592692IND)
and Program no. 28 of the Presidium of the Russian
Academy of Sciences.
Reviewer M.A. Fedonkin
REFERENCES
Bobrov, A.K., Geologiya Predbaikal’skogo kraevogo progiba
(Geology of the Baikal marginal foredeep), Moscow:
Nauka, 1964 [in Russian].
Bobrov, A.K., Stratigrafiya i paleogeografiya otlozhenii
verkhnego dokembriya Yuzhnoi Yakutii (Stratigraphy and
paleogeography of Upper Precambrian deposits of South
Yakutia), Yakutsk: Yakutskoe Knizhn. Izd., 1979 [in Rus
sian].
Bowring, S. A., Grotzinger, J. P., Condon, D. J., et al.,
Geochronological constraints on the chronostratigraphic
framework of the Neoproterozoic Huqf Supergroup, Am. J.
Sci., 2007, vol. 307, pp. 1097–1145.
Brand, U. and Viezer, J., Chemical diagenesis of a multi
component carbonate system1: trace elements, J. Sedi
ment. Petrol., 1980, vol. 50, pp. 1219–1236.
Brasier, M., McCarron, G., Tucker, R., et al., New UPb
zircon dates for the Neoproterozoic Ghubran glaciation
and for the top of the huqf supergroup, oman, Geology,
2000, vol. 28, pp. 175–178.
Chumakov, N.M., Vendian reference section of Central
Siberia and the Neoproterozoic ice ages, Proc. Conf. on
Neoproterozoic sedimentary basins, Grazhdankin D.V.,
Marusin, V. V., Eds., Novosibirsk, 2011b, pp. 16–17.
Chumakov, N.M., About stratigraphy of northern margin of
the Patom Highlands, Dokl. Akad. Nauk SSSR, 1956,
vol. 111, no. 4, pp. 863–865.
Chumakov, N. M., Stratigraphy and Tectonics of the south
western part of the Vilyui Basin, in Tektonika SSSR. T. IV
(Tectonics of the USSR. Vol. IV), Moscow: Izd. AN SSSR,
1959, pp. 345–460.
Chumakov, N. M., Dokembriiskie tillity i tilloidy (Precam
brian tillites and tilloides), Moscow: Nauka, 1978 [in Rus
sian].
Chumakov, N. M., The problems of old glaciations (pre
Pleistocene glaciogeology in the USSR), USA: Harwood Aca
demic Publishers, 1992.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
379
Chumakov, N. M., Riphean Middle Siberian glaciohorizon,
Stratigr. Geol. Correlation, 1993, vol. 1, no. 1, pp. 21–34.
Chumakov, N. M., Neoproterozoic glacial events in Eur
asia, Developments in Precambrian Geology, 2009, vol. 16,
pp. 389–403.
Chumakov, N. M., Precambrian glaciations and associated
biospheric events, Stratigr. Geol. Correlation, 2010, vol. 18,
no. 5, pp. 3–15.
Chumakov, N. M., Late Proterozoic African glacial era,
Stratigr. Geol. Correlation, 2011, vol. 19, no. 1, pp. 3–23.
Chumakov, N. M., Glacial deposits of the Nichatka Forma
tion, Chara River basin and review of Upper Precambrian
diamictites of Central Siberia, Mem. Geol. Soc. London,
2011a, no. 36, pp. 297–302.
Chumakov, N. M. and Krasil’nikov, S. S., Lithological fea
tures of Riphean tilloides of the Ura Uplift, Litol. Polezn.
Iskop., 1991, no. 3, pp. 58–78.
Chumakov, N. M., Kapitonov, I. N., Semikhatov, M. A.,
et al., Vendian age of the upper part of the patom complex
in Middle Siberia: U/Pb LAICPMS dates of detrital zir
cons from the Nikol’skoe and Zherba Formations, Stratigr.
Geol. Corellation, 2011a, vol. 18, no. 2, pp. 115–119.
Chumakov, N. M., Linnemann, U., Khofmann, M., and
Pokrovskii, B. G., Neoproterozoic ice sheets of the Siberian
platform: UPbLaICPMS ages of detrital zircons from
the Bol’shoiPatom formation and the geotectonic position
of its provenance, Stratigr. Geol. Correlation, 2011b, vol. 18,
no. 6, pp. 105–112.
Chumakov, N. M. and Semikhatov, M. A., Riphean and
Vendian of the USSR, Precambrian Res., 1981, vol. 15,
nos. 3–4, pp. 229–254.
Chumakov, N. M., Pokrovskii, B. G., and Melezhik, V. A.,
Geological history of the Patom Highlands, Late Precam
brian, Central Siberia, Dokl. Akad. Nauk, 2007, vol. 413,
no. 3, pp. 379–383.
Chumakov, N. M., Pokrovsky, B. G., and Melezhik, V. A.,
The glaciogenic Bol’shoy Patom Formation, Lena River,
Central Siberia, Mem. Geol. Soc. London, 2011, no. 36,
pp. 309–316.
Condon, D. J., Zhu, M., Bowring, S., et al., UPb ages
from the Neoproterozoic Doushantuo Formation, China,
Science, 2005, vol. 308, pp. 95–98.
Denison, R. E., Koepnick, R. B., Fletcher, A., et al., Crite
ria for the retention of original seawater 87Sr/86Sr in
ancient shelf limestone, Chem. Geol., 1994, vol. 112,
pp. 131–143.
Derry, L. A., Kaufman, A. J., and Jacosen, S. B., Sedimen
tary cycling and environments change in the Llate Protero
zoic: evidence from stable and radiogenic isotopes,
Geochim. Cosmochim. Acta, 1992, vol. 56, pp. 1317–1329.
Dol’nik, T. A., Stromatolity opornykh razrezov dokembriya
okrainy SayanoBaikal’skoi gornoi oblasti (spravochnoe ruk
ovodstvo) (Stromatolites of Precambrian reference sections
of themargin of the SayanBaikal mountainous area (Refer
ence guide), Irkutsk: Nedra, 1982 [in Russian].
Dol’nik, T. A., Stromatolity i mikrofitolity yuga Sibirskoi
platformy (Stromatolites and microphytolites of the south of
the Siberian Platform), Novosibirsk: Izd. SO RAN, 2000
[in Russian].
Dopolneniya k stratigraficheskomu kodeksu Rossii. Dopol
neniya 4 (Supplements to the Stratigraphic Chart of Russia.
Suppl. 4), St. Petersburg: VSEGEI, 2000 [in Russian].
Fairchild, I. J. and Hambrey, M. J., The Vendian succession
of northeastern Spitsbergen—petrogenesis of a dolomite
Vol. 21
No. 4
2013
380
CHUMAKOV et al.
tillite association, Precambrian Res., 1984, vol. 26, pp. 111–
167.
Fairchild, I. J. and Kennedy, M. J., Neoproterozoic glacia
tion in the earth system, J. Geol. Soc. London, 2007, vol. 164,
pp. 895–921.
Faizullin, M. Sh., New data about Baikalian microfossils of
the Patom Highlands, Geol. Geofiz., 1998, vol. 39, no. 3,
pp. 328–337.
Fedonkin, M. A., Ivantsov, A. Yu., Leonov, M. V., and
Serezhnikova, E. A., Dynamics of evolution and biodiver
sity in the Late Vendian: a view from the White Sea, in The
rise and fall of the Vendian (Ediacaran) biota. Origin of the
modern biosphere. Transact. Int. Conf. on the IGCP project
493, Moscow: GEOS, 2007, pp. 6–9.
Golovenok, V. K., Salop, L. I., and Chumakov, N. M., The
northern part of the Baikal Mountainous Area, in Strati
grafiya SSSR. Verkhnii dokembrii (Startigraphy of the
USSR. Upper Precambrian), Moscow: GNT Izd. Geol.
Okhr. Nedr, 1963, pp. 436–457.
Golubkova, E. Yu., Raevskaya, E. G., and Kuznetsov, A. B.,
Lower Vendian microfossil assemblages of East Siberia: Sig
nificance for solving regional stratigraphic problems of the
region, Stratigr. Geol. Correlation, 2010, vol. 18, no. 4,
pp. 3–27.
Gorokhov, I.M., Semikhatov, M.A., Baskakov, A.V., et al.,
Sr Isotopic Composition in Riphean, Vendian, and Lower
Cambrian in Siberia, Stratigr. Geol. Correlation, 1995, vol. 3,
no. 1, pp. 1–33.
Gosudarstvennaya geologicheskaya karta Rossiiskoi Feder
atsii. Masshtab 1 : 200000. Seriya Bodaibinskaya. List P50
KhKhKhIV (Chapaevo). Ob’’yasnitel’naya zapiska (The
1 : 200000 State Geological Map of the Russian Federation.
Sheet: P50KhKhKhIV (Chapaevo). The explanatory
note), Kokoulin, M.L., Ed., Moscow: Min. Prirodn. Res.
RF, 1998 [in Russian].
Grazhdankin, D. V., Upper Vendian Chronostratigraphy
(on the example of sections of northeastern margin of the
East European Platform and the western slope of the Mid
dle Urals), Extended Abstract of Doctoral (Geolmin) Disser
tation, Novosibirsk: INGT SO RAN, 2011.
Grey, K., Ediacaran palynology of Australia, Mem. Assoc.
Australasian Palaeontologists, 2005, no. 31, p. 439.
Le Guerroue, E., Allen, P.A., and Cozzi, A., Chemostrati
graphic and sedimentological framework of the largest neg
ative carbon isotopic excursion in Earth history: the
Neoproterozoic Shuram Formation (Nafun Group,
Oman), Precambrian Res., 2006, vol. 144, pp. 68–92.
Le Guerroue, E., Duration and synchroneity of the largest
negative carbon isotope excursion on the Earth: the
Shuram/Wonoka anomaly, Comptes Rendus Geosci., 2010,
vol. 342, pp. 204–214.
Halverson, G.H. and ShieldsZhou, G., Chemostratigra
phy and the Neoproterozoic glaciations in The geological record
of Neoproterozoic glaciation, Arnaud, E., Halverson, G.P.,
ShieldsZhou, G., Eds., Mem. Geol. Soc. London, 2011,
vol. 36, pp. 51–66.
Ishikawa, T., Ueno, Y., Komiya, T., et al., Carbon isotope
chemostratigraphy of a Precambrian/Cambrian boundary
section in the Tree Gorge Area, South China: prominent
globalscale isotope excursions just before the Cambrian
explosion, Gondwana Res., 2008, vol. 14, pp. 193–208.
Ivanov, A.I., Lifshits, V.I., Perevalov, T.M., et al., Dokembrii
Patomskogo nagor’ya (Precambrian of the Patom High
lands), Moscow: Nedra, 1995 [in Russian].
Jiang, G. and Kaufman, A.J., ChristieBlick et al., Carbon
isotope variability across the Ediacaran Yangtze Platform in
South China: implications for a large surfacetodeep
ocean δ13C gradient, Earth Planet. Sci. Lett., 2007, vol. 261,
pp. 303–320.
Jiang, G., Shi, X., Zhang, S., et al., Stratigraphy and
palaeogeography of the Ediacaran Doushantuo formation
(ca. 635551 ma) in South China, Gondwana Res., 2011,
vol. 19, pp. 831–849.
Keller, B.M., Semikhatov, M.A., and Chumakov, N.M.,
Stratigrafiya dokembriya i kembriya Srednei Sibiri (Precam
brian and Cambrian Stratigraphy of the Central Siberia),
Krasnoyarsk: Knizhn. Izd., 1967 [in Russian].
Khomentovskii, V.V., Vend (The Vendian), Novosibirsk:
Nauka, 1976 [in Russian].
Khomentovskii, V.V., The Baikalian of Siberia (850–650
Ma), Geol. Geofiz., 2002, vol. 43, no. 4, pp. 313–333.
Khomentovskii, V.V., Postnikov, A. A., and Faizullin, M.
Sh., The Baikalian of Stratotype Area, Geol. Geofiz., 1998,
vol. 39, no. 11, pp. 1505–1517.
Khomentovskii, V.V. and Postnikov, A.A., Neoproterozoic
history of development of the BaikalVilyui Branch of the
Paleoasian Ocean, Geotektonika, 2001, no. 3, pp. 3–21.
Khomentovskii, V.V., Postnikov, A.A., Karlova, G.A., et al.,
The Vendian of the BaikalPatom Highlands (Siberia),
Geol. Geofiz., 2004, vol. 45, pp. 465–484.
Khomentovskii, V.V., Yudomian of Siberia, Vendian and
Ediacaran System in the International Startigraphic Chart,
Stratigr. Geol. Correlation, 2008, vol. 16, no. 6, pp. 3–21.
Knoll, A.H., Grotzinger, J.P., Kaufman, A.J., and Kolo
sov, P.N., Integrated approaches to terminal Proterozoic
stratigraphy: an example from the Olenek Uplift, North
eastern Siberia, Precambrian Res., 1995, vol. 73, nos. 14,
pp. 251–270.
Kochnev, B.B. and Karlova, G.A., New data on biostratig
raphy of the Vendian NemakitDaldynian stage in the
southern Siberian Platform Stratigr. Geol. Correlation, 2010,
vol. 18, no. 5, pp. 28–41.
Kolosov, P.N., Stratigrafiya verkhnego dokembriya yuga
Yakutii (Upper Precambrian stratigraphy of Southern
Yakutia), Novosibirsk: Nauka, 1975 [in Russian].
Kolosov, P.N., Facialgenetic types of organogenic carbon
ate rocks and potential oil and gas collectors in the
Kalanchevo Formation of the Neoproterozoic, Patom oil
and gas area, Otech. Geol., 2010, no. 6, pp. 49–56.
Kolosova, S.P., Late Precambrian spiny microfossils of the
East of the Siberian Platform, Algologiya, 1991, vol. 1, no. 2,
pp. 53–59.
Komar, V.A., Stromatolity verkhnedokembriiskikh otlozhenii
severa Sibirskoi platformy i ikh stratigraficheskoe znachenie
(Upper Precambrian stromatolites in the North of the Sibe
rian Platform and their stratigraphic significance), Mos
cow: Nauka, 1966 [in Russian].
Stratigrafiya neftenosnykh basseinov Sibiri. Rifei i vend Sibir
skoi platformy i ee skladchatogo obramleniya (Stratigraphy of
oilbearing basins of Siberia. Riphean and Vendian of the Sibe
rian Platform and its folded framework), Kontorovich, A.E.,
Ed., Novosibirsk: Geo, 2005 [in Russian].
Krylov, I.N., Stromatolity rifeya i fanerozoya SSSR (rifei i
vend) (Riphean and Phanerozoic stromatolites of the USSR
(Riphean and Vendian)), Moscow: Nauka, 1975 [in Rus
sian].
Kuznetsov A.B., Ovchinnikova G.V., Gorokhov I.M. et al.
Age constraints on the Neoproterozoic Baikal Group from
STRATIGRAPHY AND GEOLOGICAL CORRELATION
Vol. 21
No. 4
2013
VENDIAN REFERENCE SECTION OF SOUTHERN MIDDLE SIBERIA
combined Sr isotopes and PbPb dating of carbonates from the
Baikal type section, southeastern Siberia, J. Asian Earth Sci.,
2012 (in press).
Kuznetsov, A.B. and Letnikova, U.F., The opening of the
Baikalian branch of the Paleoasian Ocean: Sr C isotope
data, in Tektonika zemnoi kory i mantii. Tektonicheskie
zakonomernosti razmeshcheniya poleznykh iskopaemykh.
Materialy soveshchaniya (Tectonics of the Earth’s Crust and
Mantle, Tectonic Regularities of Location of Mineral
Deposits. Proc. Conf.), Moscow: GEOS, 2005, vol. 1,
pp. 352–355.
Kuznetsov, A.B., Semikhatov, M.A., Maslov, A.V., et al., Sr
and SIsotopic Hemostratigraphy of Type Section of the
Upper Riphean (Southern Ural): new data, Stratigr. Geol.
Correaltion, 2006, vol. 14, no. 6, pp. 25–53.
Leather, J., Allen, P.A., Brasier, M.D., and Cozzi, A.,
Neoproterozoic snowball earth under scrutiny: evidence
from the Fiq glaciation of Oman, Geology, 2002, vol. 30,
pp. 891–894.
Leonov, M.V. and Rud’ko, S.V., Finding of the Ediacaran
Vendian fossils in the Far Taiga Deposits, Patom highlands,
Stratigr. Geol. Correlation, 2012, vol. 20, no. 5, pp. 96–99.
Lungersgauzen, G.F., Tillites and tillitelike formations, in
Stratigrafiya SSSR. Verkhnii dokembrii (Stratigraphy of the
USSR. Upper Precambrian), Moscow: Nedra, 1963,
pp. 566–577.
McFadden, K.A., Xiao, S., Zhou, Ch., and Kowalewskii,
M., Quantitative evaluation of the biostratigraphic distribu
tion of acanthomorphic acritarchs in the Ediacaran Doush
antuo Formation in the Yangtze Gorges Area, South China,
Precambrian Res., 2009, vol. 173, pp. 170–190.
Meffre, S., Large, R.R., Scott, R., et al., Age and pyrite Pb
isotopic composition of the giant Sukhoi Log sediments
hosted gold deposits, Russia, Geochim. Cosmochim. Acta,
2008, vol. 72, no. 9, pp. 697–715.
Melezhik, V.A., Pokrovsky, B.G., Fallick, A.E., et al., Con
straints on 87Sr/86Sr of Late Ediacaran seawater: insight
from Siberian highSr limestones, J. Geol. Soc. London,
2009, vol. 166, pp. 183–191.
Moczydlowska, M., Taxonomic review of some Ediacarian
acritarchs from the Siberian Platform, Precambrian Res.,
2005, vol. 136, pp. 283–307.
Moczydlowska, M. and Nagovitsin, K., Eriacaran radiation
of organicwalled microbiota recorded in the Ura forma
tion, Patom Uplift, East Siberia, Precambrian Res., 2012,
vol. 198–199, pp. 1–24.
Nagovitsin, K.E., Faizullin, M.Sh., and Yakshin, M.S.,
New forms of acanthomorphic acritarchs of Baikalian of
Patom Upland (Ura Formation, East Siberia) in News of
Paleontology and Stratigraphy. Suppl. to Geol. Geophys, 2004,
vol. 45, nos. 6–7, pp. 7–19.
Obruchev, V.A., The Precambrian of Siberia, in Strati
grafiya SSSR. T. 1 (Stratigraphy of the USSR. Vol. 1), Mos
cow: Izd. AN SSSR, 1939 [in Russian].
Opornye razrezy otlozhenii verkhnego dokembriya Sibirskoi
platformy (Reference sections of Upper Precambrian
deposits of the Siberian Platfrom), Moscow: Nauka, 1972
[in Russian].
Pelechaty, S.M., Integrated chronostratigraphy of the Ven
dian System of Siberia: implication for a global stratigraphy,
J. Geol. Soc. London, 1998, vol. 155, pp. 957–973.
Petrov, A.F., Stratigraphy and correlation of Late Precam
brian deposits of the southwestern part of the Aldan Antec
lise and its frame, in Materialy Po geologii i poleznym isko
STRATIGRAPHY AND GEOLOGICAL CORRELATION
381
paemym YaASSR,(Materials on geology and mineral
resources of the YaASSR), 1966, no. 15, pp. 33–43.
Pokrovskii, B.G., Melezhik, V.A., and Buyakaite, M.I.,
Carbon, Oxygen, Strontium, and Sulfur Isotopic Composi
tions in Late Precambrian Rocks of the Patom Complex.
Central Siberia. Rep. 1. Results, isotope stratigraphy and
age dating problems, Litol. Polezn. Iskop., 2006, no. 5,
pp. 505–530.
Pokrovskii, B.G., Chumakov, N.M., Melezhik, V.A., and
Buyakaite, M.I., Geochemical features and problems of
genesis of Neoproterozoic “overlying dolomites” of the
Patom paleobasin, Litol. Polezn. Iskop., 2010, no. 6,
pp. 644–651.
Resheniya Mezhvedomstvennogo soveshchaniya po razrabo
tke unifitsirovannykh stratigraficheskikh skhem Yakutskoi
ASSR, 1961 g (Resolution of the interdepartmental regional
stratigraphical conference on the elaboration of the unified
stratigraphical schemes for Yakutsk YaSSR), Moscow: Gos
geoltekhizdat, 1963 [in Russian].
Rieu, R., Allen, P.A., Cozzi, A., et al., A composite stratig
raphy for the Neoproterozoic Huqf Supergroup of Oman:
integrating new litho, chemo and chronostratigraphic
data of the Mirbat Area, Southern Oman, J. Geol. Soc. Lon
don, 2007, vol. 164, pp. 997–1009.
Semikhatov, M.A., Komar, Vl.A., and Serebryakov, S.N.,
Yudomskii kompleks stratotipicheskoi mestnosti (The Yudo
mian complex of stratotype area), Moscow: Nauka, 1970
[in Russian].
Semikhatov, M.A. and Serebryakov, S.N., Sibirskii gipostra
totip rifeya (The Riphean hypostratotype in Siberia), Mos
cow: Nauka, 1983 [in Russian].
Semikhatov, M.A., Stromatolites in the Precambrian
Stratigraphy: analysis 84, Izv. Akad. Nauk SSSR, Ser. Geol.,
1985, no. 4, pp. 3–21.
Semikhatov, M.A., Kuznetsov, A.B., Podkovyrov, V.N.,
et al., The Yudomian complex of stratotype area: Cisotope
hemostratigraphic correlations and YudomianVendian
relation, Stratigr. Geol. Correlation, 2004, vol. 12, no. 5,
pp. 3–28.
Sergeev, V.N., Semikhatov, M.A., Fedonkin, M.A., and
Vorob’eva, N.G., Principal stages in evolution of Precam
brian organic world: communication 2. Late Proterozoic,
Stratigr. Geol. Correlation, 2010, vol. 18, no. 6, pp. 3–33.
Sergeev, V.N., Knoll, A.H., and Vorob’eva, N.G., Ediaca
ran microfossils from the Ura Formation, BaikalPatom
Uplift, Siberia: taxonomy and biostratigraphic significance,
J. Paleontol., 2011, vol. 85, no. 5, pp. 987–1011.
Sokolov, B.S., Chronostratigraphic space of the Lithos
phere, and the Vendian as a geohistorical subdivision of the
Neoproterozoic, Proc. Conf. on Neoproterozoic sedimentary
basins, Grazhdankin D.V., Marusin, V. V., Eds., Novosi
birsk, 2011, pp. 4–5.
Sokolov, B.S., Ocherki stanovleniya venda (Essays on the
Advent of the Vendian System), Moscow: KMK Ltd, 1997
[in Russian].
Sokolov, B.S., Paleontology of the Precambrian and acro
chrones of biosphere evolution. (on the theory of expanding
biosphere), Stratigr. Geol. Correlation, 2012, vol. 20, no. 2,
pp. 3–12.
Sovetov, J.K., Vendian Foreland basin of the Siberian cra
tonic margin: Paleopangean accretionary phases, Rus. J.
Earth Sci., 2002, vol. 4, pp. 363–387.
Sovetov, Yu.K. and Komlev, D.A., Tillites at the base of the
Oselok Group, foothills of the Sayan Mountains, and the
Vendian lower boundary in the southwestern part of
Vol. 21
No. 4
2013
382
CHUMAKOV et al.
the Siberian Platform Sibirskoi platformy, Stratigr. Geol.
Correaltion, 2005, vol. 13, no. 4, pp. 3–34.
Stanevich, A.M., Nemirov, V.K., and Chatta, E.N., Mikro
fossilii proterozoya SayanoBaikal’skoi skladchatoi oblasti
(Proterozoic microfossils of the SayanBaikal Folded
Area), Novosibirsk: Akad. Izd. GEO, 2006 [in Russian].
Stanevich, A.M., Mazukabzov, A.M., Postnikov, A.A.,
et al., Northern segment of the Paleoasian Ocean: Neopro
terozoic deposition history and geodynamics, Geol. Geofiz.,
2007, vol. 48, no. 1, pp. 60–79.
Starostina, Z.M., Geological structure of the northern mar
gin of the Patom Highlands and adjacent part of the Lena
peneplain, Byull. Mosk. Ova Ispyt. Prir., Otd. Geol., 1935,
vol. 13, no. 3, pp. 305–349.
Steiner, M., Li, G., Zhu, M., and Erdtmann, B.D.,
Neoproterozoic to Early Cambrian small shelly fossil
assemblages and revised biostratigraphic correlation of the
Yangtze Platform (China), Palaeogeogr. Palaeoclim. Palaeo
ecol., 2007, vol. 254, pp. 67–99.
Veis, A.F., Vorob’eva, N.G., and Golubkova, E.Yu., The
early Vendian microfossils first found in the Russian plate:
Taxonomic composition and biostratigraphic significance,
Stratigr. Geol. Correlation, 1996, vol. 14, no. 4, pp. 368–385.
Vorob’eva, N.G., Sergeev, V.N., and Semikhatov, M.A.,
Unique lower Vendian Kel’tma microbiota, Timan ridge:
New evidence for the paleontological essence and global
significance of the Vendian System, Dokl. Akad. Nauk,
2006, vol. 410, no. 3, pp. 366–371.
Vorob’eva, N.G., Sergeev, V.N., and Knoll, A.H., Micro
fossil assemblages from the Vychegda Formation of the East
European Platform passive margin a biostratigraphic
model for the Upper Riphean (Crygenian)/Vendian (Edi
acaran) boundary, in Rassvet i zakat vendskoi (ediakarskoi)
bioty. Proiskhozhdenie sovremennoi biosfery. Trudy Mezh
dunarodnoi konferentsii po proektu, p. 493 (The sunrise and
sunset of Vendian (Ediacarian) Biota. Origin of modern
biosphere. Proc. Int. Conf. Project 493MPGK), Moscow:
GEOS, 2007, pp. 42–46.
Vorob’eva, N.G., Sergeev, V.N., and Knoll, A.H., Lower
Vendian Phytoplankton and Zooproblematics of the East
European Platform (Timan Ridge)—Biostratigraphic
model of the lower boundary of the Proterozoic terminal
system, in Sbornik trudov XII Vserossiiskoi palinologicheskoi
konferentsii. Palinologiya: stratigrafiya i geoekologiya (Proc.
XII AllRus. Plynol. Conf. Palynology: stratigraphy and
geoecology), Irkutsk, 2008, vol. III, pp. 7–12.
Vorob’eva, N.G., Sergeev, V.N., and Chumakov, N.M.,
New finds of Early Vendian microfossils in the Ura Forma
tion: revision of the age of the Patom Complex of the Cen
tral Siberia, Dokl. Akad. Nauk, 2008a, vol. 419, no. 6,
pp. 782–787.
Vorob’eva, N.G., Sergeev, V.N., and Knoll, A.H., Neopro
terozoic microfossils from the northeastern margin of the
East European Platform, J. Paleontol., 2009a, vol. 83, no. 2,
pp. 161–196.
Vorob’eva, N.G., Sergeev, V.N., and Knoll, A.H., Neopro
terozoic microfossils from the margin of the East European
Platform and the search for a biostratigraphic model of
Lower Ediacaran rocks, Precambrian Res., 2009b, vol. 173,
nos. 14, pp. 163–169.
Walter, M.R., Veevers, J.J., Calver, C.R., et al., Dating the
840544 Ma Neoproterozoic interval by isotopes of stron
tium, carbon, and sulfur in seawater, and some interpreta
tive models, Precambrian Res., 2000, vol. 100, pp. 371–433.
Yakshin, M.S., Algal microfossils from the Vendian key sec
tion of the Patom Highlands, Geol. Geofiz., 2002, vol. 43,
no. 5, pp. 12–31 (Supplement)
Gosudarstvennaya geologicheskaya karta Rossiiskoi Feder
atsii. Masshtab 1 : 200000. Seriya Bodaibinskaya. List P50
KhKhKhIII (Nyuya). Ob’’yasnitel’naya zapiska (The
1 : 200000 State Geological Map of the Russian Federation.
The Bodaibo Series. Sheet: P50KhKhKhIII (Nyunya).
The explanatory note), Zamaraev, S.M., Ed., Moscow:
Min. Geol. SSSR, 1984 [in Russian].
Zhang, S., Jiang, G., Zhang, J., et al., UPb sensitive high
resolution ion microprobe age from the Doushantuo For
mation in South China: constraints on Late Neoprotero
zoic glaciation, Geology, 2005, vol. 33, pp. 473–476.
Zhang, Q.R., Chu, X.L., and Feng, L.J., Neoprotero
zoic glacial records in the Yangtze Region, China, in The
Geological Record of Neoproterozoic glaciations, Arnaud, E.,
Halverson, G.P., and ShieldsZhou, G., Eds., Mem. Geol.
Soc. London, 2011, no. 36, pp. 357–366.
Zhou, C., Xiao, S., Hong, H., et al., Carbon isotope
chemostratigraphy and biostratigraphy of the Ediacaran
system in South China, Proc. Conf. on Neoproterozoic sedi
mentary basins, Grazhdankin D.V., Marusin, V. V., Eds.,
Novosibirsk, 2011, pp. 112–113.
Zhou, C. and Xiao, S., Ediacaran δ13C chemostratigraphy
of South China, Chem. Geol., 2007, vol. 89, pp. 89–108.
Zhou, C., Xie, G., McFadden, K., et al., The diversification
and extinction of DoushantuoPertatataka acritarchs in
South China: causes and biostratigraphic significance,
Geol. J., 2007, vol. 42, no. 2, pp. 229–262.
Zhu, M., Strauss, H., and Shields, G.A., From snowball
earth to the Cambrian bioradiation: calibration of Ediacaran
Cambrian Earth history of South China, Palaeogeogr. Palaeo
clim. Palaeoecol., 2007b, vol. 254, nos. 1–2, pp. 7–61.
Zhu, M., Zhang, J., and Yang, A., Integrated Ediacaran
(Sinian) chronostratigraphy of South China, Palaeogeogr.
Palaeoclimat. Palaeoecol., 2007b, vol. 254, nos. 1–2, pp. 7–61.
Zhuravleva, Z.A., Komar, V.A., and Chumakov, N.M.,
Stratigraphic relations between the Patom Complex and
sedimentary formations of the western and northern slopes
of the Aldan Shield, Dokl. Akad. Nauk SSSR, 1959, vol. 12,
no. 5, pp. 1026–1029.
Zhuravleva, Z.A., Komar, V.A., and Chumakov, N.M.,
Structure and correlation of Upper Precambrian depsoits of
western Yakutia in Mezhvedomstvennoe Soveshchanie po
razrabotke unifitsirovannykh stratigraficheskikh skhem
Yakutskoi ASSR, (Proc. Interdepart. Regional Stratigr.
Conf. on the Elaboration of the Unified Stratigr. Schemes
for Yakutsk YaSSR) 1961, pp. 9–11.
Zhuravleva, Z.A. and Komar, V.A., The Riphean (Sinian)
stratigraphy of the Anabar massif, Dokl. Akad. Nauk SSSR,
1962, vol. 144, no. 1, pp. 188–207.
Zhuravleva, Z.A., Komar, V.A., and Chumakov, N.M.,
Stroenie i korrelyatsiya verkhnedokembriiskikh otlozhenii
zapadnoi Yakutii in Trudy Mezhvedomstvennogo sovesh
chaniya po razrabotke unifitsirovannykh stratigraficheskikh
skhem Yakutskoi ASSR, Materialy Po geologii i poleznym
iskopaemym Yakutskoi ASSR (Proc. Interdepart. Regional
Stratigr. Conf. on the Elaboration of the Unified Stratigr.
Schemes for Yakutsk YaSSR)1969, no. 13, pp. 53–69.
STRATIGRAPHY AND GEOLOGICAL CORRELATION
SPELL: 1. cherts
Translated by I. Basov
Vol. 21
No. 4
2013