Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227 – 244
www.elsevier.com/locate/palaeo
δ 13 C records across the late Silurian Lau event: New data from
middle palaeo-latitudes of northern peri-Gondwana
(Prague Basin, Czech Republic)
Oliver Lehnert a,⁎, Jiři Frýda b , Werner Buggisch a , Axel Munnecke c ,
Alexander Nützel c , Jiři Křiž b , Stepan Manda b
a
Universität Erlangen, Institut für Geologie und Mineralogie, Schlossgarten 5, D-91054 Erlangen, Germany
b
Czech Geological Survey, Klárov 3/131, 118 21 Prague 1, Czech Republic
c
Universität Erlangen, Institut für Paläontologie, Loewenichstr. 28, D-91054 Erlangen, Germany
Received 29 March 2005; accepted 2 February 2006
Abstract
During the late Silurian the Prague Basin was located in middle southern latitudes. In contrast to palaeocontinents positioned in
tropical and subtropical latitudes like Baltica, no reefs are developed, which is in accordance with the predicted cooler water. The
Prague Basin represents a relatively restricted and shallow rift basin with a complex tectonic history. Sections in different
palaeoenvironments have been studied to document the most prominent Silurian stable carbon isotope excursion recorded during
the late Silurian (Ludfordian) Lau Event from this part of peri-Gondwana. Deeper water deposits of the Kopanina Formation
investigated in the present study were deposited on the slope-to-basin transition near the Kosov volcanic centre in the western part
of Prague Basin. The sediments are developed as an alternation of dark, partly laminated limestones and marls with an increase of
the limestone–marl ratio in the upper part of the succession. A pronounced positive carbon isotope excursion starts in the
Neocullograptus kozlowskii graptolite and in the upper Polygnathoides siluricus conodont zone. The maximum of the shift is
observed in the lower part of an interval characterised by the Ananaspis fecunda–Cyrthia postera community. The maximum
values scatter around 8‰, which represent the highest values reported hitherto from the Prague Basin. In low latitudes, often a
decrease of δ13C values towards deeper water settings is reported. In contrast, in the present study the δ13C values of about 8‰ are
much higher than those recorded from the contemporaneous shallow-water sections studied in the classical Mušlovka and Požáry
quarries. The most reasonable explanation is the presence of stratigraphical gaps in the shallow parts of the basin. As indicated by
karstification these gaps were caused by a sea-level drop. Another effect of this sea-level fall was a strongly reduced sedimentation
of the cephalopod limestone facies around volcanic and tectonic elevations.
© 2006 Elsevier B.V. All rights reserved.
Keywords: Silurian; Ludlow; Lau Event; Stable isotopes; Prague Basin; Peri-Gondwana
1. Introduction
⁎ Corresponding author. Tel.: +49 9131 8522632; fax: +49 9131
8529295.
E-mail address: [email protected] (O. Lehnert).
0031-0182/$ - see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.palaeo.2006.02.022
Based on recent investigations of stable isotopes in
close connection to research on faunal extinctions, the
Silurian turns out to be more and more of interest for
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O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
Fig. 1. Palaeogeographical distribution for published records of the late Silurian (Ludfordian) stable carbon isotope excursion (palaeogeographic
reconstruction after Scotese and McKerrow, 1990). Note that most locations shown represent more than one report and a number of sections. (1)
Laurentia, Nevada and Oklahoma (Saltzman, 2001), (2) Baltica, Sweden (Jux and Steuber, 1992; Samtleben et al., 1996; Wenzel and Joachimski,
1996; Bickert et al., 1997; Azmy et al., 1998; Wigforss-Lange, 1999; Samtleben et al., 2000; Calner and Eriksson, 2006), (3) Baltica, eastern Baltic
(Kaljo et al., 1997, 1998; Modzalevskaya and Wenzel, 1999; Martma et al., 2005), (4) Australia, Queensland (Andrew et al., 1994), (5) Bohemia
(Lehnert et al., 2003; this study).
general studies on changes in climate, environments, and
their biota (e.g., Jeppsson, 1984, 1987, 1990; Kaljo et al.,
1995, 1997; Jeppsson, 1997, 1998; Kaljo et al., 1998;
Jeppsson and Aldridge, 2000; Saltzman, 2001; Munnecke et al., 2003; Calner, 2005b; Stricanne et al., 2006).
This paper focuses on a prominent late Silurian
Fig. 2. Geographic distribution of the Silurian exposures in the Prague Basin with the position of sampled locations and areas mentioned in the text;
(1) Kosov Quarry (Dlouha Hora), (2) The Mušlovka Quarry and Požáry Quarry area, (3) The Marble Quarry and Cephalopod Quarry area (modified
from a file which was kindly provided by R. Moravek, Charles University, Prague); for detailed geographic positions see coordinates in the text and
illustrations by Kříž, 1992).
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
229
forward (e.g. Jeppsson, 1990; Bickert et al., 1997;
Jeppsson, 1998; Cramer and Saltzman, 2005).
The aim of the present study is (a) to present δ13C data
from a palaeogeographic position between Baltica and
northern Gondwana, (b) to compare contemporaneous
δ 13 C signals from shallow-water and deeper-water
settings in the Prague Basin, and, (c) to compare the
palaeontological and sedimentological characteristics of
this time interval at relatively high latitudes with those
previously reported from low palaeolatitudes.
2. The Silurian of the Prague Basin
Fig. 3. Stratigraphical chart of the Silurian succession exposed in the
structurally complicated Kosov Quarry. The stratigraphical position of
the interval sampled for stable carbon isotopes is indicated by a grey
bar.
(Ludfordian) event, and presents new data from different
palaeoenvironments of the Prague Basin. The late
Silurian positive δ13C excursion has been recognised
globally (Fig. 1; Martma et al., 2005, and references
therein) and represents the strongest carbon isotope
excursion of the whole Phanerozoic (Munnecke et al.,
2003) reaching extremely high values up to 12‰ in
Australia (Andrew et al., 1994; Figs. 1–4) and 11.2‰ in
southern Sweden (Wigforss-Lange, 1999; Figs. 1–2).
The excursion has also been recorded from eastern
Baltica (Figs. 1–3; Martma et al., 2005, and references
therein), from Laurentia (Saltzman, 2001, Fig. 1-1), and
from Bohemia (Lehnert et al., 2003; Figs. 1–6). The
lower part of the excursion, i.e. the part with increasing
δ13C values, corresponds to a time period with faunal
changes, termed “Lau Event” (named after the village of
Lau on Gotland, Sweden; Jeppsson, 1993).
Several positive δ13C excursions are recorded from
the Early Palaeozoic. These show strikingly similar
geochemical, palaeontological, and sedimentological
characteristics and therefore indicate common steering
mechanisms (Munnecke et al., 2003). Changes between
humid and arid climates in lower latitudes have been
proposed as causing the anomalies by several authors,
and different palaeoceanographic models have been put
Since Joachim Barrande, palaeontologists have been
working on the Early Palaeozoic succession for more
than 200 years in this classical geological area of Central
Europe (references in Kříž, 1998a). Major steps in
improving the knowledge of the regional Silurian
geology were made during the last century by Horný
(1955a, b, 1960) who provided the first maps displaying
the facies distribution in the basin, which later have been
continuously modified and improved by Kříž (references
in Kříž et al., 2003). The geological history of the Prague
Basin during the Silurian and references to all important
studies were compiled by Kříž (1991, 1992, 1998a,b).
In the Prague Basin, which during the Silurian was
located in northern peri-Gondwana, there is a general
shift from siliciclastic to tropical carbonate deposition
from the Ordovician to the Devonian. Two main factors
are responsible for this change: First, the drift of the
Prague Basin into lower latitudes and, secondly, the
increasingly warmer climates following the Late
Ordovician and earliest Silurian glaciations (Grahn
and Caputo, 1992; Caputo, 1998; Díaz-Martínez et al.,
2001). According to Krs et al. (1986) the Prague Basin
was located between 20 to 30° S during Ordovician
times, and around 5 to 9° S during the early Devonian.
In their reconstructions, Tait et al. (1995) place it in
slightly higher palaeolatitudes.
The Prague Basin fill is biostratigraphically well
dated (Kříž, 1992, 1998b), and 41 graptolite zones were
established in the Silurian of Bohemia (35 by Štorch,
1994, 1995 for the Llandovery–Ludlow; 6 by Jaeger in
Kříž et al., 1986 for the Přídolí).
In the Silurian, the Prague Basin was characterised
by an active fault system (Kříž, 1991) leading to the
development of rapid lateral facies changes over short
distances. Relatively intense volcanism along and at the
intersections of these major faults is another typical
feature of the basin (Kříž, 1991), and the interaction of
this volcanism with sedimentation in different areas of
the basin was first pointed out by Horný (1955a). The
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Fig. 4. Kosov Section with δ13C record across the critical interval; numbers on the left side of the column correspond to limestone beds; bar to the left
indicates the interval with numbers in the section painted by Kříž and Manda.
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
231
Fig. 5. The sampled section of the upper Kopanina Formation on level 2 in the southern part of the Kosov Quarry. (A) View to the south with deeper
water shales at base of the section to the lower right and the top of the section to the left (a person for scale on the lower left side). Amc =
Acantholomina minuta community, mac = monospecific atrypid community. (B) The boundary between tuffitic shales and marls with intercalated
limestone lenses, and overlying bioclastic limestones (beds 13 and up). Note that the increase to high δ13C starts within the lowermost continuous
limestone horizon (bed 13), yielding the last faunas of the Ch. glabra community (Cgc), and rises to values between 6 and 8‰ in the overlying strata.
The LAD level of N. kozlowskii is indicated by a stippled line. (C) Bioclastic limestones with few marl intercalations in the upper sampled interval
with high δ13C values (beds 23–30). White scale bars = 0.5 m.
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O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
facies distribution throughout the Prague Basin is rather
complex and the general picture supported by biostratigraphic data has been compiled by Kříž (1991).
233
standards and was better than ± 0.1‰ for both carbon
and oxygen isotopes.
4. The Kosov Quarry section
3. Sampling and methods
4.1. Local geological framework
Carbonates within the Upper Silurian Kopanina
Formation were sampled in different parts and palaeoenvironments of the Prague Basin in order to investigate the
carbon isotope record in sections including the Ludfordian Lau Event. In addition to an important section in the
western part of the Prague Basin near the Kosov Volcanic
Center (40 analysed samples), two other sections,
representing more shallow-water environments, in the
vicinity of Prague are described (Fig. 2). There, the
Mušlovka Quarry (80 samples) and the Požáry Quarry
sections (58 samples; GSSP, Global Stratotype Section
and Point for the base of the Přídolí; Kříž et al., 1986)
have been sampled across the Lau Event interval, and the
material was analysed for carbon isotope studies.
Because the limestone successions in two other sections
in the Cephalopod Quarry and the Marble Quarry (Fig. 2/
3) reveal a strong diagenetic overprint and is too
condensed, only the datasets from the Mušlovka Quarry
and the Požáry Quarry sections are described and
discussed in this study. All δ13C sampling was related
to the numbers of beds by Kříž (1992) in published and
painted sections of the Mušlovka and Požáry quarries,
and to new numbers in the section at Kosov. In addition
to the carbon isotope analysis thin sections have been
studied from the different lithologies for additional facies
informations.
A few milligrams of rock powder (preferably micrite)
were recovered with a dental drill from cut and polished
slabs. If possible, mudstones and wackestones were
sampled, but analyses were also done on grainstones.
The carbonate powder was reacted with phosphoric acid
in an on-line carbonate preparation system (Carbo-Kiel)
connected to a ThermoFinnigan 252 mass spectrometer.
All values are reported in ‰ relative to V-PDB by
assigning a δ13C value of + 1.95‰ and a δ18O value of
2.20‰ to NSB 19. Accuracy and precision was
controlled by replicate measurements of laboratory
The geology of this classical area is structurally very
complicated. Many sections of the large Kosov quarry
area (Dlouha Hora) were studied in detail (Horný,
1955b; Havlíček et al., 1958; Turek, 1983; Kříž et al.,
1986; Turek, 1990; Kříž, 1992; Štorch, 1995; Čáp et al.,
2003). The faunal communities of the sections were
described by Chlupáč (1987), Havlíček and Štorch
(1990), and Kříž (1999). The Ludlow sections exposed
in the quarry reveal different depositional environments
between deeper water shales to the SW and shallow
water deposits close to the Kosov volcanic centre (Kříž,
1992). These drastic lateral facies changes between the
sections exposed within the Kosov Quarry have been
discussed by Bouček (1937), Horný (1955a), Havlíček
et al. (1958), and Kříž (1992).
Kříž (1998b) provides a description and a compiled
stratigraphic chart for the Silurian succession in
structurally complicated, larger Kosov area. At the
Kosov Quarry, a key location for this study, the Silurian
succession starts with finely laminated, anoxic black
shales of the Motol Formation (Fig. 3; mid-Sheinwoodian belophorus Zone; Turek, 1990), which are intruded
by subhorizontal basalt sills. The succession continues
with volcanoclastic deposits reflecting strong volcanic
activity in the middle Silurian. The deposition of the
Kopanina Formation (Fig. 3) started already in the
earliest Gorstian (Lower Ludlow). During the latest
Gorstian a decrease in volcanic activity took place
throughout the basin (Fiala, 1982; Štorch, 1998).
However, during the P. siluricus conodont chron there
was at least one major volcanic event, as indicated by
deposition of tuffites over large parts of the basin (Kříž,
1992). The Ludfordian (Upper Ludlow) strata of the
basin are characterised by a widespread distribution of
cephalopod limestone (Ferretti and Kříž, 1995). The
Ludfordian deposits of the upper Kopanina Formation
Fig. 6. Micrographs from the sampled succession exposed in the southern part of Kosov Quarry. (A) Laminated wackestone with darker (organic-rich)
and lighter portions showing some variation in grain size, sample BO 408, bed 5. (B) Wackestone with small bioclasts: sponge spicules, trilobite
cuticles and echinoderm fragments, sample BO 481, bed 35. (C) Wackestone with triaxon megasclere, sample BO 446, bed 19. (D) Spiculitic
wackestone layer; large sponge spicule with distinct central canal on lower part image; most of circular objects are transverse section of sponge
spicules; samples BO 408, bed 5. (E) Wackestone with small clasts (lower part) covered by a packstone layer formed by thin bioclasts (mostly trilobite
cuticles), sample BO 465, lower 8 cm of interval between beds 27 and 28. (F) Crinoidal packstone with interbedded wackestone facies; crinoids are
mainly represented by disarticulated columnalia, sample BO 436, lower part of bed 16. (G) Wackestone layer, trilobite cuticles floating in
microsparitic matrix, sample BO 408, bed 5. (H) Bioclastic packstone with a tabulate coral (heliolitid), sample BO 436, lower part of bed 16. Scale
bars = 0.5 mm (except for 1, where the scale bar is 1.0 cm).
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in Kosov quarry reveal different limestone facies, and
are covered by Přídolian shales and limestones of the
Požáry Formation (Fig. 3).
The section sampled for stable isotopes (49° 56′ 22.0″
N, 14° 03′ 16.2″ E) is located close to the top of Dlouhá
Hora (Kosov Hill), about 2.5 km southwest of the Beroun
railway station, between sections 783 and 418B of Kříž
(1992, Fig. 38), on level 2 in the southern part of the
Kosov quarry area. It represents an, for this area,
exceptional setting, reflecting a deeper water setting on
the lower slope to basin transition of the Kosov volcanic
complex, and relatively close to its center. In contrast to
the complete sedimentary record in this location, the
shallow-water sections closer to the volcanic center show
stratigraphical gaps in the critical interval. Conodont
samples (2 to 5 kg) have been taken in the section, but they
were not very productive. Only one sample from bed 10
(Fig. 4) yielded P. siluricus, the index taxon of the P.
siluricus Conodont Zone. Most samples above the LAD
of N. kozlowskii were even barren or yielded just a few
long-ranging elements. Larger samples have to be
processed for establishing a zonation in this section.
Štorch (1995) described graptolite assemblages of the N.
inexpectatus und N. kozlowskii Graptolite Zones from the
sampled section, and gave a detailed description of the
lithological succession. In the upper part of his graptolitebearing interval we observe increasing δ13C values.
Unfortunately, the peak interval is not completely
recorded in the studied section (Figs. 4 and 5) because
of a fault, cutting off the upper part of the succession.
4.2. Faunal succession and depositional environment
Our studied section starts approximately 2 m above
the massive shallow-water limestone horizons of the
Cromus beaumonti Assemblage zone yielding the
Atrypoidea lingulata brachiopod community. The
upper part of these Atrypoidea lingulata beds containing
abundant specimens of the brachiopods Dayia minor
and Septatrypa thisbe. The lowermost samples were
taken in a 7 m thick unit of rhythmically alternating
brown-grey calcareous shales with nodules and lenses of
micritic mud- and wackestone indicating a sudden
increase of depositional depth in this particular location.
Here typical faunal elements of the low-diverse Diacanthaspis (Acanthalomina) minuta community are
present. The section (Figs. 4, 5A), painted and measured
2004 by Kříž and Manda before the stable isotope
sampling, starts with bed no. 1 about 3 m below the last
occurrence of this Diacanthaspis (Acanthalomina)
minuta assemblage. This community “consists chiefly
of vagrant benthos; presence of complete exoskeletons
of Acantholomina minuta (Barr.) and Ontarion difractum Zenk. indicates a quiet, deeper-water environment”
(Havlíček and Štorch, 1990, p. 37). The Acantholomina
community (Fig. 4) is interpreted as one of deepest
faunal communities within the whole basin (Havlíček
and Štorch, 1990, Fig. 5). This rhythmically bedded
limestone–shale unit yields graptolites of the inexpectatus and kozlowskii Graptolite Zones (Štorch, 1995).
The boundary between the inexpectatus and kozlowskii
Graptolite Zones is approximately 1.5 m below the
painted section illustrated on Fig. 4 (Štorch, 1995).
The highest beds of the Acantholomina community
are composed by micritic limestone (individual beds
approx. 0.25 m thick) yielding taxa of the Cheiropteria
glabra community (Kříž, 1999). The Cheiropteria
glabra community occurs typically in deeper and less
oxygenated environments (Kříž et al., 2003). Within
these horizons the last occurrence of N. kozlowskii and
Bohemograptus bohemicus tenuis was observed.
A sudden change from these beds to the overlying
thicker-bedded micritic limestones with only few and
thin shaly intercalations indicates a relative shallowing
of the depositional environment. Here taxa of the typical
Kosovopelthis–Scharyia–Metaplasia community are
present, before the diverse faunas of the Ananaspis
fecunda–Cyrthia postera community (Havlíček and
Štorch, 1990) appear in the highest part of the sampled
section. The latter are characterised by an immigration
of new faunal elements to the Prague Basin, e.g.
trilobites, cephalopods, and brachiopods. This faunal
overturn occurs in the interval of maximum δ13C values
in the Mušlovka section (Lehnert et al., 2003).
In sections of the northeastern part of the Kosov
Quarry, above the interval with Ananaspis fecunda–
Cyrthia postera, a relative shallowing is observed in the
uppermost Kopanina Formation. There, an approximately 5 m thick light massive biodetritic nautiloid limestone
of the Prionopeltis archiaci Trilobite Assemblage Zone
crops out. The limestone includes many different benthic
groups, e.g. brachiopods, trilobites, and gastropods (Kříž
et al., 1986). The sharp boundary between the massive
bioclastic limestone of the Kopanina Formation. and the
overlying shaly beds of the Požáry Formation, which are
exposed also in this part of the quarry, indicates a hiatus
(Kříž et al., 1986; Čáp et al., 2003).
4.3. Isotope record and microfacies
In the studied section of the upper Kopanina
Formation, on level 2 in the southern part of Kosov
Quarry, a positive shift in δ13C values during the Lau
Event interval is observed (Figs. 4, 5). The microfacies
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
studies of selected lithologies (17 thin sections) from
various levels reflect the general shallowing upward
trend within the succession composed by limestone marl
alternations with less clastic input towards the top, and
thus, confirming the published data on the environmental interpretation of macrofaunal assemblages (Kříž,
1992).
The lower part of the section (Figs. 4, 5B, C) is
composed of deep water shales, tuffitic shales, and black
spiculitic mud- to wackestone (Fig. 6A, C, F) deposited
in a lower slope to basin environment. They are
interrupted by some small scale debris flows, slumping
structures and turbitites. Graded bedding is visible in
these turbititic layers, which also contain a high amount
of allochthonous crinoidal fragments (Fig. 6F, B)
transported downslope from the near-by shallow
environments that existed around the Kosov Volcanic
Centre.
In general, isolated crinoid columnalia, thin shells
(mostly trilobite cuticles) and hexactinellid megascleres
(triaxon and monaxon; Fig. 6C, D) are the dominant
bioclasts in the autochthonous, lenticular black limestones beds in the lower part of the section. Thin trilobite
cuticles (Fig. 6G) are commonly enriched in distinct
layers forming trilobite packstones. Fine lamination
(Fig. 6A) and an obviously high content of organic
matter might suggest some anoxic pore water after
deposition and eventually deposition in a basin under
anoxic conditions. The dominance of thin trilobite
cuticles in some layers indicates an offshore environment (Fortey and Wilmot, 1991) and many of the
bioclasts (sponge spicules, Fig. 6C, D; trilobite cuticles,
Fig. 6G) probably derive from an open marine,
relatively deep water setting. However, in this deep
water setting close to the active volcanic center, material
was transported from the shallow-water environments at
the volcanic complex. The number of turbititic or
tempestitic layers (coarse grained beds with abundant
crinoid columnalia) increases towards the top of the
predominantly shaly and marly unit.
Carbon isotope sampling started in this lower unit
7.2 m below the base of the painted section and δ13C
values of the corresponding 15 samples (not shown in
Fig. 4) scatter between + 0.4‰ and − 1.3‰ except one
sample with an value of +2.4‰ 0.8 m below base of the
stratigraphic column shown in Fig. 4. This pattern
continues up to the top of the lower unit, yielding typical
faunas of the Cheiropteria glabra community and
graptolites of the N. kozlowskii Graptolite Zone. Here,
in the bed 12/13 the shift to higher δ13C values starts
with a value of + 2.9‰, rising to 3.7‰ in bed 13 at the
top of the N. kozlowskii Graptolite Zone. Above, in the
235
predominantly limy upper part of the limestone–marl
succession there is a drastic change to values between
6.7 and 8‰ (Fig. 4), starting in the beds yielding
brachiopods of the monospecific atrypid community.
Unfortunately, because the section is cut off by a fault,
the record of the isotope peak is not complete. However,
the highest values in the section (8‰) extend over a
“plateau” interval (values between 7 and 8‰) of about
7 m (Fig. 4) and may indicate that the peak did not rise to
higher δ13C values in this deep water section.
In the upper part of the predominately limestone
succession, which include the record of very high δ13C
values, there seems to be little variation in the
microfacies of the beds, except varying grain sizes.
The thickness of black, organic-rich limestone beds
ranges from centimetres to a few decimetres. Bioclastic
wackestone and packstone are the dominant facies
types. They are commonly laminated with relatively
thick laminae. The bioclasts are fine grained and rarely
exceed 1 mm in size. Larger bioclasts (e.g., crinoid
ossicles) commonly occur in distinct layers within the
limestone beds. Tabulate corals (heliolitids) occur rarely
and are clearly transported. Small spherical objects with
a wall of radial crystals and a diameter of less than
0.2 mm are common and could represent calcispheres,
although they can be confused with tranverse sections of
sponge spicules. The fine-grained matrix is commonly
developed as microspar. Lithoclasts and intraclasts are
not observed. Most of the bioclasts are not indicative for
typical shallow marine environments, except of scattered fragments of tabulate corals.
5. The Mušlovka and Požáry Quarry sections
Northeast of the Kosov area, several stratigraphically
equivalent shallow-water sections in the suburbs of
Prague have been sampled for stable isotopes (Fig. 2). In
addition to Mušlovka Quarry which was the first section
in the Prague Basin where the Lau Event was recorded
(Lehnert et al., 2003), a section of the upper Kopanina
Formation in the Požáry Quarry was sampled in detail.
5.1. Mušlovka Quarry
Carbon isotope data from the Mušlovka section (50°
01′ 56.2″ N, 14° 19′ 59.3″ E; Fig. 7) together with a brief
description of the succession is given by Lehnert et al.
(2003). For detailed descriptions of lithologies and
faunal content we refer to Bouček (1937) and Kříž
(1992).
In Mušlovka, the interval sampled for carbon
isotopes covers the strata of the upper 30 m within the
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Fig. 7. Sedimentary profile of the Mušlovka section (modified from Kříž and Schönlaub in Chlupáč et al., 1980) with δ13C record. Numbers on the
left side of the column correspond to the levels of Schönlaub's conodont samples. The graptolite subzonation is based on Štorch (1995), whereas the
conodont zonation is provided by Kříž and Schönlaub in Chlupáč et al. (1980). (a) Close-up of the critical peak interval showing the levels from beds
17 to 21 with the highest δ13C values. (b) Exposures of Kopanina and Požáry Formations in Mušlovka Quarry.
fritschi linearis Graptolite Zone to the top of the Ludlow
(Fig. 7). The δ13C values reach a maximum value of
+4.6‰ and “background values” below and above the
peak interval scatter around between − 0.4 and + 1.4‰
(with an average at about 0.5‰; Fig. 7; Lehnert et al.,
2003). The typical δ13C excursion starts with values of
+2.1 and + 2.0‰ in bed 16 (bed numbers refer to the
levels of conodont sampling by Kříž and Schönlaub in
Chlupáč et al., 1980) characterized by Dayia minor.
There is a slight decrease at the base of bed 17, just
above a thin black micritic layer (+ 1.4‰) which
contains almost no fossil remains (Bouček, 1937).
According to Manda (2003), there is a sequence
boundary on top of this layer and a stratigraphic gap.
Above, values constantly increase and the δ13C shift
reaches its maximum at the level of Schönlaub's sample
no. 18 (+ 4.6‰). It decreases to values around + 2.5‰ in
level 19, to +1.9‰ just at the level of conodont sample
20, and then goes back to normal data around + 1‰
within massive bed 21 (Fig. 7).
5.2. The Požáry Quarry section
5.2.1. Local framework
Near Řeporyje, the section at the entrance to the three
Požáry Quarries was sampled (50° 01′ 45.0″ N, 14° 19′
26.7″ E; Fig. 8). This is one of the most famous Silurian
sections in the Prague Basin, and was selected as an
Internation Basal Boundary Stratotype of the Přídolí
Series in 1984. The first bed-by-bed study was carried
out by Kříž (unpublished data) in the frame of
establishing a stratotype for the uppermost Silurian in
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
237
Fig. 8. Stratigraphical section showing the sampled part of the Ludfordian succession exposed close to the tunnel entrance at the Požáry Quarry and
the δ13C record within this interval; numbers on the left side of the column correspond to certain field units. Black dots in the isotope curve
correspond to the levels sampled. Palaeokarst horizons are marked by “PK”.
238
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
Fig. 9. Ludfordian strata (Kopanina Formation) at the entrance close to the tunnel in Požáry Quarry. Close-up of the uppermost part of the sampled
interval (beds 34 to 41) including the horizons with higher δ13C values and palaeokarst development. Scale bar = 0.5 m.
1984. The detailed results were subsequently published
by him and his colleagues (Kříž et al., 1986).
We started detailed sampling for stable isotopes in
the A. ploeckensis Conodont Zone at about 2 m below
bed 15 (FAD of P. siluricus at 0.77–0.63 m below the
top of bed 15; Kříž et al., 1986, p. 336) in the upper in a
brownish tuffitic shale interval with limestone lenses
(Fig. 8), the latter with faunas of the Cromus beaumonti
trilobite community, and continued sampling up to bed
41 of Kříž (1992), a level within the Ananaspis
fecunda–Cyrtia postera interval. Faunas coeval to the
N. kozlowskii Graptolite Zone occur in beds 33 and 34
(Kříž, 1998a,b, p. 193). The uppermost, thick-bedded
limestone interval sampled for carbon isotopes close to
the tunnel is shown in Fig. 9. Less densely spaced (0.5 to
1.0 m thick intervals) isotope sampling in the overlying
strata up to the Devonian was done some years ago by
Buggisch (unpublished data), providing background
information that these data just include values reflecting
the “normal background record” for the Ludlow. These
unpublished data are not shown in Fig. 8, because there
is no precise reference to the horizons numbered by Kříž
(1992), but they indicated to us that our sampling
covered the Lau Event interval.
5.2.2. Isotope record and microfacies
The sedimentary facies of the lowermost shaly
interval at Požáry is lithologically similar to the deeper
water limestones in the lower part of the Kosov section,
as both consists of brownish deeper water, tuffitic shales
with limestone lenses (Fig. 8). However, there is a rapid
shallowing observed within the interval sampled in
detail for stable isotopes. Above the lowermost shaly
interval, this facies alternates with bioclastic wacke- and
packstones (beds 15 to 18). In bed 18 and upwards,
normally graded grainstone beds with an irregular
erosive base (tempestites, overlain by dark wacke- to
packstone; Fig. 10D) cutting into underlying dark
bioclastic wackestones. Wacke- and grainstones, but
mainly packstones are present, displaying predominantly crinoidal remains, but also a high content of trilobites,
brachiopods, and nautiloids (Fig. 10 A–C, E).
In the lower part of the succession up to bed 27
(+ 3.2‰), δ13C values are usually between − 0.3‰ and
+1.1‰, with the exception of a few very low values in
beds 18, 23, and 24 (Fig. 11). Using Alizarin S to
distinguish between limestone and dolomite, a lot of
dispersed dolomite as well as dolomicrosparitic nodules
(Fig. 10D, E) and layers have been observed in several
beds (yellowish weathering colour) in this interval and
higher up in the massive beds 33 and 34 (e.g. bed 34;
Fig. 10D), where also the first evidences for palaeokarst
were detected (bed 33; Fig. 10A). From beds 34 to bed
39, δ13C values scatter mainly between + 2 and + 3‰
between, but this peak interval includes several samples
with higher δ13C values around +3‰ (+ 3.1, + 3.5,
+3.2, and +3.5‰) indicating an diagenetic overprint
caused by dissolution and dolomitisation processes.
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
In this upper part of the sampled succession, many
grainstone layers (partly tempestites) as well as palaeokarst features (sediment-filled dissolution cavities in beds
33, 37, 41) have been observed. A large sediment-filled
dissolution cavity is observed in bed 37 (Fig. 11; sample
BO 647; filled with finely laminated mudstone and very
thin wacke- to packstone layers). The walls of these
cavities are covered by coarse sparitic cements and the
vugs are filled by lime mud (Fig. 10A; dark mudstone) or
marine bioclastic wacke- to packstone layers (Fig. 11).
6. Discussion of the δ13C values from the Prague
Basin
6.1. Interpretation of the δ13C dataset
At the Kosov Quarry the positive δ13C shift starts in
the uppermost part of the N. kozlowskii Biozone (Fig. 4).
The values in the subsequent part of the section (between
6.7 and 8‰) show no indication of a decrease in δ13C.
This “plateau” indicates a high sedimentation rate in this
area of the Kosov Quarry. In the Mušlovka Quarry
section, the peak interval is recorded, but with a
maximum δ13C value of 4.6‰ probably displaying a
hiatus at the sequence boundary shown in Fig. 7. The
shift starts below in the approximately 0.7 m thick bed
characterised by with abundant Dayia minor, which is
overlain by an almost unfossiliferous, 0.15 m thick
distinct dark clayey limestone (approx. 0.15 m). Manda
(2003) documents that this dark grey interval corresponds to a sequence boundary related to erosion and/or
hiatus in the eastern part of the central segment of the
Prague Basin. The δ13C values − 0.3‰ and + 1.1 in the
lower part of the succession exposed in the Požáry
Quarry section (Fig. 8) represent the regular isotopic
background except one higher value within bed 27
(3.2‰) and a few very low values in beds 18, 23, and 24.
The peak interval including beds 34 to 39 was affected
by dolomitisation and karstification leading to a strong
diagenetic overprint as displayed by the low values
mainly between 2 and 3‰ and only a few samples with
values of 3.1, 3.5, 3.2, and 3.5‰.
6.2. Implications for regional geology
Regional studies on sedimentology and facies
distribution indicate a widespread regression in wide
parts of the basin during the middle Ludfordian (Horný,
1955a). Later, Kříž (1991) presented a new model for
the Silurian of the Prague Basin based on the
investigation of hundreds of boreholes. In this model,
he shows that facies distribution and development was
239
controlled by synsedimentary tectonics and volcanism.
This leads to a very complex picture of the basin history
and complicates correlation of tectonically controlled
sea-level changes. Therefore, separation of regional
signals from global eustatic sea-level fluctuations is
difficult (Kříž, 1991). However, based on sedimentary
data a first regression is observed just below the oldest
beds bearing taxa of the Ananaspis fecunda–Cyrtia
postera trilobite–brachiopod community (Havlíček and
Štorch, 1990) in the upper P. siluricus Conodont Zone.
In the Kosov Quarry, the positive δ13C excursion during
the Ludfordian Lau Event interval starts with an increase to
higher values in the upper Neocullograptus kozlowskii
Graptolite Zone (upper Polygnathoides siluricus Conodont
Zone). This fits stratigraphically with the start of the
isotopic shift in Mušlovka. Here, the event was described
for the first time from the Prague Basin by Lehnert et al.
(2003) but the observed maximum in the δ13C values is
+4.6‰, indicating that the sequence boundary on top of
bed 17 in this section was related to erosion or nondeposition. This quarry is close to the Požáry section where
almost the entire peak interval is absent.
In the Kosov Quarry section, the beds bearing the
Atrypoidea lingulata community are in the upper part
of mainly shaly and marly succession with a lot of
tuffitic material, and abundant Dayia minor and Septatrypa thisbe occur in the uppermost part of the Atrypoidea lingulata horizons. Due to the different
tectonical development at the Nová Ves volcanic centre,
coeval strata in Mušlovka and Požáry are presumably
represented by a succession of Cephalopod limestones
with stratigraphic gaps caused by erosion, subaerial
(palaeokarst) or submarine solution (hardgrounds). The
partly turbititic deposition near the flanks of the volcanic
centre reflects a rather quick accumulation of mixed
carbonate–siliciclastic material. However, in Mušlovka
the peak starts within the distinct and massive Dayia
minor coquina horizon. In contrast, another massively
bedded and a few decimetres thick interval with Dayia
minor occurs also far more than 10 m below the start of
the isotope shift and, therefore, represents, based clearly
on the isotope data, not a coeval occurrence of this
monospecific assemblage. Such exceptional occurrences may be diachronous due to the adaptation of a
taxon to certain restricted environmental conditions.
Hiatuses in shallow-water environments expressed by
definite sequence boundaries and palaeokarst features
were triggered by sea-level fluctuations affecting large
parts of the basin (Horný, 1955a; Havlíček and Štorch,
1990; Manda, 2003). At Požáry, the sampled succession
reveals a rapid shallowing during the Lau Event with
shingling facies due to sea-level fluctuations and
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O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
241
Fig. 11. Micrograph of a sediment-filled dissolution cavity formed within crinoidal bioclastic packstone (sample BO 647, lower 10 cm of bed 37,
Požáry section; cp. Fig. 9). Scale bar = 1 cm.
palaeokarst development connected with several phases
of emmersion. The δ 13C record of the section is
presumably incomplete like in Mušlovka, but also
shows a diagenetic overprint.
Based on record of the high positive shift (up to 8‰)
observed in the Kosov Quarry, it may be argued, that – if
the shallow-water successions of the Prague Basin would
completely cover the event interval – even much higher
values than 8‰ would be expected there, similar to the
coeval situation in Baltica were the highest positive δ13C
values are present in shallow-water environments
(Wigforss-Lange, 1999). Examples of this depth dependence of δ13C values from other Phanerozoic time slices
have been compiled by Munnecke et al. (2003). The
comparison of the δ13 C record in the three most
important sections reflects that based on the pronounced
positive δ13C in the studied section in Kosov Quarry, the
shallow-water succession in the Mušlovka Quarry
section is substantially reduced and presumably incomplete, and the reduced succession exposed at the entrance
of the Požáry Quarries is the presumably most
incomplete and diagenetically altered section.
The main trigger of the extinction events in the Prague
Basin, which are observed prior to the positive shift in
δ13C (at the base of N. inexpectatus, N. kozlowskii, and
Monograptus latilobus graptolite zones; Manda, 2003),
remain unclear. They might be connected with some
strong volcanic ash falls coeval to global and/or regional
sea level fluctuations and changes in bioproductivity and
palaeoclimate during the Lau Event interval.
6.3. Comparison with the δ13C record in low-latitudes
The δ13C record from other parts of the world
includes only datasets from tropical to subtropical
regions. The present study from the Prague Basin
shows that the isotopic signal from deeper environments
of this area, varying between 6 and 8‰, is in accordance
to that in deeper platform facies of subequatorial Baltica
with a maximum of 7.6‰ (Wigforss-Lange, 1999). Due
to the inferred stratigraphic gaps there are no shallowwater isotopic data available from the Prague Basin that
can be confidently and directly compared with the
extremely strong shift to a maximum of 11.2‰ in
subtropical shallow water sediments of southern Sweden
(Wigforss-Lange, 1999) and 12‰ in Australia (Andrew
et al., 1994). The δ13C record from other low latitude
regions shows lower positive shifts and not the same
intensity as in Bohemia. The maximum values for the
positive carbon isotope excursion in the eastern Baltic
are at 5‰ (Kaljo et al., 1997), and in North America at
about 4‰ (Saltzman, 2001). From higher latitudes only
Fig. 10. Micrographs from the upper Kopanina Formation exposed between the entrance to the Požáry Quarry and the northern tunnel entrance. (A)
Tempestitic bioclastic grainstone layer showing gradation, originally open cavities (brachiopod and nautiloid shells) filled by coarse sparite;
grainstone covered by a dark bioclastic wacke- to packstone, sample BO 612, bed 18. (B) Bioclastic pack- to grainstone with brachiopods and
nautiloids. Sample BO 631, upper part of bed 33. (C) Bioclastic grainstone, with abundant crinoid remains, some trilobites and brachiopods, and a
reworked solitary coral with micritic infill, sample BO 656, bed 41. (D) Nodular bioclastic limestone, bioclastic grainstone and dolomicrosparite
nodules floating in a crinoidal packstone matrix, sample BO 641, top of bed 34. (E) Bioclastic grainstone with brachiopods, trilobites, nautiloids,
crinoids, and reworked dolomicrosparitic clasts and steinkern fillings, sample BO 628, bed 33. Scale bar = 0.5 cm.
242
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
δ13Corg values (showing a positive shift of about 5 to
6‰) are available from the Carnic Alps in a latitudinally
slightly higher area of peri-Gondwana (Wenzel, 1997).
On Gotland, the late Ludfordian δ13C excursion shows
values of up to 8.8‰ (Samtleben et al., 2000). In the upper
Hemse Group (När Formation according to Calner et al.,
2004) the values start to increase from base values of
+0.15‰ within the uppermost P. siluricus Conodont
Zone. Peak values of nearly 9‰ are reported from the
upper Eke Formation, corresponding to the Upper
Icriodontid Conodont Subzone. On western Gotland the
isotope values increase continuously indicating a sedimentological record without significant gaps (Samtleben
et al., 2000). On eastern Gotland, in contrast, the boundary
between Hemse Group and Eke Formation is marked by a
pronounced discontinuity surface overlain by detritic
limestones, small reef mounds and stromatolites (Calner,
2005a). These are interrupted by several small palaeokarst
cavities indicating deposition in extremely shallow water
with repeated phases of emmersion (Cherns, 1982, 1983;
Samtleben et al., 1996). In the uppermost Hemse Group on
eastern Gotland, immediately below the boundary, isotope
values of 1.5‰ have been measured from brachiopod
shells (locality Botvide 1), and values of 4.6‰ are
measured in the lowermost Eke Beds in the nearby locality
Nyan 2 (Samtleben et al., 2000). A recent study by Calner
and Eriksson (2006) from the Burgen outlier on eastern
Gotland shows the rapid shallowing during the event
interval reflected by a shift from deeper water marls
overlain by a conglomerate to microbial boundstones.
It is interesting to note that infillings of karstic cavities
with marine sediments are observed in at least three beds
in the Požáry section within the isotope excursion (beds
33, 37, and 41). Similar to eastern Gotland, this outcrop
is characterised by a rapid shift from deeper-water shaly
to shallow-water depositional environments. Obviously,
the times of increasing isotope values are characterised
by short-term sea-level fluctuations. However, since no
evidence for glacial deposits has been reported from this
time slice, the reason for these fluctuations remain
unclear. Nevertheless, stratigraphic gaps in shallowwater deposits are a characteristic feature of the Silurian
carbon isotope excursions (Munnecke et al., 2003).
7. Conclusions
(1) A pronounced positive shift in δ13C in a deeper water
section at the Kosov Quarry is recorded, starting in the
upper Neocullograptus kozlowskii Graptolite Zone.
(2) The sudden isotopic change observed in the Kosov
Quarry is comparable to the datasets from other
palaeogeographic areas and fits especially well with
(3)
(4)
(5)
(6)
data from the deeper shelf of Sweden. The data from
Bohemian, together with those from Sweden and
Australia show the highest δ13C values up to date
across the Lau Event.
Data across the event interval in shallow water
sections of the Prague Basin demonstrate a widespread regression indicated by a reduced sedimentation rate of Cephalopod limestone biofacies and in
certain areas by stratigraphic gaps caused by
subaerial erosion due to a significant sea-level fall.
Stable isotope studies across the event interval in
sections with low diagenetic overprint provide a tool
for correlation and detecting hiatuses. Faunal
zonations are the base for a biostratigraphic frame,
but macrofaunal communities and biozones which
are only partly preserved or even diachronous may
not show any evidence for a gap and may partly be
problematic to correlate with confidence.
Faunal extinctions preceed the shift in δ13C during
the Lau Event like in coeval deposits on Gotland.
In contrast to classical areas like Gotland, were
mainly open shelf faunas are affected by the
extinction events and benthic shelf communities
are re-established afterwards, there is a complete
overturn in macrofaunal assemblages during the Lau
event in the Prague Basin and completely new faunas
are invading the biologically “devastated” basin.
Acknowledgements
We gratefully acknowledge the careful, critical and
very constructive reviews by Mikael Calner (University
of Lund, Sweden) and Dimitri Kaljo (University of
Tallinn, Estonia) and all the valuable suggestions by T.
Servais (CNRS, Lille, France) which strongly improved
the earlier version of this publication. Thanks also to
Tina Gocke (University of Erlangen, Germany) for
providing thin sections from the Požáry Quarry section
for study and to Radek Morávek (Charles University,
Prague, Czech Republic) for providing a Coreldraw file
of the location map shown on figure 2. This project was
carried out during OL's stay at the Charles University in
Prague (Czech Republic) in the frame of the “Nachkontakt-Programm” of the Alexander von Humboldt
Foundation (Bonn, Germany), and the support by the
Humboldt Foundation is greatly acknowledged. This
paper is a contribution to IGCP 503.
References
Andrew, A.S., Hamilton, P.J., Mawson, R., Talent, J.A., Whitford, D.J.,
1994. Isotopic correlation tools in the mid-Palaeozoic and their
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
relation to extinction events. Australian Petroleum Exploration
Association (APEA) Journal 34, 268–277.
Azmy, K., Veizer, J., Bassett, M.G., Copper, P., 1998. Oxygen and
carbon isotopic composition of Silurian brachiopods: implications
for coeval seawater and glaciations. Geological Society of America
Bulletin 100, 1499–1512.
Bickert, T., Pätzold, J., Samtleben, C., Munnecke, A., 1997.
Paleoenvironmental changes in the Silurian indicated by stable
isotopes in brachiopod shells from Gotland, Sweden. Geochimica
et Cosmochimica Acta 61, 2717–2730.
Bouček, B., 1937. Stratigrafie siluru v dalejském údolí u Prahy a v jeho
nejbližším okolí. Rozpravy II. Třídy České Akademie 46, 1–20.
Calner, M., 2005a. A Late Silurian extinction event and anachronistic
period. Geology 33, 305–308.
Calner, M., 2005b. Silurian carbonate platforms and extinction
events — ecosystem changes exemplified from Gotland, Sweden.
Facies 51, 584–591.
Calner, M., Eriksson, M., 2006. Evidence for rapid environmental
changes in low latitudes during the Silurian Lau Event: the Burgen1 drillcore, Gotland, Sweden. Geological Magazine 143, 15–24.
Calner, M., Jeppsson, L., Munnecke, A., 2004. The Silurian of Gotland —
Part I: Review of the stratigraphic framework, event stratigraphy, and
stable carbon and oxygen isotope development. Erlanger Geologische
Abhandlungen. Sonderband 5, 113–131.
Čáp, P., Vacek, F., Vorel, T., 2003. Microfacies analysis of Silurian and
Devonian type sections (Barrandian, Czech Republic). Czech
Geological Survey Special Papers 15 (40 pp.).
Caputo, M.V., 1998. Ordovician–Silurian glaciations and global sealevel changes. In: Landing, L., Johnson, M.E. (Eds.), Silurian
Cycles — Linkages of Dynamic Stratigraphy with Atmospheric,
Oceanic, and Tectonic Changes. New York State Museum Bulletin,
vol. 491, pp. 15–25.
Cherns, L., 1982. Palaeokarst, tidal erosion surfaces and stromatolites
in the Silurian Eke Formation of Gotland, Sweden. Sedimentology
29, 819–833.
Cherns, L., 1983. The Hemse–Eke boundary: facies relationships in
the Ludlow Series of Gotland, Sweden. Sveriges Geologiska
Undersokning. Serie C, Avhandlingar och Uppsatser 800, 1–45.
Chlupáč, I., 1987. Ecostratigraphy of Silurian trilobite assemblages of
the Barrandian area, Czechoslovakia. Newsletter on Stratigraphy
17, 169–186.
Chlupáč, I., Kříž, J., Schönlaub, H.P., 1980. Field Trip E. Silurian and
Devonian conodonts of the Barrandian. In: Schönlaub, H.P. (Ed.),
Second European Conodont Symposium—ECOS II. Guidebook —
Abstracts. Abhandlungen Geologische Bundesanstalt, vol. 35,
pp. 147–180.
Cramer, B.D., Saltzman, M.R., 2005. Sequestration of 12C in the deep
ocean during the early Wenlock (Silurian) positive carbon isotope
excursion. Palaeogeography, Palaeoclimatology, Palaeoecology
219, 333–349.
Díaz-Martínez, E., Acosta, H., Cardenas, J., Carlotto, V., Rodríguez, R.,
2001. Paleozoic diamictites in the Peruvian Altiplano: evidence and
tectonic implications. Journal of South American Earth Sciences 14,
587–592.
Ferretti, A., Kříž, J., 1995. Cephalopod limestone biofacies in the
Silurian of the Prague Basin, Bohemia. Palaios 10, 240–253.
Fiala, F., 1982. Basaltoid diabase from Hostim with indications of
hematite mineralization. Časopis pro Mineralogii a Geologii 27,
173–185.
Fortey, R.A., Wilmot, N.V., 1991. Trilobite cuticle thickness in relation
to palaeoenvironment. Paläontologische Zeitschrift 65, 141–151.
243
Grahn, Y., Caputo, M.V., 1992. Early Silurian glaciations in Brazil.
Palaeogeography, Palaeoclimatology, Palaeoecology 99, 9–15.
Havlíček, V., Štorch, P., 1990. Silurian brachiopods and benthic
communities in the Prague Basin. Rozpravy Ústředního Ústavu
Geologického 48, 1–275.
Havlíček, V., Horný, R., Chlupáč, I., Šnajdr, M., 1958. Průvodce ku
geologickým exkurzím do Barrandienu. Sbírka Geologických
Průvodců 1, Český Geologický Ústav (157 pp.).
Horný, R., 1955a. Studie o vrstvách budňanských v západní části
barrandienského siluru. Sborník Ústředního Ústavu Geologického
21, 315–448.
Horný, R., 1955b. Báse vrstev kopaninských eβ1 na jihozápadním
okraji vulkanické facie (Kosov u Berouna). Věstník Ústředního
Ústavu Geologického 30, 81–86.
Horný, R., 1960. Stratigraphy and tectonics of the western closures of
the Silurian–Devonian synclinorium in the Barrandian area.
Sborník Ústředního Ústavu Geologického 26, 495–524.
Jeppsson, L., 1984. Sudden appearances of Silurian conodont lineages;
provincialism or special biofacies? In: Clark, D.L. (Ed.), Conodont
Biofacies and Provincialism. Geol. Society of America Special
Paper, vol. 196, pp. 103–112.
Jeppsson, L., 1987. Lithological and conodont distributional evidence
for episodes of anomalous oceanic conditions during the Silurian.
In: Aldridge, R.J. (Ed.), Palaeobiology of Conodonts. Ellis
Horwood Ltd., Chichester, pp. 129–145.
Jeppsson, L., 1990. An oceanic model for lithological and faunal
changes. Journal of the Geological Society (London) 147, 663–674.
Jeppsson, L., 1993. Silurian events: the theory and the conodonts.
Proceedings of the Estonian Academy of Sciences. Geology, vol. 42,
pp. 23–27.
Jeppsson, L., 1997. Recognition of a probable secundo-primo event in
the Early Silurian. Lethaia 29, 311–315.
Jeppsson, L., 1998. Silurian oceanic events: summary of general
characteristics. In: Landing, E., Johnson, M.E. (Eds.), Silurian
Cycles: Linkages of Dynamic Stratigraphy with Atmospheric,
Oceanic, and Tectonic Changes (James Hall Centennial Volume).
New York State Museum Bulletin, vol. 491, pp. 239–257.
Jeppsson, L., Aldridge, R.J., 2000. Ludlow (late Silurian) oceanic episodes
and events. Journal of the Geological Society (London) 157, 1137–1148.
Jux, U., Steuber, T., 1992. Ccarb- und Corg-Isotopenverhältnisse in der
silurischen Schichtenfolge Gotlands als Hinweise auf Meeresspiegelschwankungen und Krustenbewegungen. Neues Jahrbuch fur
Geologie und Palaontologie. Monatshefte 7, 385–413.
Kaljo, D., Boucot, A.J., Corfield, R.M., Le Herisse, A., Koren, T.N.,
Kříž, J., Männik, P., Märss, T., Nestor, V., Shaver, R.H., SiveterViira,
D.J., Viira, V., 1995. Silurian Bio-Events. In: Walliser, O.H. (Ed.),
Global Events and Event Stratigraphy in the Phanerozoic. Springer,
Berlin, pp. 173–223.
Kaljo, D., Kiipli, T., Martma, T., 1997. Carbon isotope event markers
through the Wenlock–Přídolí sequence at Ohesaare (Estonia) and
Priekule (Latvia). Palaeogeography, Palaeoclimatology, Palaeoecology 132, 211–223.
Kaljo, D., Kiipli, T., Martma, T., 1998. Correlation of carbon isotope
events and environmental cyclicity in the East Baltic Silurian. In:
Landing, L., Johnson, M.E. (Eds.), Silurian Cycles — Linkages
of Dynamic Stratigraphy with Atmospheric, Oceanic, and
Tectonic Changes. New York State Museum Bulletin, vol. 491,
pp. 297–312.
Kříž, J., 1991. The Silurian of the Prague Basin (Bohemia): tectonic,
eustatic, and volcanic controls on facies and faunal development.
Special Papers in Palaeontology 44, 179–204.
244
O. Lehnert et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 245 (2007) 227–244
Kříž, J., 1992. Silurian Field Excursions: Prague Basin (Barrandian),
Bohemia. Geological Series - National Museum Of Wales, Cardiff
13 (111 pp.).
Kříž, J., 1998a. Silurian. In: Chlupáč, I., Havlíček, V., Kříž, J., Kukal,
Z., Štorch, P. (Eds.), Palaeozoic of the Barrandian. Czech
Geological Survey, Prague, pp. 70–101.
Kříž, J., 1998b. Recurrent Silurian–Lowest Devonian cephalopod
limestones of Gondwanan Europe and Perunica. In: Landing, E.,
Johnson, M.E. (Eds.), Silurian Cycles: Linkages of Dynamic
Stratigraphy with Atmosphaeric, Oceanic, and Tectonic Changes
(James Hall Centennial Volume). New York State Museum
Bulletin, vol. 491, pp. 183–198.
Kříž, J., 1999. Bivalvia dominated communities of Bohemian type
from the Silurian and Lower Devonian carbonate facies. In:
Boucot, A.J., Lawson, J.D. (Eds.), Palaeocommunities: A case
study from the Silurian and Lower Devonian. World and Regional
Geology series, vol. 11. Cambridge University Press, pp. 229–252.
Kříž, J., Jaeger, H., Paris, F., Schönlaub, H.P., 1986. Přídolí — the
fourth subdivision of the Silurian. Jahrbuch der Geologischen
Bundesanstalt Wien 129, 291–360.
Kříž, J., Degardin, J.M., Ferretti, A., Hansch, W., Gutiérrez Marco, J.C.,
Paris, F., Piçarra, D-., Almeida, J.M., Robardet, M., Schönlaub, H.P.,
Serpagli, E., 2003. Silurian stratigraphy and palaeogeography of
Gondwanan and Perunican Europe. In: Landing, E., Johnson, M.E.
(Eds.), Silurian Lands and Seas: Paleogeography outside of Laurentia.
New York State Museum Bulletin, vol. 493, pp. 105–178.
Krs, M., Krsová, M., Pruner, P., Havlíček, V., 1986. Paleomagnetism,
palaeogeography and multi-component analysis of magnetisation
of Ordovician rocks of the Barrandian in the Bohemian Massif.
Sborník Geolologických Věd, Užitá Geofyzika 22, 9–48.
Lehnert, O., Frýda, J., Buggisch, W., Manda, S., 2003. A first report of
the Ludlovian Lau event from the Prague Basin (Barrandian,
Czech Republic). In: Ortega, G., Aceñolaza, G.F. (Eds.),
Proceedings of the 7th International Graptolite Conference and
Field Meeting of the International Subcommission on Silurian
Stratigraphy. Serie Correlación Geológica, vol. 18. Instituto
Superior de Correlación Geológica (INSUGEO), pp. 139–144.
Manda, S., 2003. Vývoj a společenstva silurských a rannĕ devonských
hlavonožcových vápenců (pražská pánev, Čechy). Unpublished
Diploma thesis; MS Přírodovědecká fakulta, Universita Karlova,
Praha, 114 pp. and supplement I–XIV.
Martma, T., Brazauskas, A., Kaljo, D., Kaminskas, D., Musteikis, P.,
2005. The Wenlock–Ludlow carbon isotope trend in the Vidukle
core, Lithuania, and its relations with oceanic events. Geological
Quarterly 49, 223–234.
Modzalevskaya, T.L., Wenzel, B., 1999. Biostratigraphy and geochemistry of Upper Silurian brachiopods from the Timan–Pechora
region (Russia). Acta Geologica Polonica 49, 145–157.
Munnecke, A., Samtleben, C., Bickert, T., 2003. The Ireviken Event in
the lower Silurian of Gotland, Sweden — relation to similar
Palaeozoic and Proterozoic events. Palaeogeography, Palaeoclimatology, Palaeoecology 195, 99–124.
Saltzman, M.R., 2001. Silurian δ13C stratigraphy: a view from North
America. Geology 29 (8), 671–674.
Samtleben, C., Munnecke, A., Bickert, T., Pätzold, J., 1996. The Silurian
of Gotland (Sweden): facies interpretation based on stable isotopes in
brachiopod shells. Geologische Rundschau 85, 278–292.
Samtleben, C., Munnecke, A., Bickert, T., 2000. Development of
facies and C/O-isotopes in transects through the Ludlow of
Gotland: evidence for global and local influences on a shallowmarine environment. Facies 43, 1–38.
Scotese, C.R., McKerrow, W.S., 1990. Revised world maps and
introduction. In: McKerrow, W.S., Scotese, C.R. (Eds.), Palaeozoic
Palaeogeography and Biogeography. Geological Society of
London Memoir, vol. 12, pp. 1–21.
Štorch, P., 1994. Graptolite biostratigraphy of the Lower Silurian (Llandovery and Wenlock) of Bohemia. Geological Journal 29, 137–165.
Štorch, P., 1995. Upper Silurian (upper Ludlow) graptolites of the
N. inexpectatus and N. kozlowskii biozones from Kosov Quarry
near Beroun (Barrandian area, Bohemia). Bulletin of the Czech
Geological Survey 70, 65–89.
Štorch, P., 1998. VIII. Volcanism. In: Chlupáč, I., Havlíček, V., Kříž,
J., Kukal, Z., Štorch, P. (Eds.), Palaeozoic of the Barrandian
(Cambrian to Devonian). Czech Geological Survey, pp. 149–164.
Stricanne, L., Munnecke, A. , Pross, J. , 2006. Assessing mechanisms
of environmental change: Palynological signals across the late
Ludlow (Silurian) positive isotope excursion (δ13C, δ18O) on
Gotland, Sweden. Palaeogeography, Palaeoclimatology, Palaeoecology 230, 1–31.
Tait, J., Bachtadse, V., Soffel, H., 1995. Upper Ordovician palaeogeography of the Bohemian Massif: implications for Armorica.
Geophysical Journal International 122, 211–218.
Turek, V., 1983. Hydrodynamic conditions and the benthic community
of upper Wenlockian calcareous shales in the western part of the
Barrandian (Kosov Quarry). Časopís pro Mineralogii a Geologii
28, 245–260.
Turek, V., 1990. Comments to Upper Wenlock zonal subdivisions in
the Silurian of Central Bohemia. Časopís pro Mineralogii a
Geologii 35, 337–353.
Wenzel, B.C., 1997. Isotopenstratigraphische Untersuchungen an
silurischen Abfolgen und deren paläozeanographische Interpretation. Erlanger Geologische Abhandlungen 129, 1–117.
Wenzel, B., Joachimski, M.M., 1996. Carbon and oxygen isotopic
compositions of Silurian brachiopods (Gotland/Sweden): palaeoceanographic implications. Palaeogeography, Palaeoclimatology,
Palaeoecology 122, 143–166.
Wigforss-Lange, J., 1999. Carbon isotope 13C enrichment in upper
Silurian (Whitecliffian) marine calcareous rocks in Scania,
Sweden. GFF 121, 273–279.