Diss. Nr. 3885
Geologie
Petrographie
und
und seiner
des Damavand
Umgebung (Zentral-Elburz), Iran
Abhandlung
derWGrde eines
Erlangung
zur
Doktors der Naturwissenschaften
der
Eidgenossischen
Technischen Hochschule Zurich
vorgelegt
von
PETER ALLENBACH
dipl. Ing.-Geologe
geboren
von
am
ETH
23.Marz1936
Adelboden, Kanton Bern
Angenommen
auf
Antrag
von
Prof. Dr. A. Gansser, Referent
Prof. Dr. C. Burri,
1966
•
Korreferent
Uster, Offsetdruck P.Zimmermann
SUMMARY
The
of 1: 50'000. The
results at
scale
a
region studied by
high Quaternary
nature
the
on
The
km2
of almost 2000
area
eastern Central Elburz.
The
that is dealt with in this
principal object
was
study lies
to map the
in the
area on a
scale
geological map of Plate 1 is a simplified presentation of the
of 1: lOO'OOO; it extends also over the eastern neighbouring
R. STEIGER
The
.
core
of the
area
volcano of Damavand. This imposes
study, and
a
sedimentary
areas
by the
5670
m
strongly petrographic
of earlier volcanic
description
of the
stratigraphy
is formed
a
phases
is dealt with
is also included.
only summarily.
The sediments range from young Precambrian to the Eocene, but several stra-
tigraphical
gaps,
some
shelf-type depositional
eugeosynclinal
of
long duration,
sediments
are
break the succession.
completely missing. Compared
of the Elburz the Paleozoic formations show
The first
Zaigun
sedimentary cycle
Miogeosynclinal,
reigned throughout the whole interval, and
environments
is formed
strikingly
a
the
by
thin
with other
areas
development.
Bayandor, Soltanieh, Barut,
and Lalun Formations. It includes upper Precambrian and Lower Cam¬
brian in
a
predominantly
stones, sedimentation
detrital facies. After the deposition of the Lalun sand¬
in the
area
south of the Main Thrust
was
broken
by
that lasted until the Upper Devonian Geirud Formation. North of the Main
the first
sedimentary cycle
a
gap
Thrust,
continued with the Mila Formation into the Upper
Cambrian. However, the lack of the
trilobite-bearing
Members 2 and 3 from
the Mila Formation indicates local emergence and erosioninthe
Upper Cambrian.
second, less complete sedimentary cycle begins with the transgression
of the sandy Geirud Formation (Upper Devonian), which lies concordantly on
A
the
underlying
rocks.
Lower Carboniferous is
Upper Carboniferous and
Formation.
Lower Permian Dorud Formation
Middle Permian Ruteh
zoic. Marine
Upper
the bean-ore that
the
equivalent
Formation,
are
a
represented by the Mobarak
Lower Permian
found
only
are
missing; rocks of the
in the southernmost
calcareous succession,
Permian does not
occur
in the southern
locally lies above the Ruteh
The
area.
closes the Paleo¬
Elburz, although
Formation may be
regarded
as
of the Nesen Formation.
The Trias is
part
can
represented by the calcareous Elikah Formation, but the upper
primarily absent. An epeirogenic uplift at the end of the Trias, with
be
Thrust, brought about a relief
the
Shemshak
Formation.
by
transgressed
monotonous, sandy-shaley Shemshak Formation (Rhaetic to Lower
related extrusions of diabase south of the Main
that
was
The
introduces the third
Bajocian)
southern
sedimentary cycle.
area) locally contains coal.
Its lower part
Marine conditions
occur
(in the
in the upper
deposition
leading
jocian-Callovian), which
changed during the Bajocian,
calcareous-marly Dalichai Formation (Upper Ba¬
probably has a heterochronous lower boundary. Se¬
veral localities delivered
good
part of the
sequence.
to the
Sedimentation conditions
of the
R.STEIGER (in the press):
ammonite faunas of the Bathonian and Callovian.
Geologie der
West-Firuzkuh-Area (Zentral El¬
burz/Iran).
7
succeeding, purely calcareous Lar Formation embraces theOxfordian,
Kimmeridgian and possibly Lower Tithonian. At the end of the Lar times a re¬
gression occured over the area, bringing about the deposition of gypsum in the
The
north. After the complete emergence, diabases
mation of the Lower
Cretaceous). During the Aptian
mation
from the north,
are
missing south of the
Nim Rud
third
sedimentary cycle
During the
Upper Cretaceous
came
so
on
the
the
(Campanian-(?) Maestrichtian)
to its close.
Tertiary the
Lower
par¬
Thrust,
directly
that there the formations of the younger Cretaceous transgress
Lar Limestones. With the
again
area was
For¬
and the Orbitolina limestones of the Tiz Kuh For¬
These
deposited.
were
the
that
over an area
(Gypsum-"Melaphyre"
with the extent of the gypsum
tially flooded
extruded
were
closely corresponds
area
suffered orogenic movements, which
caused the layout of most of the structures. The
mented
in
succeeding erosion is docu¬
widely distributed conglomerates of the Ziarat Formation which
the
by
parts lie with
strong discordance above theMesozoic-Paleozoic
a
The upper part of the Ziarat Formation is formed
by
basement.
Alveolina and Nummulite
(? Illerdian, Cuisian to Middle Lutetian). The pyroclastic rocks of
Karaj Formation, missing from the area of the "Paleozoic Central Range",
limestones
the
likewise belong to the Eocene. Formations of younger Tertiary age could not be
established in the studied
area.
Quaternary, post-orogenic deposits
in the Lar
at Pulur and the Haraz
valley,
from the terraces of the lower Lar
indicating
The origin of
a
A
C^-dating
valley gave a minimum
(early WUrm)
directly related
volcano, which dammed
In the studied
fairly widespread
valley.
young Pleistocene age
probable
these is
are
as
plant material
age of 38'500 years,
for the Lar terraces
to the southern lavas of the Damavand
and caused the
at least five
area
in the area,
of
infilling
of the Lar lake.
-volcanic
magmatic
phases
may be dis¬
tinguished.
A lower
Paleozoic, imprecisely
of the dykes that
anticlinorium.
occur
These
dated
phase corresponds
to the intrusion
in the oldest formations of the Aineverzan
are
mostly
of
altered diabases and
-
Dalichai
more rare
lampro-
phyres.
The
of the Ainevarzan -Dalichai structure
area
was
also the site of
a
vol¬
Triassic/Rhaetic-Liassic boundary, where thick flows of
amygdaloidal diabase ("melaphyre") separate the Elikah from the overlying
canic
phase
on
the
Shemshak Formation. The thickness of the basic volcanics decreases from the
south to the north. North of the Main Thrust in the studied
pre-Shemshak volcanism could be found.
to
area no
was
trace of the
probably
related
post-Triassic epeirogeny.
In the northern
part of the
the Tiz Kuh Formation. These
bases, though
some are
area
basic lavas
it is
Pardomand,
possible
time, played
a
exposed
at the bottom of
amygdaloidal, mostly strongly altered dia¬
relatively fresh with a typical ophitic structure. The
and
The Lower Cretaceous volcanism is
ments;
are
are
lavas reach thicknesses of at least 200
between Vahne and
8
The volcanism
role.
One
zone
be followed
probably
that the thrust of
determining
m.
can
of
great thickness lies
along
its strike to the east.
also related to epeirogenic
Baidjan,
which
was
already
move¬
active at that
In the area north of
Shemshak Formation but
Baidjan the dykes increase in abundance; they cut the
only rarely enter into the Dalichai and lower part of
the Lar Formation. Most
are
less
that is
area
The
common.
suggests
an
The
the
roughly
lamprophyres (of
are
cannot be dated
dykes
same as
the kersantite
accurately.
over an
that of the Lower Cretaceous volcanism
association with the latter.
beginning
of the
Tertiary volcanic activity
is marked
sive olivine basalts and andesites in the Ziarat Formation
during
group); diabases
Their extent
the Middle Eocene vast quantities of
tuffogenous
by
small extru¬
(Lower Eocene);
material
laid down
were
(Karaj Formation).
The youngest,
Quaternary
volcanic
phase commenced with
of basic lavas. At various localities in the
region there
the
pouring
out
small, generally
are
monogenic linear volcanoes, which produced olivine trachybasalts. The Quater¬
nary volcanism is manifested most clearly, however, in the volcano Damavand,
which is at present in
Haraz
valley signify
a
an
The Damavand is
a
and
trachytes
a more
in the
springs
mixed volcano in which
pyroclastics
sequence of
a
They
incised
acid composition in the
course
are
very subordi¬
eruptions that tended from
of time.
Trachyandesites
make up most of the volcano.
The position of the dacites of Kuh-e-HarrS in the
unclear.
deeply
cooled magma hearth.
It demonstrates
nate to the extrusives.
basic towards
solfataric stage. Hot
incompletely
differ both in
of Damavand.
older, possibly
Eocene volcanism.
Chemically,
probable
It is therefore
overlying lavas
stratigraphical
section is
and in chemical composition from the
petrography
that
they belong
to
an
the rocks of the "Damavand province" fit into
determinate position. The association
can
be described
a peculiarly in¬
weakly Atlantic, with
as
a tendency towards both the Mediterranean and Pacific provincial types. Com¬
pared with typical final volcanic products, the rocks are too low in alkalies,
i.e.
too
with the
highly silicified. Their chemistry, however, can be well compared
definitely final volcanism of the Mont Dore (Auvergne).
The older phases of the Damavand are assumed to be of young Pleistocene
(early Wiirm). The younger phases, which determine the present day mor¬
phology of the volcano, certainly extend into the Holocene, as traces of a Plei¬
stocene glaciation on Damavand are missing.
The olivine trachybasalts of the linear volcanoes may also belong to the
age
younger Peistocene.
The northern part of the studied
predominantly
Central
along
and
Range" (GANSSER
the
area
is
composed exclusively of Mesozoie,
an equivalent of the "Paleozoic
HUBER, 1962). The southern boundary of this lies
Jurassic sediments and forms
Baidjan
&
thrust. The
Tertiary beds;
adjoining
it lies in the
region
area
to the south embraces Mesozoie
of the
"Tertiary
Central Zone" and the
"SouthernPaleozoic-Mesozoic Zone", which in the Damavand
parated
from each other.
valent of the "Southern
zoic and Mesozoie beds
The
region
Tertiary Zone".
are
In contrast to the
a
also exposed
gentle
fold
style.
cannot be
se¬
equi¬
Karaj section, Paleo¬
in this area.
The northern part of the area, which forms
characterized by
area
south of the Main Thrust forms the
In the
more
a
relatively high
southerly
zones
zone,
the
is
intensity
9
folding
of the
various
increases. The tectonic
thrusts, of which the
style
Most of the folds and all the thrusts
structures, points
general
as
a
is characterized
Main Thrust is the most
whole to
for the central Elburz.
a
are
the presence of
south -ver gent. The vergence of the
thrust from N to S,
Certain
by
significant.
discrepancies
as
is to be assumed in
can
be established in the
strike of the structures. The Main Thrust and most of the folds north of this
run
to
in
an
an
direction, whilst the "Southern Tertiary Zone" shows
strike, which is distinctive for the East Elburz. Thus the
ESE
ENE
Thrust cuts the anticlinal structure of Ainevarzan-Dalichai
indications
suggest
that certain disturbances
have been reactivated
10
during
the various
originated
at
orogenic phases.
a
obliquely.
an
early
tendency
Main
Various
date and
Das tertiare
Tertiarbeckens
stellt einen Auslaufer des
Kuh-Synklinorium
Zarin
Karaj-Semnan
von
entsprechend
bung begrenzt und
schief abgeschnitten. Gegen S lost
-
dar.
den
Hauptaufschie¬
palaozoisch-mesozoischen Elementen
Es wird im N durch die
-
sich das verfaltete
Synklinorium auf
und
gent
in eine grosse Monoklinale iiber. Das
allgemeine Streichen der eozanen Sedimente
entspricht demjenigen der alterenSchichtglieder. Einzig im Raum bstlich von DamavanddrehendieStreichlinienauf nordost-siidwestlichen Verlauf ab,
des Dorfes wieder auf die normale ostwestliche
Zur Zeit der
Ablagerung
der Ziarat- und
Untergrund
Reliefunterschiede aufgewiesen
rungsverhaltnisse
um
siidlich
wechseln.
zu
Karaj-Formation
der
muss
palao-
der "Siidlichen Tertiarzone" schon betracht-
zoisch-mesozoische
liche
Richtung
haben. Das
der Ziarat-Formation
am
zeigen besonders die Lage-
Nordschenkel des Antiklinoriums
Ainevarzan-Dalichai. Von W nach E schneidet das Ziarat-Konglomerat
Oberkreide, Lar-, Dalichai-, Shemshak-, Elikah-unddie Mobarak-Formationab.
von
ZUSAMMENFASSUNG
entspricht einem FaltenTeil, das Aequivalent der "Palaozoischen Zen-
Der Baustil des untersuchten Abschnittes des Elburz
gebirge.
Dabei ist der nordlichste
tralkette" imSinne vonGANSSER
undHUBER, tektonisch ruhiger
als der siidlich
an-
schliessendeBereich("Tertiare Zentralzone"und"Stidlichepalaozoisch-mesozoische Zone"), der durch das Auftretenverschiedener, z.T. bedeutender Aufschie-
bungen
charakterisiert ist. Die
Faltungsintensitat nimmt
Die Achsenebenen vieler Grossfalten fallen nach N
von
N nach S
zu.
ein, die Strukturen sind
Nordvergenz weist nur die BersudashtBeobachtungen reichen, sind die Aufschiebungen
Eine deutliche
vorwiegend siidvergent.
Antiklinale auf. Soweit die
ausnahmslos
also
siidvergent,
so
aufgeschoben sind.
Die Vergenzen deuten
dass stets altere Sedimente gegen S auf
jiingere
Serien
im ganzen
den westlichen und zentralen Elburz
von
generell
auf Schub
typisch sind,
gend nordgerichtete Bewegung
Auffallend sind
Tendenzen
fiir
annahm.
Richtung verlaufen, ergeben
zu
was
nordgerichtete Vergenzen aus,
(1960) eine vorwie¬
im Streichen der Strukturen. Wahrend
und die meisten Falten nbrdlich davon in
Hauptaufschiebung
allgemein
ost-
sich in der "Siidlichen Tertiarzone"
ostnordbstlichem Streichen, wie
kennzeichnend ist. Die
S,
fiir den J.STOCKLIN
gewisse Diskrepanzen
Hauptaufschiebung
stidbstlicher
N nach
von
anzunehmen ist. Bereits im Gebiet
STEIGER zeichnen sich gewisse Zonen durch
die fiir den Ost-Elburz
die
gesehen
es
fiir den ganzen Ost-Elburz
schneidet
beispielsweise
zoisch-mesozoischen Strukturen schief ab. Das Abweichen
vom
West-Elburz wird nbrdlich der
schon im Gebiet
deutlich. In der
die Antiklinale
Hauptaufschiebung
Damavand-Gegend weist lediglich
die
palao¬
Streichen des
STEIGER
von
von
Ziar in
ihrem bstlichsten Teil auf das Streichen des Ost-Elburz hin.
Die
Bildung
sachen in
des Vulkans Damavand ist wahrscheinlich mit tektonischen Ur-
Verbindung
schiebungen
richtungen
zu
bringen.
Er
liegt
und andererseits nahe des
des
Elburz-Gebirges
einerseits im Bereich mehrerer Auf¬
Gebietes,
in dem die
regionalen
Streich-
andern.
139