Arkell.1956.Jurassic..

ASIA MINOR 349
beginning with the Burdigalian, was laid as a continuous blanket over
most of Asia Minor and Cyprus. At least in Cyprus, deposition was
interrupted by thrusting at the end of the Miocene, followed by renewed
subsidence. Finally, in the late Pliocene there was regional doming
and extensive block-faulting, accompanied by volcanism in Anatolia,
doubtless reverberations of the major orogeny that was taking place at
that time in the Zagros ranges of Persia and of the Pliocene folding in
the Tellian Atlas.
Lias and Middle Jurassic of Anatolia
Lias occurs in the centre and east of northern Anatolia in three distinct
groups of small outcrops, each group separated by about 130 miles from
the other. The most westerly group lies to the north and west of Ankara
and includes the celebrated localities Yakacik (Jakadjik) and Kesiktash
(Kessik-tash) described by Pompeckj (1897) and Vadasz (1913). About
130 miles ENE. of this is another group north of Amasiya, in the Akdag
range (Akdag = White Mountain), including the well-known locality
Merzifun (Meister, 1913; Pia, 1913; Gugenberger, 1929). About the
same distance ESE. is the third and most easterly group, north of Erzincan,
in which are the more scattered localities of Reksene, Deredolu and
Bayburt (Otkun, 1942, Ketin, 1951, Baykal, 1951) (plate 20).
The survival and exposure of these small fragments of a once continuous
marine formation seem to be purely fortuitous and provide an objectlesson
in the possibilities of complete removal. The outcrops near
Ankara form part of a complicated mosaic of faulted ancient and Neogene
volcanic rocks, and Jurassic and Cretaceous and Tertiary sediments.
The outcrops in the Akdag range consist of long, narrow wedges
('Schuppen') folded in between ridges of Permo-Carboniferous Fusulina
limestone; those of the eastern group, near Erzincan, are completely
surrounded by metamorphic rocks. The facies of all is similar, consisting
largely of hard or marly, reddish, compact limestones reminiscent of the
Adneth Limestone of the Alps, but generally more argillaceous. Cephalopods
are by far the most abundant fossils, and among them there is a
marked preponderance of Phylloceratina and Lytoceratina. Crinoids
also abound, often attached to ammonite shells; brachiopods are common,
and there are bands of Gryphaea. At Merzifun sponges are frequent,
indicating an almost clear-water environment. The ammonites represent
a mixture of predominantly North-Alpine with Mediterranean (especially
Apennine) forms, and others that are local or eastern.
According to the analyses by Pia and Gugenberger, however, the
Akdag Lias is all Pliensbachian with Domerian, mainly of the Jamesoni
Zone, with Margaritatus Zone also represented, but nothing either older
or younger. At Kesiktash, near Ankara, Sinemurian is present, for the
ammonites denote Bucklandi Zone and Margaritatus Zone. In the eastern
group of occurrences, Otkun (1942) is able to show the presence of Sinemurian
(Bucklandi, Raricostatum and 'Armatum' Zones), Pliensbachian
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