FIRST DISCOVERY OF MIDDLE TOURNAISIAN CONODONTS IN THE GRIOTTE-TYPE NODULAR PELAGIC LIMESTONES, ISTANBUL AREA, NW TURKEY

The uppermost layers of the Ayineburnu member of the Büyükada Formation in the Istanbul-Gebze area are represented by Griotte-type pelagic nodular limestones. They yielded conodont elements (Bispathodus stabilis and Siphonodella lobata) that can identify the interval from the upper part of the sandbergi Zone through the isosticha- Upper crenulata Zone - middle Tournaisian - Early Carboniferous. This is the first middle Tournaisian conodont record published from an autochthonous succession in the Istanbul Terrane, NW Turkey. This level characterizes the very last carbonate deposition and is followed by lydites and black siliceous shales and finally by the accumulation of flysch-type deposits during the late Tournaisian and early Visean, that mark the onset of Variscan events to the north of the Istanbul Terrane. A correlation with the Lower Carboniferous successions in the easterly-located Zonguldak area suggests that Istanbul and Zonguldak terranes were in quite different palaeogeographic positions during this time interval

CARBONIFEROUS CONODONT BIOSTRATIGRAPHY AND LATE PALAEOZOIC DEPOSITIONAL EVOLUTION IN SOUTH CENTRAL IRAN (ASADABAD SECTION - SE ISFAHAN)

Asadabad section in Central Iran is one of the most complete sequences so far described across the Carboniferous of Iran. The stratigraphic and biostratigraphic data on the sediments overlying the Devonian carbonate platform give evidence about the duration of shallow water depositional evolution. There are thirty productive levels with conodonts in the Carbonifeous section ranging in age from early Tournaisian to the top of Bashkirian (Lower expansa - sulcata to sinuosus zones). There is scarce evidence about the elongatus Zone presence - Late Pennsylvanian. Sulcata to anchoralis-latus conodont zones in Shishtu Formation and muricatus to sinuosus Zone and a possible elongatus Zone in Sardar Formation have been indentified. These conodont zones are reported for the first time in that area. A crinoidal limestone - key bed horizon, is traceable in the studied area as well as in other parts of Iran. It is Early Pennsylvanian-Bashkirian in age and is correlated to sinuatus-minutus Zone. The studied Shishtu and Sardar Formations (Carboniferous) as well as Vazhnan and Surmaq Formation (Permian) in the section belong to marine near shore sedimentation with many macrofaunal remains.

Silurian Graptolite, Conodont and Cryptospore Biostratigraphy of the Guluc Section in Eregli, Zonguldak Terrane, NW Anatolia, Turkey

The studied Guluc section of the Silurian Findikli Formation is situated on the western bank of Guluc Creek in Eregli, NW Anatolia, Turkey, in the eastern part of the Zonguldak Terrane. The Guluc section consists of 3 sedimentary packages: greenish grey limy siltstones, 5-7 m thick (1), overlain by an irregular alternation of black shales and clayey limestones, about 15 m thick (2), and a 6-7 m thick succession of mainly siltstones and sandy limestones (3). A combined biostratigraphy based upon graptolites, cryptospores and conodonts indicates that Package 1 is of Llandovery (Rhuddanian, Aeronian and/or early Telychian) age, Package 2 and Package 3 are of late Wenlock-early Ludlow (Homerian and Ludfordian) age. Graptolites in packages 2 and 3 indicate the presence of the Cyrtograptus lundgreni, Neodiversograptus nilssoni and Lobograptus scanicus graptolite biozones. The Ozarkodina crassa Biozone occurs in the lower Gorstian (Ludlow). The specific features of the Guluc section (lithological changes, condensation, stratigraphic gap, change in graptolite diversity) are related to the global model of Silurian T-R cycles. The Silurian Findikli Formation in the Guluc section, about 20 m thick, represents a condensed lithological succession which differs significantly from the coeval thick, stratigraphically widespread black shales and siltstones of the same formation in the Zonguldak and Istanbul terranes. Sixteen cryptospore species are described and their stratigraphic and geographic distributions are summarised

New biostratigraphical data from the Ordovician of Bulgaria

7 páginas, 2 figuras.-- Edited by: G. L. Albanesi / M. S. Beresi / S. H. Peralta.-- Proceedings of the International Symposium on the Ordovician System. San Juan - Argentina 2003.Peer reviewe

New conodont and palynological data from the Lower Palaeozoic in Northern Camdag, NW Anatolia, Turkey

Two main thrust slices in the Camdag area ( NW Anatolia), were informally named the Southern and Northern Camdag units. New micropaleontological and palynological data about the Ordovician, Silurian and Devonian in the Northern Camdag have allowed a better understanding of the early Palaeozoic evolution of this critical area between the Istanbul Terrane in the west and the Zonguldak Terrane in the east. The Middle Ordovician age obtained from the conodont-bearing limestone band within the Aydos formation in this study is in agreement with the data from the Zonguldag Terrane. Acritarch evidence suggests a Late Ordovician age of the upper part of Aydos formation

New Age Data From The Tectonostratigraphic Units Of The Istranca "Massif" In Nw Turkey: A Correlation With Se Bulgaria

The Istranca Crystalline Complex in NW Anatolia and SE Bulgaria includes structural units that differ in lithostratigraphy, metamorphism, age and structural position. They are collectively named as the "Istranca nappes" comprising from bottom to top the Sarpdere, Mahyadag. and Dogankoy Nappes. The Sarpdere Nappe consists of Lower Triassic arkosic metasandstones with slate interlayers, followed by Middle to Upper Triassic carbonates and an alternation of Upper Triassic clastics and carbonates. The Mahyada. g Nappe comprises a low-grade metamorphic Late Paleozoic-Triassic carbonate-siliciclastic sedimentary succession. The Dogankoy Nappe includes Precambrian?-Paleozoic metasediments, intruded by Late Carboniferous-Early Permian calc-alkaline granitoids. Its Triassic cover comprises metaclastics and metacarbonates. The Istranca nappes were juxtaposed at the end of the Triassic and transgressively covered by Lower Jurassic coarse clastics, followed above by Middle to Late Jurassic carbonates, black shales and carbonate-siliciclastic sedimentary succession. The phosphate concretions in black shales yielded radiolarian assemblages indicating Late Bajocian-Early Bathonian, Early Bathonian and Early Kimmeridgian ages. These nappes and their Jurassic cover are unconformably overlain by the Cenomanian-Santonian volcano-sedimentary successions intruded by Santonian-Campanian Derekoy-Demirkoy intrusive suite. The preliminary data suggest that the Variscan basements of the Mahyadag and Sarpdere Nappes were juxtaposed prior to the Triassic and overridden by the Dogankoy Nappe of possible Rhodopean origin from S to N during the Cimmerian compressional events.WoSScopu