International Geologiical Congress - Oslo 2008


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HPF-01 General contributions to paleontology and historical geology - Part 1


First evidence of Cordevolian (lower Carnian) radiolarians at the base of the Upper Antalya Nappes, Turkey


Alexandre Hungerbühler, UNIL-GSE-IGP (Switzerland)
Patrice Moix, UNIL-GSE-IGP (Switzerland)
Jean Guex, UNIL-GSE-IGP (Switzerland)
Gérard M. Stampfli, UNIL-GSE-IGP (Switzerland)
Jean Marcoux, Université Paris 7 - IPGP (France)


The Antalya Nappes crop out in southern Turkey on both sides of Antalya Bay. Their para-autochthonous sequence is made of the lower Western Beydaglar Unit (platform sediments capped by a Miocene conglomeratic flysch) overlain by the Eastern Beydaglar platform-type sequence ending with Eocene clastics.
These nappes are divided into three groups: (a) The Lower Antalya Nappe (Çatal Tepe and Dereköy units) which is characterized by Upper Triassic marls including reefal limestones, followed by a sequence of radiolarites ranging up to the Late Cretaceous. This sequence, punctuated by calciturbiditic episodes, represents upper to lower slope units; (b) The Median Antalya Nappes are three superposed units: the Alakr Çay Nappe, which is composed of Triassic to Cretaceous basinal sediments (for instance plant-bearing sandstones and the Halobia limestones for the Late Triassic interval); the Kara Dere-Sayrun Nappe, characterized by Upper Triassic (Carnian) alkaline pillow-lavas; the Ophiolitic Nappe, capped by Middle Maastrichtian (Siderolites sp.) ophiolitic debris; (c) The Paleozoic to Upper Cretaceous Upper Antalya Nappes comprise three distinct units: the Kemer Gorge, the Bakrl and the Tahtal nappes. The Kemer Gorge and Bakrl nappes occupy the lowest position. The Tahtal Nappe occupies the highest position in the tectonic pile and rests upon an Upper Cretaceous olistostrome (with ophiolitic debris) on top of the Kemer Gorge Unit.
For the first time, we present a lowermost Carnian radiolarian assemblage from a new unit situated at the base of the Çrk dag. This new unit is always underlying the Upper Antalya Nappes, and is likely to act as their tectonic sole. It can be traced laterally over kilometers and is homogenous in composition. The main lithologies are: late Early Triassic gypsum and anhydrite with versicolor marly limestones (Claraia sp. and Eumorphotis sp.), turbiditic sandstone with plant remains (Anisian?), Upper Ladinian radiolarite (Daonella sp.) and red siliceous limestone, Norian pelagic limestone (Halobia sp.). The newly described assemblage is from a dismembered outcrop of red siliceous limestone and chert (GPS 36°41'10'', 30°27'59''). One sample is a red chert which contains the following species: Tritortis kretaensis kretaensis (KOZUR & KRAHL); Canoptum cucurbita (SUGIYAMA); Canoptum levis TEKIN; Nodotetrasphaera cive (SUGIYAMA); Kahlerosphaera parvispinosa KOZUR & MOSTLER; Spongoserrula sp. and Muelleritortis sp.. This assemblage is clearly indicative of the Cordevolian Tritortis kretaensis Zone.


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