Research Information System
26e édition de la Réunion des Sciences de la Terre, Lille, France, 22 - 26 October 2018, pp.316, (Summary Text)
The sedimentary sequences of the Karaburun peninsula belong to the Bornova Flysch zone. The paleogeographic affinity of the latter is still in debate; for some it is more related to the Menderes Massif, for others to the Sakarya Zone. Radiolarian assemblages are important to understand the paleogeographic history of the Bornova Flysh Zone. Altough many studies exist about Mesozoic carbonate platform sequences cropping out on the Karaburun Peninsula, Meso- zoic and Upper Paleozoic radiolarian cherts, resent in the area, remain largely unexplored. In this study, relatively well preserved radiolarian assemblages were recovered from three outcrops displaying sequences of radioalria cherts: the Kalecik, Ildir and Karareis sections. The Kalecik section is situated in the northern part of the Karaburun Peninsula, near the Kalecik town; it displays a ca. 15 m-thick block of red bedded cherts and it is regarded as being part of the Bornova mélange (sensu Erdogan). It yielded a radiolarian assemblage characterized by Hexasaturnalis minor (BAUMGARTNER), Transhsuum brevicostatum gr. (OZVOLDOVA) and Tritrabs sp.cf. T. casmaliaensis (PESSAGNO), which may be correlated with the Bathonian – Kimmeridgian interval. This block represents radiolarian ooze accumulation in the Izmir-Ankara Ocean; it is likely that it was incorporated in an accretionary prism formed during the latest Cretaceous. The Ildir section crops out in the western part of the Karaburun Peninsula, around the Ildir village; it displays a 10 meter-thick sequence of made of thinly-bedded fine-grain greenish-brownish sandstone beds alternating with blackish shales and cherts. The Karareis section displays a sequence made of 30 cm-thick black chert beds; it is located in the Gerence bay of western Karaburun peninsula. The sedimentary sequences of the Ildir and Karareis sections are assigned to the Dikendaği formation; they delivered Devonian radiolarian assemblages, characterized by the presence of Palaeoscenidium tabernaculum AITCHISON and Trilonche davidi (HINDE). They represent radiolarian ooze accumulation in a fine siliciclastic depositional setting, possibly at the distal part of a Gondwanan margin facing Paleotethys. It is likely that they were incorporated in the Bornova Flysch zone during the Triassic.