DISCOVERY OF THE OLDEST (UPPER LADINIAN TO MIDDLE CARNIAN) RADIOLARIAN ASSEMBLAGES FROM THE BORNOVA FLYSCH ZONE IN WESTERN TURKEY: IMPLICATIONS FOR THE EVOLUTION OF THE NEOTETHYAN IZMIR-ANKARA OCEAN

Abstract

Diverse upper Ladinian to middle Carnian radiolarian faunas have been obtained from different ribbon cherts blocks and tectonic slices of the Izmir- Ankara Suture Complex and the marginal sediments of the Tauride-Anatolide platform within the Bornova Flysch Zone, western Turkey. Four isolated samples with late Ladinian, early Carnian, late early Carnian, early middle Carnian ages and one continuous section with late Ladinian to late early Carnian age were considered. As a result of taxonomic studies, sixty-six taxa from different families were defined from these time intervals, definition of sixteen taxa remained in open nomenclature were given and one new species (Pseudostylosphaera mostleri) was determined. The radiolarian ages obtained indicate an upper Ladinian to upper lower Carnian deepening of the Middle Triassic Tauride-Anatolide carbonate platform. Combined with regional geological data this event is interpreted to reflect the initial opening of the Neotethyan Izmir-Ankara oceanic seaway.