Geodynamic significance of the Cretaceous pillow basalts from North Anatolian Ophiolitic Melange Belt (Central Anatolia, Turkey): geochemical and paleontological constraints

Rojay, Fuat Bora
Altiner, SO
Onen, AP
James, S
Thirlwall, MF
The most widespread blocks within the Cretaceous ophiolitic melange (North Anatolian ophiolitic melange) in Central Anatolia (Turkey) are pillow basalts, radiolarites, other ophiolitic fragments and Jurassic-Cretaceous carbonate blocks. The pillow basalts crop out as discrete blocks in close relation to radiolarites and ophiolitic units in Cretaceous ophiolitic melange. The geochemical results suggest that analyzed pillow basalts are within-plate ocean island alkali basalts. The enrichment of incompatible elements (Nb, Ta, Light REE, Th, U, Cs, Rb, Ba, K) demonstrates the ocean island environment (both tholeiites and alkali basalts) and enriched MORB. Dated calcareous intrafills and biodetrital carbonates reveal an age span of Callovian-Early Aptian. The thin-shelled protoglobiger-inids, belonging to the genus Globuligerina, in the calcareous intrafills between pillow basalt lobes indicates a Callovian-Barremian age interval, most probably, Valanginian to Late Barremian. The volcanic and radiolarite detritus-bearing orbitolinid-Baccinella biodetrital carbonates dated as Late Barremian-Early Aptian in age, were probably deposited around atolls and have a close relationship with the ocean island pillow basalts. The results collectively support the presence of a seamount on the Neo-Tethyan oceanic crust during the Valanginian-Late Barremian and atolls during the Late Barremian-Early Aptian interval. The presence of an oceanic crust older than that seamount along the Northern Branch of Neo-Tethys is conformable with the geodynamic evolution of the Tethys. (C) 2004 Lavoisier SAS. All rights reserved


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Citation Formats
F. B. Rojay, S. Altiner, A. Onen, S. James, and M. Thirlwall, “Geodynamic significance of the Cretaceous pillow basalts from North Anatolian Ophiolitic Melange Belt (Central Anatolia, Turkey): geochemical and paleontological constraints,” GEODINAMICA ACTA, pp. 349–361, 2004, Accessed: 00, 2020. [Online]. Available: