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Turkish Journal of Earth Sciences

Authors

MANOLYA SINACI

DOI

10.3906/yer-1011-19

Abstract

Some nannoplankton species are sensitive to water temperatures. While Coccolithus pelagicus and Reticulofenestra gelida indicate cooler water conditions, the genera Discoaster and Sphenolithus and Calcidiscus leptoporus are indicative of warmer water environments. This paper focuses on relative fluctuation of sea water temperatures during the Middle and Late Miocene, emphasised by cold and warm nannofossil changes in abundance in 2 wells. At the A-1 well in the Middle Miocene, the total abundance of cooler water species is 45%, while that of the warmer species is 3%. During the Late Miocene, the total abundance for cooler water species decreases to 34%; in contrast, the total abundance of warmer species increases up to 7%. Thus, the cooler sea water temperature during the Middle Miocene becomes warmer in the Late Miocene. From the A-2 well, the total abundance of Middle Miocene cooler water species is 46%, but that of the warmer species is 11%. The total abundance of cooler water species decreases to 41%, and the total abundance of warmer species increases to 18% in the Late Miocene. Based on nannofloral fluctuation, we may thus deduce that water surface temperature increased from the Middle to the Late Miocene. Data on nannofossil abundance from the Miocene Adana Basin show that sea water temperature was cooler in the Middle Miocene, and water temperatures increased in the Late Miocene.

First Page

247

Last Page

263

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