Oxygen isotopic composition of Albian-Turonian foraminifera from Cauvery Basin, India: Evidence of warm sea-surface temperature

• Main Authors: DAS GUPTA, K, SARASWATI, PK, KRAMAR, U, RAVINDRAN, CN, STUBEN, D, BERNER, Z
• Format: Article in Journal/Newspaper
• Language: English
• Published: GEOLOGICAL SOC INDIA 2007
• Subjects: Southeastern India; Ocean; Tertiary; Eocene; Record; Palaeotemperature; Stable Isotopes; Foraminifera; Cretaceous; Cauvery Basin; Tamil Nadu; Planktonic foraminifera
• Online Access: http://dspace.library.iitb.ac.in/xmlui/handle/10054/7866; http://hdl.handle.net/10054/7866

The clays of Karai Formation (Uttatur Group) contain well-preserved planktonic and benthic foraminifera of Albian-Turonian age. The pristine tests of planktonic and benthic foraminifera were analyzed for their oxygen isotopic compositions. The delta O-18 values of planktonic foraminifera, comprising Whiteinella archaeocretacea, Marginotruncana sp., Rotalipora reicheli, Praeglobotruncana stephani and Globigerinelloides sp. indicate the maximum near-surface temperatures of 29 degrees C. The bottom water temperature, estimated on benthic foraminiferal species Gyroidinoides sp., Quadrimorphina sp., Gavelinella sp., Lenticulina sp. and Pleurostomella sp., is about 21 degrees C. This is in agreement with the palaeoclimatic conditions inferred on fossil assemblages.