NISCAIR Online Periodicals Repository

NISCAIR ONLINE PERIODICALS REPOSITORY (NOPR)  >
NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Geo-Marine Sciences (IJMS) >
IJMS Vol.38 [2009] >
IJMS Vol.38(4) [December 2009] >


Title:  Effect of Miocene paleoceanographic changes on the benthic foraminiferal diversity at ODP site 754A (southeastern Indian Ocean)
Authors: Rai, Ajai Kumar
Maurya, Abhayanand Singh
Keywords: Benthic Foraminifera
Diversity
Indian Ocean
Miocene
Oceanography
Issue Date: Dec-2009
Publisher: CSIR
Abstract: Miocene deep sea benthic foraminiferal diversity at ODP site 754A, in the southeastern Indian Ocean was examined in the present study. Paleoceanographic and paleoclimatic changes were inferred based on the above study. Species diversity was measured in terms of Shannon-Weaver Index [H(S)], Hurlbert’s Diversity Index (S100), Alpha Index (α) and Equitability (E’). Values of S100 show more positive correlation with H(S) and α value. All diversity parameters show almost similar pattern during the study interval. Present study infers that the changing trophic level has much influence on the faunal diversity. More diverse fauna of late early Miocene to early middle Miocene along with low δ18O and high δ13C values reflect warm and stable bottom waters with low food supply. This corresponds to the Miocene climatic optimum. This was also an interval of global warming and reduced Antarctic ice-sheet volume. Significant decline in diversity and d13C values along with abrupt increase in d18O values at ~ 14 Ma indicate cold, relatively less oxygenated and unstable bottom waters with increased food supply due to higher surface productivity. Development of thermal gradient between low and high latitudes in response to the expansion of Antarctic ice-sheet during 15-12.5 Ma was responsible for increased upwelling and high surface productivity. Decrease in faunal diversity at ~7 Ma onwards along with low δ13C and high δ18O values corresponds with the Chron-6 negative Carbon shift, expansion of west Antarctic ice-sheets and lowering of sea level.
Page(s): 423-431
ISSN: 0975-1033 (Online); 0379-5136 (Print)
Source:IJMS Vol.38(4) [December 2009]

Files in This Item:

File Description SizeFormat
IJMS 38(4) 423-431.pdf338.17 kBAdobe PDFView/Open
 Current Page Visits: 624 
Recommend this item

 

National Knowledge Resources Consortium |  NISCAIR Website |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2012 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 568768 since 06-Feb-2009  Last updated on 14-Aug-2014Webmaster: nopr@niscair.res.in