Abstract Views :214 |
PDF Views:2
Authors
Affiliations
1 Paleontology Division, Marine Wing, Geological Survey of India, 8th Floor, Bhuvigyan Bhavan, DK-6, Salt Lake City, Kolkata 700091, IN
2 Department of Earth Sciences-Marine Geology, Goteborg University,
Box 460, SE-40530, Goteborg, SE
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No Spl Iss 3 (2006), Pagination: 407-423
Abstract
A good correlation between the relative abundance of G ruber and estrmated sea surface temperatures (SST's) is documented for the Late Quaternary sequence rn five deep-sea cores from the northern 90°E Rldge, SE Bay of Bengal (6-9°N latitude, water depths 2492 - 3033 rn) The relative abundance of G ruber is high during the warmer perids of Holocene, and low during the colder Late Pleistocene surface temperatures Sea surface temperatures estimated from the planktonic foraminiferacl census data using Artificial Neural Networks (ANN'S) have upper and lower limits of 29 9 and 27 8 °C respectively for summer and wlnter durig the Mid-Holocene and 27 5 °C and 26 5 °C during the Last Glacial Maximum (LGM) The relative abundance data of G ruber estimated SST's, stable isotope composition of G ruber from adjacent locations ra drocarbon dates and lnferred oxygen isotopic ages, have been used to demonstrate the reliability of this species as an lndicator of Late Quaternary climate change in the SE Bay of Bengal Flve climatic events (El-E5), correlatable with the Late Quaternary marine and terrestrial records of the lndian subcontinent, have been identified on the basis of depletion and abundance of G ruber Three cold events (El, E3 and E5), characterized by a relativee decrease in the abundance of G ruber, are centered around 18±1, 11±1 and 2 25°0 75 ka B P The intervening warm events (E2 and E4), showing a relative increase in the abundance of G ruber, are documented around 14 5°0 5 and 6° ka B P This study also records the first direct faunal evidence of the equivalent of the Younger Dryas cooling phase, identified as event E3 in the Bay of Bengal The end of the E3 cold event at around 10 ka B P has been identified as the Pleistocene-Holocene boundary.
Keywords
Bay of Bengal, G ruber, Late Quaternary, Paleoclimate, SST's, Artificial Neural Networks, Younger Dryas, Last Glacial Maximum.
