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Timing and preservation mechanism of deglacial pteropod spike from the Andaman Sea, northeastern Indian Ocean

DRS at CSIR-National Institute of Oceanography

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Title Timing and preservation mechanism of deglacial pteropod spike from the Andaman Sea, northeastern Indian Ocean
 
Creator Sijinkumar, A.V.
Nath, B.N.
Gupta, M.V.S.
Rao, B.R.
 
Subject MOLLUSCS
PALAEO-STUDIES
 
Description The aragonite compensation depth (ACD) fluctuated considerably during the last glacial until the Holocene with a dominant pteropod preservation spike during the deglacial period, which is prominently seen in three well-dated cores covering the Andaman Sea, northeastern Indian Ocean. The precise time period of the preservation spike of pteropods is not known but this knowledge is crucial for stratigraphical correlation and also for understanding the driving mechanism. Isotopic and foraminiferal proxies were used to decipher the possible mechanism for pteropods preservation in the Andaman Sea. The poor preservation/absence of pteropods during the Holocene in the Andaman Sea may have implications for ocean acidification, driven by enhanced atmospheric CO2 concentration. Strengthening of the summer monsoon and the resultant high biological productivity may also have played a role in the poor preservation of pteropods. The deglacial pteropod spike is characterized by high abundance/preservation of the pteropods between ~19 and 15 cal. ka BP, associated with very low atmospheric CO2 concentration. Isotope data suggest the prevalence of a glacial environment with reduced sea surface temperature, upwelling and enhanced salinity during the pteropod preservation spike. Total planktic foraminifera and Globigerina bulloides abundances are low during this period, implying a weakened summer monsoon and reduced foraminiferal productivity. Based on the preservation record of pteropods, it is inferred that the ACD was probably deepest (>2900 m) at 16.5 cal. ka BP. The synchronous regional occurrence of the pteropod preservation spike in the Andaman Sea and in the northwestern Indian Ocean could potentially be employed as a stratigraphic marker.
 
Date 2015-08-24T09:41:00Z
2015-08-24T09:41:00Z
2015
 
Type Journal Article
 
Identifier Boreas, vol.44(2); 2015; 432-444
http://drs.nio.org/drs/handle/2264/4755
 
Language en
 
Rights This is a preprint of an article published in [Boreas, vol.44(2); 2015; 432-444]” and an electronic link to the Journal’s WWW site, http://dx.doi.org/10.1111/bor.12099
 
Publisher John Wiley