International Conference on Gas Hydrates (ICGH) (6th : 2008)

DEEP SEA BENTHIC FORAMINIFERA AS A PROXY OF METHANE HYDRATES FROM IODP SITE 890B CASCADIA MARGIN Kumar, Amit; Gupta, Anil Kumar

Abstract

Release of methane from large marine reservoirs has been linked to climate change, as a causal mechanism and a consequence of temperature changes, during the Holocene to Late Quaternary. These inferred linkages are based primary on variation in benthic foraminifer’s singnatures. This study examines and illustrates deep sea benthic foraminifera from Holocene to Late Quaternary sample from North Pacific Ocean IODP site 890B,Cascadia Margin. Deep sea benthic foraminifera has been quantatively analyzed in samples>125 μm size fractions. Factor and Cluster analysis of the 29 highest ranked species made it possible to identify six biofacies, characterizing distinct deep sea environmental setting. The environmental interpretation of each biofacies is based on the ecology of recent deep sea benthic foraminifera. The benthic faunal record indicates fluctuating deep se condition in environmental parameter including oxygenation, surface productivity and organic food supply. The benthic assemblage show a major shift at 2 to3 kyrs BP and 6 to10.5 BP marked by major turnover in the relative abundance of species coinciding with in increasing amplitude of interstadial cycles. There are strong possibilities of methane flux in this site. Dissociation of gas hydrates and release of methane to the atmosphere could be a cause of increase in the population abundance of highly reducing environmental species, which we interpreted in our data.

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