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Pandey D.K.,National Institute of Oceanography of India | Pandey A.,Center for Climate Change Research | Rajan S.,National Institute of Oceanography of India
Natural Resources Research | Year: 2011

The Deccan basalts in central western India are believed to occupy large onshore-offshore area. Using geophysical and geological observations, onshore sub-surface structural information has been widely reported. On the contrary, information about offshore structural variations has been inadequate due to scarcity of marine geophysical data and lack of onshore-offshore lithological correlations. Till date, merely a few geophysical studies are reported that gauge about the offshore extent of Deccan Traps and the Mesozoic sediments (pre-Deccan). To fill this gap in knowledge, in this article, we present new geophysical evidences to demonstrate offshore continuation of the Deccan volcanics and the Mesozoic sediments. The offshore multi-channel seismic and onshore-offshore lithological correlations presented here confirm that the Mesozoic sedimentary column in this region is overlain by 0.2-1.2-km-thick basaltic cover. Two separate phases of Mesozoic sedimentation, having very distinctive physical and lithological characteristics, are observed between overlying basaltic rocks and underlying Precambrian basement. Using onshore-offshore seismic and borehole data this study provides new insight into the extent of the Deccan basalts and the sub-basalt structures. This study brings out a much clearer picture than that was hitherto available about the offshore continuation of the Deccan Traps and the Mesozoic sediments of Kachchh. Further, its implications in identifying long-term storage of anthropogenic CO2 within sub-basalt targets are discussed. The carbon sequestration potential has been explored through the geological assessment in terms of the thickness of the strata as well as lithology. © 2010 International Association for Mathematical Geology.

Pandey A.,Center for Climate Change Research | Pandey A.,National Institute of Oceanography of India | Mishra R.,National Institute of Oceanography of India
Journal of Earth Science | Year: 2013

High-precision, clay sediment oxygen and hydrogen isotopes analyses of Pleistocene-Holocene deep-sea sediments from the Bay of Bengal (BOB) are presented for the first time. Our study shows that the major source of sediments in the study area, since the last ∼25 000 years, is likely to be the Higher Himalayan crystalline rocks. Further, the study of these stable isotope data displays the variation of southwest monsoon (SWM) in the BOB region since the last ∼25 000 years and the cause behind the variation has been interpreted. The δ18O values of the clay sediments are compared with δ18O values of the BOB seawater. This comparison shows that the clay sediment δ18O values of the studied sediment cores temporally vary along with the changes in strength of the SWM. Based on the changes in the clay sediment δ18O values of the studied sediment, we evaluate the variance in the SWM since the last 25 000 years in the BOB. Our results are consistent with previous work in the region based on other proxies. To evaluate the factors influencing the intensity of the SWM since the last glacial maxima, we conducted comparative analyses of the studied clay sediment δ18O values with δ18O values in the Greenland ice cores (GISP2) and Tibetan ice cores (Guliya). The results from this comparative study show that large-scale changes in the intensity of the SWM since 25 000 years are affected by the climate oscillations of the Northern Hemisphere, but rapid and abrupt fluctuations in the SWM seem to be controlled by the amount of snow cover in the Tibetan Plateau. © 2013 China University of Geosciences and Springer-Verlag Berlin Heidelberg.

Pandey D.K.,National Institute of Oceanography of India | Pandey A.,Center for Climate Change Research | Rajan S.,National Institute of Oceanography of India
Natural Resources Research | Year: 2010

The subsurface imaging using conventional seismic reflection technique is challenging in areas where high velocity rocks such as basalts are underlain by low velocity rocks. The seismic image quality worsens in the presence of intercalated sediments within the basaltic layers. In the recent years, the multicomponent seismic exploration technique has drawn great attention because it reduces the ambiguity in seismic imaging, enlarges the S-wave information, and improves the prediction and identification of reservoir fluids. Improvements in sub-basalt imaging techniques could hold highly significant geologic implications such as resource exploration and identifying permanent geochemical trapping potential (such as for carbon sequestration studies). In this article, we examine the possibility of utilizing mode-converted (P-SV) waves for sub-basalt imaging as well as likely complicacies one may expect in such processes. © 2010 International Association for Mathematical Geology.

Adger W.N.,Center for Climate Change Research | Adger W.N.,University of Melbourne | Barnett J.,Center for Climate Change Research | Barnett J.,University of Melbourne | And 4 more authors.
Global Environmental Politics | Year: 2011

The dangers that future climate change poses to physical, biological, and economic systems are accounted for in analyses of risk and increasingly figure in decision-making about responses to climate change. Yet the potential cultural and social impacts of climate change have scarcely been considered. In this article we bring the risks climate change poses to cultures and social systems into consideration through a focus on places-those local material and symbolic contexts that give meaning and value to peoples' lives. By way of examples, the article reviews evidence on the observed and projected impacts of climate change on the Arctic and Pacific island atoll nations. It shows that impacts may result in the loss of many unique natural and cultural components of these places. We then argue that the risk of irreversible loss of places needs to be factored into decision-making on climate change. The article then suggests ways forward in decision-making that recognizes these non-market and noninstrumental metrics of risk, based on principles of justice and recognition of individual and community identity. © 2011 by the Massachusetts Institute of Technology.

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