A REFINED ESTIMATE OF LAVA FLOW VOLUME OF THE DECCAN TRAPS (INDIA) USING GEOGRAPHIC INFORMATION SYSTEMS

The Deccan Traps continental flood basalts erupted onto the Indian peninsula at ~66 Ma, extending from southern India to the border of Pakistan. Previous research has been lacking in precise, spatially referenced estimates of basalt flow volumes, a metric critical for accurately determining the amount of degassing that took place over the course of the eruptions and their subsequent environmental impact. The analytical functions of the mapping software ArcGIS were used to construct high-resolution volume estimates for individual sections of some of the northern regions of the Deccan, known as the Malwa Plateau and the Mandla Lobe. Our initial findings produced a combined volume of < 2400 km³ for the whole of the Malwa. This estimate is much lower than previous estimates for total Deccan volume (~500,000 km³), but the lava flows of this sub-region are much less laterally extensive than other regions further south. To complement the work being done in the north, we also used ArcGIS to digitally trace the boundaries of the 11 major chemostratographic formations in the main Deccan region south of the Malwa. These initial findings are promising, and suggest that Geographic Information Systems (GIS) can be a key tool for interpreting the architecture of large igneous provinces (LIPs) like the Deccan Traps. We plan to integrate rock core and stratigraphic data into updated volume estimates to determine average eruption rates for individual Deccan flow formations. The work presented here will have significant consequences in understanding the pattern of gas release to the atmosphere resulting from the Deccan volcanic eruptions, and the role they may have played in the end-Cretaceous extinction and post-extinction ecosystem recovery.