Reunion plume associated flood basalt volcanism on the northwestern continental margin of India and related tectonics

Abstract

Late Cretaceous Deccan flood basalt province in central-western India was formed by the R�union plume and continues to attract global attention due to its enormous volume and volcanic eruption straddling the K-T boundary.Furthermore, despite having a profound impact on crustal architecture of the Northwestern Continental Margin of India (NWCMI), very little information about the flood basalt extension in the NWCMI is reported.Therefore, it is necessary to document areal extent and volume of the flood basalt on the NWCMI.In this study, bathymetry, gravity, magnetic and seismic data are integrated to delineate the spatial extent and volume of offshore flood basalt.Crustal architecture, and the role of R�union plume in evolution of the NWCMI are also discussed.According to the findings of this study, R�union plume associated flood basalt has carpeted the entire NWCMI up to the Laxmi Ridge.It is also found in the Laxmi Basin, regardless of its crustal nature (continental/oceanic), which is still debated.The results revealed that the flood basalt occurs at depth of 500-7500 m and its thickness varies from few meters to 3900 m.The study also discovered several magmatic intrusions into the crust, which altered initial crustal configuration of the NWCMI.The study revealed an extrusive area of ~5.37 � 105 km2 and a volume of ~6.59 � 105 km3 of lava flow in the NWCMI.The estimated offshore surface area covered with the R�union plume associated flood basalt is 7% larger than the Deccan trap-covered surface area on the adjacent onshore region.