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Estimation of Volatile Degassing from Younger Deccan Traps Basaltic Volcanism across the Cretaceous-Paleogene Boundary using Geochemical, Petrological and Vesiculation Analyses

Ritwick Sen 1,2, Margherita Polacci1, Margaret Hartley1, Mike Burton1, Saibal Gupta2

  • Affiliations: 1Department of Earth and Environmental Sciences, The University of Manchester, Manchester, UK; 2Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur, India

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 225

  • Programme No: 3.17.12

  • Theme 3 > Session 17

Abstract

Large-scale volcanism associated with the Deccan Traps coincided with a major extinction event at the Cretaceous-Paleogene (K-Pg) boundary, approximately 66 million years ago. Volatile emissions from these extensive basaltic lava flows likely played a pivotal role in driving climate variations during this period. In this study, the volatile budget of Deccan Traps lava flows erupting at the K-Pg boundary is measured using various geochemical and petrological techniques on the tholeiitic lava flows of the younger Wai Subgroup. Melt inclusions preserved in plagioclase and clinopyroxene phenocrysts are analysed using Electron Probe Micro Analyser (EPMA) and Nano-scale Secondary Ion Mass Spectrometry (Nano-SIMS) to provide quantitative estimates of pre-eruptive volatile content in the magma. In addition, bulk-rock trace element concentrations in the basalt, measured using wet chemistry Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), serve as proxies for particular volatile species to empirically calculate the volatile contents in the lava flows. In addition, trace volatile content in clinopyroxene grains, measured using SIMS, is used to constrain the volatile concentration of the equilibrium Deccan melt based on experimentally derived partitioning coefficient (KD) values. Finally, the vesicle size distribution and number density plots of Deccan lava flow crusts, generated using 3D X-ray Computed Microtomography, offer insights into the syn- and post-eruptive degassing mechanisms and efficiency of the lava flows. This project aims to integrate the quantified volatile budget of lava flows with vesiculation analysis to develop a degassing model, enabling further investigation into the extent of climate modification caused by the Deccan Traps eruption.