MagNetZ With Priyeshu Srivastava (2022/06/15) - Understanding role of the Deccan flood volcanism
Channel: MagNetZ
Date: 2022-06-15

Continental and marine records of paleoclimatic changes during the late Maastrichtian and early Danian: Understanding role of the Deccan flood volcanism

The video is also available for download at: https://earthref.org/ERDA/2533/
and can be referenced with the doi: 10.7288/V4/ERDA/2533

Title: Continental and marine records of paleoclimatic changes during the late Maastrichtian and early Danian: Understanding role of the Deccan flood volcanism
Author: Priyeshu Srivastava from Universidade de São Paulo, Brazil

The temporal link between large igneous provinces (LIPs) magmatism and global environmental changes including mass extinctions have led to extensive studies on cause-and-effects relationship between them. The volatile released from LIPs magmatism (SO2, CO2, HCl) have been hypothesized to have both short term effects (e.g., cooling associated with sulphate aerosols, acid rain, ozone depletion) on time scale of several years to long term environmental changes (e.g., warming associated with CO2) up to several 100 ka. One such well-studied LIP is Deccan flood volcanism (DFV) which erupted between ~66.3 and 65.4 Ma, and is temporally linked with the Cretaceous-Paleogene (K/Pg) boundary mass extinctions at ~66 Ma. The K/Pg boundary mass extinction has also been linked to Chicxulub asteroid impact, which often argued for a primary driver of mass extinction. In this work, we attempt to understand both regional and global climatic changes in response to these volatiles. We first show sub-aerial alteration characteristics of different color weathering profiles (known as boles) trapped between two successive lava flows in the Deccan Traps, followed by the sedimentary marine records from the South Atlantic. Geochemical and rock magnetic characteristics of the boles show weathering signatures suggestive of near neutral pH conditions and locally changing redox, some of which may have largely escaped post-eruptive acidic precipitation possibly due to the transport of acidic gases into the upper atmosphere (stratosphere) under semi-arid conditions. These volatiles transported to the upper stratosphere may have been distributed globally. The loss of magnetic signals in marine sedimentary sequences prior to the K/Pg boundary, often interpreted as a dissolution signal from DFV induced acidifications, was found in the South Atlantic. The oxygen isotopes on bulk carbonate sample showed significantly decreased values (warming) in the early Danian coinciding with eruptions of the DFV, accompanied by the Hg and Pb anomalies (markers for volcanism). These new results improve our understanding of the volcanism induced changes in global climate. 


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00:00 - Intro
01:28 - Presentation
33:16 - Questions
41:38 - Announcements