MagNetZ With Katie Bristol (2024/04/03) - Fast and Furious: Magnetic Drift
Channel: MagNetZ
Date: 2024-04-08

Fast and Furious: Magnetic Drift - Using Quantitative Paleosecular Variation Techniques to Quantify the Tempo of Large Igneous Provinces

The video is also available for download at: https://earthref.org/ERDA/2733/
and can be referenced with the doi: 10.7288/V4/ERDA/2733

Title: Fast and Furious: Magnetic Drift - Using Quantitative Paleosecular Variation Techniques to Quantify the Tempo of Large Igneous Provinces
Author: Katie Bristol from University of Florida, USA

Large Igneous Provinces (LIPs) are areas where exceptionally large volumes of volcanic rocks have been emplaced over a relatively short geologic timeframe. The study of LIPs is crucial due to their association with fundamental Earth processes such as mantle plumes and continental rifting. Moreover, LIPs tend to coincide with dramatic events in Earth history including mass extinctions, rapid climate shifts, and major environmental perturbations. Therefore, constraining their chronological framework is essential to research questions in fields such as volcanology, tectonics, paleoclimate, and more. Existing geochronological methods can determine time between individual lava flows if the ages of the flows do not fall within the margin of error from one another (10’s of ka). For example, in the Deccan Traps LIP many dates overlap across hundreds of meters of volcanic stratigraphy, necessitating an additional chronometer. Analysis of paleomagnetic directions between flows in conjunction with detailed knowledge of the stratigraphy can be used to construct a relative eruption history. To predict eruption rates quantitatively, we developed a novel technique that uses existing geochronological data in combination with paleomagnetic data, geochemistry, and lava flow morphology. This forward modelling approach compares magnetic data in a Bayesian inversion framework with synthetic eruption histories produced by downsampling real secular variation records. The result is a set of predictions which can assess the eruption tempo based on the most probable number of eruption pulses, eruption duration, and hiatus durations between pulses. In addition to directional data, we also present preliminary paleointensity estimates for these samples. Future work will refine these predictions by incorporating cosmogenic data to estimate surface exposure durations between flows. This approach is particularly advantageous as it incorporates information from multiple subdisciplines and improves overall resolution of estimates for multiple facets of LIP emplacement tempo. Overall, this method represents a valuable tool for determining the eruptive histories of LIPs.


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00:00 - Intro
00:56 - Presentation
24:18 - Questions
38:47 - Announcements