Systematic and Temporal Geochemical Changes in the Upper Deccan Lavas: Implications for the Magma Plumbing System of Flood Basalt Provinces

Hoyer P, Haase K, Regelous M, Fluteau F (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Geochemistry Geophysics Geosystems American Geophysical Union (AGU)

Book Volume: 24

Article Number: e2022GC010750

Journal Issue: 2

DOI: 10.1029/2022GC010750

Abstract

Large Igneous Provinces (LIPs) are unusual volcanic events in which massive amounts of melt (∼106 km3) erupt in relatively short time periods (<106 years). Most LIP magmas have undergone extensive fractional crystallization and crustal contamination, but the crustal magmatic plumbing systems and the processes triggering eruptions are poorly understood. We present new major and trace element and radiogenic isotope data for 43 individual lava flows from a continuous 1,200 m thick stratigraphic profile through the upper, most voluminous part of the Deccan LIP (Bushe to Mahabaleshwar Formations). Eruption rates for this section are constrained by published paleomagnetic directions and absolute U-Pb ages for zircons from weathered flow tops exposed in the profile. We find four magmatic sequences each lasting ∼104–∼105 years during which major and trace element compositions change systematically, followed by an abrupt change in geochemistry at the start of a new sequence. Within each sequence, the MgO content and proportion of crustal contamination decrease progressively, indicating a continuous replenishment of the associated magma reservoirs with less contaminated but more evolved melts. These geochemical signatures are best explained by repeated episodes of melt recharge, mixing, and eruption of variably evolved magmas originating from relatively small magma reservoir located in different crustal levels.

Authors with CRIS profile

Patrick Hoyer Lehrstuhl für Endogene Geodynamik Karsten Haase Lehrstuhl für Endogene Geodynamik Marcel Regelous Lehrstuhl für Endogene Geodynamik

Related research project(s)

Formation and evolution of flood basalt magmas – combining geochemical data with the magnetic stratigraphy of the Deccan large igneous province March 1, 2020 - Feb. 28, 2022

Involved external institutions

Paris Institute of Earth Physics / Institut de Physique du Globe de Paris (IPGP) FR France (FR)

How to cite

APA:

Hoyer, P., Haase, K., Regelous, M., & Fluteau, F. (2023). Systematic and Temporal Geochemical Changes in the Upper Deccan Lavas: Implications for the Magma Plumbing System of Flood Basalt Provinces. Geochemistry Geophysics Geosystems, 24(2). https://dx.doi.org/10.1029/2022GC010750

MLA:

Hoyer, Patrick, et al. "Systematic and Temporal Geochemical Changes in the Upper Deccan Lavas: Implications for the Magma Plumbing System of Flood Basalt Provinces." Geochemistry Geophysics Geosystems 24.2 (2023).

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