The Signature of Metasomatized Subcontinental Lithospheric Mantle in the Basaltic Magmatism of the Payenia Volcanic Province, Argentina
Name
Geochem Geophys Geosyst - 2022 - Chilson‐Parks - The Signature of Metasomatized Subcontinental Lithospheric Mantle in the.pdf
Description
Published version
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10.7 MB
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Checksum (MD5)
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Author(s)
Chilson‐Parks, Benjamin H
Calabozo, Fernando M
Saal, Alberto E
Wang, Zhengrong
Mallick, Soumen
Petrinovic, Ivan A
Frey, Frederick A
Date Issued
January 5, 2022
Journal
Geochemistry, Geophysics, Geosystems
Publisher
American Geophysical Union
Citation
Chilson-Parks, B. H., Calabozo, F. M., Saal, A. E., Wang, Z., Mallick, S., Petrinovic, I. A., & Frey, F. A. (2022). The signature of metasomatized subcontinental lithospheric mantle in the basaltic magmatism of the Payenia volcanic province, Argentina. Geochemistry, Geophysics, Geosystems, 23, e2021GC010071.
Version
Final published version
Abstract
The Payenia region of Argentina (34.5–38°S) is a large Pliocene-Quaternary volcanic province of basaltic compositions in the Andean Cordillera foothills representing the northernmost extent of back-arc volcanism in the Andean Southern Volcanic Zone (SVZ). Although the chemical diversity of the Payenia basalts has been characterized previously, the processes and sources responsible for such variation remain controversial. Here, we report new whole-rock major and trace element concentrations, Sr-, Nd-, Hf-, and Pb-isotope ratios and high-precision olivine oxygen-isotope ratios in a suite of 35 alkaline basalts from Payenia. These lavas have major and trace elements that define a compositional range from arc-influenced to intraplate signature. Variable crustal contamination and/or recent slab-derived inputs inadequately account for elemental and isotopic systematics and spatial compositional variations of Payenia lavas. We present a simple forward model indicating that early metasomatism and subsequent melting of the metasomatized subcontinental lithospheric mantle (SCLM) has significantly contributed to the Payenia lava compositional range. Isotopic ingrowth calculations of radiogenic Sr, Nd, Hf, and Pb suggest that the SCLM metasomatism occurred at 50–150 Ma, consistent with the timing of the breakup of Gondwana and the development of the proto-Pacific Andean arc. Variations in δ18Oolivine values from modeled melts indicate that the metasomatism and melting within the SCLM can fractionate oxygen isotopes even when the metasomatizing melt has MORB-like δ18O values, providing a different explanation for the low-δ18O signatures observed in continental arc settings.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution-NonCommercial-NoDerivatives
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DOI of Published Version
https://doi.org/10.1029/2021gc010071
