Paleobathymetry of Submarine Lavas in the Samail and Troodos Ophiolites: Insights From Volatiles in Glasses and Implications for Hydrothermal Systems

Belgrano, Thomas M.; Tollan, Peter M.; Marxer, Felix; Diamond, Larryn W. (2021). Paleobathymetry of Submarine Lavas in the Samail and Troodos Ophiolites: Insights From Volatiles in Glasses and Implications for Hydrothermal Systems. Journal of Geophysical Research: Solid Earth, 126(7) American Geophysical Union 10.1029/2021JB021966

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Hydrostatic pressure exerted by the ocean water column fundamentally influences magmatic and hydrothermal processes in submarine volcanic settings and is therefore an important parameter to know when investigating such processes. Currently, there are few reliable methods for reconstructing past ocean depths for ancient volcanic terranes. Here, we develop and test an empirically calibrated statistical approach for determining paleodepths of eruption from the concentrations of H2O and CO2 dissolved in volcanic glasses, utilizing the well-defined pressure-dependent solubility of these volatiles in silicate melts. By comparing newly determined and published glass compositions from the Samail and Troodos ophiolites with sedimentary and fluid inclusion evidence, we propose that the Samail lavas erupted at ocean depths of ∼3.4 km, and the Troodos lavas at ∼4.1 km. These depths are 1–2 km deeper than those assumed in most previous studies of hydrothermal activity in the two ophiolites. These high depths imply high hydrostatic pressures within the underlying oceanic crust. Such pressures may have allowed convecting hydrothermal fluids to attain significantly higher temperatures (e.g., >450°C) than in typical modern ocean ridge hydrothermal systems during metal leaching in the crust and metal precipitation in seafloor sulfide deposits.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Belgrano, Thomas M. and Diamond, Larryn W.

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

2169-9356

Publisher:

American Geophysical Union

Language:

English

Submitter:

Larryn William Diamond

Date Deposited:

10 Mar 2022 10:48

Last Modified:

10 Mar 2022 10:56

Publisher DOI:

10.1029/2021JB021966

BORIS DOI:

10.48350/166726

URI:

https://boris.unibe.ch/id/eprint/166726

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