Geological Society of America

T329 Asthenosphere to Atmosphere: Tectonics, Topography, and Climate

Wednesday, 25 October 2017
1:30 PM - 5:30 PM
Room 609

RIDGE OUTGASSING AND MELT PRODUCTION FROM 4GA TO PRESENT

Paper number: T329-10
Program: Technical Sessions
Time: 3:45 PM – 4:00 PM

Authors

Jocelyn Fuentes Presenting Author
Harvard University, Cambridge, MA
John Crowley
Natural Resources Canada, Ottawa, ON
Rajdeep Dasgupta
Rice University, Houston, TX
Jerry X. Mitrovica
Harvard University, Cambridge, MA

Abstract

The majority of Earth’s volcanism occurs at ocean ridges via decompression melting. This process exerts a strong control on the mantle and surface volatile contents throughout Earth history. In this study, we investigate mantle temperature, ridge melt production, and ridge CO₂ outgassing from 4 Ga to present by coupling an analytical mantle convection model (Crowley and O’Connell 2012) with a recent petrologic model of peridotite melting in the presence of CO₂ (Dasgupta et al. 2013). By taking advantage of the computational efficiency of the convection model, we simulate time-dependent convection with a large suite of realistic mantle and lithospheric parameters to produce a full range of possible thermal histories. We only accept models which evolve from stagnant-lid convection to mobile-lid convection in order to be consistent with previous geodynamic modeling and geochemical studies (i.e. Condie et al. 2016, Debaille et al. 2013). The presence of volatiles in the mantle leads to deeper, low degree melting. This effect, combined with higher temperatures sustained during the phase of stagnant-lid convection, has a significant effect on the total mass of CO₂ outgassed (as well as other volatiles), with major implications for early Earth climate and its continued evolution.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-305605

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