MAPPING THE RATE OF CARBON MINERALIZATION IN OMAN OPHIOLITES USING SENTINEL-1 InSAR TIME SERIES

Interferometric Synthetic Aperture Radar (InSAR) measurements reveal ground deformation following a rainfall event in the Samail Ophiolite in Oman. Due to the absence of usual tectonic and hydrologic forcings, we hypothesize that deformation is a result of chemical reactions and associated fracturing in the subsurface. When the ultramafic rocks in the ophiolite are exposed to air and water, they undergo carbonation which increases the rock volume and fractures the rock, resulting in observable ground surface uplift. A pilot study using 41 Sentinel-1 SAR images between 2016/11/15 and 2018/03/22 shows up to 4 cm of uplift in the several weeks following a major rainfall event, suggesting that carbonation is limited by rainfall. The uplift signal eventually recedes back to the noise level thus a longer time series with more rainfall events will better confirm this hypothesis. An eventual InSAR time series from 2015-present and an associated groundwater table model may improve the current estimates of CO2 captured by the carbonation, and its rate, in ultramafic rocks.