Occurrence of abiotic methane in the eastern United Arab Emirates ophiolite aquifer

Abstract

Methane with carbon and hydrogen isotope composition diagnostic of abiotic gas related to serpentinization of peridotites has been detected for the first time in the ophiolitic aquifer in the UAE, along the Wadi Ham fault. This methane is isotopically similar to that previously reported in serpentinization-related springs in Oman, in the same Semail ophiolite nappe. Abiotic gas may be widespread in these ophiolitic rocks. Conventional thermogenic gas fields in the sedimentary basin overthrusted by the ophiolite could be “contaminated” to some extent by this abiotic gas. This may confound the accurate characterization of these thermogenic gases (origin, type of source rock type and maturity), and thus the associated petroleum system model.