Abstract

Surface geochemical prospecting studies comprising of Gas Chromatographic determination of adsorbed light gaseous hydrocarbons and determining the signatures of stable carbon isotopes of methane in near surface soil samples has been carried out in Kutch-Saurashtra to evaluate the potential of the area for hydrocarbon resources. It is based on the concept that the light gaseous hydrocarbons (methane through butanes) from oil and gas reservoirs migrate to the surface and gets adsorbed to the near surface soils and sediments which on desorption by acid extraction technique and quantification gives an idea of spatial distribution of hydrocarbons. The concentration (ppb) of methane (C1 ) varied from 4-291, ethane (C2 ) from 0-84, propane (C3 ) from 0-37, i-butane (iC4 ) from 0-5and n-butane (nC4 ) from 0-4 suggesting that the generation of hydrocarbons has taken place in the basin. The carbon isotopic (VPDB) signatures of methane ranged from 32.2