Deccan Syneclise Basin is considered geologically prospective for
oil and gas reserves; however, a major part of the basin is covered by the Deccan Traps, hindering the exploration of Mesozoic hydrocarbon targets. Surface
geochemical prospecting, based on micro-seepage of hydrocarbons from subsurface accumulations, could be advantageous in such areas. Surface
geochemical prospecting method was applied in Deccan Syneclise for evaluation of hydrocarbon resource potential of the basin. The
gas chromatographic analyses of adsorbed s
oil gasses showed the presence of C
1 to C
4 hydrocarbons. The concentrations of adsorbed s
oil gasses ranged for methane (C
1) = 1 to 483 ppb, ethane (C
2) = 1 to 83 ppb, propane (C
3) = 1 to 38 ppb, butane (nC
4) = 1 to 60 ppb
and ¦²C
2 + = 1 to 129 ppb, respectively. The scatter plots between C
1 and C
4 components depict linear trend indicating that all the
gasses are derived from the same source.
The carbon isotope composition of adsorbed methane was measured using Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS). The values for methane ¦Ä13C1 varied from ?#xA0;39.9 to ?#xA0;19.9?versus the Vienna PeeDee Belemnite (VPDB). The carbon isotope ratio distribution pattern represents isotopic characteristics pertaining to hydrocarbon gasses derived from thermogenic sources. The propane oxidizing bacteria (POB) ranged between 1.0 ¡Á 102 and 12.8 ¡Á 105 cfu/g of soil. The adsorbed light gaseous hydrocarbons and propane oxidizing bacterial anomalies found in and around Aurangabad, Ahmednagar, Shirdi, Akola, Bhusawal and Indore areas are considered to be promising for future hydrocarbon research and exploration.