(10) The principal proponent of the theory is Thomas Gold (1920-2004), who achieved fame for his 1992 paper "The Deep Hot Biosphere" which proposed an abiogenic
origin of coal, oil, and gas deposits.
For the Kidd Creek samples, the pronounced isotopic depletion of [C.sub.2]-[C.sub.4], and the lack of a thermogenic type enrichment trend for [C.sub.1]-[C.sub.4], are consistent with an abiogenic kinetically-controlled polymerization reaction.
Isotope geochemistry was the key to determining that the hydrocarbon and hydrogen gases deep in Precambrian Shield rocks are produced not by conventional mechanisms but by abiogenic reactions.
Glasby, "Abiogenic origin of hydrocarbons: An historical overview," Resource Geology, vol.
Krayushkin, "Deep-seated abiogenic origin of petroleum: From geological assessment to physical theory," Reviews of Geophysics, vol.
However, this conclusion is now being reconsidered in the light of recent research demonstrating that abiogenic
hydrocarbon formation via chemical reactions between water, dissolved inorganic carbon and minerals is not only capable of producing reduced organic carbon, but that this organic carbon is strongly isotopically depleted with respect to its inorganic source.
In general, the C[H.sub.4]-rich hydrothermal fluids may come from three ultimate sources: (1) abiogenic
origin derived from the mantle [33, 34]; (2) abiogenic
origin derived from postmagmatic alteration by Fischer-Tropsch type synthesis [35-37]; (3) incorporation of thermally decomposed organic material (thermogenesis) or/and products from microbial processes (bacteriogenesis) [38-41].
Recent, and ongoing, studies at Kidd Creek have yielded valuable insights into understanding abiogenic
versus biogenic sources of methane in the Earth's subsurface (Fig.
Fischer-Tropsch synthesis of methane at the Baogutu reduced porphyry copper deposit, western Junggar, NW-China," Geochimica et Cosmochimica Acta, vol.
Wang, "Serpentinization, abiogenic
organic compounds, and deep life," Science China Earth Sciences, vol.
The Upper Paleozoic ([P.sub.1]x-[P.sub.1]x) alkane gas in the Hangjinqi area in northern Ordos Basin mainly displays positive carbon and hydrogen isotopic series (Figures 4 and 5) with [[delta].sup.13][C.sub.1] value higher than -30[per thousand] (Figure 3(b)), suggesting the typically biogenic gas rather than the abiogenic