The natural gas carbon and hydrogen isotopic compositions in Tarim Basin show that methane δD in Kuche petroleum system ranges from-185‰ to-156‰ (most < -170‰),ethane δD ranges from-139‰ to-113‰.

The reverse series of carbon isotope composition of natural gas in this area is mainly caused by the same-type and different-source gas or the same source and different-phase gas in humic-type organic ma.

The molecular compositions and compound-specific stable carbon isotope compositions of individual n-alkanes from surface sediments of the East China Sea(ECS) mud areas including the coastal mud area,the southwest mud area to Cheju Island,and the Northern Okinawa Trough were analyzed using gas chromatography/mass spectrometry(GC/MS) and gas chromatography/isotopic ratio mass spectrometry (GC/IRMS).

The stable carbon isotope compositions in plant leaves can be used to provide information of original carbon in soil organic matter and paleo-ecological evolutions, based on the good relationship between the stable carbon isotope compositions and water use efficiency in plants or plant productivity to some extent.

Abnormal carbon isotopic compositions in organic matter of lacustrine source rocks close to sea

Purpose of this study is to reveal the variation characteristics of kerogen during thermal evolution by determining the residual rate of kerogen and the carbon isotopic composition of residual kerogen at (different thermal) (evolution) stages, thus providing evidence of carbon isotope for quantitative identification and assessment of effective gas source rock.

The carbon isotopic composition of saturated and aromatic hydrocarbons, the oil isotopic curve and individual saturated hydrocarbon isotopic composition are studied in this paper.