Toggle Main Menu Toggle Search

Open Access padlockePrints

Molecular and carbon isotopic compositions of gas inclusions of deep carbonate rocks in the Tarim Basin

Lookup NU author(s): Dr Paul Farrimond


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Gaseous components of gas inclusions in deep carbonate rocks (>5700 m) from the Tacan 1 well were analyzed by online mass spectrometry by means of either the stepwise heating technique or vacuum electromagnetism crushing. The carbon isotopic compositions of gases released by vacuum electromagnetism crushing were also measured. Although the molecular compositions of gas inclusions show differences between the two methods, the overall characteristics are that gas inclusions mainly contain CO2, whilst hydrocarbon gases, such as CH4, C2H6 and C3H8, are less abundant. The content of CO is higher in the stepwise heating experiment than that in the method of vacuum electromagnetism crushing, and there are only minor amounts of N2, H2 and O2 in gas inclusions. Methane δ13C values of gas inclusions in Lower Ordovician and Upper Cambrian rocks (from 5713.7 to 6422 m; -52‰-63‰) are similar to those of bacterial methane, but their chemical compositions do not exhibit the dry character in comparison with biogenic gases. These characteristics of deep gas inclusions may be related to the migration fractionation. Some deep natural gases with light carbon isotopic characteristics in the Tazhong Uplift may have a similar origin. The δ13C1 values of gas inclusions in Lower Cambrian rocks (7117-7124 m) are heavier (-39‰), consistent with highly mature natural gases. Carbon isotopic compositions of CO2 in the gas inclusions of deep carbonate rocks are similar (from -4‰ to -13‰) to those of deep natural gases, indicating predominantly an inorganic origin. Copyright by Science in China Press 2004.

Publication metadata

Author(s): Zhou S, Wang X, Meng Z, Li Y, Farrimond P, Li L, Duan Y

Publication type: Article

Publication status: Published

Journal: Science in China, Series D: Earth Sciences

Year: 2004

Volume: 47

Issue: 5

Pages: 445-452

Print publication date: 01/05/2004

ISSN (print): 1006-9313

ISSN (electronic):


DOI: 10.1360/02yd0323


Altmetrics provided by Altmetric