TOF‐SIMS Study of the Hydrocarbon‐generating Potential of Mineral‐Bituminous Groundmass

Abstract

The TOF-SIMS fragment peak ascription of organic and inorganic ions of mineral-bituminous groundmass of Jurassic source rocks in the Turpan-Hami and Junggar basins was studied by using the high-resolution Time of Flight Secondary Ion Mass Spectrometer (TOF-SIMS). The characteristics of spectrum distribution and constitution of fragment ions of the mineral-bituminous groundmass are discussed; then the methods of evaluating its hydrocarbon-generating potential are developed. In addition, the typical parameters, X , , , Y , and Z,,, for indicating the hydrocarbon-generating potential of mineral-bituminous and other organic matter in source rocks are put forward to reflect the aliphatic, oxygenous, and aromatic structures. It is confirmed by Rock-Eva1 that these parameters are significant in evaluating hydrocarbon generation. Moreover, the detection of the nitrogenous and oxygenous fragment ion, CH,NO,', in the mudstone formed in semi-deep lakes and in the carbargilite formed in the arms of lakes reflects the fact that microbes take an active part in biologic degradation.