抄録
Noble gases, due to their inertness and conservative behavior, have been widely applied in studies of deep Earth material cycling and planetary sciences, yet their utilization in the determination of natural gas origins and the elucidation of evolutionary mechanisms remains relatively limited. The Songliao Basin, as one of the most important faulted basins in eastern China, holds significant scientific and resource implications for understanding natural gas formation mechanisms. In this study, comprehensive abundances and isotopic compositions of noble gases were systematically measured from deep natural gas samples in the Songliao Basin, with analyses performed using advanced noble gas mass spectrometry and rigorous data quality control. The results show that noble gas abundances exhibit an inverted V-shaped distribution trend decreasing from light to heavy elements, while the ratios of ³He/⁴He, ²⁰Ne/²²Ne, ²¹Ne/²²Ne, and ⁴⁰Ar/³⁶Ar are markedly higher than atmospheric values; isotopes of Kr and Xe also display excesses relative to the atmosphere, indicating mantle-derived gas input. Integrated geochemical evidence demonstrates that deep natural gas in the Songliao Basin possesses prominent crust–mantle mixed-source inorganic origins, with varying contributions of mantle components across different structural units. This study not only reveals the compositional characteristics and genetic mechanisms of noble gases in the Songliao Basin but also provides new evidence and methodological references for the application of noble gas geochemistry in natural gas origin determination, type differentiation, and hydrocarbon resource evaluation.
