Biao Jin* and Ping’an Peng

Guangzhou Institute of Geochemistry Chinese Academy of Sciences

jinbiao@gig.ac.cn

Position specific isotope analysis (PSIA) of thermogenic propane provides a valuable tool to investigate propane’s origin, fate, and mechanisms of formation¹. However, understanding the link between the observed carbon PSIA signals of propane and the associated underlying mechanisms still requires a more sophisticated model. Our study developed a mathematical framework to simulate position specific carbon isotopologues of propane and its precursors based on their bond-cleavage reaction pathways². The model allows integrating multiple signals, including temperature, and isotopic signatures of mother compounds, and is validated by precisely reproducing the experimental PSIA data obtained during cracking of different kerogens. Also, the initial carbon isotopic signatures as well as the initial fraction of two possible mother compounds in kerogen are determined. Thus, our model serves as a novel tool for quantitive analysis of PSIA signals of thermogenic propane to investigate fate of propane in subsurface.

[1] Zhang, Li, Jiang & Xiong (2022). Organic Geochemistry 166: 104379.

[2] Jin & Peng (2024), The Innovation Geoscience 2(1): 100054.