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Evolution of the Molecular Structure of Middle Devonian Sedimentary Organic Matter in Yunnan and Its Petroleum Geological Significance

middle Devonian,Hydrocarbon generation,Plant terrestrialization

Theme 3: Earth-Life Co-evolution Through Time > Session 3c: Life-Mineral Interactions during the Plant Terrestrialization

Evolution of the Molecular Structure of Middle Devonian Sedimentary Organic Matter in Yunnan and Its Petroleum Geological Significance

Chenxi Wang ^a, Yu Liu ^a,*, Xingzhe Wang ^a, Jiayue Feng ^a and Le Liu <sup>a

a</sup> College of Geoscience and Survey Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

*Corresponding author: liuyu@cumtb.edu.cn

Abstract: The Devonian marked the early stage of plant colonization on land, during which terrestrial plant structures and compositions differed significantly from later periods. As a result, the molecular structure and hydrocarbon generation characteristics of Devonian terrestrial sedimentary organic matter exhibit distinct features. This study focuses on kerogen-rich sedimentary organic matter from the Middle Devonian Haikou Formation. Through organic petrological and geochemical analyses, the unique microscopic composition of the organic matter was clarified, and its hydrocarbon generation potential was evaluated. Hydrocarbon generation characteristics and model variations during thermal evolution were investigated using gold-tube pyrolysis experiments. Furthermore, molecular structure characterization experiments (¹³C-NMR, FT-IR) were employed to systematically analyze the molecular structure of the organic matter and its transformation during thermal evolution. This study systematically reveals the hydrocarbon generation potential and the evolution of molecular structures of kerogen-rich sedimentary organic matter in the Devonian Haikou Formation, providing theoretical insights for the effect of plant colonization on land on the petroleum resources.