近日，中国石油大学（华东）刘可禹团队，报道了华南埃迪卡拉纪碳酸盐岩储层中流体包裹体记录的古油藏快速热解，提供了对瓜达鲁普末期大灭绝的启示。相关论文于2024年12月3日发表在《地质学》杂志上。

据介绍，与大火成岩省定位相关的热成因温室气体排放，先前被假设为全球变暖的一个可能因素，而全球变暖引发了地质历史上的大规模物种灭绝，由于缺乏有力证据，这一问题仍未得到充分理解。

研究团队提供了保存完好的矿物学、流体包裹体和地球化学记录，结果表明，四川盆地中部（华南）埃迪卡拉纪碳酸盐岩储层中，大量古油藏的快速热解与峨眉山大火成岩省的喷发有关，该火山喷发可能导致了瓜达鲁普末期的灭绝(ca.259Ma)。

研究人员认为古油藏的热解作用发生在约ca.258.4±7.3Ma，与峨眉山大火成岩省侵位有关，导致温度和压力迅速升高，估计瞬时储层压力接近岩石静压的两倍。

随着温度的持续上升，地层压力随之下降，储层中大量超压甲烷沿着断层或岩浆管道迅速排放到大气中，最终引发了瓜德鲁普末期的灭绝事件。研究强调了与大火成岩省相关的热成因甲烷的大量排放，对地球历史上的气候变化、碳循环和生物进化的重要性。

附：英文原文

Title: Rapid pyrolysis of paleo-oil pools recorded by fluid inclusions in an Ediacaran carbonate reservoir, southern China: Implications for the end-Guadalupian mass extinction

Author: Peng Yang, Zhijun Jin, Keyu Liu, Xuesong Lu, Changwei Li, Lili Gui, Jianliang Liu, Junjia Fan, Shunyu Wang, Yang Xu

Issue&Volume: 2024-12-03

Abstract: Thermogenic greenhouse gas emission associated with large igneous province emplacement has previously been hypothesized as a possible contributor to global warming that triggered mass extinctions in Earth’s history, yet this issue remains inadequately understood due to a lack of robust evidence. We present a well-preserved mineralogical, fluid inclusion, and geochemical record indicating a rapid pyrolysis of vast paleo-oil pools in an Ediacaran carbonate reservoir in the central Sichuan Basin (southern China) relating to the eruption of the Emeishan large igneous province that potentially contributed to the end-Guadalupian extinction (ca. 259 Ma). We conclude that the pyrolysis of the paleo-oil pools occurred at ca. 258.4 ± 7.3 Ma associated with the emplacement of the Emeishan large igneous province, causing a rapid increase of temperature and pressure with an estimated transient reservoir pressure of nearly twice that of the lithostatic pressure. A subsequent drop in the formation pressure occurred as the temperature continued to rise, indicating that massive over-pressured methane in the reservoir had been rapidly emitted into the atmosphere along faults or magmatic pipes, ultimately contributing to the end-Guadalupian extinction. Our study highlights the significance of massive emission of thermogenic methane related to large igneous provinces for climate change, carbon cycling, and biological evolution in Earth’s history.

DOI: 10.1130/G52452.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G52452.1/650447/Rapid-pyrolysis-of-paleo-oil-pools-recorded-by