石油勘探与开发2026，Vol.53Issue(2)：345-356,12.DOI:10.11698/PED.20250511
特提斯域关键构造转换期地质事件控制下的白云石化作用
Dolomitization controlled by geological events during the critical tectonic transition of the Tethyan domain:A case study from the Permian Maokou Formation in eastern Sichuan Basin,SW China
摘要
Abstract
Focusing on the dolomites within the Permian Maokou Formation in eastern Sichuan Basin,this study integrates petrographic observation,geochemical analysis and in-situ U-Pb dating to constrain the timing of dolomitization and trace the sources of dolomitizing fluids,analyze the intrinsic links among geological events during the tectonic transition of the Paleo-Tethys to Neo-Tethys oceans,strike-slip faulting and dolomitization,so as to reveal the dolomitization mechanism of the Maokou Formation.Three types of matrix dolomites occur in the Maokou Formation in eastern Sichuan Basin,with U-Pb ages indicating three dolomitization phases at(260.6±6.8)-(265.1±2.4),(244.0±11.0)-(247.7±6.0),and(220.6±8.5)-(221.4±7.8)Ma,respectively.Geochemical data indicate distinct fluid origins for each phase of dolomitization.Three geological events and the resulting three episodes of faulting during the tectonic transition from Paleo-to Neo-Tethys Ocean are key controlling factors of three phases of dolomitization.Specifically,the Middle Permian Emeishan magmatism activated the Houba-Peng'an-Fengdu strike-slip fault zone and induced thermal anomalies,promoting thermal convection between contemporaneous seawater and the Lower Silurian siltstone aquifer,and initiating the first phase of dolomitization.During the Middle Triassic,oblique closure of the Mianlüe Ocean induced transtensional faulting,and density-driven downward migration of residual evaporitic seawater and brines from evaporates in the Lower-Middle Triassic facilitated the second phase of dolomitization.The Late Triassic continental collision between the South China Block and North China Block induced transpressional faulting,driving the upward migration of brines within the Lower Siluria to mix with residual evaporitic seawater in the Lower-Middle Triassic,thus supplying the magnesium source for the third phase of dolomitization.A strike-slip fault-controlled dolomitization model is established,providing new insights into the formation mechanisms of dolomite reservoirs in the Tethyan domain.关键词
激光原位U-Pb定年/白云石化作用/二叠系茅口组/四川盆地/峨眉岩浆活动/勉略洋斜向闭合/古—新特提斯洋构造转换Key words
laser in-situ U-Pb dating/dolomitization/Permian Maokou Formation/Sichuan Basin/Emeishan magmatism/oblique closure of the Mianlue Ocean/tectonic transition from Paleo-to Neo-Tethys Ocean分类
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朱彦先,何治亮,郭小文,张昊,李龙..特提斯域关键构造转换期地质事件控制下的白云石化作用[J].石油勘探与开发,2026,53(2):345-356,12.基金项目
国家自然科学基金项目"特提斯演化控制下的油气差异富集机理与勘探领域"(92255302) （92255302）
