Apatite fission-trackand Re-Os geochronology of the Xuefeng uplift, China: Temporal implications fordry gas associated hydrocarbon systems
Apatite fission-trackand Re-Os geochronology of the Xuefeng uplift, China: Temporal implications fordry gas associated hydrocarbon systems
复制标题
中国雪峰隆起的磷灰石裂变径迹和铼锇年代学：对干气伴生烃系统的时间意义
作者：
Xiang Ge;Chuanbo Shen;David Selby;Dafei Deng;Lianfu Mei
在复杂的构造背景下，油气演化在时间和空间上都极具挑战性。在这里，我们调查了雪峰隆起西缘（中国南部），它记录了多个和长期的构造和生烃事件。低成熟沥青（A型）记录了这一初始生油时间，其产生的Re-Os沥青年龄约为1.25年。430马，与盆地模型和ca。405 Ma沥青Rb-Sr年龄。相比之下，磷灰石裂变径迹（AFT）数据产生了相当年轻的日期，反映了燕山造山带从西北（约1000年）的时间和构造演化。150 Ma）向东南方向（约。70 Ma）。最年轻的AFT年龄与雪峰隆起的西缘相吻合，那里产出高成熟度沥青（B型），产生约1000个AFT年龄。70 Ma Re-O日期。Re-Os年龄和AFT年龄表明，燕山运动的最后阶段以及由此推断的干气生成的停止都发生在大约1000年。70马。本研究的Re-Os数据意味着Re-Os计时器可以帮助限制石油生成和次生和/或更成熟的烃过程的时间（例如，热裂解和/或气体生成）。
Hydrocarbon evolution is extremely challenging to determine, both temporally and spatially, in complex tectonic settings. Here we investigate the western margin of the Xuefeng uplift (southern China), which records multiple and protracted tectonic and hydrocarbon-generation events. This timing of initial oil generation is recorded by low-maturity bitumen (type A), which yields an Re-Os bitumen date of ca. 430 Ma, consistent with basin models and a ca. 405 Ma bitumen Rb-Sr date. In contrast, apatite fission-track (AFT) data yield considerably younger dates that reflect the timing and tectonic evolution of the Yanshan orogeny from the northwest (ca. 150 Ma) to the southeast (ca. 70 Ma). The youngest AFT date coincides with the western margin of Xuefeng uplift, where high-maturity bitumen (type B) occurs that yields a ca. 70 Ma Re-Os date. The Re-Os and AFT dates imply that both the last stage of the Yanshan orogeny and, by inference, the cessation of dry gas generation, occurred ca. 70 Ma. The Re-Os data of this study imply that the Re-Os chronometer can aid in constraining the timing of oil generation and secondary and/or more mature hydrocarbon processes (e.g., thermal cracking and/or gas generation) in hydrocarbon systems worldwide.