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四川盆地古近系柳嘉组以发育沙漠沉积为特征,是青藏高原东缘古近纪风成沙丘富集带的重要组成部分。采用碎屑锆石LA-ICP-MS年代学方法,首次研究了柳嘉组碎屑锆石年龄组成,分析了该组的沉积物来源,探讨了物源区区域构造热事件在柳嘉组碎屑锆石年龄谱中的反映。获得的53组碎屑锆石U-Pb有效年龄表明,柳嘉组的物源主要集中在1 811Ma~1 677Ma、865Ma~705Ma、457Ma~384Ma、306Ma~240Ma及218Ma~129Ma五个区间,物源区主要为扬子陆块西缘。综合研究表明,柳嘉组碎屑锆石存在5个较为明显的峰值1 773Ma±82Ma、800Ma±5Ma、298Ma±4Ma、252Ma±3Ma及201Ma±2Ma,记录了扬子陆块西缘古元古代—中生代5次较为重要的构造热事件。
The Paleogene Liujia Formation in Sichuan Basin is characterized by the development of desert sediments and is an important part of the enrichment belt of the Paleogene aeolian dune in the eastern margin of the Qinghai-Tibet Plateau. The detrital zircon LA-ICP-MS chronological method was used to study the age composition of zircon detrital zircon in the Liujia Formation for the first time. The source of sediments in this group was analyzed, and the tectonic thermal events in the provenance area were discussed. Reflection of age spectrum of zircons. The obtained zircon U-Pb ages of 53 detrital zircons show that the provenances of the Liujia Formation are mainly concentrated in five intervals of 1811Ma ~ 1677Ma, 865Ma ~ 705Ma, 457Ma ~ 384Ma, 306Ma ~ 240Ma and 218Ma ~ 129Ma The source area is mainly the western edge of the Yangtze block. The comprehensive study shows that there are five obvious peaks of the detrital zircons in the Liujia Formation: 1773Ma ± 82Ma, 800Ma ± 5Ma, 298Ma ± 4Ma, 252Ma ± 3Ma and 201Ma ± 2Ma. The paleoproterozoic- Mesozoic five more important tectonic thermal events.