龙门山造山带晚三叠世构造隆升的分段性及层序充填响应
- Received Date: 1900-01-01
- Rev Recd Date: 1900-01-01
- Publish Date: 2011-08-10
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Key words:
- sequence filling /
- western Sichuan forelandlike basin /
- Longmenshan Orogen /
- segmental uplift /
- late Triassic
Abstract: In order to knowing the relationship between the uplifting of Longmenshan Orogen and the filling characteristic of western Sichuan forelandlike basin during late Triassic, this article guided by sequence stratigraphy and sedimentology, integrated researched the outcrops, cores, then detailed studied the tectonic sequence filling characteristic in western Sichuan forelandlike Basin, founding when the setting of western Sichuan forelandlike Basin changed form marine to continental, and how was the stage. The main achievements as follow were obtained:
①From late Triassic to Jurassic, the environment of western Sichuan forelandlike basin was difference ,at the beginning ,the setting was marine, then changed to transition ,finally changed to continental environment, and the key stage was Anxian tectonic movement.
②The tectonic movement of Longmenshan orogenisc belt was eposide, the movement of each part of Longmenshan orogenisc belt was different form late Triassic to Jurassic, and the adjacent area's setting was different too.So the sedimentary models built up in different place or at the different time was difference.
③During the Ma’antang Stage(TS1BE), tectonic movement of Longmenshan orogenisc belt was weak and entire underwater ,mixed shelf is the mainly setting of the western Sichuan foreland baisn and sponge reefs found in the Anxian district. During the Xiaotangzi Stage(TS1BW), the north part of Longmenshan orogenisc belt uplifted firstly and marine delta found in the corresponding place of western Sichuan foreland basin.
During the stage of TS2BE, tectonic movement of the north part of Longmenshan orogenisc belt rivived , which led sedimentary structures with rapid filling characters forming in the northwest part of western Sichuan forelandlike basin, and tectonic movement of the middle part and the south part of Longmenshan orogenisc belt remainly quiet. In this situation, form west to east, marine delta to coastalshallow sea setting formed in the northwest Sichuan forelandlike baisn ,and coastalshallow sea to marine delta setting formed in the other place. During the stage of TS2BW, the south part of Longmenshan orogenisc belt uplifted ,too. The fragmentary material stripped form the south part and the north part of Longmenshan orogenisc belt were transported into the western Sichuan forelandlike basin. During this time ,tectonic movement of the middle part of Longmenshan orogenisc belt was not obvious, the environment of western Sichuan forelandlike basin remain transition.
When the time come to the end of TS2BW and the begin of TS3BE, the middle part of Longmenshan orogenisc belt uplifted, and the sea water dismiss form the western Sichuan forelandlike basin.After that, fluvial delta and lake were the mainly setting of western Sichuan forelandlike basin.