Thin Bed Magmatic-hydrothermal Dolomitic Exhalative Sedimentary Rocks in Santanghu Basin, Xinjiang
doi: 10.14027/j.cnki.cjxb.2017.06.001
Funds:
National Natural Science Foundation of China, No. 41572086, 41272116; Key Projects of State Key Laboratory of Continental Dynamics, No. BJ08133
- Received Date: 2017-02-14
- Rev Recd Date: 2017-04-13
- Publish Date: 2017-12-10
-
Key words:
- magmatic-hydrothermal exhalative rocks /
- carbonatite /
- dolomite /
- Lucaogou Formation /
- Sangtanghu Basin
Abstract: The Santanghu area is an intracontinental starved lacustrine rift basin from later Carboniferous to the middle Permian, and is mainly composed of interlaminated carbonate rocks and tuffaceous shale with little intervals of pyroclastic and hydrothermal exhalative rocks. This paper focuses on one special interval type which mainly contains of dolomite and smectite, and research for its forming mechanism on the basis of petrology, mineralogy and geochemistry. The simple mineral composition and euhedral crystal with partly embayed boundaries suggest an igneous origin. The rock is thin-bedded without inner stratified structure, indicating fast and mixed deposition processes from a density flow. Aggregates formed by tiny minerals may be caused by accretionary lapilli formed in clastic flow with high density and high temperature. Finally, features of geochemistry show a mainly mantle-derived origin with mixed crustal material. Comprehensively, this type of rock is deposited from subaqueous high-density pyroclastic flow fed by carbonatite eruptions, and altered by contemporaneous or later hydrothermal fluid.
| Citation: | JIAO Xin, LIU YiQun, Jin MengQi, ZHOU DingWu. Thin Bed Magmatic-hydrothermal Dolomitic Exhalative Sedimentary Rocks in Santanghu Basin, Xinjiang[J]. Acta Sedimentologica Sinica, 2017, 35(6): 1087-1096. doi: 10.14027/j.cnki.cjxb.2017.06.001
|
DownLoad: