Preliminary study of evaporites deposition from the Mesozoic to Cenozoic in southwestern Tarim Depression
Sang Hong1, Cao Yangtong2,3, Zhu Lichun1, Zhang Hua3, Zhang Liang1
Yao Fojun3, Zeng Changmin1, Jiao Pengcheng3, Jiang Hong1, Liang Hua1
1 Research Institute of Petroleum Exploration & Development,Tarim Oilfield Branch Company,
PetroChina,Korla 841000,Xinjiang
2 School of Earth Science and Resources,Chang′an University,Xi′an 710054,Shaanxi
3 MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,CAGS,Beijing 100037
Based on the previous data,the fieldwork on evaporite outcrops,the halite sedimentary characteristics and the salt mineralogy study,it preliminarily discussed the distribution,the occurrence strata,and the salt mineral assemblages and genesis of the Meso-Cenozoic evaporites in the southwestern Tarim Depression. The Lens-shaped halite mainly distributed along the front of west Kunlun Mountain,and usually contained maroon or celadon muddy gravel. The lithology of halite is the same as that of the lower member of Tuyiluoke Formation. So,the halite is speculated to form during the regression of late depositional period of Tuyiluoke Formation,and its strata belonged to the upper member of Tuyiluoke Formation. The laterally-discontinuous halite lenses indicated the possible existence of multiple sub-depressions of palaeo-salt-lakes,which were evaporated and formed halites under an arid climate. The evaporite minerals were mainly halite and gypsum,as well as some polyhalite and glauberite. The polyhalite in gypsum may be the products of primary gypsums replaced by late potassium-rich brine;while the secondary glauberites,discovered on the halite surface in Well Wubo 1,were probably formed during the supply of calcium-rich groundwater to the salt lakes after its precipitation of halites.
