| 柴达木盆地大浪滩盐矿床基本特征及形成机理 |
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| THE FEATURES AND GENESIS OF THE DALANGTAN SALT DEPOSIT IN THE QAIDAM BASIN |
| The Dalangtan Basin, with a typical inland saline lake deposition of MgSO4 subtype, is a subbasin of the Qaidam Basin in Qinghai Province. Some K-Mg saline minerals such as bischofite, carnallite, sylvite, leonite, leoweite, epsomite, etc. can be found in the basin.The evolution of and salt deposition in the basin were principally controlled by the neotectonic movement. The basin was separated into a series of depressions by neotectonism in the Late Tertiary and hence started the period of salt deposition. As a result of successive tectonic movement, the basin got more closed, the materials supplied from outside gradually decreased, the salinity of the lake water increased cyclically, and finally the basin dried up. While the center of sedimentation migrated from the east to the west and. then to the north, the typical phase change series of carbonate-sulphate-K-Mg salt minerals was formed.The geochemical variations of sediments partly reflect the affect of tectonic movement during the evolution of the basin.The brine in the salt-bearing strata of the Quaternary was mainly derived from the inland river and/or lake, and also was partly mixed up with deep circulating water in some places. The insufficient K-Mg supply and more than 33 desalinations occurring during the evolution of the basin resulted in incomplete saline deposit phases and inconsiderable content of K-Mg salt minerals in the Dalangtan Basin.The further study has revealed that in the sediment profile there are six reverse sequences marked by the occurrance of the late-formed minerals, such as bischofite, sylvite, leonite, etc. beneath halite in the same rhythmic unit. Since the reverse sequence is a typical feature of playa, the presence of the six reverse-sequences suggests that there were six playa periods in the history of the Dalangtan Salt Lake. |
| WANG Mi-er,WANG Yi-jie,LIU Cheng-lin,CHEN Yong-zhi.1993.THE FEATURES AND GENESIS OF THE DALANGTAN SALT DEPOSIT IN THE QAIDAM BASIN[J].Acta Geoscientica Sinica,14(1):97-114. |
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