Discovery of Borax-bearing Mirabilite Beds in Dong Co, Northern Tibet, and Its Palaeoclimatic Significance  

作　　者：魏乐军 郑绵平 刘喜方 蔡克勤 乜贞 

机构地区：[1]Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037,China University ofGeosciences, Beijing 100083 [2]Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037,Open Laboratory of Saline Lake Resources & Environment, Chinese Academy of Geological Sciences, Beijing 100037 [3]China University ofGeosciences, Beijing 100083

出　　处：《Acta Geologica Sinica(English Edition)》2002年第3期271-282,共12页地质学报（英文版）

基　　金：National Natural Science Foundation grant 49833010.

摘　　要：The authors investigated lacustrine chemical sediments on terrace-I of DongCo-a salt lake in the interior of the northern Tibetan Plateau and firstly discovered borax and acomplete sedimentary section with five pure mirabilite beds. According to the sedimentarycharacteristics of rhythmic layering, palaeotemperatures for the formation of the cold-phasemineral-mirabilite-at the profiles and ^(14)C dating, the authors applied the theory and method ofcomparative salinology in the study of the history of the palaeoclimate and palaeoenvironment ofDong Co in the early and middle Holocene and drew the conclusion that the salt lake had experiencedthe following climatic evolution: the warm and moist stage (>8470 a HP and possibly to 10500 aHP)->cold and dry stage (8470-8170 a BP)->warm and moist stage (8170-7590 a BP)->stage of repeatedclimatic oscillations (7590-7400 a BP, alternation of three dry oscillations and three moistoscillations in a generally cold climatic background)->cold and dry stage (7400-6940 a BP)->warm andmoist stage (6940-6620 a BP)->cold and dry stage (6620-6410 a BP)->warm and moist stage (after 6410a HP).The authors investigated lacustrine chemical sediments on terrace-I of DongCo-a salt lake in the interior of the northern Tibetan Plateau and firstly discovered borax and acomplete sedimentary section with five pure mirabilite beds. According to the sedimentarycharacteristics of rhythmic layering, palaeotemperatures for the formation of the cold-phasemineral-mirabilite-at the profiles and ^(14)C dating, the authors applied the theory and method ofcomparative salinology in the study of the history of the palaeoclimate and palaeoenvironment ofDong Co in the early and middle Holocene and drew the conclusion that the salt lake had experiencedthe following climatic evolution: the warm and moist stage (>8470 a HP and possibly to 10500 aHP)->cold and dry stage (8470-8170 a BP)->warm and moist stage (8170-7590 a BP)->stage of repeatedclimatic oscillations (7590-7400 a BP, alternation of three dry oscillations and three moistoscillations in a generally cold climatic background)->cold and dry stage (7400-6940 a BP)->warm andmoist stage (6940-6620 a BP)->cold and dry stage (6620-6410 a BP)->warm and moist stage (after 6410a HP).

关 键 词：Dong Co borax-mirabilite layer HOLOCENE climatic change 

分 类 号：P5[天文地球—地质学]