Origin of the late Cretaceous potash-bearing evaporites in the Vientiane Basin of Laos δ11B evidence from borates》.pdf

Journal of Asian Earth Sciences 62 (2013) 812–818 Contents lists available at SciVerse ScienceDirect Journal of Asian Earth Sciences journal homepage: www.else /locate/jseaes Origin of the late Cretaceous potash-bearing evaporites in the Vientiane Basin of Laos: d11B evidence from borates Xiying Zhang a,b,⇑, Haizhou Ma a, Yunqi Ma a, Qiliang Tang a, Xiaolong Yuan a a Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, PR China b Graduate School of the Chinese Academy of Sciences, Beijing 100039, PR China a r t i c l e i n f o a b s t r a c t Article history: The evaporites on the Khorat Plateau comprise one of the largest potash deposits in the world, and their Received 4 April 2012 origin has long been a controversial problem. Based on boron isotope measurements from borate as a Received in revised form 14 November 2012 good indicator to distinguish marine and nonmarine evaporites, the borates of potash layers were iden- Accepted 25 November 2012 tified and the results were used to indicate the source of evaporites in the study area as representative of Available online 5 December 2012 the whole Khorat Plateau. The results show that the main borates include boracite and hilgardite. The boracites occur as crystals and ooids with minor amounts of hilgardite aggregates. The range of d11B val- Keywords: