Brine extremely rich in potassium,boron and bromine has been discovered from the Middle Triassic Leikoupo Formation at a depth of 4300 m in Sichuan Province.It contains-50g/L of K^+,>92g/L of Na^+,>12g/L of B2O3,>2.36g/L of Br^- and -0.030g/L of I^+.The solid precipitates during evaporation at 25℃ include KB5O8·4H2O,K2B4O7·3H2O,MgCl2·6H2O and KMgCl3·6H2O.The brine ranges from 2.2‰,to2.8‰(SMOW)inδ^18O,-38‰-53‰(SMOW)in δD,15.6‰inδ^34S,and 13.5‰-15.1‰inδ^11B.These data,particularly the isotopic composition of boron,indicate that the brine has a composite derivation from marine and nonmarine brines and dissolved marine evaporites in the Triassic system.
展开▼
