淮安盐盆东南部中生界白垩系石盐矿物中Br^-离子化学特征及其指示意义

Characteristics of Br^- in halite mineral of Mesozoic Cretaceous in southeast Huai'an salt basin and its significance

目前对淮安盐盆中生界白垩系石盐沉积物质来源是陆相成因还是海相成因尚存在争议。通过对淮安盐盆东南部石盐矿物中Br^-离子含量及溴氯系数进行研究,结果表明:区内石盐矿物中Br^-离子含量介于3×10^(-6)~42×10^(-6),说明淮安盐盆东南部石盐矿在不同阶段矿物结晶时,卤水中Br^-离子浓度普遍较低,结合区内孢粉组合、化石组合特征,认为具有陆相成因特征;其溴氯系数介于0.008~0.139,其中低于海相成因最初沉积阶段溴氯系数0.11的占90.7%,说明淮安盐盆盐类物质来源主要来自陆相成因的地表岩石风化淋滤或地下深层卤水。

At present,Mesozoic Cretaceous′Halite sedimentary source in the southeast of Huai＇an basin still has a dispute about continental origin or marine origin.This paper studied Br-content characteristics and Br^- Cl-′coefficient in the halite of Huai＇an salt basin.The result showed that the Br-concentration ranged from 3×10^-6 to 42×10^-6,which indicates that the Br-ion concentration was generally lower in different stages of halitemineral crystallization.Combined with palynological assemblage and fossil assemblage characteristics in Huai＇an salt basin,we concluded that the Halite ore deposit had the features of continental origin.Br-Cl-coefficient ranged from 0.008 to 0.139,and 90.7% of the statistical data were below Br^-Cl-′coefficient 0.11 of the initial stage of deposition of marine origin.All these figures illustrated the source of salt in Huai＇an basin came from the rock of the earth＇s surface weathering and leaching or deep underground brine.