鄂尔多斯盆地奥陶系压释水岩溶地球化学模拟

鄂尔多斯盆地的压释水岩溶是在中深埋藏条件下,富含有机酸的压释水渗入碳酸盐岩含水层所产生的溶蚀作用过程及岩溶化结果.从矿物的化学成分上来看,具有较低的Sr,较高的Fe、Mn含量,反映了埋藏较深、温度较高的成因环境.包裹体的大小、形态和分布特征显示矿物形成于水流交替缓慢,温度、压力及溶液浓度变化较为稳定的环境;包裹体的化学成分表明压释水岩溶作用较强的地区,溶解离子含量较低,pH值较低;包裹体同位素分析结果显示溶蚀孔、缝充填物的(D值较高,形成于氘富集的热卤水环境.通过压释水岩溶的地球化学模拟试验与系统分析得出:压释水的溶蚀动力源于有机酸的介入;压释水的溶蚀过程是一个缓慢的渗流扩散过程;压释水的溶蚀强度与有机酸的含量密切相关.

Geochemical Model of Compaction Released Water Karst in the Ordovician of Ordos Basin

The compaction released water karsts are formed under the middle-deep buried surroundings are a process of the dissolution role between compaction released water contained organic acid and carbonate rock, are final production of karstification roles. Much content of Fe, Mn and less Sr,which reflect the surroundings of deep buried and high temperature. The size, shape and distribution of inclusion show that the mineral formed under the condition with slow current flow, and temperature-pressure-density change steadily. The chemical component of inclusion indicate that less ion content and pH value in the intension karst areas. The result of isotope in the inclusion show the (D value is high, so the filled matter formed under the hot-bittern surroundings. Through geochemical simulate experiment of the compaction released water, we come to the conclusion that the dissolution dynamics of the compaction released water is the organic acid, and the dissolution course of the compaction released water is a slowly seepage-diffused course, the dissolution intension of the compaction released water are closely correlated with the content of organic acid.