古沉积期钙质夹层成因及其过程分析

在古沉积地表环境中,钙的富集一般以成片、板状等形式产出,本次通过物理化学分析手段,指出Ca₂ 离子的来源,Ca₂ 离子富集条件及钙积层形成机理及其主控因素。研究结果表明,Ca₂ 离子从硅铝酸盐矿物颗粒中分离出来,与大气酸性水的存在密不可分,湖平面的持续下降,气候干旱,蒸发量大于降水量,河道频繁迁移摆动,河湖过渡处水流不畅等因素,有利于重碳酸钙分解形成碳酸钙沉淀,使钙积层成片、成板状大范围分布。

Causes and process analysis of calcareous interbeds in paleo-sedimentary period

In the paleodepositional surface environments, the enrichment of calcium is generally shown as plate-like and flaky, the thesis point out the origin of the Ca2 , the conditions of the enrichment of the Ca2 and the forming mechanism and dominated factors on the caliches through physical-chemical study. The results show that the Ca2 is dissociated from silicon aluminate particles; they are closely connected with the existence of the atmospheric acidic water. When the climate is dry, with the evaporation larger than that of precipitation, the lake surface keeps decreasing; the river diverting or the transition flow blocked, etc., which are all beneficial for the decomposition of the heavy calcium carbonate, thus depositing Calcium Carbonate, making the caliches scattered largely as plate-like and flaky.