A synthesis of the geochemistry of silcretes and their host sediments in the Kalahari Desert and Cape coastal zone, using isocon comparisons, shows that silcretes in the two regions are very different. Kalahari Desert silcretes outcrop along drainage‐lines and within pans, and formed by groundwater silicification of near‐surface Kalahari Group sands. Silicification was approximately isovolumetric. Few elements were lost; silicon (Si) and potassium (K) were gained as microquartz precipitated in the sediment porosity and glauconite formed in the sub‐oxic groundwater conditions. The low titanium (Ti) content reflects the composition of the host sands. Additional elements in the Kalahari Desert silcretes were supplied in river water and derived from weathering of silicates in basement rocks. Evaporation under an arid climate produced high‐pH groundwater that mobilized and precipitated Si; this process is still occurring.

中文翻译：

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重新评估南部非洲硅质岩地球化学：对硅质岩起源和硅质人工制品来源的影响

使用等值线比较，对卡拉哈里沙漠和开普沿海地区的硅藻土及其宿主沉积物的地球化学综合显示，这两个地区的硅藻土有很大不同。喀拉哈里沙漠的silcretes沿排水线和盆内露头，是由近地表卡拉哈里群砂的地下水硅化作用形成的。硅化近似等容。丢失了很少的元素；硅（Si）和钾（K）是通过在低氧地下水条件下在沉积物孔隙中生成的微石英和青石而获得的。低钛（Ti）含量反映了主体砂的成分。喀拉哈里沙漠中的硅土中的其他元素是从河水中供应的，这些元素来自基底岩石中硅酸盐的风化作用。在干旱气候下蒸发会产生高pH值的地下水，从而使Si迁移并沉淀。这个过程仍在发生。