罗布泊盐湖区固体钾盐沉积特征、分布及成因探讨OA北大核心CSTPCD

The sedimentary characteristics,spatial-temporal distribution and genetic formation of various solid potash deposits,mainly including polyhalite,carnallite and kainite in Lop Nur were summarized in this study.Polyhalite sediments mainly formed in subsidence area of Luobei Sag and are characterized by replacement origin.They rep-resent products of water-salt interaction of the potassium-and magnesium-rich residual brine with the existed cal-cium sulfate like gypsum and glauberite in sulfate-type lake.Sediments of carnallite mainly occur on the surface or near surface of fault zones in Lop Nur that fed by the deep CaCl-type brine through faults.The kainite sedi-ments mainly distributed in Nanxiaotuan area and sourced from recharges of evaporated brine in Luobei Sag due to basement inversion.The formation of solid potassium sediments in Lop Nur rely on the coupling of tectonics,provenances and arid climate in a special time window.Under the arid climate condition,the tectonic activities lead geomorphic divides to form more closed sub-sage that provides accommodations for potash deposits.On the other hand,it reactivated fault to offer essential channels for upward migration of deep fluids that modified chemi-cal composition of lake brine to finally form various potash sediments.