Abstract:The Hongquan bentonite deposit, occurring in Perraian strata, is composed of twelve ore beds which generally contain 80% montmorillonite and also have kaolinite hydromica, quartz, carbonate and chlorite as impurities. The Hongquan bentonite deposit is characterized by (1) containing Mg-bentonite in addition to Ca- and Na-bentonite, (2) inverse zoning with Ca- bentonite underlying Na-bentonite. The water table is an interface separating Ca-bentonite from Mg- and Na- bentonite with the former lying below and the latter two above the water table. Mg-bentonite is distributed mainly at surface and-grades downward into (Mg, Na)- and then Na- bentonite. Mg-bentonite is formed as a result of the action of Mg-rich water on primary Na-bentonite. The permeation of Mg-rich water from the surface downward and the formation of Mg-bentonite result in the decrease of Mg2+ and the relative concentration of Ca2+ in underground water; this contributes to the formation of Ca-bentonite below the water table. The formation of the Hongquan bentonite deposit is closely related to Permian volcanic eruption in that the volcanic ash seems to be the major source of the ore-forming materials. Thus, the distribution of the Hongquan bentonite is strictly confined to Permian strata, suggesting that the deposit is of volcanic-sedimentary type
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张和纬.1986.红泉膨润土成因之我见[J].矿床地质,5(3):68~74.1986.A Discussion On The Genesis Of The Hongquan Mg-Bentonite Deposit[J].Mineral Deposits5(3):68~74
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