红泉膨润土成因之我见

A DISCUSSION ON THE GENESIS OF THE HONGQUAN Mg-BENTONITE DEPOSIT

前言红泉膨润土矿床具有两个显著的特点:(1) 既有钠基膨润土、钙基膨润土,还有一定数量的镁基膨润土;(2)在一般情况下,钙基膨润土在上,钠基膨润土在下,然而红泉膨润土则具有相反的空间分布,即所谓“逆向”分布的现象。红泉膨润土矿中镁基膨润土的发现和研究,不但丰富了膨润土成矿规律的认识,同时还为镁基膨润土的物化工艺性能及应用的研究提供了条件。

The Hongquan bentonite deposit, occurring in Permian 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 Mgbentonite in addition to Ca- and Na-bentonite, (2) inverse zoning with Cabentonite underlying Na-bentonite.The water table is an interface separating Ca-bentonite from Mg- and Nabentonite 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 Mg^(2+) and the relative concentration of Ca^(2+) 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.