华南隐伏-半隐伏脉钨矿床的地表标志带

一、脉钨矿床的形态分带和标志带概念华南地区的脉钨矿床,多与花岗岩有成因上的联系。按工业矿脉与成矿岩体的空间关系,可将脉钨矿床分成三类,即外接触带矿床、内接触带矿床和内外接触带矿床。这三类矿床都具有形态分带性。外接触带和内外接触带矿床的形态分带特征基本相同,发育良好、保存完全者在垂直方向上综观可作五形变分带,即自上而下为线脉带、细脉带、薄脉带、大脉带、消失带。下部大、薄脉是上部线、细脉合并变大而成的。内接触带矿床只能分出三个

The Surface Indicator Zones Of The Blind-Semi-Blind Tungsten Vein Deposits In South China

Tungsten vein deposits in south China are characterized by zonation in appearance. Vertically five zones could be roughly recognized in downward succession: linear vein zone, veinlet zone, thin vein zone, large vein zone and extinction zone. The so-called surface indicator zones refer to the first two zones occuring at the top of a deposit which, having no commercial value themselves, serve well as an indicator for mineral exploration. As weathering and rock disintegration vary in extent from deposit to deposit, these deposits are terminologically called blind to semi-blind deposits. The following aspects are emphasized in the identification and evaluation of the indicator zones: (1) their structural positions; (2) their fabric patterns in plane; (3) their horizontal zoning; (4) their characteristics in shape, such as the structural type, attitude, configuration, size, density of veins and total thickness; (5) the indicating components present, including diagnostic minerals (nonmetallic and/or metallic minerals) and indicator elements (metallogenic elements, volatile elements and rare or alkaline elements); (6) wall rock alterations and, zonation; (7) geologic and geochemical halos surrounding these indicator zones, chiefly vein halo, heavy mineral halo, primary dispersion halo, secondary dispersion halo and evaporite and thermal halos of mineral inclusions. It should be pointed out that similar indicator zones have been found in numerous other endogenic metallic deposits. These zones can perform the same function of indicating mineralization in spite of their respective peculiarities. Therefore, great attention should be paid to the observation and evaluation of mineralized linear vein zones or veinlet zones in search for endogenic metallic deposits.