粤西推覆构造系统对金银及多金属矿床的控制

粤西推覆构造系统主要形成于海西-印支期,构造型式属褶皱式逆冲推覆构造,扩展方式为前展式,外来系统为前震旦系、震旦系和塞武系,原地系统为泥盆系、石炭系,次级逆冲断裂带多为上陡下缓的犁状形态。在横剖面上推覆构造系统中的构造带组合较齐全,且不同的构造带、构造部位成矿和控矿的作用不同,可分为:①断坪滑覆带中的矿床——新榕锰矿及银铅矿化;②推覆隆起韧性剪切带中的矿床——河台金矿;③断坡突起韧性剪切带中的矿床——大沟谷金矿;④推覆褶皱-冲断带中的矿床——大降坪硫铁矿;⑤盆内褶断带中的矿床——石径金矿;⑥前缘剥离拉伸带中的矿床——长坑金银矿;这些不同类型的矿床所具有的相关性和一致性,表明除地层岩性外推覆构造系统对该区金银及多金属矿的成矿和控矿作用。 

GENERAL FEATURES OF THE WESTERN GUANGDONG NAPPE TECTONIC SYSTEM AND ITS CONTROL ON THE NOBLE METAL AND POLYMETALLIC DEPOSITS

The western Guangdong nappe tectonic system was formed in the Hercynian and Indosinian epech. Its tectonic styles belong to the folding and thrusting nappe structure, the extended way is piggyback propagaton. The allochthon consists of the Presinian, Sinian and Cambrian Systems. The autochthon comprises the Devonian and Carboniferous Systems. The most of the subsidiary thrusting fracture shows the plough-shaped with the upper steep and the lower flat form. The structure assemblage of the nappe tectonic system is perfect in the cross section, and the structure belts andthe tectonic units show the mineralization and controling ore deposits, which can be divided into the five types according to the occurrence condition:①the ore in the flat of gliding nappe belts-the Xinrong manganese ore, silver and gold mineralization;②the ore in the ductile shear zones of the basement detachment nappe doming-the Hetai gold deposit;③the ore in the ductile shear zones of the ramp rise-the Dagougu gold deposit;④the ore in the nappe folding and thrusiting belts-Dajiangping pyrite deposit; ⑤the ore in the folding and thrusiting belts in the basin-Shijing gold deposit; ⑥the ore in the front stripping extension fault belts-Changkeng gold and silver deposit. The correlation and harmony of the different typical deposits suggest the mineralization and controling ore deposits are governed mainly by the nappe tectonic system besides the strata and lithology.