湖南崇阳坪地区石英脉型钨矿床的地质特征、成矿规律及成矿模式

崇阳坪地区位于南岭西段,区内出露有中华山、崇阳坪、瓦屋塘3个岩体,且在岩体内已发现了初具规模的寨溪山、上茶山、牛角界、沙溪等钨矿床,主要矿化形式为浸染状、细脉状白钨矿、黑钨矿化,常见围岩蚀变有云英岩化、钾长石化、钠长石化、电气石化、绿泥石化等,属于石英脉型钨矿床(主要为白钨矿)。区内崇阳坪岩体LAICP-MS锆石U_Pb年龄为(214.2±1.7)Ma,瓦屋塘岩体年龄为(223.1±2.1)Ma,形成于印支期,研究区内的钨矿(化)体均产于印支期花岗岩体接触带上,空间上与二长花岗岩侵入体关系密切,成矿与成岩基本同时,这填补了华南地区印支期花岗岩不能形成独立钨矿的空白。文章在总结归纳前人研究成果的基础上,结合近年来在该区找矿取得的进展,主要从以上矿床的地质特征入手,总结分析该区钨矿床的成矿规律,并在此基础上初步建立该区石英脉型钨矿床成矿模型。

Geological characteristics, metallogenetic regularity and model of quartz vein type tungsten deposits in Chongyangping, Hunan Province

Chongyangping area is located near the western part of Nanling. The area possesses such fairly large tungsten deposits as Zhaixishan, Shangchashan, Niujiaojie and Shaxi, which are distributed in the contact zone between Sinian, Cambrian, Ordovician strata and the medium-fine grained biotite granites, belonging to quartz vein type tungsten deposit. Based on performance of LA-ICP-MS zircon U-Pb dating, the authors obtained (214.2±1.7) Ma, (223.1±2.1) Ma for the Chongyangping and Wawutang rocks respectively, suggesting that they formed in Indosinian. Tungsten ore was produced in the granite contact zone, spatially closely related to adamellite granite. Mineralization occurred substantially simultaneously with the rock-forming process, and this discovery fills the gap which holds that Indosinian granite can not form independent tungsten deposit. The main mineralization forms include dissemination, veinlet tungsten and wolframite. The rock alteration types are mainly greisenization, K-feldspathization, albitization, silicification, and chloritization. According to the previous research achievements of coal liquefaction residues and the progress in prospecting work in this area in recent years, the authors reviewed the geological characteristics of these deposits, analyzed mineralization enrichment regularity, compared these deposits with the typical vein tungsten deposits in Nanling region and, on such a basis, built up a metallogenic model.