皖南粒七湾钨钼矿成矿地质特征及找矿远景

Ore-forming geological features and exploration prospect of the Liqiwan Wo-Mo ore deposit,south Anhui

通过水系沉积物地化扫面在安徽省祁门县粒七湾圈出了W、Mo、Cu、Bi、Ag等多元素组合异常,检查发现该异常区出露有花岗斑岩体,经探槽揭露取样分析发现有钨钼矿化。在2009年通过进一步工作,取得了找矿突破。粒七湾钨钼矿为典型斑岩型钨钼矿化,矿化见于岩体内部,呈细脉浸染状产出,矿化的强弱主要受岩体内部裂隙发育程度制约,矿体呈似层状、透镜状,产状较平缓;主要矿体间断地赋存于标高-146.5～80.0m间,共圈出矿体26个,初步估算钨、钼资源量(333+334)均可达中型规模。矿区的土壤中有以W、Mo、Cu、Bi、Pb、Zn元素为组合的地化异常响应,各异常元素分带现象明显,W、Mo、Cu、Bi为异常内带元素,Pb、Zn矿则为异常外带元素,W、Mo的异常侬集中心指示了矿化富集区。矿区东北部分布有一个磁异常,反映存在隐伏小岩体,根据区域磁异常分析,该岩体可能与粒七湾岩体同源。

Geophysical Survey Team of East China Metallurgical Bureau of Geology and Exploration found multi-element association anomalies of W, Mo. Cu, Bi and Ag in Liqiwan, Qimen County, Anhui Province through scanning geochemical survey of water system sediments in 1980s, and then checked the anomalous area leading to discovery of the outcrops of granite porphyry intrusion, and assay of trench samples indicated W-Mo mineralization. Follow-up work in 2009 brought a breakthrough in exploration. The Liqiwan W-Mo ore deposit is typical of porphyry W-Mo mineralization, which occurs inside the intrusion as veinlets or disseminations, and whose intensity is mainly confined by fissure development inside the intrusion. Ore bodies are stratoid and lenticular in gentle occurrences. Major ore bodies are disruptly hosted between elevations of -146.5 to 80.0m. A total of 26 ore bodies have been found. Preliminary estimate indicates that W and Mo resources （333＋334） are all medium in size. There are geochemical anomalies of multi-element association of W, Mo, Cu, Bi, Pb and Zn in soils in the ore field, and the zoning of anomalous elements is evident, with W, Mo, Cu and Bi being in the inner zone and Pd and Zn in the outer zone, and the anomalous concentration center of W and Mo indicating mineralization enrichment area. There is a magnetic anomaly occurring in northeast of the ore field, a reflection of a small hidden intrusion, which, based on regional magnetic anomaly analysis, is possibly re- suited from the same source as Liqiwan intrusion and has good prospect of exploration.