西秦岭甘肃夏河—合作地区与中酸性侵入岩有关的金铜多金属成矿系统及找矿预测

甘肃夏河—合作地区岩浆岩与矿产分布具有分带性：夏河-合作断裂以北侵入岩规模较大，以岩基、岩株为主，发育Cu、Au、W、Mo、Pb、Zn等以中高温元素为主的矿化，受岩体边缘接触带及断裂双重控制；夏河-合作断裂以南侵入岩规模较小，多以小岩株、脉岩出现，发育Au、Hg、Sb等中低温矿化，受断裂破碎带控制。地球化学组成显示，该区侵入岩具有镁闪长岩、TTG岩套的双重特点，为"热壳"+"热幔"的壳幔结构，成矿条件极为有利。硫、氢、氧稳定同位素特征指示，成矿物质主要来自地幔岩浆析出的热液，后期有大气降水的参与。夏河—合作地区为与中酸性侵入岩有关的金铜等多金属矿成矿系统，在夏河-合作断裂以南，剥蚀较浅，可寻找远成低温热液型金、锑矿等，在其深部还应注意寻找斑岩型或矽卡岩型铜金矿床。而在剥蚀程度较高的北带，应以斑岩型和矽卡岩型矿床为主。

The Au-Cu polymetallic mineralization system related to intermediate to felsic intrusive rocks and the prospecting prediction in Xiahe-Hezuo area of Gansu,West Qinling orogenic belt

The distribution of magmatic rocks and mineral deposits in Xiahe-Hezuo area has a zoning characteristics:The intrusive rocks in northern Xiahe-Hezuo fault have larger scales and are mainly batholiths and stocks.The mineralization in intrusive rocks is dominated by medium and high temperature elements, such as Cu, Au, W, Mo, Pb and Zn, and is controlled jointly by the contact zone at the edge of rock mass and the fracture.The intrusive rocks to the south of Xiahe-Hezuo fault are smaller and are mainly small stocks and dikes.The mineralization in intrusive rocks is dominated by medium and low temperature elements and is controlled by the fracture.Geochemical characteristics in this area show that the intrusive rocks have the dual characteristics of magnesium diorite and TTG rock suite, and structurally belong to crust-mantle structure that is "thermal shell" + "thermal mantle"; therefore, the metallogenic condition in this area is extremely favorable. S, H, O and other stable isotope characteristics show that the ore-forming material was mainly derived from the hydrothermal fluid in the mantle magma and, in the later period, there occurred the participation of atmospheric precipitation.The Au-Cu polymetallic ore-forming system in Xiahe-Hezuo area was associated with medium-acid intrusive rocks.Therefore, exploration should be focused on searching for remote low temperature hydrothermal gold and antimony deposits in the shallow part and searching for porphyry and skarn deposits in the depth to the south of Xiahe-Hezuo fault, due to the shallow denudation degree.However, the prospecting should be based on porphyry and skarn deposits to the north of Xiahe-Hezuo fault characterized by a high denudation.