Sedimentary rock-hosted Au deposits of the Dian–Qian–Gui area, Guizhou, and Yunnan Provinces, and Guangxi District, China
Sedimentary rock-hosted Au deposits of the Dian–Qian–Gui area, Guizhou, and Yunnan Provinces, and Guangxi District, China
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DOI：
10.1016/j.oregeorev.2005.03.014
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发表时间：
2007-04
影响因子：
3.3
通讯作者：
S. Peters;Jiazhan Huang;Zhiping Li;Chenggui Jing
中科院分区：
文献类型：
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作者：
S. Peters;Jiazhan Huang;Zhiping Li;Chenggui Jing
滇黔桂地区沉积岩型Au矿床产于扬子（华南）前寒武纪克拉通西南缘沿着古生代和早中生代沉积岩中。大多数矿床具有与卡林型Au矿床相似的特征，在区域尺度上与煤、Sb、重晶石、As、Tl和Hg矿床在空间上相关。沉积岩型Au矿床受浸染状层控和（或）构造控制。这些矿床具有许多相似的特征，特别是矿物学、地球化学、赋矿岩石和构造控制。大多数矿床与构造穹隆、层控角砾岩体、不整合面或强烈脆韧性变形带有关，如右江断裂系。典型特征包括不纯的碳酸盐岩或钙质和碳质寄主岩，其中含有浸染状黄铁矿、白铁矿和毒砂，通常含有μ m大小的Au，通常在黄铁矿的富As边缘和浸染中。晚期雄黄、雌黄、辉锑矿和汞矿物与早期形成的硫化物矿物在空间上共生。少量的贱金属硫化物，如方铅矿、闪锌矿、黄铜矿和Pb-Sb-As-硫盐也存在。岩石局部硅化并蚀变为绢云母粘土（伊利石）。岩石和（或）河流-沉积物地球化学特征通常包括As、Sb、Hg、Tl和Ba的高浓度。滇黔桂地区普遍缺乏火成岩，这意味着非深成岩型成矿作用。有些矿床含有证据表明，金属的来源可能源于沉积堆的碳质部分或其他沉积层或火山层。这一成因过程可能与该地区石油和汞的形成和活动有关，也可能与含As、Au和Tl煤层有关。许多矿床还含有结构和特征，表明受构造穹隆或剪切带的强烈构造控制，并表明同变形矿床，可能与右江断裂系统有关。滇黔桂地区的几个沉积岩型Au矿床也是红土型的，Au品位在深风化作用中富集并提高。
Sedimentary rock-hosted Au deposits in the Dian–Qian–Gui area in southwest China are hosted in Paleozoic and early Mesozoic sedimentary rocks along the southwest margin of the Yangtze (South China) Precambrian craton. Most deposits have characteristics similar to Carlin-type Au deposits and are spatially associated, on a regional scale, with deposits of coal, Sb, barite, As, Tl, and Hg. Sedimentary rock-hosted Au deposits are disseminated stratabound and(or) structurally controlled. The deposits have many similar characteristics, particularly mineralogy, geochemistry, host rock, and structural control. Most deposits are associated with structural domes, stratabound breccia bodies, unconformity surfaces or intense brittle–ductile deformation zones, such as the Youjiang fault system. Typical characteristics include impure carbonate rock or calcareous and carbonaceous host rock that contains disseminated pyrite, marcasite, and arsenopyrite—usually with μm-sized Au, commonly in As-rich rims of pyrite and in disseminations. Late realgar, orpiment, stibnite, and Hg minerals are spatially associated with earlier forming sulfide minerals. Minor base–metal sulfides, such as galena, sphalerite, chalcopyrite, and Pb–Sb–As–sulphosalts also are present. The rocks locally are silicified and altered to sericite–clay (illite). Rocks and(or) stream-sediment geochemical signatures typically include elevated concentrations of As, Sb, Hg, Tl, and Ba. A general lack of igneous rocks in the Dian–Qian–Gui area implies non-pluton-related, ore forming processes. Some deposits contain evidence that sources of the metal may have originated in carbonaceous parts of the sedimentary pile or other sedimentary or volcanic horizons. This genetic process may be associated with formation and mobilization of petroleum and Hg in the region and may also be related to As-, Au-, and Tl-bearing coal horizons. Many deposits also contain textures and features indicative of strong structural control by tectonic domes or shear zones and also suggest syndeformational ore deposition, possibly related to the Youjiang fault system. Several sedimentary rock-hosted Au deposits in the Dian–Qian–Gui area also are of the red earth-type and Au grades have been concentrated and enhanced during episodes of deep weathering.