Research On Rocks & Minerals' Characteristics And Metallogeny Of Shazigou Polymetallic Deposit

A multi-metal deposit has been found in Shazigou, north Taipusiqi of the Inner Mongolia Autonomous Region in 2006, which is a significant breakthrough in the Zhengxiangbaiqi-Duolun multi-metal prospect for Au, Ag, Zn, W, Mo. The lead resource of Shazigou deposit are Mo & W.The deposit is partitioned into two parts by Donggou of Wangjiayingzi, which are, east part for W or W-Mo and west part for Mo. Wolframite was mainly found in big quartz veins on terrene, Contrarily, molybdenite in slim veins underground.Main rocks emergenced in this region are regional metamorphic rocks of Baiyun'ebo qun include mica-schist, issite, marble, granulite, etc.; contact metamorphic rocks include diopsidite, aposandstone and skarn; a kind of dynamo-metamorphic rock known as mylonite.Granites'intrusion mainly occurred in late Hercynian and early Yenshan stage, all of them are lime-alkali rocks, which are high in SiO₂ (with a average of 73.04%) and alkalinity, that is, (K₂O+ Na₂O)=2.45-8.65 & K₂O>Na₂O, low in CaO, MgO and have a supersaturation of Al. All in all, they are high in acidity and had undergone a thorough differentiation, which are propitious to deposits of W, Mo.Most of the regional metamorphic rocks near and in the deposit, especially mica-schists, have been changed in a migmatization course which are likely to be caused by granite intrusive mass. The migmatites, most of which been observed are stripped migmatite and ophthalmite, are considered as the most important adjoining rock of the ore bodies. At the same time when migmatization occurred, a huge number of pegmatite veins formed and been transported to terrene as we can see today. The veins, which could be considered as a part of migmatites, called leucosome, are known as a result of partial fusion of the regional metamorphic rocks.For ascertaining rocks' metamorphic grade of this deposit, this paper focuses on the characteristics of chief mineral constituents and metamorphic P-T condition of issite and amphibolites. Metamorphic grade has been restricted by Ti-Al^IV & (Na₂O+K₂O) -TiO₂ relationship diagrams of amphiboles and metamorphic P-T condition has been calculated by using the amphibole-plagioclase couple. Amphiboles in amphibolites are showing high Al₂O₃ and high K₂O in composition, while the FeO+MgO content are rather constant, FeO & MgO are showing negative relationship. All amphiboles belong to calcic- amphibole series according to Leak's classification and 5 mineral species could be subdivided. Plagioclases from amphibolites are all andesine. The metamorphic type corresponds to medium-high temperature regional metamorphism, while the metamorphic grade is high amphibolite facies.In author's opinion, Shazigou ore deposit can be classified as a epithermal deposit, migmatization made the regional metamorphic rocks a rigid body, tectonic movement like faults and folds destroyed the rocks and made innumerable cracks, a granite intrusive mass brought heat and boiled waters nearby to form hytrothermal deposit.