| Taking Hongqigou-Shenshuitan gold deposit in Wulonggou area of QinghaiProvince as the study subject, and through the study of geological background in thestudy area, analysed the characteristic of altered fracture zones, the ore type and grade,genesis of the deposit and the prospecting indicators,as well as the reserves estimation,The main results achieved and understanding are as follows:1. Number IX ore crushing zone is a long and narrow stripped and located in thenorth east of orefield, it is native to the contact zones between the rock mass whichcontain dark inclusion in gneissic tonalite of Shihuigou super unit in Later Proterozoicera and the Baishahe Fm as well as meta-volcanics Fm.Number XI ore crushing zone is located in the south，as the main fracture planeof main fractures or brittle ductile shear zone. it is native to the contact zones betweenthe rock mass of monzonitic granite、 plagiogranite、 ultrabasic rock and theQiujidonggou Fm、meta-volcanics Fm of Qingbaikou systerm. In the meanwhile, thenorwest part of crushing zone inserts into the Xiaomiao Fm at east Shuizha Ditch, thesoutheast part inserts into the Qiujidonggou Fm.The two crushing zones are widespread mineralization with gold, and these twobelt are the main gold occurrence position.2. Ore minerals are very complex in their compositions，and precious metalmineral is electrum, the general metal minerals are pyrite, arsenopyrite,chalcopyrite,galena, sphalerite, pyrrhotite, etc.Ore minerals′combination is very complex, but but not in high levels, andcontains a little sulfide.Ore structure is mainly panautomorphic granular texture, hypautomorphic-panautomorphic granular texture, lepidoblastic texture, replacement texture, pressuretexture, poikilitic texture, etc.Ore structure is mainly disseminated structure, then veinlet structure andbrecciated structure.Gold occurrence state, inclusive gold accounted for91.32%, arsenopyrite whichenclave gold is double deck, namely matrix inclusive the fine arsenopyrite aggregatein the cracked breccia, while the fine arsenopyrite inclusive native gold. 3. The gold mineralization have the following geological characteristics: thebasic position of main ore-bearing fault structure is at the contact zone which betweenthe Baishahe Fm of Jinshuikou Gr, Qingbaikou system, and Wulonggou super unit,Shihuigou super unit in north-south sides, has the macroscopic positioning effect forlater mineralizing. And the four fracture structures are not only the most importantore-controlling factors, but also provide pass way and space for goldore-mineralization, while the magmation supplied thermal energy and metallogenicmaterial, and the structure in the later period played a positive role in rich andposition.4. S isotope composition of Ore-forming fluid has the value of δ34S from1.33‰to5.85‰, it shows that the fluid come from magma. The homogeneous temperaturesof mineral inclusions are between250℃and330℃, the average temperature is287℃;bursting temperature of215℃～315℃, it shows that the gold mineralization occurredin low temperature conditions; the research of mineral inclusions shows that goldmineralization was formed in epithermal conditions of weak acid and weak reductionenvironment; the main metallogenic epoch of gold is Indosinian.5. In the initial minery Shenshuitan goldfield,12ore bodies were determined inHuanglonggou section,13ore bodies were determined in Heishigou section, while28ore bodies were determined in Hongqigou section, and16ore bodies were determinedin Shenshuitan section by the research work. We estimate the total resources of thegold at5644.61kg, amont it2135.12kg at Huanglonggou,1596.65at Heishigou,1912.84kg at Hongqigou. Added the resource of east Shuizhagou at1108.48kg, thecumulative resource reached to6753.08kg in the study area. |
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