The Study On Metallogeny And Localizing Forecast Of Yulong Porphyry Copper-Molybdenum Mineralization, Xizang (Tibet)

It is well known that Yulong copper deposit, situated in the Tethys Tectonic-Metallogenic domain, is the largest porphyry Cu (Mo) polymetallic deposit in our country. And Yulong porphyry Cu (Mo) ore belt, east Tibet, is an important copper prospecting zone, and one of the Cu metal resource reserve regions of our country.Numerous specialists and scholars have studied the deposit through various ways and views since the end of 1970s. But we still lack of credible and general understanding on the relation between quick plateau uplift and the forming-reserving-covering of the deposit, the problem about the models and mechanisms of dynamics and thermodynamics of the mineralization porphyry forming and emplacement, the problem of mineralization series formed in deep process and exchange between the crust and the mantle, and the problem of mineralization potentiality and mechanism of the porphyry in the Himalayan period which have an effect on the resource structure and resource situation of our country. And it is difficult to define the practical problem about the complicated mineralization setting, element association and ore body series. However, with unceasingly perfecting of the theory of continental dynamics and unceasingly accumulating geophysical and geochemical formation, it is possible to study the metalization of the Yulong Cu deposit, to build up a synthetical information ore-finding model for Himalayan porphyry copper deposit with the continent collision and plateau uplift controlling ore forming, and to build up a metallogenic model of porphyry-skarn oxidized copper ore body in such unique geological and geomorphologic conditions. So from 1995, the author has taken part in some projects sponsored by former National Planning Department, National Science Department, the Ministry of Land and Resource (former Ministry of Geology and Minerals) and Tibetan Geology Bureau. Exploration work and research projects of various levels have been carried out corporately by the Sixth Geology Team of Tibetan Geology Bureau and Chengdu University of Technology. Throughsystematic study, some progresses have been acquired, which have not only enlarged the reserve of the deposit and found out the mineralization genesis, but also basically resolved the key problem about the reserve of the oxidized copper ore body which will be mined in the first stage.So, this thesis takes Yulong porphyry copper deposit and sedimentary-volcanic-tectonic evolution of Changdu basin where the deposit occurs as study subject, and centers around the specific mineralizing process of alkaline porphyry Cu deposits and regional metallogenic background of porphyry copper deposits. It builds up a location prediction model of all series ore bodies, and metallogenic model of porphyry-scarn oxidized copper ore body in such unique geological and geomorphologic conditions, and also builds up a synthetical information ore-finding model for Himalayan porphyry copper deposit with the continent collision and plateau uplift controlling ore forming by studying Yulong deposit comprehensively and systematically.So far as we know, the Yulong porphyry copper deposit, situated in the Jinshajiang-honghe porphyry Cu (Mo) ore belt in the east Himalayan tectonic-metallogenic domain, has the most thorough mineralization series, most complex mineralization elements, and most uniquemetallogenetic condition among the porphyry deposits.By region geophysics, region geochemistry tectonic-stratigraphic, paleo-geomorphologic, lithochemical, geochronological study, it has been pointed out that the Yulong copper deposit has undergone several tectonic settings transforming from continent collision, continental rifts development to inland orogeny. The crust of the area is thick with the thickness of 50 to 80 km, and the northern is thicker than the southern. There is an admixture of the crust and the mantle whose thickness is 20 km and depth from 60 to 80 km. There are some up-flowing bodies of asthenosphere whose thickness is from 100 to 200 km. The evidences o...