| Duo-buza mining area with an average elevation of4700m is located in GaizeCounty, Ali Prefecture, Tibet Autonomous Region, and is called the "Roof of theWorld". Due to little population,poor economic,cold weather and limited oxygen,thelevel of geological work in this immense area was limited. When a rich porphyrycopper and polymetallic deposit was found in Duo-buza mining area inBangonghu-Nujiang metallogenic belt, it got a lot of attentions from many geologicalorganizations and scholars.Duo-buza mining area is a polymetallic porphyry copper deposit which is locatedin the western part of the north side of Bangonghu-Nujiang metallogenic belt. Themetallogenic belt has a complex and diverse geological structure which is good formineralization. Bangongcuo-Kangtuo-Zigetangcuo fault is in the north ofBangongcuo-Nujiang suture zone, and Ritu-Gaize-Dingqing fault is in the south.Bangongcuo-Nujiang suture zone is irregular narrow strip, up to2000km long fromeast to west and30~90km wide from north to south. Between these two regionalfractures, a multi-scale EW compresso ductile shear、 brittle strike-slip fracture、SNextensional fault and latitudinally trending fold are developed。With the intruding ofYanshanian basic rocks and intermediate acidity rocks，Bangongcuo-Nujiang gold andcopper polymetallic mineralization belt were made up，and other metalliferous depositsuch as gold, copper, chrome，were found to be a bed zone distribution.So far, researches on Duo-buza mining area have been carried out about for10years. After many years’ investigation, a lot of direct geological data and geophysicaldata are collected and analyzed. But, the researches about the Duo-buza copper belt’smodel for exploration are far from enough. Thus, this article selects the Duo-buza copper deposits as the typical ore deposit to pick up the regional deposit identificationsymbol by analyzing the regional geophysical characteristic and the regionalgeological characteristic that include regional tectonics、regional tectonics、regionalmagmatic rock、regional symphrattism and so on. And then extract geological andgeophysical characteristics of the mining and mineral deposits in a better scale,summarize the favorable mineral-formation conditions and criteria for ore prospectingwith the geological information reflected by geological anomalies and geophysicalanomalies, and finally establish a typical multi-scale geological-geophysicalprospecting model of porphyry copper in Duo-buza.During the research of the model for exploration, we have obtained the followingnew results and understandings:(1) Based on the analysis of geological and geophysical data, we summarized thegeological anomalies and the corresponding geophysical characteristics which mineralore shows in different spatial scales.And all these anomalous characteristics whichwe have found can provide the basis for distinction between anomalies related tomineralization and anomalies not related to mineralization.(2) Based on the existing information, we tried to establish the Duo-buza modelof exploration. This model should consist of description of the main characteristics ofgeological, geophysical of ore body, the definition of core elements and prospectingmarks under the guidance of the small to large scale which contributes to the successto find mineral ore. The core elements of Duo-buza model of exploration include thestructure associative localization which was invaded by intermediate acidityrock,weak magnetic normal anomaly which is expressed as low resistivity and highpolarizability,Positive and negative company,Ultrastructure examined ofdeposits,Wallrock alteration is strong and characterized by zoning as potassic,silicification and chloritization etc,Chalcopyrite, such as the emergence of malachitesulfide. |
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