Research On Preservation Condition Of Regional Deposits Based On RS And GIS

The deposit formation is a result of complex geological processes .The majority ofdeposits is subject to changes in various forms and degrees after their formation. Thesynthetic research of ore-forming genesis, post-ore change and modification is favorof the probability of deposit prediction. The research on the post-ore changes is notonly favorable for the forecasting and exploration of mineral resources,but alsobeneficial for the improvement of the ecological environments of mining area.The north of Sanjiang region is selected as the study area, with latitude N32o ～34oand longitude E94o～97o. Sanjiang region lies in the east of Tibetan plateau, which isone of the important copper multi-mineral metallogenic belts in China. There are 32copper occurrences, and 24 important copper deposits. The elevations of all depositsare more than 4600m, and the deposits are suffered with denudation and erosion.Since it is bad environment, geological work is usually limited in study area.Therefore, it is significant to use remote sensing and GIS techniques to researchdeposit, preservation. Major findings are as follows:1. Based on the regional ore-forming environments to Tibetan plateau evolvementresponse, the modes of ore-forming process (genesis), post-ore changes andmodification are built.2. Based on geological abnormity theory, the remote sensing and GIS techniquesare used to extract factors (geology, geochemistry, geography and remote sensing) ofdeposit, preservation in study area.3. With ore-forming factors and ore-deposit preservation factors, weights ofevidence are used to quantitative assess regional mineral resources. The factors inweights of evidence model must satisfy conditional independence. Therefore, themore reasonable and significant factors can be extracted, which are in favor ofquantitative assessing mineral resources in study area.4. Using analytic hierarchy process (AHP) to research regional deposit, preservation.Based on the extracted factors with weights of evidence, new variables of regionalcopper occurrences including materials, change and protection factors can be built.According to AHP method to compute the weights of new variables and the mineralresources in study area, combing regional denudation and erosion of bedrocks andorebodies, five ore-forming potential regions were plotted out.5. Quantitative prediction and assessment of typical deposit from four dimensionpoint of view. Based on the denudation and erosion speed of regional bedrocks,combing the max and min elevations and other parameters of copper orebody, thedenudation speed of copper reserves can be computed.