Methodology Study on the
Remote Sensing Geological Prospection is Shhanxi Province, China
Bai Xing Feng,Ran Xing
Min Shaanxi Remote Sensing Center Introduction In Remote Sensing geological prospection, the advantages of Remote Sensing technology must be made full use, according to the project, roper scales of images must be taken as the basic information and processed with computer and other means. Comprehensive interpretation can be carried out geologically to extract all necessary geological information. The author raised two or methods for the Remote Sensing geological prospection according toe h reality of Shaanxi: a. Prospection with direct marked information; b. Prospecting with indirectly marked information combined with comprehensive analysis. examples are given for these two methods. Theoretic Bases for Remote Sensing geological prospection Remote Sensing image are comprehensive miniature of objects and all of the scenes on the ground according to certain scales and also are the reality records of reflecting and radiation spectrum of surface objects on the crust. Various objects on the ground absorb, reflect (inc. disperse), transmit and radiate differently the electro-magnetic waves with different lengths. The differences of the spectrum choicely reflected and radiated by different ground objects (inc. rocks and minerals) form the physical basis for judgment of different objects with Remote Sensing images. In our work, spectrum analysis was carried out for the different rocks and minerals and the results show that the curves of reflecting spectrums are quite different. These differences forms different tones and colours of different rocks and minerals and the rocks and minerals show different imagery textures. These textures are indicator marks for geointerpretation of Remote Sensing images and the identification of rocks, and are also the theoretical basis for the Remote Sensing prospection. Methodology of Remote Sensing geological prospection. Remote Sensing geological prospection is to make use different Method. This method is an effective way for prospection of blind ore bodies or deposits, on the basis of imagery features of Remote Sensing images with data of geology, geophysics and geochemistry, integrating with the comprehensive process and analysis of al the data. necessary statistics should be carried out mark predictions.
Prospecting Example ion This Study I. Tectonic alteration zones wer176e found out in Shanyang Country when interpretation was carried out on images of Shangzhour region. They were confirmed by the field testification to be 30m in width and 150m long. I these zones, strong silification, carbonation and puritization were seen. Pyrite occurs in block, veilwnt and spot and in zones along the contacted area of carbonation with silicification, pyrite grains are small smaller from South to the North. Analysis results of the samples show that Cu is upto 1000ppm, Pb 100ppm and Au. 0.38g/t. II. Four anomalies were found in Qinggangping Bayyan areas, and they were confirmed to be quarts veins with gold and lead mineralization in different length and the thickness is 0.5 – 2m Godl is up to 1.72g/t according to the sample analysis. III. An anomaly area was ground near the Wufeng Village and it was verified to be radiating uranium layer inorganic, asphaltic sand stones. IV. An anomaly area was found near the Wufeng village and it was verified radiating uranium layer in organic, asphaltic sand stones imagery features shown by different rocks and minerals on the images, through transmission of imagery information according to image elements and geological elements, with extraction of mineralization information in the light of geological features and through detailed analysis, inference and judgement to make prospection and find minerals deposits. Remote Sensing geological prospection methods followed in our work can be summed up for the minerals, and with theses marks and by means of analogy, new deposits or targets cane b predicted and found directly. This method can be divided into two ways. 1) Prospection with mineral outcrops mineral outcrops are a kind of direct prospecting marks. Outcrops of different minerals often bear special colours and physical properties. On image, these colors and physical properties show differences of tones and texture in contrast to the background. These differences are the direct interpretation marks of different minerals. 2) Prospection with marks of layer and petrology control Deposits are always in close relation with rocks and structures of certain age in time and space and it is especially obvious of that endogenetic deposits are in close relation with petrology. For instance, in Shaanxi, placer gold often occurs in the river bed and terrace of the first stage in Cenozoic era; deposits of chromium, cobalt, nickel, and many nonferrous metals such as gold copper, mercury and antimony are closely related to rifting tectonics. As for minerogenetic properties of granite rock bodies, they are different with different ages and petrology. Skarn deposits occur in the contact metamorphic zone of granite with carbonate rocks. Exogenetic deposits are often related to sedimentation formations of certain age. Thus the target areas can be circumscribed for prospection if the small rock bodies are interpreted out from Remote Sensing images. And in Qing-Ba region, ductile or fragile-ductile zones to be interpreted out are the directions of prosperiting. The first step of this method is to interpret out the layers, rock bodies and veins bearing ores, and them further analysis are carried out on the imagery features of these ore-bearing layers and bodies, to find out the anomaly areas so s to find out the ore deposits. in Heshang Formation. Samples show the radio-strength in up to 500Y. During the compilation of maps for the Remote Sensing mineral prediction, detailed study and analysis of geological environment for mineralization distributions and minerogenertic imagery features were carried out and tens of minerolization areas were found, among them, 15 were verified to be significant worth of further prospecting (for gold, 7 spots, uranium anomaly layers, 4 and 2 copper mineralization areas, 1 bauxite, 1 molydenum mineralization area. Conclusions From the verification results of areas of minerogenetic prediction circumscribed I images of Shaanxi, China, confirmed mineralization areas are up to 75%. This shows that it is applicable and possible to adopt the Remote Sensing method in combination with geological, geophysical and geochemical data to make prediction for minerogenetic targets. This method shows more advantages especially in the areas with higher degrees of geological work and study. In a word, it is beneficial to make applications of Remote Sensing in the prediction for minerogenetic targets. |