In remote sensing image interpretation, different grades of linear structure, different types of circular structure, different combinations of linear and circular structure, and color anomaly are the most useful ioformetion for porphyry copper.1. The Scale of Porphyry Copper Connect Directly with Different Grades of Linear Structure Regional porphyry copper zones are controlled directly by large regional linear structure zones and their convergent patters. The regional linear structure zones which show light color zones in image usually are regional compression crustal or over-crustal faults, over 100km in length,called peripheral-major linear structure zones. In addition, a lot of secondary linear structures which intersect with the peripheral-major structures in suitable angle, form joining-up structures, of ten also show light color in image, directly control ore field distribution and deposit location. They are called crosswise linear structure, generally from 1 to 100km in length, mainly include 3 types and show tension characteristics. In fact, more lower grade of linear structures (faultsand fractures) which usually form circle, radiate like fault and fracture system, directly control alteration and mineralization related to the perphyry copper.2. Different Assemblages of Multilayer Circular Image Feature Reflect on Different Circular Structure Blocks Contained Porphyry Copper Almost all porphyry coppers relate to circular blocks, especially to Ⅲ or Ⅳ grade circular structure blocks (D. From 50 to 500km), including upwarped circular blocks, downwarped circular blocks and foldcircular blocks, fault circular blocks etc.. They control the location of porphyry copper. In igneous circular blocks, coppers usually lie in: (1) On the demarcation surface or the center of multilayer circles reflected on batholith and small hidden rock body; (2) Inside or on the edge of multilayer circles reflected on crater and crypto-explosive breccia pipe; (3) In alteration zone, the circular features show the volcanic rock, intrusive rock body, volcanic apparatus and alteration envelope.3. Linear-Circular Structures Jointly Control the Distribution of Deposit or Field of Porphyry Copper The position of linear structure intersecting or contacting with circular block structtire generally indicates the canal of ore fluid and the space of ore capacity, as a result, it control the distribution of deposit or field of porphyry copper. They mainly include: (1) The action that multilayer inter-contacting circles intersect with linear structure; (2) The out -circle section of multilayer concentric circles, haled in the angle area intersected by two groupo of linear structures;(3) The demarcation surface or the center of multi- layer near concentric circlar block, located in the area intersected by two groups of linear structures; (4) In the big circle with small intercontacling circles, two groups of linear structures intersect, a series of more small circles separately appear along the two groups of linear structures in string or belt, the deposit appears in the edges of the more small circles; (5) Two groups of linear structures intersect in double concentic circles, pluy porrphyry copper appears in the edge of small inter circle.4. The boor Anomaly of Circle and Circular Belt Present Alteration Related tO the Mineralization of Porphyry Copper TM and MSS images processed by computer can clearly show the abnormal color circular belt caused by alteration related to porphyry copper. For example, in TM [6/7 (red), 6/5 (green),6/4 (blue)] image of Wunugetushan quartz-sericitization allerations in which deposit is formed present which circular belt, and illite hydromica alterations in light cyan is outer-circular belt,aroud the which one.
周正武, 张建枢, 王卫东. 大型斑岩铜矿的遥感信息探讨[J]. 国土资源遥感, 1996, 8(2): 10-20.
Zhou Zhenwu, Zhang Jianshu, Wang Weidong . THE PROBING OF REMOTE SENSING INFORMATION IN LARGE SCALE PORPHYRY COPPER. REMOTE SENSING FOR LAND & RESOURCES, 1996, 8(2): 10-20.