Lancang Old Factory Lead-zinc Imaging Line - Ring Structure Deposits Positioning Mode

The Laochang silver-lead-zinc and polymetallic ore deposit of Lancang city Yunnan province is the single large-sized lead-zinc ore deposit in the Changning-Menglian mineralization belt.It has been mined since 1404 A.D., and became the paramount important mine and metallurgical base by now.But the resources will be exhausted in no more than 10 years according to the rate of production.The mine enterprise which has been restricted by the exhausted resources will have to be closed in few years later.Experts predict that metallogentic conditions are excellent around the Laochang ore deposit according to the metallogentic regularity and geology, geophysical and geochemical data of this ore field.Although plenty experience gotten after tens of years exploitation,there are no deep researches yet, which influenced the ore prospect and research on the metallogentic regularity. Conflicts become sharpen between the leaping demand for mineral resources and the increasing difficulty of ore finding.So,it is needed that metallogenic prediction using synthetic information in this region referenced new theories of deposit and advanced technology methods both here and abroad,especially scanning the whole region in a short time using the remote sensing technology characterized by efficiency,high precision,poly-spectrum and economic, which is helpful for collating and stipulating ore-tectonics,extracting alteration information,and making a remote sensing geology exploration model of Laochang deposit,based on which predicting the metallogenic areas.The ore deposit remote sensing geology is an interdisciplinary study of gitology and remote sensing geology,which syncretizes the methods of deposit geology and remote sensing geology to identify the inherent relationship between deposit characters and remote sensing information,distinguish the linear and ring structures and their grade system from numerous and complicated lineaments and rings,extract exploration information of tectonic,intrusive body,tectonic denude station and week geology information,such as alteration, special rock and so on.According to the information,the metallogenic areas and the targets for exploration work would be predicted in a short time.Combine with "the research for solid location prediction and reserves increasing of Lancang silver-lead-zinc-polymetallic ore deposit of Yunnan province",which is an institute and university cooperated item of Yunnan province,this paper searched after the exploration scheme which extracted the deposit remote sensing geology information centrally according to the basic theory and method of deposit remote sensing geology.The author got some results hereinafter by using multi-methods together,such as remote sensing digital image manipulation, Man-computer interactive interpretation,GIS space analysis, necessary geology field survey,and so on.1.Searchering after a remote sensing exploration method that is "remote sensing geology metallogenic background- metallogenic area- alteration abnormal area- linear-ring structure for ore deposit location".First,based on an interpretation of the low resolution image,the author divided the imagine-geology units of southwest Yunnan and around region,extracted region linear-ring structure and analyzed in combination with region geophysical and geochemical data to find the remote sensing geology metallogenic background of Laochang ore deposit and the relationship between the linear-ring structures and the distribution of ore deposits,then on the basis of tone anomaly information in Lancang region predicted the metallogenic areas;second, processed digital TM imagines of the metallogenic area,based on which extracted alteration information and ore field linear-ring structures;lastly, predicted the targets for exploration work in near future based on an interpretation of deposit location linear-ring structure using the high resolution images of the alteration area.This exploration method not only suits to the metallogenic geology theory but also adequately exerts the speciality of remote sensing technology,which is fit for the mountain places where the environment is hard and geology work have been done little.2.Defining the remote sensing geology metallogenic background of Laochang ore deposit.This paper Pointed out firstly that the metallogenic background of Laochang ore deposit is the NNW Gengma-Laochang-Mengzhe lineation,which is the boundary of secondarily units in the near NS Lincang-jingdong(of Burma) undertone arc strip.The Lincang granite batholith affected the formation of Laochang deposit.The NW Heihe fault was not a ore control tectonic but occurred after the main mineralization epoch.3.Based on an interpretation of linear and ring structures and the extraction of alteration information from TM imagines,in combination with ore deposit geology and geochemical data,the authors formulated a linear-ring structure model for ore deposit location in the Laochang ore district and defined for the first time that the ring-ring transverse overlapping style structure was the ore control tectonic of Laochang deposit.The NS axial Nanlao ring and the EW axial lenses series reflect the Variscan volcanic depressions and the Yanshanian-Himalayan concealed intermediate-acid intrusive bodies respectively,and their superimposition has formed Laochang ring-ring transverse overlapping style structure;the NW-trending and NE-trending conjugate structure belts formed contemporaneous with or a bit later than the concealed intrusive bodies have overlapped and dissected ring structures,and the intersections of various structures are places favorable for mineralization.The large tone anomaly patches indicate areas of near-ore wall rock alteration.The remarkable parity of poly-geoscience linear and ring structures provided evidence for the multiple sources and epochs genesis of Laochang ore deposit.4.Attempting some digital image processing versions that suit for extracting wall rock alteration information of Laochang ore deposit.The actual methods for extracting alteration information aim to stand out the iron staining and argillation mostly,but few references research the image abnormality resulted by spectral diagnostics of the manganiferous altered mineral.Whereas,in Laochang ore deposit there are not only the iron stained alteration,but abundant manganese-carbon and manganese dioxide in the wall rock.Based on the analysis of the spectral diagnostics of the primary altered mineral of Laochang ore deposit,this paper attempted some digital image processing versions that aim to stand out the manganese abnormal information, which could be a important clue for prospecting large size ore deposit like Laochang in Lancang region.