The Application of the TM data to the gold deposit prospecting
4. The Application of GIS to the TM Data and Polygenetic Geoinformation Processing of
Gold Deposit
First, the TM data and the other geoinformation should be projected to unidied
coordinate system - meaning of geometric registration processing; Secondly, the
registration data should give imagenization to from the synthesization image data
base of the polygenetic data; Finally, by the processing of the synthesixation of
polyenetic image, IHS transformation and the K - L transformation, we can analysis
the internal relation of gold deposit, TM data and the other polygenetic
geoinformation. For example, the complex of gold geochemical prospecting
anormaly and TM data could be used to find the relation between the gold mineratlization and linear or annular structure; the complex of gold anormaly, aeromagnetic data and TM data could be find the relation of gold mineralization with aeromagetic anormally gradient belt. The K-L transformation of the multi-element geochenical prospecting anormaly could be used to find the correlation gold and the other elements, etc. the complex of spatial trendency analysis image of ore-forming favouraility and remote sensing image could be directly perceived to reflect the spatial trendency variation of gold ore-forming favourability and spatial distribution of the gold prospecting.
5. Remote Sensing Prospecting Criteria And Prospecting Model Of Gold Deposit
There are five aspects of remote sensing which could reflect the information of gold deposit.
A. Line
- Some deep and large faulted structures controlling the boundary of tectonic units mainly show being major mega-lineament which control the distribution of gold ore -forming belts and gold mineralization centralization belts for example, the latitudinal transcrustic fracture of north laitude of 42o in Tianshan area, and the giant Tanlou fracture in the NE trend in Hunan -Jiangxi provinces.
- The slightly inferior regional major fracture lineament (belt) which interest the above -mentione lineaments and the intersected geologic masses always occur with ore-forming sub-belts and ore-forming regions.
- The inferior lineament which occur in the superimposed belts of the above-mentioned lineament belts control the distribution of the ore fields and the ore districts.
- The inferior lineaments which have small scale but high concentration and have relation with the comparatively larger structure are often the favourable location of occurance of he ore deposit and ore body.
B. Ring
The thermal ring fracture of magmatic emplacement and volcanic apparatus usually have close relation with gold deposits.
- The magmatic hydrothermal -type and the metamorphic hydrothermal-type gold depost generally occur in the periphery range of the 2-6kmof he thermal ring structure.
- The gold deposit which is related with volcanism are usually occur in the margin or center of the ring fracture formed by the apparatus.
C. Belt
It mainly means the host bed which generally is the remote sensing prospecting indicator of fine disseminated gold deposit.
D. Mass
It means the compression lens and lozenge - shaped structure formed by the intersection of fracture, gold despots usually occur in the pointed end of the lens and the acuteangel area of the lozenge -shaped structure-it shows that extensional are is favorable occurrence of gold deposits.
E.Colour
It mainly mean the colour tone are of strata, lithology and alteration information which is related with gold deposit.
The prospecting models of difference kinds of gold deposit are not alike, usually as following:
A. Quartz vein -type gold deposit: Complex of annular structure + deep fracture lineament belt + acuteangel area of lozenge - shaped structure + acidic and intermediate - acidic rock body + alteration information of gold mineralization + province.
B. Volcanic + type gold deposit : The volcanic - subvolcanic rocks above the old metamorphic basement series + deep linear fault mainly in NE trend + large or small annular image assemblage and the intersecting point with linear or annular small annular image assemblage and the intersecting point with linear or annular structure + geophysical - geochemical anormaly section + tectonoclastic altered rock or interstratified fracture belt. eg. Yelintou gold deposit in Zhejiang province, Qianhe gold deposit in Henan province.
C. Tectonic altered rock -type gold deposit : The complex of old terrane in special image of dark metamorphic rocks of island arc system + deep fracture and compressisonal ahear lineament belts in NE - Nne trend + multi -colour multiperiod metamorphic - migmatized - megmatic hydorthermal annular geologic body + complex of annular structure + medium geophysical - geochemical field + hydrothernmal tectonic altered rock (belt section). Eg. Jiaojia gold depoist in Shandong province.
D. Fine disseminated - type gold deposit : Linear fracture + complex of hydrothermal annular image geologic body + intersectuing joint of structure of NS and NE of NW in trend + anomalous altered fracture belt + geochemical anomaly of low - temperature assemblage. eg. Dongbeizai gold in Sichan province.
