Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Application of Image Processing of Satelite Acquired Data for Mineral Explorations in Alluvium Deposits

Document Type : Original Research Paper

Authors
Iraj Navai
Simin Mehdizadeh Tehrani
Geological Survey of Iran- Remote Sensing Group
Abstract
From a review of existing literature, there seems to have been inadequate attention paid to date to the modulity of the units of Quaternary alluvial deposits and their relationship to their source rocks. This study was carried out with the aim of attempting to demonstrate to the geological community the possibility of using satellite multispectral data to bring to light certain aspect of this process.
For this purpose, a 54 kmx50 Km. Subscene of a cloud free Landsat TM image acquired in 1990 of the area around Rafsanjan in south Iran was selected. The area in this subscene is almost wholly covered by the 1:100,000 Map Produced by the Geological Survey of Iran in 1971. The analysis was carried out using the 6 bands digital "TM" data.
Of the various combinations attempted, the combination of TM bands 1,3 and 5 on the Red, Green and Blue was selected for optimum discrimination of geological deposits.
In this band combination, many lithological units were easily distinguishable from each other. In the case of alluvial deposits, it was most interesting to note the alluvial material examined, exhibited almost exactly the same colour as the source rocks from which they were derived. As a consequence, it was quite possible to differentiate the alluvial deposits according to their source.
The importance of such capability is of course most apparent in cases of minerals exploration. In other words, by distinguishing the source, it would be possible to delineate an area of high concentration of minerals derived from a source in which that is present in a low-grade and in disseminated form. Example of such situations that immediately come to mind are gold exploration in placer deposits and exploration for uranium minerals, whose solubility and subsequent redeposition in alluvial deposits makes them ideal for such a technique.
Furthermore, with view to the possibility of distinguishing such surface deposits, the utilization of such technique for exploration of building materials, especially those without the presence of undesirable contaminants such as gypsum or salt, becomes a necessity.
Subjects
Drury S. A. (1993), Image Interpretation in Geology. London, Allen and Unwin Publisher. GSI Rep. No. Yu/53- 1973. Mineral Exploration in Kerman Region;
Huang Xianfang et al. (1993). Interpretation of Remote Sensing Information related to Uranium Mineralization in Quaternary Covering area. Ninth Thematic Conference on Geologic Remote Sensing Pasadena, Calif. U. S. A. &- 11 Feb. 1993P. 815-820 of Proceeding.
Liu. J. G. (1991). Balance Contrast Enhancement Technique and its Application in Image Color Composition. Inter, Journal of Remote Sensing. Vol- 12. No. 10P. 2133-2151.
Srdic. A. et al. (1971). Geological Map of Rafsanjan1, 1:100,000.
Vahdati, F. Compiler (1992) Geological Map of Rafsanjan quadrangle. 1:250,000.
Scientific Quarterly Journal of Geosciences
Volume 4, Issue 13
Autumn 1994, Vol. 4, No. 13
Autumn 1994
Pages 14-23