Application of multi-source data synthetic analysis to Uranium exploration in Northern Hebei and Langshan area, inner Mongolia
Wang Wenjian, Cao Hongjing, Gao Shuhui
Airborne Survey and Remote Sensing center
China National Nuclear Corporation
ShijiaZhuang , China
Abstract
In this paper, the new discoveries and developments of multi-source data for synthetic geological interpretation are introduced to examine volcanic and sandstone types of uranium deposits in northern Hebei and Langshan area, Inner Mongolia. These multi-source data consist of space remote sensing information, airborne remote sensing and telemeter information and geological information, etc. The geological products obtained from synthetic interpretation and analysis present obvious effect in guiding uranium exploration. For examples, discovering of alternation zones in ore-controlling fault structures and gilding to look for mineral deposits; establishment of image models of volcano-tectonic type and relationship between these models and uranium mineralization; image model of stratabound sandstone type uranium deposit in the basin and are prospecting; synthetic interpretation correcting some misled judgements on fundamental geology, thus expanding the realm of ore prospecting and reducing the ore targets. All above- mentioned are dealt with in this paper.
Our center has made a synthetic interpretation for remote sensing geology in northern Hebei and Langshan area which are located in the transitional zone between north China Platform and Inner Mongolia geosyncline in order to make attempt to achieve new progress in exploration for upper Jurassic volcanic type uranium diposit in northern Hebei and Cretaceous sandstone type uranium deposit in Langshan area, Inner Mongolia by synthetic analysis of multi-source data (space remote sensing images, color infrared aerial photographs, airborne side-looking radar images, aerial energy spectrum measurements, aeromagnetic survey, and routine geology, etc. ) In recent years, the practice have shown that the synthetic interpretation have got out standing achievements to guide uranium exploration in two regions above mentioned and the expected purpose has been attained. Several typical examples of synthetic interpretation will be introduced in the following parts.
Discovery of alteration zones in ore-controlling fault structures
By synthetic interpretation for space and serial remote sensing images the framework of fault structures has been established in northern Hebei. The strikes of these fault structures can be divided into EW, NS, NE, NNE and NW directions in which the EW and NS directional faults are the important discoveries.
The EW and NS striking light-colored zones appeared in space remote sensing image, have been mutually proved by synthetic geological interpretation and identified by actual observation. Along the fualt structures, the slight negative landforms are displayed with about 2-3 km in width and are in parallel reappeared with 8-11 km at interval. The scattered material of broken and altered hydromicazed volcanic rock are widespread all over the low foothill, where vegetation is obviously sparse in contrast with the background. The light-colored zones appeared in TM visible light image, the bluish zones in TM 4,5,7 bands false-color composite image, the extremely bright-colored zones in TM (5/7 - 4/3) ratio image, the dark blue zones infrared false color image; and in aerial energy spectrum U, Th and K content images, the linear low field is in agreement with fault structures in position. The linear expanding gradient zones in aerial magnetic image coincide with fault structures for the most part. Aeromagnetic maps continued down to different depth show the faults are inclined to the north and extend to the north and extend to the depth more than 18 km.
