Geological information includes regional geological map, satellite remote sensing image and aerial remote sensing image, large-area aeromagnetic map, ground gravity data, known mineral resources, ore occurrence and mineralization distribution map, existing regional geological structure data, delineated metallogenic belt and mineral prediction data, etc.
The comprehensive study of geoscience information is exactly the same as other places in China, so it will not be described in detail.
Xinjiang is the first time in China to use low-density and very low-density geochemical exploration to do large-area surface scanning. Low-density geochemical exploration is mainly used to delineate large-scale nonferrous metal deposits on the surface or in shallow and medium-sized ore fields or belts in arid desert areas, and the sampling density is 15km2 1 point. Ultra-low density geochemical exploration is mainly used to delineate the most promising metallogenic belt in alpine mountain areas, provide prospecting information for large and super-large deposits, provide basic data for mineral resources prospect prediction and zoning, and delineate large or even medium-sized prospecting targets with sampling density of 35 ~ 40km 2 1 point.
In order to determine the sampling density, sampling medium, sampling weight and sample particle size, a method test was carried out before geochemical exploration scanning.
In the arid desert area, four mining areas, namely Kalatongke, Ashele, Abagong and Kalaxiangger, and four deposits, namely Kalatongke copper-nickel mine, salto Sea 1 gold mine, Hatu gold mine and Jinwozi gold mine, were selected for method tests, and supplementary method tests were carried out according to the specific conditions of the work area before each map started. The preliminary conclusion of the test is:
1. Wind-blown sand is the most serious interference factor in geochemical exploration in arid hilly Gobi area, and cuttings are the best sampling medium, with the best particle size of -4 ~+20 mesh. This kind of geographical landscape area generally has salt layer, which is a geochemical barrier. Sampling shall be carried out in the exposed area of bedrock as far as possible, and rat hole soil shall be taken as far as possible when covered. In anomaly inspection and evaluation, new methods for measuring soluble and volatile elements should be adopted as far as possible.
2. In the semi-arid and semi-humid mountainous areas, the sampling medium can be river system (main ditch) sediments, semi-arid areas can be coarse particles, and semi-humid areas can be fine particles. Lawn coverage in semi-humid middle and low mountainous areas is an urgent problem to be solved. We should collect samples of alluvial sand on the assembly line as far as possible, which can reflect the geological and mineral characteristics of the watershed.
3. The grid of1sample/1km2 can be used to find anomalies in various medium-sized ore fields, and even some small-sized ore fields can be found.
K-44-B and K-45-A were selected for the method test in the alpine mountain area, mainly in the western Tianshan Mountains. The preliminary conclusions of the test are as follows:
The (1) stream sediments were measured in the deep cutting area in the upper air of Zhongshan, and the average grid was 1 point /35 ~ 40km2. For areas with special difficulties, it can be diluted to 1 min /60 ~ 80km2. For shallow and medium-low mountainous areas, because the catchment area controlled by a single point is small, in order to make the catchment area controlled appropriately uniform, the sampling grid should be encrypted according to the metallogenic conditions.
The sampling points should be mainly arranged in the secondary ditch system, and the sampling medium is mainly medium-fine sand, with multiple points combined. In arid areas, samples should be taken as far as possible at the phreatic water gushing place; In the moraine development area, it is best to use subsurface silting micro-sand. Indoor processing generally requires that the sample weight is above 2.5kg and the particle size is less than 60 mesh.
(2) Looking for placer gold by heavy sand survey, you can take samples from the big river and its nearby Dagoukou. The weight of elutriation lime sand samples should be above 100g, so as to facilitate the analysis and mineral identification of lime sand.
(3) For the mapping method of very low density geochemical exploration, it is appropriate to sketch the contour map directly with the original data. The search method can circle the range of large anomalies, and the displacement of the anomaly center is less than 5km, but many small anomalies disappear and the anomalies are smoothed and averaged, and the effect is not ideal. This is because the sampling points are too sparse, and some anomalies may exist in the form of point anomalies.
According to the test results of this method, the unified requirements of geochemical scanning surface are formulated. Since the mid-1980s, the total working area has reached 527,000 km2, 39 elements in each sample have been analyzed, a great deal of prospecting information has been obtained, and outstanding geological prospecting results have been achieved. There are about 50,000 order element anomalies and about 4,000 comprehensive anomalies in the * * circle. After rapid tracking and evaluation in batches, a large number of deposits, occurrences and prospecting targets such as Sayi, Saidu, Salbulak, Axi, Wang Feng, Kangurtake, Xitan, Lingyuntan, Hongshijing Gold Mine, Keketale Lead-zinc Mine, Sayashike, Belekuduk Tin Mine, Chahansala Antimony Mine and Jiadi Mercury Mine in Zhifang section were discovered, which played a decisive role in completing scientific research and reserve prediction. As far as gold mines are concerned, the effect is the best. Major breakthroughs have been made in Altay and Tianshan areas. There are 1277 deposit anomalies, 1 1 gold belt, 8 1 prospecting target area, 15 general survey and evaluation base. Among them, Dolana Sayi, Saidu, Axi, Wangfeng, Kanggurtag and Xitan deposits have reached medium and large scale. There are three major changes in gold geological work in Xinjiang: from placer gold to more promising primary gold; From the single Carboniferous time pulse type to the multi-era multi-genetic type; From parts of western Junggar to Altay and Tianshan areas with good prospects. During the Seventh Five-Year Plan period, the proven gold reserves were more than twice that of the past 30 years, which made the ranking of Xinjiang's gold reserves rise from the 22nd in China to 14, and the annual gold output rose from the penultimate in China to the 9th, which quickly changed the backward appearance of Xinjiang's gold mines.