CN104076393A - Recognizing method for concealed mineralization tectonic zone of granite type uranium deposit - Google Patents

Abstract

The invention relates to a geological survey method and particularly discloses a recognizing method for a concealed mineralization tectonic zone of granite type uranium deposit. The recognizing method comprises the first step of manufacturing a large-scale remote sensing structural interpretation map, the second step of selecting a structural alteration zone A beneficial to mineralization is selected on the large-scale remote sensing structural interpretation map, the third step of extracting chemical detection information to obtain a structural alteration zone B beneficial to mineralization, the fourth step of extracting physical detection information to obtain a structural alteration zone C beneficial to mineralization, and the fifth step of determining a preferred mineralization target region. As geology, physics, chemistry and remote sensing methods are combined, the deep mineralization beneficial section of uranium can be recognized accurately, and a basis is provided for uranium prospecting and preference prediction.

Description

A method for identifying concealed ore-forming structural belts of granite-type uranium deposits

technical field

The invention relates to a geological survey method, in particular to a method for identifying hidden ore-forming structural belts of granite-type uranium deposits.

Background technique

Granite-type uranium deposits are one of the four major types of uranium deposits in my country. For granite-type uranium deposits, only uranium-rich granite is not enough. Structural alteration zones play the role of ore-hosting and ore-conducting in granite-hydrothermal uranium deposits. It can provide a channel for the migration of ore liquid, and it can also provide a place for enrichment and integration of ore, and it is also a comprehensive reflection of mineralization information. The study of ore-forming structure is of great significance to understand the formation mechanism of ore-forming structure and the control effect of structure on the migration and enrichment of ore liquid. The metallogenic structural alteration zone is a part of the structural alteration zone, how to identify and detect the ore-forming structural alteration zone among numerous structural alteration zones is the key technology for surface prospecting. Therefore, the study of metallogenic structural alteration zones has guiding significance for ore prospecting.

The identification and detection methods of the granite-type uranium ore-forming structural belt are relatively simple in the existing technology. The southern granite region has complex terrain and lush vegetation. The identification of metallogenic structural belts is mainly based on gamma measurement, supplemented by other radioactive measurement methods. This is good for finding shallow metallogenic structural belts, but it is difficult to reflect deep mineralization. tectonic belt. Now it is more and more difficult to find ore deposits in deep areas, and it is very important to establish ore-forming structures, especially identification marks of deep-seated ore-forming structures, to search for granite-type uranium deposits. Therefore, it is necessary to further study the geo-physics-chemistry-telemetry method and select a set of effective method combinations for deep metallogenic structural belts.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for identifying hidden ore-forming structural belts of granite-type uranium deposits, which can achieve high identification accuracy for deep uranium ore-forming structural belts.

In order to solve the problems of the technologies described above, the technical solution provided by the present invention is:

A method for identifying hidden ore-forming structural belts of granite-type uranium deposits, comprising the following steps:

Step (1), making a large-scale remote sensing structure interpretation map;

Step (2), selecting structural alteration zone A favorable for mineralization on the large-scale remote sensing structural interpretation map;

Step (3), extracting chemical detection information to obtain a structural alteration zone B that is conducive to mineralization;

Step (4), extracting physical detection information to obtain structural alteration zone C favorable for mineralization;

Step (5), determining the preferred mineralization target area.

Described step (1) comprises

(1.1) Establish remote sensing interpretation signs of fault structures on remote sensing images;

(1.2) Mark the remote sensing interpretation marks of the fault structure on the remote sensing image to obtain a large-scale remote sensing interpretation structure map.

The remote sensing interpretation signs of the fault structure include: linearly arranged negative topography, linear valleys, linear tonal anomaly bands, and linear intermittently distributed negative topography.

The structural alteration zone A favorable for mineralization in the step (2) includes: ① the intersection of multiple groups of fault structures in the region, and the ore-forming structural belt is mainly tension-torsional, connecting regional ore-controlling structures; ② Multi-stage magmatic activity development sites, especially the late intermediate-basic dikes, fine-grained granite and other development areas; ③ hydrothermal alteration development areas, including early-mine muscovitation, alkali metasomatization, sericitization and other surface alterations and linear alteration development areas such as silicification, hematite mineralization, pyritization, and purple-black fluoritization during the ore-forming period; intersection complex.

Described step (3) comprises

(3.1) Deploy the chemical detection work area on the large-scale remote sensing structure interpretation map obtained in step (1), including: ① large and continuous uranium content, soil thermoluminescence anomaly area; ② overlapping and Anomalous distribution area of gradually enriched uranium content and strong anomalous concentration center of uranium content; ③ U, Mo, Be component combination anomaly and corresponding composite area of deep faulted structural belt;

(3.2) Draw the U component contour map, the Be component contour map, the Mo component contour map, and the soil thermoluminescence contour map in the chemical detection work area respectively, and select the abnormal area in the obtained drawing as Structural alteration zone B favorable for mineralization.

Described step (4) comprises

(4.1) Deploy the physical exploration work area on the large-scale remote sensing structural interpretation map obtained in step (1), including: there are a large number of mineralized anomalies, but there are few known structural alteration zones, and the distribution extends to the deep unknown area;

(4.2) Collect audio magnetotelluric sounding data and ground high-precision magnetic data in the physical detection work area; according to the audio magnetotelluric sounding inversion, the distribution characteristics of the underground medium resistivity and the characteristics of the surface magnetic field, combined with high-precision magnetic measurement curves The abnormal value appears, delimiting the structural alteration zone C which is favorable for mineralization.

Described step (5) comprises

The structural alteration zone A favorable for mineralization obtained in step (2), the structural alteration zone B favorable for mineralization obtained in step (3) and the structural alteration zone favorable for mineralization obtained in step (4) C are respectively marked on the large-scale remote sensing structural interpretation map, and together they form the optimal metallogenic target area, that is, the concealed ore-forming structural belt of granite-type uranium deposits.

The beneficial technical effects of the present invention are:

A method for identifying hidden ore-forming structural belts of granite-type uranium deposits provided by the present invention can accurately identify favorable sections of deep uranium ore-forming by combining geological, physical, chemical, and remote sensing methods, and is useful for uranium ore prospecting and optimal prediction. Provide evidence.

Detailed ways

The present invention is described in further detail below in conjunction with embodiment.

The application area of this embodiment is the Changpai-Xuetang'ao section in southern Guangxi, China (hereinafter referred to as "this area").

A method for identifying hidden ore-forming structural belts of granite-type uranium deposits provided by the present invention includes the following steps:

Step (1), making a large-scale remote sensing structure interpretation map.

(1.1) Establish remote sensing interpretation signs of fault structures on remote sensing images;

Using French Pleiades-1 satellite remote sensing images, by obtaining the fault structure features of ground objects, the remote sensing interpretation signs of fault structures are identified. The main fault structures in this area are three groups of NE-NE, NWW and near-North-South. Due to the different properties of fault structures in various aspects, they also show different characteristics in remote sensing images. The remote sensing interpretation signs of near-north-south fault structures are relatively concealed linear features, and have a relatively wide and gentle negative topography; The abnormal zone has obvious linear image features; the NWW trending fault structure is marked by remote sensing interpretation as deep and large linear valleys or linear intermittently distributed negative topography.

(1.2) Mark the remote sensing interpretation marks of the fault structure on the remote sensing image to obtain a large-scale remote sensing interpretation structure map.

Mark the remote sensing interpretation marks of the fault structure obtained above on the remote sensing image, and complete the remote sensing interpretation structure map of the whole area at 1:25000 and the eastern part of the area at 1:10000.

In step (2), select structural alteration zone A favorable for mineralization on the large-scale remote sensing structural interpretation map.

Structural alteration zone A favorable for mineralization includes: ① the intersection of multiple groups of fault structures in the region, and the ore-forming structural belt is mainly tension-torsion, connecting regional ore-controlling structures; ② multi-stage magmatic activity development site, Especially in the areas where intermediate-basic dikes and fine-grained granite developed in the late stage; ③The areas where hydrothermal alteration developed, including muscovitation, alkali metasomatization, sericitization and other planar alterations in the early mineralization period and silicification, hematite Mineralization, pyritization, purple-black fluoritization and other linear alteration development areas; ④ different types of mineralization structural plane development sites, such as different lithological contact sites, structural alteration zone intersection composite sites.

The Changpai section of this area is located in the south of the Mianhuakeng deposit, and intersects with the Youdong fault. The main ore-bearing structural belts are zone a, zone b and zone c. Zone a is an important ore storage structure in this area, controlling the oil cave deposit and many anomalous points. In zone a, silicified cataclysmic rocks, cataclysmic granites, siliceous veins and intermediate-basic veins can be seen, and in the oil cave deposits, Obvious uranium mineralization is seen in the Youdong-Tuotongling area. The structures in the south of belt b and c are relatively large in scale, and hydrothermal alteration is well developed. It can be seen from the field observation that the southern parts of the b-zone and c-zone structural belts are distributed along deep trenches and extend far. An obvious siliceous skeleton can be seen in the southern part of the b-zone, which is composed of siliceous veins, silicified cataclysmic rocks and strongly altered cataclatic granites, and obvious gray-green hydromica and reddish-brown hematite mineralization alterations are seen; in the southern part of the c-zone, the field Although no obvious hydrothermal alteration was observed, only a small amount of siliceous veinlets and local alterations were observed, but the c-zone has branches and bends along the trend.

The Xuetang'ao section of this area is located in the northern part of the Shuishi deposit, in the clamping area between the Youdong fault zone and the Mianmiankeng fault zone. There are near-north-south structural alteration zones such as d zone and e zone developed in this area, and the alteration zones have a certain scale. Hydrothermal alteration is developed in this area, gray-green hydromicitization and reddish-brown hematite are mostly seen on the surface, and fleshy red siliceous veins with a width of about 1m can be seen locally.

Therefore, zone a, zone b, zone c, zone d, and zone e are selected as the structural alteration zone A favorable for mineralization.

In step (3), the chemical detection information is extracted to obtain the structural alteration zone B favorable for mineralization.

(3.1) Deploy the chemical detection work area on the large-scale remote sensing structure interpretation map obtained in step (1), including: ① large and continuous uranium content, soil thermoluminescence anomaly area; ② overlapping and The anomalous distribution area of gradually enriched uranium content and the strong anomalous concentration center of uranium content; ③ U, Mo, Be component combination anomalies and corresponding composite areas of deep faulted structural belts;

The Changpai section of this area intersects with the ore-bearing structural oil cave fault zone, and there are obvious chemical detection anomalies in the west of the Changpai section and the Xuetang'ao section. The Xuetang'ao section is located between the Mianmiankeng fault zone and the Youdong fault zone, where multi-phase magmatic activities developed, with multiple nearly east-west lamprophyre veins and granite porphyry veins, and alkali metasomatites developed; Xuetang'ao Significant chemical detection anomalies are visible in the eastern part of the segment.

To this end, the first chemical detection work area was deployed in the west of the Changpai section and the Xuetang'ao section, and samples were taken at a line spacing of 100m and a point spacing of 20m. A total of 55 survey lines and 4,817 survey points were set. Deploy the second chemical detection work area in the east of the Xuetang'ao section, and take samples at a line spacing of 100m and a point spacing of 20m. A total of 46 survey lines and 7,800 point survey points need to be set up. The content information and thermoluminescence information of U, Mo, and Be elements were sampled at the selected measuring points.

(3.2) Draw the U component contour map, the Be component contour map, the Mo component contour map, and the soil thermoluminescence contour map respectively in the chemical detection work area, and select the abnormal area on the resulting drawing as Structural alteration zone B favorable for mineralization.

U component contour map, Be component contour map, Mo component contour map and soil thermoluminescence contour map were made with Sufer software. On the U component contour map, the U average content of all measuring points is used as the background value, and the sum of the background value plus 2 times the standard deviation is used to determine the abnormal lower limit value of the U element, and the area greater than the abnormal lower limit value is delineated as U abnormal area. Similarly, delineate Be anomalous areas, Mo anomalous areas, and soil thermoluminescence anomalous areas.

The ore-bearing structural belts such as the f zone and g zone of the Changpai section, the h zone and the i zone of the Xuetang'ao section have obvious combination anomalies of U, Mo, and Be components and soil thermoluminescence anomalies. Large, progressively enriched uranium component anomalous distribution pattern and 3 uranium component anomalous concentration centers, all of these locations are favorable ore-forming areas.

Therefore, the f-zone, g-zone, h-zone and i-zone are selected as structural alteration zone B that is favorable for mineralization.

In step (4), physical detection information is extracted to obtain a structural alteration zone C favorable for mineralization.

(4.1) Deploy the physical exploration work area on the large-scale remote sensing structural interpretation map obtained in step (1), including: there are a large number of mineralized anomalies, but there are few known structural alteration zones, and the distribution extends to the deep unknown area;

According to the fact that there are a large number of anomalies in this area, but there are few known structural alteration zones, and the deep extension is unknown, a total of 7 AMT survey lines and 7 high-precision magnetic survey lines were designed. The total length of the high-precision magnetic survey line is 41.5km, the point distance is measured at 10m, and a total of 4150 sampling points need to be set; the total length of the AMT survey line is 41.5km, and the point distance is measured at 20m, and a total of 2075 sampling points need to be set.

(4.2) Collect audio-frequency magnetotelluric sounding (AMT) data and surface high-precision magnetic data in the physical detection work area; according to the audio-frequency magnetotelluric sounding inversion, the resistivity distribution characteristics of the underground medium and the surface magnetic field characteristics, combined with high-precision The abnormal value of the magnetic survey curve delineates the structural alteration zone C that is conducive to mineralization.

The results of physical exploration and measurement show that a large number of near-north-south structural belts are developed in this area, such as j-zone, k-zone, m-zone, and n-zone, and their cross-combination can be seen locally. Especially in the northern and southern regions of j-belt and k-belt, the deep extension scale is relatively large, and the vertical depth can generally reach 1000m, which is very favorable for the formation of uranium mineralization. There are also a large number of nearly north-south hidden structural belts developed in this area, which can extend to about 1000m in depth. In particular, the composite parts of different fault structures are favorable space for uranium mineralization, and the most important one is the deep contact part between p zone and q zone.

Therefore, the deep contact parts of j-zone, k-zone, m-zone, n-zone and p-zone and q-zone are selected as the structural alteration zone C favorable for mineralization.

Step (5), determining the preferred mineralization target area.

The structural alteration zone A favorable for mineralization obtained in step (2), the structural alteration zone B favorable for mineralization obtained in step (3) and the structural alteration zone favorable for mineralization obtained in step (4) C is marked on the large-scale remote sensing structural interpretation map, and together they form the optimal metallogenic target area, that is, the concealed ore-forming structural belt of granite-type uranium deposits.

Then the a-band, b-band, c-band, d-band, e-band, f-band, g-band, h-band, i-band, j-band, k-band, m-band, n-band, p-band and q-band deep contact parts and other structures These belts together constitute the buried ore-forming structural belt of granite-type uranium deposits required by the present invention.

Claims (7)

1. the latent ore-forming structure band recognition methods of granite type U-ore, is characterized in that: it comprises the following steps:

Step (1), makes large scale remote sensing structure explanation figure;

Step (2) is chosen the structure alteration zone A that is conducive to into ore deposit on large scale remote sensing structure explanation figure;

Step (3), extraction chemical probing information obtains being conducive to into the structure alteration zone B in ore deposit;

Step (4), extracts physical detection information obtains being conducive to into the structure alteration zone C in ore deposit;

Step (5), determines and is preferably target area, ore deposit.

2. the latent ore-forming structure band recognition methods of a kind of granite type U-ore according to claim 1, is characterized in that: described step (1) comprises

(1.1) on remote sensing image, set up rift structure remote sensing interpret tag;

(1.2) rift structure remote sensing interpret tag is marked on remote sensing image, obtain large scale Remote Sensing Structural Interpretation figure.

3. the latent ore-forming structure band recognition methods of a kind of granite type U-ore according to claim 2, is characterized in that: described rift structure remote sensing interpret tag comprises: the negative land form of the linear alignment, linear pattern cheuch, linear tonal anomaly band, the interrupted negative land form distributing of linearity.

4. the latent ore-forming structure band recognition methods of a kind of granite type U-ore according to claim 3, it is characterized in that: the structure alteration zone A that is conducive to into ore deposit in described step (2) comprises: 1. many group rift structures position that crosses on region, and ore-forming structure band is to open the property turned round as main, connected region ore-controlling structure; 2. time magmation of many phases is grown Mafic Dikes, granitello etc. in position, particularly late period and is grown location; 3. location is grown in hydrothermal alteration, comprises the line style alteration growth locations such as the face type alterations such as ore deposit muscovitization in early stage, alkali explanation, sericitization and metallogenic period silication, haematization, pyritization, atropurpureus fluorite; 4. dissimilar metallogenetic structure surface development position, as different lithology contact site, structure alteration zone intersect compound position.

5. the latent ore-forming structure band recognition methods of a kind of granite type U-ore according to claim 4, is characterized in that: described step (3) comprises

(3.1) the large scale remote sensing structure explanation figure deploy chemical probing workspace obtaining in step (1), comprising: 1. large, the good uranium component of continuity of area, soil thermoluminescence exceptions area; 2. fit and the abnormal distributive province of uranium component of progressively concentrating and the stronger abnormal concentration center of uranium component; 3. U, Mo, the abnormal recombination region corresponding to deep component in fault structure zone of Be component combination;

(3.2) draw respectively U component isogram, Be component isogram, Mo component isogram, the soil thermoluminescence isogram of chemical probing workspace, the abnormal area in the drawing of gained is chosen for to the structure alteration zone B that is conducive to into ore deposit.

6. the latent ore-forming structure band recognition methods of a kind of granite type U-ore according to claim 5, is characterized in that: described step (4) comprises

(4.1) the large scale remote sensing structure explanation figure deploy physical detecting workspace obtaining in step (1), comprising: have a large amount of mineralising abnormity point, but known configuration alteration zone is less, and extends spread region in confused situation to deep;

(4.2) on physical detecting workspace, gather Audio Magnetotelluric Souding data and ground high-precision magnetic survey data; According to underground medium resistivity distribution feature after Audio Magnetotelluric Souding inverting and earth's surface magnetic signature, the value that combined high precision magnetic survey curve occurs is abnormal, and delineation is conducive to into the structure alteration zone C in ore deposit.

7. the latent ore-forming structure band recognition methods of a kind of granite type U-ore according to claim 6, is characterized in that: described step (5) comprises

The structure alteration zone C that is conducive to into ore deposit that the structure alteration zone B that is conducive to into ore deposit that the structure alteration zone A that is conducive to into ore deposit, the step (3) that step (2) is obtained obtains obtains with step (4) marks respectively on large scale remote sensing structure explanation figure, common composition is preferably target area, ore deposit, i.e. the latent ore-forming structure band of granite type U-ore.