CN108335223B - A kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method - Google Patents

Abstract

The invention belongs to the technical field of uranium ore geological research, and specifically discloses a technical method for comprehensive evaluation of sandstone-type uranium ore. The method includes the following steps: step 1, determining the favorable geological background and ore-forming environment for uranium ore-forming; step 2, determining Sedimentary subfacies or microfacies and spatial distribution of the prospecting target layer; step 3, identification and positioning of favorable sand bodies for uranium ore-forming; step 4, comprehensive extraction of favorable ore-forming information; step 5, delineate favorable ore-forming areas, and comprehensively evaluate the formation Ore potential; each step of the present invention is an irreversible homeopathic method, which can efficiently, quickly and objectively evaluate the uranium ore-forming potential in a region; the analysis of uranium geological background and ore-forming environment is the primary factor, and the analysis of uranium source conditions is the most important If there is no uranium source condition in this area, no uranium deposit will exist no matter how good the other conditions are; by analyzing the ore-forming geological background and ore-forming environment, the favorable ore-forming geological conditions have been determined.

Description

A comprehensive evaluation method for sandstone-type uranium deposits

technical field

The invention belongs to the technical field of uranium ore geological research, and in particular relates to a technical method for comprehensive evaluation of sandstone-type uranium ore.

Background technique

Sandstone-type uranium deposits are basically blind mines deeply buried in sedimentary basins, and most of the exposed uranium ore bodies have been denuded and leached, making them useless. The most direct and effective way to find this type of uranium ore body is to expose it by drilling, but the economic cost is too high, which is not in line with the current economic development of our country. In order to search for sandstone-type uranium deposits accurately and efficiently, the more effective method at present is to make full use of the data (including geology, drilling, logging, seismic, geophysical, chemical, etc.) remote sensing), combined with the ground radioactive measurement, aerial release and aeromagnetic measurement data of the Ministry of Nuclear Industry, by analyzing the geological characteristics of uranium mineralization in this area, extracting information that is beneficial to uranium ore prospecting, initially delineating the prospect area, and then through a small amount of Drilling verification, further analysis of metallogenic geological characteristics and prospecting information, gradually narrowing the scope of exploration, and finally locking the target area.

This method is based on the research of certain uranium deposits. It makes full use of previous data and combines the necessary geological work to quickly extract favorable information for ore prospecting and comprehensively evaluate the uranium mineralization potential of an area in an economical and efficient manner. In the era of big data, it is an effective method to use comprehensive information to find ore.

Contents of the invention

The purpose of the present invention is to provide a technical method for comprehensive evaluation of sandstone-type uranium deposits. The method studies uranium ore-forming characteristics, extracts ore-prospecting information, delineates uranium ore-forming prospect areas, and objectively evaluates the Regional uranium mineralization potential.

The technical scheme that realizes the object of the present invention: a kind of sandstone type uranium ore comprehensive evaluation technical method, this method comprises the steps:

Step 1, determine the favorable geological background and ore-forming environment for uranium mineralization;

Step 2, determining the sedimentary sub-facies or micro-facies and spatial distribution of the prospecting target layer;

Step 3, identification and location of favorable sand bodies for uranium mineralization;

Step 4, comprehensive extraction of favorable mineralization information;

Step 5, delineate favorable areas for mineralization, and comprehensively evaluate the metallogenic potential.

Described step 1 comprises the following steps:

Step 1.1 Analyze the uranium source conditions of the basement erosion source area around the basin and the uranium source conditions of the ore-bearing target layer and its overlying strata within the basin.

Step 1.2 Determine favorable geological conditions for uranium mineralization through comprehensive analysis of structure-sedimentation-paleoclimate evolution.

In the above step 1.1, the analysis of uranium source conditions is the primary and necessary element in the evaluation of uranium mineralization potential. It is necessary to analyze the uranium source conditions in the basement erosion source area around the basin, and to analyze the ore-bearing target layer inside the basin and its upper surface. Uranium source conditions for overburden construction.

The data of uranium source condition analysis can use the measured data and airborne data, not only to analyze whether the geological body contains uranium (5×10 ^-6 ~10×10 ^-6 ) or rich uranium (>10×10 ^-6 ), but also Analyze several key parameters such as ancient uranium content (Gui), active uranium content (Hui) and uranium migration coefficient (Bi), and the calculation formula is shown in formula (1)\(2)\(3);

Hui=Gui-Ui (2)

Bi＝Hui/Gui (3)

Thi—actually measured thorium content; Ui—actually measured uranium content; — Geological unit U/Th average.

Among them, the positive value of active uranium content (Hui) indicates that the point provides the proportion of active uranium for other sections, and the negative value indicates that the point accepts the enrichment of uranium in the later stage; when the uranium transfer coefficient (Bi) is greater than 1, the point has uranium Move in and enrich, and vice versa show the move out and depletion of uranium.

In step 1.2, it is necessary to analyze whether there is stable structural subsidence and relatively humid paleoclimate during the deposition period of the prospecting target layer to ensure that the target layer has stable and continuous sand body deposition. The body is rich in organic matter such as carbon chips and coal threads, and the organic carbon content should be >0.2%; the ore-bearing target layer should have stable structural uplift and relatively dry paleoclimatic conditions in the later stage of sedimentary diagenesis, and the buried depth of the target layer should be 1,000 meters It is suitable to be shallow, and there is a partial outcrop at the edge of the basin, which can provide a water inlet for the penetration of uranium-containing and oxygen-containing water; there must be a certain tilting effect in the process of structural uplift, resulting in the development of a stable slope zone in the target layer, and the slope The angle is generally less than 10°, and the slope length is >7km, which can provide sufficient time for the development of the interlayer oxidation zone; strong structural uplift should not occur in the late stage of uranium mineralization, which may cause the ore body to be uplifted to surface denudation and damage. The sandstone-type uranium mineralization period often coincides with the long-term lack of sedimentary strata in this area and the paleoclimate of the same period is dry, which is an important geological sign for analyzing the uranium mineralization period.

In the step 2, it is necessary to fully collect the drilling data and well logging data, and then combine the surface outcrops to establish the identification marks of sedimentary facies, subfacies and microfacies; through the cross-section of multiple boreholes, the development of sedimentary facies is compared and analyzed. On the basis of the sand body thickness contour map and sand content contour map, the sedimentary facies map is further compiled; the relationship between sedimentary facies and uranium mineralization is studied to determine the ore-controlling sedimentary facies. The most favorable sedimentary facies for sandstone-type uranium deposits are braided river and braided river delta facies, followed by meandering river and meandering river delta facies.

Described step 3 comprises the following steps:

Step 3.1 Determine the thickness of the favorable sand body in the prospecting target layer

Step 3.2 Determine the favorable sand content of the prospecting target layer

Step 3.3 Determine the favorable oxidation sand rate of the prospecting target layer

Step 3.1 On the basis of the sand body thickness equivalent map prepared in the above step 2, analyze the relationship between sand body thickness and uranium mineralization, and establish favorable sand body thickness and spatial distribution;

Step 3.2 On the basis of the equivalent map of sand content in the above step 2, analyze the relationship between sand content and uranium mineralization, and establish favorable sand content and spatial distribution;

In the step 3.3, it is necessary to compile the equivalent map of the oxidized sand ratio of the target layer. Among them, 0 represents the original gray reducing environment in the gray clastic sedimentary formation, and represents the original gray reducing environment in the red clastic sedimentary formation, and represents the reducing environment in which oil and gas transformed the original red formation into a gray construction. Analyze the relationship between oxidized sand rate and uranium mineralization, and establish favorable oxidized sand rate and spatial distribution.

Described step 4 comprises the steps:

Step 4.1 extracts favorable information on uranium mineralization under geological conditions;

Step 4.2 extracts favorable information for uranium ore prediction from aerial release, geophysical prospecting, geochemical prospecting, remote sensing and other data.

The favorable geological conditions extracted in the step 4.1 include the channel sedimentary subfacies, the distribution area of the stable slope zone of the target layer, the distribution area of the favorable sand body thickness of the target layer, the distribution area of the favorable sand content rate of the target layer, and the favorable oxidation sand rate of the target layer. distribution area.

The favorable prediction information extracted in the step 4.2 includes the airborne uranium enrichment area, the active uranium enrichment area and the uranium depletion area, the ground radioactive measurement U content abnormal area, the ore-controlling folds and fractures jointly interpreted by aeromagnetic and gravity, Outlier distribution area of soil radon gas measurement.

The step 5 mentioned above is to use ArcGIS software or MapGIS software to realize the conversion and extraction of favorable geological information and prediction elements for mineralization, delineate favorable mineralization areas through MRAS software and man-machine joint, and analyze the favorable metallogenic conditions and unfavorable factors in the area , and finally realize the objective, accurate and efficient evaluation of regional uranium mineralization potential.

The beneficial technical effects of the present invention are:

1. Each step of the present invention is an irreversible homeopathic method, which can efficiently, quickly and objectively evaluate the uranium ore-forming potential in a region;

2. The analysis of uranium geological background and metallogenic environment is the primary factor, among which the analysis of uranium source conditions is the most important. If there is no uranium source condition in this area, then no matter how good the other conditions are, there will be no uranium deposits;

3. Through the analysis of the metallogenic geological background and the metallogenic environment, the favorable metallogenic geological conditions are determined, and then the material, chemical remote and air release data are fully used to extract the prediction elements, which not only saves costs, shortens the cycle, but also accurately delineates the mineralization. Comprehensively evaluate the ore-forming potential of uranium, and provide the basis for exploration and deployment of uranium ore prospecting.

Detailed ways

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

The technical scheme that realizes the object of the present invention: a kind of sandstone type uranium ore comprehensive evaluation technical method, this method comprises the steps:

Step 1, determine the favorable geological background and ore-forming environment for uranium mineralization;

Step 2, determining the sedimentary sub-facies or micro-facies and spatial distribution of the prospecting target layer;

Step 3, identification and location of favorable sand bodies for uranium mineralization;

Step 4, comprehensive extraction of favorable mineralization information;

Step 5, delineate favorable areas for mineralization, and comprehensively evaluate the metallogenic potential.

Described step 1 comprises the following steps:

Step 1.1 Analyze the uranium source conditions of the basement erosion source area around the basin and the uranium source conditions of the ore-bearing target layer and its overlying strata within the basin.

Step 1.2 Determine favorable geological conditions for uranium mineralization through comprehensive analysis of structure-sedimentation-paleoclimate evolution.

In the above step 1.1, the analysis of uranium source conditions is the primary and necessary element in the evaluation of uranium mineralization potential. It is necessary to analyze the uranium source conditions in the basement erosion source area around the basin, and to analyze the ore-bearing target layer inside the basin and its upper surface. Uranium source conditions for overburden construction.

The data of uranium source condition analysis can use the measured data and airborne data, not only to analyze whether the geological body contains uranium (5×10 ^-6 ~10×10 ^-6 ) or rich uranium (>10×10 ^-6 ), but also Analyze several key parameters such as ancient uranium content (Gui), active uranium content (Hui) and uranium migration coefficient (Bi), and the calculation formula is shown in formula (1)\(2)\(3);

Hui=Gui-Ui (2)

Bi＝Hui/Gui (3)

Thi—actually measured thorium content; Ui—actually measured uranium content; — Geological unit U/Th average.

Among them, the positive value of active uranium content (Hui) indicates that the point provides the proportion of active uranium for other sections, and the negative value indicates that the point accepts the enrichment of uranium in the later stage; when the uranium transfer coefficient (Bi) is greater than 1, the point has uranium Move in and enrich, and vice versa show the move out and depletion of uranium.

In step 1.2, it is necessary to analyze whether there is stable structural subsidence and relatively humid paleoclimate during the deposition period of the prospecting target layer to ensure that the target layer has stable and continuous sand body deposition. The body is rich in organic matter such as carbon chips and coal threads, and the organic carbon content should be >0.2%; the ore-bearing target layer should have stable structural uplift and relatively dry paleoclimatic conditions in the later stage of sedimentary diagenesis, and the buried depth of the target layer should be 1,000 meters It is suitable to be shallow, and there is a partial outcrop at the edge of the basin, which can provide a water inlet for the penetration of uranium-containing and oxygen-containing water; there must be a certain tilting effect in the process of structural uplift, resulting in the development of a stable slope zone in the target layer, and the slope The angle is generally less than 10°, and the slope length is >7km, which can provide sufficient time for the development of the interlayer oxidation zone; strong structural uplift should not occur in the late stage of uranium mineralization, which may cause the ore body to be uplifted to surface denudation and damage. The sandstone-type uranium mineralization period often coincides with the long-term lack of sedimentary strata in this area and the paleoclimate of the same period is dry, which is an important geological sign for analyzing the uranium mineralization period.

In the step 2, it is necessary to fully collect the drilling data and well logging data, and then combine the surface outcrops to establish the identification marks of sedimentary facies, subfacies and microfacies; through the cross-section of multiple boreholes, the development of sedimentary facies is compared and analyzed. On the basis of the sand body thickness contour map and sand content contour map, the sedimentary facies map is further compiled; the relationship between sedimentary facies and uranium mineralization is studied to determine the ore-controlling sedimentary facies. The most favorable sedimentary facies for sandstone-type uranium deposits are braided river and braided river delta facies, followed by meandering river and meandering river delta facies.

Described step 3 comprises the following steps:

Step 3.1 Determine the thickness of the favorable sand body in the prospecting target layer

Step 3.2 Determine the favorable sand content of the prospecting target layer

Step 3.3 Determine the favorable oxidation sand rate of the prospecting target layer

Step 3.1 On the basis of the sand body thickness equivalent map prepared in the above step 2, analyze the relationship between sand body thickness and uranium mineralization, and establish favorable sand body thickness and spatial distribution;

Step 3.2 On the basis of the equivalent map of sand content in the above step 2, analyze the relationship between sand content and uranium mineralization, and establish favorable sand content and spatial distribution;

In the step 3.3, it is necessary to compile the equivalent map of the oxidized sand ratio of the target layer. Among them, 0 represents the original gray reducing environment in the gray clastic sedimentary formation, and represents the original gray reducing environment in the red clastic sedimentary formation, and represents the reducing environment in which oil and gas transformed the original red formation into a gray construction. Analyze the relationship between oxidized sand rate and uranium mineralization, and establish favorable oxidized sand rate and spatial distribution.

Described step 4 comprises the steps:

Step 4.1 extracts favorable information on uranium mineralization under geological conditions;

Step 4.2 extracts favorable information for uranium ore prediction from aerial release, geophysical prospecting, geochemical prospecting, remote sensing and other data.

The favorable geological conditions extracted in the step 4.1 include the channel sedimentary subfacies, the distribution area of the stable slope zone of the target layer, the distribution area of the favorable sand body thickness of the target layer, the distribution area of the favorable sand content rate of the target layer, and the favorable oxidation sand rate of the target layer. distribution area.

The favorable prediction information extracted in the step 4.2 includes the airborne uranium enrichment area, the active uranium enrichment area and the uranium depletion area, the ground radioactive measurement U content abnormal area, the ore-controlling folds and fractures jointly interpreted by aeromagnetic and gravity, Outlier distribution area of soil radon gas measurement.

The step 5 mentioned above is to use ArcGIS software or MapGIS software to realize the conversion and extraction of favorable geological information and prediction elements for mineralization, delineate favorable mineralization areas through MRAS software and man-machine joint, and analyze the favorable metallogenic conditions and unfavorable factors in the area , and finally realize the objective, accurate and efficient evaluation of regional uranium mineralization potential.

The beneficial technical effect of the present invention is that each step of the present invention is an irreversible homeopathic method, which can efficiently, quickly and objectively evaluate the uranium mineralization potential of a region. The analysis of uranium geological background and metallogenic environment is the primary factor, among which the analysis of uranium source conditions is the most important. If there is no uranium source condition in this area, then no matter how good the other conditions are, there will be no uranium deposits; Based on the geological background and metallogenic environment, the favorable geological conditions for mineralization have been determined, and then the data of physicochemical remote sensing and aerial release are fully used to extract the prediction elements, which not only saves costs, shortens the cycle, but also accurately delineates favorable areas for mineralization, and comprehensively evaluates The mineralization potential of uranium provides exploration and deployment basis for uranium prospecting work.

Example

Taking the Binxian-Changwu area on the southern edge of the Ordos Basin as an example, a kind of sandstone-type uranium deposit comprehensive evaluation technical method provided by the present invention is described in detail.

The tectonics of the Binxian-Changwu area are located at the transitional part of the secondary tectonic unit Yi-Shaan slope and Weibei uplift in the Ordos Basin. The exposed sedimentary cap rocks are developed from bottom to top with Upper Triassic, Middle Jurassic Yan'an Formation, Zhiluo Formation and Anding Formation, Lower Cretaceous, Neogene and Quaternary, and the Lower Jurassic Fuxian Formation, Upper Jurassic Jurassic Fenfanghe Formation, Upper Cretaceous and Paleogene. The lower member of the Zhiluo Formation is the main ore-bearing target layer, and the ore-bearing lithology is mainly gray feldspathic quartz sandstone rich in charcoal and pyrite, followed by gray-green sandstone. The bottom of the ore-bearing layer is thick gray mudstone at the top of the Yan'an Formation, and the top of the ore-bearing layer is thick purple-red mudstone in the upper Zhiluo Formation, which has a favorable structure of "mud-sand-mud" uranium mineralization. The unfavorable factor is that the ore-bearing layer is subjected to various effects such as basin caprock folding and extrusion, diagenetic compaction, and later fluid reformation, resulting in complex and diverse epigenetic alteration of sand bodies, and uranium mineralization is also a multi-stage and multiple action. In addition, the vertical and horizontal landforms and valleys have brought certain difficulties to the exploration of uranium deposits in the southern margin of the Ordos Basin. The present invention is also more suitable for areas with complex geological conditions and certain difficulties in geological exploration, and is a technical method for comprehensively analyzing uranium ore-forming potential quickly and effectively by making full use of various data.

A technical method for comprehensive evaluation of sandstone-type uranium ore provided by the present invention, the method comprises the following steps:

Step 1. Determine the favorable geological background and ore-forming environment for uranium mineralization

Step 1.1 According to the material composition, structure and structure of the sand body clastics in the ore-bearing target layer, and the composition and occurrence of the gravel at the bottom, it is determined that the sediment source and uranium source mainly come from the southwest and west of the basin, among which the North Qinling area in the southwest is distributed There are large areas of intermediate-acid granites, migmatites and metamorphic rocks in the early Yanshan period, the uranium content is (2.2-8.6)×10 ^-6 , and the leaching rate is 43%-54%. The uranium source conditions in the erosion source area of the basin are good; -The average uranium content of formations in the Changwu area is 1.99×10 ^-6 , of which the uranium content of the primary gray sandstone of the Zhiluo Formation is (4.72～9.01)×10 ^-6 , and the uranium content of the gray-green sandstone of the Zhiluo Formation is (2.19～2.62) ×10 ^-6 , the gray-white sandstone has a uranium content of 3.45×10 ^-6 , and the uranium loss is obvious compared with the gray sandstone. It shows that the uranium source derived from the Zhiluo Formation is also quite abundant, which is also favorable for the formation of epigenetic sandstone-type uranium deposits.

Step 1.2 comprehensively analyzes uranium mineralization conditions through structure-sedimentation-paleoclimate. The Mesozoic and Cenozoic periods in the southern margin of the Ordos Basin experienced two periods of subsidence, five periods of uplift, and one period of peripheral faulting activity. Subsidence period: Yanchang period and Fenfanghe period; uplift period: end of Yanchang period, end of Yan'an period, end of Zhiluo period, end of Fenfanghe period and end of Zhidan period; surrounding fault depression activity: Xishan period.

During the subsidence period, the early Zhiluo paleoclimate was humid, with braided fluvial facies developed, the single layer thickness of the sand body was 5-15m, the cumulative thickness was generally 10-50m, and the organic carbon content of the primary gray sand body was 0.3%-1.1%. However, in the same period, it was controlled by the nearly east-west parallel folds inherited from the Yan'an Formation, and the thicker sand bodies were mainly distributed in the syncline, showing a nearly east-west distribution. In short, favorable sandbody conditions developed during the depositional period.

Two long-term uplift periods from the end of Zhiluo to the early Early Cretaceous and from the early Late Cretaceous to the Neogene resulted in intermittent sedimentation at the same time. During this period, the paleoclimate was relatively dry, and the ore-bearing target strata were outcropped at the edge of the basin or in areas with structural skylights. It is beneficial to the penetration of uranium-containing and oxygen-containing water, and an interlayer oxidation zone develops in the lower member of the Zhiluo Formation. From the late Zhiluo period to the early Cretaceous period, the Binxian-Changwu area showed a structural pattern of high in the north and low in the south, high in the east and low in the west, and an interlayer oxidation zone from north to south developed along the northern uplift; It is high in the west and low in the west, high in the south and low in the north, and develops an interlayer oxidation zone from south to north. During this period, multiple stages of oil and gas reduction alteration and acid fluid kaolinization alteration developed, resulting in complex and changeable fronts of the interlayer oxidation zone in the southern margin of the Ordos Basin, and it is still difficult to control the distribution of the fronts. The developed interlayer oxidation zone is generally controlled by the slope belts on both wings of the syncline, and the uranium mineralization conditions in the syncline developed area are better.

Step 2, determine the sedimentary sub-facies or micro-facies and spatial distribution of the prospecting target layer

Through drilling core records, log curve shape comparison, geological outcrop observation, and drill hole profile analysis, it is determined that the lower member of the Zhiluo Formation in the Binxian-Changwu area mainly develops braided fluvial deposits. Based on the statistics of 152 boreholes in the area, the sand body thickness and sand content contour maps of the lower Zhiluo Formation were compiled, and the sand body thickness, sand content rate and identification marks of the subfacies of the braided river were compiled. Divide the channel subfacies, floodplain subfacies and channel subfacies, and compile the sedimentary facies map, in which the sand content rate of the main channel is >70%.

Step 3: Identification and location of favorable sand bodies for uranium mineralization

Step 3.1 Determine the thickness of the favorable sand body in the prospecting target layer

Step 3.1 On the basis of the equivalent map of sand body thickness prepared in the above step 2, analyze the relationship between uranium mineralization and sand body thickness, and establish that the sand body thickness within the range of 20-50m is a favorable area for mineralization;

Step 3.2 On the basis of the equivalent map of sand content in the above step 2, analyze the relationship between uranium mineralization and sand content, and establish that the sand content in the range of 60% to 90% is a favorable area for mineralization, and the sand body in this area The distribution is continuous and stable, and there are a small amount of thin mudstone interlayers, which are more conducive to the adsorption and mineralization of uranium;

Step 3.3 Determine the favorable oxidation sand rate of the prospecting target layer

The primary sedimentary sand bodies in the lower member of the Zhiluo Formation in the Binxian-Changwu area are gray, rich in carbon debris, coal lines and pyrite, and the gray sand bodies represent a reducing environment; in addition to the gray sand bodies, there are also purple-red, brown Red, yellow-brown, off-white, gray-green, variegated and other colors of sand bodies, among which the gray-green sand bodies are transformed from ancient oxidized sand bodies through oil and gas reduction, and the gray-white sand bodies are the hydrolysis of ancient oxidized sand bodies by acidic fluids In general, these colored sand bodies represent a certain degree of oxidation, and can be collectively classified as oxidized sand bodies. Finally, 152 data were used to compile the oxidation rate isomap. By analyzing the relationship between oxidized sand rate and uranium mineralization, it is established that the oxidized sand rate in the range of 0-50% is a favorable area for mineralization.

Step 4, comprehensive extraction of favorable mineralization information;

The favorable geological conditions extracted in the step 4.1 include the braided channel sedimentary subfacies, the distribution area of the stable slope zone of the target layer, the distribution area of the favorable sand body thickness of the target layer with a thickness of 20-50m, and the sand content rate of the target layer of 60%-90 % distribution area, the distribution area where the oxidized sand rate of the target layer is 0-50%.

The favorable prediction information extracted in the step 4.2 includes the uranium enrichment area of U/Th>0.32, the uranium enrichment area of active uranium Hui<-1, and the uranium depletion area of Hui>1. Translation of ore-controlling folds and faults. The U/Th>0.32 uranium enrichment area of the aerial radio is basically consistent with the uranium enrichment area of the active uranium Hui<-1, and is distributed in the syncline between the caprock anticlines near the east-west trending, and the fold ore control is the A significant sign of uranium mineralization in the region and a key ore-controlling factor; the unfavorable factor is that the uranium enrichment area is small and scattered, which is different from the multi-stage interlayer oxidation and fluid reformation of the uranium mineralization process analyzed in step 1.2. The results of the action are consistent. The uranium-depleted areas with Hui>1 are mainly distributed in the southwest and northwest, that is, the source direction of provenance and uranium source, which further proves that the judgment of the direction of erosion source area is correct.

Step 5, delineate favorable areas for mineralization, and comprehensively evaluate the metallogenic potential

In step 5, firstly, the favorable geological elements extracted in step 4.1 and the favorable prediction information extracted in step 4.2 are expressed in the form of layer layers in MapGIS, and then the uranium mineralization prospect area is jointly delineated by using MRAS software and geological professionals, Prepare forecast results graphs. Three prospective areas have been delineated, each of which is a superimposed area of multiple favorable geological elements and prediction information, and the prediction reliability is high.

Through the above 5 steps, it can be seen that the Binxian-Changwu area on the southern margin of the Ordos Basin has good uranium source conditions, with braided river facies and sand bodies of appropriate thickness rich in organic matter, and interlayer oxidation and oil and gas reduction developed in the later stage Transformation is beneficial to uranium mineralization. However, the nearly east-west trending fold belt inherited from the depositional period of the Zhiluo Formation separated the sand body and the interlayer oxidation zone, and the interlayer oxidation direction was superimposed in multiple stages and in different directions, resulting in a smaller uranium enrichment area in the later period. The ore-forming scale is limited, and the search for small and medium-sized uranium deposits should be the main focus, and the large ore bodies may still be in the north of the study area.

The present invention has been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above-mentioned embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. The content that is not described in detail in the present invention can adopt the prior art.

Claims (10)

1. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method, which is characterized in that this method comprises the following steps:

Step 1, the advantageous geologic setting of U metallogeny and ore-forming setting are determined；

Step 2, mine destination layer sedimentary subfacies or microfacies and spatial distribution are looked in determination；

Step 3, the identification and positioning of U metallogeny favorab1e sandbadies；

Step 4, it is extracted at mine advantageous information is comprehensive；

Step 5, delineation is at mine Favorable Areas, overall merit minerogenic potentiality；

The step 1 includes the following steps:

Destination layer containing mine and its superstratum are built inside the uranium source of step 1.1 analysis basin peripheral foot erosion source region and basin The uranium source made；

Step 1.2 determines the advantageous geological conditions of U metallogeny by tectonic sedimentary-Paleoclimatic Evolution comprehensive analysis；

In the step 1.1, uranium source analysis is the primary essential and requisite item of U metallogeny Potential Evaluation, should be analyzed Basin peripheral foot loses the uranium source of source region, analyzes the uranium source that destination layer containing mine and its superstratum are built inside basin again Condition；

The data of uranium source analysis can put data using measured data and boat, not only to analyze geologic body whether uranium-bearing (5 × 10^-6~10 × 10^-6) or Fu You (> 10 × 10^-6), more to analyze ancient uranium content (Gui), active uranium content (Hui) and uranium transport system Number (Bi) several key parameters, calculation formula such as formula (1) (2) shown in (3)；

Hui=Gui-Ui (2)

Bi=Hui/Gui (3)

Thi-actual measurement thorium content；Ui-actual measurement uranium content；- geologic element U/Th average value；

Wherein active uranium content (Hui) positive value shows that the point provides the ratio of mobile uranium for other locations, and negative value shows that the point connects By the enrichment of later period uranium；When uranium transport coefficient (Bi) is greater than 1, which has moving into and being enriched with for uranium, otherwise shows moving for uranium Out and dilution；

In the step 1.2, the Gu for looking for the mine destination layer deposition phase whether to have stable tectonic subsidence and relative humidity is analyzed Weather, it is ensured that destination layer has the sand body of steady and continuous to deposit, and sand thickness will have charcoal abundant in 20~60m, and in sand body Bits, seam organic matter, organic carbon content want > 0.2%；The deposition diagenesis later period of destination layer containing mine will have stable construction lifting effect Arid paleoclimate condition, destination layer buried depth, to be shallowly advisable, have local crop out in pelvic floor hernia at 1000 meters relatively, can Injection for uranium-bearing oxygenated water provides water inlet；There is certain effect of tilting during construction lifting, destination layer is caused to have surely Fixed slope belt development, ramp angles are generally less than 10 °, and slope length wants > 7km, can provide for the development of interlayer oxidized zone Sufficient action time；The U metallogeny later period should not have strong construction lifting effect, and ore body can be caused to be raised to earth's surface and degraded brokenly It is bad；The sandstone-type uranium deposit phase often matches with this area's sedimentary formation long term deletion phase and same period geologic climate for drought condition, This is an important Geologic Indicators for analyzing the U metallogeny phase.

2. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 1, it is characterised in that: the step Borehole data and well-log information are sufficiently collected in 2, in conjunction with surface occurence, establish the identification mark of sedimentary facies, parfacies and microfacies Will；By a plurality of drilling even well profile, the distribution mode of comparative analysis sedimentary facies is equivalent in sand thickness isopleth map and sand factor On the basis of figure establishment, further establishment deposits phasor；Sedimentary facies and relationship to uranium ore formation are studied, determines control mine sedimentary facies；Sandstone The best sedimentary facies of type uranium ore is braided stream and braided river delta, followed by meandering stream and meandering stream delta phase.

3. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 2, it is characterised in that: the step 3 include the following steps:

Mine destination layer favorab1e sandbadies thickness is looked in step 3.1 determination；

The advantageous sand factor of mine destination layer is looked in step 3.2 determination；

Step 3.3 determination looks for mine destination layer favorably to aoxidize sand coarse aggregate ratio.

4. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 3, it is characterised in that: step 3.1 exists On the basis of above-mentioned steps 2 work out sand thickness isopleth map, sand thickness and relationship to uranium ore formation are analyzed, it is thick to establish advantageous sand body Degree and spatial distribution.

5. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 4, which is characterized in that step 3.2 exists On the basis of above-mentioned steps 2 work out sand factor isopleth map, sand factor and relationship to uranium ore formation are analyzed, establishes advantageous sand factor and sky Between be distributed.

6. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 5, which is characterized in that the step Destination layer oxidation sand coarse aggregate ratio isopleth map is worked out in 3.3；Wherein 0 primary Grey Reduction ring is represented in grey detrital deposit construction Border represents primary Grey Reduction environment in red detrital deposit construction, and represents oil gas and be transformed into primary red build The reducing environment that grey is built；Analysis oxidation sand coarse aggregate ratio and relationship to uranium ore formation, establish advantageous oxidation sand coarse aggregate ratio and spatial distribution.

7. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 6, it is characterised in that: the step 4 include the following steps:

Step 4.1 extracts geological conditions to the advantageous information of U metallogeny；

Step 4.2 extract boat put, physical prospecting, change visit, in remote sensing data to Uranium Metallogenic Prognosis advantageous information.

8. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 7, it is characterised in that: the step The 4.1 advantageous geological conditions extracted include channel deposit parfacies, destination layer stabling slope band distributed area, destination layer favorab1e sandbadies thickness The distributed area of degree, the distributed area of the advantageous sand factor of destination layer, destination layer favorably aoxidize the distributed area of sand coarse aggregate ratio.

9. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 8, it is characterised in that: the step The 4.2 advantageous predictive information extracted include that boat puts uranium enrichment region, mobile uranium enrichment region and uranium loss area, ground radiological survey U Content exceptions area, control mine fold and the fracture of navigate magnetic and gravity joint interpretation, soil radon measurement exceptional value distributed area.

10. a kind of sandstone-type uranium mineralization with respect Comprehensive Assessment Technology method according to claim 9, it is characterised in that: the step Rapid 5 will lead to by ArcGIS software or MapGIS software realization at the conversion and extraction of the advantageous geological information of mine and component of forecast It crosses MRAS software and man-machine joint is drawn a circle to approve into mine Favorable Areas, and the Beneficial Ore-forming condition and unfavorable factor of analyzed area, it is final real Existing objective, accurately and efficiently evaluation region U metallogeny potentiality.