Identification method suitable for ancient granite uranium-rich ore

Abstract

The invention belongs to the technical field of geological exploration, and particularly relates to an ancient granite uranium-rich ore recognition method, which comprises the following steps of: 1, discussing an ancient granite uranium-rich ore metallogenic geological background; 2, analyzing ore control factors of different types of uranium-rich ores in the ancient granite body; and step 3, constructing an ancient granite uranium-rich ore identification mark. The method is efficient, rapid and high in operability, and a basis is provided for widening the prospecting direction of the granite type uranium mine.

Description

Technical Field

[0001] The invention belongs to the technical field of geological exploration, and in particular relates to a method for identifying uranium-rich ores in ancient granite bodies. Background Art

[0002] Since uranium-producing magmatic rocks are the products of mature crust, and different crustal units mature at different times, there is a certain regional specificity in their distribution in time. For example, the most important uranium-producing granite in South China developed in the Indosinian-Yanshanian period. The only exception is the Motianling granite body of the Xuefeng period in Guangxi, which produces the Xincun and Daliang uranium-rich deposits. Why does this ancient granite body produce such uranium-rich deposits, and how to identify such uranium-rich deposits is of great significance to broadening the prospecting direction of granite-type uranium deposits.

[0003] At present, my country's granite-type uranium deposits are mainly distributed in the Indosinian and Yanshanian granite areas where the Caledonian fold belt in South China is widely developed. There are also some uranium-rich granite-type uranium deposits in this type of granite areas, such as the Lanhe, Shituling, Menggongjie and other uranium-rich deposits. The current identification method is mainly aimed at the identification of uranium-rich deposits in this type of multi-period and multi-stage complex granite bodies. Summary of the invention

[0004] The purpose of the present invention is to provide a method for identifying rich uranium deposits in ancient granite bodies. The method is efficient, rapid and highly operable, and provides a basis for broadening the prospecting direction of granite-type uranium deposits.

[0005] A technical solution to achieve the purpose of the present invention is: a method for identifying uranium-rich ore in ancient granite, the method comprising:

[0006] Step 1: Explore the geological background of uranium-rich mineralization in ancient granite bodies;

[0007] Step 2: Analyze the ore-controlling factors of different types of uranium-rich deposits in ancient granite bodies;

[0008] Step 3: Construct identification marks for uranium-rich deposits in ancient granite bodies.

[0009] The step 1 comprises:

[0010] Step 1.1: Establish the magma evolution sequence of the ancient granite body by conducting petrology, mineralogy, chronology and geochemistry determination, and explore the source and evolution characteristics of its magma;

[0011] Step 1.2: Through remote sensing structural interpretation and field geological survey, the types and scale characteristics of regional fault structures are studied to identify the characteristics of regional ore-controlling fault structures;

[0012] Step 1.3: Summarize the regional geological evolution characteristics of ancient granite bodies through data collection and collation, field geological surveys and comprehensive mapping.

[0013] The regional geological evolution characteristics of the ancient granite body in step 1.3 include: formation and evolution characteristics of ancient granite, formation and evolution characteristics of important regional geological events, and formation and evolution characteristics of uranium mineralization.

[0014] The step 2 comprises:

[0015] Step 2.1: Classify typical uranium-rich deposits in ancient granite bodies according to their production environment, and use precise dating methods to determine the uranium mineralization age of ancient granite bodies;

[0016] Step 2.2, identify the characteristics of different types of uranium-rich ore-forming geological bodies, ore-forming structures, ore-forming structural surfaces, hydrothermal alteration, etc.;

[0017] Step 2.3: Analyze the key controlling factors of different types of uranium-rich ores.

[0018] The ore-controlling factors in step 2.3 include: structural ore-control, hydrothermal alteration ore-control, ore-control by different types of interfaces, and ore-control by late small rock bodies or vein rocks.

[0019] The step 3 is specifically as follows: through data collection and collation and secondary development, research on the physical, chemical and remote sensing characteristics of ancient granite bodies is carried out, aerial and ground radioactive data are summarized, the physical, chemical and remote sensing characteristics and their relationship with uranium mineralization are studied, and physical and chemical exploration signs for identifying uranium-rich deposits in ancient granite bodies are constructed; and geological signs for identifying uranium-rich deposits in ancient granite bodies are constructed by combining steps 1 and 2.

[0020] The geological signs include: the inner and outer contact zones of the granite body, especially the tongue-shaped depression zone at the edge of the rock body; the NNE-trending compression-torsion faults and the NWW-trending tension faults are important ore-controlling and ore-reservoir structures in the area, and the variation sites of the fault structures and the intersection sites of different faults are the most favorable sites for ore storage; areas with developed hydrothermal alteration such as dark gray and red microcrystalline quartz-chalcedony type silicification, illite hydromica, colloidal pyritization, vermicular chlorite, purple-black fluoritization, and hematite, especially colloidal pyritization and purple-black fluoritization are important prospecting signs for uranium-rich mineralization; uranium mineral points, uranium anomaly points or good uranium mineralization displays are developed on the surface.

[0021] The geophysical and geochemical exploration signs include: the surface γ anomaly is distributed in a band shape, which is controlled by the fault structure; the development of uranium and radon anomaly point belts in the water; the development of abnormal halos such as U, Pb, Cu, Zn, Y, and Be; the development of 210 Po is abnormal and distributed along the fault structure.

[0022] The beneficial technical effects of the present invention are:

[0023] 1. The present invention provides a method for identifying uranium-rich deposits in ancient granite bodies, establishes a method for identifying uranium-rich deposits in the Motianling area, submits favorable mineralization areas with uranium-rich deposit prospecting potential, and provides a basis for uranium-rich deposit prospecting and work deployment in the Motianling area.

[0024] 2. The present invention provides a method for identifying uranium-rich ores in ancient granite bodies, which can be used for geological exploration of hydrothermal uranium deposits in similar ancient granite bodies in my country, and has the characteristics of high efficiency and rapidity. The present invention is based on clear characteristics of magma, structure, hydrothermal fluid and uranium-rich mineralization, and has strong operability.

[0025] 3. The present invention provides a method for identifying uranium-rich ores in ancient granite bodies, which is suitable for enriching and improving the prospecting method of hydrothermal uranium ores, comprehensively carrying out comprehensive prediction and evaluation of uranium-rich ores in similar ancient granite bodies, and broadening the prospecting direction of granite-type uranium ores. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with embodiments.

[0027] The present invention provides a method for identifying uranium-rich ore in ancient granite, which specifically comprises the following steps:

[0028] Step 1: Explore the geological background of uranium-rich mineralization in ancient granite bodies;

[0029] Step 1.1: Establish the magma evolution sequence of the ancient granite massif by conducting petrological, mineralogical, chronological and geochemical measurements, and explore the source and evolutionary characteristics of the magma.

[0030] By conducting petrological observations on ancient granite bodies, the petrological characteristics of this type of granite are determined, and combined with zircon U-Pb dating, the diagenetic ages of different types of granite are determined, thus establishing the magmatic evolution sequence of the rock body; by conducting mineralogical and geochemical measurements, such as rock major and trace element determination, mineral micro-area isotope and trace element determination, etc., the source and evolutionary characteristics of the magma are explored.

[0031] Step 1.2: Through remote sensing structural interpretation and field geological surveys, study the types and scales of regional fault structures and identify the characteristics of regional ore-controlling fault structures.

[0032] By conducting remote sensing structural interpretation at small and medium scales (1:50,000 to 1:200,000), we can roughly interpret the fault structures of different directions and scales in the area; by conducting regional route geological surveys on key structures interpreted by remote sensing, we can find out the types and scales of fault structures; by collecting and collating data and studying typical mineral deposits, we can find out the style, mechanical properties, spatial occurrence and extension of the ore-controlling fault structures of typical mineral deposits.

[0033] Step 1.3: Through data collection and collation, field geological surveys and comprehensive mapping, summarize the regional geological evolution characteristics of ancient granite bodies, such as the formation and evolution characteristics of ancient granite, the formation and evolution characteristics of important regional geological events, and the formation and evolution characteristics of uranium mineralization.

[0034] Step 2: Analyze the ore-controlling factors of different types of uranium-rich deposits in ancient granite bodies;

[0035] Step 2.1: Classify typical uranium-rich deposits (points) in ancient granite bodies according to their production environment, and use precise dating methods to determine the uranium mineralization age of ancient granite bodies.

[0036] According to the production environment of the ore deposits, granite-type uranium deposits can be further divided into three subtypes: inner-zone type, outer-zone type and overlying basin type. The inner-zone type of granite can be further divided into several subtypes, such as silicification zone type, "intersection" type and cataclasite altered rock type. By conducting in situ U-Pb dating of pitchblende in different types of granite-type uranium deposits, the uranium mineralization age of the ancient granite body can be determined.

[0037] Step 2.2: Identify the characteristics of different types of uranium-rich mineralization geological bodies, mineralization structures, mineralization structural surfaces, hydrothermal alteration, etc.

[0038] The mineralization geological action of granite-type uranium deposits is mainly magmatic intrusion geological action, the geological body is an intrusive rock body, the mineralization structure is generally a regional fault structure and its secondary structure, the mineralization structural surface mainly includes the contact zone interface between the rock body and the stratum, the contact interface of granite of different periods, the secondary fault structure interface, the interface of the shattered altered rock belt and the tensile fracture zone in the sandwiched area of ​​the structural belt, the interface related to the intermediate-basic dyke, the favorable lithology redox interface, etc. The common hydrothermal alteration mainly includes silicification, hematization, hydromica, chloritization, potassium feldsparization, pyritization, carbonatization, fluoritization, etc. Through the study of the geological characteristics of different types of rich uranium deposits, the characteristics of different types of rich uranium deposits, mineralization geological bodies, mineralization structures, mineralization structural surfaces, hydrothermal alteration, etc. can be identified.

[0039] Step 2.3, analyze the key ore-controlling factors of different types of rich uranium ores. The ore-controlling factors of granite-type uranium ores are structural ore-controlling, hydrothermal alteration ore-controlling, different types of interface ore-controlling, late small rock bodies or vein rock ore-controlling, etc. Through the analysis of the ore-controlling factors of different types of rich uranium ores, the key ore-controlling factors are identified.

[0040] Step 3: construct identification marks of uranium-rich deposits in ancient granite bodies;

[0041] The identification marks of granite-type uranium deposits mainly include geological marks and geophysical and geochemical signs. Through data collection and secondary development, the physical, chemical and remote sensing characteristics of ancient granite bodies are studied, and the aerial and ground radioactive data are summarized to study their physical, chemical and remote sensing characteristics and their relationship with uranium mineralization, and to construct geophysical and geochemical signs for the identification of rich uranium deposits in ancient granite bodies; combined with steps 1 and 2, the geological signs for the identification of rich uranium deposits in ancient granite bodies are constructed.

[0042] Common geological signs include: inner and outer contact zones of granite body, especially the tongue-shaped depression zone at the edge of the rock body; NNE-trending compression-torsion faults and NWW-trending tension faults are important ore-controlling and ore-reservoir structures in the area, and the variation (turning, expansion) parts of the fault structures and the intersection of different faults are the most favorable parts for ore storage; areas with developed hydrothermal alteration such as dark gray and red microcrystalline quartz-chalcedony type silicification, illite hydromica, colloidal pyritization, vermicular chlorite, purple-black fluoritization, and hematite, especially colloidal pyritization and purple-black fluoritization are important prospecting signs for uranium-rich mineralization; uranium mineralization (ization) points, uranium anomaly points or better uranium mineralization displays are developed on the surface.

[0043] Common geophysical and geochemical exploration signs include: surface γ anomaly is distributed in a band, controlled by fault structure; abnormal uranium and radon in water are developed; abnormal halos of U, Pb, Cu, Zn, Y, Be, etc. are developed; 210 Po is abnormal and distributed along the fault structure.

[0044] Example 1

[0045] Taking the oldest Motianling granite in South China as an example, the present invention provides a method for identifying uranium-rich ore in ancient granite, which specifically includes the following steps:

[0046] Step 1: Explore the geological background of uranium-rich mineralization in the ancient granite body by collecting and arranging data, conducting field geological surveys and compiling comprehensive maps of the ancient granite body in Motianling.

[0047] Step 1.1: Establish the magma evolution sequence of the ancient granite body by conducting petrology, mineralogy, chronology and geochemistry determination, and explore the source and evolution characteristics of its magma

[0048] The internal phase, transition phase and marginal phase granites of the Motianling pluton were systematically sampled, and systematic LA-MC-ICP-MS zircon chronology, petrology, geochemistry and other determinations were carried out. It is believed that the Motianling pluton was formed at 770-850Ma, belonging to the Xuefeng period of the Neoproterozoic. The lithology of the Motianling pluton is composed of coarse-grained metaporphyritic, medium-grained porphyritic and fine-grained porphyritic biotite granites. The Motianling granite is a high-potassium calc-alkaline peraluminous granite, which is a silicon-rich, alkali-rich, aluminum-supersaturated S-type granite with potassium greater than sodium. The background value of uranium content in the pluton is as high as 22×10 -6It is an important uranium-producing rock body in South China, formed by the collision orogeny during the Jinning period.

[0049] Step 1.2: Through remote sensing structural interpretation and field geological survey, study the characteristics of regional fault structure types and scales, and focus on identifying the characteristics of regional ore-controlling fault structures.

[0050] Through remote sensing structural interpretation and field geological survey in Motianling area, the fault structures in Motianling area are divided into two groups according to the extension direction and mechanical properties of the faults: NNE compression-torsion and NWW tension-torsion. Both groups of faults are regional ore-controlling and ore-guiding faults; the NNE group of faults is the largest, represented by the Wuzishan (Fw), Gaowu (Fg), Zishanping (Fz), and Mamuling (Fm) faults; the NWW group of faults is the second largest, represented by the Shujiawan fault. Both NNE and NWW structures have a controlling effect on large-scale uranium mineralization in the area, especially the NNE structure. The uranium deposits and main mineral points in the area are distributed within 2.5km of the upper and lower plates of the regional Wuzishan (Fw), Gaowu (Fg) and Zishanping (Fm) faults.

[0051] Step 1.3: Summarize the regional geological evolution characteristics of ancient granite bodies through data collection and collation, field geological surveys and comprehensive mapping

[0052] Through data collection and collation, field geological survey and comprehensive mapping, the regional tectonic evolution of the Motianling area is divided into five stages: ① The formation and evolution stage of the basement rocks in the Neoproterozoic (770-850 Ma), which formed the basement rock structure in the Motianling area; ② The NW-trending thrust stage at the top of the Caledonian period (453-426 Ma), which formed the early SE-dipping ductile shear zone in the Motianling area; ③ The NE-trending normal ductile shear stage from the late Caledonian to the Hercynian period (426-295 Ma), which formed a widely distributed gneissic structure with a ductile shear zone pointing to the NWW; ④ The extensional tectonic stage from the late Yanshanian to the Himalayan period (85-47 Ma), which formed a ductile shear zone pointing to the N or NW, a brittle-ductile transition zone, tectonic breccia, fault gouge, etc.; ⑤ The tectonic uplift and erosion since the Himalayan period (47 Ma to present) formed a brittle thrust fault superimposed on the ductile shear deformation to the east.

[0053] Step 2: Dissect the typical uranium-rich deposits (points) in the ancient granite body of Motianling to identify the controlling factors of different types of uranium-rich deposits.

[0054] Step 2.1: Classify typical uranium-rich deposits (points) in ancient granite bodies according to the production environment of the deposits, and use precise dating methods to determine the uranium mineralization age of ancient granite bodies.

[0055] According to the production environment of the deposits, the uranium deposits in the Motianling rock body are mainly granite intrazonal uranium deposits, which are divided into two subtypes according to the ore-bearing lithology and production characteristics: siliceous vein type and cataclatic altered rock type. Taking the siliceous vein type Xincun uranium-rich deposit and the cataclatic altered rock type Daliang uranium-rich deposit as examples, petrographic observations of pitchblende and in-situ U-Pb dating were carried out, and the mineralization ages of the Xincun and Daliang uranium-rich deposits were accurately determined to be 50-57Ma and 401.5Ma, respectively, which are consistent with the late Yanshanian-Himalayan extensional tectonic stage and the late Caledonian-Hercynian NE-trending positive ductile shear stage.

[0056] Step 2.2: Identify the characteristics of different types of uranium-rich ore-forming geological bodies, ore-forming structures, ore-forming structural surfaces, hydrothermal alteration, etc.

[0057] Taking the siliceous vein type Xincun uranium-rich deposit and the cataclasite altered rock type Daliang uranium-rich deposit as examples, the characteristics of their ore-forming geological bodies, ore-forming structures, ore-forming structural surfaces, hydrothermal alteration, etc. were identified. The ore-forming geological body of the Xincun uranium-rich deposit is a coarse-grained porphyritic biotite granite with a flaky interior. The ore-forming structure is developed on the regional ore-controlling fault Wuzishan Fault F W The NE-trending (dipping NW) group faults represented by F1 in the hanging wall and F 10 、F 11 、F 12 The NE-trending (SE-dipping) group fault represented by the Daliang uranium-rich deposit is composed of ore-bearing faults and their secondary fracture surfaces, and the gneiss of the ductile shear zone. The hydrothermal alteration related to uranium mineralization is dark gray and red microcrystalline quartz-chalcedony type silicification, illite hydromicitization, colloidal pyritization, purple-black fluorite, and hematite. The uranium minerals are mainly pitchblende, and the uranium ore types are uranium-silicification type and uranium-fluorite type. The mineralized geological body of the Daliang uranium-rich deposit is the transitional fine-grained and medium-grained granite at the edge of the rock mass and the quartz siltstone of the ninth group of the Sibao Group in the outer belt. The mineralization structure is F1, F2, F3, F4, F5, F6, F7, F8. 12 NE-trending faults represented by F 31 、F 32 The NW-trending fault is represented by , the mineralization structure surface is the ore-bearing fault and its secondary fissure joints or cleavage, as well as the internal and external contact zones of the rock body. The hydrothermal alteration related to uranium mineralization is vermicular chlorite, colloidal pyritization, hematite, sericite and silicification, etc. The uranium mineral is mainly pitchblende, and the uranium ore type is uranium-chlorite (pyrite) type.

[0058] Step 2.3: Analyze the key ore-controlling factors of different types of uranium-rich ores

[0059] Taking the siliceous vein-type Xincun uranium-rich deposit and the cataclasite-altered rock-type Daliang uranium-rich deposit as examples, the control of faults, alteration and lithology on uranium mineralization was analyzed, and it is believed that fault structure is the most critical ore-controlling factor in the Motianling area.

[0060] Control of fault structure on uranium mineralization. According to the nature of the ore-bearing faults, the ore-bearing faults in the Motianling area can be roughly divided into four groups, namely NE-trending (dipping NW) ore-bearing faults, NE-trending (dipping SE) ore-bearing faults, NW-trending (dipping SW) ore-bearing faults and EW-trending (dipping N) ore-bearing faults. Among them, the NE-trending (dipping NW) ore-bearing faults and the NE-trending (dipping SE) ore-bearing faults are the most important directions of ore-bearing faults in the Motianling area, representing two mineralization events in the Motianling area respectively. Among them, the NE-trending (dipping SE) ore-bearing faults represent the uranium mineralization event formed in the Hercynian period in the Motianling area, represented by the Daliang deposit; the NE-trending (dipping NW) ore-bearing faults represent the uranium mineralization event in the late Yanshanian-Himalayan period, represented by the Xincun deposit.

[0061] Control of hydrothermal alteration on uranium mineralization. Hydrothermal activities closely related to uranium mineralization are mainly divided into two phases and two categories. The first phase is the regional metamorphic-tectonic hydrothermal activity from the late Caledonian to the Hercynian period. This period is characterized by the hydrothermal filling and metasomatism of hematite-chlorite caused by regional metamorphic alkali metasomatism and greisenization. It is mainly distributed in Daliang, Chashan, Gaoti, Wuhua and other areas, and mainly forms uranium-chlorite type uranium mineralization, represented by the Daliang deposit; the first phase is the siliceous hydrothermal filling and metasomatism that occurred during the Yanshanian-Himalayan period accompanied by extensional tectonic action. This type is a common and intense hydrothermal activity in the region, mainly forming uranium-silicification belt type uranium mineralization, represented by the Xincun deposit.

[0062] Lithology controls uranium mineralization. Uranium mineralization and anomalies are mainly found in the transition zone between medium and coarse-grained porphyritic biotite granite. This type of lithology has a porphyritic structure and gneissic structure, which is easy to be structurally broken and ore-forming fluid penetrated and altered, which is conducive to the precipitation and aggregation of uranium.

[0063] Step 3: Study the physical and chemical characteristics of ancient granite bodies and their relationship with uranium mineralization, and combine steps 1 and 2 to construct identification marks for uranium-rich deposits in ancient granite bodies.

[0064] By carrying out remote sensing structural interpretation, field geological surveys, and dissection of typical uranium deposits (points), combined with previous research results such as geophysics, chemistry, and remote sensing, a comprehensive prospecting and identification mark for rich uranium mines in the Motianling area was constructed.

[0065] Geological signs: ① The inner and outer contact zones of the Motianling granite, especially the tongue-shaped depression zone at the edge of the rock mass; ② The NNE-trending Wuzhishan, Gaowu, Zishanping and Mamuling compression-torsion faults and the NWW-trending tensional faults are important ore-controlling and ore-reservoir structures in the area. The variation (turning, expansion) parts of the fault structures and the intersection of different faults are the most favorable locations for ore storage; ③ The areas with developed hydrothermal alteration such as dark gray and red microcrystalline quartz-chalcedony type silicification, illite hydromica, colloidal pyritization, vermicular chlorite, purple-black fluoritization, and hematite, especially the colloidal pyritization and purple-black fluoritization are important prospecting signs for uranium-rich mineralization; ④ The surface is developed with uranium mineralization points, uranium anomaly points or good uranium mineralization displays.

[0066] Geophysical and geochemical exploration signs: ① Surface γ anomaly is distributed in a band, controlled by fault structure; ② Development of uranium and radon anomaly zones in water; ③ Development of abnormal halos of U, Pb, Cu, Zn, Y, Be, etc.; ④ Development of 210 Po is abnormal and distributed along the fault structure.

[0067] The present invention is described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

1. A method for identifying uranium-rich ores in ancient granite, characterized in that: The method comprises: Step 1: Explore the geological background of uranium-rich mineralization in ancient granite bodies; Step 2: Analyze the ore-controlling factors of different types of uranium-rich deposits in ancient granite bodies; Step 3: Construct identification marks for uranium-rich deposits in ancient granite bodies.

2. The method for identifying uranium-rich ores in ancient granite according to claim 1, characterized in that: The step 1 comprises: Step 1.1: Establish the magma evolution sequence of the ancient granite body by conducting petrology, mineralogy, chronology and geochemistry determination, and explore the source and evolution characteristics of its magma; Step 1.2: Through remote sensing structural interpretation and field geological survey, the types and scale characteristics of regional fault structures are studied to identify the characteristics of regional ore-controlling fault structures; Step 1.3: Summarize the regional geological evolution characteristics of ancient granite bodies through data collection and collation, field geological surveys and comprehensive mapping.

3. The method for identifying uranium-rich ores in ancient granite according to claim 2, characterized in that: The regional geological evolution characteristics of the ancient granite body in step 1.3 include: formation and evolution characteristics of ancient granite, formation and evolution characteristics of important regional geological events, and formation and evolution characteristics of uranium mineralization.

4. The method for identifying uranium-rich ores in ancient granite according to claim 1, characterized in that: The step 2 comprises: Step 2.1: Classify typical uranium-rich deposits in ancient granite bodies according to their production environment, and use precise dating methods to determine the uranium mineralization age of ancient granite bodies; Step 2.2, identify the characteristics of different types of uranium-rich ore-forming geological bodies, ore-forming structures, ore-forming structural surfaces, hydrothermal alteration, etc.; Step 2.3: Analyze the key controlling factors of different types of uranium-rich ores.

5. The method for identifying uranium-rich ores in ancient granite according to claim 4, characterized in that: The ore-controlling factors in step 2.3 include: structural ore-control, hydrothermal alteration ore-control, ore-control by different types of interfaces, and ore-control by late small rock bodies or vein rocks.

6. The method for identifying uranium-rich ores in ancient granite according to claim 1, characterized in that: The step 3 is specifically as follows: through data collection and collation and secondary development, research on the physical, chemical and remote sensing characteristics of ancient granite bodies is carried out, aerial and ground radioactive data are summarized, the physical, chemical and remote sensing characteristics and their relationship with uranium mineralization are studied, and physical and chemical exploration signs for identifying uranium-rich deposits in ancient granite bodies are constructed; and geological signs for identifying uranium-rich deposits in ancient granite bodies are constructed by combining steps 1 and 2.

7. The method for identifying uranium-rich ores in ancient granite according to claim 6, characterized in that: The geological signs include: the inner and outer contact zones of the granite body, especially the tongue-shaped depression zone at the edge of the rock body; the NNE-trending compression-torsion faults and the NWW-trending tension faults are important ore-controlling and ore-reservoir structures in the area, and the variation sites of the fault structures and the intersection sites of different faults are the most favorable sites for ore storage; areas with developed hydrothermal alteration such as dark gray and red microcrystalline quartz-chalcedony type silicification, illite hydromica, colloidal pyritization, vermicular chlorite, purple-black fluoritization, and hematite, especially colloidal pyritization and purple-black fluoritization are important prospecting signs for uranium-rich mineralization; uranium mineral points, uranium anomaly points or good uranium mineralization displays are developed on the surface.

8. The method for identifying uranium-rich ores in ancient granite according to claim 6, characterized in that: The geophysical and geochemical exploration signs include: the surface γ anomaly is distributed in a band shape, which is controlled by the fault structure; the development of uranium and radon anomaly point belts in the water; the development of abnormal halos such as U, Pb, Cu, Zn, Y, and Be; the development of 210 Po is abnormal and distributed along the fault structure.