Method for evaluating the effect of medium-basic rock intrusion on uranium mineralization in sandstone type uranium deposit

Abstract

The present application belongs to the technical field of uranium mine, and particularly relates to a method for evaluating the effect of intermediate-basic rock intrusion reformation on uranium mineralization in sandstone type uranium mine, which comprises the following steps: step one, data collection; step two, field core observation and sample collection; step three, evaluation of the space-time relationship between intermediate-basic rock intrusion reformation and uranium mineralization; step four, evaluation of the influence of intermediate-basic rock intrusion reformation on the physical property of ore-bearing layer; step five, evaluation of the influence of intermediate-basic rock intrusion reformation on groundwater migration and driving mechanism; step six, evaluation of the influence of intermediate-basic rock intrusion reformation on uranium mineralization; and step seven, comprehensive analysis and evaluation of the uranium mineralization effect of intermediate-basic rock intrusion reformation in sandstone type uranium mine. The method comprehensively evaluates the influence of intermediate-basic rock intrusion reformation on the formation and preservation of uranium mine, identifies the uranium mineralization effect of intermediate-basic rock intrusion reformation in sandstone type uranium mine, and establishes a sandstone uranium mineralization pattern diagram of intermediate-basic rock intrusion reformation.

Description

Technical Field

[0001] This invention belongs to the field of uranium mining technology, specifically relating to a method for evaluating the mineralization effect of uranium modified by intrusion of basic rocks in sandstone-type uranium deposits. Background Technology

[0002] In recent years, with the deepening of exploration and research on sandstone-type uranium deposits in China, more and more uranium geologists have discovered that Mesozoic-Cenozoic intermediate-basic volcanic rocks are locally developed in the interior or margins of uranium-producing basins in the central and eastern parts of China (Ordos, Erenhot, Songliao and Bayingobi). The sandstone-type uranium deposits developed around these deposits show significant differences from typical interbedded oxidation zone sandstone-type uranium deposits (southern margin of the Ili Basin) in terms of geochemical zoning characteristics, uranium mineralization characteristics, and ore body morphology. The sandstone-type uranium deposits in the southern margin of the Songliao Basin are particularly typical, with diabase caps (veins) widely developed in the area. Their formation age (45.8~53.0 Ma) is well correlated with the main mineralization age of sandstone-type uranium deposits (28.0~53.0 Ma). Diabase veins cutting through the ore-bearing strata and uranium ore bodies occurring nearby are also visible, indicating a certain intrinsic relationship between diabase intrusion and alteration and uranium mineralization.

[0003] However, current research focuses on the water-retaining effect of diabase itself, the provision of favorable mineralization environment, and the superimposed alteration effect on uranium deposits. It neglects the impact of diabase intrusion accompanied by large-scale CO2 charging, groundwater dynamic conditions, and changes in sandstone properties on uranium mineralization. As a result, the intrinsic relationship between intermediate-basic rock intrusion and uranium mineralization remains unclear. Specifically, it is unclear whether intermediate-basic rock intrusion participates in uranium mineralization, whether it can provide uranium sources for uranium mineralization, in what way it participates in uranium mineralization, how much it contributes to uranium mineralization, and how it affects the location of uranium ore bodies.

[0004] Furthermore, the current exploration and prospecting of sandstone-type uranium deposits is influenced by the prospecting approach for sandstone-type uranium deposits with interlayer oxidation zones, which can easily lead to the omission of uranium ore bodies that have undergone strong thermal alteration or are controlled by thermal alteration during the exploration process. Summary of the Invention

[0005] The purpose of this invention is to provide a method for evaluating the uranium mineralization effect of intrusion and modification by intermediate-basic rocks in sandstone-type uranium deposits. This method evaluates the impact of intrusion and modification by intermediate-basic rocks on the formation and preservation of sandstone-type uranium deposits, clarifies the uranium mineralization effect of intrusion and modification by intermediate-basic rocks in sandstone-type uranium deposits, establishes a mineralization model diagram of sandstone uranium mineralization by intrusion and modification by intermediate-basic rocks, proposes subsequent prospecting ideas and directions, and prevents the omission of uranium ore bodies that have been strongly thermally modified or controlled by thermal modification during subsequent exploration. This provides new clues for expanding the prospecting space and direction of sandstone-type uranium deposits in areas with intrusion and modification by intermediate-basic rocks.

[0006] Technical solution to achieve the purpose of this invention:

[0007] A method for evaluating the uranium mineralization effect of intrusions into basic rocks in sandstone-type uranium deposits, the method comprising:

[0008] Step 1: Data Collection;

[0009] Step Two: Field Core Observation and Sample Collection;

[0010] Step 3: Evaluate the spatiotemporal relationship between intermediate-basic rock intrusion and alteration and uranium mineralization;

[0011] Step 4: Evaluate the impact of intermediate-basic rock intrusion and alteration on the physical properties of the ore-bearing strata;

[0012] Step 5: Evaluate the impact of intermediate-basic rock intrusion and alteration on groundwater migration and its driving mechanism;

[0013] Step Six: Evaluate the impact of intermediate-basic rock intrusion and alteration on uranium mineralization;

[0014] Step 7: Comprehensive analysis and evaluation of the uranium mineralization effect of intrusion and alteration by basic rocks in sandstone-type uranium deposits.

[0015] The data collected in step one includes: borehole data, seismic data, and known uranium mineralization characteristics data for the study area.

[0016] The samples collected in step two include: intermediate-basic rocks, mineral-bearing sandstone, thermally modified sandstone, and unmodified sandstone samples.

[0017] The third step specifically involves: drawing a spatial distribution map of intermediate-basic rocks and ore bodies, determining the whole-rock Ar-Ar age of intermediate-basic rocks, and investigating the spatiotemporal coupling between intermediate-basic rocks and uranium mineralization in the study area.

[0018] Step four specifically involves studying the porosity and permeability of heated and unheated sandstone samples. When the porosity and permeability of the heated sandstone are both greater than those of the unheated sandstone, it indicates that the intrusion and modification process of intermediate-basic rocks can improve the physical properties of the sandstone, which is beneficial to uranium mineralization in sandstone; conversely, it cannot improve the physical properties of the sandstone, which is detrimental to uranium mineralization in sandstone.

[0019] Step five specifically involves: drawing a characteristic map of the distribution of oxidation zones between sandstone-type uranium deposits in the study area; using the planar distribution direction, size, and oxidation thickness of the ore-bearing layers in the oxidation zone profile to determine the direction and path of paleogroundwater migration; and determining the approximate locations of paleogroundwater recharge and discharge areas and the paleogroundwater dynamic system.

[0020] Step five also includes: for areas that have been intruded and altered by intermediate-basic rocks, determining whether the changes in groundwater transport patterns caused by local thermal anomalies are favorable for sandstone uranium mineralization.

[0021] Step six includes: determining whether the intrusion and alteration of intermediate-basic rocks can provide uranium sources for uranium mineralization, whether they can provide favorable conditions for uranium migration, and whether they can provide a favorable environment for uranium enrichment and precipitation, and evaluating the impact of the intrusion and alteration of intermediate-basic rocks on uranium mineralization.

[0022] The question of whether the intermediate-basic rock intrusion can provide a uranium source for uranium mineralization is specifically addressed by conducting comparative studies on the U and Th element content of intermediate-basic rocks, thermally modified sandstone, and unmodified sandstone samples to evaluate whether intermediate-basic rock intrusions can provide a uranium source for sandstone uranium mineralization.

[0023] Whether the intrusion and modification of intermediate-basic rocks can provide favorable conditions for uranium migration is specifically determined by: conducting homogenization temperature and laser Raman studies on the primary inclusions of hydrothermal alteration minerals in the thermally modified sandstone to identify the hydrothermal properties and composition related to the intrusion of intermediate-basic rocks.

[0024] Step seven specifically involves the following: If the intermediate-basic rock intrusion and uranium mineralization in Step three are inconsistent in both space and time, then the intermediate-basic rock intrusion is considered to have little relationship with sandstone uranium mineralization; if the intermediate-basic rock intrusion and uranium mineralization in Step three have a good spatial relationship but inconsistent temporal relationship, then the influence of faults related to the intermediate-basic rock intrusion on sandstone uranium mineralization should be considered; if the intermediate-basic rock intrusion and uranium mineralization in Step three have a close spatiotemporal relationship, indicating that there is a certain intrinsic genetic connection between the intermediate-basic rock intrusion and sandstone uranium mineralization, then a comprehensive analysis of the steps is required. Steps four through six focus on the impact of intermediate-basic rock intrusion on the physical properties of ore-bearing strata, groundwater migration and driving mechanisms, and on uranium migration and enrichment in sandstone uranium mineralization. The study aims to clarify the uranium mineralization effect of intermediate-basic rock intrusion on sandstone-type uranium deposits and comprehensively evaluate its influence on the formation and preservation of sandstone-type uranium deposits. Based on the alteration of the original gravity-driven mechanism by intermediate-basic rock intrusion, and taking the groundwater-thermal driving mechanism as a starting point, a thermally driven sandstone uranium mineralization model diagram of intermediate-basic rock intrusion is established, combining groundwater migration paths and recharge-pathway-drainage systems.

[0025] The beneficial technical effects of this invention are as follows:

[0026] This invention provides a method for evaluating the mineralization effect of intermediate-basic rock intrusions on sandstone-type uranium deposits. It not only elucidates the superimposed mineralization process of hydrothermal alteration of the original sandstone-type uranium deposits by intermediate-basic rock intrusions from the perspective of uranium activation (uranium source)-migration-precipitation, but also controls the formation of uranium ore bodies that are strongly or controlled by thermal alteration. Furthermore, it comprehensively clarifies the influence of intermediate-basic rock intrusions accompanied by large-scale CO2 charging, groundwater dynamic conditions, and changes in sandstone physical properties on sandstone uranium mineralization, emphasizing that intermediate-basic rock intrusions can alter the mode and velocity of groundwater migration. The formation and expansion of the original interlayer oxidation zone controlled the formation of sandstone uranium mineralization. This study comprehensively evaluated the impact of intermediate-basic rock intrusion on the formation and preservation of uranium deposits. Furthermore, it established a sandstone uranium mineralization model for intermediate-basic rock intrusion, pointing out that prospecting for sandstone-type uranium deposits in intermediate-basic rock intrusion zones should not only focus on interlayer oxidized sandstone-type uranium deposits but also prevent the omission of uranium ore bodies that have undergone strong thermal alteration or are controlled by thermal alteration during exploration. This provides new clues for expanding the prospecting types and directions for sandstone-type uranium deposits in intermediate-basic rock intrusion zones. Attached Figure Description

[0027] Figure 1 A flowchart of a method for evaluating the uranium mineralization effect of intrusion and alteration of intermediate-basic rocks in sandstone-type uranium deposits provided by the present invention;

[0028] Figure 2 This invention provides a spatial distribution map of sandstone-type uranium deposits and diabase in the southern Songliao Basin.

[0029] Figure 2 a is a planar characteristic map of the distribution of sandstone-type uranium ore bodies and diabase in the study area;

[0030] Figure 2 b is a map showing the location of diabase intrusions in a single well in the study area and their distribution characteristics with uranium ore bodies;

[0031] Figure 2 c is a diagram showing the location and spatial distribution characteristics of diabase intrusions in the seismic profile;

[0032] Figure 2 In a, 1-Taikang Formation; 2-Nenjiang Formation; 3-Yaojia Formation; 4-Diabase; 5-Ancient uplift granite; 6-Fault; 7-Mining area; 8-Place name; 9-Uranium deposit; 10-Tectonic window; 11-Unconformity surface;

[0033] Figure 3 The present invention provides a planar (a) and cross-sectional (be) distribution characteristic of the oxidation zone of the sandstone-type uranium deposit in the southern margin of the Songliao Basin, as well as a groundwater dynamic system diagram.

[0034] Figure 3 a is a diagram showing the planar distribution characteristics of the interlayer oxidation zone and the groundwater dynamic system of the uranium deposits in the study area;

[0035] Figure 3 b is a diagram showing the distribution characteristics of the interlayer oxidation zone and the regional groundwater dynamic system in the AB section (NE direction) of the study area;

[0036] Figure 3 c shows the distribution characteristics of the interlayer oxidation zone and the regional and local groundwater dynamic system in the CD section (NE direction) of the study area;

[0037] Figure 3 d shows the distribution characteristics of the interlayer oxidation zone and the regional and local groundwater dynamic system in the EF profile (NE direction) of the study area;

[0038] Figure 3 e represents the distribution characteristics of the interlayer oxidation zone and the regional and local groundwater dynamic system in the GH profile (NW direction) of the study area;

[0039] Figure 3 In the diagram e, 1-primary oxidation zone; 2-interlayer oxidation zone; 3-oxidation-reduction transition zone + reduction zone; 4-ancient uplift granite; 5-Carboniferous-Permian basement; 6-Lower Cretaceous Fuxin Formation; 7-oxidation front; 8-regional groundwater migration direction; 9-local groundwater migration direction; 10-fault; 11-section location; 12-tectonic window; 13-uranium deposit; 14-uranium deposit location; 15-stratigraphic boundary; 16-uranium ore body; 17-diabase; 18-mudstone lens; 19-drill hole; 20-place name;

[0040] Figure 4 This is a diagram illustrating the uranium mineralization model of diabase intrusion and alteration in sandstone-type uranium deposits on the southern margin of the Songliao Basin, provided by this invention.

[0041] Figure 4 In the middle, 1-primary oxidation zone; 2-interlayer oxidation zone; 3-upper interlayer oxidation zone; 4-lower interlayer oxidation zone; 5-oxidation-reduction transition zone + reduction zone; 6-Nenjiang Formation; 7-Qingshankou Formation; 8-Fuxin Formation; 9-Carboniferous-Permian; 10-ancient uplift granite; 11-oxidation front; 12-regional groundwater migration direction; 13-local groundwater migration direction; 14-fault; 15-tectonic window; 16-uranium deposit; 17-stratigraphic boundary; 18-uranium ore body; 19-diabase. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0043] like Figure 1 As shown, the present invention provides a method for evaluating the mineralization effect of intrusive-basic rocks in sandstone-type uranium deposits, which specifically includes the following steps:

[0044] Step 1: Data collection.

[0045] The collected data includes extensive borehole data, seismic data, and known uranium mineralization characteristics data for the study area, and a preliminary summary of the spatial distribution characteristics of intermediate-basic rock intrusions.

[0046] Step 2: Field core observation and sample collection.

[0047] Based on the data collected in step one, through field core observation, boreholes that were intruded and modified by intermediate-basic rocks were selected to carry out corresponding sample collection work. The collected samples included intermediate-basic rocks, mineral-bearing sandstone, thermally modified sandstone and unmodified sandstone samples.

[0048] Step 3: Evaluate the spatiotemporal relationship between intermediate-basic rock intrusion and alteration and uranium mineralization.

[0049] Based on the borehole and seismic data collected in Step 1 and the intermediate-basic rock samples collected in Step 2, a spatial distribution map of intermediate-basic rocks and ore bodies is drawn using a large amount of borehole data, including a series of planar and cross-sectional distribution maps. Then, whole-rock Ar-Ar age determination of intermediate-basic rocks is carried out. Combined with the existing uranium mineralization ages, the spatiotemporal coupling between intermediate-basic rocks and uranium mineralization in the study area is investigated. If the spatial distribution of intermediate-basic rocks and uranium ore bodies is close and the temporal coupling is good, the subsequent evaluation steps can be carried out. Otherwise, the process proceeds directly to the comprehensive analysis stage in Step 7.

[0050] Step 4: Evaluate the impact of intermediate-basic rock intrusion and alteration on the physical properties of the ore-bearing strata.

[0051] Based on the thermally modified and unmodified sandstone samples collected in step two, a comparative study of physical property parameters was conducted. These parameters included porosity and permeability. When the porosity and permeability of the thermally modified sandstone were both greater than those of the unmodified sandstone, it indicated that the intrusion and modification process of intermediate-basic rocks (diabase) could improve the physical properties of the sandstone, which was beneficial to uranium mineralization in sandstone. Conversely, it could not improve the physical properties of the sandstone, which was detrimental to uranium mineralization in sandstone. This provides support for the comprehensive evaluation of the uranium mineralization effect of intermediate-basic rock intrusion and modification in sandstone-type uranium deposits in step seven.

[0052] Step 5: Evaluate the impact of intermediate-basic rock intrusion and alteration on groundwater migration and its driving mechanism.

[0053] Based on the borehole data collected in Step 1, a map showing the distribution characteristics of the oxidation zone between sandstone-type uranium deposits in the study area was drawn, including planar and cross-sectional distribution maps. The formation of the oxidation zone is a complete process in which oxygen-rich groundwater infiltrates from the recharge area, flows through the ore-bearing layer, and undergoes oxidation and alteration with the ore-bearing sandstone, before being discharged into the discharge area. Typically, groundwater near the recharge area is rich in oxygen and exhibits stronger oxidation, resulting in relatively large oxidation zones, both in planar distribution and cross-sectional thickness of the ore-bearing layer. Conversely, near the discharge area, the oxygen in the groundwater is depleted, leading to weaker oxidation or no oxidation zone formation. Therefore, the planar distribution direction, size, and cross-sectional thickness of the oxidation zone can be used to roughly determine the direction and path of paleogroundwater migration, and to identify the approximate locations of the paleogroundwater recharge and discharge areas, as well as the paleogroundwater dynamic system. Furthermore, current studies on sandstone uranium mineralization often emphasize the control of gravity-driven interlayer infiltration-runoff-discharge of oxygenated groundwater, neglecting the fact that magmatic intrusion thermal anomalies can easily alter groundwater transport mechanisms. Magmatic intrusion thermal anomalies causing groundwater to migrate via convection is a crucial mode of groundwater transport in geothermal systems. Therefore, in areas altered by intermediate-basic rock intrusions, localized thermal anomalies can cause oxygenated groundwater to migrate via thermally driven convection, altering the existing gravity-driven transport pattern. This results in inconsistencies between the formed oxidation zones and uranium ore bodies and typical interlayer oxidation zone uranium ore bodies (sandstone-type uranium deposits in the Ili and Turpan-Hami basins). This provides support for the comprehensive evaluation of the uranium mineralization effect of intermediate-basic rock intrusion alteration in sandstone-type uranium deposits in step seven.

[0054] Step Six: Evaluate the impact of intermediate-basic rock intrusion and alteration on uranium mineralization.

[0055] Guided by the uranium mineralization process of uranium activation (uranium source) - migration - enrichment and precipitation, this study aims to determine whether the intrusion and alteration of intermediate-basic rocks can provide uranium sources for uranium mineralization, whether they can provide favorable conditions for uranium migration, and whether they can provide a favorable environment for uranium enrichment and precipitation. This will provide support for the comprehensive evaluation of the uranium mineralization effect of intrusion and alteration of intermediate-basic rocks in sandstone-type uranium deposits in step seven.

[0056] Whether intrusive alteration of intermediate-basic rocks can provide uranium sources for uranium mineralization is evaluated through comparative analysis of U and Th elemental contents in intermediate-basic rocks, thermally altered sandstone, and unthermally altered sandstone samples. When the U content and U / Th ratio do not vary significantly among different intermediate-basic rock samples, and when the U content and U / Th ratio do not vary significantly between thermally altered and unthermally altered sandstone samples, it indicates that intrusive alteration of intermediate-basic rocks cannot provide uranium sources for uranium mineralization. Conversely, when the U content and U / Th ratio vary significantly among different intermediate-basic rock samples, and the U content and U / Th ratio of thermally altered sandstone are greater than or significantly greater than those of unthermally altered sandstone samples, it indicates that intrusive alteration of intermediate-basic rocks cannot provide uranium sources for uranium mineralization. This indicates that the intrusion of intermediate-basic rocks can provide some uranium source for sandstone uranium mineralization. When the U content and U / Th ratio in different intermediate-basic rock samples do not vary much, but the U content and U / Th ratio in thermally modified sandstone are greater than or much greater than those in unmodified sandstone samples, it indicates that the intermediate-basic rocks themselves cannot provide uranium source for sandstone uranium mineralization, but the thermal fluids caused by the intrusion process of intermediate-basic rocks can extract uranium from the strata and provide some uranium source for sandstone uranium mineralization.

[0057] Whether the intrusion and alteration of intermediate-basic rocks can provide favorable conditions and environment for uranium migration was investigated by studying the homogenization temperature of primary inclusions in hydrothermal alteration minerals and using laser Raman spectroscopy on thermally altered sandstones to clarify the hydrothermal properties related to the intrusion of intermediate-basic rocks. Eh-pH-T ) and composition. Currently, the high CO2 content in groundwater in sandstone-type uranium deposits determines that uranium mainly migrates as uranyl carbonate complexes, but temperature ( T pH () pH Factors such as uranium concentration, CO2 content, and ionic strength all affect the type and proportion of uranium carbonate complexes, thus influencing the uranium migration, enrichment, and precipitation process in sandstone-type uranium deposits. For example, Ca... 2+ In CO2-rich fluids with high concentrations, U(VI) migrates in the form of a stable Ca-U(VI)-CO3 ternary complex, which is conducive to the long-term stable migration and enrichment of U(VI) into ore-forming fluids; the stronger the alkalinity (pH<10), the higher the CO3 content in the solution. 2-The higher the proportion of uranium, the better the extraction of uranium by the fluid and the oxidation of uranium minerals, and the easier it is to form stable uranyl carbonate complexes. This is conducive to the long-term stable migration and enrichment of U(VI) in the ore-forming fluid into ore. The increase in temperature can increase the stability constant of the uranyl carbonate complexation reaction, making the uranyl carbonate complex more stable. This is also conducive to the long-term stable migration and enrichment of U(VI) in the ore-forming fluid into ore. However, the temperature should not be too high (>250℃). Too high a temperature can easily reduce the solubility of CO2, inhibit the formation of highly coordinated uranyl carbonate complexes, etc., which is not conducive to the long-term stable migration and enrichment of U(VI) in the ore-forming fluid into ore. A sudden decrease in pressure will cause CO2 gas to escape from the fluid, causing the uranyl carbonate complex to decompose and form a uranium ore body.

[0058] Step 7: Comprehensive analysis and evaluation of the uranium mineralization effect of intrusion and alteration by basic rocks in sandstone-type uranium deposits.

[0059] In step three, the spatiotemporal relationship between intermediate-basic rock intrusion and uranium mineralization is clarified. If the spatial and temporal relationships between intermediate-basic rock intrusion and uranium mineralization are inconsistent, it is considered that the relationship between intermediate-basic rock intrusion and sandstone uranium mineralization is not significant. If intermediate-basic rock intrusion and uranium mineralization have a good spatial relationship but inconsistent temporal relationships, the influence of faults related to intermediate-basic rock intrusion on sandstone uranium mineralization should be considered. If intermediate-basic rock intrusion and uranium mineralization have a close spatiotemporal relationship, it indicates that there is a certain intrinsic genetic connection between intermediate-basic rock intrusion and sandstone uranium mineralization. In this case, it is necessary to comprehensively analyze the impact of intermediate-basic rock intrusion modification on sandstone physical properties, groundwater migration and driving forces, and uranium migration and enrichment in sandstone uranium mineralization in steps four to six, to investigate the uranium mineralization effect of intermediate-basic rock intrusion modification in sandstone-type uranium deposits, and to comprehensively evaluate the impact of intermediate-basic rock intrusion modification on the formation and preservation of sandstone-type uranium deposits. Based on the alteration of the original gravity-driven mechanism by intermediate-basic rock intrusion, this paper takes the groundwater-thermal driven mechanism as the starting point, combines the groundwater migration path and the recharge-drainage system, establishes a thermally driven sandstone uranium mineralization model diagram of intermediate-basic rock intrusion, and proposes subsequent exploration ideas and directions for sandstone-type uranium deposits in the intermediate-basic rock intrusion-modified areas.

[0060] Example 1

[0061] Taking the sandstone-type uranium deposit in the southern margin of the Songliao Basin as an example, this invention provides a method for evaluating the mineralization effect of intermediate-basic rock intrusion in sandstone-type uranium deposits, specifically including the following steps:

[0062] Step 1: Data Collection;

[0063] The collected data includes extensive borehole data, seismic data, and known uranium mineralization characteristics from sandstone-type uranium deposits on the southern margin of the Songliao Basin. For example, industrial uranium mineralization in the southern Songliao Basin mainly occurs in the northern part of the Qianjiadian Depression, a secondary tectonic unit within the Kailu Depression. Uranium deposits such as Qian II, Qian III, Qian IV, Qian V, and Baolongshan are successively developed there, all occurring around the Baixingtu tectonic window formed by the tectonic inversion at the end of the Late Cretaceous Nenjiang period. Figure 2 a). Uranium mineralization includes a consolidation and diagenesis pre-enrichment period (87±12 Ma and 81.2±2.6 Ma), a hydrocarbon seepage-ground oxidation mineralization period (74.5±4.8 Ma and 67±5 Ma), a regional inter-layer oxidation mineralization main mineralization stage (53 Ma-28 Ma), and continuous oxidation superimposed transformation (19 Ma-3 Ma).

[0064] Step Two: Field Core Observation and Sample Collection;

[0065] Based on the collected data, samples of diabase, mineral-bearing sandstone, thermally modified sandstone, and unmodified sandstone were collected through field core observations for subsequent analysis and testing.

[0066] Step 3: Evaluate the spatiotemporal relationship between intermediate-basic rock intrusion and alteration and uranium mineralization;

[0067] The sandstone-type uranium ore area in the southern Songliao Basin has a large number of diabase intrusive bodies, which are mainly controlled by faults in plan view, and are generally distributed in a northeast direction, overlapping with the uranium mineralization area. Figure 2 a); In the cross-section, the diabase cuts through the Yaojia Formation and the Nenjiang Formation, mainly intruding into the Nenjiang Formation and partially into the ore-bearing Yaojia Formation, appearing as dendritic interpenetrations within the ore-bearing strata, and uranium ore bodies are visible in the sandstone near the attached intrusive body ( Figure 2 (b, c) shows a close spatial correlation between diabase intrusion and uranium mineralization in the study area. Furthermore, whole-rock Ar-Ar dating of the collected diabase yielded plateau ages of 45.56±0.6 Ma, isochron ages of 42.63±0.81 Ma, and inverse isochron ages of 42.68±0.81 Ma, which show strong coupling with the main mineralization ages (53 Ma-28 Ma). This indicates a certain intrinsic correlation between diabase intrusion and sandstone uranium mineralization in the study area, paving the way for further evaluation.

[0068] Step 4: Evaluate the impact of intermediate-basic rock intrusion and alteration on the physical properties of the ore-bearing strata;

[0069] Porosity and permeability tests were conducted on the collected thermally modified and unmodified sandstone samples. The results showed that the porosity of the thermally modified red sandstone was 23.07% and the permeability was 820.9 mD, while that of the gray sandstone was 35.56% and the permeability was 956.2 mD. In contrast, the porosity of the unmodified red sandstone was 20.62% and the permeability was 394.6 mD, while that of the gray sandstone was 30.55% and the permeability was 673.2 mD. This indicates that the porosity and permeability of the thermally modified sandstone were both greater than those of the unmodified sandstone, suggesting that the diabase intrusion process can improve the physical properties of the sandstone, which is more favorable for the migration of ore-forming fluids and the uranium mineralization process.

[0070] Step 5: Evaluate the impact of intermediate-basic rock intrusion and alteration on groundwater migration;

[0071] Based on the borehole data collected in step one, a distribution map of the interlayer oxidation zones of uranium deposits in the study area was drawn. Figure 3 The groundwater migration pathway and recharge-drainage system were investigated. The cross-section showed an interlayer oxidation zone characterized by two yellow (red) zones sandwiching a gray zone, allowing for the identification of upper and lower oxidation zones. Figure 3 b, c, d, e), can be divided into regional interlayer oxidation zones and local interlayer oxidation zones on the plane ( Figure 3 a) This indicates that the study area is not only controlled by the groundwater dynamic system in the southern part of the basin, but also influenced by the local hydrodynamic system of Baixingtu-Jiamateu. Among them, the local interlayer oxidation zone is developed around the Jiamateu-Xiedai granite paleo-uplift, and local oxygenated groundwater flows outward along the paleo-uplift. The oxygenated groundwater on the west side generally migrates in a NW direction and discharges into the Baixingtu tectonic window. The regional interlayer oxidation zone generally extends in a NE-trending strip, starting from the southern edge of the basin and extending through Tongliao-Qianjiadian. It rapidly thins and pinches out towards the Baixingtu tectonic window, indicating that the southern edge of the basin is the recharge area for uranium-bearing and oxygenated groundwater, and the Baixingtu tectonic window is the discharge area. The groundwater generally migrates in a NE direction. Furthermore, the presence of numerous diabase intrusive bodies closely related to the temporal and spatial relationships of uranium mineralization within the sandstone-type uranium deposits on the southern margin of the Songliao Basin inevitably leads to an overall increase in groundwater temperature within the ore-bearing strata. This alters the existing gravity-driven groundwater dynamics, causing regional and local uranium-bearing oxygen-rich groundwater to undergo convective transport driven by heat. This not only accelerates groundwater transport speed and expands the scale of the regional inter-layer oxidation zone, forming upper and lower oxidation zones and their adjacent uranium ore bodies, but also causes the oxidation zone front to exhibit a serpentine distribution around the Baixingtu structural window, thus controlling the development of sandstone uranium mineralization. Therefore, the intrusive alteration of intermediate-basic rocks in the basin can locally change the transport mode and speed of uranium-bearing groundwater, thereby controlling and accelerating the formation of sandstone uranium mineralization, which is highly beneficial to sandstone uranium mineralization.

[0072] Step Six: Evaluate the impact of intermediate-basic rock intrusion and alteration on uranium mineralization;

[0073] For example, U and Th element content tests were conducted on diabase, thermally altered sandstone, and unthermally altered sandstone samples. The results showed that the U content of the diabase intrusion was extremely low (0.184-0.48 ppm), and the U / Th ratio was stable, indicating that the diabase intrusion itself could not provide uranium source for sandstone uranium mineralization. However, the U content of the thermally altered white sandstone (33.5 ppm, 12 ppm) was significantly higher than that of the unthermally altered red sandstone (6.18 ppm, 1.68 ppm), indicating that the hydrothermal fluids related to the diabase intrusion could provide part of the uranium source for uranium mineralization by extracting and activating uranium in the strata along the way, which is more favorable for sandstone uranium mineralization.

[0074] Scanning electron microscopy and electron probe microanalysis were conducted on the thermally altered sandstone samples. The results showed that the kaolinite-sodium aluminum-ferrodolomite and siderite in the sandstone were hydrothermal alteration mineral assemblages, indicating that the ore-bearing layer was subjected to large-scale CO2 influx. Subsequently, thermometry and laser Raman spectroscopy were performed on the primary inclusions in the carbonate cements such as ferrodolomite, which were altered by hydrothermal alteration. The results showed that the hydrothermal temperature was between 100-232℃ and the gas composition included CO2 and CH4. This indicates that the hydrothermal fluids related to the diabase intrusion were characterized by moderate temperature, strong reducing properties, and high CO2 and CH4 content. When the aforementioned ore-forming hydrothermal fluids migrate into the ore-bearing layer, on the one hand, the lower pressure causes CO2 and CH4 in the hydrothermal fluids to rapidly escape into the ore-bearing layer. The CO2 injection can form an acidic environment conducive to uranium adsorption and adsorbents such as kaolinite, while the injection of reducing gases such as CH4 increases the reducing capacity of sandstone, providing reducing substances and a favorable environment for subsequent uranium precipitation. On the other hand, the hydrothermal fluids can continuously extract dispersed adsorbed uranium and dissolve early-formed uranium minerals in the ore-bearing layer to form uranium-rich hydrothermal fluids. Uranium mainly migrates in the form of stable uranyl carbonate ions or as Ca-U(VI)-CO3 ternary complexes. The former is easy to precipitate in the form of pitchblende in pyrite, around organic matter, or as fine particles on the surface of adsorbents in areas of varying reducing capacity. The latter can form uranyl carbonate minerals or pitchblende around dolomite in areas of varying pH. Of course, uranium-rich hydrothermal fluids can also superimpose and enrich or remodel the uranium ore bodies formed in the early stages, forming high-grade and massive uranium accumulations in local areas.

[0075] Therefore, from the perspective of the uranium mineralization process of uranium activation (uranium source) - migration - enrichment and precipitation, the hydrothermal fluid formed by diabase intrusion can not only provide part of the uranium source for uranium mineralization, but also provide good mineralization conditions and environment for uranium migration - enrichment and precipitation, which is very favorable for the superposition and enrichment of uranium mineralization in sandstone.

[0076] Step 7: Comprehensive analysis and evaluation of the uranium mineralization effect of intrusion and alteration by basic rocks in sandstone-type uranium deposits.

[0077] For example, based on the close spatiotemporal relationship between diabase intrusion and uranium mineralization as identified in step three, and combined with the comprehensive analysis of the impact of basic rock intrusion on sandstone properties, groundwater migration, and uranium mineralization in steps four to six, it is believed that hydrothermal fluids related to diabase intrusion can not only provide some uranium sources for sandstone uranium mineralization and provide favorable mineralization conditions and environment for uranium migration, enrichment, and precipitation, resulting in superimposed enrichment or re-enlargement of uranium and the formation of high-grade, massive uranium deposits in local areas; they can also control and expand the scale of the original interlayer oxidation zone by improving sandstone properties and changing the mode and speed of groundwater migration, thereby controlling the formation and occurrence location of sandstone-type uranium deposits, and establishing a uranium mineralization model diagram of thermally driven convection by diabase intrusion in this area. Figure 4 The study points out that the exploration of sandstone-type uranium deposits in the study area should not only focus on inter-layer oxidized sandstone-type uranium deposits, but also prevent the omission of uranium ore bodies that have been strongly thermally modified or controlled by thermal modification during the exploration process. This provides new clues for expanding the exploration types and directions of sandstone-type uranium deposits in the intermediate-basic rock intrusion and modification areas.

[0078] Therefore, this invention not only elucidates the superimposed transformation and mineralization process of existing sandstone-type uranium deposits by hydrothermal fluids related to intermediate-basic rock intrusion from the perspective of uranium activation (uranium source)-migration-precipitation, controlling the formation of uranium ore bodies that are strongly thermally transformed or controlled by thermal transformation, but also emphasizes that intermediate-basic rock intrusion can change the mode and speed of groundwater transport to form and expand the scale of the original interlayer oxidation zone, controlling the formation and occurrence location of sandstone-type uranium deposits. Furthermore, it points out that the prospecting of sandstone-type uranium deposits in intermediate-basic rock intrusion-transformed areas should not only focus on interlayer oxidized sandstone-type uranium deposits, but also prevent the omission of uranium ore bodies that are strongly thermally transformed or controlled by thermal transformation during the exploration process, providing new clues for expanding the prospecting types and directions of sandstone-type uranium deposits in intermediate-basic rock intrusion-transformed areas.

[0079] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.

Claims

1. A method for evaluating the mineralization effect of intrusive-basic rocks in sandstone-type uranium deposits, characterized in that, The method includes: Step 1: Data collection, specifically: collecting borehole, seismic, and known uranium mineralization data for the study area, and preliminarily summarizing the spatial distribution characteristics of intermediate-basic rock intrusive bodies; Step 2: Field core observation and sample collection. Specifically, based on the data collected in Step 1, through field core observation, samples are collected from boreholes that have been intruded and modified by intermediate-basic rocks. The collected samples include intermediate-basic rocks, mineral-bearing sandstone, thermally modified sandstone, and unmodified sandstone samples. Step 3: Evaluate the spatiotemporal relationship between intermediate-basic rock intrusion and uranium mineralization. Specifically, based on the borehole and seismic data collected in Step 1 and the intermediate-basic rock samples collected in Step 2, draw a spatial distribution map of intermediate-basic rocks and ore bodies using a large amount of borehole data, conduct whole-rock Ar-Ar age determination of intermediate-basic rocks, and combine with existing uranium mineralization ages to determine the spatiotemporal coupling between intermediate-basic rocks and uranium mineralization in the study area. If the intermediate-basic rocks and uranium ore bodies are closely distributed spatially and have good temporal coupling, proceed to the subsequent evaluation steps; otherwise, proceed directly to Step 7. Step 4: Evaluate the impact of intermediate-basic rock intrusion and alteration on the physical properties of the ore-bearing layer. Specifically, conduct porosity and permeability studies on thermally altered and unthermally altered sandstone samples. By comparing the data, determine the impact of intermediate-basic rock intrusion and alteration on uranium mineralization of sandstone from the perspective of changes in the physical properties of the ore-bearing layer. Step 5: Evaluate the impact of intermediate-basic rock intrusion and alteration on groundwater migration and driving mechanisms. Specifically, this includes: determining the paleogroundwater migration path, migration mechanism, and hydrodynamic process by drawing a map showing the distribution characteristics of the interlayer oxidation zone in sandstone-type uranium deposits in the study area; and judging the impact of intermediate-basic rock intrusion and alteration on sandstone uranium mineralization from the perspective of changes in hydrodynamic characteristics. Step Six: Evaluate the impact of intermediate-basic rock intrusion and alteration on uranium mineralization, specifically including: determining whether intermediate-basic rock intrusion and alteration can provide uranium sources for uranium mineralization, whether it can provide favorable conditions for uranium migration, and whether it can provide a favorable environment for uranium enrichment and precipitation, and evaluate the impact of intermediate-basic rock intrusion and alteration on uranium mineralization; Step 7: Conduct a comprehensive analysis to evaluate the uranium mineralization effect of intermediate-basic rock intrusion in sandstone-type uranium deposits, and indicate the subsequent prospecting ideas and directions for the intermediate-basic rock intrusion intrusion area.

2. The method for evaluating the uranium mineralization effect of intrusion into basic rocks in sandstone-type uranium deposits according to claim 1, characterized in that, Step four specifically involves the following: when the porosity and permeability of the heated sandstone are greater than those of the unheated sandstone, it indicates that the intrusion and modification process of intermediate-basic rocks can improve the physical properties of the sandstone, which is beneficial to uranium mineralization in the sandstone; conversely, it cannot improve the physical properties of the sandstone, which is detrimental to uranium mineralization in the sandstone.

3. The method for evaluating the uranium mineralization effect of intrusion and alteration by intermediate-basic rocks in sandstone-type uranium deposits according to claim 1, characterized in that, Step five specifically involves: drawing a characteristic map of the distribution of oxidation zones between sandstone-type uranium deposits in the study area; using the planar distribution direction, size, and oxidation thickness of the ore-bearing layers in the oxidation zone profile to determine the direction and path of paleogroundwater migration; and determining the approximate locations of paleogroundwater recharge and discharge areas and the paleogroundwater dynamic system. For areas subjected to intrusion and alteration by intermediate-basic rocks, the changes in groundwater migration patterns caused by local thermal anomalies are used to determine whether they are favorable for sandstone uranium mineralization.

4. The method for evaluating the uranium mineralization effect of intrusion into basic rocks in sandstone-type uranium deposits according to claim 1, characterized in that, The question of whether the intrusion and alteration of intermediate-basic rocks can provide a uranium source for uranium mineralization in step six specifically involves: conducting comparative analyses of U and Th elemental contents in intermediate-basic rocks, thermally altered sandstone, and unthermally altered sandstone samples to evaluate whether the intermediate-basic rock intrusion can provide a uranium source for sandstone uranium mineralization. Specifically, if the U elemental content and U / Th ratio do not vary significantly among different intermediate-basic rock samples, and if the U elemental content and U / Th ratio do not vary significantly between thermally altered and unthermally altered sandstone samples, then the intermediate-basic rock intrusion and alteration cannot provide a uranium source for uranium mineralization; if the U elemental content and U / Th ratio vary significantly among different intermediate-basic rock samples... When the U content and U / Th ratio of thermally altered sandstone are greater than or significantly greater than those of unaltered sandstone samples, it indicates that intermediate-basic rock intrusion can provide a partial uranium source for sandstone uranium mineralization. When the U content and U / Th ratio of different intermediate-basic rock samples do not vary much, but the U content and U / Th ratio of thermally altered sandstone are greater than or significantly greater than those of unaltered sandstone samples, it indicates that the intermediate-basic rock itself cannot provide a uranium source for sandstone uranium mineralization, but the thermal fluids generated during the intrusion process of the intermediate-basic rock can extract uranium from the strata and provide a partial uranium source for sandstone uranium mineralization.

5. The method for evaluating the uranium mineralization effect of intrusion into intermediate-basic rocks in sandstone-type uranium deposits according to claim 1, characterized in that, Whether the intermediate-basic rock intrusion and alteration in step six can provide favorable conditions for uranium migration specifically involves: conducting homogenization temperature and laser Raman spectroscopy studies on the primary inclusions of hydrothermal alteration minerals in the thermally altered sandstone to identify the properties and composition of the hydrothermal fluids related to the intermediate-basic rock intrusion, and determining the stable migration forms and precipitation enrichment processes of uranium in the ore-forming hydrothermal fluids; wherein, when the hydrothermal fluid is Ca... 2+ In CO2-rich fluids with high content, U(VI) migrates in the form of a stable Ca-U(VI)-CO3 ternary complex, which is conducive to the long-term stable migration and enrichment of U(VI) into ore-forming fluids; when the alkalinity of the hydrothermal fluid is higher, the CO3 content is higher. 2- The higher the proportion, the better the extraction of uranium by the fluid and the oxidation of uranium minerals, and the easier it is to form stable uranyl carbonate complexes, which is conducive to the long-term stable migration and enrichment of U(VI) in the ore-forming fluid into ore. When the temperature increases, the stability constant of the uranyl carbonate complexation reaction increases, making the uranyl carbonate complex more stable, which is conducive to the long-term stable migration and enrichment of U(VI) in the ore-forming fluid into ore. However, the temperature should not be too high, as excessively high temperature can easily reduce the solubility of CO2, inhibit the formation of highly coordinated uranyl carbonate complexes, and is not conducive to the long-term stable migration and enrichment of U(VI) in the ore-forming fluid into ore.

6. A method for evaluating the uranium mineralization effect of intrusions into intermediate-basic rocks in sandstone-type uranium deposits according to any one of claims 1-5, characterized in that, Step seven specifically involves the following: If the intermediate-basic rock intrusion and uranium mineralization in Step three are inconsistent in both space and time, then it is considered that the intermediate-basic rock intrusion and sandstone uranium mineralization are not closely related; if the intermediate-basic rock intrusion and uranium mineralization in Step three have a good spatial relationship but inconsistent temporal relationship, then the influence of faults related to the intermediate-basic rock intrusion on sandstone uranium mineralization should be considered; if the intermediate-basic rock intrusion and uranium mineralization in Step three have a close spatiotemporal relationship, indicating that there is a certain intrinsic genetic connection between the intermediate-basic rock intrusion and sandstone uranium mineralization, then it is necessary to comprehensively analyze the impact of the intermediate-basic rock intrusion modification in Steps four to six on the physical properties of the ore-bearing strata, groundwater migration and driving mechanisms, and on uranium migration and enrichment in sandstone uranium mineralization, to clarify the uranium mineralization effect of the intermediate-basic rock intrusion modification in sandstone-type uranium deposits, and to comprehensively evaluate the impact of the intermediate-basic rock intrusion modification on the formation and preservation of sandstone-type uranium deposits; Based on the alteration of the original gravity-driven mechanism by intermediate-basic rock intrusion, and taking the groundwater-thermal-driven mechanism as the starting point, this paper establishes a thermally driven sandstone uranium mineralization model diagram of intermediate-basic rock intrusion, combining groundwater migration paths and recharge-pathway-discharge systems.

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