Sandstone type uranium metallogenic prospective area prediction method based on U content statistics

Abstract

The invention belongs to the technical field of sandstone-type uranium ore prospecting, and particularly relates to a sandstone-type uranium ore prospecting area prediction method based on U content statistics. The method comprises the following steps: 1, collecting and sorting previous and early-stage regional geological survey, uranium ore geological survey and uranium ore drilling data, and carrying out uranium prospecting target horizon optimization; 2, performing lithology-geochemical type division on uranium prospecting target layer sand-conglomerate according to characteristics such as metagenetic alteration; 3, counting U contents of the whole area and each lithology-geochemical type sand-conglomerate, and respectively drawing a U content cumulative probability curve graph; 4, performing comparative analysis on each lithology-geochemical type sand-conglomerate and the U content cumulative probability curve of the whole area, and dividing uranium emigration and migration types; 5, determining the lower limit of U abnormity of U immigration and emigration-immigration type sand-conglomerate; and 6, predicting a uranium metallogenic prospective area according to U immigration type sand-conglomerate abnormal sample distribution and regional uranium mineralization information.

Description

Technical Field

[0001] This invention belongs to the field of sandstone-type uranium exploration technology, and relates to a method for predicting sandstone-type uranium mineralization prospect areas based on U content statistics. Background Technology

[0002] Exploration of sandstone-type uranium deposits has achieved great success in monocline zones and interlayer oxidation zones at the margins of sedimentary basins. However, with continued investment in uranium resource exploration, new tectonic locations—such as basin-margin fold-thrust zones—and new genetic types—such as exudative types—are constantly emerging, increasing the complexity of sandstone-type uranium exploration. Therefore, there is an urgent need for a method for predicting potential mineralized areas of sandstone-type uranium based on U content statistics. This method would enable rapid identification of ore-bearing types from the numerous lithological and geochemical types of sandstone-conglomerate within complex tectonic settings, and accurate delineation of exploration areas, thereby improving the effectiveness of sandstone-type uranium exploration. Summary of the Invention

[0003] The main objective of this invention is to provide a method for predicting uranium mineralization potential areas in sandstone based on U content statistics. By statistically analyzing the U content of the main lithology and geochemical types of sandstone-conglomerate target layers for uranium exploration, the main mineralization types can be quickly identified, the exploration range can be accurately delineated, and uranium exploration prediction can be carried out.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for predicting uranium mineralization potential areas in sandstone-type formations based on U-content statistics includes six steps:

[0006] Step 1: Collect and organize previous regional geological surveys, uranium geological surveys and uranium drilling data, and divide stratigraphic units and select target strata for uranium exploration.

[0007] Step 2: Classify the sandstone-conglomerate layers of uranium exploration targets into lithological and geochemical types;

[0008] Step 3: Calculate the U content of sandstone and conglomerate in the entire area and for each lithology-geochemical type, and plot the cumulative probability curve of U content respectively;

[0009] Step 4: Comparative analysis of cumulative probability curves of U content in sandstone and conglomerate of various lithological and geochemical types with those of the whole area to classify uranium migration out and in types;

[0010] Step 5: Determine the U-migration type and the lower limit of the U-anomaly in sandstone-conglomerate of the migration-migration type;

[0011] Step 6: Based on the U-migration type, the distribution of anomalous sandstone-conglomerate samples of the migration-migration type, and regional uranium mineralization information, predict the uranium mineralization prospect area.

[0012] Step 1 involves collecting and organizing data from previous regional geological surveys, uranium geological surveys, and uranium drilling, and then dividing the stratigraphic units and selecting the target stratigraphic positions for uranium exploration.

[0013] (1.1) Within the predicted range, stratigraphic units are divided according to lithological assemblage and stratigraphic contact relationships;

[0014] (1.2) Based on the stratigraphic units divided in step (1.1), the target layers for uranium exploration are selected according to the sedimentary facies type. Stratigraphic units with braided fluvial sedimentary systems, braided deltaic sedimentary systems, fan deltaic sedimentary systems, and lacustrine (marine) deltaic sedimentary systems are selected as the target layers for uranium exploration.

[0015] (1.3) Based on the uranium prospecting target layer selected in step (1.2), the uranium prospecting target layer is further selected according to the alteration characteristics, and the stratigraphic unit with sand body development and post-oxidation alteration or post-reduction alteration characteristics is further selected as the uranium prospecting target layer.

[0016] (1.4) Based on the uranium exploration target layer selected in step (1.3), the uranium exploration target layer is further selected according to the uranium mineralization intensity in the sandstone, and the layer with the strongest uranium mineralization intensity is further selected as the uranium exploration target layer.

[0017] Step 2 involves classifying the lithological and geochemical types of the sandstone-conglomerate target layer for uranium exploration.

[0018] The requirement is to classify the sandstone and conglomerate layers selected for uranium exploration within the prediction range of Step 1 into lithological and geochemical types based on their authimorphic coloration and alteration mineral assemblage.

[0019] In step 3, the U content of sandstone and conglomerate in the whole area and in each lithology-geochemical type is statistically analyzed, and the cumulative probability curve of U content is plotted respectively.

[0020] (3.1) Calculate the cumulative probability of U content for the entire area and the sandstone-conglomerate of each lithology-geochemical type as divided in step (2) within a certain U content range and at certain intervals;

[0021] (3.2) Based on the statistical results of step (3.1), with U content as the abscissa and cumulative probability as the ordinate, draw the cumulative probability curves for the sandstone-conglomerate rocks in the whole area and the lithology-geochemical types divided in step (2).

[0022] In step 4, a comparative analysis of the cumulative probability curves of U content in each lithological-geochemical type and the entire area of ​​sandstone-conglomerate is conducted to classify uranium migration out and migration in types.

[0023] (4.1) For each lithology-geochemical type in step (3.2), the intersection points with the cumulative probability curve of sandstone-conglomerate in the whole area are respectively obtained, and each lithology-geochemical type is divided into four intersection types: upper intersection type, lower intersection type, double intersection type, and multiple intersection type.

[0024] (4.2) For the lithological-geochemical types classified in step (4.1), if the U content at any cumulative probability value in the main part below the upper intersection is less than that of the sandstone-conglomerate in the whole area, it is a uranium emigration type; otherwise, it is a uranium emigration type.

[0025] (4.3) For the lower intersection type lithology-geochemical type divided in step (4.1), if the U content at any cumulative probability value of the main part above the lower intersection is less than that of the sandstone-conglomerate in the whole area, it is a uranium emigration type; otherwise, it is a uranium emigration type.

[0026] (4.4) For the double-intersection lithological-geochemical types divided in step (4.1), if the U content at any cumulative probability value of the main part above the lower intersection and above the upper intersection is less than that of the sandstone-conglomerate in the whole area, it is a uranium emigration type; otherwise, it is a uranium emigration type.

[0027] (4.5) For the multi-intersection lithology-geochemical type classified in step (4.1), it is directly determined to be the uranium migration-immigration type;

[0028] Steps (4.2), (4.3), (4.4), and (4.5) are not in any particular order.

[0029] Step 5 involves determining the U-migration type and the lower limit of the U-anomaly in sandstone-conglomerate of the migration-migration type.

[0030] For the uranium migration type and uranium migration-exit type determined in step (4), the abnormal lower limit value is to be obtained according to the probability cumulative curve. If the probability cumulative curve is a two-segment curve, the U content at its inflection point is taken as the abnormal lower limit value; if the probability cumulative curve is a multi-segment curve, the U content at its lower inflection point is taken as the abnormal lower limit value.

[0031] Step 6, based on the U-migration type, the distribution of sandstone-conglomerate anomaly samples of the migration-migration type, and regional uranium mineralization information, predicts the uranium mineralization prospect area to provide the scope for further uranium resource investigation, evaluation and exploration work.

[0032] (6.1) Project the abnormal points in the uranium migration-immigration type and uranium migration-immigration type determined in step (5) that are higher than the lower limit of the abnormality onto the prediction plan map using mapping software;

[0033] (6.2) Review previous data and project sandstone-type uranium mineralization and anomaly information onto the prediction plan map using mapping software;

[0034] (6.3) Delineate the distribution range of the anomalies in step (6.1) and the uranium mineralization anomalies in step (6.2), and predict the prospective areas of sandstone-type uranium deposits, that is, delineate the areas that can be further investigated, evaluated and explored for uranium resources. Attached Figure Description

[0035] Figure 1 Flowchart of a method for predicting uranium mineralization potential areas in sandstone based on U content statistics;

[0036] Figure 2 Zoning map of sandstone-conglomerate lithology-geochemical type of the Kuqa Formation of the Pliocene in Baicheng area;

[0037] Figure 3 Cumulative probability curves of sandstone-conglomerate sandstone-conglomerate of the Upper Pliocene Kuqa Formation in Baicheng area for the whole region and for each type;

[0038] Figure 4 Diagram illustrating the migration-in / exit types of various sandstone-conglomerate types in the Kuqa Formation of the Pseudo-Conglomerate in the Baicheng area;

[0039] Figure 5 A diagram illustrating the abnormal lower limit of the migration in and out of the Kuqa group in the Baicheng area, specifically focusing on the migration type.

[0040] Figure 6 A prospective map of uranium mineralization in the Kuqa Formation of the Upper Series in the Baicheng area. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0042] This invention provides a method for predicting sandstone-type uranium mineralization potential areas based on U content statistics, such as... Figure 1 As shown, the method specifically includes the following steps:

[0043] Step 1: Collect and organize previous regional geological surveys, uranium geological surveys and uranium drilling data, and divide stratigraphic units and select target strata for uranium exploration.

[0044] (1.1) Within the predicted range, stratigraphic units are divided according to lithological assemblage and stratigraphic contact relationships;

[0045] In this example, the prediction area is the Baicheng region, the main tectonic unit is the Qiulitag tectonic belt, mainly distributed in the Cenozoic strata, and the main stratigraphic units can be divided into:

[0046] The Eocene Xiaokuzibai Formation is characterized by a fine clastic rock, marl, and gypsum assemblage with a red and purplish-red appearance, and is in conformable contact with the overlying Oligocene Suweiyi Formation.

[0047] Oligocene Suwei Formation: a sedimentary sequence of interbedded brownish-red sandstone, siltstone and mudstone, in conformable contact with the overlying Miocene Jidik Formation;

[0048] The Miocene Jidike Formation consists of a sedimentary sequence of fine clastic rocks and gypsum layers in alternating red and green hues, in conformable contact with the overlying Miocene Kangcun Formation.

[0049] The Zhongxintong Kangcun Formation consists of brownish-red mudstone interbedded with light gray sandstone and conglomerate sandstone, forming a continuous transitional depositional layer with the Shangxintong Kuqa Formation.

[0050] The Upper Pleistocene Kuqa Formation consists of alternating layers of brown, yellowish-brown, brownish-yellow, bluish-gray, and gray sandy mudstone, silty mudstone, and gray, light grayish-green sandstone, conglomerate sandstone, and conglomerate of varying thicknesses, in conformable to unconformable contact with the overlying Lower Pleistocene Xiyu Formation.

[0051] Lower Pleistocene Western Regions Formation: also known as the Western Regions Foothills Gravel Layer, composed of gray conglomerate and sandstone.

[0052] (1.2) Based on the stratigraphic units divided in step (1.1), the target layers for uranium exploration are selected according to the sedimentary facies type. Stratigraphic units with braided fluvial sedimentary systems, braided deltaic sedimentary systems, fan deltaic sedimentary systems, and lacustrine (marine) deltaic sedimentary systems are selected as the target layers for uranium exploration.

[0053] In this example, within the predicted range, the Eocene Xiaokuzibai Formation, the Oligocene Suweiyi Formation, and the Miocene Jidike Formation exhibit lagoonal and lacustrine sedimentary features characterized by fine clastic rocks, gypsum-salt rocks, and carbonate rocks; the Miocene Kangcun Formation and the Pliocene Kuqa Formation are fluvial deltaic deposits with stable "mud-sand-mud" structures, well-developed sand bodies, and good sand body connectivity and permeability; the Lower Pleistocene Xiyu Formation is an alluvial fan facies gravel and sand-gravel deposit. Based on the above, the Miocene Kangcun Formation and the Pliocene Kuqa Formation are preferred as the target layers for uranium prospecting.

[0054] (1.3) Based on the uranium prospecting target layer selected in step (1.2), the uranium prospecting target layer is further selected according to the alteration characteristics, and the stratigraphic unit with sand body development and post-oxidation alteration or post-reduction alteration characteristics is further selected as the uranium prospecting target layer.

[0055] In this example, within the prediction range, both the Kangcun Formation of the Neogene and the Kuche Formation of the Pseudogene, selected as the target uranium prospecting layers in step (1.2), have undergone post-oxidation. Therefore, these two are further selected as the target uranium prospecting layers.

[0056] (1.4) Based on the uranium prospecting target layer selected in step (1.3), the uranium prospecting target layer is further selected according to the uranium mineralization intensity in the sandstone, and the layer with stronger uranium mineralization intensity is further selected as the uranium prospecting target layer.

[0057] In this example, within the prediction range, based on the uranium prospecting target layer selected in step (1.3), the uranium mineralization intensity of the Kangcun Formation of the Neogene and the Kuqa Formation of the Upper Neogene is uranium anomaly and uranium industrial mineralization, respectively. The uranium mineralization intensity of the Kuqa Formation of the Upper Neogene is stronger than that of the Kangcun Formation of the Neogene. Therefore, the Kuqa Formation of the Upper Neogene is further selected as the uranium prospecting target layer.

[0058] Step 2: Classify the sandstone-conglomerate layers of uranium exploration targets into lithological and geochemical types;

[0059] The task is to classify the sandstone and conglomerate layers selected for uranium exploration within the prediction range of Step 1 into lithological and geochemical types based on their authimorphic color, alteration mineral assemblage, and spatial distribution patterns.

[0060] In this embodiment, within the predicted range, based on the selected uranium prospecting target layer in step 1, the Kuqa Formation sandstone-conglomerate of the Neogene is divided into the following lithological-geochemical types from north to south according to authigenic color (primary and secondary colors), alteration mineral assemblage, and spatial distribution: Brownish-red type, with secondary colors of brownish-red and light brownish-red, exhibiting hematite and strong clay mineralization; Grayish-white type, with secondary colors of grayish-white, exhibiting strong clay mineralization; Brownish-yellow type, with secondary colors of brownish-yellow and light brownish-yellow, exhibiting strong limonite and clay mineralization; Light yellow type, with secondary colors of light yellow, exhibiting weak limonite and clay mineralization; Gray type, with primary colors of gray and light gray, exhibiting weak clayification or poorly developed post-alteration. The sandstone-conglomerate of each lithological-geochemical type is distributed in an east-west banded pattern and an orderly north-south distribution in the plane. Figure 2 This study shows the spatial distribution characteristics of sandstone and conglomerate of various lithological and geochemical types in the Kuqa Formation of the Pliocene.

[0061] Step 3: Calculate the U content of sandstone and conglomerate in the entire area and for each lithology-geochemical type, and plot the cumulative probability curve of U content respectively;

[0062] (3.1) For the entire area and the sandstone-conglomerate of each lithology-geochemical type divided in step (2), the cumulative probability of U content is statistically calculated in groups according to a certain interval within a certain U content range. The cumulative probability statistical formula is as follows;

[0063]

[0064] Where: m – group number;

[0065] P m - Cumulative probability of the first m groups (in %);

[0066] X i - Frequency of the i-th sample group;

[0067] n – Total number of samples;

[0068] U m - Upper limit of uranium content in group m (unit: ×10) -6 );

[0069] U0 – Minimum uranium content in the sample (unit: ×10) -6 );

[0070] △ U - Grouping interval (unit: ×10) -6 Take 0.5 × 10 -6 1×10 -6 ...

[0071] In this embodiment, the U content of sandstone and conglomerate in the entire area, as well as the brownish-red, grayish-white, brownish-yellow, light yellow, and gray types classified according to step (2), was statistically analyzed. The statistical U content range was (0~32)×10⁻⁶. -6 The grouping interval is 0.5 × 10⁻⁶. -6 The sample sizes were 1389, 136, 421, 222, 40, and 570 respectively. The statistical items included the sample size and cumulative probability for each interval. The cumulative probability statistics for the entire region, reddish-brown type, grayish-white type, brownish-yellow type, light yellow type, and gray type sandstone-conglomerate are shown in Tables 1, 2, 3, 4, 5, and 6 respectively.

[0072] Table 1. Cumulative probability statistics of U content in sandstone and conglomerate throughout the region.

[0073]

[0074]

[0075] Table 2. Cumulative Probability Statistics of U Content in Brownish-Red Types

[0076]

[0077]

[0078] Table 3. Cumulative Probability Statistics of U Content in Grayish-White Types

[0079]

[0080] Table 4. Cumulative Probability Statistics of U Content in Brownish-Yellow Types

[0081]

[0082]

[0083] Table 5. Cumulative Probability Statistics of U Content in Light Yellow Type

[0084]

[0085] Table 6. Cumulative Probability Statistics of U Content in Gray Types

[0086]

[0087]

[0088] (3.2) Based on the statistical results of step (3.1), with the upper limit of U content in the group (Um) as the abscissa and the cumulative probability of U content (Pm) as the ordinate, the cumulative probability curves of the whole area and the sandstone-conglomerate of each lithology-geochemical type divided in step (2) are plotted respectively.

[0089] In this embodiment, the aforementioned statistical data is used to plot a cumulative probability curve in an Excel spreadsheet. Figure 3 The cumulative probability curves for the entire region and for each lithology-geochemical type are shown.

[0090] Step 4: Compare and analyze the cumulative probability curves of U content in sandstone and conglomerate of each lithology-geochemical type with those of the whole area to classify uranium migration out and in types;

[0091] (4.1) For each lithological-geochemical type of sandstone-conglomerate in step (3.2), the intersection points are calculated with the cumulative probability curves of sandstone-conglomerate in the whole region. Each lithological-geochemical type is divided into four intersection types: upper intersection type, lower intersection type, double intersection type, and multiple intersection type. For the upper intersection type of lithological-geochemical type, its cumulative probability curve of U content has one intersection point with the cumulative probability curve of U content of sandstone-conglomerate in the whole region, and the U content at the intersection point is greater than the U content at the inflection point of the two cumulative probability curves. For the lower intersection type of lithological-geochemical type, its cumulative probability curve of U content has one intersection point with the cumulative probability curve of U content of sandstone-conglomerate in the whole region. The cumulative probability curves of U content in rocks have one intersection point, and the U content at the intersection point is less than the U content at the inflection point of the two cumulative probability curves; the double-intersection lithological-geochemical type has two intersection points with the cumulative probability curves of U content in sandstone-conglomerate rocks across the region, with the U content at one intersection point being greater than the U content at the inflection point of the two cumulative probability curves, and the U content at the other intersection point being less than the U content at the inflection point of the two cumulative probability curves; the multi-intersection lithological-geochemical type has three or more intersection points with the cumulative probability curves of U content in sandstone-conglomerate rocks across the region.

[0092] In this embodiment, the cumulative probability curves of U content for the grayish-white and gray types intersect the cumulative probability curve of U content for sandstone and conglomerate throughout the region at only one point, where the U content is greater than that at each inflection point, belonging to the upper intersection type of lithology-geochemistry. The cumulative probability curve of U content for the light yellow type intersects the cumulative probability curve of U content for sandstone and conglomerate throughout the region at only one point, where the U content is less than that at each inflection point, belonging to the lower intersection type of lithology-geochemistry. The cumulative probability curve of U content for the brownish-red type intersects the cumulative probability curve of U content for sandstone and conglomerate throughout the region at two points, where the U content is less than that at each inflection point in one intersection and greater than that at the inflection point in the other intersection, belonging to the double intersection type of lithology-geochemistry. The cumulative probability curve of U content for the brownish-yellow type intersects the cumulative probability curve of U content for sandstone and conglomerate throughout the region at three points, belonging to the multi-intersection type of lithology-geochemistry.

[0093] (4.2) For the lithological-geochemical types classified in step (4.1), if the U content at any probability value of the main part below the upper intersection is less than that of the sandstone-conglomerate in the whole area, it is determined to be a uranium emigration type; otherwise, it is determined to be a uranium emigration type.

[0094] In this embodiment, the intersection type belongs to the upper intersection type lithological-geochemical type, including gray-white type and gray type; at any cumulative probability point in the main part of the cumulative probability curve of U content in gray-white type, the U content is less than that in sandstone-conglomerate throughout the area, which is uranium emigration type; at any cumulative probability point in the main part of the cumulative probability curve of U content in gray type, the U content is greater than that in sandstone-conglomerate throughout the area, which is uranium emigration type.

[0095] (4.3) For the lower intersection type lithology-geochemical type divided in step (4.1), if the U content is less than that of sandstone-conglomerate in the whole area at any probability value of the main part above the lower intersection, it is determined to be a uranium emigration type; otherwise, it is determined to be a uranium emigration type.

[0096] In this embodiment, the lower intersection geochemical type includes the light yellow type. At any cumulative probability point in the main part of the light yellow type, the U content is less than that of the sandstone-conglomerate in the whole area, which is the uranium migration type.

[0097] (4.4) For the double-intersection lithological-geochemical types divided in step (4.1), if the U content at any probability value of the main part above the lower intersection and above the upper intersection is less than that of the sandstone-conglomerate in the whole area, it is determined to be a uranium emigration type; otherwise, it is determined to be a uranium emigration type.

[0098] In this embodiment, the dual-intersection geochemical type includes the brownish-red type. At any cumulative probability point in the main part of the brownish-red type, the U content is less than that of the sandstone-conglomerate in the whole area, which is a uranium-migrating type.

[0099] (4.5) For the multi-intersection lithology-geochemical type classified in step (4.1), it is directly determined to be the uranium migration-immigration type;

[0100] In this embodiment, the multi-intersection lithology-geochemical type includes the brownish-yellow type, which is directly identified as the uranium emigration-migration type;

[0101] Steps (4.2), (4.3), (4.4), and (4.5) are not in any particular order. Figure 4 A diagram illustrating the differentiation of migration types for each lithological-geochemical type is provided.

[0102] Step 5: Determine the U-migration type and the lower limit of the U-anomaly in sandstone-conglomerate of the migration-migration type;

[0103] For the uranium migration-in type and uranium migration-out-migration type determined in step (4), the lower limit of the anomaly should be obtained by using the iterative method or the probability cumulative curve graphical method respectively.

[0104] The formula for finding the lower limit of anomalies using the iterative method is as follows:

[0105] U t =U l U l ≥MAX(U i ), l=1, 2..., i=1, 2...n l ;

[0106]

[0107] In the formula: U t - Lower limit of abnormal uranium content in samples (unit: ×10) -6 );

[0108] U l - Lower limit of uranium content anomaly in iteration l (unit: ×10) -6 );

[0109] l—number of iterations; i—sample number; n l —The total number of samples in the l-th iteration;

[0110] - Arithmetic mean of uranium content in iteration l (unit: ×10) -6 );

[0111] U i - Uranium content of the i-th sample (unit: ×10) -6 );

[0112] S l - The root mean square error of uranium content in the l-th iteration (unit: ×10) -6 );

[0113] The method for determining the lower limit of anomalies using the cumulative probability curve is as follows: take the U content value at the inflection point of the cumulative probability curve as the lower limit of anomalies.

[0114] In this embodiment, the lower limit of anomalies obtained by iterating 11 times for the gray type of uranium migration-in and 14 times for the brownish-yellow type of migration-exit, is 9.85 × 10⁻⁶. -6 4.47×10 -6 The results are consistent with those obtained by the cumulative probability curve graphical method. Figure 5 ).

[0115] Step 6: Based on the U-migration type, the distribution of sandstone-conglomerate anomaly samples of the migration-migration type, and regional uranium mineralization information, predict the uranium mineralization prospect area to provide the scope for further uranium resource investigation, evaluation and exploration work.

[0116] (6.1) Project the abnormal points in the uranium migration-immigration type and uranium migration-immigration type determined in step (5) that are higher than the lower limit of the abnormality onto the prediction plan map using mapping software;

[0117] (6.2) Project the sandstone-type uranium mineralization and anomaly information onto the prediction plan map using mapping software;

[0118] (6.3) Delineate the distribution range of the anomaly points in step (6.1) and the uranium mineralization anomaly information in step (6.2), and predict the prospective area of ​​sandstone-type uranium deposits, that is, delineate the area that can be further investigated, evaluated and explored for uranium resources.

[0119] In this embodiment, the abnormal points of uranium migration-in (gray type), migration-out (brownish-yellow type) samples, and regional uranium mineralization information are projected onto a prediction plan map to predict a uranium mineralization prospect area: the Ridarik-Wenbash uranium mineralization prospect area. Figure 6 The results show the predicted sandstone-type uranium deposits in the Kuqa Formation of the Pseudo-Series in the Baicheng area.

[0120] Therefore, compared with existing technologies, the sandstone-type uranium mineralization prospect prediction method provided by this invention can minimize human interference factors such as genetic judgment, make full use of existing data within the prediction range, classify sandstone-conglomerate lithology-geochemical types, and quickly and objectively identify the lithology-geochemical type of uranium enrichment mineralization from sandstone-conglomerate by statistically analyzing the cumulative probability of U element and plotting cumulative probability curves, thereby carrying out uranium mineralization prediction work and greatly improving the prospecting results of sandstone-type uranium deposits.

[0121] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for predicting potential uranium deposits in sandstone-type deposits based on U content statistics, characterized in that, The method consists of six steps: (1) Collect and organize previous regional geological surveys, uranium geological surveys and uranium drilling data, and select the target stratigraphic position for uranium prospecting; (2) Classify the sandstone-conglomerate target layer of uranium exploration by lithology and geochemical type; (3) Statistical analysis of U content in sandstone and conglomerate of the whole region and each lithological-geochemical type was performed, and cumulative probability curves of U content were plotted respectively. (4) Comparative analysis of cumulative probability curves of U content in sandstone-conglomerate of various lithological and geochemical types and the whole area, and classification of uranium migration type and uranium migration type; (5) Determine the U-migration type and the lower limit of U-anomaly in sandstone-conglomerate of the in-migration-out type; (6) Based on the U migration type, the distribution of sandstone-conglomerate anomaly samples of migration-exit type, and regional uranium mineralization information, predict the uranium mineralization prospect area.

2. The method for predicting sandstone-type uranium deposit prospective areas as described in claim 1, characterized in that, Step (1) specifically includes the following steps: (1.1) Within the predicted range, collect previous and earlier regional geological surveys, uranium geological surveys and uranium drilling data, and divide the main stratigraphic units; (1.2) Based on the main stratigraphic units divided in step (1.1), they are sorted according to sedimentary facies type. Braided river delta deposits are superior to braided river plain deposits, and braided river plain deposits are superior to fan delta deposits and normal delta deposits. (1.3) Based on the main stratigraphic units divided in step (1.1), they are sorted according to alteration type. Those with both post-oxidation and post-reduction are better than those with only post-oxidation, and those with only post-oxidation are better than those with only post-reduction. (1.4) Based on the main stratigraphic units divided in step (1.1), sort them according to mineralization information. The industrial uranium mineralization layer is superior to the uranium mineralization layer, and the uranium mineralization layer is superior to the uranium anomaly layer. (1.5) Based on the sorting results of steps (1.2), (1.3), and (1.4), the target layer for uranium exploration is selected.

3. The method for predicting sandstone-type uranium deposit prospect areas as described in claim 2, characterized in that, Step (2) requires systematically reviewing previous data and classifying the lithological and geochemical types of sandstone-conglomerate strata with prospecting targets selected in the prediction range determined in step (1).

4. The method for predicting sandstone-type uranium deposit prospect areas as described in claim 3, characterized in that, Step (3) specifically includes the following steps: (3.1) The cumulative probability of U content in the sandstone-conglomerate rocks of the whole area and the lithological types divided in step (2) is calculated at certain intervals within a certain range of U content. (3.2) Based on the statistical results of step (3.2), with U content as the abscissa and cumulative probability as the ordinate, draw the cumulative probability curves for the sandstone-conglomerate rocks in the whole area and the lithological types divided in step (2).

5. The method for predicting sandstone-type uranium deposit prospect areas as described in claim 4, characterized in that, Step (4) specifically includes the following steps: (4.1) The cumulative probability curves of each lithology type in step (3.2) are intersected with the sand-conglomerate of the whole area, and the cumulative probability curves of each lithology type are classified into the following types: the upper intersection type with only upper intersection, the lower intersection type with only lower intersection, the double intersection type with both upper and lower intersections, and the multi-intersection type with 3 or more intersections. (4.2) For the lithological types classified in step (4.1), if the U content at any probability value of the main part below the upper intersection is less than that of the sandstone-conglomerate in the whole area, it is a uranium emigration type; otherwise, it is a uranium emigration type. (4.3) For the lower intersection type lithology classified in step (4.1), if the U content at any probability value of the main part above the lower intersection is less than that of the sand-conglomerate in the whole area, it is a uranium emigration type; otherwise, it is a uranium emigration type. (4.4) For the double-intersection type lithology classified in step (4.1), if the U content at any probability value of the main part above the lower intersection and above the upper intersection is less than that of the sand-conglomerate in the whole area, it is a uranium emigration type; otherwise, it is a uranium emigration type. (4.5) For the multi-intersection lithological types classified in step (4.1), they are directly identified as uranium migration-immigration types; Steps (4.2), (4.3), (4.4), and (4.5) are not in any particular order.

6. The method for predicting sandstone-type uranium deposit prospect areas as described in claim 5, characterized in that, Step (5) requires that for the uranium migration type and uranium migration-exit type determined in step (4), the abnormal lower limit value be obtained according to the probability cumulative curve. If the probability cumulative curve is a two-segment curve, the U content at its inflection point is taken as the abnormal lower limit value; if the probability cumulative curve is a multi-segment curve, the U content at its lower inflection point is taken as the abnormal lower limit value.

7. The method for predicting sandstone-type uranium deposit prospect areas as described in claim 6, characterized in that, Step (6) specifically includes the following steps: (6.1) Project the abnormal points in the uranium migration-in type and uranium migration-out-migration type determined in step (5) that are higher than the lower limit of the abnormality onto the prediction plane map using mapping software; (6.2) Review previous data and project sandstone-type uranium mineralization and anomaly information onto the prediction plan map using mapping software; (6.3) Determine the distribution range of the anomalies in step (6.1) and the uranium mineralization anomalies in step (6.2) to predict the prospective areas of sandstone-type uranium deposits.

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