CN113109889B

CN113109889B - Sandstone-type uranium ore prospecting method based on 'two-stage and two-mode' mineralization model

Info

Publication number: CN113109889B
Application number: CN202110447543.8A
Authority: CN
Inventors: 聂逢君; 夏菲; 严兆彬; 何剑锋; 封志兵; 张成勇; 张鑫; 杨东光
Original assignee: East China Institute of Technology
Current assignee: East China Institute of Technology
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2021-12-21
Anticipated expiration: 2041-04-25
Also published as: CN113109889A

Abstract

The invention discloses a sandstone-type uranium ore prospecting method based on a 'two-stage and two-mode' mineralization model, which comprises four steps of mineralization attribute positioning, mineralization model establishment, target area prediction and drilling verification: step one, positioning the mineralization attribute: respectively carrying out ore forming attribute positioning according to ore control factors; step two, establishing an ore forming model: establishing a 'dual-stage and dual-mode' mineralization model, and establishing a surface-generated oxidation fluid mineralization model and a thermal fluid superposition transformation mineralization model; step three, target area prediction: target area prediction is carried out according to a 'double-stage and double-mode' mineralization model; step four, drilling verification: and (4) verifying the composition of the mineral phase by drilling. The invention provides a 'two-stage and two-mode' uranium ore formation theory, develops and integrates an ore formation combination key technology suitable for sandstone-type uranium ores, establishes ore formation models of different types of sandstone-type uranium ore deposits, and establishes a corresponding ore formation mode. The method is popularized and applied in China's Panels such as the Erlian, Kailu, Bayin Gobi and the like and Nigerl Arzerk uranium resource exploration, so that great economic and social benefits are obtained, the exploration cost is saved, and the prospecting period is shortened.

Description

Sandstone-type uranium ore prospecting method based on 'two-stage and two-mode' mineralization model

Technical Field

The invention relates to the technical field of mining detection, in particular to a sandstone-type uranium ore prospecting method based on a 'two-stage and dual-mode' mineralization model.

Background

Sandstone-type uranium ores are one of four major uranium ore types in China. Since the 90 s of the 20 th century, the uranium ore exploration in China changed from the attack of hard rock type uranium ore in the south to sandstone type uranium ore in the north. The ore searching and exploration work of the sandstone-type uranium ores in the sedimentary basin in the north is constantly growing and has remarkable achievement. The proportion of the sandstone-type uranium ore resource quantity in the four major uranium ore types in China has been changed from the previous third place to the first place. Such uranium deposits have become the focus of uranium ore exploration in China. Sandstone-type uranium deposits produced in the eastern basin in the north of China have similar characteristics but are obviously different from uranium deposits produced in the northwest of China. Therefore, it is necessary to develop research on uranium mineralization and an ore exploration method for basins in the east of the north of China. In addition, the uranium ore exploration and research work carried out overseas by going out of China can provide important supplement for uranium resources in China.

Disclosure of Invention

The invention aims to provide a sandstone-type uranium ore prospecting method based on a 'two-stage and dual-mode' mineralization model, provides a 'two-stage and dual-mode' uranium mineralization theory, develops and integrates a prospecting combination key technology suitable for sandstone-type uranium ores, establishes different types of sandstone-type uranium ore deposit mineralization models, and establishes corresponding prospecting modes. The method is popularized and applied in China's Panels such as the Erlian, Kailu, Bayin Gobi and the like and Nigerl Arzerk uranium resource exploration, so that great economic and social benefits are obtained, the exploration cost is saved, and the prospecting period is shortened.

The invention is realized by the following technical scheme: a sandstone-type uranium ore prospecting method based on a 'two-stage and dual-mode' mineralization model comprises four steps of mineralization attribute positioning, mineralization model establishment, target area prediction and drilling verification:

step one, positioning the mineralization attribute: respectively carrying out ore forming attribute positioning according to ore control factors;

step two, establishing an ore forming model: establishing a 'dual-stage and dual-mode' mineralization model, and establishing a surface-generated oxidation fluid mineralization model and a thermal fluid superposition transformation mineralization model;

step three, target area prediction: target area prediction is carried out according to a 'double-stage and double-mode' mineralization model;

step four, drilling verification: and (4) verifying the composition of the mineral phase by drilling.

Further preferably, in the first step, the ore control factors comprise ore-adding sand, an oxidation zone, a uranium source, a reducing agent and hot fluid transformation, and the first step comprises the following processes:

(1) the method comprises the following steps of (1) evaluating the space-time distribution characteristics of a sand body storage space through geophysical methods (heavy, magnetic, electric and seismic), well logging curve analysis and sedimentary facies and microphase research of a target layer sand body, so as to realize storage space positioning;

(2) an oxidation zone, namely analyzing the color change of sandstone through core observation and analysis, counting various data related to sand bodies, drawing a lithofacies paleogeographic map, researching paleohydrodynamic conditions for the growth of uranium-containing oxygen-containing fluid, predicting the development position of a front line before oxidation by combining the growth rule of the sand bodies, and realizing the positioning of the migration direction;

(3) the uranium source is a basic condition formed by sandstone-type uranium deposit, and the abundance degree of the uranium source is judged through analyzing and researching the uranium content of an erosion source region, a hidden erosion source region (covered by a later stratum) and the self uranium content of sand body by field geological survey sampling of the erosion source region, so that the mineralization potential is evaluated, and the material condition positioning is realized;

(4) the mineralizing effect of the reductant-uranium is U⁶⁺Is converted into U⁴⁺Therefore, the amount and type of reducing agent in the stratum has influence on the mineralized uranium; researching the change of the paleoclimate, tracking the development condition of carbon dust in the stratum, the existence of low-valence sulfides, particularly the existence of pyrite and marcasite, researching whether oil gas enters a target layer or not, and realizing the location of reduction enrichment;

(5) thermal fluid modification-the study of conditions of thermal fluid development, such as deep fracture and basal magma activity, marks left by thermal fluid-rock interaction, crustal stretch-fracture effect and increase of heat flow values in large areas and basin ranges, creates conditions for the superposition modification of early mineralization by thermal fluid, and realizes modification positioning.

In the second step of the invention, a double mineralization theory of oxidation before reformation is provided: breaking the single epibiotic oxidation fluid induced ore of basin sandstone-type uranium ores, and establishing a thermal fluid ore formation model at the later stage of epibiotic oxidation ore formation stacking; uranium mineralization is relevant with later stage hot fluid transformation, and after basin deposit reversal lifting formed surface oxidation fluid mineralization, basin stretches once more and leads to fracture magma activity, and deep hot fluid rises and adds the transformation mineralization to surface formation ore, and two mineralization effects of "transformation after oxidation" have promptly enlarged the ore body scale, have changed ore body form and spatial position.

In the second step of the invention, the dual ore control understanding of 'extrusion before extension' is provided: breaks through the single 'secondary mountain making' slope-lifting ore control function of basin sandstone-type uranium ores, and provides a new understanding of multi-phase 'extrusion-extension' structure superposition ore control; forming an ore-containing target layer in the basin under the extending background, and providing an ore containing space for later-stage uranium gathering and ore forming; the extrusion effect in late chalkiness-early ancient period leads to the 'tilting' of the target layer and the infiltration of the oxygen-containing fluid containing uranium on the surface into the ore; since the late ancient time, the basin stretches again, and the thermal tectonic event causes the hot fluid to upwelle and overlap to cause the ore; on the basis, a new 'two-stage' model is established, wherein an ore storage target layer is formed under the extrusion background, and an oxidation ore forming and hot fluid superposition ore forming are performed under the stretching background.

In the second step of the invention, a 'two-stage double-mode' ore-forming theory is established, and a new 'two-stage double-mode' ore-forming model of oxidation ore-forming under the regional extrusion background and thermal fluid superposition under the large-scale stretching background is established; a basin uranium deposit 'dual-stage and dual-mode' mineralization model is as follows: the basin forms an ore-containing target layer mainly comprising braided rivers and braided delta sands under the background of early chalkiness and late chalkiness;

first stage-interbed infiltration oxidation mineralization stage: the squeezing action of late chalkiness, early in the past, is accompanied by a strong inversion of formation, causing the target layer to lift and degrade, exposing the surface at the edge of the basin, and receiving the infiltration of uranium-containing oxygenated fluids. Uranium-containing oxygen-containing fluid from a uranium source region continuously flows and is discharged in a permeable layer, and uranium is reduced, adsorbed and enriched in an oxidation-reduction transition zone to form a rolled uranium ore body;

the second stage is a hot fluid superposition transformation mineralization stage: since late in the ancient period, basins are stretched again, the construction activity is strong, each basin has large-scale basal magma activity, the fluid rises along the fracture, the fluid interacts with the ore-containing layer, a large amount of hydrothermal alteration minerals appear, meanwhile, the original uranium ore body is strongly overlapped and modified, and the shape of the ore body is modified into a plate shape or a lens shape from a roll shape.

The third step adopts radioactive ore prospecting technology, ground high-precision gravity ore prospecting technology and CSAMT ore prospecting technology; different types of sandstone type uranium deposit prospecting modes include: the ore searching mode of the braided river sandstone type uranium ore is 'model +' + CSAMT + sedimentary microfacies + ground high-precision gravity + soil thermoluminescence; the ore searching mode of shallow burial shore shallow lake sandstone type uranium ore is 'model +' + vehicle-mounted gamma energy spectrum + structure interpretation + sedimentary microfacies; the ore searching mode of the braided delta sandstone type uranium ore is 'model +' + uranium source + sedimentary microfacies + ground high-precision gravity.

The invention has the beneficial effects that: the theory of double mineralization of oxidation before reformation is provided: breaking the single epibiotic oxidation fluid induced ore of basin sandstone-type uranium ores, and establishing a new theory of thermal fluid mineralization at the later stage of epibiotic oxidation ore formation stacking; the double ore control understanding of 'extrusion before stretching' is provided: breaks through the single 'secondary mountain making' slope-lifting ore control function of basin sandstone-type uranium ores, and provides a new understanding of multi-phase 'extrusion-extension' structure superposition ore control; a 'two-stage double-mode' ore-forming theory is established, and a 'two-stage double-mode' new ore-forming model of oxidation ore-forming under the regional extrusion background and thermal fluid superposition under the large-scale stretching background is established. By taking the space-time evolution of the sedimentary basin as the background, on the basis of practice verification of various ore exploration methods, a superficial identification technology of a sandstone-type uranium ore deep blind ore body is established. Establishing identification marks of shallow weak information of various types of uranium deposit deeply-buried ore bodies in different deposition systems and deposition phases under the background of stretching and sliding structures; a uranium mineralization model of a duplex basin and a Bartonegobi basin is established, an ore exploration mode which is suitable for uranium ores of different types is established on the basis of the model and in combination with a specific ore exploration method, an ore exploration prospect is predicted, and successful verification is achieved. The method is popularized and applied to exploration of the uranium resources such as the basin of the second run, the Kailu, the Bayinggobi and the like and Nigerl Arzerk in China, so that great economic and social benefits are obtained, the exploration cost is saved, and the ore exploration period is shortened.

Drawings

FIG. 1 is a schematic overview of the process of the present invention.

Fig. 2 shows the results of natural thermoluminescence measurements of soil from section 48 of a uranium 511 deposit.

Figure 3 shows the results of the measurement of the typical soil Thermoluminescence (TL) and natural potential (Eh) on the dyad of diben-bayan sandstone uranium ore.

Fig. 4 is a 512 deposit 32-line soil Thermoluminescence (TL) and natural potential (Eh) measurement profile.

Fig. 5 is a schematic diagram of ground gravity and CSAMT profile layout.

FIG. 6 is a graph of the Bartoney Goniobic basin delignification deposit formation process and pattern.

Figure 7 is a two-basin crust Bayan deposit model.

Fig. 8 is a kailu basin change shop-baolongshan mineral deposit mineralization model.

FIG. 9 is a graph of uranium mineralization patterns in the lignin region of the Banyin Gobi basin tower.

Fig. 10 is a two-pot floor hadamard plot deposit mineralization model.

FIG. 11 is a diagram of a new heat fluid reforming into an ore model from the beginning of the Kailu basin.

Fig. 12 is a diagram of a nigeralgaer basin aliskirt mineralization model.

FIG. 13 is a diagram showing a case of thermal fluid mineralization at a later stage of the superposition of the raw oxidation mineralization.

FIG. 14 is a diagram of the evolution of the northern east stretch-squeeze-stretch configuration versus uranium mineralization pattern.

FIG. 15 is a "two-stage dual-mode" mineralization model of sedimentary basins in the east of the northern China.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

the complex variability of the ore-forming environment of the northern sandstone-type uranium ores in China determines that the ore-finding thought of the northern sandstone-type uranium ores has to be innovated on the basis of the theory of the middle-sublevel oxidation zone and the theory of the American coiled sandstone-type uranium ores. The method for finding the ore in the middle and Asia regions is mainly based on the theory of 'secondary mountain making', and is characterized by utilizing drilling technology and a partial post-alteration geochemical zonation method. The sand body distribution rule formed in the sea-land transitional phase environment is easy to master, and the success rate of drilling is high.

In the late 1980 s to early 1990 s, China mainly introduces the theory of ore formation and the method of finding ore in Zhongya, and once a large amount of drilling work is deployed in many areas in northwest and northeast China, the effect is very little, and the main reason is that the background condition characteristics of the ore formation in China cannot be fully considered. In the late 1990 to early 2000, the research on the mineralogical conditions, particularly the research on the deposition system of a target layer and the distribution rule of sand bodies, is strengthened, and the research is matched with a drilling technology, so that the good effect is achieved in the jungle basin, the Kailu basin and the Bartonegobi basin. In order to better master the ore formation rule and the ore finding method of sandstone-type uranium ores, strengthen the research on ore formation geochemistry and ore deposit cause, establish a plurality of ore deposit models, and perform integrated innovation of the ore finding technical method on different types of ore deposits by utilizing the models and matching with the geophysical exploration technology. The innovative idea of the invention is shown in figure 1. The following five control factors are mainly considered in the process of finding ores: the method comprises the following steps of ore body endowing conditions, oxidation zone development conditions, uranium source supply conditions, reducing agent conditions in the stratum and hot fluid superposition transformation conditions. As can be seen from fig. 1, the sandstone-type uranium ore prospecting method based on the "dual-stage and dual-mode" mineralization model of the invention includes four steps of mineralization attribute positioning, mineralization model establishment, target area prediction, and borehole verification:

step two, establishing an ore forming model: establishing a 'dual-stage and dual-mode' mineralization model, including establishing a surface-generated oxidation fluid mineralization model and a thermal fluid superposition transformation mineralization model;

As shown in fig. 1, in the first step, the ore control factors include an ore-adding sand body, an oxidation zone, a uranium source, a reducing agent and a thermal fluid modification, and the first step includes the following processes:

In the second step, firstly, a surface-generated oxidized fluid mineralization model is established

Sandstone-type uranium deposits (abbreviated as SUD) are one of the main directions of ore exploration at home and abroad at present due to the low-cost leaching mining method and the huge resource potential. Interlayer-infiltrated sandstone-type uranium ore (abbreviated as ISSUD) is the most important type of in-situ leached sandstone-type uranium ore, and refers to a uranium ore bed formed by precipitation and enrichment of U6+ converted from U6+ into U4+ by reducing substances (carbon dust, oil gas, pyrite, and the like) in rocks when uranium-containing oxygen-containing fluid (abbreviated as UOF) migrates in sandstone/conglomerate with good water permeability limited by mudstone water barriers at the upper and lower parts. The uranium mineralization effect is mainly due to the fact that a hydrodynamic slope penetrating into the center of the basin is formed by means of extrusion lifting/tilting, under the arid-semiarid climate conditions, oxygen-containing water of atmospheric rainfall leaches uranium source rocks in a supply area or a permeable stratum per se to form uranium-containing oxygen-containing fluid (UOF) capable of migrating in the permeable rocks, and when the UOF meets reducing substances, uranium is reduced from U6+ to U4+ and enriched into a uranium deposit.

Therefore, the establishment of the ore-forming model is helpful for understanding the ore-forming elements and the ore-forming process, and meanwhile, the ore-finding model is established on the basis of the model, so that the aim of finding the ore is finally achieved.

The uranium ore process and control factors formed by sandstone-type uranium ores in the north China under the epigenetic condition have no essential difference from foreign ore deposits, and particularly, local conditions are similar to those of Zhongya in the Tianshan region in the northwest of China. However, the Tianshan mountain main body is in China, and in view of the current topographic and topographic conditions, the Tianshan mountain on the one hand is very high, most areas far exceed the 'secondary mountain making' range, and the Tianshan mountain main body is not beneficial to ore formation; on the other hand, the ascending speed of the Tianshan mountain is high, the oxygen-containing fluid containing uranium quickly enters the basin, and the uranium in the etched source region and the stratum is not extracted or deposited and accumulated in the redox transition zone in enough time, so that the Tianshan mountain is unfavorable for ore formation.

The east region is completely different from the west region, the research area of the project belongs to the middle east region in the north of China, the mountain making effect is mostly caused by stretching, and even under weak extrusion after stretching, the height and the speed of mountain body rising are not as good as those of the Tianshan. In the research area, the elevation difference of the closely related uplift areas of sandstone-type uranium ores, such as Daxingan mountains, Bayno Bao Li Longding and Kennel mountain-salad Zha mountains, is not large, and is favorable for ore formation in the range of 'secondary mountain making'. Of course, the stretching effect in the middle east leads to an increase in heat flow values over a large area, and the magma effect, especially the basal magma effect, is the hot fluid-plus-mineralizing stage after the oxide zone mineralizing. Through years of research, research groups establish sandstone-type uranium ore oxidation zone mineralization models of Baynold Gobi, Bi-lian and Kailu basins.

1. Bayin gobi basin tower lignin deposit mineralization model

The process and pattern of formation of the lignin deposits in the balsa gobi basin are shown in figure 6. As can be seen, the NW direction of the tagnin deposit is the elevation of the pernician-salad roller, and the weathering of a large amount of granite provides a source of both sediment for bartonegobi group deposition and U for the interbed oxidation zone. The lower section of the Bartonegobi group is deposited due to the alluvial fan and the fan delta, and a large amount of debris flow is deposited, so that the porosity of the rock is poor, and the uranium-containing oxygen-containing fluid is difficult to flow in the rock. The deposition system at the upper section of the Bayngola group is mainly a plait-shaped delta, the area close to the material source is a plain phase, the deposition is carried out on a plait-shaped plain diversion river channel, the material granularity is coarse, and the pore permeability is good. The far part is a braided delta front edge phase, and the main sediments are medium and coarse grain sediments with good hole permeability in an underwater diversion river channel, a estuary dam and the like, and a mud-rock interbedded layer in a diversion river channel bay or an delta body bay. The remote source is the front delta, namely lake facies mudstone and marlite deposition. The oxidized zone mineralization process is that uranium-containing oxygen-containing fluid from a source erosion source area firstly flows through a high-permeability plain phase, then continues to flow forwards rapidly along a conglomerate layer of a leading edge phase, and when free oxygen is completely consumed in the flowing process, the U reduction effect occurs, and finally the uranium is enriched into an ore.

2. Two-link basin-type crust-shaped Bayan mineral deposit model

According to the research on the tectonic environment, deposition environment, sand characteristics of target layer and the migration, deposition form and mechanism of uranium, the ore-forming action of Bayan-wula area belongs to the uranium ore-forming under the action of interlayer oxidation zone.

The Bayan Wula area ore-bearing rock stratum is the mudstone separation layer of the upper segment of Saohan group, blue gray, light gray and bright yellow gravel-loose medium and coarse sandstones, and the upper and lower segments of the Yierbutanman group and the Saohan group are the mudstone separation layer. The diagenesis age is 44 +/-5 Ma according to the whole rock U-Pb isochronal method, and the diagenesis age is new ancient times of the new generation (E2). The Bayanwula area shows warm and humid climate, and carbonized plant rhizome and fragment can be seen in gray series sand-glutenite, which provides reducing agent for uranium deposit. Since the third era, basins are always in arid and semiarid states, the formed colors are yellow, brown yellow, red and the like, and the rare colors are grayish green.

From the regional structure, the south-east side of the basin is the sunit bump, and the north-west side is the bayin Baolige bump. A large amount of granite develops on the ridge belts at the two sides, a large amount of volcanic rock fragments are found in the basal stratum, and the rocks are important uranium source bodies of the gulf-river sandstone uranium ores. Since the third era in basins, the pacific plate moved from NW to NWW, while the indian plate had a strong hull collision with the eurasian plate, creating a series of NW-oriented faults. The possibility that oil gas of the lower Tenger group rises to the Saohan group along a fault is high, and the phenomenon that some sandstone cements fluoresce blue is found in part of samples in the Bayanwula area, which shows that oil gas exists in a uranium mineralization area. Because the current uplift area is 400-500 m higher than the basin area, the possible height difference is larger when the ancient times are new, the uranium-containing oxygen-containing fluid on the ancient earth surface seeps downwards along the permeable sand body in the stratum, namely the uranium-containing oxygen-containing interlayer fluid moves towards the center of the basin, and the interlayer fluid can move for a longer distance due to the blocking effect of the upper and lower mudstones of the ore-containing sand body of the Shihan group. After meeting a proper reduction barrier (organic carbon, pyrite or oil gas), the precipitate is enriched into ore. The Bayan wula area ore body is rolled and the lateral interlaminar oxidation mineralization is reflected (figure 7).

3. Kailu basin liverwort-Baolongshan mineral deposit mineralization model

Recent exploration proves that a Qian's shop-Baolongshan mineralization model has a large gap from the knowledge of predecessors. Summer conceivably et al (2003) concluded that the stockhouse deposit was formed by infiltration of uranium-containing oxygen-containing fluid down the skylight of the stockhouse into the yao team sandstone, and that subsequent exploration drilling could confirm that interlaminar-infiltration was unlikely to form near the skylight of the stockhouse, because 1) the yao team sandstone around the skylight was a reduced-color gray, rather than an oxidized color red, yellow, with the stronger the reduced color near the skylight, the stronger the oxidized color away from the skylight; 2) the area of the skylight is not large, and according to incomplete statistics, the exposure of the yao Jia group in the skylight (the fourth line is peeled) is only 17km²On the left and right sides, it is difficult to provide a large amount of uranium sources and water sources for the huge deposit of the Qian shop-Baolongshan; 3) the periphery of the skylight is mostly broken, and even if fluid infiltrates and takes in, most of the parts areFlows along the fracture to both sides, and is difficult to completely permeate in the stratum of the yao team.

Exploration also proves that the Baolongshan-Qian IV ore zone extends far towards the south and the west direction, and the oxidative development strength is better towards the south and the east direction. Therefore, the process of ore formation of uraninite from Kailu basin Diqian shop-Baolongshan sandstone-type uranium deposit can be depicted in FIG. 8, that is, the uranium-containing oxygen-containing fluid from the southwest etched source region permeates into the Yaojia sandstone and flows to the vicinity of the skylight under the action of confined water, and is reduced and gradually enriched into ore under the reduction of carbonized plant debris in the Yaojia sandstone or oil gas rising from the deep part.

In the second step, a thermal fluid superposition reconstruction mineralization model is constructed

An endogenous uranium deposit (often called "hard rock type" uranium deposit in china) is formed by a uranium-containing hydrothermal solution or a hot fluid under appropriate conditions, which has a large number of cases both at home and abroad, such as granite type in south china, volcanic type, even carbo-silicate mudstone type in south west, and the like. However, sandstone-type uranium ores are formed by transformation of hot fluids, and are rarely reported at home and abroad.

The research group finds that uranium mineralization in the middle east and the west of China is different in long-term northern basin sandstone-type uranium ores, uranium mineralization in the west Ili basin and Tuhaa basin are typical interlayer infiltration oxidation zone types, and the mineral formation mode of the middle Asia can be applied. The middle east of China is completely different, the ore deposit has obvious oxidation zone characteristics, but the development rule of the oxidation zone is not a typical middle Asia type interlayer-infiltration type, and meanwhile, a large amount of thermal fluid activity phenomena exist in the ore body, such as hydrothermal surrounding rock alteration, the ore body is controlled by faults to a certain extent, and obvious basal magma activity exists in the ore deposit or near the ore deposit.

1. Uranium mineralization pattern diagram in Bayin Gobi basin tower lignin region

The sandstone-type uranium mineralization of the bartoney gobi basin can be divided into two stages: first-stage oxidative fluid mineralization: after sliding and pulling separation, a weak extrusion environment appears in the basin, and the mineralization fluid is surface-generated uranium-containing oxygen-containing fluid. The specific formation process is that the NW direction of the tamarind deposit is a Zongni-salad-prick mountain elevation area, and the weathering of a large amount of granite provides a sediment source for the deposition of the Bartoney gobi group and a U source for the interlaminar oxidation zone. The lower section of the Bartonegobi group is deposited due to the alluvial fan and the fan delta, and a large amount of debris flow is deposited, so that the porosity of the rock is poor, and the uranium-containing oxygen-containing fluid is difficult to flow in the rock. The deposition system at the upper section of the Bayngola group is mainly a plait-shaped delta, the area close to the material source is a plain phase, the deposition is carried out on a plait-shaped plain diversion river channel, the material granularity is coarse, and the pore permeability is good. The far part is a braided delta front edge phase, and the main sediments are medium and coarse grain sediments with good hole permeability in an underwater diversion river channel, a estuary dam and the like, and a mud-rock interbedded layer in a diversion river channel bay or an delta body bay. The remote source is the front delta, namely lake facies mudstone and marlite deposition. The oxidation zone mineralization process is that the uranium containing oxygen bearing fluid from the source erosion zone first flows through the highly permeable plain phase and then continues to flow rapidly forward along the glutenite layer of the leading edge phase, but when the free oxygen is completely depleted during the flow process, U reduction occurs, see fig. 9.

And (3) second-stage hot fluid superposition transformation mineralization: after sliding extrusion, the basin is stretched in a sliding way, and large-scale basal rock slurry eruption is performed, so that the exposed basalt is formed. The action of hot fluid is carried out after the magma movement, hot fluid transformation is superposed after the oxidized zone is mineralized, the early mineralization is further subjected to transformation and enrichment, and a large amount of metal sulfides are generated. Regional background conditions studies have shown that during the early chalky period of the bartonella basin, tectonic-magmatic conditions are present in the region, since the formation of the periench pattern occurs shortly after the deposition of the bartonella group, during which a large number of magma eruptions occur, which causes a temperature rise throughout the basin, frequent diagenesis, mineralisation, which is immediately modified by subsequent thermal fluids after the oxidation of the strata into mineral, which makes it possible to find evidence not only from the formation of large amounts of metal sulphides, carbonate cements and the veinous filling of the mineralisation.

2 two-connected-basin underground Hadao diagram deposit mineralization model

The mineralization of the Hadada plot area of the two-connected basin field can also be divided into two stages and two modes. Research shows that on one hand, Hada diagram ore deposit formation and uranium-containing oxygen-containing fluid migrate and oxidize from the center of an ancient river channel to two sides, the migration speed of the fluid is slowed down by the retardation of waste river channel sediments at two sides, and uranium is adsorbed and reduced by clay and carbon dust to be enriched; on the other hand, since the new generation, the strong fracture structure and the magma movement of the bicuspid basin NW cause the strong eruption of the Abaga basalt magma, and the transformation of the shallow geologic body by the deep hot fluid is brought. During the NW direction construction activity along the Cunning-dipyridamole route, substances such as deep hot fluid are likely to rise to a shallow part, the stack reconstruction is carried out on uranium mineralization in a Hada map area, the formation of giant crystal pyrite and the appearance of a large amount of hydrothermal alteration minerals are likely to be related to the later hot fluid stack reconstruction, and the relationship between mineralization and structure is also verified by the characteristics of the distribution of the Hada map uranium mineralizers along the NW direction. Cause of sandstone-type uranium deposit: macroscopically, the uranium mineralization range is penetrated by a large number of carbonate veins and iron veins; microscopically, sandstone lattice particles are dissolved in ores, and alteration minerals such as calcite and sericite and low-temperature metal minerals such as chalcopyrite and native copper are closely symbiotic with asphalt uranite and uranite, which are products of the superposition transformation effect of hot fluid.

In combination, uranium mineralization in Hadada regions is particularly relevant, see FIG. 10. Besides being suspended in an oxidation zone, uranium mineralization is distributed in a band shape on a plane, and mineralization grades formed after superposition transformation are rich and have larger reserves, and are temporarily called as mineralization of a Hada pattern.

3. Ore model diagram for transformation of new-generation hot fluid in Kailu basin

The formation of uranium deposits in the kailu basin marchantia-baolongshan uranium store can also be divided into two stages: namely a surface-grown uranium-containing oxygen-containing fluid mineralization stage and a thermal fluid transformation mineralization stage.

First stage-infiltration between layers and oxidation to form ore. In the deposition period of the yao team, the primary grey sandstone of the yao team is formed under the arid-semiarid environment and the relatively humid environment locally. A large amount of plant debris and mudstone interlayers locally contained in the sedimentation process can adsorb a certain amount of uranium in the sedimentation-diagenesis period to cause the local pre-enrichment of uranium, and the mineralization foundation is laid for uranium-containing oxygen-containing fluid infiltrated in the later period. The true oxidation zone mineralization is accompanied by strong tectonic reversal in the course of the movement of the tender river in late chalkiness, causing the yao team to lift and denude, expose the surface at the edge of the basin and receive the infiltration of uranium-containing oxygen-containing fluid. Meanwhile, local uplift occurs near the Qianjiao, and the Yaojia group is also corroded and exposed to form a skylight. The skylight may serve as the ultimate source of drainage for the southwest mound area infiltration fluid, and therefore, the uranium-containing oxygen-containing fluid from the southwest mound area of the source basin flows continuously to the clerestory skylight of the store, and therefore, a large interlayer oxidation zone is formed between the southwest mound area and the clerestory skylight of the store. In the area not far from the southern area of the Qian Shi-Bao Longshan, or along the sides of the plait-like tract of the Yao in the basin, oxidation-reduction transition zones appeared, forming extensive uranium mineralization, see FIG. 11.

And in the second stage, hot fluid superposition is transformed into ore. Numerous studies have shown that the massive basal magma activity in the kailu basin has a great influence on early uranium mineralization, of which the hydrothermal activity of the magma in the Bartonian phase (about 40 ± Ma) of the ancient epoch. Firstly, a stable diabase layer can be seen in a large number of drill cores in places such as Baolongshan, Qianjiao and the like, and is inserted into the upper section of a yao group and a tender river group, sandstone at the edge is baked by the invasion action of the diabase, and purple sandstone is changed into dark purple under the action of heat, the rock is compact and hard and is cemented by calcium, a large number of calcite and iron-containing dolomite are seen, and a gas-liquid inclusion can be seen in the calcite, so that a low-temperature hot fluid environment is reflected; secondly, analysis results of major elements, trace elements and rare earth elements of the rocks also show that the rocks containing U have certain correlation with low-temperature elements, light rare earth enrichment and the like, which indicates that the target layer containing ores in the research area is influenced more generally by later-stage thermal activity modification; and thirdly, a uranium occurrence state result developed by using an electronic probe shows that the uraninite vein body can be seen in the Baixing spitting area, most of the uraninite is a low-temperature mineralization product, and the distribution rule has certain correlation with the rephrased diabase vein body. Comprehensive analysis shows that diabrotica veins clamped by F2 and F3 fracture are formed, so that a local section forms 'uranite veins' formed by coprecipitation of uranite and pyrite with low-temperature hydrothermal characteristics, a thermal event is shifted, namely, a primary uranium mineralization effect in a primary region and a secondary superposition enrichment mineralization effect on an earlier oxidation zone mineralization effect are achieved, the reformed and superposed uranium ore body also has the tendency of thickening and enlarging in a fracture development region, and a pattern diagram is shown in figure 11.

4. Nigeralgard basin Arzik uranium metallogenic model diagram

In the region of Armadia nigricans, Nigerl, Baggeda, Arzerk, Negeria, is in long-term weathering denudation at late Jurasia, and at the same time, NW-SE stretching occurs in late Jurasia, forming the overall pattern of Longyu-Luo in the Arzerk region, and controlling the deposition of chalk and later stages. In early chalky (assaiwu period), lake invasion gradually expands from west to east, a shallow lake phase environment is formed in the back inclined zone of the assaiuk, and a set of sorted and ground grave-containing sandstone and coarse sandstone, namely the ore-containing target layer of the assaiwu group, is deposited. Subsequently, in the itazier period, the lake invasion action continues to expand towards western alllite regions, and thick-layered deep lake-semi-deep lake facies mudstone-sandwiched thin-layer fine sandstone is formed in the teginda region. The Arsatura gravel group is below the Arsatura gravel group, and the Ilavier thick-layer mudstone group is above the Arsatura gravel group, and the spatial combination relationship forms the perfect combination of the ore-containing space and the storage condition in the research area. Until late chalkiness, the area was subjected to a pressure-torsion tectonic activity, forming a soothing intralamellar flexure in the jagma group, accompanied by a local, larger-scale fluid activity, hot fluid from deep, rising along the fractured structure, during which the fluid extracted uranium in the dwarfs and its previous strata, when reaching the illizel group thick-layer mudstone at the top of the assaia group, the vertical migration path of the fluid was interrupted due to the closure of the fault in the mudstone, at which time the fluid could migrate laterally only along the well-perforated sand of the assaia group. The uranium-containing hot fluid is subjected to reduction in a section where the fluid passes under the action of oil gas and low-valent iron. Under the alkaline condition, the uranyl complex is precipitated,accompanied by the formation of analcite and carbonate minerals and sericite. In this process, feldspar and quartz are dissolved. Na-Al-Si dissociated from feldspar enters analcime, part of K enters sericite, part of Si dissolved from quartz is increased in secondary level, and the other part enters uranite. Carbonate ion and Ca in formation of uraninite and uranite by uranyl carbonate complex²⁺And Mg²⁺Combining to produce calcite and dolomite. Fig. 12 illustrates uranium mineralization patterns formed by the study area under the influence of the formation and hot fluid.

In the second step of the invention, a double mineralization theory of oxidation before reformation is provided: breaking the single epibiotic oxidation fluid induced ore of the basin sandstone-type uranium ore, and establishing a thermal fluid ore forming model at the later stage of the stacking of the epibiotic oxidation ore forming.

Traditionally, sandstone-type uranium, also called water-induced uranium deposit, is a non-hydrothermal mineral caused by reduction barrier precipitation of an epibiotic oxidizing fluid in a permeable layer permeation process. The project group discovers that uranium minerals in ore deposits are associated with a large amount of low-temperature hydrothermal minerals in the research of sandstone-type uranium ores carried out in eastern basins in northern China, and in fig. 13, asphalt uranium ores (Pitch) of the ore deposits of an A-bi-basin Hadada diagram are filled in quartz (Qz) particle net vein-shaped cracked cracks; b-bi-pan-connected Hadada deposit uranite (Pitch), Sphalerite (Sphalerite) and pyrite (Py) are symbiotically grown in pores and cracks; calcite (Cal) strongly substitutes quartz (Qz) particles in C-Kailu basin Baixing vomiting deposit; D-Kailu basin Baixing spitting deposit titanium uranium ore (Bra) and Sphalerite (Sphalerite) pulse filling; pyrite (Py) and bornite (Bor) in the shale fracture of E-Bayin Gobi basin tower lignin deposit, gypsum (Gp); selenium-copper-nickel ore (Pen), selenium-copper basket (Klo) and selenium-lead ore (Cla) are symbiotic in F-Bayin Goniobia basin tower lignin ore deposit sandstone. Research shows that uranium mineralization is related to later-stage hot fluid transformation, after the basin is deposited, the basin is reversely lifted to form surface-generated oxidized fluid mineralization, the basin stretches again to cause fractured magma movement, and the deep hot fluid rises to superpose and transform the surface-generated fluid mineralization, namely, the dual mineralization effects of oxidation and transformation are achieved, so that the size of an ore body is enlarged, and the shape and the space position of the ore body are changed.

In the second step of the invention, the dual ore control understanding of 'extrusion before extension' is provided: breaks through the single 'secondary mountain making' slope-lifting ore control function of basin sandstone-type uranium ores, and provides a new understanding of multi-stage 'extrusion-extension' structure superposition ore control.

The scholars believe that the 'secondary hilling' action causes the ore-bearing target layer to be lifted and degraded, and the oxygen-bearing uranium-bearing fluid permeates into the target layer to form ore in the oxidation-reduction transition zone (namely the front sharp line). However, the east basin in the north of China forms an ore-containing target layer (fig. 14A) under the extended background, so that an ore containing space is provided for later-stage uranium gathering and ore forming; late chalkiness-early ancient squeezing, leading to "lift-off" of the target layer, infiltration of the epinastic uranium-bearing oxygenated fluid into the mineral formation (fig. 14B); since late in the ancient age, the basin stretched again and the thermostructural events caused hot fluid upwelling superimposed mineralizing (fig. 14C). On the basis, a new 'two-stage' model is established, wherein an ore storage target layer is formed under the extrusion background, and an oxidation ore forming and hot fluid superposition ore forming are performed under the stretching background.

In the second step of the invention, the invention establishes a 'two-stage and double-mode' ore-forming theory and establishes a 'two-stage and double-mode' ore-forming model of oxidation ore-forming under the regional extrusion background and thermal fluid superposition under the large-scale stretching background.

A two-stage and two-mode ore forming model of uranium deposit in eastern basin in northern China: in the basin such as the second connection, the beginning of the river, the wall of the Gobi and the like, under the background of the early chalkiness and the late chalkiness, the mineral-containing target layer mainly comprising braided river and braided Delta sands is formed.

The first stage, the stage of interlayer infiltration oxidation mineralization. The squeezing action of late chalkiness, early in the past, is accompanied by a strong inversion of formation, causing the target layer to lift and degrade, exposing the surface at the edge of the basin, and receiving the infiltration of uranium-containing oxygenated fluids. The uranium-containing oxygen-containing fluid from the uranium source area continuously flows and is discharged in the permeable layer, and uranium is reduced, adsorbed and enriched in the redox transition zone to form a roll-shaped uranium ore body (figure 15A).

And the second stage is a hot fluid superposition reconstruction mineralization stage. Since late in the past, basins are stretched again, the construction activity is strong, large-scale basal magma activity exists in each basin, the fluid rises along the fracture along with the hot fluid, the fluid interacts with the ore-containing layer, a large amount of hydrothermally altered minerals appear, meanwhile, the original uranium ore body is strongly superposed and modified, and the shape of the ore body is modified into a plate shape or a lens shape from a roll shape (fig. 15B).

In the third step, a radioactive ore prospecting technology, a ground high-precision gravity ore prospecting technology and a CSAMT ore prospecting technology are adopted. The radioactive exploration method can be used for directly finding uranium ores and also can be used for finding fracture structures. The radioactive abnormity and fracture of the ore exploration area can be realized rapidly through the vehicle-mounted gamma energy spectrum, and the soil thermoluminescence has the advantage of locally searching the radioactive abnormity with a certain depth. The ground high-precision gravity prospecting technology can be used for detecting the buried depth of the substrate and identifying the fracture. Controlled source audio electromagnetic sounding (CSAMT) can be used to identify substrate burial depth, fractures, initially trace the formation, and demarcate dephasing.

Different types of sandstone type uranium deposit prospecting modes include: the braided river sandstone type uranium ore prospecting mode (model + "+ CSAMT + sedimentary microfacies + ground high-precision gravity + soil thermoluminescence) exists in braided river sandstone. Therefore, it is important to track the spatial distribution of braided river sandstones. The braided river is obviously controlled by the concave-convex terrain of the substrate, so that the ground high-precision gravity prospecting technology is used; interpreting braided river sedimentary facies and related microfacies by combining CSAMT, and tracking the spatial distribution of the microfacies; and (3) searching radioactive anomalies in the braided river sand body by utilizing soil thermoluminescence so as to position the uranium ore. CSAMT determines the distribution range of river channels and sand bodies, deposits microphase analysis to define the range of ore-containing sand bodies, and determines the high-precision gravity interpretation fracture and sand bodies on the ground, and determines the hot fluid channel, and the double-peak one-low state of soil thermoluminescence directly determines the ore bodies.

The uranium mine in the shallow burial shore shallow lake sandstone type uranium mine prospecting mode (model + "+ vehicle-mounted gamma energy spectrum + structure interpretation + sedimentary microfacies) is identified in shallowly buried mudstone, and the mudstone in the shore shallow lake sandstone is generally present in a large area. In addition, uranium mineralization in this mode is related to fracture structure. Therefore, under the guidance of the model, the drill core is used for researching sedimentary microfacies, and the vehicle-mounted gamma energy spectrum is used for interpreting fracture structures and positioning uranium ores. The vehicle-mounted gamma energy spectrum defines the abnormal range of regional uranium, deposits microphase identification ore control sand bodies, judges the regional distribution range of the uranium ore bodies according to the structure pattern of the hump and valley, determines the ore control structure and a fluid channel by remote sensing fracture interpretation, and comprehensively judges the distribution range of the ore bodies.

The uranium mine exploration mode of the braided delta sandstone type uranium mine (the model + "+ uranium source + sedimentary microfacies + ground high-precision gravity) exists in braided river delta sandstone, the burial depth is shallow, and the mode is obviously controlled by slope topography. Braided river delta sandstone is generally closer to uranium sources. Therefore, the uranium source needs to be researched by a geological sampling analysis method. The braided delta phase sedimentary change existing in the mode uranium mine is large, sedimentary microphase needs to be analyzed through a drill core, and in addition, the slope terrain is found through ground high-precision gravity measurement. The braided delta is adjacent to an erosion source area, abundant uranium sources of the erosion source area are the premise of finding ores, shallow seismic interpretation is carried out to judge sand bodies of ore-containing target layers, deposition microphase interpretation is carried out to define finger-shaped staggered sand mud positions, ground high-precision gravity interpretation is carried out to judge the front edge fracture of the braided delta, a hot fluid channel is judged, and the distribution range of the ore bodies is determined.

The ore finding effect verification is carried out in the Hadamard map area of the two-link basin by using the braided river sandstone ore finding mode, and a large ore deposit is preliminarily controlled at present; uranium resource exploration is carried out in the great forest-double treasure area of the Kailu basin by utilizing the mode of searching for uranium ores in the braided river sandstone type, and an ultra-large ore-forming zone is controlled at present; a first-level mineral-forming prospect is predicted in an Arzerk area of a Nigerland Adaderz basin by utilizing a shallow burial shore shallow lake sandstone ore prospecting mode, drilling verification is carried out in the prospect, and the effect is remarkable.

Radioactive exploration and exploration technology

Radon is a gaseous radionuclide directly released from uranium ore bodies and has strong migration capacity, so the radon and daughter measurement method is an effective method for deeply attacking and finding blind ores, and the measurement methods are many. In northern arid basin areas, surface media are loose, the gas retention condition is not good, and the traditional ground radioactive detection method is difficult to capture the ore body abnormity. The result of the project group passing the indoor simulation and the mine area test shows that the project group is sensitiveHigh-degree and anti-interference natural soil thermoluminescence method and²¹⁰the Po method can achieve a good application effect, research groups study and clarify the migration mechanism of nano-scale metal elements under sandstone-type uranium ore geological geochemical conditions, and data information obtained is fully excavated and hidden by using weak earth surface anomaly extraction technologies such as genetic algorithm optimized segmentation, structural autocovariance and cross covariance calculation, fuzzy clustering analysis and the like. An artificial neuron network method and a method for inversion of uranium ore body burial depth by using surface radon and daughter measurement abnormity are researched, a method for predicting ore bed burial depth and ore bed boundary is researched and explored, and the effectiveness and reliability of the method are verified through field tests.

Research groups have conducted researches on radioactive method exploration of sandstone-type uranium deposit in a plurality of basins in the north. Sinkiang 511 and 512 deposits are produced in the river-Delta system sandstone of the Ili basin and belong to the type of rolled or interlaminar oxidation zone. It is generally believed that the mineralizing material is from granite or other rock around the basin where the geochemical abundance of uranium is relatively high, and is degraded by weathering, where U⁴⁺Oxidation of uranium to U⁶⁺The uranyl ions enter the groundwater and then slowly flow along the permeable sandstone layer body, and are reduced into U when encountering oxidation-reduction geochemical barrier⁴⁺And precipitation occurs. Mineralization is closely related to the interbed oxidation zone, two geochemical zones of oxidation and reduction are generated in the rock stratum, and uranium is precipitated on a dynamic oxidation-reduction interface.

Fig. 2 shows the results of natural thermoluminescence measurements of soil from section 48 of a uranium 511 deposit. It can be seen from the figure that the natural thermoluminescent high abnormal jump of the soil is located at both ends of the ore body, and the position of the ore body corresponds to the measured low value region. The characteristic is different from the abnormal distribution pattern of the uranium granite ore, which is related to the specific output environment and formation mode of the uranium sandstone-type ore, such as the ore body is produced in the slowly-inclined sandstone with a compact water-resisting layer on the upper and lower sides; in the process of forming ore, the oxidation-reduction front is pushed forward along the tendency of a sand layer, and a trace is left; the time to mine is late (mid-to-new world) until now it is slow to go on. Moreover, the existence of a compact water-proof layer above the ore body is not favorable for the ore depositThe radon gas migrates upwards, thereby forming the special thermoluminescent abnormal characteristic of low measured value above the ore body and high measured value at the periphery of the ore body on the placeable sandstone-type uranium deposit. From this, the concentration N of radon and its daughter can be seen_HRelated to the burial depth h of the ore body and providing theoretical basis for the inversion explanation of radon anomaly.

Figure 3 shows the results of the measurement of the typical soil Thermoluminescence (TL) and natural potential (Eh) on the dyad of diben-bayan sandstone uranium ore. As seen from the figure, TL measurement curve at the position of the ore body has obvious 'double-peak' abnormity, and Eh measurement curve has obvious gradient steep change section. This feature is a smooth, continuous measurement of the level of underground uranium ore production. The local uranium ore body's of producing form level, when the ore body is discontinuous, because two-layer uranium ore body about the discontinuous and partial section of uranium ore body appears, consequently its actual measurement curve's form is complicated relatively, nevertheless corresponds to each section uranium ore body, still satisfies "doublet" unusual characteristic, only partial measurement station makes the measurement curve can appear the next extreme phenomenon in the ore body top owing to the influence stack of two-layer uranium ore body about the influence of upper and lower layer uranium ore body together, can not produce great influence to the abnormal interpretation.

In addition, in the course of research, it was found that, in addition to the above-mentioned situation, some section TL measurement curves have the abnormal feature of "two high values are sandwiched between one low value", but the positions of the high value abnormality and the low value abnormality are shifted, and even the industrial hole is corresponding to the high value abnormality (as shown in fig. 4). It can be seen that the attitude of the underground uranium ore body on these sections is inclined, and the larger the inclination angle, the more the abnormal positional deviation is experienced. Meanwhile, the gradient steep change band of the Eh measurement curve on the section plane is also shifted. The abnormal characteristic phenomenon on the sandstone uranium ore body is consistent with the Eh abnormal curve influenced by the occurrence of the underground uranium ore body discovered by a project group in forward research of a natural electric field, which shows that the migration of radon and daughters thereof is in a certain relation with the natural electric field of the sandstone uranium ore body, and the reason is that the radon and the daughters thereof have positive charges and change the distribution under the influence of the underground oxidation-reduction electric field of the sandstone uranium ore body.

Ground high-precision gravity prospecting technology

The ancient river sandstone type is the most important type of the two-basin and two-basin connection, and for uranium mineralization development in the ancient river sand, a research group initiatively utilizes a ground high-precision gravity measurement (figure 5) and an inversion method to prepare and position the position and the depth of a river, and simultaneously invert the development conditions of the sand and a nearby fault, so that a basis is provided for finding uranium ore bodies in the river and explaining the formation of the uranium mineralization.

The work comprises data processing and interpretation of a plurality of gravity profiles, the interpretation method comprises a wave number domain derivative iteration method, a field separation iteration filtering method and a cross-correlation imaging technology based on residual anomaly applied to the gravity data, and a better processing result is obtained. Meanwhile, according to the results of gravity anomaly derivative analysis, TASD and Euler deconvolution inversion, the fracture positions and the fracture shapes of the gravity profiles are inverted, and 5 fractures on the NL profile, 6 fractures on the MD profile, 9 fractures on the E400 line and 4 fractures on the SH line are obtained. In addition, a geological-geophysical model with a plurality of sections is established by taking gravity data as a basis and combining geological data, drilling data and electrical data of a research area; the division of the secondary building units was performed, indicating that the gridler-and-die recesses of NL and MD sections both exhibit significant channel sedimentation characteristics, which provides geophysical evidence for the existence of ancient channels.

CSAMT prospecting technique

The cover layer structure of the two connected basins is formed by gradual inherited development and transformation changes of two different stress field environments of tension trap and differential lifting on the basis of a base structure, and is divided into a basin forming structure during early chalk trap lake basin deposition and more obvious three lifting events since the late stage of early chalk. In the vertical direction, the basin is mainly formed by stacking three structural layers with different structural characteristics: 1) a basin basement rock system formed by the anterior and the middle generations; 2) the early white chalky Bazhi group Alzhen group and Tenggel group as the main body to form the subsidence cover layer of the sunken lake; 3) the bottom part of the river sediment of the tourette system Bayan population. The original rock is subjected to stress transformation of fold activity and influence of later geological action, the syncline is usually high in resistivity, and the anticline is relatively low; the fracture structure is mainly characterized by low resistance due to the relatively broken rock and relatively high water content.

The basement of the Erlian basin is composed of metamorphic rocks of the original and ancient communities and magmatic rocks mainly in West-Wallace and Jia Li east China. The main lithology is granite, andesite, FeiOu fine porphyry and the like, and the widely distributed igneous rock is an important source of the duplex sandstone type uranium ore. The substrate has higher resistivity, igneous rock can reach 4000 ohm-m, sedimentary rock n multiplied by 10²～ n×10³Omega.m. The filling sequence of the lower part of the basin is Jurassic group, such as Alatan synthetic group and Xingan Ling group. Wherein the alatan resultant force group is a set of river facies, coastal shallow lake facies and lake and marsh facies deposition, and lithological combination is represented by a coal-containing lithologic series with a thick lower part and a thin upper part. The Xingan mountain group is a set of volcanic lava with volcaniclastic rocks and river facies sedimentary rocks. From the well logging data and the sample test analysis, the resistivity of the Alatan's resultant force group is n multiplied by 10²～n×10³Omega.m; khingan group resistivity n x 10²～n×10³Ω·m。

The middle filling sequence is the Altai group and the Tenger group at the middle and lower parts of the early chalk system. Wherein Altai group is a set of lime green, red brown conglomerate, conglomerate containing sandstone, included lime green, ash, dark grey mudstone and carbonate rock, and tuff conglomerate, basalt. The Tenger group is divided into a Teng first section and a Teng second section from bottom to top by combination of lithology and fossil. The first section is dark deep lake mudstone and turbid rock. The upper part of the crude oil-containing layer system becomes coarse, and the crude oil-containing layer system mainly comprises sandstone, conglomerate and thinner mudstone. The rising section mainly comprises three layers of sandstone, conglomerate and dark grey mudstone, the lower part is relatively thick and thin upwards, and the rising section contains dolomitic mudstone. Mainly comprises a fan delta, a braided river delta and lake-phase argillaceous sediments, the bottom boundary is limited by local non-integration, and the top is a secondary oil-containing system covered on a Seaharala group and is thick oil. From the analysis of the well log data, the Algorian resistivity n x 10²～n×10³Ω · m,; tenger group resistivity n x 10²～n×10³Ω·m。

The top filling sequences were seohan, bigeminal and neonatal deposition. The Chalker phylum group is a set of coarse debris coal-bearing rock systems. The lower part is gray siltstone and gluteniteMud rock is clamped, and the middle green and gray mud rock is clamped with deep ash, gray black carbon mud rock and a mined lignite bed; the upper part is gray green, and the gray sandstone is sandwiched with gray green, purple red and brownish red mudstone. The group is mainly a set of river and marsh phase deposits, generally containing coal wires, and is an important coal-forming period of Bayanhua group. The second group of the chalky system is built by variegated clastic rocks deposited by a set of rivers, lakes and alluvial fans, and the lithology is brick red, lime green and earthy yellow iron-manganese-containing siltstones, sandstones, conglomerates with mudstones and silty mudstones. The stratum of the third line is relatively complete in development and is a set of filling materials of river and local lake sedimentation systems. The fourth system mainly comprises aeolian sand, lake beds and basalt. "n x 10" of the contestant group²～n×10³Omega m, two connected groups n x 10²～n×10³Omega. m, new generation deposition n.times.10²～n×10³Omega m, third series stratum n x 10²～n×10³Omega m, fourth series strata n x 10²～n×10³Ω·m。

According to the analysis, the geological units and the structures in the research area have obvious resistivity difference, and the basin foundation, the structures and the stratums can be divided by applying the controllable source audio magnetotelluric method. CSAMT inversion results can better reflect the rising and sinking relation of the research area, and can distinguish the sand content proportion in the sediment layer to a certain extent.

Claims

1. A sandstone-type uranium ore prospecting method based on a 'dual-stage and dual-mode' mineralization model is characterized by comprising four steps of mineralization attribute positioning, mineralization model establishment, target area prediction and drilling verification:

a 'two-stage double-mode' ore formation theory is established, and a 'two-stage double-mode' ore formation model of oxidation ore formation under the regional extrusion background and thermal fluid superposition under the large-scale stretching background is established; a basin uranium deposit 'dual-stage and dual-mode' mineralization model is as follows: the basin forms an ore-containing target layer mainly comprising braided rivers and braided delta sands under the background of early chalkiness and late chalkiness;

first stage-interbed infiltration oxidation mineralization stage: the squeezing action in late chalkiness-early ancient times is accompanied by strong structural reversal, causing the target layer to lift and degrade, exposing the surface at the edge of the basin and receiving the infiltration of uranium-containing oxygen-containing fluids; uranium-containing oxygen-containing fluid from a uranium source region continuously flows and is discharged in a permeable layer, and uranium is reduced, adsorbed and enriched in an oxidation-reduction transition zone to form a rolled uranium ore body;

the second stage is a hot fluid superposition transformation mineralization stage: since late ages, basins are stretched again, the construction activity is strong, each basin has large-scale basic magma activity, the fluid rises along the fracture along with the hot fluid, the fluid interacts with the ore-bearing layer, a large amount of hydrothermally altered minerals appear, meanwhile, the original uranium ore body is strongly overlapped and modified, and the shape of the ore body is modified into a plate shape or a lens shape from a roll shape;

2. The ore prospecting method for the sandstone-type uranium ore based on the 'two-stage and dual-mode' ore forming model according to claim 1, wherein in the first step, ore control factors comprise ore-forming sand, an oxidation zone, a uranium source, a reducing agent and hot fluid transformation, and the first step comprises the following processes:

(1) the method comprises the following steps of (1) evaluating the space-time distribution characteristics of a sand body storage space through a geophysical method, well logging curve analysis and sedimentary facies and microphase research of a target stratum sand body, and realizing storage space positioning;

(3) the uranium source is a basic condition formed by sandstone-type uranium deposit, and the abundance degree of the uranium source is judged by analyzing and researching the uranium content of an etched source region, a hidden etched source region and the uranium content of a sand body through field geological survey sampling of the etched source region, so that the mineralization potential is evaluated, and the material condition positioning is realized;

(4) the mineralizing effect of the reductant-uranium is U⁶⁺Is converted into U⁴⁺Therefore, the amount and type of reducing agent in the stratum has influence on the mineralized uranium; researching the change of the paleoclimate, tracking the development condition of carbon dust in the stratum, the existence of low-valence sulfides and the existence of pyrite and marcasite, and researching whether oil gas enters a target layer or not to realize the location of reduction enrichment;

(5) the hot fluid transformation, namely researching the conditions of hot fluid development, comprises deep fracture and basal magma movement, marks left by hot fluid-rock interaction, crustal extension crack action and increase of heat flow values in a large area and basin range, creates conditions for the superposition transformation of early mineralization by hot fluid, and realizes transformation positioning.

3. The ore exploration method for sandstone-type uranium ores based on the dual-stage and dual-mode ore forming model according to claim 1, wherein in the second step, a dual-ore forming theory of oxidation before modification is provided: breaking single epibiotic oxidation fluid induced ore of basin sandstone type uranium ore, and establishing a thermal fluid ore forming model at the later stage of epibiotic oxidation ore forming superposition; uranium mineralization is relevant with later stage hot fluid transformation, and after basin deposit reversal lifting formed surface oxidation fluid mineralization, basin stretches once more and leads to fracture magma activity, and deep hot fluid rises and adds the transformation mineralization to surface formation ore, and two mineralization effects of "transformation after oxidation" have promptly enlarged the ore body scale, have changed ore body form and spatial position.

4. The ore exploration method for the sandstone-type uranium ore based on the dual-stage and dual-mode ore forming model according to claim 1, wherein in the second step, a dual-ore control understanding of extrusion before expansion is provided: breaks through the single 'secondary mountain making' slope-lifting ore control function of basin sandstone-type uranium ores, and provides a new understanding of multi-phase 'extrusion-extension' structure superposition ore control; forming an ore-containing target layer in the basin under the extending background, and providing an ore containing space for later-stage uranium gathering and ore forming; the extrusion effect in late chalkiness-early ancient period leads to the 'tilting' of the target layer and the infiltration of the oxygen-containing fluid containing uranium on the surface into the ore; since the late ancient time, the basin stretches again, and the thermal tectonic event causes the hot fluid to upwelle and overlap to cause the ore; on the basis, a layer forming an ore storage mesh under an extrusion background is established, and an oxidation ore-forming and hot fluid superposition ore-forming 'two-stage' ore-forming model under an extension background is established.

5. The method for prospecting the sandstone-type uranium ore based on the two-stage and dual-mode mineralization model according to claim 1, wherein a radioactive prospecting technology, a ground high-precision gravity prospecting technology and a CSAMT prospecting technology are adopted in the third step; different types of sandstone type uranium deposit prospecting modes include: the ore searching mode of the braided river sandstone type uranium ore is 'model +' + CSAMT + sedimentary microfacies + ground high-precision gravity + soil thermoluminescence; the ore searching mode of shallow burial shore shallow lake sandstone type uranium ore is 'model +' + vehicle-mounted gamma energy spectrum + structure interpretation + sedimentary microfacies; the ore searching mode of the braided delta sandstone type uranium ore is 'model +' + uranium source + sedimentary microfacies + ground high-precision gravity.