New-type barite deposit metallogenic mode construction method based on co-sedimentary fault

Abstract

The invention discloses a new-type barite deposit mineralization mode construction method based on a same sedimentary fault. The method belongs to the field of geological exploration and mineral resource prediction, and comprises the following steps: analyzing the earth crust cracking activity history of an earthquake-Hangjian broken basin, and recovering a basin'checkerboard 'structure prototype; by means of field geological survey and research, drilling engineering, geophysics, remote sensing geological big data and the like, north-east-east-direction and north-west-direction co-sedimentary fault networks are identified and modeled, and a deep metallogenic fluid rising and jet flow channel is determined; the metallogenic process is concluded into a hydrothermal jet flow stage and an underwater gravity flow deposition stage, deep fluid is revealed to rise, jet flow and precipitate along a fault, and an ore-rich zone of a composite seabed fan body group is formed; and a geochemical prospecting prediction model combining trace element and sulfur isotope characteristics is established. The method systematically clarifies a coupling mechanism of ore control of the same sedimentary fault, ore-forming fluid migration and gravity flow deposition, and provides a theoretical basis and a technical means for prospecting prediction of the barite deposit in the Hendan-Hangjian fault basin.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration and mineral resource prediction, and more specifically relates to a method for constructing a new type of barite deposit metallogenic model based on syn-sedimentary faults. Background Technology

[0002] Barite is an important non-metallic mineral resource, widely used in petroleum, chemical, building materials, and pharmaceutical industries. In recent years, with increasing industrial demand and intensified resource consumption, the exploration and development of barite has received increasing attention. Traditional barite prospecting methods mainly rely on geological mapping, geophysical and geochemical anomaly tracking, and drilling verification. These methods can discover and delineate barite ore bodies to a certain extent, but they suffer from low prospecting efficiency, limited prediction accuracy, and a lack of in-depth understanding of the ore formation mechanism.

[0003] With the continuous development of geochemical theories and technologies, the prediction of mineral deposits using geochemical parameters and isotopic characteristics has become a research hotspot. Especially in rift basins and deep-water black rock systems, the mineralization process of barite deposits is controlled by multiple factors, including multi-stage tectonic activity, syn-sedimentary faults, and deep fluid migration, exhibiting strong stratabound and tectonic ore-controlling characteristics. Furthermore, the characteristics of trace elements (such as V, Mo, U, Cu, Zn, etc.) and their combinations enriched in the ore-bearing rock system, the Co / Ni ratio, and sulfur isotopes (δ¹⁰ and δ¹⁰) are also important factors. 34 The distribution patterns of S) have become important geochemical prospecting indicators for indicating the metallogenic environment and predicting the distribution of ore bodies.

[0004] However, existing technologies have not yet systematically integrated diverse information such as syn-sedimentary fault structures, fluid migration channels, exhalative sedimentary mineralization, and geochemical indicators, and lack quantitative models for the mineralization mechanism and spatial distribution patterns of barite deposits. There is an urgent need for a comprehensive mineralization prediction method that combines geological structures, sedimentary characteristics, and geochemical parameters to improve the prospecting efficiency and theoretical guidance level of stratabound deposits such as barite. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of existing barite deposit prospecting methods, such as low prospecting efficiency, insufficient prediction accuracy, and a lack of in-depth understanding of mineralization mechanisms and the spatial distribution of ore bodies. This invention provides a method for constructing barite deposit metallogenic models and predicting mineralization by combining geological structures, sedimentary environments, and geochemical parameters, so as to achieve efficient and accurate prediction of barite deposits and in-depth revelation of their mineralization laws.

[0006] To achieve the above objectives, the present invention employs the following technical solution: the method comprises the following steps: (1) Analyze the crustal rifting history of the Sinian-Cambrian rift basin, the development pattern of regional syn-sedimentary faults and secondary grabens, and reconstruct the "chessboard" structural prototype of the basin by combining stratigraphic thickness, lithology and structural distribution. (2) Using field geological surveys, drilling, geophysics and remote sensing methods, identify and model the syn-sedimentary fault network in the NE-East and NW-W direction, and determine the main channels for the rise and jetting of deep ore-forming fluids; (3) The mineralization process can be summarized into two stages: the hydrothermal venting stage and the underwater gravity flow deposition stage. a. During the hydrothermal geyser stage, deep ore-forming fluids rise along syn-sedimentary faults, some of which form minerals within the channels, while the vast majority form barite particles through devitrification after emerging from the seabed and accumulate at the edges of secondary grabens. b. During the underwater gravity flow deposition stage, after barite particles accumulate at the edge of the secondary graben, the deposits are triggered by external forces such as earthquakes and storms at the same time. Under the action of gravity flow, they slide on the slope of the secondary graben, resulting in successive landslides (massive structures, deformed bedding), debris flows (patchy structures), and turbidity currents (laminated structures) depositional processes, ultimately forming a complex submarine fan group; (4) Construct geochemical mineral exploration prediction models.

[0007] In one scheme, when identifying the syn-sedimentary fault network, (2) includes conducting a detailed investigation of the development direction, fracture scale, and distribution density of northeast-east and northwest-trending faults, and delineating the deep fluid jet channels and the location of the secondary graben edges.

[0008] In one scheme, during the hydrothermal jet stage described in step (3)a, the ore-forming fluid rises along the structurally weak zone under the influence of strong crustal rifting and syn-sedimentary fractures. Some of the fluid precipitates barite in the channel under the conditions of temperature, salinity and pressure decay. The vast majority of the fluid flows through the fault and onto the seabed, where it forms barite particles through a devitrification-like process and accumulates at the edge of the secondary graben.

[0009] In one scheme, during the underwater gravity flow deposition stage described in step (3)b, the barite deposits undergo landslides and slippage on the slope of the secondary graben under the stimulation of external forces such as earthquakes and storms, which then evolve into clastic flows and eventually form distal turbidity currents. The sedimentary structures from the basin boundary to the deep depression are successively sliding deformation structures, clastic structures and lamellar structures, and are distributed in ring zones.

[0010] In one scheme, the distribution direction of the composite submarine fan group in step (3) is consistent with the distribution direction of the syn-sedimentary fault, the distribution direction of the individual fan body is consistent with the slope direction, the fault plane flows towards the deep depression area, and the corresponding sedimentary facies zone configuration and sedimentary structure change are distributed in a regular ring pattern.

[0011] In one scheme, the mineralization model includes a four-layer structure: ore-guiding structure, ore-distributing structure, ore-hosting space, and sedimentary system, which correspond to the NW-trending main fault, the NE-trending syn-sedimentary normal fault, the secondary graben margin, and the gravity flow fan, respectively, highlighting the coupling relationship between the tectonic-fluid-sedimentary system.

[0012] In one scheme, during the construction of the geochemical mineral exploration prediction model, the trace element content of the ore-bearing rock series is analyzed, and the elements V, Mo, U, Cu, Zn, Ni, and Pb in the top carbonaceous shale and ore layer are selected as mineral exploration indicators. In carbonaceous shale, w(V) is 3500–7300 ppm, w(Mo) is 100–150 ppm, w(U) is 50–90 ppm, w(Cu) is 60–320 ppm, w(Ni) is 140–530 ppm, w(Pb) is 140–215 ppm, and w(Zn) is 930–3190 ppm. The higher the enrichment of the above elements, the closer it is to the mineralization center. Combining the Co / Ni ratio of less than 1 as a characteristic of hydrothermal sedimentation, and using the geochemical characteristics of barite ore layers and enrichment layers with Co / Ni ratios between 0.008 and 0.457, mineral exploration predictions were made. Simultaneously, based on the barite δ... 34 The S isotope value distinguishes the ore-forming center from the peripheral area, while the δ... 34 When the S value is 36.86–47.06‰, it is close to the ore-forming center, δ 34 When the S value is between 38.31 and 43.67‰, it is located on the periphery.

[0013] Beneficial effects of this invention: The present invention has the following beneficial effects: By combining geological structure, sedimentary environment, and geochemical parameters, a metallogenic model for barite deposits was systematically constructed, accurately reflecting the metallogenic mechanism and controlling factors. This method not only improves the scientific rigor and accuracy of barite deposit prospecting prediction but also significantly enhances prospecting efficiency and reduces exploration risks. Utilizing multi-dimensional information such as geochemical prospecting indicators and isotopic characteristics, precise prediction of the spatial distribution of ore bodies can be achieved, providing strong technical support for the exploration, deployment, and development of regional barite resources, and demonstrating promising prospects for widespread application. Attached Figure Description

[0014] Figure 1 A schematic diagram of the hydrothermal jet-deposition process in a barite deposit; Figure 2 Spatial distribution map of barite deposits in eastern Guizhou (a) and prototype of the Sinian-Cambrian residual basin in Tianzhu, Guizhou (b); Figure 3 A simplified diagram of the hydrothermal exhalation-sedimentary mineralization model in barite deposits; Figure 4 This is a characteristic of trace element enrichment in the top layer of a barite ore deposit. Detailed Implementation

[0015] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Typical embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0016] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. To facilitate understanding, the invention will now be described more fully with reference to the accompanying drawings. Typical embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the invention more thorough and complete. A method for constructing a new type of barite deposit mineralization model based on syn-sedimentary faults is as follows: 1. Exhalative sedimentary mineralization (1) Jet mineralization process The barite deposit is located in the lower part of the Jiaoliuchapo Formation, which is part of the Sinian-Cambrian system. The ore-bearing rocks consist of black siliceous rocks, carbonaceous shale interbedded with phosphorite and barite layers. Strontium isotope dating of barite samples from the study area suggests that the deposit was formed with the help of submarine volcanic or hydrothermal activity, providing low-strontium mineral deposits. 87 Sr / 86 The addition of strontium to the Sr ratio suggests that the strontium in barite may originate from mantle-derived strontium. A series of ore-forming materials, including Sr and Ba, from deep layers, under the influence of submarine volcanic activity and gas-liquid activity, formed barium-bearing fluids. These fluids rose along deep faults to favorable locations and gradually accumulated, forming large-scale barium-rich fluid reservoirs. Further rifting of the Sinian-Cambrian rift basin caused the development of syn-sedimentary faults in a downward direction, connecting the barium-rich fluid reservoirs. This resulted in the rapid ascent of the barium-rich fluids along the NE-trending syn-sedimentary faults. During their migration to the shallow seabed, changes in temperature and pressure conditions led to the gradual formation of barite particles, which finally accumulated over a large area along the NE-trending syn-sedimentary normal faults controlling the edges of secondary grabens.

[0017] (2) Sedimentary mineralization process The barite orebody contains two sets of syn-sedimentary faults trending approximately east-west and northwest, which continuously develop to form a series of grabens. Ore-bearing hydrothermal fluids surged along these syn-sedimentary faults to the surface, causing abrupt changes in the physicochemical environment. Barite rapidly crystallized and deposited near the faults. As the flow continued, fine barite crystals accumulated. When the barite accumulation reached a certain height, it was triggered by factors such as fractures, earthquakes, and storms, leading to secondary slippage and deposition of the initially deposited barite orebody, forming underwater gravity fans. This process repeated continuously, with the underwater gravity fans constantly overlapping, eventually forming the primary barite orebody. Figure 1 ).

[0018] 2. Factors controlling ore production 1) The controlling effect of syn-sedimentary structures on barite The control of syn-sedimentary structures in basins over sedimentary mineral deposits is primarily indirect, influencing the formation and accumulation of ore-forming materials by controlling the sedimentary environment. However, the control of barite by syn-sedimentary structures in the Tianzhu Sinian-Cambrian basin is achieved by controlling the distribution of ore-forming material thickness through the control of exhalation channels and depositional spaces. The intensity and amplitude of syn-sedimentary normal fault activity reflect the rate of basement subsidence in rift basins during the rifting period. Secondary grabens provide larger depositional spaces than secondary horsts, allowing them to accommodate more sedimentary ore-forming materials. For example, in the area where the northeast-east trending secondary graben along the river (the section sandwiched between SF2 and SF4) and the north-northwest trending step-like graben (the section sandwiched between SF8 and SF9) intersect, the true thickness of the Liuchapo Formation is 2.19–9.18 m, with an average of 5.48 m, and the true thickness of the barite layer is 1.91–9.18 m, with an average of 4.01 m. However, on the outer side of the graben, the true thickness of the Liuchapo Formation is only 0.80–4.59 m, with an average of 2.23 m, and the true thickness of the barite layer is 0.80–1.91 m, with an average of 1.30 m, a difference of several times. For example, in the area where the northeast-eastward-trending Shanggongtang secondary graben (the section sandwiched between SF5 and SF6) and the north-northwest-trending step-like graben (the section sandwiched between SF9 and SF10) intersect, the true thickness of the Liuchapo Formation is 6.0–16.4 m, with an average of 11.16 m, and the true thickness of the barite layer is 4.65–14.64 m, with an average of 9.62 m. However, on the outer side of the graben, the true thickness of the Liuchapo Formation is only 1.89–5.82 m, with an average of 3.86 m, and the true thickness of the barite layer is 0.82–1.44 m, with an average of 1.13 m. The true thickness differs by more than double.

[0019] 2) The controlling effect of the sedimentation system on barite The underwater gravity flow fan sedimentary system for barite was identified. The control of the underwater gravity flow fan body for barite is caused by the sliding of barite particles ejected from syn-sedimentary faults along the slope of the secondary graben, resulting in slippage → collapse → debris flow → turbidity flow deposition. The fan head exhibits collapse structures with thick and high-grade ore bodies. The fan middle is mostly composed of debris flow structures with moderate grades and thickness. The fan tail exhibits turbidity flow structures with thin and low-grade ore bodies. In other words, the distribution of the fan body strictly controls the distribution of the ore body.

[0020] 3. Metallogenic Model 1) Metallogenic regularity (1) The Tongren Ancient Rift Valley and the Nanhua Rift Valley Basin jointly control the formation and distribution of barite deposits. From the Late Nanhua Period to the Sinian Period, the Nanhua Rift Basin continued to rift and descend, entering a sedimentary stage. This process controlled and formed a super-large-scale hydrothermal sedimentary mineralization process at the Sinian-Cambrian boundary, resulting in the world's largest super-large barite deposit in Tianzhu, Guizhou. ① The Tianzhu-Huitong-Hengshan horst (Level II) during the Sinhua Period began to subside and receive sediments in the Late Sinhua Period. For example, the thickness of the Liangjiehe Formation + Tiesiao Formation in the Middle Sinhua Period was 0–5.31 m, and the thickness of the Datangpo Formation was only 0–7.34 m. However, the thickness of the Nantuo Formation in the Late Sinhua Period increased significantly, reaching 399–536 m. Due to the evolution of the Sinhua Rift Basin, especially the development of multiple near-east-west trending syn-sedimentary faults, secondary grabens were formed. For example, the Bingxi secondary graben in Yuping and the Dahebian-Gongxi secondary graben in Tianzhu. Barite deposits, as well as siderite and vanadium deposits in Yuping, Tianzhu, and Xinhuang areas of Hunan Province, are respectively found in these secondary grabens. Figure 2 The stratigraphic thickness increases anomalously from the Nantuo Formation of the Nanhua System to the Doushantuo Formation and Liuchapo Formation. In the Tianzhu Dahebian-Gongxi secondary graben, the graben is characterized by a thinner thickness on the northwest side and a thicker thickness on the southeast side.

[0021] ② In the Tianzhu River-Gongxi secondary graben, the thickness of the Doushantuo Formation ranges from 2.88 to 217 m. Specifically, the thickness of the overlying Liuchapo Formation ranges from 2.88 to 30 m in areas with barite deposits, and from 50 to 217 m in areas without barite deposits. The thickness of the Liuchapo Formation ranges from 0.7 to 199 m. Specifically, the thickness of the Liuchapo Formation in areas with barite deposits ranges from 0.7 to 60 m (with barite deposit thicknesses ranging from 0.5 to 14.64 m), and from 60 to 199 m in areas without barite deposits. This further indicates that barite deposits are not distributed in the center of the secondary graben basin, but are mainly controlled by syn-sedimentary faults at the edge of the basin. Fluids containing barite and other ore-forming materials are deposited along these syn-sedimentary faults.

[0022] (2) Barite deposits are products of large-scale jet flow and sedimentation of deep-seated barite-rich fluids. Previous theories regarding the genesis of barite deposits include biogenic, chemical, hydrothermal ventral deposition, and cold seep mineralization. Barite deposits are of the hydrothermal ventral-underwater gravity fan sedimentary type, with a very short mineralization time. Deep barium-rich fluids ascend along syn-sedimentary faults. As temperature, salinity, and pressure decrease, the fluids transform into barite particles. After a short period of large-scale ventral deposition at the edges of a series of graben basins, the particles migrate to the center of the graben basin, forming sedimentary structures related to underwater gravity flows, such as slump structures, clastic flow structures, and turbidity current structures.

[0023] (3) Barite ore bodies are distributed along the edges of the Sinian-Cambrian secondary graben. The Sinian-Cambrian hydrothermal-underwater gravity fan sedimentary barite deposits, formed in the Liuchapo period of the Sinian-Cambrian, within the Dahebian-Gongxi remnant basin in Guizhou and Hunan provinces, exhibit a clear spatial distribution of barite, closely related to the rift basin prototype and structure. Specifically, barite is distributed along the edges of secondary grabens, where horst barite deposits are thin or absent, such as the Guilushan barite deposit. Thick, rich ore bodies are distributed along the edges of a rectangular region where a series of secondary grabens intersect with NNE-trending step-like grabens in the Dahebian study area. (4) The barite fan-shaped ore bodies are distributed along the northeast-east direction, while individual ore bodies extend along the north-northwest direction. Prototype basin reconstruction analysis indicates that the Sinian-Cambrian barite-bearing fluid-fluid-underwater gravity flow sedimentary barite deposits were strictly controlled by a series of syn-sedimentary faults and underwater gravity flows. Within the Sinian-Cambrian remnant basin, a "chessboard-like" network of syn-sedimentary normal faults, formed by the intersection of a series of NE-East secondary grabens and NE-W step grabens, controlled the near-north-south orientation of individual barite composite fans. Fan groups composed of multiple barite composite fans generally extended along a 75°–80° NE direction. This is approximately 40° away from the surface Yanshanian NE-trending structure. The barite mining area exhibits a unique "three-layer overpass" structural feature: a NE-W guiding ore-guiding structure in the basement, an NE-East ore-distributing structure in the upper layer, ore-hosting structures at the edges of the secondary grabens, and a NE-W post-genetic ore-breaking structure in the surface layer.

[0024] 2) Metallogenic Model The formation of ore bodies originates from specific geological conditions and geological evolution processes. Although barite deposits originate from deep fluids, they are also influenced by sedimentary environments. Therefore, only by thoroughly understanding the ore-forming geological conditions and geological evolution processes can we grasp the ore-forming laws and establish ore-forming models.

[0025] Metallogenic geological background studies reveal the superposition of multiple phases of rifting in the Tianzhu Dahebian mining area, resulting in a checkerboard graben structure. The convergence of these multiple rift valleys creates a well-developed hydrothermal conduit system. The outflow of large amounts of low-temperature hydrothermal fluids formed primary barite seafloor deposits. Within this complex, checkerboard-like, graben-like topography, the seafloor barite ore bodies diffused outwards via gravity flows, forming multiple barite seafloor fans and creating a sedimentary system conducive to prediction.

[0026] Through comprehensive research and the construction of sedimentary cross sections, identification of syn-sedimentary faults, restoration of basin prototypes, and analysis of sedimentary systems, it was concluded that the intersection of NNE-NE and NE-SE syn-sedimentary faults formed during the Liuchapo Formation period of the Sinian-Cambrian rift basin in Dahebian, Guizhou-Gongxi, Hunan, was likely the main transport channel for deep ore-forming fluids, i.e., a ore-guiding structure. The NE-SE syn-sedimentary faults acted as ore-binding structures for barite mineralization, controlling the overall near-east-west distribution of barite vents. The secondary grabens formed by the activity of the syn-sedimentary faults provided relatively stable ore-hosting space for barite accumulation. Analysis of the barite layer sedimentary system revealed that the underwater gravity flow sedimentary system controlled the morphological distribution of barite mineralization during the Liuchapo period, and the distribution range of the underwater gravity flow fan body corresponds to the distribution range of the barite mineralization. The loose deposits of barite particles ejected from the syn-sedimentary fault network vents slide and collapse along the slope of the secondary graben under the action of external forces. A series of underwater gravity flow deposits, such as slip-slide, debris flow, and turbidity flow, are formed in different parts of the slope. The slip-slide subfacies appears at the head of the fan, with a thick ore body and rich grade. The middle of the fan is mostly composed of debris flow subfacies with slightly lower grade and thickness. The turbidity flow subfacies appears at the tail of the fan, with a thin ore body and poor grade.

[0027] The formation of barite can be broadly categorized into two stages: the hydrothermal vent stage and the underwater gravity flow deposition stage. (1) Hydrothermal geyser stage. Due to intense crustal rifting and the development of syn-sedimentary faults, deep ore-forming fluids rise along the weak structural zones. Some barite-bearing fluids form minerals in the channels when the temperature, salinity, and pressure decrease. Most of the ore-forming fluids flow out of the seabed along syn-sedimentary faults and form barite particles through devitrification-like processes, which then accumulate at the edges of secondary grabens.

[0028] (2) Underwater gravity flow deposition stage. While barite particles accumulate at the edge of the secondary graben, the deposits are triggered by external forces such as earthquakes and storms during the same period. Under the action of gravity flow, they slide along the slope zone of the secondary graben formed by syn-sedimentary faults, resulting in slump and sliding (massive structure, deformed bedding). When the slump and sliding further intensifies, clastic flows (patchy structure) are formed. The clastic flows are then carried by water flow (sliding, fracturing, liquefaction) to the far end, forming turbidity currents (laminated structure). The distribution direction of the fan group is generally the same as that of the syn-sedimentary faults, and the distribution direction of a single fan is generally the same as that of the slope direction, flowing from the fault plane to the deep depression area. Correspondingly, the configuration of sedimentary facies zones corresponds to this, and the changes in sedimentary structures are also regularly distributed in rings. From the boundary of the secondary graben basin outward, the structures are successively sliding deformation structures, clastic structures, and laminated structures.

[0029] In summary, barite deposits are jointly controlled by syn-sedimentary faults (deep fluid jet channels) and underwater gravity flow deposition. Under the combined influence of these two factors, multiple barite composite submarine fan groups with a near-east-west orientation have formed in the Tianzhu-Xinhuang area of ​​Guizhou. Figure 3 ).

[0030] 4. Construct geochemical mineral exploration prediction models (1) Trace elements Based on the trace element content characteristics of the ore-bearing rock series, it can also serve as an indicator for barite prospecting. The carbonaceous shale at the top of the barite ore layer is enriched with elements such as V, Mo, U, Cu, and Zn. The higher the degree of enrichment, the closer it is to the mineralization center. A 1-meter-thick layer of greenish carbonaceous shale is clearly visible in the Dadaibai and Dagongtang sections. w (V) ranges from 3500 to 7300 ppm. w (Mo) is 100-150 ppm. w (U) is 50–90 ppm, w (Cu) ranges from 60 to 320 ppm. w (Ni) is 140–530 ppm, w (Pb) is 140–215 ppm, w (Zn) is 930-3190 ppm. The presence of hyperenriched layers of these elements often indicates the presence of a barite ore layer underneath. The higher the enrichment level, the closer to the ore layer. Figure 4 ).

[0031] Generally, a Co / Ni ratio less than 1 is characteristic of hydrothermal sedimentation. In the Tianzhu black rock series, the Co / Ni ratio of the barite ore layer is 0.457, the Co / Ni ratio of the Ni and Mo enriched layer is 0.008, and the Co / Ni ratio of the V enriched layer is 0.075, all much less than 1, indicating obvious hydrothermal sedimentary characteristics. Therefore, the Co / Ni ratio in the Cambrian black rock series can also be used as a reference indicator for barite prospecting; that is, a relatively high Co / Ni ratio, close to 0.5, will indicate the presence of barite deposits.

[0032] (2) Sulfur isotopes The Tianzhu barite deposit exhibits a massive-patterned-laminated sedimentary sequence from bottom to top. Sulfate sulfur isotope studies show that the laminar barite has a δ¹⁴ tbsp structure. 34 High S value, ranging from 36.86 to 47.06‰, with an average of 42.17‰, mottled barite δ 34 The S value ranges from 41.50 to 42.27‰, with an average of 41.88‰. The banded barite exhibits δ... 34 The S value ranges from 38.31 to 43.67‰, with an average of 41.77‰. Barite in disc and columnar shapes exhibits δ¹⁸O₂. 34 S values ​​are generally high, ranging from 46.81 to 49.81‰, with an average of 47.90‰ and a maximum of +49.81‰. The top and bottom plates of the barite deposit along the riverbank have δ... 34 The S value is low (+10~+30‰), and the barite mineral layer has a δ 34 The S value is relatively high (+35 to +50‰).

[0033] There is a clear correlation between the structure and sulfur isotopes of barite in different regions. Fine-grained layered barite, with its high grade, has a heavier sulfur isotope content; mottled barite, with its relatively high grade, also has a heavier sulfur isotope content; while banded and siliceous massive barite, with its low grade, has a lower sulfur isotope content. Therefore, in the mineralization center, barite sulfur isotopes are relatively high, ranging from 36.86 to 47.06‰, with an average of 42.17‰; while in the periphery of the mineralization center, barite sulfur isotopes are lower, generally ranging from 38.31 to 43.67‰, with an average of 41.77‰. Higher sulfur isotope content in barite corresponds to a closer proximity to the mineralization center.

[0034] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0035] It should be understood that the above detailed description of the technical solutions of the present invention with reference to preferred embodiments is illustrative and not restrictive. Those skilled in the art can modify the technical solutions described in the embodiments or make equivalent substitutions for some of the technical features based on reading this specification; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a new type of barite deposit metallogenic model based on synsedimentary faults, characterized in that: The method comprises the following steps: (1) analyzing the crustal rifting activity history of the Sinian-Cambrian fault basin, the development pattern of regional synsedimentary faults and secondary grabens, and restoring the "checkerboard" structure prototype of the basin in combination with the stratum thickness, lithology and tectonic distribution; (2) identifying and modeling the synsedimentary fault network in the north-east and north-west directions by means of field geological investigation, drilling engineering, geophysical and remote sensing geological big data, and determining the main channel of deep ore-forming fluid rising and jetting; (3) summarizing the ore-forming process into two stages, namely, the hydrothermal jetting stage and the underwater gravity flow deposition stage: a. In the hydrothermal jetting stage, the deep ore-forming fluid rises along the synsedimentary fault, part of which is mineralized in the channel, and most of which is formed into barite particles by the devitrification-like action after being jetted out of the seabed and accumulated at the edge of the secondary graben; b. In the underwater gravity flow deposition stage, after the barite particles are accumulated at the edge of the secondary graben, the accumulation body is triggered by the external force of the earthquake and storm, and slides on the slope of the secondary graben under the action of gravity flow, and in turn produces the sliding and sliding (massive structure, deformed bedding), debris flow (mottled structure) and turbidity current (laminated structure) deposition, and finally forms a composite submarine fan body group; (4) constructing a geochemical ore-prospecting prediction model.

2. The method according to claim 1, characterized in that: In the step (2), the development direction, fault scale and distribution density of the faults in the north-east and north-west directions are investigated in detail, and the deep fluid jetting channel and the edge of the secondary graben are circled.

3. The method according to claim 1, characterized in that: In the step (3) a, in the hydrothermal jetting stage, the ore-forming fluid rises along the tectonic weak zone under the action of strong crustal rifting and synsedimentary faulting, part of the fluid is precipitated in the channel under the conditions of temperature, salinity and pressure attenuation, and most of the fluid is jetted out of the seabed through the fault and formed into barite particles by the devitrification-like action and accumulated at the edge of the secondary graben.

4. The method according to claim 1, characterized in that: In the step (3) b, in the underwater gravity flow deposition stage, the barite accumulation body is excited by the external force of the earthquake and storm, and produces the sliding and sliding on the slope of the secondary graben, and then evolves into the debris flow, and finally forms the distal turbidity current, and the sedimentary structure is in turn sliding deformation structure, debris structure and laminated structure from the basin boundary to the deep depression area, and presents a regular zonal distribution.

5. The method according to claim 1, characterized in that: In the step (3), the composite submarine fan body group is distributed in the same direction as the synsedimentary fault, the single fan body is distributed in the same direction as the slope, the fault plane flows to the deep depression area, and the corresponding sedimentary facies belt configuration and the change of sedimentary structure present a regular zonal distribution.

6. The method according to claim 1, characterized in that: The ore-forming model comprises four layers of structure of ore guide structure, ore matching structure, ore hosting space and sedimentary system, which respectively correspond to the north-west main fault, the north-east synsedimentary normal fault, the secondary graben edge and the gravity flow fan, and highlights the coupling relationship of the tectonic-fluid-sedimentary system.

7. The method according to claim 1, characterized in that: In the process of constructing the geochemical ore-prospecting prediction model, the content of trace elements in the ore-bearing rock series is analyzed, and V, Mo, U, Cu, Zn, Ni and Pb elements in the roof carbonaceous shale and ore layer are selected as the ore-prospecting marks. The w(V) in the carbonaceous shale is 3500-7300 ppm, w(Mo) is 100-150 ppm, w(U) is 50-90 ppm, w(Cu) is 60-320 ppm, w(Ni) is 140-530 ppm, w(Pb) is 140-215 ppm, and w(Zn) is 930-3190 ppm, and the higher the enrichment of the above elements, the closer to the ore-forming center. Combined with the feature of Co / Ni value less than 1, the authors used the geochemical feature of Co / Ni value between 0.008 and 0.457 in barite ore bed and enrichment layer to predict the ore deposit, and used the value of barite δ 34 S isotope to distinguish the ore-forming center and peripheral area. When the value of δ 34 S is between 36.86 and 47.06‰, it is close to the ore-forming center, and when the value of δ S is between 38.31 and 43.67‰, it is in the peripheral area.

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