A model for prospecting a sedimentary barite deposit

Abstract

The application discloses a kind of sedimentary barite deposit prospecting model, and its establishing method is first to the spatial distribution law prediction of sedimentary barite deposit;According to the same fault of fracture discrimination;According to the sedimentary sequence, ore structure, ore grade, determine the deposit sedimentation center;Second, the distribution of ore bed is determined using the enrichment degree of trace elements;Obtain the sulfur isotope data in the prediction area and as data sample;Again, the data sample obtained is processed to obtain eigenvalue;And the eigenvalue obtained is matched with the model of barite deposit to determine the center phase and edge phase of sedimentary barite deposit;Again, the position of barite layer is determined by matching with resistivity model using geophysical method.The application solves the problems of high cost of determining sedimentary center and ore body distribution, etc.

Description

Technical Field

[0001] This invention relates to the field of geological prospecting, and in particular to a prospecting model for sedimentary barite deposits, belonging to the field of mineral deposit exploration. Background Technology

[0002] Barite is one of the advantageous mineral resources in Guizhou Province. Among them, sedimentary barite deposits are the most typical, mainly distributed in Tianzhu, Yuping, Zhenning, Majiang and other areas. Tianzhu has the world's largest sedimentary barite deposit. The Tianzhu Dahebian barite deposit has proven reserves of 166 million tons, making it the world's largest sedimentary barite deposit and the most representative deposit in the barite metallogenic belt on the southern margin of the Yangtze Block.

[0003] The Tianzhu barite deposit was discovered as early as 1937. Through more than 80 years of exploration and research, studies have been conducted on the sedimentary sequence of the ore-bearing rock series, mineralogical analysis, fluid inclusion analysis, elemental geochemistry, organic geochemistry, isotopic geochemistry, analysis of sedimentary basins and metallogenic models. Although a large number of research results have been achieved in recent years, the metallogenic regularity of the region, the hydrothermal (cold seep) flow center, the regional ore body distribution and paleotectonic relationship have not been studied in depth, which affects the construction of metallogenic models and prospecting models. Summary of the Invention

[0004] To address the challenges of finding barite deposits and the high costs associated with determining sedimentary centers and ore body distribution, this invention provides a sedimentary barite deposit exploration model. This model selects areas using paleogeographic maps to identify uplift zones and fault zones, determines the sequence structure and mineralization center through sedimentary sequence analysis, identifies the ore structure, ore grade, and mineralization center through stratigraphic core logging, determines the ore layer distribution and mineralization center through geochemical analysis, and finally determines the location of the ore layer through geophysical analysis.

[0005] The technical solution for achieving the objective of this invention is as follows:

[0006] A prospecting model for sedimentary barite deposits, the method for establishing which includes at least the following steps:

[0007] (1) Selecting areas for paleogeographic maps to determine the distribution of uplifted areas and fault zones.

[0008] (1.1) Identify uplifted areas and fault zones based on the lithology, sedimentary facies, and geological structures of each stratum in the geological data;

[0009] (1.2) Based on the Early Cambrian paleogeographic map of South China, the spatial distribution pattern of sedimentary barite deposits is predicted;

[0010] (2) Sequence analysis of sedimentary strata to determine the sequence structure and mineralization center.

[0011] (2.1) Determine the sedimentary sequence of the ore-bearing rock series based on typical marker beds;

[0012] (2.2) Determine the mineralization center based on sedimentary cycles and sedimentary facies;

[0013] (3) Stratigraphic core logging to determine ore structure, ore grade and metallogenic center.

[0014] (3.1) Based on the drilling results of the stratigraphic core, determine the distribution of ore structure and ore grade.

[0015] (3.2) Determine the mineralization center of the barite deposit based on the ore structure, ore grade, and mineral composition;

[0016] (4) Geochemical analysis to determine the distribution of ore layers and metallogenic centers.

[0017] (4.1) Determine the distribution of ore layers based on the enrichment degree of trace elements in carbonaceous shale;

[0018] (4.2) Obtain sulfur isotope data of sedimentary barite in the prediction area and use these data as data samples;

[0019] (4.3) Process the data samples obtained in step (4.2) to obtain feature values;

[0020] (4.4) Match the eigenvalues ​​obtained in step (4.3) with the model of the barite deposit to determine the central and peripheral phases of the barite deposit;

[0021] The central phase model of sedimentary barite deposits is as follows: the sulfur isotope is relatively high, ranging from 36.86 to 47.06‰, with an average of 42.17‰;

[0022] The marginal phase model of sedimentary barite deposits is as follows: low sulfur isotope, ranging from 38.31 to 43.67‰, with an average of 41.77‰;

[0023] (5) Geophysical analysis to determine the location of the ore layer

[0024] (5.1) Obtain the resistivity data of sedimentary barite in the prediction area and use these data as data samples;

[0025] (5.2) Process the data samples obtained in step (5.1) to obtain feature values;

[0026] (5.3) Match the eigenvalues ​​obtained in step (5.2) with the model of the barite deposit to determine the distribution of the barite ore layer;

[0027] The top plate model of the sedimentary barite deposit is: a low-resistivity carbonaceous shale layer with a resistivity of 1116 Ω·m;

[0028] The ore layer model of the sedimentary barite deposit is: a high-resistivity barite layer with a resistivity of 3805 Ω·m;

[0029] The base model of the sedimentary barite deposit is: a low-resistivity argillaceous dolomite layer with a resistivity of 2405 Ω·m.

[0030] A further improvement to the above technical solution is as follows: Step (1.2) involves predicting the spatial distribution pattern of sedimentary barite deposits based on the Early Cambrian paleogeographic map of South China, specifically through the following steps:

[0031] (1.2.1) Divide the mapping units into special units closely related to barite mineralization;

[0032] (1.2.2) Draw the spatial distribution range of the special mapping units on the remote sensing image map in the geological data;

[0033] (1.2.3) Based on the syn-sedimentary faults, draw the spatial distribution and strike of the syn-sedimentary faults during the mineralization period;

[0034] (1.2.4) The Qingbaikou System of the Neoproterozoic Xiajiang Group was identified as a deep-sea basin; the Nanhua System of the Neoproterozoic was identified as a coastal basin; the Doushantuo Formation of the Sinian System was identified as a shallow-water platform facies and a shallow-sea shelf facies; the Liuchapo Formation (Laobao Formation) of the Upper Sinian-Lower Cambrian was identified as a semi-deep-sea basin; and the Niutitang Formation of the Lower Cambrian was identified as a reverting slope facies.

[0035] (1.2.5) A paleogeographic map is formed by overlaying syn-sedimentary faults and sedimentary facies distribution maps during the mineralization period;

[0036] (1.2.6) Predict the spatial distribution pattern of sedimentary barite deposits based on paleogeographic maps.

[0037] Furthermore, step (2.2) is obtained based on sedimentary cycles and sedimentary facies through the following steps:

[0038] (2.2.1) Select sections with complete strata and good outcrops to carry out geological profile measurement work;

[0039] (2.2.2) At a scale of 1:2000, sedimentary facies profiles of each section closely related to the barite mineralization period were constructed, including sedimentary facies profiles of the underlying strata, the strata of the mineralization period, and the overlying strata of the mineralization period.

[0040] (2.2.3) Based on the measured sedimentary profiles, analyze them using the stratigraphic thickness contour method and compile sedimentary profile maps for different regions.

[0041] Furthermore, the ore structure in step (3.2) includes finely layered, mottled, banded, and dense siliceous materials.

[0042] The trace elements in step (4.1) include V, Mo, U, Cu, Ni, Pb, and Zn.

[0043] Furthermore, the model for the barite deposit in step (5.3) is an audio-frequency magnetotelluric prediction model.

[0044] As can be seen from the above technical solutions: (1) This model determines the existence of barite ore layers by identifying the existence of syngenetic fractures, and predicts the spatial distribution pattern of the ore deposit;

[0045] (2) This model further determines the barite mineralization center by analyzing the spatial distribution direction and regularity of the ore-bearing rock series;

[0046] (3) By matching this model with the sulfur isotope model, the central and peripheral phases of barite deposits are further determined;

[0047] (4) This model determines the location of the barite layer by matching it with the resistivity model. Attached Figure Description

[0048] Figure 1 A paleogeographic map of South China during the Early Cambrian period;

[0049] Figure 2 Map showing the mineralization controlled by ancient uplifts and faults;

[0050] Figure 3 Diagrams of barite ores with different structures;

[0051] Figure 4 This diagram shows the contact relationship between the trace element enrichment layer and the barite mineral layer. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. However, the scope of the present invention is not limited to the following embodiments.

[0053] A prospecting model for sedimentary barite deposits, the method of which includes the following steps:

[0054] (1) Paleogeographic map selection area, determining the distribution of uplifted areas and fault zones, Early Cambrian paleogeographic map of South China ( Figure 1 The data shows that ancient islands exist in the Qinling Mountains to the north of the Yangtze Block, the Jiangnan Orogenic Belt to the southeast, Tianzhu in Guizhou, and Duchang in Jiangxi. These islands may be uplifted areas of the Jiangnan Orogenic Belt and the Qinling Orogenic Belt. The ancient islands may be in the central uplifted area, with large faults developed on both sides.

[0055] (1.1) Based on the lithology, sedimentary facies, and geological structure of each stratum in the geological data, the uplifted area and the fault zone are identified. Syngenetic faults connect deep hydrothermal ore-forming fluids, which are ejected from the seabed through the faults to form barite deposits. Figure 2 );

[0056] (1.2) Based on the Early Cambrian paleogeographic map of South China, the spatial distribution pattern of sedimentary barite deposits is predicted, including the following sub-steps:

[0057] (1.2.1) Divide the special mapping units closely related to barite mineralization; the slightly metamorphosed clastic rocks are divided into the Neoproterozoic Qingbaikou System Xiajiang Group; the glacial till is divided into the Neoproterozoic Nanhua System; the dolomite is divided into the Sinian System Doushantuo Formation; the siliceous rocks and barite are divided into the Upper Sinian-Lower Cambrian Liuchapo Formation (Laobao Formation); the carbonaceous shale is divided into the Lower Cambrian Niutitang Formation;

[0058] (1.2.2) Draw the spatial distribution range of the special mapping units on the remote sensing image map in the geological data;

[0059] (1.2.3) Based on the syn-sedimentary faults, draw the spatial distribution and strike of the syn-sedimentary faults during the mineralization period;

[0060] (1.2.4) The Qingbaikou Group of the Neoproterozoic was identified as a deep-sea basin; the Nanhua Group of the Neoproterozoic was identified as a coastal basin; the Doushantuo Formation of the Sinian System was identified as a shallow-water platform facies and a shallow-sea shelf facies; the Liuchapo Formation (Laobao Formation) of the Upper Sinian-Lower Cambrian was identified as a semi-deep-sea basin; and the Niutitang Formation of the Lower Cambrian was identified as a reductive slope facies.

[0061] (1.2.5) A paleogeographic map is formed by overlaying syn-sedimentary faults and sedimentary facies distribution maps during the mineralization period;

[0062] (1.2.6) Predict the spatial distribution pattern of sedimentary barite deposits based on paleogeographic maps.

[0063] (2) Sequence analysis of sedimentary strata to determine the sequence structure and mineralization center.

[0064] (2.1) Based on typical marker layers, the sedimentary sequence of the ore-bearing rock system is determined. The barite deposit is located between the upper and lower "nodule layers". The top layer is carbonaceous shale and siliceous rock interbedded with barite nodules, with a thickness of less than 2 meters. The bottom layer is carbonaceous shale interbedded with barite nodules, with a thickness of less than 1 meter. Next is dolomite. The top of the dolomite on the bottom plate is barite mineralized, and a thicker barite ore layer is often deposited on it.

[0065] (2.2) Determine the mineralization center based on sedimentary cycles and sedimentary facies, specifically through the following steps;

[0066] (2.2.1) Select sections with complete strata and good outcrops to carry out geological profile measurement work;

[0067] (2.2.2) At a scale of 1:2000, sedimentary facies profiles of each section closely related to the barite mineralization period were constructed, including sedimentary facies profiles of the underlying strata, the strata of the mineralization period, and the overlying strata of the mineralization period.

[0068] (2.2.3) Based on the measured sedimentary profiles, analyze the sedimentary profile maps of different regions using the stratigraphic thickness contour method.

[0069] The barite mineralization involved two sedimentary cycles. The Dadaibai area served as the sedimentary center, with the thickest barite deposits and two distinct sedimentary cycles. The first sedimentary cycle gradually pinched outwards. The second sedimentary cycle was more widely distributed, reaching a thickness of 4-5 meters in the Dahebian-Dagongtang area. The presence of coarse-grained limestone layers within the carbonaceous shale at the top of the ore layer indicates relatively shallow water. The more developed the coarse-grained limestone, the less favorable it is for barite deposition. In the Zhaijiao mining area, 1-2 layers of limestone interlayers are commonly found within the carbonaceous shale at the top, with the barite ore layer only 1-3 meters thick. The thickness of the Doushantuo Formation dolomite at the bottom of the ore layer also reflects the depth of the sedimentary water during the mineralization period. A thickness of 15-30 meters in the Doushantuo Formation dolomite is most favorable for barite mineralization. A thickness of less than 15 meters (deep-water environment) or greater than 40 meters (shallow-water platform environment) in the Doushantuo Formation dolomite is unfavorable for barite mineralization.

[0070] (3) Stratigraphic core logging to determine ore structure, ore grade and metallogenic center.

[0071] (3.1) Based on the drilling results of the stratigraphic cores, the distribution of ore structure and ore grade is determined. The mineralization center is generally composed of fine-grained layered barite with high barite grade. w (BaSO4) content is over 90%; mottled and banded barite are located near the periphery of the mineralization, and the barite grade is lower. w (BaSO4) content is 70-80%; the outermost layer of the mineralization is generally composed of dense siliceous barite with low barite grade. w (BaSO4) is 50-60% Figure 3 );

[0072] (3.2) Based on the ore structure, ore grade, and mineral composition, the mineralization center of a barite deposit can be determined. The greater the thickness of fine-grained barite ore, the closer it is to the mineralization center. Siliceous barite ore generally appears at the mineralization edge far from the mineralization center, while mottled and banded barite ore is close to the mineralization center. Therefore, the mineralization center can be determined by the ratio of the thickness of dense-grained barite ore to the thickness of mottled and banded barite ore. In addition, calcite is often developed in the barite-rich ore area of ​​the mineralization center, while dolomite is often developed in the barite surrounding the mineralization center.

[0073] (4) Geochemical analysis to determine the distribution of ore layers and metallogenic centers.

[0074] (4.1) Based on the enrichment degree of trace elements in the carbonaceous shale, the distribution of the ore layer was determined. The carbonaceous shale on the top of the barite ore layer is enriched with elements such as V, Mo, U, Cu, and Zn. The higher the enrichment degree, the closer it is to the ore-forming center. A 1-meter-thick layer of greenish carbonaceous shale was clearly seen in the Dadaibai and Dagongtang sections. 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, w (Zn) is 930-3190ppm, and the presence of hyperenriched layers of the above elements often indicates the presence of a barite mineral layer underneath. Figure 4 );

[0075] (4.2) Obtain sulfur isotope data of sedimentary barite in the prediction area and use these data as data samples;

[0076] (4.3) Process the data samples obtained in step (4.2) to obtain feature values;

[0077] (4.4) Match the eigenvalues ​​obtained in step (4.3) with the model of the barite deposit to determine the central and peripheral phases of the barite deposit;

[0078] The central phase model of sedimentary barite deposits is as follows: the sulfur isotope is relatively high, ranging from 36.86 to 47.06‰, with an average of 42.17‰;

[0079] The marginal phase model of sedimentary barite deposits is as follows: low sulfur isotope, ranging from 38.31 to 43.67‰, with an average of 41.77‰;

[0080] (5) Geophysical analysis to determine the location of the ore layer

[0081] (5.1) Obtain the resistivity data of sedimentary barite in the prediction area and use these data as data samples;

[0082] (5.2) Process the data samples obtained in step (5.1) to obtain feature values;

[0083] (5.3) Match the eigenvalues ​​obtained in step (5.2) with the model of the barite deposit to determine the distribution of the barite ore layer;

[0084] The top plate model of the sedimentary barite deposit is: a low-resistivity carbonaceous shale layer with a resistivity of 1116 Ω·m;

[0085] The ore layer model of the sedimentary barite deposit is: a high-resistivity barite layer with a resistivity of 3805 Ω·m;

[0086] The base model of the sedimentary barite deposit is: a low-resistivity argillaceous dolomite layer with a resistivity of 2405 Ω·m.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Any modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions for some of the technical features, are within the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for establishing a prospecting model for sedimentary barite deposits, characterized in that: At least the following steps are included: (1) Selecting areas for paleogeographic maps to determine the distribution of uplifted areas and fault zones. (1.1) Identify uplifted areas and fault zones based on the lithology, sedimentary facies, and geological structures of each stratum in the geological data; (1.2) Based on the Early Cambrian paleogeographic map of South China, the spatial distribution pattern of sedimentary barite deposits is predicted; (2) Sequence analysis of sedimentary strata to determine the sequence structure and mineralization center. (2.1) Determine the sedimentary sequence of the ore-bearing rock series based on typical marker beds; (2.2) Determine the mineralization center based on sedimentary cycles and sedimentary facies; (3) Stratigraphic core logging to determine ore structure, ore grade and metallogenic center. (3.1) Based on the drilling results of the strata core, determine the distribution of ore structure and ore grade; (3.2) Determine the mineralization center of the barite deposit based on the ore structure, ore grade, and mineral composition; (4) Geochemical analysis to determine the distribution of ore layers and metallogenic centers. (4.1) Determine the distribution of ore layers based on the enrichment degree of trace elements in carbonaceous shale; (4.2) Obtain sulfur isotope data of sedimentary barite in the prediction area and use these data as data samples; (4.3) Process the data samples obtained in step (4.2) to obtain feature values; (4.4) Match the eigenvalues ​​obtained in step (4.3) with the sulfur isotope prospecting discrimination model established based on the measured data of known deposits to determine the central phase and edge phase of the barite deposit; The central phase model of sedimentary barite deposits is as follows: the sulfur isotope is relatively high, ranging from 36.86 to 47.06‰, with an average of 42.17‰; The marginal phase model of sedimentary barite deposits is as follows: low sulfur isotope, ranging from 38.31 to 43.67‰, with an average of 41.77‰; (5) Geophysical analysis to determine the location of the ore layer (5.1) Obtain the resistivity data of sedimentary barite in the prediction area and use these data as data samples; (5.2) Process the data samples obtained in step (5.1) to obtain feature values; (5.3) Match the feature values ​​obtained in step (5.2) with the three-layer resistivity prospecting discrimination model established based on the known mining area measured data, and determine the distribution of barite ore layer by identifying the three-layer electrical structure features of "low resistance-high resistance-low resistance", wherein the resistivity model is used for audio magnetotelluric prediction. The top plate model of the sedimentary barite deposit is: a low-resistivity carbonaceous shale layer with a resistivity of 1116 Ω·m; The ore layer model of the sedimentary barite deposit is: a high-resistivity barite layer with a resistivity of 3805 Ω·m; The base model of the sedimentary barite deposit is: a low-resistivity argillaceous dolomite layer with a resistivity of 2405 Ω·m.

2. The method for establishing a prospecting model for sedimentary barite deposits according to claim 1, characterized in that: Step (1.2) involves predicting the spatial distribution of sedimentary barite deposits based on the Early Cambrian paleogeographic map of South China, specifically through the following steps: (1.2.1) Divide the mapping units into special units closely related to barite mineralization; (1.2.2) Draw the spatial distribution range of the special mapping units on the remote sensing image map in the geological data; (1.2.3) Based on the syn-sedimentary faults, draw the spatial distribution and strike of the syn-sedimentary faults during the mineralization period; (1.2.4) The Qingbaikou System of the Neoproterozoic Xiajiang Group was identified as a deep-sea basin; the Nanhua System of the Neoproterozoic was identified as a coastal basin; the Doushantuo Formation of the Sinian System was identified as a shallow-water platform facies and a shallow-sea shelf facies; the Liuchapo Formation of the Upper Sinian-Lower Cambrian was identified as a semi-deep-sea basin; and the Niutitang Formation of the Lower Cambrian was identified as a reverting slope facies. (1.2.5) A paleogeographic map is formed by overlaying syn-sedimentary faults and sedimentary facies distribution maps during the mineralization period; (1.2.6) Predict the spatial distribution pattern of sedimentary barite deposits based on paleogeographic maps.

3. The method for establishing a prospecting model for sedimentary barite deposits according to claim 1, characterized in that: Step (2.2) is obtained based on sedimentary cycles and sedimentary facies through the following steps: (2.2.1) Select sections with complete strata and good outcrops to carry out geological profile measurement work; (2.2.2) At a scale of 1:2000, sedimentary facies profiles of each section closely related to the barite mineralization period were constructed, including sedimentary facies profiles of the underlying strata, the strata of the mineralization period, and the overlying strata of the mineralization period. (2.2.3) Based on the measured sedimentary profiles, analyze them using the stratigraphic thickness contour method and compile sedimentary profile maps for different regions.

4. The method for establishing a prospecting model for sedimentary barite deposits according to claim 1, characterized in that, The ore structure in step (3.2) includes one or more of the following: fine-textured, mottled, banded, and dense siliceous structures.

5. The method for establishing a prospecting model for sedimentary barite deposits according to claim 1, characterized in that, The trace elements in step (4.1) include at least V, Mo, U, Cu, Ni, Pb, and Zn.

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