A method for determining the ore-forming mechanism of a volcanic-intrusive type iron deposit based on a hidden explosion breccia pipe

Abstract

The application discloses a kind of based on hidden explosion breccia pipe Volcano-intrusive type iron deposit metallogenic mechanism determination method, belong to mineral geological exploration technical field.The method includes: underground geological feature exploration, preliminary determination of ore-forming characteristics by the corresponding relationship of the zonal distribution characteristics of hidden explosion breccia pipe and surface radial cleavage;Magnetite geochemical test and iron source area tracing, use LA-ICP-MS micro area composition analysis and sulfur isotope test to verify the correlation of hidden explosion breccia pipe mineralization and deep magma;Ore body characteristic identification and verification, the matching of ore body and rock pipe, etc. Characteristics such as magnetite crystal form are used to verify the ore-forming characteristics;Metallogenic mechanism distinguishes and finally determines.The present application first discovers the superposition phenomenon of hidden explosion breccia pipe metallogenic mechanism and traditional mechanism in Volcano-intrusive type iron deposit, and the determination method is accurate and reliable, which can provide a theoretical basis for prospecting and mining in the boundary area of Volcano-intrusive type iron deposit, and effectively improve the efficiency of mineral exploration and mining.

Description

Technical Field

[0001] This invention relates to the field of mineral geological exploration technology, specifically to a method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes. Background Technology

[0002] Volcanic-intrusive iron ore deposits are one of the important types of iron ore resources in my country, with terrestrial volcanic rock type deposits being a typical example. Existing research suggests that their mineralization mechanisms are mainly of two types: immiscible volcanic magma and hydrothermal metasomatic volcanic magma, manifested respectively as iron-rich magma penetrating and filling fractures to form mineralization, and iron-rich high-temperature hydrothermal fluids metasomatically altering the surrounding rocks to form mineralization. However, in actual mining operations, the occurrence characteristics of boundary ore bodies often differ significantly from those of the main ore body, and existing mineralization mechanism theories cannot effectively explain the abrupt changes in the thickness, dip, and strike of these boundary ore bodies. This leads to a high waste rock contamination rate and low recovery rate during ore body extraction, and also makes it difficult to guide prospecting work in boundary areas.

[0003] Currently, the determination of the mineralization mechanism of volcanic-intrusive iron ore deposits mainly focuses on the two traditional mechanisms mentioned above: magma intrusion and hydrothermal alteration. No research has systematically revealed the phenomenon of the superposition of cryptovolcanic breccia mineralization mechanisms with traditional mineralization mechanisms, and there is a lack of a comprehensive determination method that combines underground geological exposure characteristics, geochemical testing, and orebody feature identification. This deficiency leads to the inability to accurately identify the mineralization characteristics of cryptovolcanic breccia, thus restricting the mineral exploration and mining efficiency in the boundary areas of volcanic-intrusive iron ore deposits. Summary of the Invention

[0004] The purpose of this invention is to provide a method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes, thereby solving the problem in existing technologies that cannot identify the mineralization mechanism of cryptovolcanic breccia in volcanic-intrusive iron deposits. This invention aims to achieve accurate determination of the mineralization mechanism of cryptovolcanic breccia, while effectively distinguishing it from magma intrusion and hydrothermal alteration mineralization mechanisms, thus providing a scientific and reliable theoretical basis for mineral exploration and mining in the boundary areas of volcanic-intrusive iron deposits.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes, comprising the following steps: S1. Underground geological feature exploration: Geological logging of underground rock tunnels and exploration pits at the mining boundary of volcanic-intrusive iron ore deposits, and exploration to investigate whether there are cryptovolcanic breccia pipes. The cryptovolcanic breccia pipes are distributed in a ring around the hydrothermal blasting center, and from the inside out are the blasting breccia zone, the fractured rock zone, and the seismic fractured rock zone. At the same time, investigate whether there are radial cleavages on the surface of the deposit, and determine whether the planar position of the radial cleavages on the surface corresponds to the planar position of the underground cryptovolcanic breccia pipe; If the above-mentioned cryptovolcanic breccia pipes with the above-mentioned ring distribution are found underground, and the radial cleavage on the surface corresponds to the location of the underground pipes, it is preliminarily determined that the deposit has the geological characteristics of cryptovolcanic breccia mineralization. S2. Magnetite geochemical testing and iron source tracing: Magnetite samples were collected from cryptovolcanic breccia pipes, and LA-ICP-MS micro-area composition analysis and sulfur isotope composition testing were performed on the samples. The genetic types of magnetite are analyzed using multi-component genetic discrimination diagrams of TiO2-Al2O3-(MgO+MnO), Al+Mn-Ti+V, and Ti-Ni / Cr. Based on the sulfur isotope test results, determine whether the sulfur source is a mixed source of deep crust / upper mantle and Triassic marine gypsum sulfur; If the micro-regional compositional characteristics of magnetite are concentrated in volcanic / magmatic regions, and the sulfur source is a mixture of deep-seated and marine gypsum-sulfur sources, and the Cr content is consistent, indicating that the iron is of the same origin, then it is determined that the iron in magnetite originates from a deep magmatic system, verifying the correlation between cryptovolcanic breccia mineralization and deep magma. S3. Identification and verification of ore body characteristics: Observe the shape, occurrence, occurrence elevation and scale of the ore body in the cryptovolcanic breccia pipe, and determine whether it is highly consistent with the shape, occurrence, occurrence elevation and scale of the cryptovolcanic breccia pipe. Simultaneously identify the crystal form, ore-rock boundary characteristics, and grade distribution characteristics of magnetite in the ore body: If the magnetite has a coarse-grained structure, a clear ore-rock boundary without any signs of gradual change, and a grade that is distributed in a ring-like pattern with a significantly higher grade near the hydrothermal explosion center, then the mineralization characteristics of the cryptovolcanic breccia are verified. S4. Differentiation and final determination of mineralization mechanisms: Establish an index system for identifying ore body characteristics of cryptovolcanic breccia mineralization, magma intrusion, and hydrothermal alteration mineralization mechanisms, and differentiate the three mineralization mechanisms through index comparison. If step S1 preliminarily determines the presence of cryptovolcanic breccia mineralization geological characteristics, step S2 verifies that the iron originates from deep magma and is associated with cryptovolcanic breccia mineralization, and step S3 verifies the ore body characteristics of cryptovolcanic breccia mineralization, then it is finally determined that the volcanic-intrusive iron deposit has a cryptovolcanic breccia mineralization mechanism, and this mechanism, combined with the magma intrusion and hydrothermal alteration mineralization mechanisms, forms a high-quality ore body.

[0006] Preferably, the test indicators for LA-ICP-MS micro-area component analysis in step S2 include the content and ratio of elements TiO2, Al2O3, MgO, MnO, Ti, V, Ni, Cr, Sn, and Ga.

[0007] Preferably, in the ore body characteristic identification index system described in step S4, the characteristics of cryptovolcanic breccia mineralization are: magnetite has a coarse-grained crystalline structure, clear ore-rock boundary with no signs of hydrothermal alteration, ore body morphology / occurrence / occurrence elevation / scale consistent with the breccia pipe, grade distributed in a ring-like pattern with an unusually high grade near the blasting center; the characteristics of magma intrusion mineralization are: magnetite has a fine- to medium-grained structure, veins intruding along fractures, and relatively uniform grade; the characteristics of hydrothermal alteration mineralization are: The boundary between the ore and rock shows signs of gradual change. The magnetite has a medium-grained texture and is accompanied by a large number of hydrothermal alteration minerals. The grade is distributed in a gradual manner.

[0008] Preferably, for deposits where no radial cleavage is found on the surface, if a cryptovolcanic breccia pipe with a clear ring distribution is exposed underground, and the mineralization characteristics of cryptovolcanic breccia are verified by steps S2 and S3, it can still be determined that the deposit has a cryptovolcanic breccia mineralization mechanism.

[0009] Preferably, in step S3, the location of the hydrothermal blasting center is verified by combining the magnetic iron grade data of the exploration boreholes, and the borehole section with the highest magnetic iron grade is the area near the hydrothermal blasting center.

[0010] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention is the first to systematically reveal and determine the existence of cryptovolcanic breccia mineralization mechanism in volcanic-intrusive iron deposits. Moreover, this mechanism, combined with the traditional magma intrusion and hydrothermal alteration mineralization mechanism, forms high-quality ore bodies, filling the gap in the research on the mineralization mechanism of this type of deposit.

[0011] 2. By combining the correspondence between the characteristics of the rock pipe ring revealed by underground geology and the radial cleavage on the surface, the geological characteristics of cryptovolcanic breccia mineralization can be intuitively and quickly preliminarily determined, providing a solid geological basis for subsequent in-depth analysis.

[0012] 3. By employing LA-ICP-MS micro-area compositional analysis and sulfur isotope testing, combined with multi-component genetic discrimination diagrams, the source region of iron was traced, which can accurately verify the correlation between cryptovolcanic breccia mineralization and deep magmatic activity, and clarify the material source of this mineralization mechanism.

[0013] 4. A systematic index system for identifying ore body characteristics has been established, which can effectively distinguish between three mechanisms: cryptovolcanic breccia mineralization, magma intrusion mineralization, and hydrothermal alteration mineralization, making the judgment results more accurate and reliable.

[0014] 5. This determination method has significant practical application value. It can directly guide the delineation of prospecting target areas in the boundary region of volcanic-intrusive iron ore deposits, provide theoretical support for the analysis of ore body occurrence conditions, and help optimize mining schemes, thereby reducing waste rock mixing rate and improving ore recovery rate and resource utilization rate. Attached Figure Description

[0015] Figure 1 This is a flowchart of the determination method of the present invention; Figure 2 This is a sketch of the distribution of the cryptovolcanic breccia ring zone in the 27-12 trench at the -540m level in the example. Figure 3 This is a diagram illustrating the genetic identification of magnetite TiO2-Al2O3-(MgO+MnO) in the examples; Figure 4 This is a diagram showing the correspondence between the radial cleavage on the surface and the location of the underground cryptovolcanic breccia pipe in the example. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figures 1 to 4 The present invention provides a technical solution: A method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes includes the following steps: S1. Underground Geological Feature Exploration: Geological logging will be conducted on underground tunnels and exploration pits at the mining boundary of the volcanic-intrusive iron ore deposit to investigate the presence of cryptovolcanic breccia pipes. These cryptovolcanic breccia pipes are distributed in a ring around the hydrothermal blast center, consisting of, from the inside out, a blast breccia zone, a breccia zone, and a seismically fractured zone. Simultaneously, the presence of radial cleavage on the deposit surface will be investigated, and it will be determined whether the planar positions of the surface radial cleavage correspond to the planar positions of the underground cryptovolcanic breccia pipes. If the aforementioned ring-shaped cryptovolcanic breccia pipes are found underground, and the surface radial cleavage corresponds to the position of the underground pipes, then the deposit is preliminarily determined to possess the geological characteristics of cryptovolcanic breccia mineralization.

[0018] S2. Magnetite Geochemical Testing and Iron Source Tracing: Magnetite samples were collected from cryptovolcanic breccia pipes, and LA-ICP-MS micro-area compositional analysis and sulfur isotope analysis were performed on the samples. The genetic type of magnetite was analyzed using multi-component genetic discrimination diagrams of TiO2-Al2O3-(MgO+MnO), Al+Mn-Ti+V, and Ti-Ni / Cr. Combined with the sulfur isotope test results, it was determined whether the sulfur source was a mixed source of deep crust / upper mantle and Triassic marine gypsum-sulfur. If the micro-area compositional characteristics of magnetite are concentrated in volcanic / magmatic regions, and the sulfur source is a mixed source of deep and marine gypsum-sulfur, with consistent Cr content indicating co-originating iron, then the iron in the magnetite is determined to originate from a deep magmatic system, thus verifying the correlation between cryptovolcanic breccia mineralization and deep magma.

[0019] S3. Ore Body Characteristic Identification and Verification: Observe the morphology, occurrence, occurrence elevation, and scale of the ore body within the cryptovolcanic breccia pipe to determine whether it is highly consistent with the morphology, occurrence, occurrence elevation, and scale of the cryptovolcanic breccia pipe. Simultaneously, identify the crystal form, ore-rock boundary characteristics, and grade distribution characteristics of magnetite within the ore body. If the magnetite has a coarse-grained structure, a clear ore-rock boundary without gradation, and a grade distributed in a ring-like pattern with a significantly higher grade near the hydrothermal blast center, then the ore body characteristics of cryptovolcanic breccia mineralization are verified.

[0020] S4. Differentiation and Final Determination of Mineralization Mechanisms: Establish an index system for identifying ore body characteristics based on cryptovolcanic breccia mineralization mechanisms, magma intrusion, and hydrothermal alteration. Effective differentiation of these three mineralization mechanisms is achieved through index comparison. If step 1 preliminarily determines the presence of cryptovolcanic breccia mineralization geological characteristics, step 2 verifies that the iron originates from deep magma and is associated with cryptovolcanic breccia mineralization, and step 3 verifies the ore body characteristics of cryptovolcanic breccia mineralization, then the volcanic-intrusive iron deposit is ultimately determined to possess a cryptovolcanic breccia mineralization mechanism. Furthermore, this mechanism, combined with magma intrusion and hydrothermal alteration mineralization mechanisms, forms a high-quality ore body.

[0021] Furthermore, the test indicators for LA-ICP-MS micro-area composition analysis in step S2 include the content and ratio of elements such as TiO2, Al2O3, MgO, MnO, Ti, V, Ni, Cr, Sn, and Ga.

[0022] Furthermore, in the ore body feature identification index system described in step 4: The characteristics of cryptovolcanic breccia mineralization are as follows: the magnetite has a coarse-grained crystalline structure, the ore-rock boundary is clear and there are no signs of hydrothermal alteration, the ore body morphology / occurrence / occurrence elevation / scale is consistent with the breccia pipe, the grade is distributed in a ring-like pattern and there are high-grade anomalies near the blasting center.

[0023] The characteristics of magma intrusion mineralization are: magnetite has a fine- to medium-grained structure, veins intrude and are distributed along fractures, and the grade is relatively uniform.

[0024] The characteristics of hydrothermal alteration mineralization are: the boundary between ore and rock shows signs of gradual change, magnetite has a medium-grained texture, and a large number of hydrothermal alteration minerals are associated with it, with grade showing a gradual distribution.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment takes a volcanic-intrusive iron deposit in the Luzong volcanic rift basin as an example.

[0026] When the main ore body of this deposit is mined to its boundary, the thickness, dip, and strike of the ore body undergo abrupt changes, exhibiting characteristics distinctly different from the original gently dipping main ore body. The mineralization mechanism is determined using the method of this invention, with the following steps: S1. Underground Geological Characteristics Exploration: Geological logging was conducted in the 27-12, 29-12, and 31-12 trench exploration tunnels of the 110 connecting roadway in the southern part of the -540m section of this iron deposit. Cryptovolcanic breccia pipes were discovered within these tunnels. These pipes are distributed in a ring around the hydrothermal blast center, consisting of, from the inside out, a blast breccia zone, a fractured rock zone, and a seismically fractured rock zone. Simultaneously, radial cleavage was found at the surface boundary of the deposit, and its planar position corresponds to the planar position of the cryptovolcanic breccia pipe in the -540m section underground. Based on this, it is preliminarily determined that this deposit possesses the geological characteristics of cryptovolcanic breccia mineralization.

[0027] S2. Magnetite Geochemical Testing and Iron Source Tracing: Dense massive magnetite samples and pyrite-magnetite samples were collected from cryptovolcanic breccia pipes for LA-ICP-MS micro-area compositional analysis and sulfur isotope analysis. Test parameters included TiO2, Al2O3, MgO, MnO, Ti, V, Ni, Cr, Sn, and Ga. The test data were then substituted into genetic discriminant diagrams for TiO2, Al2O3-(MgO+MnO), Al+Mn-Ti+V, and Ti-Ni / Cr. Results showed that the compositional characteristics of the dense massive magnetite samples were concentrated in volcanic and magmatic regions; the magnetite in the pyrite-magnetite samples exhibited hydrothermal origin characteristics due to later metasomatism. Sulfur isotope analysis indicated that the sulfur source was a mixed source of deep crust / upper mantle and Triassic marine gypsum-sulfur. Furthermore, the Cr content in the samples was consistent and did not decrease gradually with the precipitation of magnetite, indicating that the iron originated from the same deep magmatic system, thus verifying the correlation between cryptovolcanic breccia mineralization and deep magma.

[0028] S3. Ore Body Characteristic Identification and Verification: Observation revealed that the morphology, occurrence, occurrence elevation, and scale of the ore body within the cryptovolcanic breccia pipe were completely consistent with those of the pipe. The magnetite in the ore body exhibited a coarse-grained crystalline structure, with a clear ore-rock boundary and no signs of gradual alteration due to hydrothermal alteration. The grade was distributed in a ring-like pattern. Notably, the highest grade of magnetic iron (mFe) near the hydrothermal blast center reached 51.60%, significantly higher than the average grade of the deposit. These characteristics are consistent with the ore body characteristics of cryptovolcanic breccia mineralization, thus completing further verification.

[0029] S4. Differentiation and Final Determination of Mineralization Mechanisms: By comparing the ore body characteristic identification indicators of cryptovolcanic breccia mineralization, magma intrusion mineralization, and hydrothermal alteration mineralization, it was found that the deposit exhibits characteristics of all three mineralization mechanisms simultaneously. Based on the determination and verification results of the above steps, it was finally determined that this volcanic-intrusive iron deposit possesses a cryptovolcanic breccia mineralization mechanism. Specifically, after the coarse-grained magnetite crystallized in the deep source layer, it filled the breccia fissures through cryptovolcanic activity to form the ore body. This mechanism, combined with the original magma intrusion and hydrothermal alteration mineralization mechanisms, jointly formed the high-quality ore body in the boundary area.

[0030] Implementation Results: After clarifying the metallogenic regularity of the boundary area of ​​the deposit using the method of this invention, the mine was guided to carry out targeted prospecting work in the distribution area of ​​cryptovolcanic breccia pipes, effectively delineating the distribution range of high-quality ore bodies. Simultaneously, the mining plan was optimized based on the judgment results, successfully increasing the recovery rate of the boundary ore body by more than 25%, significantly improving mining efficiency and resource utilization.

[0031] The method of this invention is applicable to all volcanic-intrusive iron deposits in the Luzong volcanic rift basin and those with similar geological backgrounds. In practical applications, the combination of LA-ICP-MS micro-area composition test indicators and genetic discrimination diagrams can be adjusted according to the specific geological background of the deposit. Furthermore, magnetic iron grade data from exploration boreholes can be used to help verify the location of hydrothermal blast centers (typically, the section with the highest magnetic iron grade corresponds to the vicinity of the blast center), thereby further improving the accuracy of mineralization mechanism determination.

[0032] For some deposits where no radial cleavage has been found on the surface, if a cryptovolcanic breccia pipe with zonal distribution is clearly exposed underground, and geochemical testing and ore body characteristic identification verify that it conforms to the mineralization characteristics of cryptovolcanic breccia, it can still be determined that the deposit has a cryptovolcanic breccia mineralization mechanism.

[0033] Figure 3 shows the genetic discrimination diagram of magnetite TiO2-Al2O3-(MgO+MnO) in the example: 1) Genetic identification diagram of TiO2-Al2O3-(MgO+MnO) magnetite; I: accessory mineral type, II: magmatic type, III: volcanic type, IV: contact metasomatic type, V: skarn type, VI: sedimentary metamorphic type; 2). Comparison of Sn-Ga magnetite content from different origins; 3). Diagram illustrating the genetic identification of magnetite (Al+Mn-Ti+V); 4). Magnetite Ti-Ni / Cr.

Claims

1. A method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes, characterized in that, Includes the following steps: S1. Underground geological feature exploration: Geological logging of underground rock tunnels and exploration pits at the mining boundary of volcanic-intrusive iron ore deposits, and exploration to investigate whether there are cryptovolcanic breccia pipes. The cryptovolcanic breccia pipes are distributed in a ring around the hydrothermal blasting center, and from the inside out are the blasting breccia zone, the fractured rock zone, and the seismic fractured rock zone. At the same time, investigate whether there are radial cleavages on the surface of the deposit, and determine whether the planar position of the radial cleavages on the surface corresponds to the planar position of the underground cryptovolcanic breccia pipe; If the above-mentioned cryptovolcanic breccia pipes with the above-mentioned ring distribution are found underground, and the radial cleavage on the surface corresponds to the location of the underground pipes, it is preliminarily determined that the deposit has the geological characteristics of cryptovolcanic breccia mineralization. S2. Magnetite geochemical testing and iron source tracing: Magnetite samples were collected from cryptovolcanic breccia pipes, and LA-ICP-MS micro-area composition analysis and sulfur isotope composition testing were performed on the samples. The genetic types of magnetite are analyzed using multi-component genetic discrimination diagrams of TiO2-Al2O3-(MgO+MnO), Al+Mn-Ti+V, and Ti-Ni / Cr. Based on the sulfur isotope test results, determine whether the sulfur source is a mixed source of deep crust / upper mantle and Triassic marine gypsum sulfur; If the micro-regional compositional characteristics of magnetite are concentrated in volcanic / magmatic regions, and the sulfur source is a mixture of deep-seated and marine gypsum-sulfur sources, and the Cr content is consistent, indicating that the iron is of the same origin, then it is determined that the iron in magnetite originates from a deep magmatic system, verifying the correlation between cryptovolcanic breccia mineralization and deep magma. S3. Identification and verification of ore body characteristics: Observe the shape, occurrence, occurrence elevation and scale of the ore body in the cryptovolcanic breccia pipe, and determine whether it is highly consistent with the shape, occurrence, occurrence elevation and scale of the cryptovolcanic breccia pipe. Simultaneously identify the crystal form, ore-rock boundary characteristics, and grade distribution characteristics of magnetite in the ore body: If the magnetite has a coarse-grained structure, a clear ore-rock boundary without any signs of gradual change, and a grade that is distributed in a ring-like pattern with a significantly higher grade near the hydrothermal explosion center, then the mineralization characteristics of the cryptovolcanic breccia are verified. S4. Differentiation and final determination of mineralization mechanisms: Establish an index system for identifying ore body characteristics of cryptovolcanic breccia mineralization, magma intrusion, and hydrothermal alteration mineralization mechanisms, and differentiate the three mineralization mechanisms through index comparison. If step S1 preliminarily determines the presence of cryptovolcanic breccia mineralization geological characteristics, step S2 verifies that the iron originates from deep magma and is associated with cryptovolcanic breccia mineralization, and step S3 verifies the ore body characteristics of cryptovolcanic breccia mineralization, then it is finally determined that the volcanic-intrusive iron deposit has a cryptovolcanic breccia mineralization mechanism, and this mechanism, combined with the magma intrusion and hydrothermal alteration mineralization mechanisms, forms a high-quality ore body.

2. The method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes according to claim 1, characterized in that, The test indicators for LA-ICP-MS micro-area composition analysis in step S2 include the content and ratio of elements such as TiO2, Al2O3, MgO, MnO, Ti, V, Ni, Cr, Sn, and Ga.

3. The method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes according to claim 1, characterized in that, In the ore body characteristic identification index system described in step S4, the characteristics of cryptovolcanic breccia mineralization are as follows: magnetite has a coarse-grained crystalline structure, clear ore-rock boundary with no signs of hydrothermal alteration, ore body morphology / occurrence / occurrence elevation / scale consistent with the breccia pipe, grade distributed in a ring-like pattern with anomalies of high grade near the blasting center; the characteristics of magma intrusion mineralization are as follows: magnetite has a fine- to medium-grained structure, veins intruding along fractures, and relatively uniform grade; the characteristics of hydrothermal alteration mineralization are as follows: The boundary between the ore and rock shows signs of gradual change. The magnetite has a medium-grained texture and is accompanied by a large number of hydrothermal alteration minerals. The grade is distributed in a gradual manner.

4. The method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes according to claim 1, characterized in that, For deposits where no radial cleavage is found on the surface, if a cryptovolcanic breccia pipe with zonal distribution is clearly exposed underground, and the mineralization characteristics of cryptovolcanic breccia are verified by steps S2 and S3, it can still be determined that the deposit has a cryptovolcanic breccia mineralization mechanism.

5. The method for determining the mineralization mechanism of volcanic-intrusive iron deposits based on cryptovolcanic breccia pipes according to claim 1, characterized in that, In step S3, the magnetic iron grade data from the exploration boreholes are used to help verify the location of the hydrothermal blast center. The borehole section with the highest magnetic iron grade is the area near the hydrothermal blast center.

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