Physical simulation experimental method for controlling Pb mineralization distribution by inverted folding deformation process

Abstract

This invention discloses a physical simulation experimental method for controlling Pb mineralization distribution during the overturned fold deformation process. Belonging to the interdisciplinary field of structural geology and mineral geology, this method achieves accurate simulation of tectonic deformation and Pb mineralization processes through multi-dimensional similarity matching based on geometry, kinematics, dynamics, and time, combined with multi-parameter synergistic control and full-dimensional monitoring. It can intuitively reveal the coupling mechanism between overturned fold deformation and Pb mineralization distribution, explore the mineralization control mechanism of tectonic deformation under multi-physics field conditions, and establish an overturned fold structure prospecting model based on the actual geological example of the Maoping lead-zinc deposit. This clarifies the prospecting direction and delineates favorable exploration target areas for deep-edge exploration of lead-zinc deposits.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary research field of structural geology and mineral geology, and specifically relates to a physical simulation experimental method for controlling the distribution of Pb mineralization during the overturned folding deformation process. Background Technology

[0002] The Maoping lead-zinc deposit in northeastern Yunnan is located on the southwestern margin of the Yangtze Block. It is a highly representative super-large lead-zinc deposit within the Sichuan-Yunnan-Guizhou polymetallic lead-zinc ore cluster in my country. The unique tectonic setting of this region provided key dynamic conditions for the formation of the deposit, with its tectonic ore-controlling characteristics being particularly significant. The deposit as a whole is controlled by the NE-trending Maoping compressional-torsional fault and the hanging wall Maomaoshan anticline, and the mineralization process and tectonic mechanical evolution show a close coupling relationship. Field exploration and specialized studies have confirmed that mineralization is enriched within the NE-trending inter-layer fault zone on the overturned wing of the overturned fold. This area is a stress transition zone with good material exchange conditions, making it a key site for the precipitation of ore-forming materials, ultimately forming a typical "tectonic ore-controlling" model.

[0003] Currently, research on the relationship between folds and mineralization distribution in the Maoping lead-zinc deposit has comprehensively utilized diverse techniques, including detailed geological mapping, structural analysis, geophysical exploration, geochemical analysis, fluid inclusion testing, and isotope dating, accumulating rich macroscopic geological data and preliminarily clarifying the spatial correlation between fold morphology and mineralization distribution. However, existing research still has limitations: a multifunctional visualization experimental system integrating tectonic deformation, fluid migration, mineral transport, and precipitation processes has not yet been developed, resulting in insufficient quantitative research on the fold-controlled mineralization mechanism and the inability to dynamically track and summarize the patterns of Pb mineralization migration and enrichment during the evolution of overturned folds. Summary of the Invention

[0004] Addressing the core limitation in tectonic ore-controlling research of the Maoping lead-zinc deposit in northeastern Yunnan—the inability to quantitatively analyze the driving mechanism of Pb mineralization migration and enrichment through the dynamic evolution of folds from initial bending to complete inversion—and solving the problem of insufficient quantitative research on fold-controlled ore-controlling mechanisms, this invention provides a physical simulation experimental method for controlling Pb mineralization distribution during the deformation process of inverted folds. Through multi-dimensional similarity matching of geometry, kinematics, dynamics, and time, combined with multi-parameter synergistic control and full-dimensional monitoring, it achieves accurate simulation of tectonic deformation and Pb mineralization processes. This method can intuitively reveal the coupling mechanism between inverted fold deformation and Pb mineralization distribution, providing experimental technical support and theoretical basis for target area prediction in mineral resource exploration.

[0005] This invention constructs an experimental system integrating multi-similarity matching, multi-parameter control, multi-system linkage, and multi-dimensional monitoring to accurately simulate the complete dynamic evolution of overturned folds from initial bending to complete overturning. It tracks the migration path and enrichment patterns of Pb mineralization in real time, quantitatively revealing the coupling mechanism between tectonic deformation and Pb mineralization distribution. This provides experimental evidence and theoretical support for Pb exploration in overturned fold areas. At the same time, it establishes a tectonic prospecting model based on actual deposit examples, clarifying the prospecting direction for deep-side exploration of deposits.

[0006] This invention achieves its objectives through five core steps: precise proportioning of experimental materials, construction of a multi-system integrated experimental device, comprehensive initial data acquisition, dynamic coupling control of tectonic deformation and mineralization injection, and comprehensive analysis of experimental data. The technical details of each step strictly match the experimental requirements while adhering to the principles of geometric, kinematic, dynamic, and temporal similarity to ensure consistency between the experimental simulation and the geological prototype. Specifically: 1. Proportioning and preparation of experimental materials The experimental materials were categorized into three types based on their function: stratigraphic simulation materials, fault / fold simulation materials, and Pb mineralization simulation fluids. The parameters and selection of each material strictly matched the physicochemical properties of the geological prototypes while also meeting the experimental similarity requirements. The specific proportions and preparation methods are as follows: Stratigraphic simulation materials: Based on the lithological characteristics of the overturned fold zone (Maomaoshan anticline of Maoping deposit), materials matching the geological prototype were selected layer by layer, strictly adhering to the requirements for parameters such as grain size, bulk density, and hardness: grain size of 0.1-0.55mm and bulk density of 1.5-1.7g / cm³ were selected. 3 Quartz sand simulates brittle rock layers, 0.05-0.1mm microglass beads simulate transition layers, silica gel with a Shore A hardness of 20-40 simulates plastic layers, and clay with a montmorillonite content >80% simulates argillaceous interlayers. All materials ensure stable mechanical properties, with no abnormal fluctuations in permeability or adhesion, accurately replicating the lithology and mechanical characteristics of the geological prototype strata and achieving dynamic similarity.

[0007] Fault / Fold Simulation Materials: A layered stainless steel mesh is used as the boundary framework for the fault and fold layers, with the interlayer filled with 0.1-0.5mm of quartz sand. By adjusting the quartz sand filling parameters, the permeability and mechanical characteristics of the geological prototype's faults and folds are matched, meeting the requirements of dynamic similarity and ensuring that the simulation laws of tectonic deformation and fluid migration are consistent with the geological prototype. Simultaneously, a mixture of clay and quartz sand is prepared to fill the gaps above the fault layers and between the fold layers and the box structure, ensuring the integrity and stability of the structural model.

[0008] Pb mineralization simulation fluid: An aqueous solution containing 0.01-0.02 mol / L PbCl2, 1-3 mol / L NaCl, and pH 3.8-4.0 is used as the ore-forming fluid and is precisely prepared in a storage tank. The viscosity of the ore-forming fluid is 1-10 mPa·s, and the density is 1.0-1.2 g / cm³. 3 The physicochemical parameters are consistent with those of the low-temperature hydrothermal ore-forming fluids in the Maoping deposit; a NaHS layer was pre-placed within the quartz sand of the fold layer to simulate the Pb content during the ore-forming process. 2+ With S 2- The chemical reaction reduces the actual Pb mineralization precipitation process. 2. Construction of Multi-System Integration Experimental Device An integrated experimental device for "tectonic deformation-mineralization injection-monitoring and analysis" was constructed. The device consists of a box-type assembly, a tectonic deformation system, a mineralization injection system, and a multi-dimensional monitoring system. The design and construction of each system strictly match the experimental requirements, and the connection of components and parameter settings ensure the accuracy and stability of the experiment, as detailed below: Box assembly: The main frame is a high-strength steel fixed box. The front of the box is equipped with a pressure-resistant and corrosion-resistant transparent box wall (light transmittance ≥90%, pressure resistance 5MPa) for visual observation during the experiment. The box is laid in layers according to the design requirements, including the ground layer, the fracture layer, and the fold layer. The fold layer is laid in an antislope shape, with one end connected to the fracture layer and the other end in close contact with the push plate on the right side of the box. The gap between the fracture layer and the fold layer and the box is filled with a mixture of clay and quartz sand and compacted.

[0009] Deformation system: The core adopts a high-precision servo push rod. One end of the push rod is fixed on the bracket, and the other end, the piston rod, slides through the box and is fixed to the push plate. The push rod displacement control accuracy is ±0.01mm, and the rate adjustment can be achieved from 0.01 to 0.1cm / min. The maximum compression is 200mm. The axial pressure can be limited according to the geological prototype tectonic stress characteristics to achieve motion and dynamic similarity matching.

[0010] Mineralization injection system: Composed of a storage tank, a metering pump, and corrosion-resistant inlet and outlet pipes; the perforated end of the inlet pipe is located at the right end of the fracture layer, 4-7 cm away from the push plate, with several through holes in the pipe body, the diameter of which is 1-3 mm and the spacing between the holes is 5-15 mm, to ensure uniform fluid injection, and the other end is connected to the storage tank through the metering pump; one end of the outlet pipe is located inside the right end of the fold layer, and the other end is connected to the pre-set outlet of the tank; the metering pump has a flow control accuracy of ±0.2%, and can achieve an injection rate adjustment of 0.1-10 mL / min; the storage tank is equipped with a concentration detector (accuracy ±0.1%) and pH and Eh monitors to ensure stable ore-forming fluid parameters.

[0011] The multi-dimensional monitoring system consists of a high-speed imaging system, mechanical testing equipment, an online concentration analyzer, a pH / Eh monitor, and a high-precision flow sensor. The high-speed imaging system, with a frame rate of 500fps, is aligned with the transparent tank wall to record tectonic deformation and mineralized fluid movement. The mechanical testing equipment collects mechanical parameters of the formation and tectonic zones. The online concentration analyzer (accuracy ±0.1%) is deployed at the inlet and outlet to monitor Pb in real time. 2+ The system includes NaCl concentration monitoring; pH / Eh monitoring meters for measuring fluid physicochemical parameters; flow sensors (accuracy ±0.05 g / min) installed at the metering pump outlet and liquid outlet to collect injection volume and flow rate in real time; all monitoring devices are linked in sequence via a programmable logic controller (PLC), and monitoring data (sampling frequency 1 Hz) is transmitted in real time to a dedicated analysis platform to ensure the continuity and accuracy of data acquisition. 3. Experimental model design and similarity matching An experimental model was designed based on the prototype of the inverted fold geological body. The geometric similarity between the model and the prototype was determined at a scale of 1:500-1:5000, laying the foundation for matching motion, dynamics, and temporal similarity. By accurately selecting and proportioning the materials of the strata, fault layers / fold layers, the mechanical characteristics of the geological prototype were replicated to achieve dynamic similarity. By controlling the movement rate of the push rod and the injection rate of the ore-forming fluid, the rate characteristics of the structural deformation and ore-forming fluid migration of the geological prototype were matched to achieve motion similarity. By controlling the temporal relationship between structural deformation and mineralization fluid injection, the tectonic evolution and mineralization process of the geological prototype were matched to achieve temporal similarity.

[0012] 4. Initial data collection across all dimensions Before the experiment officially begins, complete the full-dimensional data collection and archiving of the model's initial state to provide benchmark data for subsequent experimental analysis: A high-speed imaging system was used to capture and record the stratigraphic layer structure, spatial distribution of fault and fold layers, and material distribution characteristics of various simulated materials in the initial state of the model, to verify the geometric similarity matching effect. Mechanical parameters such as initial compressive strength, bulk density, and permeability of strata and structural zones are collected using mechanical testing equipment, providing a basis for accurate matching of dynamic similarity. The initial Pb of the ore-forming fluid in the storage tank was collected using an online concentration detector. 2+ The concentration of NaCl and the initial pH and Eh values ​​of the fluid were measured using a pH / Eh monitor. All initial data collected are recorded, organized, and archived in a unified manner. After verifying the completeness of the data and confirming that there are no missing or abnormal data, the formal experimental phase begins.

[0013] 5. Dynamic Coupling Experiment Control of Tectonic Deformation and Mineralization Injection This experiment employed two modes: fluid injection and synchronous injection-deformation, to simulate the interaction between structures and fluids at different time points. The study investigated the migration, enrichment, and precipitation processes of Pb ore fluids, the synergistic ore-controlling effect of structures and fluids, and the real-time coupling effect between structures and ore-forming fluids. The experimental procedures are as follows: Open the push rod and adjust the movement speed of its piston rod to 0.01-0.1 cm / min. The axial pressure of the push rod can be limited according to the stress characteristics of the geological prototype structure, and the dynamics and motion similarity can be precisely matched. The metering pump is turned on in the experimental mode to deliver the ore-forming fluid in the storage tank to the fracture layer at a rate of 0.1-10 mL / min. In the fluid injection mode, the mineralization fluid is injected first and then the tectonic deformation is carried out. In the synchronous injection-deformation mode, the fluid injection rate is matched with the tectonic deformation rate to further improve the motion similarity matching. By pushing the push plate 3-5cm with the push rod, the complete deformation process of the inverted fold from initial bending to complete inversion is simulated. During the experiment, the structural deformation characteristics, mineralized fluid migration path and dynamic changes of various parameters are recorded in real time by a multi-dimensional monitoring system. After the experiment, the folded structure was cross-sectionally processed and multiple samples were taken from different structural parts (steep limbs, gentle limbs, core, turning point, interlayer fault zone, etc.) to analyze the content and distribution characteristics of Pb mineralization in the samples.

[0014] 6. Experimental data processing and mineral exploration model establishment By combining real-time monitoring data and profile sampling results from the experimental process, a comprehensive analysis was conducted using modeling software and data statistics software. The monitoring data were sorted, screened and statistically analyzed, parameter change curves were plotted, and the migration law of Pb mineralization material during the structural deformation process was quantitatively analyzed. By combining image data from a high-speed imaging system, a visual description of the mineralization process can be achieved, the mineralization enrichment characteristics of different structural parts of the overturned folds can be clarified, and the relationship between structure and mineralization at the three-dimensional scale can be analyzed. This study explores the mineralization control mechanism of tectonic deformation under multi-physics field conditions and quantitatively presents the correspondence between the mineralization enrichment coefficient and the fault activity intensity of different parts of the overturned fold. Based on actual deposit examples such as the Maoping lead-zinc deposit, the rationality and reliability of the experimental results were verified. Finally, a structural prospecting model of ore-controlling inverted folds was established to determine the prospecting direction and favorable exploration targets for the deep edge exploration of the deposit.

[0015] The beneficial effects of this invention are: High simulation accuracy: Through geometric, motion, dynamic and temporal similarity matching, combined with the precise ratio of experimental materials and multi-system linkage control, high-precision simulation of inverted fold morphology and Pb mineralization distribution is achieved, solving the problem of large deviation between traditional experimental methods and actual geological conditions, and the experimental results are more valuable for reference. The dynamic mechanism is clear: Through two experimental modes, fluid injection and synchronous injection-deformation, the dynamic coupling simulation of tectonic deformation and mineralization injection is realized, clearly presenting the migration path and enrichment law of Pb mineralization material in different evolution stages of overturned folds (initial bending → local overturning → complete overturning), elucidating the ore-controlling mechanism of the overturned wing detachment space and stress concentration zone at the turning end, and filling the gap in the study of tectonic-fluid coupling dynamic processes.

[0016] Significant exploration application value: It quantitatively reveals the coupling relationship between tectonic deformation and Pb mineralization distribution, provides key tectonic parameters for mineralization enrichment in various parts of overturned folds, and the tectonic prospecting model established in conjunction with actual deposits can directly provide clear prospecting directions for the selection of Pb exploration target areas and the exploration of deep and marginal parts of deposits.

[0017] The method is highly versatile: the experimental setup adopts a modular design, which can flexibly adjust the model scale, fault dip angle, initial anticline morphology, stratigraphic lithology ratio, and fluid parameters according to the structural characteristics of different mineralized areas. It is suitable for Pb deposit research in overturned fold areas of different orogenic belts. At the same time, by adjusting the material ratio and experimental parameters, it can be extended to the simulation of polymetallic mineralization such as Cu and Au, providing a standardized experimental method for mineral exploration in complex structural areas.

[0018] The monitoring system is comprehensive: it enables visualization and datafication of the experimental process, and real-time transmission and storage of monitoring data, providing complete and accurate data support for the quantitative analysis of the ore-controlling mechanism. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the experimental apparatus used in the method of this invention; Figure 2 This is a partial structural diagram of the experimental apparatus used in the method of the present invention; Figure 3 These are photos of a fluid filling experiment; Figure 4 Photographs of structural deformation and fluid filling experiments; In the diagram, 1-box body, 2-stratum, 3-fracture layer, 4-fold layer, 5-push plate, 6-push rod, 7-inlet pipe, 8-outlet pipe, 9-storage tank, 10-outlet. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments. This embodiment takes the simulation of the Pb mineralization enrichment mechanism during the overturning process of the Maomaoshan anticline in the Maoping lead-zinc deposit as an example. The experimental parameters are all selected within the scope of the claims of the present invention and are not intended to limit the scope of protection of the present invention. Example 1: Fluid filling experiment of a pendulum model This study addresses the core issue of the migration patterns and enrichment characteristics of Pb mineralization in different structural locations within the static tectonic morphology of the Maomaoshan overturned anticline in the Maoping lead-zinc deposit. It reveals the guiding and enrichment control effects of different locations within the overturned anticline, such as the steep limb, gentle limb, core, and interlayer fault zones, on the migration of mineralized fluids. The study clarifies the main structural locations controlling mineralization under the static tectonic pattern of the overturned anticline, providing experimental evidence for mineralization exploration in the exposed overturned fold areas of the deposit.

[0021] 2. For example Figure 1-2 As shown, within the box 1, strata 2 are laid in layers according to lithology. The layering method is as follows from bottom to top: a clay interlayer simulating argillaceous interlayer with montmorillonite content >80%, 2cm thick; a plastic layer simulating silica gel with a hardness of Shore A 30, 3cm thick; a transition layer simulating 0.05-0.1mm microglass beads, 2cm thick; and a brittle rock layer simulating quartz sand with a particle size of 0.2-0.5mm and a bulk density of 1.6g / cm³, 4cm thick. After each layer is laid, it is lightly pressed and leveled to ensure clear bedding interfaces. Then, fracture layer 3 is laid on strata 2. Fold layer 4 is arranged in an anticlinal shape according to the prototype of the Maomaoshan anticline. One end is connected to fracture layer 3, and the other end is in close contact with the push plate 5 on the right side of box 1. Both fracture layer 3 and fold layer 4 are stainless steel mesh with interlayers, and the interlayers are filled with 0.1-0.3mm... The quartz sand in the folded layer 4 is pre-filled with a NaHS layer to simulate the sulfur source layer in the mineralization process; one end of the push rod 6 is fixed to the support, and the other end of the piston rod slides through the box and is fixed to the push plate 5; the area above the fractured layer 3 and between the folded layer 4 and the box is filled with a mixture of clay and quartz sand (1:2) and compacted to ensure the integrity and stability of the structural model and to avoid leakage from cracks during the experiment; the perforated end of the liquid inlet pipe 7 is set at the right end of the fractured layer 3 and 5 cm away from the push plate 5, and the other end is connected to the storage tank 9 through a metering pump; one end of the liquid outlet pipe 8 is set inside the right end of the folded layer 4, and the other end is connected to the liquid outlet 10 on the box 1; several through holes are evenly opened at the perforated end of the liquid inlet pipe 7, with a hole diameter of 2 mm and a hole spacing of 10 mm, to ensure that the mineralization fluid is evenly injected into the fractured layer; the storage tank is filled with 0.015 mol / L PbCl2 and 2 mol / L An aqueous solution of NaCl with a pH of 3.9 was used as the ore-forming fluid, with a viscosity of 5 mPa·s and a density of 1.0 g / cm³. 3 ; This embodiment is a static swing model experiment, using a pure fluid injection mode, with no structural deformation operations throughout the process, and the model shape remains fixed at all times. The specific operation procedure is as follows: After completing the pendulum model construction and device assembly of the inverted anticline model, full-dimensional initial data acquisition was carried out: a high-speed imaging system with a frame rate of 500fps was used to capture and record the stratigraphic layer structure, spatial distribution morphology of fault layers and fold layers, and material distribution characteristics of various simulated materials in the initial state of the model; the initial compressive strength, bulk density, and permeability of the strata and tectonic zones were collected using mechanical testing equipment; and the initial Pb of the ore-forming fluid in the storage tank was collected using an online concentration detector with an accuracy of ±0.1%. 2+ The initial pH and Eh values ​​of the fluid were measured using a pH / Eh monitor, along with the NaCl concentration. All initial data were collected, recorded, and archived. After verifying that there were no missing or abnormal data, the experiment proceeded to the next step.

[0022] The metering pump was turned on, and the ore-forming fluid in the storage tank was delivered to the fracture layer 3 through the inlet pipe 7 at a constant rate of 0.6 mL / min. The multi-dimensional monitoring system was turned on throughout the experiment and monitored continuously for 8 hours, recording the dynamic changes of various parameters in real time. Key monitoring items: migration path and rate of ore fluid in the steep limbs, gentle limbs, and core of the overturned anticline; fluid filling efficiency in the interlayer fracture zone; and Pb concentration at the outlet. 2+ Changes in concentration, pH / Eh value, and precipitation characteristics and mineralization enrichment degree of PbS in different structural locations; The specific parameters and monitoring focus for each monitoring phase are shown in the table below:

[0023] See results Figure 3 As can be clearly observed from the figure: under the static morphology of the overturned anticline, the ore-forming fluids mainly migrate rapidly along fault layer 3 and preferentially converge towards the interlayer fault zone of the steep limb of the overturned anticline. Due to the development of fractures and abundant sulfur sources, this area becomes the core region for PbS precipitation, with a mineralization enrichment coefficient significantly higher than other areas; only a few punctate mineralization bodies are observed on the gentle limb of the overturned anticline, and there is almost no obvious mineralization precipitation in the core; Pb at the outlet... 2+ The concentration of Pb in the slurry decreased rapidly in the first 2 hours of the experiment, leveled off between 2 and 6 hours, and remained relatively stable after 6 to 8 hours, indicating that the concentration of Pb in the slurry was low in the later stages of the experiment. 2+ Pb has been fully deposited in the dominant structural regions and is mobile in the fluid. 2+ The content decreased significantly. This example confirms that the interlayer fault zone on the steep limb of the overturned anticline is the main enrichment site for Pb mineralization under a static tectonic framework.

[0024] Example 2: Experiment on normal anticline morphology with simultaneous deformation and filling To address the core issue of the synergistic ore-controlling mechanism of tectonic deformation and ore-forming fluids during the dynamic evolution of the Maomaoshan anticline in the Maoping lead-zinc deposit from its normal to its overturned state, this study reveals the coupling relationship between different deformation stages of the fold (initial bending, partial overturning, and complete overturning) and ore fluid enrichment. It clarifies the main tectonic stages and locations controlling mineralization enrichment during the dynamic evolution process, providing quantitative experimental evidence for predicting exploration target areas in the deep, unexposed folded areas of the deposit.

[0025] The device in this embodiment is the same as that in embodiment 1. The core difference between the two is that the initial structural morphology of the experiment is a normal anticline, rather than the inverted anticline pre-constructed in embodiment 1; the experimental mode adopts the synchronous injection-deformation mode to realize the real-time coupling of structural deformation and ore-forming fluid injection, rather than the static structural fluid filling mode of embodiment 1. This embodiment adopts the synchronous injection-deformation mode. The operation process is as follows: First, in the box 1, the strata 2, the fracture layer 3 and the fold layer 4 of the normal anticline morphology are laid in the layered manner of embodiment 1. The gap mixture is filled and compacted to construct the initial structural model of the normal anticline. Then, the initial structural morphology of the model, the mechanical parameters of the strata and structural zones, and the physicochemical parameters of the ore-forming fluids are collected and archived in all dimensions. After verifying that the data is correct, the formal experiment is carried out. Simultaneously, push rod 6 and the metering pump were activated to synchronize tectonic deformation and ore-forming fluid injection. The tectonic deformation parameters were set as follows: the initial push rod movement speed was 0.05 cm / min; after the strata exhibited significant initial bending (after 2 hours of experimentation), the speed was increased to 0.08 cm / min. Push rod 6 then pushed push plate 5 to the left of the chamber by 3.5 cm, completely simulating the tectonic evolution process from normal anticline to local overturn to complete overturn. Based on the tectonic stress characteristics of the Maoping deposit prototype, the axial pressure of the push rod was limited to 10-15 MPa to match the dynamic characteristics of the geological prototype. The fluid injection parameters were set as follows: the metering pump and push rod were activated synchronously, and the ore-forming fluid injection rate was kept constant at 0.6 mL / min, precisely matching the tectonic deformation rate and achieving real-time coupling between the structure and the fluid. A multi-dimensional monitoring system was activated throughout the experiment, with all monitoring devices maintaining a sampling frequency of 1 Hz for 8 hours, continuously recording the dynamic coupling process of tectonic deformation and ore fluid migration and enrichment in real time.

[0026] Key monitoring contents: the migration path and enrichment characteristics of mineral fluid in different deformation stages of folds, the compatibility between tectonic deformation rate and mineral fluid filling rate, and the degree of mineralization enrichment and PbS precipitation pattern in different deformation stages.

[0027] The specific parameters and monitoring focus for each monitoring phase are shown in the table below:

[0028] See results Figure 4As can be clearly observed from the figure, the coupling effect of tectonic deformation and ore-forming fluids plays a decisive role in Pb mineralization enrichment, and the degree of mineralization enrichment shows a significant increasing trend with the advancement of fold deformation stages. In the initial bending stage, normal anticlines only show a small number of point-like mineralization bodies at the primary fractures, and the mineralization distribution is scattered. In the local overturning stage, a large number of newly formed fractures develop on the overturned limbs, and the ore fluid rapidly converges to the newly formed fractures. Fine vein-like mineralization bodies appear in the interlayer fault zones, and the mineralization enrichment coefficient increases by more than 60% compared with the initial stage. In the complete overturning stage, the newly formed fractures are completely connected with the primary fractures, forming a complete ore fluid migration-enrichment channel. Large-scale vein-like and network-like mineralization bodies appear in the interlayer fault zones of the overturned limbs, becoming the core area of ​​mineralization enrichment. The mineralization enrichment coefficient in this part is 2.3 times that of the local overturning stage and 4.5 times that of the initial bending stage.

[0029] Simultaneously, it can be observed that when the tectonic deformation rate and the fluid injection rate are precisely matched, there is no significant leakage of the ore fluid, and it can quickly fill the tectonic fractures and complete precipitation, resulting in a significant improvement in mineralization enrichment efficiency. If the two rates are not matched, the ore fluid is prone to premature overflow or insufficient fracture filling, leading to a decrease in the degree of mineralization enrichment. This embodiment confirms that the interlayer fault zone of the overturned limb in the fully overturned stage of the overturned fold is the main controlling enrichment site of Pb mineralization during the dynamic evolution process, and the matching of the rates of tectonic deformation and ore-forming fluid is the key factor for achieving efficient mineralization enrichment.

[0030] Experiment Extension and Explanation Parameter adjustment flexibility: The experimental model scale, initial anticline morphology, fault dip angle, stratigraphic lithology ratio and other parameters can be flexibly adjusted according to the structural characteristics of different mineral deposit exploration areas, so that the experiment is more in line with the actual geological conditions of the study area. Technical improvement directions: A fluid pressure sensor can be added to the experimental device to simulate the dynamic conditions of ore-forming fluids. The experimental model can be optimized by combining actual fluid data from the ore deposit to further improve the accuracy of the experiment. Application Scope Expansion: This method can be directly extended to the study of lead-zinc deposits controlled by similar fault-fold structures. By adjusting the material ratio and fluid parameters, it can be extended to the simulation of structure-controlled mineralization of polymetallic mineralization such as Cu and Au. At the same time, it can be applied to the study of other fluid-related minerals such as oil and gas reservoirs and geothermal resources. By adjusting similar materials, experimental parameters and boundary conditions, it can simulate more types of geological structures such as normal faults, strike-slip faults, and extensional structures and their impact on fluid migration. Technological optimization potential: The results of the physical simulation experiments of this invention can be compared and verified with the results of the numerical simulation by combining numerical simulation technology, so as to complement and improve each other, and further improve the accuracy and reliability of the study on the tectonic control mechanism of mineralization.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. All modifications and optimizations guided by the core ideas of the present invention should be included in the scope of protection.

Claims

1. A physical simulation experimental method for controlling Pb mineralization distribution during inverted folding deformation process, characterized in that, The steps are as follows: (1) Design an experimental model based on the prototype of the inverted fold geological body, determine the geometric similarity between the model and the prototype at a scale of 1:500-1:5000, and at the same time rely on the structural evolution and mineralization law of the geological prototype to lay the foundation for matching the similarity of movement, dynamics and time. Lay the strata (2) in layers in the box (1) according to the actual lithological characteristics of the mineralized area, and then lay the fault layer (3) on the strata (2). The fold layer (4) is arranged in an anticlinal shape, with one end connected to the fault layer (3) and the other end in close contact with the push plate (5) on the right side of the box (1). One end of the push rod (6) is fixed to the bracket, and the other end of the piston rod slides through the box and is fixed to the push plate (5); the top of the fracture layer (3) and the space between the fold layer (4) and the box are filled with a mixture of clay and quartz sand and compacted; the perforated end of the liquid inlet pipe (7) is set at the right end of the fracture layer (3) and 4-7 cm away from the push plate (5), and the other end is connected to the storage tank through a pump; one end of the liquid outlet pipe (8) is set inside the right end of the fold layer (4), and the other end is connected to the liquid outlet on the box (1); the storage tank is filled with an aqueous solution containing 0.01-0.02 mol / L PbCl2, 1-3 mol / L NaCl, and pH 3.8-4.0 as the ore-forming fluid, and the viscosity of the ore-forming fluid is 1-10 mPa·s and the density is 1.0-1.2 g / cm³. 3 ; (2) A high-speed imaging system with a frame rate of 500fps was used to capture and record the stratigraphic layer structure, spatial distribution morphology of fault layers and fold layers, and material distribution characteristics of various simulated materials in the initial state of the model; the initial compressive strength, bulk density, and permeability of the strata and tectonic zones were collected using mechanical testing equipment; and the initial Pb of the ore-forming fluid in the storage tank was collected using an online concentration detector with an accuracy of ±0.1%. 2+ The concentration of NaCl and the initial pH and Eh values ​​of the fluid were measured simultaneously; all the above initial data were collected, recorded and archived. (3) Open the push rod (6) and adjust the movement speed of its piston rod to 0.01-0.1cm / min. The axial pressure of the push rod can be limited according to the stress characteristics of the geological prototype structure to match the dynamics and motion similarity. The pump is turned on simultaneously, and the ore-forming fluid in the storage tank is transported to the fracture layer (3) through the inlet pipe (7) at a rate of 0.1-10 mL / min. The compatibility between the fluid injection rate and the structural deformation rate is adjusted to further improve the motion similarity matching. The pusher plate (5) is pushed by the pusher rod (6) to move directionally by 3-5 cm to simulate the complete deformation process of the overturned fold from initial bending to complete overturning. The experiment adopts two modes: fluid injection and synchronous injection-deformation. By adjusting the temporal relationship between structural deformation and ore-forming fluid injection, the tectonic evolution and mineralization process of the geological prototype are matched, thus realizing the goal of achieving the desired result. Temporal similarity was used to study the migration, enrichment, and precipitation processes of Pb ore fluids, the synergistic ore-controlling effect of structures and fluids, and the real-time coupling effect of structures and ore-forming fluids. After the experiment, cross-sectional processing of the fold structure was performed and samples were taken from different structural parts. Combined with the monitoring data of the experimental process, the occurrence relationship between structures and mineralization at the three-dimensional scale was analyzed using modeling software and data statistics software. The ore-controlling mechanism of structural deformation under multi-physics field conditions was explored. Finally, a structural prospecting model of ore-controlling inverted folds was established based on actual ore deposit examples to determine the prospecting direction and favorable exploration targets for the deep edge exploration of ore deposits.

2. The physical simulation experimental method for controlling Pb mineralization distribution during the inverted folding deformation process according to claim 1, characterized in that: The front of the box (1) is a transparent box wall, which is used for visual observation of the experimental process.

3. The physical simulation experimental method for controlling Pb mineralization distribution during the inverted folding deformation process according to claim 1, characterized in that: The fracture layer (3) and the fold layer (4) are both stainless steel mesh with interlayers, and the interlayers are filled with 0.1-0.5 mm of quartz sand. The quartz sand in the fold layer (4) is pre-filled with a NaHS layer. By matching the permeability and mechanical characteristics of the geological prototype fracture and fold zone through this structure, the dynamic similarity requirements are met, ensuring that the simulation law of structural deformation and fluid migration is consistent with the geological prototype.

4. The physical simulation experimental method for controlling Pb mineralization distribution during the inverted folding deformation process according to claim 1, characterized in that: The inlet pipe (7) has several through holes at the perforated end, with a hole diameter of 1-3 mm and a hole spacing of 5-15 mm.

5. The physical simulation experimental method for controlling Pb mineralization distribution during the inverted folding deformation process according to claim 1, characterized in that: The simulation materials for the strata (6) were selected according to lithological characteristics. Among them, quartz sand with a particle size of 0.1-0.55 mm and a bulk density of 1.5-1.7 g / cm³ simulated brittle rock layers, 0.05-0.1 mm micro glass beads simulated transition layers, silica gel with a hardness of shore A 20-40 simulated plastic layers, and clay with a montmorillonite content of >80% simulated muddy interlayers.

Images