Ore prospecting method for brine type lithium-potassium-boron ore deposit in structural transition area of broken basin

Abstract

The invention provides a prospecting method for a brine type lithium-potassium-boron ore deposit in a structure transition area of a broken basin. The method comprises the steps that the type of a prospecting target layer is determined; the method comprises the following steps: acquiring gravity and magnetic data and seismic data of a broken basin, identifying a fault and / or identifying a deep and large fracture and / or identifying a volcanic rock mass, and determining a primary favorable metallogenic structure unit; for the first-stage favorable metallogenic structure unit, analyzing differential settlement of adjacent structure units, and determining a second-stage favorable metallogenic structure unit; determining a first-stage favorable exploration area for the second-stage favorable metallogenic structure unit, and further determining a second-stage favorable exploration area; drilling verification is carried out on the determined secondary favorable exploration area, and the physical property parameters of the brine type lithium potassium boron ore deposit are detected. The method can rapidly and accurately delineate the brine type lithium-potassium-boron ore deposit in the fault basin, and is especially suitable for rapid positioning and evaluation of the brine type lithium-potassium-boron resources in the continental fault basin.

Description

Technical Field

[0001] The present application relates to the technical field of geological exploration of lithium potassium boron deposits, and in particular to a method for prospecting brine-type lithium potassium boron deposits in a fault basin structural conversion zone. Background Art

[0002] With the rapid development of the global new energy and new materials industries, demand for strategic mineral resources such as potassium (K), lithium (Li), and boron (B) has skyrocketed. Lithium, as a core raw material for power batteries, has become a key resource for energy transition; potash salts are an important source of agricultural fertilizer; and boron is widely used in high-temperature alloys, glass, and ceramics. In recent years, brine deposits have become a key source of potassium, lithium, and boron resources due to their large reserves and low mining costs. This is particularly true in closed basins in arid and semi-arid regions, where brine deposits are often closely associated with salt lakes or deep underground brine systems.

[0003] As a typical active tectonic unit, the fault basin often develops multiple stages and types of tectonic transition zones (such as fault zones, slope zones, depression-uplift transition zones, etc.) within it. These tectonic transition zones often become favorable areas for brine enrichment and mineralization due to changes in the tectonic stress field, complex fluid migration channels and differentiated sedimentary environments. At present, existing technologies at home and abroad mostly focus on the exploration of shallow salt lake brine or a single tectonic unit, while the research on brine-type multi-element co-existing deposits in deep tectonic transition zones is relatively weak, especially for the "structure controls the basin, the basin controls the brine, and the brine controls the mineralization" law unique to the fault basin. A complete set of prospecting technology systems has not yet been formed. Therefore, it is urgent to develop an efficient prospecting method for brine-type lithium potassium boron deposits in the tectonic transition zone of the fault basin. Through the integration and innovation of multidisciplinary technologies, the technical bottleneck of resource exploration under complex geological background can be solved, and scientific support can be provided for the increase of strategic mineral resources. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present application provides a method for prospecting brine-type lithium potassium boron deposits in a tectonic conversion zone of a fault basin, the method comprising:

[0005] Using the global paleoclimate database, we screened drought events experienced during the formation and evolution of the fault basin and identified potential target layers for mineral exploration.

[0006] For the potential prospecting target layer, the type of the prospecting target layer is determined based on the thickness of the evaporite minerals in the prospecting target layer and the proportion of potassium and magnesium salt minerals in the evaporite minerals in the prospecting target layer;

[0007] Obtaining gravity and magnetic data and seismic data of the fault basin, processing and geologically interpreting the gravity and magnetic data and seismic data to obtain interpreted gravity and magnetic data and interpreted seismic data; identifying faults based on the interpreted gravity and magnetic data and interpreted seismic data, determining a first-level favorable metallogenic tectonic unit and / or identifying deep and large faults, determining a first-level favorable metallogenic tectonic unit and / or identifying volcanic rock bodies, determining a first-level favorable metallogenic tectonic unit; the first-level favorable metallogenic tectonic unit includes a dominant favorable metallogenic tectonic unit, a well-favored metallogenic tectonic unit, and a generally favorable metallogenic tectonic unit;

[0008] For the first-level favorable metallogenic structural unit, analyzing the differential settlement of adjacent structural units to determine the second-level favorable metallogenic structural unit;

[0009] For the secondary favorable metallogenic structural units, low-lying areas are identified using seismic data, gravity and magnetic data, drilling data, and outcrop data. The primary favorable exploration areas are determined by combining the fault structures of the fault basin and the distribution range of volcanic rock bodies.

[0010] For the first-level favorable exploration area, identify fluvial facies, delta facies and sedimentary microfacies to determine the second-level favorable exploration area;

[0011] Drilling verification is carried out for the determined secondary favorable exploration areas, and the ICP-MS method is used to analyze the K, Li, and B contents and detect the physical properties of brine-type lithium potassium boron deposits.

[0012] Furthermore, the identification of faults and determination of primary favorable metallogenic structural units include:

[0013] Determine the fault type and fault activity intensity of the structural transformation zone of the fault basin based on the gravity and magnetic data of the fault basin;

[0014] Based on the seismic data of the fault basin, the fault types and fault activity intensity of the tectonic transition zone of the fault basin determined based on gravity and magnetic data are compared, and the fault types, development characteristics and tectonic activity periods of the prospecting target layer and its surrounding layers are analyzed;

[0015] The first-level favorable mineralization structural unit is determined based on the fault type, development characteristics and tectonic activity period of the prospecting target layer and its surrounding layers.

[0016] Furthermore, the determination of the first-level favorable metallogenic structural unit based on the fault type, development characteristics and tectonic activity period of the prospecting target layer and its surrounding layers includes:

[0017] Determine the activity intensity of normal faults and detachment faults after the formation of the prospecting target layer. If the activity intensity is strong or medium, classify the structural unit where the normal faults and detachment faults are located as a dominant and favorable metallogenic structural unit.

[0018] Determine the activity intensity of the reverse fault after the formation of the prospecting target layer. If the activity intensity is weak, classify the structural unit where the reverse fault is located as a dominant and favorable metallogenic structural unit.

[0019] Determine the time when the strike-slip fault and reversal fault undergo tectonic reversal and tectonic strike-slip. If it occurs after the formation of the prospecting target layer, the tectonic unit where the strike-slip fault and reversal fault are located is divided into a dominant and favorable mineralization tectonic unit.

[0020] Furthermore, the identification of faults and determination of favorable metallogenic structural units include:

[0021] For the structural unit where the fault is located, determine the burial depth of the prospecting target layer and calculate the normal temperature of the prospecting target layer based on the annual average surface temperature;

[0022] Collect geophysical logging data of the structural unit where the fault is located to determine the well temperature of the target layer for prospecting;

[0023] If the well temperature of the prospecting target layer is greater than 140% of the normal temperature, the structural unit where the fault is located will be divided into a dominant and favorable mineralization structural unit;

[0024] If the well temperature of the prospecting target layer is greater than 120% of the normal temperature and less than or equal to 140% of the normal temperature, the structural unit where the fault is located is divided into a favorable mineralization structural unit;

[0025] If the well temperature of the prospecting target layer is less than or equal to 120% of the normal temperature, the structural unit where the fault is located will be divided into a generally favorable mineralization structural unit.

[0026] Furthermore, the identification of deep and large faults and determination of the first-level favorable metallogenic structural units include:

[0027] The spatial distribution and activity of deep faults can be identified through the coordinated analysis of Bouguer gravity anomaly gradient zones and aeromagnetic vertical second-order derivative anomalies.

[0028] The coherence volume and curvature attributes of seismic data are used to further refine the fault geometry, quantitatively characterize the activity intensity based on the sudden change of the cross-section dip angle and the thickness ratio of the growth layer, and analyze the development characteristics of deep and large faults after the formation of the prospecting target layer;

[0029] If after the formation of the prospecting target layer, the deep fault appears as a normal fault or a detachment fault, then the structural unit where the deep fault is located is divided into a dominant and favorable metallogenic structural unit;

[0030] If after the formation of the prospecting target layer, the deep and large fault appears as a strike-slip fault or an inversion fault, then the structural unit where the deep and large fault is located will be divided into a favorable mineralization structural unit.

[0031] Furthermore, the identification of volcanic rock bodies and determination of primary favorable metallogenic structural units include:

[0032] Through combined analysis of gravity and magnetic anomalies and vertical derivative processing to enhance boundary identification, the spatial morphology of rock masses can be determined, and volcanic rocks can be distinguished from sedimentary rocks or intrusive rocks.

[0033] If there is a volcanic rock body in a tectonic unit and its distribution range is greater than or equal to 1 / 5 of the area of ​​the tectonic unit, the tectonic unit is classified as a dominant and favorable metallogenic tectonic unit;

[0034] If there is a volcanic rock body in a tectonic unit and its distribution range is greater than or equal to 1 / 10 and less than 1 / 5 of the area of ​​the tectonic unit, the tectonic unit is classified as a favorable mineralization tectonic unit;

[0035] If there is a volcanic rock body in a tectonic unit and its distribution range is less than 1 / 10 of the area of ​​the tectonic unit, the tectonic unit will be classified as a generally favorable mineralization tectonic unit.

[0036] Furthermore, for the first-level favorable metallogenic structural unit, analyzing the differential settlement of adjacent structural units to determine the second-level favorable metallogenic structural unit includes:

[0037] For a dominant and favorable metallogenic structural unit, if there is a subsidence difference between adjacent structural units in one stratum below the prospecting target layer, and this relative subsidence difference continues after the formation of the subsidence difference, the footwall is classified as a Class A dominant and favorable metallogenic structural unit;

[0038] For a dominant and favorable metallogenic structural unit, if there is no settlement difference between adjacent structural units in one stratum below the prospecting target layer, but there is a settlement difference when the prospecting target layer is formed, and this relative settlement difference has continued since then, the footwall is classified as a Class B dominant and favorable metallogenic structural unit;

[0039] For favorable metallogenic structural units, if there is a difference in settlement between adjacent structural units in one stratum below the prospecting target layer, but this differential settlement ends after the formation of the prospecting target layer, the footwall is classified as a Class A favorable metallogenic structural unit.

[0040] For favorable metallogenic structural units, if there is no settlement difference between adjacent structural units in one stratum below the prospecting target layer, but there is a settlement difference when the prospecting target layer is formed, and this settlement difference ends after the prospecting target layer is formed, then the footwall is classified as a Class B favorable metallogenic structural unit;

[0041] For generally favorable metallogenic structural units, if there is no difference in settlement between adjacent structural units and the stratum below the prospecting target layer, but there is differential settlement after the formation of the prospecting target layer, and this relative settlement difference continues thereafter, then the footwall is classified as a type A generally favorable metallogenic structural unit;

[0042] For generally favorable metallogenic structural units, if there is no settlement difference between the adjacent structural units and the stratum below the prospecting target layer, but there is differential settlement after the formation of the prospecting target layer, but the settlement difference ends thereafter, then the footwall is determined to be a Class B generally favorable metallogenic structural unit.

[0043] Furthermore, for the secondary favorable metallogenic structural unit, the low-lying areas are determined using seismic data, gravity and magnetic data, drilling data and outcrop data, and the primary favorable exploration areas are determined in combination with the fault structure and volcanic rock distribution range of the fault basin, including:

[0044] The faults, basement interfaces and sedimentary layer thickness were identified through seismic reflection profile interpretation, and the basement depression area was preliminarily delineated.

[0045] Process gravity and magnetic data, extract low gravity anomalies and magnetic flat areas, and compare and verify them with seismic basement depth;

[0046] Seismic interpretation results are used to constrain gravity-magnetic joint inversion and fit measured data to accurately depict the spatial morphology of low-lying areas.

[0047] Combined with the calibration of borehole data and outcrop data, low-lying areas are comprehensively identified;

[0048] Compare the spatial relationships between topographic depressions and normal faults and volcanic rock bodies within the same favorable metallogenic tectonic unit;

[0049] If the low-lying area is located around normal faults and volcanic rock bodies, the low-lying area is determined to be a favorable exploration area;

[0050] If the low-lying area is located around a normal fault or volcanic rock mass, the low-lying area is determined to be a good and favorable exploration area;

[0051] If the low-lying area is within 50 km from the normal fault or volcanic rock body, it is determined to be a generally favorable exploration area.

[0052] Furthermore, for the first-level favorable exploration area, the fluvial facies, delta facies and sedimentary microfacies are identified to determine the second-level favorable exploration area, including:

[0053] Through well-seismic calibration, the sand bodies interpreted by logging are matched with seismic facies, and the fluvial and deltaic facies are identified by combining seismic attributes and regional sedimentary background.

[0054] Identify deltaic sedimentary microfacies according to the identification marks of deltaic sedimentary microfacies;

[0055] Identify fluvial sedimentary microfacies based on fluvial sedimentary microfacies identification marks;

[0056] Based on grain size, single sand body thickness, and sand-to-ground ratio, the order of merit of brine reservoir sand bodies in deltaic sedimentary systems and fluvial sedimentary systems was determined. The order of merit of brine reservoir sand bodies in deltaic sedimentary systems is: distributary channel microfacies, estuary bar microfacies, underwater distributary channel microfacies, breach fan microfacies, and sheet sand microfacies; the order of merit of brine reservoir sand bodies in fluvial sedimentary systems is: channel fill, mid-shoal, side-shoal, abandoned channel, and natural levee.

[0057] According to the order of merit of the brine reservoir sand bodies in the deltaic sedimentary system and the order of merit of the brine reservoir sand bodies in the fluvial sedimentary system, the secondary favorable exploration areas are determined.

[0058] Furthermore, the order of merit of the brine reservoir sand bodies in the deltaic sedimentary system and the order of merit of the brine reservoir sand bodies in the fluvial sedimentary system determine the secondary favorable exploration areas, including:

[0059] For deltaic sedimentary systems, the method for determining secondary favorable exploration areas is as follows:

[0060] If distributary channel microfacies develops in the advantageous exploration area, the advantageous exploration area will be determined as a Class A advantageous exploration area;

[0061] If the advantageous exploration area has developed estuary bar microfacies and underwater distributary channel microfacies, the advantageous exploration area will be determined as a Class B advantageous exploration area;

[0062] If the advantageous exploration area has crevasse fan microfacies and sheet sand microfacies, the advantageous exploration area will be determined as a Class C advantageous exploration area;

[0063] If distributary channel microfacies develops in the favorable exploration area, the favorable exploration area will be determined as a Class A favorable exploration area;

[0064] If the favorable exploration area has developed estuary bar microfacies and underwater distributary channel microfacies, the favorable exploration area will be determined as Class B favorable exploration area;

[0065] If the favorable exploration area has crevasse fan microfacies and sheet sand microfacies, the favorable exploration area will be determined as a Class C favorable exploration area;

[0066] If distributary channel microfacies develops in a generally favorable exploration area, the generally favorable exploration area will be determined as a Class A generally favorable exploration area;

[0067] If the generally favorable exploration area develops estuary bar microfacies and underwater distributary channel microfacies, the generally favorable exploration area will be determined as a Class B generally favorable exploration area;

[0068] If the generally favorable exploration area has crevasse fan microfacies and sheet sand microfacies, the generally favorable exploration area will be determined as a Class C generally favorable exploration area;

[0069] For fluvial sedimentary systems, the method for determining secondary favorable exploration areas is as follows:

[0070] If the advantageous exploration area develops channel filling microfacies, the advantageous exploration area will be determined as a Class A advantageous exploration area;

[0071] If the advantageous exploration area has core and side shoals, it will be classified as a Class B advantageous exploration area;

[0072] If abandoned river channels and natural levees are developed in the advantageous exploration area, the advantageous exploration area will be determined as a Class C advantageous exploration area;

[0073] If the channel filling microfacies is developed in the favorable exploration area, the favorable exploration area will be determined as a Class A favorable exploration area;

[0074] If a favorable exploration area has core and side shoals, it will be classified as a Class B favorable exploration area.

[0075] If abandoned river channels and natural levees are developed in the favorable exploration area, the favorable exploration area will be determined as a Class C favorable exploration area;

[0076] If the generally favorable exploration area develops channel filling microfacies, the generally favorable exploration area will be determined as a Class A generally favorable exploration area;

[0077] If a generally favorable exploration area has core and side shoals, it will be classified as a Class B generally favorable exploration area;

[0078] If abandoned river channels and natural levees develop in a generally favorable exploration area, the generally favorable exploration area will be determined as a Class C generally favorable exploration area.

[0079] Based on the above invention content, compared with the existing technology, this application starts from the actual prospecting needs and mineralization characteristics of brine-type lithium potassium boron deposits, focuses on the key area of ​​the tectonic conversion zone of the fault basin, and innovatively proposes a multi-factor coupled structural control model. Combined with the global paleoclimate database to accurately screen drought events, rapid identification of target layers for prospecting of lithium potassium boron-rich brine in paleoclimate-tectonic coordination is achieved; through the fusion of gravity and magnetic data with seismic data, key elements such as faults, fractures, volcanic bodies and differential subsidence are integrated to dynamically select favorable mineralization structural units; based on seismic data, structural low-lying areas and sedimentary phase characteristics are characterized to determine favorable exploration areas. Finally, through drilling verification and ICP-MS high-efficiency detection technology, it is determined whether lithium potassium boron meets the requirements for industrial utilization. Form an integrated evaluation system of "determination of prospecting target layers-optimization of favorable mineralization structural units-optimization of favorable exploration areas-drilling + geochemical verification", which significantly improves the exploration efficiency of brine-type lithium potassium boron resources in continental fault basins. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0081] Figure 1 It is a flow chart of a prospecting method for brine-type lithium-potassium-boron deposits in a tectonic conversion zone of a fault basin provided in an embodiment of the present application. DETAILED DESCRIPTION

[0082] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0083] It should be understood that the embodiments described are only a portion of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0084] See also Figure 1 , is a flow chart of a prospecting method for brine-type lithium potassium boron deposits in a fault basin structural conversion zone provided by an embodiment of the present invention. Figure 1 As shown, the method specifically includes:

[0085] Step S1: Using the global paleoclimate database, screen the drought events experienced during the formation and evolution stage of the fault basin to determine the potential prospecting target layer.

[0086] Collect global paleoclimate databases (such as Pangaea, NOAAPaleoclimatology), screen drought events experienced during the formation and evolution stage of the fault basin, and identify sedimentary strata formed during the drought event and their adjacent strata as potential prospecting target layers.

[0087] Step S2: For the potential prospecting target layer, the type of the prospecting target layer is determined according to the thickness of the evaporite minerals in the prospecting target layer and the proportion of potassium and magnesium salt minerals in the evaporite minerals in the prospecting target layer.

[0088] During salt lake brine mineralization, evaporite minerals include sulfates, borates, halites, and potassium-magnesium salts. The order of evaporite mineral formation is primarily controlled by the degree of evaporation concentration and mineral solubility. According to a typical evaporite sedimentary sequence, the order of evaporite mineral formation is generally: sulfates, borates, halites, and potassium-magnesium salts.

[0089] Drilling data from the fault basin is collected, focusing on potential prospecting target layers to determine whether the aforementioned evaporite minerals are present in these layers. If present, the type of the target layer is determined based on the thickness of the evaporite minerals. If the evaporite mineral thickness is greater than or equal to 1 / 4 of the thickness of the underlying layer, the potential target layer is considered a high-quality target layer. If the evaporite mineral thickness is greater than or equal to 1 / 8 of the underlying layer thickness and less than 1 / 4 of the underlying layer thickness, the potential target layer is considered a good target layer. If the evaporite mineral thickness is less than 1 / 8 of the underlying layer thickness, the potential target layer is considered a general target layer.

[0090] According to the proportion of potassium and magnesium salt minerals in the evaporite minerals of the prospecting target layer, the type of the prospecting target layer is further determined.

[0091] If the proportion of potassium-magnesium salt minerals in the evaporite minerals of the high-quality prospecting target layer is greater than or equal to 1 / 6, the high-quality prospecting target layer is determined to be a Class A high-quality prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the high-quality prospecting target layer is greater than or equal to 1 / 10 and less than 1 / 6, and the proportion of borate minerals and halite minerals is greater than or equal to 1 / 6, the high-quality prospecting target layer is determined to be a Class B high-quality prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the high-quality prospecting target layer is less than 1 / 10, and the proportion of borate minerals and halite minerals is greater than or equal to 1 / 6, the high-quality prospecting target layer is determined to be a Class C high-quality prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the high-quality prospecting target layer is less than 1 / 10, and the proportion of borate minerals and halite minerals is less than 1 / 6, the high-quality prospecting target layer is determined to be a Class D high-quality prospecting target layer.

[0092] If the proportion of potassium-magnesium salt minerals in the evaporite minerals of the good prospecting target layer is greater than or equal to 1 / 6, the good prospecting target layer is determined to be a Class A good prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the good prospecting target layer is greater than or equal to 1 / 10 and less than 1 / 6, and the proportion of borate minerals and halite minerals is greater than or equal to 1 / 6, the good prospecting target layer is determined to be a Class B good prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the good prospecting target layer is less than 1 / 10, and the proportion of borate minerals and halite minerals is greater than or equal to 1 / 6, the good prospecting target layer is determined to be a Class C good prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the good prospecting target layer is less than 1 / 10, and the proportion of borate minerals and halite minerals is less than 1 / 6, the good prospecting target layer is determined to be a Class D good prospecting target layer.

[0093] If the proportion of potassium-magnesium salt minerals in the evaporite minerals of the general prospecting target layer is greater than or equal to 1 / 6, the general prospecting target layer shall be determined as a Class A general prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the general prospecting target layer is greater than or equal to 1 / 10 and less than 1 / 6, and the proportion of borate minerals and halite minerals is greater than or equal to 1 / 6, the general prospecting target layer shall be determined as a Class B general prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the general prospecting target layer is less than 1 / 10, and the proportion of borate minerals and halite minerals is greater than or equal to 1 / 6, the general prospecting target layer shall be determined as a Class C general prospecting target layer; if the proportion of potassium-magnesium salt minerals in the evaporite minerals of the general prospecting target layer is less than 1 / 10, and the proportion of borate minerals and halite minerals is less than 1 / 6, the general prospecting target layer shall be determined as a Class D general prospecting target layer.

[0094] Prospecting analysis is carried out in the area where the prospecting target layer is located in the order of high-quality prospecting target layer, good prospecting target layer and general prospecting target layer.

[0095] Step S3: acquiring gravity and magnetic data and seismic data of the fault basin, processing and geologically interpreting the gravity and magnetic data and seismic data to obtain interpreted gravity and magnetic data and interpreted seismic data;

[0096] According to the interpreted gravity and magnetic data and the interpreted seismic data, faults are identified to determine the primary favorable mineralization structural unit and / or deep and large faults are identified to determine the primary favorable mineralization structural unit and / or volcanic rock bodies are identified to determine the primary favorable mineralization structural unit; the primary favorable mineralization structural unit includes a dominant favorable mineralization structural unit, a well favorable mineralization structural unit and a generally favorable mineralization structural unit.

[0097] The processing of gravity and magnetic data includes:

[0098] (1) Bouguer gravity anomaly data processing process:

[0099] a. Convert the public XYZ gravity data into a grid file; b. Calculate the free air anomaly; c. Perform Bouguer correction; d. Perform terrain correction; e. Verify the accuracy. The density of the fault basin is 2.3-2.5 g / cm 3 When performing terrain correction, the data area should be expanded by at least 50 km to avoid boundary errors. The error should be checked by comparing with known absolute gravity points (such as BGI benchmarks) to ensure that the error should be <1 mGal.

[0100] The spatial derivatives are calculated using the horizontal gradient (THG) and vertical gradient (VG) algorithms, and significant gradient bands are extracted through threshold segmentation or edge enhancement techniques to obtain the Bouguer gravity anomaly map.

[0101] (2) Aeromagnetic vertical second-order derivative processing flow:

[0102] a. Data preprocessing, specifically gridding the data using the Kriging interpolation method, with the grid spacing set to 1 / 3 of the flight altitude; b. Frequency domain conversion calculations, including applying a fast Fourier transform to the gridded data; c. Optimizing the calculation results, using regularized inversion to suppress noise amplification; performing upward extension verification, with the extension altitude ≥ 3 times the grid spacing; and using a sliding average filter to smooth high-frequency oscillations.

[0103] The identification of faults and determination of the first-level favorable metallogenic structural units include:

[0104] First, based on the gravity and magnetic data of the fault basin, the fault type and fault activity intensity in the structural transformation zone of the fault basin are determined.

[0105] Fault basins usually have normal faults, detachment faults, inversion faults, strike-slip faults, and reverse faults. The fault type is determined based on the response of the fault on the gravity and magnetic data profile, including:

[0106] If the Bouguer gravity anomaly gradient zone corresponding to the fault presents a linear high value, the zero value line of the magnetic vertical derivative coincides with the gravity gradient axis, and the magnetic anomaly vertical derivative shows a single-sided steep change with the same dip, then the fault is judged to be a normal fault;

[0107] If the gravity gradient zone corresponding to the fault is distributed in an arc shape, the magnetic vertical derivative shows a "double zero value line", and the magnetic permeability value drops sharply on the hanging wall of the fault, then the fault is judged to be a detachment fault;

[0108] If the Bouguer gravity anomaly corresponding to the fault is a linear gradient zone and the magnetic anomaly is a high-intensity linear strip or fault, the fault is determined to be a strike-slip fault;

[0109] If the Bouguer gravity anomaly corresponding to the fault is low in the early stage and high in the later stage, and the magnetic anomaly base is uplifted to cause complexity, then the fault is determined to be a reversal fault;

[0110] If the Bouguer gravity anomaly corresponding to the fault has a higher value on the hanging wall and a lower value on the footwall, and the magnetic anomaly has a higher magnetic force on the hanging wall and a magnetic quiet state at the front edge, then the fault is determined to be a reverse fault;

[0111] The extensional characteristics of the normal fault, detachment fault, strike-slip fault, inversion fault, and reverse fault decrease in order. The stronger the extensional characteristics of the fault, the more favorable for the formation of brine-type lithium, potassium, and boron deposits.

[0112] After interpreting the fault type based on the gravity and magnetic data profiles, calculate the gravity gradient slope Kg or calculate the magnetic activity index MAI, and judge the fault activity intensity based on the gravity gradient slope Kg or the magnetic activity index MAI;

[0113] The judgment of the fault activity intensity based on the gravity gradient slope Kg includes:

[0114] If Kg > 20, it is determined that the fault activity is strong;

[0115] If 10 < Kg ≤ 20, it is determined that the fault activity is medium;

[0116] If Kg ≤ 10, it is determined that the fault activity is weak;

[0117] The judgment of the fault activity intensity based on the magnetic activity index MAI includes:

[0118] If MAI > 80 nT / m 2 / km, it is determined that the fault activity is strong;

[0119] If 30 nT / m 2 / km < MAI ≤ 80 nT / m 2 / km, it is determined that the fault activity is medium;

[0120] If MAI ≤ 30 nT / m 2 / km, it is determined that the fault activity is weak.

[0121] Secondly, based on the seismic data of the fault depression basin, compare the fault type and fault activity intensity of the tectonic transformation zone of the fault depression basin determined from the gravity and magnetic data, and analyze the fault type, development characteristics, and tectonic activity periods of the ore prospecting target layer and its surrounding horizons.

[0122] Under the constraint of borehole data, trace each reflection interface of the seismic profile to determine the spatial distribution of the strata, especially the ore prospecting target layer.

[0123] Seismic attributes such as coherence volumes, curvature, and spectral decomposition are used to identify synsedimentary faults, growth strata, and onlap / onlap interfaces, thereby delineating periods of tectonic activity (e.g., rifting and depression). The analysis focuses on analyzing the fault properties, development characteristics, and activity periods of the target strata and surrounding horizons. Faults that were active after the formation of the target strata, those that were active early in the past, and those that were reactivated later in the future are identified. These faults are then compared with faults interpreted from gravity and magnetic profiles to further characterize their development within the target strata.

[0124] Finally, the first-level favorable mineralization structural unit is determined based on the fault type, development characteristics and tectonic activity period of the prospecting target layer and its surrounding layers.

[0125] Determine the activity intensity of normal faults and detachment faults after the formation of the prospecting target layer. If the activity intensity is strong or medium, classify the structural unit where the normal faults and detachment faults are located as a dominant and favorable metallogenic structural unit.

[0126] Determine the activity intensity of the reverse fault after the formation of the prospecting target layer. If the activity intensity is weak, classify the structural unit where the reverse fault is located as a dominant and favorable metallogenic structural unit.

[0127] Determine the time when the strike-slip fault and reversal fault undergo tectonic reversal and tectonic strike-slip. If it occurs after the formation of the prospecting target layer, the tectonic unit where the strike-slip fault and reversal fault are located is divided into a dominant and favorable mineralization tectonic unit.

[0128] In one embodiment, the identifying of faults and determining a primary favorable metallogenic structural unit may include:

[0129] For the tectonic unit where the fault is located, determine the burial depth of the target layer for prospecting, and calculate the normal temperature of the target layer for prospecting based on the annual average surface temperature.

[0130] Among them, the geothermal gradient of the fault basin is generally 30-35℃ / km, and the geothermal gradient of the fault basin in this application is 33℃ / km.

[0131] The calculation formula for the normal temperature of the prospecting target layer is:

[0132] T z =z*G+T0

[0133] Among them, T z is the temperature at depth z; T0 is the annual average surface temperature; z is the depth; G is the geothermal gradient of the fault basin.

[0134] The normal temperature of the target layer for prospecting can be calculated by the above formula.

[0135] Collect geophysical logging data of the structural unit where the fault is located, analyze the well temperature data, and determine the well temperature of the target layer for prospecting.

[0136] If the well temperature of the prospecting target layer is greater than 140% of the normal temperature, the structural unit where the fault is located will be divided into a dominant and favorable mineralization structural unit;

[0137] If the well temperature of the prospecting target layer is greater than 120% of the normal temperature and less than or equal to 140% of the normal temperature, the structural unit where the fault is located is divided into a favorable mineralization structural unit;

[0138] If the well temperature of the prospecting target layer is less than or equal to 120% of the normal temperature, the structural unit where the fault is located will be divided into a generally favorable mineralization structural unit.

[0139] In one embodiment, by identifying deep and large faults, a favorable first-level metallogenic structural unit is determined, specifically including:

[0140] The spatial distribution and activity of deep faults are identified through a collaborative analysis of Bouguer gravity anomaly gradient zones and aeromagnetic vertical second-order derivative anomalies. Linear anomaly zones in the horizontal gravity gradient reflect density abrupt changes, while the zero-value lines of the vertical derivative of the magnetic anomaly indicate the location of magnetic basement breakage. The spatial coupling between these two zones corresponds to the location of deep faults. The presence of deep faults facilitates the transport of deep magma and hydrothermal fluids to shallow depths, favoring uranium mineralization; the opposite is unfavorable.

[0141] The coherence volume and curvature attributes of seismic data are used to further refine the fault geometry, quantitatively characterize the activity intensity based on the sudden change of the section dip angle and the thickness ratio of the growth stratum, and analyze the development characteristics of deep and large faults after the formation of the prospecting target layer.

[0142] If after the formation of the prospecting target layer, the deep fault appears as a normal fault or a detachment fault, then the structural unit where the deep fault is located is divided into a dominant and favorable metallogenic structural unit;

[0143] If after the formation of the prospecting target layer, the deep and large fault appears as a strike-slip fault or an inversion fault, then the structural unit where the deep and large fault is located will be divided into a favorable mineralization structural unit.

[0144] In one embodiment, the first-level favorable metallogenic structural unit is determined by identifying the volcanic rock body, which specifically includes:

[0145] Through combined analysis of gravity and magnetic anomalies and vertical derivative processing, boundary identification is enhanced, the spatial morphology of the rock mass is determined, and volcanic rocks are distinguished from sedimentary rocks or intrusive rocks.

[0146] The use of gravity and magnetic data to identify volcanic rock bodies is mainly based on the density and magnetic differences between them and the surrounding rocks: basic volcanic rocks (such as basalt) have high density (2.8-3.0 g / cm 3) and are rich in magnetic minerals, often manifesting as localized high gravity and drastically changing high magnetic anomalies. These anomalies often appear as isolated masses or bands with steep boundary gradients. Intermediate-acidic volcanic rocks (such as rhyolite) have low density and weak magnetism, resulting in less pronounced gravity anomalies and smaller magnetic anomaly amplitudes. By combining gravity and magnetic anomaly analysis (e.g., high gravity and high magnetism indicate basic rock masses) and using vertical derivative processing to enhance boundary identification and determine the spatial morphology of rock masses, volcanic rocks can be effectively distinguished from sedimentary or intrusive rocks.

[0147] If there is a volcanic rock body in a tectonic unit and its distribution range is greater than or equal to 1 / 5 of the area of ​​the tectonic unit, the tectonic unit is classified as a dominant and favorable metallogenic tectonic unit;

[0148] If there is a volcanic rock body in a tectonic unit and its distribution range is greater than or equal to 1 / 10 and less than 1 / 5 of the area of ​​the tectonic unit, the tectonic unit is classified as a favorable mineralization tectonic unit;

[0149] If there is a volcanic rock body in a tectonic unit and its distribution range is less than 1 / 10 of the area of ​​the tectonic unit, the tectonic unit will be classified as a generally favorable mineralization tectonic unit.

[0150] Step S4: For the first-level favorable metallogenic structural unit, analyze the differential settlement of adjacent structural units to determine the second-level favorable metallogenic structural unit.

[0151] Seismic data is used to calculate tectonic subsidence for the stratum immediately below and overlying the target stratum. The higher-lying tectonic unit among adjacent tectonic units is designated as the hanging wall, while the lower-lying tectonic unit is designated as the foot wall. Stratigraphic dip is measured using the reflection event dips of the target stratum from seismic data. Seismic geology data is used to obtain the inter-stratum velocity of the target stratum, and differential subsidence is calculated using the following formula. The greater the differential subsidence, the more favorable the mineralization potential.

[0152]

[0153] Among them, v 层 is the layer velocity of the prospecting target layer; θ is the formation dip angle of the prospecting target layer; t 下盘 is the two-way travel time of the footwall earthquake, t 上盘 It is the two-way travel time of the upper plate earthquake.

[0154] For a dominant and favorable metallogenic structural unit, if there is a subsidence difference between adjacent structural units in one stratum below the prospecting target layer, and this relative subsidence difference continues after the formation of the subsidence difference, the footwall is classified as a Class A dominant and favorable metallogenic structural unit;

[0155] For a dominant and favorable metallogenic structural unit, if there is no settlement difference between adjacent structural units in one stratum below the prospecting target layer, but there is a settlement difference when the prospecting target layer is formed, and this relative settlement difference has continued since then, the footwall is classified as a Class B dominant and favorable metallogenic structural unit;

[0156] For favorable metallogenic structural units, if there is a difference in settlement between adjacent structural units in one stratum below the prospecting target layer, but this differential settlement ends after the formation of the prospecting target layer, the footwall is classified as a Class A favorable metallogenic structural unit.

[0157] For favorable metallogenic structural units, if there is no settlement difference between adjacent structural units in one stratum below the prospecting target layer, but there is a settlement difference when the prospecting target layer is formed, and this settlement difference ends after the prospecting target layer is formed, then the footwall is classified as a Class B favorable metallogenic structural unit;

[0158] For generally favorable metallogenic structural units, if there is no difference in settlement between adjacent structural units and the stratum below the prospecting target layer, but there is differential settlement after the formation of the prospecting target layer, and this relative settlement difference continues thereafter, then the footwall is classified as a type A generally favorable metallogenic structural unit;

[0159] For generally favorable metallogenic structural units, if there is no settlement difference between the adjacent structural units and the stratum below the prospecting target layer, but there is differential settlement after the formation of the prospecting target layer, but the settlement difference ends thereafter, then the footwall is determined to be a Class B generally favorable metallogenic structural unit.

[0160] Step S5: For the secondary favorable metallogenic structural unit, the low-lying areas are determined using seismic data, gravity and magnetic data, drilling data and outcrop data, and the primary favorable exploration areas are determined in combination with the fault structure of the fault basin and the distribution range of the volcanic rock mass.

[0161] The first-level favorable exploration areas include dominant favorable exploration areas, good favorable exploration areas and generally favorable exploration areas.

[0162] Seismic data and gravity and magnetic data are used to collaboratively identify low-lying areas in fault basins. Through multi-data fusion and cross-validation, the structural framework, basement morphology, and sedimentary filling characteristics of the basins are revealed. The specific steps are as follows:

[0163] The faults, basement interfaces and sedimentary layer thickness were identified through seismic reflection profile interpretation, and the basement depression area was preliminarily delineated.

[0164] Process gravity and magnetic data, extract low gravity anomalies and magnetic flat areas, and compare and verify them with seismic basement depth;

[0165] Seismic interpretation results are used to constrain gravity-magnetic joint inversion and fit measured data to accurately depict the spatial morphology of low-lying areas.

[0166] The low-lying areas were comprehensively identified by combining the calibration of borehole data and outcrop data.

[0167] Compare the spatial relationships between topographic depressions and normal faults and volcanic rock bodies within the same favorable metallogenic tectonic unit;

[0168] If the low-lying area is located around normal faults and volcanic rock bodies, the low-lying area is determined to be a favorable exploration area;

[0169] If the low-lying area is located around a normal fault or volcanic rock mass, the low-lying area is determined to be a good and favorable exploration area;

[0170] If the low-lying area is within 50 km from the normal fault or volcanic rock body, it is determined to be a generally favorable exploration area.

[0171] Step S6: For the first-level favorable exploration area, identify the fluvial facies, delta facies and sedimentary microfacies to determine the second-level favorable exploration area.

[0172] Fault basins are mostly continental, typically developing fluvial, deltaic, lacustrine, swampy, and fan-deltaic sedimentary types. Fluvial and deltaic sediments often contain well-connected sand bodies, providing migration pathways and storage space for brine accumulation. Therefore, identifying fluvial and deltaic sediments with favorable mineralization structures is a key priority for selecting favorable exploration areas.

[0173] Sedimentary facies and microfacies are primarily identified using seismic and well-logging data. These microfacies can be effectively identified by integrating well-logging morphological analysis with seismic multi-attribute interpretation (coherence volume, curvature, and spectral decomposition). Well-logging data provides precise calibration of vertical lithologic variations, while seismic data provides a macroscopic depiction of the planar distribution of microfacies. This combination overcomes the limitations of single data sets.

[0174] Fluvial facies exhibit lens-like or filling-like reflections on seismic data, with a zonal distribution in the horizontal plane. Well logs show bell-shaped or box-shaped gamma ray patterns, reflecting the positive rhythmic characteristics of channel sand bodies. Deltaic facies, on the other hand, have distinct progradational reflection structures (e.g., S-shaped or oblique reflections) and a lobate distribution in the horizontal plane. Well logs typically feature funnel-shaped gamma ray patterns, indicating antirhythmic mouth-bar deposits. Well-seismic calibration, matching the sand bodies interpreted from well logs with seismic facies and combining seismic attributes (e.g., coherence volume, root mean square amplitude) with the regional sedimentary context, effectively distinguishes these two sedimentary facies.

[0175] After identifying the fluvial facies and delta facies, the delta facies sedimentary microfacies are identified based on the delta facies sedimentary microfacies identification marks; the fluvial facies sedimentary microfacies are identified based on the fluvial facies sedimentary microfacies identification marks.

[0176] The deltaic sedimentary microfacies identification marks include:

[0177] Distributary channel microfacies: It appears as narrow strip-shaped strong amplitude reflection on seismic observation, lens-shaped cross section, and dendritic branching characteristics on plane coherence slices. The well logging curve responds with a box-shaped or bell-shaped GR curve as a typical response, reflecting the deposition of positive rhythmic sand bodies. Its formation is controlled by the terrain slope and sediment supply. It often coexists with natural levees, and trough-shaped cross-bedding can be seen in the core.

[0178] Mouth-bar microfacies: It has a typical progradational reflection structure (S-shaped or oblique type). The funnel-shaped GR curve of logging reveals anti-rhythmic characteristics. It is formed in the unloading area where the river enters the lake / sea and is significantly transformed by waves. Wave impedance inversion can effectively identify its sandstone and mudstone interbedded structure.

[0179] Underwater distributary channel microfacies: manifested as a low-angle downcut seismic reflection morphology with weaker amplitude than that of the onshore channel. Well logging shows a weak box-shaped GR curve with reduced resistivity. It develops in the delta front subfacies and is often accompanied by slump deformation structures.

[0180] Breach fan microfacies: It appears as a small wedge-shaped reflection on seismic observations, and plane coherence slices show a fan-shaped distribution. The toothed bell-shaped GR curve of well logging reflects the rapidly accumulated sand-mud interlayers, which were formed during the river channel breach event during the flood period.

[0181] Sheet sand microfacies: characterized by thin continuous parallel reflections, its thin interbedded structure can be identified; the low-amplitude serrated GR curve in well logging indicates low-energy environment deposition, which is common at the distal end of the delta front.

[0182] The identification marks of deltaic sedimentary microfacies are shown in Table 1.

[0183] Table 1:

[0184] Sedimentary microfacies Seismic reflection characteristics Well logging curve morphology Diversion channel Incised valley filling, box-shaped / hummock-shaped reflections Box-shaped or bell-shaped GR, sudden increase in resistivity estuary dam Precursor reflective structure, S-shaped / oblique Funnel-shaped GR, negative spontaneous potential anomaly underwater diversion channel Weak amplitude intermittent reflections, localized precession Sawtooth GR, medium to low resistivity Breach fan Messy / lenticular reflections, low continuity Low-amplitude tooth GR, resistivity fluctuation Sheet sand Parallel-subparallel reflection, high continuous Straight GR baseline, low-resistance thin layer

[0185] The fluvial sedimentary microfacies identification marks include:

[0186] Channel filling microfacies: It appears as a box-shaped or bell-shaped GR curve (positive rhythm) with a sudden change at the bottom on well logging. The resistivity curve shows a high value, corresponding to the lens-shaped strong amplitude reflection on the seismic section. The plane coherence attributes show a curved strip-like distribution.

[0187] Heart-bank microfacies: The logging response is a homogeneous box-shaped GR curve, the resistivity is stable and high, and the seismic amplitude envelope attribute shows an irregular patchy high-value area.

[0188] Beach microfacies: It has a typical bell-shaped GR logging curve (positive rhythm) and shows asymmetric lens reflection on the seismic section.

[0189] Abandoned channel microfacies: In well logging, it is manifested as a GR curve with a sudden change in the upper part (box-shaped in the lower part + low-amplitude tooth-shaped in the upper part). In seismic, it can be seen that the top of the lens is covered by continuous weak-amplitude mudstone.

[0190] Natural levee microfacies: The well logging curve shows a low-amplitude sawtooth GR response, and the seismic response is manifested as a weak-amplitude thin-layer reflection associated with the river channel.

[0191] The identification marks of fluvial sedimentary microfacies are shown in Table 2.

[0192] Table 2:

[0193] Sedimentary microfacies Seismic reflection characteristics Well logging curve morphology River filling Incised valley filling reflection Box-shaped or bell-shaped GR, sudden increase in resistivity Heart Beach Messy / Humpback Reflections Sawtooth resistivity Beach Lateral accretion pre-accretion reflex Bell-shaped GR, tapering upwards Abandoned river channel weak amplitude filling reflection Top GR value suddenly increased natural embankment Intermittent parallel reflection Low-width toothed GR

[0194] After identifying the deltaic sedimentary microfacies and fluvial sedimentary microfacies, the order of merit of the brine reservoir sand bodies in the deltaic sedimentary system and the order of merit of the brine reservoir sand bodies in the fluvial sedimentary system were determined based on the grain size, thickness of single sand body and sand-to-ground ratio, and the mineralization brine storage space in the deltaic sedimentary system and the mineralization brine storage space in the fluvial sedimentary system were evaluated.

[0195] The development characteristics of sand bodies in different sedimentary microfacies vary greatly. The ideal brine storage space requires sand bodies with good continuity and great thickness. The larger the grain size, the greater the sand-to-formation ratio, and the thickness of a single sand body, the more conducive it is to brine storage.

[0196] (1) Reservoir space of mineralized brine in deltaic sedimentary system

[0197] As shown in Table 3, the order of merit of the brine reservoir sand bodies in the delta sedimentary system is: distributary channel microfacies, mouth bar microfacies, underwater distributary channel microfacies, breach fan microfacies, and sheet sand microfacies.

[0198] Table 3:

[0199]

[0200] (2) Ore-forming brine storage space in river sedimentary system

[0201] As shown in Table 4, the order of quality of brine reservoir sand bodies in the fluvial sedimentary system is: channel fill, center bar, side bar, abandoned channel, and natural levee.

[0202] Table 4:

[0203]

[0204] According to the order of merit of brine reservoir sand bodies in deltaic sedimentary system and that of brine reservoir sand bodies in fluvial sedimentary system, favorable exploration areas are further divided into types.

[0205] For deltaic sedimentary systems, the method for determining secondary favorable exploration areas is as follows:

[0206] If distributary channel microfacies develops in the advantageous exploration area, the advantageous exploration area will be determined as a Class A advantageous exploration area;

[0207] If the advantageous exploration area has developed estuary bar microfacies and underwater distributary channel microfacies, the advantageous exploration area will be determined as a Class B advantageous exploration area;

[0208] If the advantageous exploration area has crevasse fan microfacies and sheet sand microfacies, the advantageous exploration area will be determined as a Class C advantageous exploration area;

[0209] If distributary channel microfacies develops in the favorable exploration area, the favorable exploration area will be determined as a Class A favorable exploration area;

[0210] If the favorable exploration area has developed estuary bar microfacies and underwater distributary channel microfacies, the favorable exploration area will be determined as Class B favorable exploration area;

[0211] If the favorable exploration area has crevasse fan microfacies and sheet sand microfacies, the favorable exploration area will be determined as a Class C favorable exploration area;

[0212] If distributary channel microfacies develops in a generally favorable exploration area, the generally favorable exploration area will be determined as a Class A generally favorable exploration area;

[0213] If the generally favorable exploration area develops estuary bar microfacies and underwater distributary channel microfacies, the generally favorable exploration area will be determined as a Class B generally favorable exploration area;

[0214] If the generally favorable exploration area develops crevasse fan microfacies and sheet sand microfacies, the generally favorable exploration area will be determined as a Class C generally favorable exploration area.

[0215] For fluvial sedimentary systems, the method for determining secondary favorable exploration areas is as follows:

[0216] If the advantageous exploration area develops channel filling microfacies, the advantageous exploration area will be determined as a Class A advantageous exploration area;

[0217] If the advantageous exploration area has core and side shoals, it will be classified as a Class B advantageous exploration area;

[0218] If abandoned river channels and natural levees are developed in the advantageous exploration area, the advantageous exploration area will be determined as a Class C advantageous exploration area;

[0219] If the channel filling microfacies is developed in the favorable exploration area, the favorable exploration area will be determined as a Class A favorable exploration area;

[0220] If a favorable exploration area has core and side shoals, it will be classified as a Class B favorable exploration area.

[0221] If abandoned river channels and natural levees are developed in the favorable exploration area, the favorable exploration area will be determined as a Class C favorable exploration area;

[0222] If the generally favorable exploration area develops channel filling microfacies, the generally favorable exploration area will be determined as a Class A generally favorable exploration area;

[0223] If a generally favorable exploration area has core and side shoals, it will be classified as a Class B generally favorable exploration area;

[0224] If abandoned river channels and natural levees develop in a generally favorable exploration area, the generally favorable exploration area will be determined as a Class C generally favorable exploration area.

[0225] Step S7: Drilling verification is carried out for the determined secondary favorable exploration area, and the K, Li, and B contents are analyzed using the ICP-MS method to detect the physical property parameters of the brine-type lithium potassium boron deposit.

[0226] This application starts from the actual prospecting needs and mineralization characteristics of brine-type lithium potassium boron deposits, focuses on the key area of ​​the tectonic conversion zone of the fault basin, and innovatively proposes a structural control model of multi-factor coupling. Combined with the global paleoclimate database to accurately screen drought events, rapid identification of target layers for prospecting of lithium potassium boron-rich brines in paleoclimate-tectonic coordination is achieved; through the fusion of gravity and magnetic data with seismic data, key elements such as faults, deep faults, volcanic bodies and differential subsidence are integrated to dynamically select favorable mineralization structural units; based on seismic data, structural low-lying areas and sedimentary facies characteristics are characterized to determine favorable exploration areas. Finally, the grade of the lithium potassium boron deposit is determined through drilling verification and ICP-MS high-efficiency detection technology. An integrated evaluation system of "determination of prospecting target layers - optimization of favorable mineralization structural units - optimization of favorable exploration areas - drilling + geochemical verification" is formed, which significantly improves the exploration efficiency of brine-type lithium potassium boron resources in continental fault basins.

[0227] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0228] The above description is merely a specific embodiment of the present application. Any person skilled in the art may easily conceive of variations or substitutions within the technical scope disclosed in this application, and such variations or substitutions shall be within the scope of protection of this application. The scope of protection of this application shall be subject to the scope of protection of the claims.

Claims

1. A method for prospecting brine-type lithium potassium boron deposits in a fault basin structural conversion zone, characterized in that: The method comprises: Using the global paleoclimate database, we screened drought events experienced during the formation and evolution of the fault basin and identified potential target layers for mineral exploration. For the potential prospecting target layer, the type of the prospecting target layer is determined based on the thickness of the evaporite minerals in the prospecting target layer and the proportion of potassium and magnesium salt minerals in the evaporite minerals in the prospecting target layer; Obtaining gravity and magnetic data and seismic data of the fault basin, processing and geologically interpreting the gravity and magnetic data and seismic data to obtain interpreted gravity and magnetic data and interpreted seismic data; identifying faults based on the interpreted gravity and magnetic data and interpreted seismic data, determining a first-level favorable metallogenic tectonic unit and / or identifying deep and large faults, determining a first-level favorable metallogenic tectonic unit and / or identifying volcanic rock bodies, determining a first-level favorable metallogenic tectonic unit; the first-level favorable metallogenic tectonic unit includes a dominant favorable metallogenic tectonic unit, a well-favored metallogenic tectonic unit, and a generally favorable metallogenic tectonic unit; For the first-level favorable metallogenic structural unit, analyzing the differential settlement of adjacent structural units to determine the second-level favorable metallogenic structural unit; For the secondary favorable metallogenic structural units, low-lying areas are identified using seismic data, gravity and magnetic data, drilling data, and outcrop data. The primary favorable exploration areas are determined by combining the fault structures of the fault basin and the distribution range of volcanic rock bodies. For the first-level favorable exploration area, identify fluvial facies, delta facies and sedimentary microfacies to determine the second-level favorable exploration area; Drilling verification is carried out for the determined secondary favorable exploration areas, and the ICP-MS method is used to analyze the K, Li, and B contents and detect the physical properties of brine-type lithium potassium boron deposits.

2. The method according to claim 1, characterized in that The identification of faults and determination of the first-level favorable metallogenic structural units include: Determine the fault type and fault activity intensity of the structural transformation zone of the fault basin based on the gravity and magnetic data of the fault basin; Based on the seismic data of the fault basin, the fault types and fault activity intensity of the tectonic transition zone of the fault basin determined based on gravity and magnetic data are compared, and the fault types, development characteristics and tectonic activity periods of the prospecting target layer and its surrounding layers are analyzed; The first-level favorable mineralization structural unit is determined based on the fault type, development characteristics and tectonic activity period of the prospecting target layer and its surrounding layers.

3. The method according to claim 2, characterized in that The first-level favorable metallogenic structural unit is determined based on the fault type, development characteristics and tectonic activity period of the prospecting target layer and its surrounding layers, including: Determine the activity intensity of normal faults and detachment faults after the formation of the prospecting target layer. If the activity intensity is strong or medium, classify the structural unit where the normal faults and detachment faults are located as a dominant and favorable metallogenic structural unit. Determine the activity intensity of the reverse fault after the formation of the prospecting target layer. If the activity intensity is weak, classify the structural unit where the reverse fault is located as a dominant and favorable metallogenic structural unit. Determine the time when the strike-slip fault and reversal fault undergo tectonic reversal and tectonic strike-slip. If it occurs after the formation of the prospecting target layer, the tectonic unit where the strike-slip fault and reversal fault are located is divided into a dominant and favorable mineralization tectonic unit.

4. The method according to claim 1, wherein The identification of faults and determination of favorable mineralization structural units include: For the structural unit where the fault is located, determine the burial depth of the prospecting target layer and calculate the normal temperature of the prospecting target layer based on the annual average surface temperature; Collect geophysical logging data of the structural unit where the fault is located to determine the well temperature of the target layer for prospecting; If the well temperature of the prospecting target layer is greater than 140% of the normal temperature, the structural unit where the fault is located will be divided into a dominant and favorable mineralization structural unit; If the well temperature of the prospecting target layer is greater than 120% of the normal temperature and less than or equal to 140% of the normal temperature, the structural unit where the fault is located is divided into a favorable mineralization structural unit; If the well temperature of the prospecting target layer is less than or equal to 120% of the normal temperature, the structural unit where the fault is located will be divided into a generally favorable mineralization structural unit.

5. The method according to claim 1, wherein The identification of deep and large faults and determination of the first-level favorable metallogenic structural units include: The spatial distribution and activity of deep faults can be identified through the coordinated analysis of Bouguer gravity anomaly gradient zones and aeromagnetic vertical second-order derivative anomalies. The coherence volume and curvature attributes of seismic data are used to further refine the fault geometry, quantitatively characterize the activity intensity based on the sudden change of the cross-section dip angle and the thickness ratio of the growth layer, and analyze the development characteristics of deep and large faults after the formation of the prospecting target layer; If after the formation of the prospecting target layer, the deep fault appears as a normal fault or a detachment fault, then the structural unit where the deep fault is located is divided into a dominant and favorable metallogenic structural unit; If after the formation of the prospecting target layer, the deep and large fault appears as a strike-slip fault or an inversion fault, then the structural unit where the deep and large fault is located will be divided into a favorable mineralization structural unit.

6. The method according to claim 1, wherein The identification of volcanic rock bodies and determination of primary favorable metallogenic structural units include: Through combined analysis of gravity and magnetic anomalies and vertical derivative processing to enhance boundary identification, the spatial morphology of rock masses can be determined, and volcanic rocks can be distinguished from sedimentary rocks or intrusive rocks. If there is a volcanic rock body in a tectonic unit and its distribution range is greater than or equal to 1 / 5 of the area of ​​the tectonic unit, the tectonic unit is classified as a dominant and favorable metallogenic tectonic unit; If there is a volcanic rock body in a tectonic unit and its distribution range is greater than or equal to 1 / 10 and less than 1 / 5 of the area of ​​the tectonic unit, the tectonic unit is classified as a favorable mineralization tectonic unit; If there is a volcanic rock body in a tectonic unit and its distribution range is less than 1 / 10 of the area of ​​the tectonic unit, the tectonic unit will be classified as a generally favorable mineralization tectonic unit.

7. The method according to claim 1, characterized in that The method of analyzing the differential settlement of adjacent structural units to determine the secondary favorable metallogenic structural unit comprises: For a dominant and favorable metallogenic structural unit, if there is a subsidence difference between adjacent structural units in one stratum below the prospecting target layer, and this relative subsidence difference continues after the formation of the subsidence difference, the footwall is classified as a Class A dominant and favorable metallogenic structural unit; For a dominant and favorable metallogenic structural unit, if there is no settlement difference between adjacent structural units in one stratum below the prospecting target layer, but there is a settlement difference when the prospecting target layer is formed, and this relative settlement difference has continued since then, the footwall is classified as a Class B dominant and favorable metallogenic structural unit; For favorable metallogenic structural units, if there is a difference in settlement between adjacent structural units in one stratum below the prospecting target layer, but this differential settlement ends after the formation of the prospecting target layer, the footwall is classified as a Class A favorable metallogenic structural unit. For favorable metallogenic structural units, if there is no settlement difference between adjacent structural units in one stratum below the prospecting target layer, but there is a settlement difference when the prospecting target layer is formed, and this settlement difference ends after the prospecting target layer is formed, then the footwall is classified as a Class B favorable metallogenic structural unit; For generally favorable metallogenic structural units, if there is no difference in settlement between adjacent structural units and the stratum below the prospecting target layer, but there is differential settlement after the formation of the prospecting target layer, and this relative settlement difference continues thereafter, then the footwall is classified as a type A generally favorable metallogenic structural unit; For generally favorable metallogenic structural units, if there is no settlement difference between the adjacent structural units and the stratum below the prospecting target layer, but there is differential settlement after the formation of the prospecting target layer, but the settlement difference ends thereafter, then the footwall is determined to be a Class B generally favorable metallogenic structural unit.

8. The method according to claim 1, characterized in that For the secondary favorable metallogenic structural units, the low-lying areas are determined using seismic data, gravity and magnetic data, drilling data and outcrop data. Combined with the fault structure of the fault basin and the distribution range of volcanic rock bodies, the primary favorable exploration areas are determined, including: The faults, basement interfaces and sedimentary layer thickness were identified through seismic reflection profile interpretation, and the basement depression area was preliminarily delineated. Process gravity and magnetic data, extract low gravity anomalies and magnetic flat areas, and compare and verify them with seismic basement depth; Seismic interpretation results are used to constrain gravity-magnetic joint inversion and fit measured data to accurately depict the spatial morphology of low-lying areas. Combined with the calibration of borehole data and outcrop data, low-lying areas are comprehensively identified; Compare the spatial relationships between topographic depressions and normal faults and volcanic rock bodies within the same favorable metallogenic tectonic unit; If the low-lying area is located around normal faults and volcanic rock bodies, the low-lying area is determined to be a favorable exploration area; If the low-lying area is located around a normal fault or volcanic rock mass, the low-lying area is determined to be a good and favorable exploration area; If the low-lying area is within 50 km from the normal fault or volcanic rock body, it is determined to be a generally favorable exploration area.

9. The method according to claim 8, characterized in that For the first-level favorable exploration area, the fluvial facies, delta facies and sedimentary microfacies are identified to determine the second-level favorable exploration area, including: Through well-seismic calibration, the sand bodies interpreted by logging are matched with seismic facies, and the fluvial and deltaic facies are identified by combining seismic attributes and regional sedimentary background. Identify deltaic sedimentary microfacies according to the identification marks of deltaic sedimentary microfacies; Identify fluvial sedimentary microfacies based on fluvial sedimentary microfacies identification marks; Based on grain size, single sand body thickness, and sand-to-ground ratio, the order of merit of brine reservoir sand bodies in deltaic sedimentary systems and fluvial sedimentary systems was determined. The order of merit of brine reservoir sand bodies in deltaic sedimentary systems is: distributary channel microfacies, estuary bar microfacies, underwater distributary channel microfacies, breach fan microfacies, and sheet sand microfacies; the order of merit of brine reservoir sand bodies in fluvial sedimentary systems is: channel fill, mid-shoal, side-shoal, abandoned channel, and natural levee. According to the order of merit of the brine reservoir sand bodies in the deltaic sedimentary system and the order of merit of the brine reservoir sand bodies in the fluvial sedimentary system, the secondary favorable exploration areas are determined.

10. The method according to claim 9, characterized in that The order of merit of the brine reservoir sand bodies in the deltaic sedimentary system and the brine reservoir sand bodies in the fluvial sedimentary system is used to determine the secondary favorable exploration areas, including: For deltaic sedimentary systems, the method for determining secondary favorable exploration areas is as follows: If distributary channel microfacies develops in the advantageous exploration area, the advantageous exploration area will be determined as a Class A advantageous exploration area; If the advantageous exploration area has developed estuary bar microfacies and underwater distributary channel microfacies, the advantageous exploration area will be determined as a Class B advantageous exploration area; If the advantageous exploration area has crevasse fan microfacies and sheet sand microfacies, the advantageous exploration area will be determined as a Class C advantageous exploration area; If distributary channel microfacies develops in the favorable exploration area, the favorable exploration area will be determined as a Class A favorable exploration area; If the favorable exploration area has developed estuary bar microfacies and underwater distributary channel microfacies, the favorable exploration area will be determined as Class B favorable exploration area; If the favorable exploration area has crevasse fan microfacies and sheet sand microfacies, the favorable exploration area will be determined as a Class C favorable exploration area; If distributary channel microfacies develops in a generally favorable exploration area, the generally favorable exploration area will be determined as a Class A generally favorable exploration area; If the generally favorable exploration area develops estuary bar microfacies and underwater distributary channel microfacies, the generally favorable exploration area will be determined as a Class B generally favorable exploration area; If the generally favorable exploration area has crevasse fan microfacies and sheet sand microfacies, the generally favorable exploration area will be determined as a Class C generally favorable exploration area; For fluvial sedimentary systems, the method for determining secondary favorable exploration areas is as follows: If the advantageous exploration area develops channel filling microfacies, the advantageous exploration area will be determined as a Class A advantageous exploration area; If the advantageous exploration area has core and side shoals, it will be classified as a Class B advantageous exploration area; If abandoned river channels and natural levees are developed in the advantageous exploration area, the advantageous exploration area will be determined as a Class C advantageous exploration area; If the channel filling microfacies is developed in the favorable exploration area, the favorable exploration area will be determined as a Class A favorable exploration area; If a favorable exploration area has core and side shoals, it will be classified as a Class B favorable exploration area. If abandoned river channels and natural levees are developed in the favorable exploration area, the favorable exploration area will be determined as a Class C favorable exploration area; If the generally favorable exploration area develops channel filling microfacies, the generally favorable exploration area will be determined as a Class A generally favorable exploration area; If a generally favorable exploration area has core and side shoals, it will be classified as a Class B generally favorable exploration area; If abandoned river channels and natural levees develop in a generally favorable exploration area, the generally favorable exploration area will be determined as a Class C generally favorable exploration area.

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