A method for identifying ideal maifanite parent rock

Abstract

The application discloses an ideal maherite mother rock identification method, and belongs to the technical field of rock mineral analysis, and comprises the following steps: preparing a rock sample into a rock slice; judging whether the rock sample has a porphyritic structure and whether the mineral composition meets a first preset condition; using a rock point statistical method to statistically analyze the mineral composition in the rock slice to obtain percentage data of plagioclase, potash feldspar and quartz; mapping the statistical result to an intrusive rock QAP classification diagram to judge whether the mapping result falls within a preset lithology range; preparing part of the remaining rock sample into a test sample and performing whole-rock geochemical testing to obtain whole-rock geochemical testing data; and judging whether the second preset condition is met according to the whole-rock geochemical testing data, and if yes, determining that the rock sample is an ideal maherite mother rock. The identification method is simple to operate, does not require complex high-precision equipment and instruments, and has high accuracy.

Description

Technical Field

[0001] This invention relates to the field of rock and mineral analysis technology, specifically a method for identifying ideal maifanite parent rock. Background Technology

[0002] Maifan stone, a mineral-based traditional Chinese medicine, has been used in clinical treatment since the Song Dynasty. It gets its name from its resemblance to cooked barley rice. Maifan stone is mainly composed of two parts: phenocrysts and matrix. The phenocrysts are the grains remaining after the weathering and alteration of the parent rock (mainly plagioclase and potassium feldspar, with a small amount of quartz), rich in various elements beneficial to the human body. The matrix has a porous, sieve-like structure, which not only helps dissolve essential macro and micro elements in water but also adsorbs heavy metals, bacteria, and odors. It also has a bidirectional pH-regulating function, making it a non-metallic mineral resource with significant social and economic benefits.

[0003] Common maifanite parent rocks are mainly monzonite porphyry and quartz monzonite porphyry, with plagioclase, potassium feldspar, and quartz as the main minerals, and amphibole and biotite as secondary minerals. In addition, granite monzonite porphyry and diorite porphyry are also considered maifanite parent rocks. Maifanite can be formed through long-term weathering and alteration of the above parent rocks, or its mineralization and adsorption properties can be similar to maifanite by adjusting the activation level of the parent rock. Local standards in Inner Mongolia Autonomous Region and Henan Province define maifanite parent rock (the bedrock mentioned in the original text) as monzonite porphyry. From a practical application perspective, quartz monzonite porphyry is also considered an ideal maifanite parent rock.

[0004] Therefore, identifying the type of parent rock of maifanite plays a decisive role in its effectiveness. There are over a dozen representative maifanite producing areas in my country, most of which are formed from weathered (quartz) monzonite porphyry. Some maifanite producing areas (such as Jiayin in Heilongjiang and Siming Mountain in Zhejiang) also classify weathered porphyritic granite and diorite as maifanite. Considering that the effective components of maifanite mainly come from feldspar minerals, high levels of minerals such as quartz (not less than 20%) and amphibole (not less than 10%) will restrict the mineralization and adsorption properties of maifanite. Limiting the ideal parent rock type of maifanite to monzonite porphyry and quartz monzonite porphyry will help further improve the utilization efficiency of maifanite.

[0005] Currently, the identification methods for maifanite parent rocks mainly include visual observation, observation under a polarizing microscope, and whole-rock geochemical testing. Visual and polarizing microscope observations of rock samples can determine their lithology, while whole-rock geochemical data can be used to further confirm whether they conform to the chemical composition characteristics of an ideal maifanite parent rock. However, existing identification methods have the following shortcomings: First, the identification process lacks systematicity. In current technology, polarizing microscope observation and whole-rock geochemical testing are often used as independent identification methods, lacking a standardized process that organically combines the two. This makes the identification results susceptible to subjective factors, resulting in insufficient accuracy and repeatability. Second, there is a lack of clear quantitative judgment standards. Existing identification methods largely rely on the experience and judgment of the identification personnel, lacking unified quantitative thresholds for mineral content ratios and rock chemical composition parameters, making it difficult for different identification subjects to reach consistent identification conclusions. Summary of the Invention

[0006] The purpose of this invention is to provide a method for identifying ideal maifanite parent rock, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for identifying an ideal maifanite parent rock includes the following steps: Collect rock samples to be identified and prepare rock thin sections from the rock samples; The rock thin section was observed under a polarizing microscope to determine whether the rock sample had a porphyritic structure and whether the mineral composition met the first preset condition. When the rock sample meets the first preset condition, the mineral composition in the rock thin section is statistically analyzed using the rock point statistical method to obtain the percentage data of plagioclase, potassium feldspar and quartz. Based on the percentage data, the statistical results are plotted onto the QAP classification map of intrusive rocks to determine whether the plotting results fall within the preset lithology range; When the mapping results fall within the preset lithological range, some of the remaining rock samples are taken to prepare test specimens and whole-rock geochemical tests are performed to obtain whole-rock geochemical test data. Based on the whole-rock geochemical test data, determine whether the second preset condition is met. If so, the rock sample is determined to be an ideal maifanite parent rock.

[0008] Furthermore, the thickness of the rock sheet is 0.01-0.05 mm.

[0009] Furthermore, the first preset condition is that the rock sample has a porphyritic structure, and the content of feldspar minerals is greater than 70 wt%, and the content of quartz is less than 20 wt%; the feldspar minerals include plagioclase and potassium feldspar.

[0010] Furthermore, the rock point statistical method specifically includes the following steps: Draw several straight lines on the rock thin section along the direction parallel to the long side of the section, with a spacing of 0.5-1 cm between adjacent lines; align the selected straight lines with the transverse part of the crosshairs of the polarizing microscope eyepiece, move the rock thin section at a constant speed along the X-axis of the stage, and record the mineral particles that pass through the intersection of the crosshairs each time, and accumulate a preset number of mineral particles; wherein, the mineral particles include plagioclase, potassium feldspar and quartz.

[0011] Furthermore, the preset lithological range is: the range of monzonite or quartz monzonite in the QAP classification map of intrusive rocks.

[0012] Furthermore, the whole-rock geochemical tests were conducted using an X-ray fluorescence spectrometer.

[0013] Furthermore, the method for preparing test samples from a portion of the remaining rock samples is as follows: grind the remaining rock samples into powder, and then prepare them into test samples.

[0014] Furthermore, the second preset condition is: the SiO2 content is in the range of 60-70 wt%, the sum of the Na2O and K2O contents is in the range of 5-10 wt%, and the Rittmann index σ < 3.3.

[0015] The method for identifying ideal maifanite parent rock provided by this invention, based on the unique structure and lithology of maifanite parent rock, ensures the quality of maifanite parent rock from the source from a mineral identification perspective, thereby improving its utilization efficiency. This invention, by limiting the range of geochemical parameters, can further accurately identify whether a rock sample belongs to the ideal maifanite parent rock. Furthermore, the identification method provided by this invention is simple to operate, requires no complex high-precision equipment or instruments, and has high accuracy. Attached Figure Description

[0016] Figure 1 A schematic flowchart illustrating the method for identifying ideal maifanite parent rock provided in an embodiment of the present invention.

[0017] Figure 2 A photograph of a maifanite parent rock sample under a polarizing microscope (orthogonal polarization) provided in an embodiment of the present invention.

[0018] Figure 3 Photographs of scribing rock sections provided for embodiments of the present invention.

[0019] Figure 4 A photograph of a scribing rock section under a polarizing microscope (including crosshairs, orthogonally polarized light) provided for an embodiment of the present invention.

[0020] Figure 5This is a schematic diagram of the QAP classification of intrusive rocks (Streckeisen, 1976) and the lithological range of an ideal maifanite parent rock (shaded area). Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] In one embodiment of the present invention, a method for identifying an ideal maifanite parent rock is provided, comprising the following steps: preparing a thin rock section (thickness controlled at 0.01-0.05 mm, and ensuring visibility under a polarizing microscope) from a collected rock sample to be identified; observing the thin rock section under a polarizing microscope to determine whether the rock sample has a porphyritic structure and whether the mineral composition meets a first preset condition; when the rock sample meets the first preset condition, statistical analysis of the mineral composition in the thin rock section is performed using a rock point statistical method to obtain percentage data of plagioclase, potassium feldspar, and quartz; based on the percentage data, the statistical results are plotted onto an intrusive rock QAP classification map to determine whether the plotting results fall within a preset lithological range; when the plotting results fall within the preset lithological range, some of the remaining rock sample is ground into powder, then prepared into a test sample, and whole-rock geochemical testing is performed using an X-ray fluorescence spectrometer (XRF) to obtain whole-rock geochemical test data; based on the whole-rock geochemical test data, it is determined whether a second preset condition is met, and if so, the rock sample is determined to be an ideal maifanite parent rock.

[0023] In a preferred embodiment of the present invention, the first preset condition is: the rock sample has a porphyritic structure, and the content of feldspar minerals (including plagioclase and potassium feldspar) is greater than 70 wt%, and the quartz content is less than 20 wt%.

[0024] In a preferred embodiment of the present invention, the above-mentioned rock point statistical method specifically includes the following steps: Draw several straight lines on the rock thin section along the direction parallel to the long side of the section, with a spacing of 0.5-1 cm between adjacent lines; align the selected straight lines with the transverse part of the crosshairs of the polarizing microscope eyepiece, and move the rock thin section at a constant speed along the straight line direction (i.e., the X-axis direction of the stage), recording the plagioclase, potassium feldspar, and quartz mineral grains (only plagioclase, potassium feldspar, and quartz) that pass through the intersection of the crosshairs each time, and accumulating a preset number (no less than 100) of mineral grains.

[0025] In a preferred embodiment of the present invention, the above-mentioned preset lithological range is: the range of monzonite or the range of quartz monzonite in the QAP classification map of intrusive rocks.

[0026] In a preferred embodiment of the present invention, the second preset condition is as follows: the SiO2 content is in the range of 60-70 wt%, the sum of the Na2O and K2O contents is in the range of 5-10 wt%, and the Rittmann index σ < 3.3 (i.e., whether it belongs to calc-alkaline rocks); wherein, the formula for calculating the Rittmann index is as follows: σ = (Na₂O + K₂O) 2 / (SiO2-43).

[0027] Unless otherwise specified, all instruments involved in the following embodiments are commercially available products and can be purchased through commercial channels. The invention will be described in detail below through specific embodiments in practical applications.

[0028] Example 1: As Figure 1 As shown, this embodiment provides a method for identifying an ideal maifanite parent rock, the specific steps of which include the following process: S1. Collect maifanite parent rock samples in the field, select samples with obvious porphyritic structure and abundant plagioclase and potassium feldspar minerals, grind them into thin rock sections that can be observed under a polarizing microscope, and control the thickness of the rock thin sections to about 0.03 mm, referring to "Technical Specification for Rock and Mineral Identification Part 2: Rock Thin Section Sample Preparation" (DZ / T 0275.2-2015). S2. Observe the cut rock sections under a polarizing microscope, focusing on whether the feldspar grains have obvious porphyritic structures (such as...). Figure 2 As shown in the left image, the mineral grains are predominantly plagioclase and potassium feldspar (roughly estimated to be >70 wt%), supplemented with a certain amount of quartz (roughly estimated to be <20 wt%). Under crossed polarizing microscopes, plagioclase exhibits polysynthetic twinning characteristics, while potassium feldspar exhibits Karl von Willebrand twinning characteristics; both have relatively dirty surfaces. Quartz is irregularly shaped with a clean and smooth surface; its microscopic features are shown in the reference image. Figure 2 The image on the right; S3. The mineral composition of the rock thin section is statistically analyzed using the rock point statistical method: several straight lines are drawn along the long side of the thin section (e.g., Figure 3 (As shown) The straight lines are spaced a certain distance (0.5-1cm), and the selected straight line is aligned with the horizontal part of the crosshairs of the microscope eyepiece (e.g.) Figure 4 As shown), the thin plate is moved at a constant speed along a straight line (i.e., the X-axis direction of the stage), and each plagioclase, potassium feldspar, or quartz that passes through the intersection of the crosshairs is recorded, and at least 100 mineral particles are counted in total. S4. Calculate the proportions of plagioclase, potassium feldspar, and quartz based on the statistical results, and plot the results onto the QAP classification chart of intrusive rocks (e.g., Figure 5 (As shown). If the sample is placed within the range of monzonite or quartz monzonite, it can be preliminarily determined that it is an ideal parent rock for maifanite.

[0029] S5. To further determine whether the test sample belongs to the ideal maifanite parent rock, whole-rock geochemical analysis is required. A portion of the remaining test sample was selected, ground into powder, and prepared into test specimens for testing using an XRF instrument.

[0030] S6. Analyze the test data obtained in step S5: If SiO2 is in the range of 60-70wt%, the sum of Na2O and K2O content is between 5-10wt%, and the Rittmann index calculation result shows that the σ value belongs to calc-alkaline rocks (i.e. σ<3.3), then the sample can be finally determined to be an ideal maifanite parent rock.

[0031] In summary, the identification method provided by the embodiments of the present invention is simple to operate, requires no complex and sophisticated equipment, and has high accuracy. It can accurately locate the ideal maifanite parent rock from both the perspectives of mineral composition and geochemical characteristics.

[0032] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification.

Claims

1. A method for identifying an ideal maifanite parent rock, characterized in that, Includes the following steps: Collect rock samples to be identified and prepare rock thin sections from the rock samples; The rock thin section was observed under a polarizing microscope to determine whether the rock sample had a porphyritic structure and whether the mineral composition met the first preset condition. When the rock sample meets the first preset condition, the mineral composition in the rock thin section is statistically analyzed using the rock point statistical method to obtain the percentage data of plagioclase, potassium feldspar and quartz. Based on the percentage data, the statistical results are plotted onto the QAP classification map of intrusive rocks to determine whether the plotting results fall within the preset lithology range; When the mapping results fall within the preset lithological range, some of the remaining rock samples are taken to prepare test specimens and whole-rock geochemical tests are performed to obtain whole-rock geochemical test data. Based on the whole-rock geochemical test data, determine whether the second preset condition is met. If so, the rock sample is determined to be an ideal maifanite parent rock.

2. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The thickness of the rock sheet is 0.01-0.05 mm.

3. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The first preset condition is that the rock sample has a porphyritic structure and the content of feldspar minerals is greater than 70 wt% and the content of quartz is less than 20 wt%; the feldspar minerals include plagioclase and potassium feldspar.

4. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The rock point statistical method specifically includes the following steps: Draw several straight lines on the rock thin section along the direction parallel to the long side of the section, with a spacing of 0.5-1 cm between adjacent lines; align the selected straight lines with the transverse part of the crosshairs of the polarizing microscope eyepiece, move the rock thin section at a constant speed along the X-axis of the stage, and record the mineral particles that pass through the intersection of the crosshairs each time, and accumulate a preset number of mineral particles; wherein, the mineral particles include plagioclase, potassium feldspar and quartz.

5. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The preset lithological range is: the range of monzonite or quartz monzonite in the QAP classification map of intrusive rocks.

6. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The whole-rock geochemical tests were conducted using X-ray fluorescence spectrometry.

7. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The method for preparing test specimens from a portion of the remaining rock sample is as follows: grind the remaining rock sample into powder, and then prepare it into test specimens.

8. The method for identifying the ideal maifanite parent rock according to claim 1, characterized in that, The second preset condition is: the SiO2 content is in the range of 60-70 wt%, the sum of the Na2O and K2O contents is in the range of 5-10 wt%, and the Rittmann index σ < 3.3.

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