Salt lake mixed rock naming method

Abstract

The invention provides a naming method for salt lake mixed rock. The naming method comprises the following steps: carrying out rock division by using terrestrial clastic particles, carbonate particles and miscellaneous bases; using 50% as a boundary to distinguish siltstone and limestone; according to a sedimentary structure, the land-derived debris particle component is divided into a stratified structure, a blocky structure, a deformed structure and a wave-formed staggered bedding, siltstone is taken as a basic name when the land-derived debris particle component is larger than 50%, silty sand is taken as a basic name when the land-derived debris particle component is 25%-50%, and silty sand is taken as a basic name when the land-derived debris particle component is 15%-25%; dividing the lithofacies by taking the component characteristics and sedimentary structure characteristics of the rock as a division basis according to the conditions of the rock core and the slice; salt lake lithofacies are divided into three major classes, namely siltstone facies, granular limestone facies and marlstone facies, and are subdivided into ten lithofacies subclasses. The method provides a standardized new thought for lithofacies division in a salt lake deposition system, a standard reference is provided for lithofacies naming through outcrop observation, and a lithofacies division standard is formulated according to the scheme according to the deposition structure, the component content and the like.

Description

Technical Field

[0001] The present application relates to the field of lithofacies classification, and in particular to a naming method for salt lake mixed sedimentary rocks. Background Art

[0002] Lithofacies is the rock or rock combination formed in a certain sedimentary environment. It is the main component of sedimentary facies. Lithofacies division is mainly based on the characteristics of rock mineral components, rock sedimentary structure, color and organic matter content.

[0003] In existing salt lake sedimentation research, sedimentary facies are often divided according to lithofacies and their combination characteristics. However, domestic research on salt lake sedimentary systems started late, and there is no scientific, standardized and quantitative lithofacies division scheme yet. Summary of the Invention

[0004] The present application provides a naming method for salt lake mixed sedimentary rocks, aiming to solve the problem of inconsistent lithofacies classification standards in existing salt lake sedimentary systems.

[0005] The technical solution of this application is:

[0006] A method for naming salt lake mixed sedimentary rocks comprises the following steps:

[0007] S1, based on the characteristics of rock composition, is divided using the three-end-member method, with terrigenous clastic particles, carbonate particles, and matrix (ash / mud + clay) as the three end-members;

[0008] S2, using 50% as the boundary to distinguish siltstone from limestone, taking the mineral component with the highest proportion as the basic name, and based on the different content, minerals with a content of 25-50% are named with a prefix of "something" and minerals with a content of less than 25% are named with a prefix of "something";

[0009] S3 is divided into laminar, massive, deformed and wave-cross bedding according to the sedimentary structure. In the naming process, siltstone is used as the basic name for terrigenous clastic particles with a component of more than 50%, silty is used as the basic name for terrigenous clastic particles with a component of 25%-50%, and silty is used as the basic name for terrigenous clastic particles with a component of 15%-25%.

[0010] S4, based on the basic observations of 1008 meters of macroscopic core and 260 microscopic thin sections in the study area, combined with the basic basis of lithofacies division, the rock component characteristics and special sedimentary structural characteristics are used as the basis for division, and the lithofacies of the study area are divided;

[0011] S5. According to the classification criteria, the salt lake lithofacies are divided into three major categories: siltstone facies, granular limestone facies and marl facies, which are further divided into ten lithofacies subcategories. The ten lithofacies subcategories include four sandstone facies, three granular limestone facies and three marl facies; the four sandstone facies include massive intraclastic siltstone, wavy cross-bedded argillaceous siltstone, deformed tectonic argillaceous siltstone and massive argillaceous siltstone; the three granular limestone facies include deformed tectonic silty granular limestone, laminated silty granular limestone and massive granular limestone; the three marl facies include laminated silt-bearing marlstone, deformed tectonic silty marl and massive marl.

[0012] As a technical solution in the present application, in step S3, particles with a diameter less than 1 cm are defined as laminar, and particles with a diameter greater than 10 cm are defined as massive.

[0013] As a technical solution in the present application, in step S5, the main characteristics of the massive intraclastic siltstone are that it contains intraclasts and has good sorting; the main characteristics of the wavy cross-bedded argillaceous siltstone are red and gray-brown.

[0014] As a technical solution in the present application, in step S5, the main feature of the deformed structure argillaceous siltstone is a high matrix content, and the main feature of the massive argillaceous siltstone is the development of mud gravel and mud debris.

[0015] As a technical solution in the present application, in step S5, the main characteristics of the deformed siltstone limestone are that the main mineral components are silt-grade quartz particles, internal debris, algae and clay minerals. The content of the debris particles is generally 20-45%, which are angular and sub-angular, with general sorting. The quartz is mostly single-crystal quartz, with a content of 15%-40%, and a particle size distribution between 0.04-0.15mm; the content of mud-crystal calcite is generally 10%-20%; the feldspar is mainly plagioclase, with a content of 10%-25%, and a particle size distribution between 0.02mm and 0.08mm; the internal debris particles are the main carbonate particles, with a content of 35-60%, and the particle size of the internal debris particles is 0.05-0.1mm, with good sorting, and the algae are distributed between the carbonate particles. It is transparent under single polarized light and green under fluorescent illumination.

[0016] As a technical solution in the present application, in step S5, the main characteristics of the laminated silty granular limestone are that the content of debris particles is generally 30-50%, which are angular and sub-angular, with general sorting, and the quartz is mostly single-crystal quartz, with a content of 15%-45%, and a particle size distribution between 0.04-0.15mm; the feldspar is mainly plagioclase, with a content of 10%-30%, and a particle size distribution between 0.02mm and 0.08mm; the carbonate particles are mainly internal debris and algal particles, the particle size of the internal debris particles is 0.05-0.1mm, the content is 45-70%, and the sorting is good. It is black and brown under single polarized light and green under fluorescent illumination; the content of mud-crystal calcite is generally 10%-20%, and recrystallization to form fine powder calcite can be seen locally; the main characteristics of the massive granular limestone are uniform structure, containing a small amount of clay minerals, a small amount of felsic minerals, and rare biological debris.

[0017] As a technical solution in the present application, in step S5, the main characteristics of the laminated silt-bearing marl are that the mineral composition is mainly clay minerals, calcite and a small amount of dolomite, the content of silt-grade felsic terrigenous clastic minerals is 15%-25%, the bright laminae are quartz and feldspar, the dark laminae are clay and calcite, and the black clay and organic matter are distributed along the bedding.

[0018] As a technical solution in the present application, in step S5, the main characteristics of the deformed structural siltstone are that the mineral composition is mainly silt-grade felsic terrigenous clastic minerals, intraclasts, algae and clay minerals, among which the content of silt-grade felsic terrigenous clastic minerals is 25%-50%, and more deformed structures are developed.

[0019] As a technical solution in the present application, in step S5, the main characteristics of the massive marl are uniform material, no obvious stratification, and the mineral components are mainly calcite, clay minerals, and silt-grade felsic terrigenous clastic minerals. The clay mineral content is higher than 50% and the silt-grade felsic terrigenous clastic mineral content is less than 15%.

[0020] Beneficial effects of this application:

[0021] The present application provides a naming method for salt lake mixed sedimentary rocks, which emphasizes the joint action of mechanical transportation and chemical genesis, which affects the formation of carbonate materials and reflects its influence on the proportion of each component of salt lake mixed sedimentary rocks. This method proposes some quantitative indicators as classification criteria based on the rock composition and characteristic structure, divides the lithofacies types, and divides the salt lake sedimentary environment more finely. In addition, this method aims to provide a new standardized approach to lithofacies division in salt lake sedimentary systems, provide a standard reference for the naming of lithofacies observed in the field, and conduct research based on the lithofacies division standards formulated by this method according to particle size, sedimentary structure, component content, etc., to provide reference assistance for the study of such salt lake sedimentary systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the implementation methods of the present application, the following is a brief introduction to the drawings required for use in the implementation methods. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the process for naming salt lake mixed sedimentary rocks provided in an embodiment of the present application;

[0024] Figure 2 This is an electron microscope thin section image of clastic siltstone in a massive structure at a depth of 2337.3 m in the research well provided in the examples of this application;

[0025] Figure 3 This is an electron microscope thin section image of clastic siltstone in a massive structure at a depth of 2337.3 m in the research well provided in the examples of this application;

[0026] Figure 4 Schematic diagram of the wavy and interbedded muddy siltstone at a depth of 1328.91 m in the research well provided in the examples of this application;

[0027] Figure 5 Schematic diagram of the wavy and interbedded muddy siltstone at a depth of 1031.10 m in the research well provided in the examples of this application;

[0028] Figure 6 Schematic diagram of the wavy and interbedded muddy siltstone at a depth of 2916.52 m in the research well provided in the examples of this application;

[0029] Figure 7 This is an electron microscope thin section image of deformed argillaceous siltstone at a depth of 2644.41 m in the research well provided in the examples of this application;

[0030] Figure 8 This is an electron microscope thin section image of deformed argillaceous siltstone at a depth of 2644.41 m in the research well provided in the examples of this application;

[0031] Figure 9 A schematic diagram of a deformed structure muddy siltstone core at a depth of 2644.41 m in the research well provided in the embodiments of the present application;

[0032] Figure 10 This is an electron microscope thin section image of massive muddy siltstone at a depth of 2219.77 m in the research well provided in the examples of this application;

[0033] Figure 11 This is an electron microscope thin section image of massive muddy siltstone at a depth of 2219.77 m in the research well provided in the examples of this application;

[0034] Figure 12 A schematic diagram of a massive muddy siltstone core at a depth of 2219.77 m in a research well provided in an embodiment of the present application;

[0035] Figure 13 This is an electron microscope thin section image of deformed silty granular limestone at a depth of 1300.89 m in the research well provided in the examples of this application;

[0036] Figure 14 This is an electron microscope thin section image of deformed silty granular limestone at a depth of 1300.89 m in the research well provided in the examples of this application;

[0037] Figure 15 This is an electron microscope thin section image of deformed silty granular limestone at a depth of 1300.89 m in the research well provided in the examples of this application;

[0038] Figure 16 This is an electron microscope thin section image of the laminated silty granular limestone at a depth of 1307 m in the research well provided in the examples of this application;

[0039] Figure 17 This is an electron microscope thin section image of the laminated silty granular limestone at a depth of 1307 m in the research well provided in the examples of this application;

[0040] Figure 18 Schematic diagram of a laminated silty granular limestone core at a depth of 1307 m in a research well provided in an embodiment of the present application;

[0041] Figure 19 This is an electron microscope thin section image of massive structure granular limestone at a depth of 2348.38m in the research well provided in the examples of this application;

[0042] Figure 20 This is an electron microscope thin section image of massive structure granular limestone at a depth of 2348.38m in the research well provided in the examples of this application;

[0043] Figure 21 This is an electron microscope thin section image of the deformed silty marl at a depth of 2350.88 m in the research well provided in the examples of this application;

[0044] Figure 22 This is an electron microscope thin section image of the deformed silty marl at a depth of 2350.88 m in the research well provided in the examples of this application;

[0045] Figure 23 This is an electron microscope thin section image of the laminated silt-bearing marl at a depth of 948.89 m in the research well provided in the examples of this application;

[0046] Figure 24 This is an electron microscope thin section image of the laminated silt-bearing marl at a depth of 948.89 m in the research well provided in the examples of this application;

[0047] Figure 25 Schematic diagram of a core of laminated silt-bearing marl at a depth of 948.89 m in a research well provided in an embodiment of the present application;

[0048] Figure 26 This is an electron microscope thin section image of massive marl at a depth of 2858.65 m in the research well provided in the examples of this application;

[0049] Figure 27 Schematic diagram of massive marl core at a depth of 2858.65m in the research well provided in the examples of this application. DETAILED DESCRIPTION

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without making any creative efforts shall fall within the scope of protection of the present application.

[0052] Example:

[0053] Please refer to Figure 1 , with reference Figures 2 to 27 In the embodiment of the present application, a method for naming salt lake mixed sedimentary rocks is provided, comprising the following steps:

[0054] S1, based on the characteristics of rock composition, is divided using the three-end-member method, with terrigenous clastic particles, carbonate particles, and matrix (ash / mud + clay) as the three end-members;

[0055] S2, using 50% as the boundary to distinguish siltstone from limestone, taking the mineral component with the highest proportion as the basic name, and based on the different content, minerals with a content of 25-50% are named with a prefix of "something" and minerals with a content of less than 25% are named with a prefix of "something";

[0056] S3 is divided into laminar, massive, deformed and wave-cross bedding according to the sedimentary structure. In the naming process, siltstone is used as the basic name for terrigenous clastic particles with a component of more than 50%, silty is used as the basic name for terrigenous clastic particles with a component of 25%-50%, and silty is used as the basic name for terrigenous clastic particles with a component of 15%-25%.

[0057] S4, based on the basic observations of 1008 meters of macroscopic core and 260 microscopic thin sections in the study area, combined with the basic basis of lithofacies division, the rock component characteristics and special sedimentary structural characteristics are used as the basis for division, and the lithofacies of the study area are divided;

[0058] S5. According to the classification criteria, the salt lake lithofacies are divided into three major categories: siltstone facies, granular limestone facies and marl facies, which are further divided into ten lithofacies subcategories. The ten lithofacies subcategories include four sandstone facies, three granular limestone facies and three marl facies; the four sandstone facies include massive intraclastic siltstone, wavy cross-bedded argillaceous siltstone, deformed tectonic argillaceous siltstone and massive argillaceous siltstone; the three granular limestone facies include deformed tectonic silty granular limestone, laminated silty granular limestone and massive granular limestone; the three marl facies include laminated silt-bearing marlstone, deformed tectonic silty marl and massive marl.

[0059] It should be noted that in step S3, particles with a diameter less than 1 cm are defined as laminar, and particles with a diameter greater than 10 cm are defined as massive.

[0060] Furthermore, in step S5, the main characteristics of massive intraclastic siltstone are the presence of intraclasts and good sorting, while the main characteristics of wavy cross-bedding argillaceous siltstone are red and gray-brown. The main characteristics of deformational argillaceous siltstone are high matrix content, and the main characteristics of massive argillaceous siltstone are the development of mud gravels and mud clasts.

[0061] Furthermore, in step S5, the main characteristics of the deformed silty grain limestone are that the main mineral components are silt-grade quartz particles, intraclasts, algae particles, and clay minerals. The fraction of the intraclasts is generally 20-45%, with angular and sub-angular shapes and good sorting. The quartz is mostly single-crystal quartz, accounting for 15%-40%, with a particle size distribution between 0.04-0.15 mm. The content of micrite calcite is generally 10%-20%. The feldspar is mainly plagioclase, accounting for 10%-25%, with a particle size distribution between 0.02 mm and 0.08 mm. The intraclasts are mainly carbonate particles, accounting for 35-60%, with a particle size of 0.05-0.1 mm and good sorting. The algae particles are distributed among the carbonate particles. They are transparent under single polarized light and green under fluorescent illumination.

[0062] In step S5, the main characteristics of the laminated silty grainstone are that the content of clastic particles is generally 30-50%, with angular and sub-angular shapes and good sorting. The quartz is mostly single-crystal quartz, with a content of 15%-45% and a particle size distribution between 0.04mm and 0.15mm. The feldspar is mainly plagioclase, with a content of 10%-30% and a particle size distribution between 0.02mm and 0.08mm. The carbonate particles are mainly intraclasts and algal particles. The intraclast particles have a particle size of 0.05-0.1mm and a content of 45-70%. They are well sorted and appear black and brown under single polarized light and green under fluorescent illumination. The content of micritic calcite is generally 10%-20%, with recrystallization to form fine powder calcite in some areas. The main characteristics of the massive grainstone are a uniform structure, containing small amounts of clay minerals and felsic minerals, and rare bioclasts.

[0063] In step S5, the main characteristics of the laminated silt-bearing marl are that the mineral composition is mainly clay minerals, calcite and a small amount of dolomite, the content of silt-grade felsic terrigenous clastic minerals is 15%-25%, the light-colored laminae are quartz and feldspar, the dark-colored laminae are clay and calcite, and the black clay and organic matter are distributed along the bedding.

[0064] In step S5, the main characteristics of the deformation structure silt marl are that the mineral composition is mainly silt-grade felsic terrigenous clastic minerals, intraclasts, algae and clay minerals, among which the content of silt-grade felsic terrigenous clastic minerals is 25%-50%, and more deformation structures are developed.

[0065] In step S5, the main characteristics of the massive marl are uniform material, no obvious stratification, and the mineral components are mainly calcite, clay minerals, and silt-grade felsic terrigenous clastic minerals. The clay mineral content is higher than 50% and the silt-grade felsic terrigenous clastic mineral content is lower than 15%.

[0066] In summary, the present application provides a method for naming salt lake mixed sedimentary rocks, which emphasizes the joint action of mechanical transportation and chemical genesis, which affects the formation of carbonate materials and reflects its influence on the proportion of each component of salt lake mixed sedimentary rocks. This method proposes some quantitative indicators as classification criteria based on the composition and characteristic structure of the rocks, divides the lithofacies types, and divides the salt lake sedimentary environment more finely. In addition, this method aims to provide a new standardized approach to lithofacies division in salt lake sedimentary systems, provide a standard reference for naming lithofacies observed in the field, and conduct research based on the lithofacies division standards formulated by this method according to particle size, sedimentary structure, component content, etc., to provide reference assistance for the study of such salt lake sedimentary systems.

[0067] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for naming salt lake mixed sedimentary rocks, characterized in that: The following steps are involved: S1, based on the characteristics of rock composition, the rocks are divided into three end members: terrigenous clastic particles, carbonate particles and matrix; S2, using 50% as the dividing line to distinguish siltstone from limestone, taking the mineral component with the highest proportion as the basic name, and based on the different content, minerals with a content of 25-50% are named with a prefix of "something" and minerals with a content of less than 25% are named with a prefix of "something"; S3 is divided into laminar, massive, deformed and wave-cross bedding according to the sedimentary structure. In the naming process, siltstone is used as the basic name for terrigenous clastic particles with a component of more than 50%, silty is used as the basic name for terrigenous clastic particles with a component of 25%-50%, and silty is used as the basic name for terrigenous clastic particles with a component of 15%-25%. S4, based on the observation of cores and microscopic thin sections in the study area, combined with the basis of lithofacies division, the rock composition characteristics and sedimentary structural characteristics are used as the basis for division, and the lithofacies of the study area are divided; S5. According to the classification criteria, the salt lake lithofacies are divided into three major categories: siltstone facies, granular limestone facies and marl facies, which are further divided into ten lithofacies subcategories. The ten lithofacies subcategories include four sandstone facies, three granular limestone facies and three marl facies; the four sandstone facies include massive intraclastic siltstone, wavy cross-bedded argillaceous siltstone, deformed tectonic argillaceous siltstone and massive argillaceous siltstone; the three granular limestone facies include deformed tectonic silty granular limestone, laminated silty granular limestone and massive granular limestone; the three marl facies include laminated silt-bearing marlstone, deformed tectonic silty marl and massive marl.

2. The method for naming salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S3, particles with a diameter less than 1 cm are defined as laminar, and particles with a diameter greater than 10 cm are defined as massive.

3. The naming method of salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S5, the main characteristics of massive intraclastic siltstone are the presence of intraclasts and good sorting; the main characteristics of wavy cross-bedded argillaceous siltstone are reddish brown and grayish brown; the main characteristics of deformed argillaceous siltstone are high matrix content; the main characteristics of massive argillaceous siltstone are the development of mud gravels and mud clasts.

4. The method for naming salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S5, the main characteristics of the deformed silty granular limestone are that the main mineral components are silt-grade quartz particles, internal debris, algae and clay minerals; the content of debris particles is 20-45% and they are angular and sub-angular, and the sorting is general, the quartz is mostly single crystal quartz and the content is 15%-40%, and the particle size distribution is between 0.04-0.15mm; the content of mud crystal calcite is 10%-20%; the feldspar is mainly plagioclase, the content is 10%-25%, and the particle size distribution is between 0.02mm and 0.08mm; the content of internal debris particles is 35-60% and the particle size is 0.05-0.1mm, the sorting is good, the algae are distributed between the carbonate particles, it is transparent under single polarized light and green under fluorescent illumination.

5. The method for naming salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S5, the main characteristics of the laminated silty granular limestone are that the content of debris particles is 30-50%, and they are angular and sub-angular, and the sorting is general. The quartz is mostly single crystal quartz, with a content of 15%-45% and a particle size distribution between 0.04-0.15 mm; the feldspar is mainly plagioclase with a content of 10%-30% and a particle size distribution between 0.02 mm and 0.08 mm; the carbonate particles are mainly intraclasts and algal particles, the particle size of the intraclast particles is 0.05-0.1 mm, the content is 45-70%, and the sorting is good. They are black and brown under single polarized light and green under fluorescent illumination; the content of mud-crystal calcite is generally 10%-20%, and recrystallization to form fine powder calcite can be seen locally; the main characteristics of the massive granular limestone are uniform structure, containing a small amount of clay minerals and a small amount of felsic minerals, and rare bioclasts.

6. The method for naming salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S5, the main characteristics of the laminated silt-bearing marl are that the mineral composition is mainly clay minerals, calcite and a small amount of dolomite, the content of silt-grade felsic terrigenous clastic minerals is 15%-25%, the light-colored laminae are quartz and feldspar, the dark-colored laminae are clay and calcite, and the black clay and organic matter are distributed along the bedding.

7. The method for naming salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S5, the main characteristics of the deformation structure siltstone are that the mineral composition is mainly silt-grade felsic terrigenous clastic minerals, intraclasts, algae and clay minerals, the content of silt-grade felsic terrigenous clastic minerals is 25%-50% and more deformation structures are developed.

8. The method for naming salt lake mixed sedimentary rocks according to claim 1, characterized in that: In step S5, the main characteristics of the massive marl are uniform material, no obvious stratification, and the mineral components are mainly calcite, clay minerals, and silt-grade felsic terrigenous clastic minerals. The clay mineral content is higher than 50%, and the silt-grade felsic terrigenous clastic mineral content is lower than 15%.

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