Field section paleomagnetic sampling device and sampling method

Abstract

The invention belongs to the technical field of geological research, and particularly relates to a field section paleomagnetic sampling device and a sampling method. The device comprises a power assembly, a bridging assembly, a sampling tube and a coring tube, a power part in the power assembly comprises a fixed seat and a rotating seat, and the fixed seat is arranged in the center of the rotating seat; the bridging assembly comprises an inner rod, an outer rod, an outer bridge, an inner bridge and a bearing; the inner bridge is in a U shape, the outer bridge is composed of two connecting rods, and the bearing is embedded in the center of the outer rod. Two ends of the inner rod are respectively connected with the fixed seat and the inner bridge; the two end parts of the internal bridging horizontal part are connected with the sampling pipe; a thin-wall bearing is arranged close to the bottom of the sampling tube and is contacted with the coring tube; two ends of the outer rod are respectively connected with the end parts of the rotating seat and the outer bridge, and the other end part of the outer bridge is connected with the coring pipe; a sample box is placed in the sampling tube; and a drill bit is arranged at the bottom end of the coring pipe. According to the invention, efficient and standard sampling can be realized, magnetic pollution in the sampling process is avoided, and the device is convenient to disassemble, assemble and combine and convenient to carry.

Description

Technical Field

[0001] This invention belongs to the field of geological research technology, specifically relating to a field profile paleomagnetic sampling device. Background Technology

[0002] Paleomagnetism is an important branch of Earth science research and a crucial research methodology. It primarily involves measuring the natural remanent magnetism of rocks (including soil) and ancient artifacts, analyzing remanent magnetic parameters (deflection, dip, etc.), studying the historical characteristics of the geomagnetic field and its correlation with geological events, estimating paleomagnetic pole positions, paleolatitudes, and trajectories of landmasses, reconstructing paleogeographic environments, and determining geological ages. In particular, Quaternary paleomagnetic research is a vital tool for paleoclimate and paleogeographic reconstruction, geomagnetic reversal events, and standard dating.

[0003] The first step in paleomagnetic research is collecting qualified paleomagnetic samples. Currently, the common practice for field profile sampling is to manually groove and sample after cleaning and trimming the natural profile, which is labor-intensive and has low sampling efficiency. In existing technologies, some researchers have explored paleomagnetic sampling techniques. The following is a comparative analysis of patent literature highly relevant to this technical solution: Patent CN212482934 U has achieved relatively scientific and efficient paleomagnetic sampling of Quaternary borehole cores. However, Quaternary borehole cores are generally placed horizontally on the ground, and sampling using the aforementioned tools is difficult to perform paleomagnetic sampling on vertical Quaternary geological profiles (steep slopes and cliffs) in the field. The following problems exist: First, the field profiles are vertical and high, making it difficult to keep the tools stably perpendicular to the profile; second, the soil and rock layers in the field profiles are generally quite hard, easily leading to insufficient pressure or directional deviation, resulting in sampling failure; third, the steep slopes are high, requiring ladders, safety ropes, or even cranes to lift technicians to collect samples, limiting the space for force application. In summary, the results for field profile sample collection are not ideal.

[0004] CN214471866 U discloses a paleomagnetic sampling device, providing an apparatus for in-situ paleomagnetic sampling of geological bodies. However, careful analysis revealed three main problems: First, the sampling scenario is unclear: should it be rock or soil samples? Should it be horizontal or vertical drilling? What direction and strata are suitable? Second, the demagnetization of the materials used in the device is inaccurate. Magnetic fields are not limited to iron; substances containing elements such as iron, cobalt, and nickel are also important. To avoid magnetic contamination of the samples, non-magnetic materials such as steel and copper should be used. Third, the most crucial information in paleomagnetic analysis is the magnetic pole direction, which requires precise stratigraphic sequence and cannot be misaligned. This technical solution does not address how to ensure accurate directionality.

[0005] The utility model of CN 217738718 U provides a field sampling device and a sampling system for paleomagnetic samples. The specific sampling operation process of this device is rather cumbersome, and it is not easy to precisely achieve each control step. It is only suitable for relatively soft soil layers during field profile sampling. Summary of the Invention

[0006] To solve the deficiencies of the prior art, the purpose of the present invention is to provide a field profile paleomagnetic sampling device.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions: A field profile paleomagnetic sampling device includes: a power component, a bridging component, and a sampling component; wherein, The power component includes a handle and a power part. The power part includes a fixed seat and a rotating seat, and the fixed seat is at the center position of the rotating seat.

[0008] The bridging component includes: an inner rod, an outer rod, an outer bridge, an inner bridge, and an upper bearing; the inner bridge is in a "C" shape, and the outer bridge is composed of two connecting rods. The upper bearing is embedded in the center of the outer rod; one end of the inner rod passes through the upper bearing and is connected to the fixed seat, and the other end is fixedly connected to the vertical part of the inner bridge. Both ends of the horizontal part of the inner bridge are connected to the sampling tube; a holding spring is arranged at the middle position of the vertical part of the inner bridge, and the lower end of the holding spring is connected to a resin cushion; the holding spring is used to stabilize the sampling box and can be bent 90 degrees. One end of the outer rod is connected to the rotating seat of the power part, the other end of the outer rod is connected to the same-side ends of the two connecting rods, and the other ends of the two connecting rods are connected to the core tube. A sample box for accommodating standard paleomagnetic samples is placed inside the sampling tube. [[ID=**********]] [[ID=**********]]

[0009] Furthermore, there is a lower bearing connecting the lower parts of the core tube and the sampling tube. The inner wall of the upper bearing is connected to the inner rod, and the outer wall is connected to the outer rod; the inner wall of the lower bearing is connected to the sampling tube, and the outer wall is in contact with the core tube. The outer rod drives the outer bridge to rotate, thereby driving the core tube to rotate, so as to keep the relative rotation of the sampling tube and the core tube stable.

[0010] Furthermore, the vertical part of the inner bridging is engraved with directional arrows, and the hand drill is marked with an arrow consistent with the direction of the inner bridging; the horizontal angle detector includes a bubble level, a base, a scale, a pointer, and a rod. The bubble level is placed horizontally in the groove of the base, the scale is located on the base and at the top of the rod, the pointer is connected to the rod, and the rod is inserted into the slot; the rod is connected to the base by a damping shaft, and the rod and the base rotate relative to each other about the center of the scale, while the positions of the scale and the base are relatively fixed, as are the positions of the pointer and the rod. The adjustable bubble level allows for centering of the bubble according to the actual slope when the sampling surface is not vertical (using a damping shaft, the level can be stabilized by adjusting the tilt angle; the rod is connected in two telescopic sections, and when the level base is retracted, it fits snugly against the upper plane), before sampling.

[0011] Furthermore, the lower inner side of the sampling tube is provided with a stepped edge for engaging the sample box, the width of which is the same as the wall thickness of the sample box. The upper end of the sampling tube is provided with a concave arc edge for easy handling of the sample box.

[0012] Furthermore, the bridging components, sampling tubes, core tubes, bearings, and drill bits are all made of non-magnetic materials (containing no elements such as iron, cobalt, or nickel).

[0013] Furthermore, the drill bit is a toothed drill bit.

[0014] Furthermore, the diameter of the core tube is larger than that of the sampling tube, and the outer wall of the core tube is provided with a scale for observing the drilling depth.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following advantages: 1. The sampling tool is made of non-magnetic material, which avoids magnetic contamination during the sampling process and ensures that the magnetic parameters of the sample are accurate and reliable.

[0016] 2. The structure of this device ensures that the inner tube and the core remain stationary, guaranteeing that the stratigraphic sequence direction of the collected samples will not deviate. 3. Sampling quality meets specifications, and sampling efficiency is significantly improved; 4. This device is small and simple, easy to operate, convenient to assemble and disassemble, and easy to carry. Attached Figure Description

[0017] Figure 1 This is an exploded view of the structure of the present invention; Figure 2 This is a schematic diagram of the assembled structure of the present invention; Figure 3 This is a schematic diagram of the power component in this invention; Figure 4 This is a schematic diagram of the swing of the horizontal angle measuring instrument; In the figure, 1 - handle, 2 - fixed seat, 3 - rotating seat, 4 - sampling tube, 5 - core tube, 6 - inner rod, 7 - outer rod, 8 - outer bridge, 9 - inner bridge, 10 - upper bearing, 11 - lower bearing, 12 - holding spring, 13 - step edge, 14 - concave arc edge, 15 - drill bit, 16 - level, 17 - base 17, 18 - dial, 19 - pointer, 20 - insertion rod, 21 - sample box 21. Detailed implementation

[0018] The present invention will be further elaborated in detail below with reference to the accompanying drawings.

[0019] As Figures 1 to 4 shown, a field profile paleomagnetic sampling device includes: a power component, a bridging component, and a sampling component; where The power component includes a handle 1 and a power part. The power part includes a fixed seat 2 and a rotating seat 3. The fixed seat 2 is at the central position of the rotating seat 3. The power is provided by a rechargeable hand drill, and an external battery power supply can be connected when necessary.

[0020] The sampling component includes a sampling tube 4 and a core tube 5; the diameter of the core tube 5 is slightly larger than that of the sampling tube 4, and it is coaxially sleeved outside the sampling tube 4; there is a lower bearing 11 connecting between the lower parts of the core tube 5 and the sampling tube 4.

[0021] The bridging component includes: an inner rod 6, an outer rod 7, an outer bridge 8, an inner bridge 9, and an upper bearing 10; the inner bridge 9 is in a "C" shape, the outer bridge 8 is composed of two connecting rods, and the upper bearing 10 is embedded in the center of the outer rod 7; one end of the inner rod 6 passes through the upper bearing 10 and is connected to the fixed seat 2, and the other end is fixedly connected to the vertical part of the inner bridge 9; Both ends of the horizontal part of the inner bridge 9 are connected to the sampling tube 4; a holding spring 12 is arranged at the middle position of the vertical part of the "C" shape of the inner bridge 9, and the lower end of the holding spring 12 is connected to a resin gasket. Bend the holding spring 12 by 90 degrees before placing the sample box 21, and reset the holding spring to press against the bottom of the sample box 21 after placing the sample box 21.

[0022] One end of the outer rod 7 is connected to the rotating seat 3 of the power part, the other end of the outer rod 7 is connected to the same-side ends of the two connecting rods, and the other ends of the two connecting rods are connected to the core tube 5.

[0023] It is connected to the inner rod 6 through the inner wall of the upper bearing 10 and to the outer rod 7 through the outer wall; the inner wall of the lower bearing 11 is connected to the sampling tube 4, and the outer wall is in contact with the core tube 5. The outer rod 7 drives the outer bridge 8 to rotate, thereby driving the core tube 5 to rotate, so as to keep the relative rotation of the sampling tube 4 and the core tube 5 stable.

[0024] The lower inner side of the sampling tube 4 is provided with a stepped edge 13 for engaging the sample box 21. The width of the edge is the same as the wall thickness of the sample box 21, so that the sampling tube 4 can hold a standard paleomagnetic sample box. The upper end of the sampling tube 4 is provided with a concave arc edge 14 for easy placement and removal of the sample box 21, making it easy for fingers to reach into and remove the sample box 21. Generally, the long axis of the concave arc is located horizontally and perpendicular to the vertical part of the inner bridge, which facilitates the placement and removal of the sample box.

[0025] A toothed drill bit 15 for cutting the rock and soil is provided at the bottom end of the core tube 5; the inner wall of the drill bit 15 is flush with the inner wall of the sampling tube 4, and the drill bit 15 is threadedly connected to the core tube 5. The outer wall of the core tube 5 is provided with graduations for observing the drilling depth. Appropriate drill bits, such as alloy drill bits or diamond drill bits, can be replaced according to the lithology and hardness of the rock and soil in the field. The inner diameter of the drill bit is the same as the inner diameter of the sampling tube.

[0026] A directional arrow is engraved on the vertical part of the inner bridge 9. The top protrusion of the sampling tube 4 has an alignment point engraved along the direction consistent with the arrow. An arrow aligned with the direction of the inner bridge 9 is marked on the upper part of the hand drill handle 1. A horizontal angle detector and a slot are provided on the upper surface of the power assembly. The horizontal angle detector includes a bubble level 16, a base 17, a dial 18, a pointer 19, and a rod 20. The bubble level 16 is horizontally placed in the groove of the base 17. The dial 18 is located at the center below the base 17 and at the top of the rod 20. The pointer 19 is connected to the rod 20, which is inserted into the slot. The rod 20 is connected to the base by a damping pivot. The rod 20 and the base 17 rotate relative to each other around the center of the dial 18. The positions of the dial 18 and the base 17 are relatively fixed, as are the positions of the pointer 19 and the rod 20.

[0027] The bridging components, sampling tube 4, core tube 5, bearings, and drill bits are all made of non-magnetic materials (containing no elements such as iron, cobalt, or nickel).

[0028] When using the above-mentioned sampling device to perform paleomagnetic sampling of soil profiles, the specific steps include: Step 1: Clean the profile: Clean the surface disturbed rock and soil and weeds of the geological profile in the field to reveal the fresh original strata; Step 2: Determine the sampling zone: Based on the profile, select a suitable sampling zone. The width of the sampling zone from top to bottom should not be less than 5 times the sampling diameter (approximately 12cm). Step 3: Trim the sampling zone (points): Trim the sampling zone profile to be vertical and flat. If the profile is not vertical, it can be cut vertically in sections. When the sampling interval is large, it can be trimmed to be vertical and flat at the sampling point.

[0029] Step 4: Assemble the device: Insert the inner bridge 8 and sampling tube 4 into the core tube 5. The inner rod 6 passes through the upper bearing. Connect the drill bit to the core tube 5 and tighten it. Insert the inner rod 6 into the fixing seat and secure it. Connect the outer rod 7 to the rotating seat. (The inner rod 6 is fixed, and the outer rod 7 transmits power.) Step 5: Place the sample box: Bend the top holding spring 12, remove the cover from the sample box 21 and place it with the opening facing down inside the sampling tube 4, so that the opening of the box contacts the step 13 of the sampling tube 4. Adjust it so that the arrow direction on the sample box 21 is consistent with the arrow direction mark on the inner bridge 9 and aligned with the alignment point of the sampling tube 4; then return the top holding spring 12 to the bottom to prevent the core from being pushed out during the sampling process. Step 6: Trial Sampling: Conduct 1-2 trial samplings at non-sampling points. The operator rotates the inner bridge 9 until it is in the same plane as the directional arrow of the power assembly, aligns the drill bit 15, and adjusts the bubble level 16 on the power assembly to center the bubble, ensuring the power assembly is horizontal and the sampling direction is perpendicular to the soil profile. Then, activate the power switch and drill steadily to the sample box depth (approximately 25mm), stop drilling, extract the core, observe if the box orientation has deviated, remove the top holding spring 12, remove the sample box, and observe if the sample meets the requirements. Adjust the drilling depth as needed. Repeat the above process once more to confirm that it meets the test requirements.

[0030] Step 7: Formal Sampling: Following the same process as the "Trial Sampling" above, drill to the sampling depth, then extract the device, remove the sample box, seal it, and complete the single sampling. Repeat this process for each sample until all sampling tasks are completed.

[0031] Step 8: If the profile to be sampled in the field has a certain angle of inclination, place the level angle detector into the slot on the power unit, and adjust the level to the same angle as the slope angle. During the sampling process, observe to keep the bubble in the level as closed as possible. The sampling process is the same as steps 2-7.

[0032] Test case The results of sampling using the sampling device of this invention and existing sampling methods are as follows:

[0033] As shown in the table above, this invention enables one-step sampling with precise location, significantly improving the sampling success rate. The sampling tool is made of non-magnetic material, thus fundamentally avoiding magnetic contamination during the sampling process and ensuring the accuracy and reliability of the sample's magnetic parameters.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A field profile paleomagnetic sampling device, characterized in that, Comprising: A power component, a bridging component, and a sampling component; wherein, The power component includes a handle and a power unit, and the power unit includes a fixed seat and a rotating seat, with the fixed seat at the central position of the rotating seat; The sampling component includes a sampling tube and a core tube; The bridging component includes: an inner rod, an outer rod, an outer bridge, an inner bridge, and an upper bearing; the inner bridge is in a "U" shape, and the outer bridge is composed of two connecting rods, The upper bearing is embedded in the center of the outer rod; one end of the inner rod passes through the upper bearing and is connected to the fixed seat, and the other end is fixedly connected to the vertical part of the inner bridge; Both ends of the horizontal part of the inner bridge are connected to the sampling tube; a holding spring is arranged at the middle position of the vertical part of the inner bridge, and the lower end of the holding spring is connected to an elastic cushion; One end of the outer rod is connected to the rotating seat of the power unit, the other end of the outer rod is connected to the same-side ends of the two connecting rods, and the other ends of the two connecting rods are connected to the core tube; A sample box for accommodating standard paleomagnetic samples is placed inside the sampling tube; a drill bit for cutting rock and soil is provided at the bottom end of the core tube.

2. The field profile paleomagnetic sampling device according to claim 1, characterized in that, The core tube and the lower part of the sampling tube are connected by a lower bearing.

3. The field profile paleomagnetic sampling device according to claim 2, characterized in that, The inner wall of the lower bearing is connected to the sampling tube, and the outer wall is in contact with the core tube.

4. The field profile paleomagnetic sampling device according to claim 1, characterized in that, A step edge for clamping the sample box is provided on the inner side of the lower part of the sampling tube, and the width of the edge is the same as the wall thickness of the sample box; a concave arc edge for facilitating the taking and placing of the sample box is provided at the upper end of the sampling tube.

5. The field profile paleomagnetic sampling device according to claim 1, characterized in that, The drill bit is a toothed drill bit.

6. The field profile paleomagnetic sampling device according to claim 1, characterized in that, The diameter of the core tube is larger than that of the sampling tube, and a scale for observing the sampling depth is provided on the outer wall of the core tube.

7. The field profile paleomagnetic sampling device according to claim 1, characterized in that, Matching direction marks are provided on the inner bridge and the sample box; a horizontal angle detector is provided on the upper plane of the power component, and a slot is also provided on the upper plane; the horizontal angle detector includes a bubble level, a base, a scale disk, a pointer, and a plug rod, the bubble level is horizontally placed in the groove of the base, the scale disk is provided at the center above and below the base and at the top end of the plug rod, the pointer is connected to the plug rod, and the plug rod is inserted into the slot; the plug rod and the base are connected by a damping rotating shaft, the plug rod rotates relative to the base with the center of the scale disk as the center of the circle, the position of the scale disk and the base is relatively fixed, and the position of the pointer and the plug rod is relatively fixed.

8. A method for paleomagnetic sampling of soil profiles using the apparatus described in claim 1, characterized in that, Including the following steps: Step 1, cleaning the section: Clean the surface disturbed rock and soil and weeds of the field geological section to expose the fresh original stratum; Step 2, determining the sampling zone: According to the section situation, select a suitable sampling zone, and the width of the sampling zone from top to bottom should be not less than 5 times the sampling diameter; Step 3, trimming the sampling zone (point): Trim the sampling zone section to be vertically flat. When the section is not upright, it can be cut vertically in segments; when the sampling spacing is large, it is only necessary to trim the sampling point to be vertically flat; Step 4, assembling the device: Insert the inner bridge and the sampling tube into the core tube, the inner rod passes through the upper bearing, then connect the drill bit to the core tube and tighten it, insert the inner rod into the fixed seat and fix it, and connect the outer rod to the rotating seat; Step 5, Place the sample box: Tighten the bent top holding spring, remove the lid of the sample box and place it with the opening facing down inside the sampling tube, so that the opening of the box contacts the stepped edge of the sampling tube. Adjust it so that the arrow on the sample box is consistent with the arrow direction mark of the inner bridge and aligned with the sampling tube alignment point; then return the top holding spring to the bottom of the sample box to prevent the core from being pushed out during the sampling process. Step 6, Trial sampling: Conduct 1-2 trial samplings at non-sampling points; Step 7, Formal Sampling: The process is the same as the "Trial Sampling" above. Drill to the sampling depth, then extract the device, take out the sample box, cover and seal it to complete a single sampling; repeat this process to sample one by one until all sampling tasks are completed. Step 8: If the profile to be sampled in the field has a certain angle of inclination, place the level angle detector into the slot on the power unit, and adjust the level to the same angle according to the slope angle. During the sampling process, observe to keep the bubble in the level as closed as possible. The sampling process is the same as steps 2-7.

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