Project III/KLOC-0: 50,000 regional geological fill

1.

The purpose of the measured profile is to divide strata and intrusions, understand lithologic characteristics, stratum thickness, stratum fossil content, rock assemblage characteristics of various stratigraphic units and different lithofacies, and determine mapping units.

2. Requirements

(1) General requirements for measured profiles

In order to ensure the accuracy of stratigraphic division, each map should have at least one measured section in each era. For stratigraphic units with large lithofacies changes, the control of measured sections should be strengthened to meet the needs of compiling comprehensive stratigraphic histogram by framing. When there are measured profiles (including those measured by regional survey, general survey and exploration of mining areas and scientific work) that meet the working requirements of 1:50000 in the survey area, they can be used in part or in whole, or they can be used after necessary supplementary work according to the principle of filling vacancies.

When there are typical sections with a high degree of research in the adjacent area, but the lithology and lithofacies changes are not obvious, the research degree of the measured sections of the map sheet can be appropriately reduced.

When studying the measured profile of strata, we should strengthen the study of sedimentary rocks and sedimentary facies, pay attention to the collection and analysis of facies markers such as bedding types, occurrence factors, paleontology and paleoecological characteristics, and divide the strata closely related to mineralization into subfacies. Stratigraphic description generally consists of basic description and supplementary description. The basic description includes the color, texture, structure, mineral composition and basic name of the rock (such as dark gray thick to medium thick layered fine-grained dolomite limestone); Supplementary descriptions include fossil horizon, ecology and abundance, mineral composition changes, rock structure and thickness, stratigraphic contact, geomorphology and hydrology and other supplements.

During the profile measurement, all kinds of analysis and identification samples should be collected systematically.

The layering accuracy of stratigraphic section should fully consider sedimentary rhythm, lithologic changes and fossil characteristics. The segmentation ratio should be determined according to the layering accuracy. In general, the minimum single layer thickness on the section is not less than1mm. The scale of sedimentary stratum profile is roughly determined as1.500 ~1.2000; The profile scale of metamorphic rock area is 1∶5000.

It is allowed to splice measurement contours from segmented measurement data. Under the condition that the profile outcrop can meet the minimum practical requirements, necessary mountain engineering is adopted to expose the top and bottom boundary, main contact relationship, mineral layer and fossil layer.

(2) The thickness requirements of the surveying and mapping unit of the measured profile.

In order to fully reflect the basic characteristics of regional structural framework, stratigraphic mapping units should be further divided on the basis of the accuracy of1∶ 200,000 regional investigation and study, and the thickness should be avoided as much as possible. General requirements are as follows:

1) sedimentary rocks are divided into sections on the basis of lithostratigraphic units, and the strata with important sedimentary minerals should be further divided and mapped;

2) Shallow metamorphic rock series can be further divided into lithologic sections according to lithologic combination on the basis of groups and groups;

3) The continental volcanic strata should be divided into eruptive (sedimentary) rock segments according to subcycle and eruptive rhythm on the basis of eruptive cycle (group) and volcanic structure. At the same time, according to the requirements of "double mapping method", the basic types and characteristics of eruption center and volcanic structure should be reflected, and the lithology and its distribution range of metamorphic or shallow metamorphic volcanic rocks should be displayed by patterns on the basis of stratigraphic mapping sheet. However, for metamorphic volcanic rocks with large thickness, wide distribution and clear rhythm, maps can be further divided according to eruption rhythm or rock combination;

4) Quaternary loose accumulation layers should be divided into genetic types and their relative ages, and stratigraphic units are generally divided into series.

(3) Requirements for measured profile of intrusive rock mass

Intrusive rocks (including subvolcanic rocks) should be selected from major rock masses with large scale, complex lithology, multi-stage diagenesis or close relationship with mineralization, as well as measured lithofacies profiles of representative rock masses in different stages, and other types of rock masses should also be controlled by routes or rough survey profiles. For various profiles, various representative control samples should be collected systematically. Intrusive rocks should be divided into maturity and age, facies belt (characterized by structure, mineral composition, chemical composition, etc. ) should be divided in detail according to the rock structure, mineral composition or other characteristics. We can also learn from the mapping method of super-elements, and start with a series of signs such as contact relationship, age, composition and structure in rock mass, and divide magmatic structural units for geological mapping. Subvolcanic rocks should be divided into eruption cycle or subcycle. We should study the main dikes and dikes related to mineralization and divide the intrusion age.

(4) Requirements for the measured profile of metamorphic rocks

Metamorphic rocks should be clear about their genetic types. Various metamorphic rocks should also carry out the following work on the basis of the relevant provisions of the technical requirements:

The shallow metamorphic rocks in the 1) area should be studied by profile to find out their rock types, sedimentary cycles and structural characteristics, marker beds, contact relationships and possible paleontological (including micro-plant) fossils, collect paleomagnetic and isotopic dating samples when necessary, and establish stratigraphic sequences and determine geological ages through the study and synthesis of small structures.

2) The metamorphic types of contact metamorphic rocks should be determined according to the degree of contact metamorphism, metamorphic mineral composition and their combination characteristics, and the metamorphic facies zones should be divided in detail. At the same time, the contact metamorphic characteristics of different periods, different rock types and different surrounding rocks and their relationship with mineralization should be investigated. Paying attention to the study of contact metamorphic halo can be used as a sign of concealed rock mass to be detected.

3) Dynamic metamorphic rocks are divided into metamorphic zones according to metamorphic rock types and metamorphic degrees, and their distribution and influence range are defined. It is necessary to study the main metamorphic zones in detail and make large-scale profiles, and collect various specimens and samples at the same time.

4) According to the degree of migmatization, deploy control survey profile to study migmatization. On the basis of rough division of1∶ 200,000 regional adjustment, according to the degree of migmatization and rock types, the mixed rock zones including mixed granite, mixed rock and mixed metamorphic rock are further divided, and the contact relationship, rock assemblage, structural characteristics, distribution and change law of each rock zone, as well as the age and period of mixed metamorphism are investigated, so as to restore the original rock as much as possible and find out its age and horizon.

3. Selection of section position

1) profile position should be selected in the profile with complete stratigraphic sequence and representative formation thickness.

2) The section line should be basically perpendicular to the stratum strike, and the included angle between the section line and the stratum strike is generally not less than 60.

3) Strata sections with gentle rock occurrence should be arranged on steep slopes (cliffs).

4) If the profile line is covered by residual soil and cannot be measured along the original direction line, when translation is needed, pay attention to finding splicing marks. It is best for all profiles before and after translation to pass through the measurement mark layer to avoid artificially increasing or decreasing the stratum thickness. When the translation distance is greater than 500m, it should be treated as two sections.

4. Procedures and methods for measuring profiles

1) On the basis of reconnaissance, select the specific location of the profile, and the end point of the profile should be selected in the oldest stratum in the survey area, with the lowest outcrop, and go up the mountain along the direction of stratum inclination for survey. Draw the end point of the section on the topographic map of 1∶25000 and get the coordinates of the end point. In the survey, the elevation of the end point can be counted as zero meters, and other numbers on the conductor are 1, 2, 3, ...

2) Using semi-instrumental method to measure topographic profile. The compass is used to measure the orientation of the conductor and the inclination angle of the terrain, and the length of the conductor is measured with a tape measure or measuring rope. Details are as follows:

Setting of traverse points: traverse points should be set in each section with obvious change of ground slope and numbered in the order of measurement direction. When filling in the field survey geological profile record form, the traverse number column should be filled in continuously according to the dot numbers of two adjacent traverse points during the survey, such as 0 ~ 1, 1 ~ 2, 2 ~ 3, ..., and one traversal cannot be written.

Azimuth of the conductor, which is taken as the azimuth of the conductor according to the measured direction of advance.

The length of the conductor requires the tape measure or measuring rope to be straightened and parallel to the ground, and the former measuring hand should read at the moment when the tape measure or measuring rope is straightened.

Angle of inclination, measured at the same time by both hands, is generally averaged. It should be pointed out that the slope angle of uphill is marked with "+"and the slope angle of downhill is marked with "-"to distinguish uphill from downhill and accurately draw the topographic line of this section.

Observe, stratify, measure (measure the exposed position and delamination thickness of the layer on the wire, etc.). ), according to the accuracy requirements, hand-shaped specimens, representative display specimens and fossil specimens used to connect drawings are recorded and collected from the starting point of the traverse along the forward direction. Except for hand specimens, all other specimens or samples need to be numbered and registered on site. At the same time, 1 ~ 2 representative rock strata should be measured on each section of conductor, and the measurement near the contact surface should not be omitted. The position and data of its appearance on the conductor shall be recorded.

3) At the same time of obtaining the above information and data, the site profile shall be made. The specific method is as follows:

According to the slope angle and oblique distance of the traverse, the topographic profile of the traverse is drawn with a smooth curve according to the actual terrain 1∶2000, and the traverse orientation, oblique distance and slope angle are marked above the starting point of each traverse.

Draw a geological map according to the number, location, occurrence and lithology of the layer, and mark the number and stratigraphic code of the layer.

The occurrence position and data of rock strata are marked below the profile, and the numbers and positions of various specimens or samples are marked above the profile. Drawing field profile is convenient for horizon correlation and structural analysis, and it is also an important reference for drawing geological profile map indoors.

5. Indoor layout of survey profile

After the field work, go to work indoors. Indoor finishing work is as follows:

1) sort out and calculate all kinds of data;

2) Register the collected specimens and samples, save them or fill in a form and send them to the laboratory for identification;

3) according to the indoor analysis and appraisal results, modify and supplement the field data;

4) Prepare the traverse plan, measured section and histogram as required.

6. Drawing method of traverse plan

1) On centimeter paper, the direction to the left or right of the horizontal line represents the average orientation of each conductor or the direction perpendicular to the stratum strike, which is taken as the orientation of the profile projection datum line.

2) Pay attention to the layout of the traverse plane on the drawing and consider the reasonable projection of the section. If the direction of command is close to east and west, the horizontal line on the map is west to left and east to right; If it is close to the north and south, the horizontal line on the map is south to the left and north to the right; If the direction of command is northwest or southeast, northwest to the left and southeast to the right; If it is northeast or southwest, it is right to the northeast and left to the southwest.

3) According to the actual traverse orientation and traverse horizontal distance of each traverse point, draw the traverse plan in the upper half of the centimeter paper according to the scale.

4) According to the main geological boundary of each traverse point and the occurrence of representative strata, spread out on the traverse plan according to its horizontal distance.

7. Compilation of measured profile

1) On the lower part of centimeter paper with traverse plan, vertically project traverse points on traverse plan onto the section datum line, take the datum line as the "zero point" for calculating elevation, and draw topographic contour lines according to the accumulated height difference of traverse sections. Please refer to the site profile when sketching.

2) Similarly, the lithologic stratification line, geological boundary and occurrence position on the traverse plan are vertically projected on the section to supplement and improve the geological elements. Note: When the inclination between the direction of the profile line and the strike of the strata is ≤ 30, the dip angle of the rock grain on the profile should be drawn according to the apparent dip angle.

3) Further decorate the outline according to the relevant schematic diagram.

8. Drawing of histogram

1) The formula H = L (sin α cos β sin γ cos α sin β) is used to calculate the thickness of rock strata (i.e. layered thickness) controlled by each single measurement, and "+"is used when the dip angle of rock strata is opposite to the slope direction of traverse ground, and "-"is used when the dip angle is the same as the slope direction, which must be greatly reduced, that is, the absolute value is taken and then calculated. There are two issues to be noted here:

① For some reasons (because the transverse direction is the same as the slope direction, and β > α, or because the transverse direction is the general direction of the section), the thickness of some rock strata is repeatedly calculated, and this part of "negative thickness" should be deducted.

② In the process of profile measurement, if the stratum is reversed locally (not on the two wings of the fold), the absolute value of stratum thickness can be taken each time, but it is still required to distinguish between "positive" and "negative" thicknesses when calculating the cumulative thickness.

2) According to the scale requirements, draw the histogram. note:

(1) The contents of the histogram and the profile must match;

(2) important seams, fossil beds and marker beds. Can be appropriately enlarged;

③ Lithology description should be concise;

(4) The full name of fossils should be formally identified; The order is animal first, plant first, standard fossil first, general fossil first;

⑤ Correctly express the contact relationship of each layer;

⑥ Decorate according to schematic illustrations.

Second, geological mapping.

1.

1∶ 50,000 regional geological mapping is a basic geological work. Its purpose and task is to find out the characteristics of geological bodies such as strata, rocks (sedimentary rocks, magmatic rocks, metamorphic rocks) and structures in the area by filling in the1∶ 50,000 geological map, and to study the basic geological problems such as their attributes, formation environment and development history, so as to provide basic geological data for mineral survey, hydrology, engineering, environmental geological exploration, geological research and geological teaching.

2. Requirements

1) In the study of structure in geological survey, we should pay attention to collecting practical data that can explain specific structural characteristics and try to avoid being bound by various academic viewpoints. The actual data collected on the spot mainly include:

① Various structural elements, including the scale, shape, occurrence and relevant statistical measurement data of various structures (folds, faults, cleavage, joints, cracks, etc.). );

(2) data showing the active sequence, mutual relationship, formation age and evolution process of folds and faults at all levels;

(3) The relationship between the actual ore-controlling data of structures such as folds, faults, fractured zones, compressional zones, fractured zones and unconformities and mineralization;

(4) Typical, complete, representative and controllable structural elements at all levels should be selected, and detailed large-scale profile studies or structural observation points should be arranged selectively for systematic measurement and statistics.

2) There is no systematic survey of Quaternary geology and geomorphology, but it was learned by the way in geological mapping and mineral survey. The specific requirements are as follows:

① The representative profile of Quaternary geological development area should be measured according to different genetic types, and the stratigraphic age should be determined by using microfossils, fossils, isotopes 14C and other data, and the stratigraphic structure, composition and morphological characteristics should be studied to determine its genetic types and understand its ore-bearing nature.

② Based on the field investigation and the interpretation data of aerial photographs, we collected the micro-geomorphological features such as river valleys, terraces, ancient planation planes, ancient glaciers and karst. And while observing and describing, draw a plain map and take pictures.

③ Special interlayer in Quaternary geological body (such as biological layer, paleosol layer, geochemical anomaly layer, magnetic anomaly layer, weathering layer, ore-bearing layer, gravel layer, ancient culture layer, etc.). ) Detailed investigation and research should be conducted and necessary test samples should be collected.

3) The calibration and error range of various geological bodies in field mapping should meet the technical requirements.

4) Geological observation route adopts the layout principle of combining crossing method with tracing method and combining general route with main line. The specific application in the field should depend on the complexity of geological structure. In simple areas, the crossing method is the main method, and in complex areas, important geological bodies, key geological boundaries, contact zones, mineralized alteration zones, ore-bearing beds and other prospecting indicators are appropriately tracked along the strike. The main route should be arranged in the area with strong control, good bedrock outcrop and convenient traffic conditions. In addition to detailed observation records, relevant samples should be collected systematically, and large-scale route profiles should be drawn on the main routes.

The survey route spacing is generally 500~800 m, and the main route spacing should not be greater than 2.5km. The layout of the survey route should be appropriately diluted or encrypted according to factors such as the complexity of geology and mineral resources in the survey area, the exposure of bedrock, natural and geographical conditions and the obvious degree of interpretation marks of aerial photographs. In areas where geological and mineral conditions are not very complicated or traffic conditions are difficult, it can be diluted appropriately, but the general route should not be greater than1000 m; Quaternary distribution area can also be appropriately diluted.

5) The requirements for observation and recording of geological observation points are as follows:

All kinds of geological boundaries, geological bodies and other important geological, geomorphological and hydrogeological phenomena should be observed and recorded at fixed points; In areas with relatively simple lithology, the maximum spacing of lithologic control points should not be greater than 500m, and there are 3 ~ 4 observation points per square kilometer.

Continuous observation records must be made along the geological observation route. Route profiles should be attached to complex geological structures, and important geological phenomena must be sketched or photographed.

There are three ways to calibrate the position of observation point (fixed point):

Using the 65,438+0 ∶ 25,000 terrain, features and landforms, the actual positions of geological observation points are directly marked on the map by visual inspection.

The surveyor stands on the observation point and uses a compass to measure the positions of known control points (peaks, highlands, villages, bridges, road intersections, etc.). ) meet on the topographic map, and the intersection point is the position of the observation point on the topographic map. Note: Try to use more than two known points to intersect, and the included angle formed by the intersection of two points should not be less than 30, preferably around 45.

GPS fixed-point method directly marks the value of rectangular coordinates (x, y) on topographic map with hand-held GPS instrument.

The record and format requirements of geological observation points are as follows:

The records of observation points should truthfully reflect the objective geological phenomena, and the records must be serious, comprehensive, accurate, focused, clear-cut, concise, neat and consistent. The recorder must work closely with the master surveyor to fully understand the specific position and spatial relationship of the observation point on the geological map, and strive to attach illustrations to the record, including route profile, structural profile, rock (ore) sketch, fossil sketch, landform observation and necessary photos to supplement the description of the text.

Unified format of field original records for geological mapping (for example);

Comprehensive training course of geological exploration

Description of record format:

The date, place and weather conditions should be recorded at the beginning of each day, where the place records the workstation or drawing area.

Points should be marked by elevation points, villages or other fixed features near the observation point. When there is no such sign nearby, the previous observation point can be used as a sign.

The right side of the notebook is recorded in words, and the left side is made of sketches, route sections or attached photos. If necessary, it can also be used for short text notes or supplementary records. After the photographic data are recorded in the corresponding geological observation records, the negative number, photographic object and content, as well as basic data such as photography time, orientation, aperture and speed should be indicated. Where there are routes on the map, there must be written records to confirm each other.

The next day's observation or work summary should start a new page. The record book shall not record anything irrelevant to the field geological survey.

6) The continuous drawing of geological boundaries is the main means and method to form geological maps, which is completed on the basis of completing a certain number of observation routes and observation points in the field. In general, after two or more crossing routes are completed, continuous drawing can be carried out on site according to the observation points with the same sharpness and structural parts in adjacent routes, combined with field exposure. If it is a tracing route, the observation points pointing to the same front and back can be drawn continuously on site. In order to ensure the quality of drawings, the following points need to be emphasized:

Hua Lian must be carried out in the wild, and can't be sketched by memories indoors.

The same points, but distributed in different structural parts (such as the two wings of anticline) can not be drawn together.

The points are the same, but the occurrence is obviously different and the extension direction is also different. If it is staggered by faults, it cannot be drawn directly.

Don't use observation points as inflection points to draw polylines. The relationship between rock formations (or fault occurrences, contact occurrences, etc.) should be fully considered. ) and terrain, and use V-shaped rules for reasonable continuous drawing.

In the evening, summarize and sort out the materials of the day (including records, hand-drawn, specimens, etc.). ) as a necessary supplement and modification. If major mistakes are found, they should be re-investigated on the spot the next day and corrected.