Preface
Nearly all fossils collected in the field are wrapped or filled with surrounding rocks and must be organized before research can be carried out. The first step is to repair and expose the fossils from the enclosing rocks, so that the specimens can be easily observed and studied; the second step is to assign labels to the fossils with numbers and indicate their origins and stratigraphic positions, so that the specimens can have complete scientific research value. In the process of finishing, the most difficult, complicated and technical step is the repair of fossils. Repairing refers to removing the surrounding rock that wraps or fills the fossil without damaging the fossil, so as to expose the important structure and structure of the fossil. Although the second step is not technically difficult, it is very important. If a carefully repaired fossil is missing the necessary information, it will greatly reduce its scientific value and cause a great waste of specimen resources and field work. In order to guide and standardize the repair work of vertebrate fossil specimens, and to lay a good foundation for further indoor research, we have formulated this procedure as a guiding standard for the finishing work of vertebrate fossils.
This regulation is proposed by the National Science and Technology Infrastructure Platform.
This regulation is drafted by the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences.
Drafted by Liu Liping,Ding Jinzhao.
This regulation is interpreted by the National Platform for Specimen Resources***.
1 Scope
This specification defines the contents, tools, steps, methods, and precautions for the repair of vertebrate fossil specimens.
This specification applies to the repair and preservation of vertebrate fossil specimens.
2 Normative references
The provisions of the following documents become the provisions of this procedure by reference. All subsequent revisions (excluding errata) or amendments to dated references do not apply to these Regulations, however, parties to agreements under these Regulations are encouraged to investigate the possibility of using the most recent versions of these documents. Where a document is cited without date, the most recent version applies to these Regulations.
Natural Science and Technology Resources*** Descriptive Specification for the Classification and Coding of Vertebrate Fossil Specimen Resources.2006
3 Terms and Definitions
3.1 Vertebrate fossil
Vertebrate fossil is the petrified remains (or remains of a vertebrate) of a vertebrate animal including early chordates and vertebrates.
Vertebrate fossils are the petrified remains of vertebrates, including early chordates and vertebrates, including anurans, fish, amphibians, reptiles, birds, and mammals, as well as fossilized entities, fossilized remains (e.g., fossilized eggs, fossilized feces) and fossilized remains (e.g., fossilized footprints), etc.
3.
3.2 Arrangement of specimens
Cleaning, repairing, reinforcing, numbering, registering and archiving the vertebrate fossil specimens obtained, as well as collecting and archiving the images and information related to the specimens.
4 vertebrate fossil finishing
4.1 Preparation before finishing
4.1.1 Repair tools and major equipment
Solid microscope, magnifying glass, pick needle, hammer, burin, electromagnetic engraving machine, pen-type pneumatic engraving pen, sandblasting machine, air compressor, grinding tools, plastic dropper, ear washing ball, small brush, tweezers and so on. In addition, according to the actual needs of the work, can also make some suitable for personal use tools.
4.1.2 specimen reinforcement, adhesive raw materials and configuration methods
The specimen reinforcement of raw materials more commonly used are acetone, nitro varnish and polyvinyl butyral, mainly used to configure specimens reinforced with dilute glue. Thin glue for nitro varnish or polyvinyl butyral to acetone solution, the concentration is generally 30% to 40%, in practice, depending on the status of the specimen can be adjusted to the amount of solvent and solution to change the concentration of thin glue. Acetone and nitrocellulose varnish for daily chemical supplies, flammable and explosive, the preparation of a good thin glue should be careful to avoid high temperature and sunlight.
Specimen bonding glue including unsaturated polyester resin, AB glue (epoxy resin) and 502 glue (cyanoacrylate) and so on.
4.1.3 Repair personnel protective equipment
Goggles, dust (toxic) masks, earplugs and gloves, etc..
4.1.4 Specimen holding materials
Plastic boxes, plastic (or cardboard) trays, brocade boxes and photo albums used for the preservation of specimen image information, CD-ROM packages (boxes) and so on.
4.1.5 Repair room working environment requirements
Repair of specimens should have enough space and the corresponding work platform, chairs (stools), etc., the specimens will be unfolded in the process of repairs will produce a large number of fine dust, the preparation of reinforcing agents, adhesive materials with volatile and corrosive, repair personnel and instruments (such as microscopes) are harmful, so the repair room should be Installation of good ventilation, dust removal equipment, repair personnel can wear dust (toxic) masks.
4.2 Repair procedures and steps for non-microscopic vertebrate fossils
4.2.1 Preparation of field data
When dealing with specimens collected from the field, first of all, we should check whether there are corresponding field collection records and photographs, especially when dealing with the set of boxes and gypsum packages is even more important so that we can understand the distribution of specimens in the set of boxes or gypsum packages to do. The first step is to take a look at the specimens in the box or plaster bag and to get a clear picture.
4.2.2 Exposure of fossils
Exposure of fossils in simple packages is relatively simple, as long as attention is paid to recording the specimen number and related information on the outside of the package before opening the package. Gypsum packages and boxes are more complicated and have a few precautions.
To open a plaster bag, you should start with the head of the bandage, which is usually exposed at the top, and find it. When you find it, wet the plaster with water to soften it, and the bandage will be easy to open. Sometimes, the plaster bag is made very smooth, the plaster layer is very thick, can not see the head of the bandage, in this case, you can rely on the shape of the plaster bag to see the order of the bandage winding, the outside of the plaster bag soaked with water, use tools to chisel off the surface of the plaster to reveal the bandage, and then use scissors or saws to carefully remove the bandage. To be on the safe side, it is best not to use a hammer and burin to strike.
4.2.3 Reinforcement of the specimen
After opening the plaster bag, if the specimen was collected from a soft surrounding rock, the specimen should be reinforced. The specimen should be cleaned up as much as possible, and then use a plastic dropper to carefully drip thin glue into the specimen gap. First of all, the concentration of about 10% of the thin glue will be completely soaked throughout the specimen, and then the concentration of about 30% to 40% of the thin glue repeatedly poured a few times, until the specimen can not penetrate the thin glue until.
4.2.4 Specimen repair
4.2.4.1 Repair of three-dimensional fossils
4.2.4.1.1 Repair of large fossils
Some of the large vertebrate skeletons (e.g., limb bones, vertebrae), is usually still the traditional method of mechanical repair, the use of hammer and burin. Should be equipped with several different types of hammers and burins to cope with a variety of lithology and different sizes of specimens.
In the hammer and burin repair specimens before, it is important to fix the specimen. Comparison of solid and large specimens can be directly with sandbags to stabilize the pad, but also in the specimen under the soft rubber cushion or the specimen will be placed directly in the sandbox repair, in order to reduce the vibration of the specimen. Generally take the first to thin, after repairing the method of exposure, in the fossil is not exposed before, should be uncovered layer by layer until the fossil exposed, or from the least part of the surrounding rock, little by little to remove the surrounding rock. The burin should be sharpened to reduce the vibration of the specimen, when the burin is very close to the fossil, it is not appropriate to sharpen it too much, so it is easy to hurt the fossil. Repair process, the direction and strength of the hammer hit the burin is also very critical, can not be greedy, trying to fast, maintain patience and careful is very important.
In the repair process, if the specimen is accidentally broken, it is necessary to repair in a timely manner. In bonding the specimen should be based on the specimen's condition. The stubble is more neat, the specimen is stronger, you can first repair the pieces and then bonded back, on the contrary, it should be bonded first, reinforced and then repaired. In bonding the choice of adhesive depends on the size and quality of the specimen fragmentation of different, if the specimen fragmentation is very light, very small, seam fit is good, it is best to use nitro varnish or 502 glue. If the pieces of large, heavy specimens, in the adhesive surface is required to use a different adhesive, the general use of unsaturated polyester resin or AB glue, just pay attention to the amount of the use of the appropriate, because once the glue is hardened, it is difficult to deal with the chemical method again.
In the repair of three-dimensional specimens, after repairing one side, need to clean up the reinforcement, turn over on a thick foam rubber mat and then repair the other side. Repair of the skull is more demanding than other parts, and it is very important to protect the repaired side before repairing the other side. The repaired side can be protected with a plaster cast or a backing of polyethylene glycol 4000 (soluble wax). Soluble wax in warm water (about 40 ℃ or so) can be dissolved, after the repair is completed, it is easy to remove.
4.2.4.1.2 Stereoscopic repair of small fossils
The repair of small, complex specimens in stereoscopic form (especially skulls) is usually carried out under a binocular solid microscope. Should first understand the specimen of some basic anatomical knowledge, find some relevant picture information. The best choice for a microscope is to use a sliding bar with a long arm, so that the operating range will be larger.
Repairing these fossils requires the use of small repair tools. If the surrounding rock is hard, small tools are generally more limited, and an electromagnetic carving machine can be used. This machine's impact frequency of about 50 to 60Hz; impact times of about 60 to 120 times per second, the impact frequency can be adjusted to adapt to the different hardness of the rock. Need to pay attention to is not too much force, otherwise the specimen will leave the surface of the needle point hit marks. Repair down the rock debris and debris can be used rubber blowing ball blowing off.
The skull is treated in the same way as a single bone, but it is generally more difficult and more demanding, so it should be more careful. First of all, one side of the specimen should be exposed to the outline, and then the need to hollow out places such as eye holes, temporal holes and so on a little bit of hollowing out of the periosteum. When repairing a fossil whose internal structure is not common or which has been deformed during burial, we should be more careful and reinforce the newly repaired part while repairing. In the case of complex repairs, a curved needle should be used to expose as much of the skull's internal structure as possible. If a small piece of fossil is accidentally removed, even if it is very small, it should be immediately glued back into place under the microscope. The repair table should be kept as clean as possible to make it easier to find the broken fossil.
4.2.3 Repair of slab fossils
Slab fossils are mostly marine or lake or river deposits, and are usually composed of fish, aquatic reptiles, and birds. The skeletal parts of these fossils are almost always flattened, and even the soft tissues, skin and its derivatives are preserved. Repairing these fossils is not only technically demanding, but also requires very delicate tools. Usually in the market can buy like a pen like a round clip (electronic instruments and clock repair with a hand twist) and dental nerve needle handle with different sizes of ordinary sewing needles is a fine pick needle, the tip of the needle can be polished with oil stone; another kind of needle is bought back from abroad by a number of different types of high-carbon steel made of them can be mounted directly on the card head, but the grinding of the need for special diamond grinding wheels. A variety of fine dental spatulas are available from medical equipment stores, which can also be used as flossing needles. Some technicians can make their own small tools for fossil repair work in different lithologies.
If the fossil is broken into many pieces, the first thing to repair is to splice the fossil, if there is a field photo and has a number, the splicing work will be relatively simple, but if there is no such reference, we can only according to the bone joints, color, thickness, and the natural seams of the slabs of the fossil is divided into groups, the broken fossil is put together into a more complete large pieces, with glue for bonding and reinforcing the repairs. More loose specimens can also use plaster to make a bottom bracket or directly set in a wooden box, so that the repair is not only easy to carry, but also not to damage the fossil. In the repair of such fossils must be used in the long arm of the high power optical body microscope, magnification of 6-31 times, you can more clearly see the very small parts. Most of these fossils are from shale, so it is not possible to use tools to pry them directly from the cracks, as this will easily split the fossil into two pieces along the surface, and they should be peeled off one layer at a time according to the stratification. If you are skillful, you can use a fast carving machine to expose the general outline of the specimen, and then use a picking needle to carefully repair the fine parts. Sometimes the boundary between the specimen and the surrounding rock is not very clear or the color is close, then you can use a small brush with a little water (or acetone), so it is easier to distinguish between the fossil and the surrounding rock. Repairing this kind of specimen should be operated by more experienced and skilled technicians in order to ensure that we can get a fine fossil specimen.
Another typical type of plate fossils are those preserved in marine tuffs and shales, which are exceptionally well preserved, but the enclosing rocks are very hard and the nature and color of the fossils and the enclosing rocks tend to be close to each other, which makes repairing them somewhat more difficult. These fossils are so hard that it is almost unnecessary to reinforce them before repair. Repair should start from the exposed bones or better repair place, can not be taken for granted blind operation, otherwise it is easy to mistake the fossil for the surrounding rock repair. Hammer, burin can only be used to remove large pieces of surrounding rock, the general outline of the specimen exposed, the specimen near the small tools to be used under the microscope to repair.
In recent years there is a better repair tool, that is, pen-type pneumatic engraving pen, it is powered by air compressor, the use of high-frequency impact crushing rock, the vibration of the specimen is very small, but also the specimen can be repaired to a very clean, to achieve the effect of hammering, burin and engraving machine can not reach.
4.2.4 Repair personnel's professional ethics
Repair personnel in the repair process to objectively treat each fossil specimen, absolutely not rely on subjective consciousness to repair or beautify the specimen. In addition, in the repair process may encounter some with the surrounding rock is not the same place, they are likely to be skin or derivatives, etc., these are able to bring information to the scientific research, repair at any time to keep in close contact with the researchers, and never deal with unauthorized or throw away some seemingly useless things.
4.3 Microfossil picking
Microfossils are generally obtained by sieving and washing, generally do not need further repair, only need to pick the fossil from the sand samples can be.
Pick the sample before you need to know the number of sand samples from the field back to the box (bag) and field number, and check with the packing list is consistent.
Field sieve wash good sand samples to pick samples but also screening, with three different sizes of mesh sieve will be divided into sand samples coarse, medium, fine three types. Sieve mesh of the largest in the upper layer, the most dense in the lower layer. Mesh were 10, 20, 35 mesh, sub-selected samples were selected.
Pick sample work must be carried out under a high optical body microscope, magnification 6 ~ 31 times. Coarse and fine sand samples to choose a different magnification, until it is clear to see. In the microscope under a plastic (metal) small plate, in the small plate filled with the right amount of sand samples, the small plate from left to right or from top to bottom to move, carefully identify the fossils. Once a fossil or suspected debris is found, the fossil is carefully clamped with small tweezers and placed in the specimen box. Fossilized bones, broken teeth, and complete teeth are placed in separate small specimen boxes. If there is any sediment or nodule on the surface or crown of the tooth, you can use a small soft brush to clean it under the microscope, and the nodule or other adhesive material can be removed with a small picking needle.
Each small box containing specimens on the lid must be labeled or labeled with the specimen's field number, and remember that fossils from different layers and locations should be placed separately.
4.4 Indoor numbering and labeling
4.4.1 Indoor numbering
In order to facilitate the study of vertebrate fossil specimens and curation, the repaired specimens should be numbered. Numbering rules can be specified according to the specific conditions of each preservation unit. If the specimen is large enough, the number should be labeled on the specimen as far as possible, if the specimen is too small, the number can not be labeled on the specimen, it is necessary to use a suitable container to put the specimen to hold a good, put the number labeled on the container. Number and corresponding specimens should establish a complete archive system, in order to facilitate future checks.
4.4.2 Labeling of specimens
Each incoming specimen should be accompanied by a label. Label content should include at least the following items: number, name, description, collection, location, specimen age, collector and collection date.
4.4.3 specimen classification
By the objective value of the specimen, the degree of rarity and preciousness of the fossil specimens are divided into different levels, to facilitate the management. Vertebrate fossils can be generally divided into three levels: ① type specimens, indicated by two red dots; ② subtype specimens or specimens used for plates, illustrations, specimens in the specimens indicated by a red dot; ③ other specimens are categorized as specimens in the specimens without special signs.
4.4.4 Recorded into the computer
Currently have the conditions of the specimen preservation unit, the specimen data and images should be recorded into the computer.
4.5 specimen photography
As far as possible, each specimen for photography, typical specimens should be photographed from multiple angles or details, with a scale, in order to understand the actual size of the specimen. Background generally choose a piece of contrast with the color of the specimen and the good flat velvet, if necessary, to assist some padding, so that the specimen to achieve a suitable position and angle. Each photo should be numbered according to the specimen number, so as to make the photo and the real thing consistent and convenient for reference. Specimen photos should be a separate file.
4.6 field information clear drawing, organization
Field excavation log, layout plan, stratigraphic section, excavation prospecting maps and other pencil sketched drawings, indoor need to further clear drawing, and copy backup. Field photo and video information should be organized one by one, and burned into VCD or DVD discs for permanent preservation. Field excavation of all kinds of data and information to be rearranged in the computer and simple statistical verification to see if there is wrong data, and these information will be burned to CD-ROM.
4.7 Packaging, placed in the box
Organized vertebrate specimens can be stored in the box, to avoid the specimens stacked together with each other collision, friction and damage to the specimens. According to the different sizes of specimens, plastic boxes, paper specimen boxes, plastic (cardboard) trays as a container, containers can be used soft paper, cotton and other lining material to ensure that the specimens in the box is relatively stable, the box needs to be accompanied by a specimen label.