Paleontological Techniques

This brief description of paleontological techniques will enhance reader's knowledge about fossil collection, tools, excavation, identification and techniques to study fossils.

1. Paleontological Techniques By Fizza Ali (1029) Group 7 BS ZOOLOGY 7 th M

2. Paleontology  is the study of the history of life on Earth as based on fossils.  Fossils are the remains of living things that have been replaced by rock material or impressions of organisms preserved in rock . The documented form of paleontology appeared from 5 th century. After George Cuvier‘s work on comparative anatomy, paleontology became popular during 18 th and 19 th century. There are many different ways of collecting fossils and each is adapted to a particular situation.  Modern paleontologists have a variety of tools that help them discover, examine, and describe fossils. Literature

3. How to find Location of Fossils?   Fossils  are mostly found where  sedimentary rocks of the right age are exposed (Clastic rocks). Fossils are also found in non-clastic rocks. R iver valleys, cliffs and hillsides, and human-made exposures such as quarries and road cuttings . By chance Fossilized teeth can often be found in or near river bed banks, sand pits, and beaches. Knowing about the habitat of respective organism (Gobi desert) Preservation current fossil's preserved state . Exposure

4. T wo different fossil collection methods are typically employed: ( 1) Bulk collection of stratigraphically in-place fossil-containing sediment or rock . ( 2) Surface collection of loose, individual fossils that have weathered out of an outcrop . Should have Good Data : GPS coordinates Digital photographs of both the specimen and the site Field notes about stratigraphic placement Taphonomic information Collection Method

5. Dry Sieving Utilizes screens of progressively smaller mesh size to sieve out the smallest specimen. Method is useful for the smallest fossils (such as tiny teeth in very loose, sandy sediment). Can be used to find fragments of bone.

6. Screen Washing Underwater screen washing of fossil. Used for specimens too hard and tightly-packed for dry sieving. After all matrix passed through screen, fossil is air-dried. Dried concentrate can then be bagged and shipped back.

7. Surface Collecting Specimens that can be collected without digging A hole larger than one meter square Float fragments found on surface of outcrops Determine the highest level of the bone Simply wrapped in toilet paper, labeled and bagged For larger specimens, field jackets are used.

8. Tools Brushes Steel Points Magnifying Glasses Rock Chisel Picks and Shovels Hand Lenses Pneumatic Air Scribe Paleo Bond Tile Nippers Tools which used for / separation / in finding out of fossils Rock Hammers Jackhammers Full-Sized Pick Hammer Sledge Hammer and Pry Bar Probes Gloves Goggle Diamond Saw

9. https://www.slideshare.net/pramodgpramod/techniques-in-paleontology http :// preparation.paleo.amnh.org/35/techniques-in-the-field https:// en.wikipedia.org/wiki/Fossil_collecting https:// doi.org/10.1111/j.2151-6952.1985.tb01686.x https:// link.springer.com/chapter/10.1007/978-94-017-0581-3_1 References

10. Excavation technique BY Mahnoor Fazal (1008)

11. Excavation For paleontologists, excavating a fossil is a slow, careful process. Although an excavation team can use large tools and cranes to remove an entire skeleton in one large slab, removing the bones from the surrounding rock takes time and patience. For this reason, when working with large skeletons or bones, paleontologists often remove large specimens, encase them in plaster and ship them to a research facility for easier study.

12. Steps Working from the exposed bone surfaces to the unexposed surfaces, paleontologists slowly flake away the rock  matrix  that surrounds the bone . This may sound difficult, but there's a  plane of weakness  between the bone and the rock. The rock will tend to break along this plane with the help of tools, like paintbrushes and dental picks. Paleontologists can also mist the rock with water to soften the sediment .

13. For brittle bones Sometimes, the fossilized bone is brittle, so brittle that the removal process could cause it to shatter or break. When this happens, researchers will reinforce the bone with a thin glue or resin. This liquid soaks into the bone, reinforcing its structure. This step requires lots of care, since the glue can permanently attach flakes of sediment or dust to the bone.

14. Age determination Once the fossil is removed from the rock, scientists can determine its age using a  mass spectrometer , measuring isotopes for radiometric dating. Another technique is to compare the fossil to other samples with known ages. Other tools include computerized tomography (CAT) scans and computer models. When it comes to vertebrate animals, paleontologists can also approach the skeleton like a giant jigsaw puzzle, trying to figure out exactly how the bones fit together to determine how the animal lived and moved .

15. Identification and excavation Asra Mehfooz 1022

16. Identification of Fossils: One of the common problem paleontologists face Simple process of observation and comparison that allows us to figure out what part of the animal we have Paleontologists collect as many as possible fossils from a rock or sediment Now the question is how do paleontologists tell what part of the animal it is?

17. What part of the animal it is? Teeth Claw Meat-eating dinosaur Enamel covering Sharp edges Seratted Made of bone Spongy texture Grooves Keratin sheath

18. Identification: We can also identify the kind of the dinosaur from the fossils. Example: These two fossils teeth represent two fossil teeth represent two different meat eating dinosaurs. Obviously quite different in shape, but there are also many other features. Under microscope, we can look out serations and edges of these teeth both have different shape, proportion amd curvature.

19. Plant Eating Dinosaurs: NODOSAUR Triangular teeth Large points Useful for chomping plant material PLEUROCOELUS Blunt teeth Useful for stripping leaves off of tress and other larger plants

20. Techniques of Fossils Study By: Ayesha Tabassum 1014

21. Fossils Preparation Fossil preparation is the act of preparing fossil specimens for use in paleontological research or for exhibition, and involves removing the surrounding rocky matrix and cleaning the fossil. Techniques Acid maceration technique Film pull or peel technique Transfer technique 22

22. Acid maceration Acid maceration is a technique to extract organic microfossils from a surrounding rock matrix using acid. Hydrochloric acid or acetic acid may be used to extract phosphatic fossils, such as the small shelly fossils, from a carbonate matrix. Hydrofluoric acid is also used in acid macerations to extract organic fossils from silicate rocks. 23

23. Cont... Fossiliferous rock may be immersed directly into the acid. Or a cellulose nitrate film may be applied (dissolved in amyl acetate). Which adheres to the organic component and allows the rock to be dissolved around it 24

24. Transfer T echnique The transfer technique is a technique to stabilise and prepare fossils by partially embedding them in plastic resins (i.e. epoxy or polyester) in order to preserve the position of the preserved fossil once all of the rock matrix is subsequently removed. The technique is notable for delivering exquisite preparations of both very high scientific and display value. This allows the potential to preserve microscopic details on the surface of the fossil. 25

25. Cont … The face of the specimen adjoining the rock surface with two coats of peel solution When the film is dried the portion of the rock having fossils materials is removed. The specimen is then immersed in 25% HF to dissolve away the rock matrix. Finally, the specimen is washed, dehydrated and mounted. 26

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27. Film or Peel Technique Most suitable for perifiactions . First step involves etching of the fossils surfaces with the help of some mineral acids (e.g., HF or HCl ). After etching the specimen surface is washed with water, dried and covered with nitrocellulose. After drying in air for about 6 hours, the film is carefully peeled and mounted on a slide by canada balsam and can be studied under binocular microscope. 28

28. Microtomy Technique This technique is useful for fossil woods which retain much of the cell wall structure intact The specimen is first softened by treating it with HF and potassium chlorate, followed by a mixture of equal parts of phenol and 95% alcohol. Therefore, it is embedded in paraffin or celloidin and sectioned with the help of a microtome. The sectioned materials are stained and studied. 29

29. X-ray Technique Some fossils are damaged due to acid treatment in the process of peeling or microtomy. Such fossils can be studied by X-rays radiography. Technique is particularly useful for the study of calcified seed obtain from coal balls. The specimen is photographed by X-rays and difference in density are recorded by noting corresponding differences in shadow effects. 30