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Fossilization and Fossils. So what exactly is a fossil? ANY evidence of ancient life. Body fossil teeth or bones Trace fossil cast, track, burrow.

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Presentation on theme: "Fossilization and Fossils. So what exactly is a fossil? ANY evidence of ancient life. Body fossil teeth or bones Trace fossil cast, track, burrow."— Presentation transcript:

1 Fossilization and Fossils

2 So what exactly is a fossil? ANY evidence of ancient life. Body fossil teeth or bones Trace fossil cast, track, burrow

3 What is a scientist who studies fossils called? paleontologists Archaeologists study the remains of ancient humans and their cultures. Write this down; it is an IMPORTANT distinction! Next question…

4 Fossils If the layers of sedimentary rock are the pages that tell the story of the Earth, fossils are the words. Literally, the word fossil means “ dug up ”. Technically speaking fossils are remains of life that are at least 15,000 years old. Preservation can include both altered and unaltered hard and soft parts. Fossils can also be casts and molds. Found in shales, sandstones, limestones, amber, ash, nodules, tar, and ice. The study of an organism from death to fossilization is called taphonomy (can include post-fossilization events as well).

5 Process of fossilization

6 Fossilization depends on two critical steps: rapid burial by sediment mineralization Helpful conditions: anoxia (lack of oxygen following burial) minimal disturbance subsequently mineral-rich water in sediment

7 Types of Fossilization Unaltered Remains Original material, including soft parts preserved Rapid burial in ice, tar, or mummification Recrystallization Original material dissolved New mineral deposited simultaneously Permineralization Minerals infill pores and holes Molds and casts Infilling with other material Often, sedimentary infill Carbonization Preservation as thin films of carbon Outline and sometimes detailed structures preserved

8 Unaltered Soft Parts (Amber) Scorpion Mosquito Feather

9 Unaltered Soft Parts (Ice) “Blue Babe” bison Siberian Wooly Mammoth

10 Unaltered Hard Parts: Tar and Anoxic Silt Beetle in tar LaBrea Tar Pit Fish from Messel, Germany Avitelmessus, NC

11 Unaltered Hard Parts (skeletal) Smilodon Columbian Mammoth Ashfall Park

12 Recrystallization: Aragonite to Calcite Pterorhytis conradiBusycon carica Chesapecten jeffersonius Pliocene Cretaceous Eocene Athleta petrosus Polinices sp Urosalpinx sp.

13 Recrystallization: Change in Crystal Structure Mississippian Crinoids Dalmanites Cyclonema Euproops Edrioasteroid

14 Carbonization Knightia Dragonfly larva OpabiniaCanadia Spider

15 Carbonization Sphenopteris

16 Permineralization Jurassic Pinecone Permineralized Dinosaur Bone: Cell Structure Preserved Petrified Wood Brazil Dinosaur Bone Shark Teeth

17 Altered Hard Parts (replacement) Pyritization Silicified Mollusks Silicified Stromatolite

18 Molds and Casts shell shell dissolvessediment infilling external mold cast shell Sediment fills void shell interior Shell dissolves steinkern

19 Casts and Steinkerns

20 Trace Fossils Reflect the activity, or behavior, of organisms on land and in marine settings. Exogenic – on the surface. Endogenic – within the substrate. Shape of the trace fossil does not always mirror the animal. Trace fossils are named for their particular shape and form and not for the animal that made the trace.

21 Same animal may make several different types of trace fossils.

22 Trilobite resting trace

23 Trilobite trackway

24 Grazing trace

25 Other trace fossils include trackways on land (mostly dinosaur, reptile, and amphibian) and coprolites (fossilized feces, “ poop ” ).

26 Glen Rose, TX Dinosaur Ridge, CO

27 Coprolites Turtle Mammal Dinosaur Crocodile

28 Factors that Affect Fossilization


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