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Smithsonian National Museum of Natural History Logo The Department of Paleobiology - The Life of a Vertebrate Fossil
Level 4 - Unraveling the Story - Back to the Matrix
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A scientist picks foraminifera (microscopic, single-celled marine organisms) from a matrix sample. These organisms are used for dating sediments and studying ancient climates and ocean circulation.

Studying the matrix, or sediment, that surrounded the specimen in the ground provides evidence for how the animal lived and where it died:

  • Fossil pollen and leaves tell about ancient vegetation and climate.
  • Invertebrate shells contain chemical signals in their oxygen isotopes that can reveal the water temperature when the animal was alive.
  • Sediments and invertebrate shells can show wether the animal was buried in a lake, stream, ocean, or bog.

Fred Grady, Department of Paleobiology volunteer, sifts through Miocene age marine matrix from Calvert Cliffs, MD. Some of the specimens found include sharks teeth.

Violent End

  • Animals can die from old age or they can be killed by:
  • Disease such as osteoarthritis, infections, tumors.
  • Starvation.
  • Predators.
  • A natural catastrophe, such as a flood.

The way an animal dies may leave marks on the animal's bones or affect how the bones are deposited at a burial site. Here's what you might see:

  • Bone deformed during life (osteoarthritis, infections, tumors).
  • Bone that was thin and weak during life (starvation).
  • Crushing or tooth punctures on bones, missing skeletal parts (predators).
  • Bones of many different animals preserved in one area (a natural catastrophe, such as a drought flood).

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