Rocks, Rossils, etc,..

  1. correlation
    • the method used by geologists to match rock layers of the same age.
    • Matching is based on similarities in the sequencing of layers or unique common fossil species or groups of fossils.
  2. what are responsible for plate techtonics
    convection currents
  3. currents near the bottom of the sea are.... (faster/slower)
  4. Age of earth
    4.6 billion yr old
  5. how many mi in bi
    1000 million
  6. Fossils
    Any evidence of past life, ice age, or older.

    (10,000 BC)
  7. Direct Evidence
    actual remains, may or may not be changed

    usually bones, teeth, or shells, rarely is it soft fleshy parts of the organism
  8. Indirect Evidence
    tracks, traits, burrows (called trace fossils)

    coprolite ( fossil dung )
  9. Conditions Favoring preservation of fossils:
    rapid burial

    presence of hard parts (bone, teeth, shell)
  10. Common Types of Preservation
    • Replacement
    • Carbonization
    • Imprints
  11. Replacement
    original materials are broken down and is replaced by minerals from groundwater occurs at a molecular level.

    original bone/shell is turned to stone.


    The original material is dissolved away by ground water and minerals from the surrounding rock take its place.

    Common replacement minerals: quartz, calcite, rarely hematite.
  12. Carbonization
    - all volatile (blood, fat, etc,..) (REACTIVE)

    - all volatile ( reactive substances, liquids) are squeezed out leaving a thin film of carbon. Commonly preserves plants, fish, rarely others (salamanders, Jellyfish)

    -all fluids (water based, also fats, blood) are squeezed out leaving a thin film of carbon. Commonly preserves leaves, fish, rarely frogs, salamanders, jellyfish.
  13. Imprints
    thin bodied organisms with chitonous (scales,exterior) exoskeletons
  14. Clasts
    - a three-dimensional replica of the organism (usually bone/shell)

    - may be internal (from the inside of a shell, hardened mud) or external
  15. Mold
    surrounds the clasts (like a cake mold)
  16. Rare Types of Preservation
    • - amber: fossilized tree sap
    • - ice: only Ice Age organisms
    • - tar: whole community preserved
  17. Absolute Age
    the age of a fossil rock layer or igneous rock (intrusion/lava flow) in yrs.
  18. Radioactive elements....
    ...break down at a known rate into stable elements (daughter elements) called half lifes
  19. Half Life
    the amount of time it takes for 50% of a radioactive element to break down into a stable element (daughter element)
  20. Cross-cutting
    any layer cut by a fault or intrusions older than the fault or intrusion
  21. unconformity
    gap in the rock record stripped away by erosion
  22. Geologic time is broken up into (equal/unequal) units of time based on....

    ......major events and/or major changes in life forms units from largest to smallest

    Eon -> Era -> Period -> Epoch
  23. origin of earth
    4.6 bya
  24. oldest rocks on Earth
    3.8 bya
  25. Proterozoic Eon
    2.5 bya

    Photosyntheis = first life

    first single celled organisms
  26. Phanerozoic Eon
    570 mya- now

    • visible life
    • simple multicellular fossils
  27. Precambrian TIme
    Proterozoic Eon- origin of Earth

    4.6 -2.5 bya?
  28. Phanerozoic Eon
    Cenozoic/Mesozoic/Paleozoic Eras

    570 mya- now
  29. Paleozoic Era
    • "ancient life"
    • Age of Invertabrates

    570 mya
  30. Mesozoic Era
    • "Middle Life"
    • Age of Reptiles
    • Dinos are dominant

    225 mya
  31. Cenozoic Era
    • Recent Life
    • age of mammals

    66.4 mya- now
  32. order of time
    • Precambrian Time: Origin of Earth
    • Proterozoic Eon
    • Phanerozoic Eon: Paleozoic Era
    • Mesozoic Era
    • Cenozoic Era
  33. Index Fossil
    used for determining the age of rock layers

    ****must be common widespread geography exist for a limited time period****
  34. zoic
    life; living things
Card Set
Rocks, Rossils, etc,..
fossils, rocks