Making Sense of Geologic Record

Home > Flashcards > Print Preview

The flashcards below were created by user DrGirlfriend on FreezingBlue Flashcards. What would you like to do?

  1. Describe the different ways that rocks can be split up into stratigraphic units
    • 1.) Lithostratigraphy
    • - by physical attributes of rocks (like grain size, color, sorting, type, fossils)

    • 2.) Biostratigraphy
    • - by index fossils (chunking time based on fossils)

    • 3.) Chronostratigraphy
    • - by time of deposition (layers, radioactive dating)
  2. What is a formation?
    A basic unit for lithostratigraphy.

    • It must have:
    • - distinct upper and lower boundary (drastically different lithology/rock characteristics)
    • - laterally continuous (large event that occurred over a long period of time)
    • - mappable on a standard scale (not tiny, not covering half of the US)
  3. Steno's Three Laws, and other laws for relative dating of rocks
    • 1.) Principle of Superposition
    • - oldest is on the bottom (especially true for sedimentary layers)

    • 2.) Principle of Original Horizontality
    • - layers form horizontally (originally deposited flat)
    • - applies to sedimentary rocks (because they can't form at angles)
    • - not flat = major tectonic activity

    • 3.) Principle of Lateral Continuity
    • - layers are deposited, and then something else disturbs it (river cuts through) and layers are no longer connected, but still formed at the same time

    • 4.) Principle of Cross-Cutting Relationships (the other law)
    • - younger features can cross-cut older features/rocks
    • - faults cut layers = younger
    • - igneous intrusions

    • 4.) Principle of Inclusion
    • - a younger unit can contain pieces (clasts) of an older rock unit

Card Set Information

Making Sense of Geologic Record
2014-02-09 20:45:17
geology 1020
Geology Unit 2 Learning Goals
Show Answers:

What would you like to do?

Home > Flashcards > Print Preview