The Earth and Geological Time Flashcards
What is the difference between P waves and S waves?
P = Primary, Longitudinal waves
S = Secondary, Transverse waves
What is a stratum?
A distinct layer of sediment
What is an uncomformity?
A substantial break or gap in a stratigraphical sequence
What is an angular uncomformity?
Older rocks are deformed and eroded before new sediment is laid.
What is a disconformity?
Irregular erosion surface between parallel layers (no tilting)
What is a nonconformity?
When younger strata overlie igneous or metamorphic rock
What is the law of original horizontality?
Water laid sediments are deposited in strata that are horizontal or nearly horizontal
What is the principle of stratigraphic superposition?
Any sequence of sedimentary strata is deposited bottom to top
What is a formation?
A collection of similar strata that are sufficiently different from above/below
What is the time stratigraphic record?
Classification based on rocks formed within a time
What is the order of the 4 eons?
Hadean, Archean, Proterozoic, Phanerozoic
What defines the Hadean eon?
Earliest Eon of Earth’s history, no rock record
What defines the Archean eon?
Oldest rocks on Earth from this eon, contain primitive microscopic life forms
What eras is the phanerozoic divided into?
Paleozoic, Mesozoic, Cenozoic
Continue the order of division: Eons, Eras….
Eons, Eras, Periods, Epochs, Stages
