Geological time scale Deformed Laws and Principles Name the picture Stress
Periods divided into smaller units.
What are epochs?
A basic unit of the geological time scale that is a subdivision of an era. They can also be divided into smaller units called epochs.
What are periods?
The era that began about 65 million years ago.
What is the Cenozoic era?
The era that began about 540 million years ago.
What is the Paleozoic era ?
A term derived from Greek words meaning visible life.
What is Phanerozoic ?
Tilted or folded sedimentary rocks that are overlain by younger, more flat-lying strata.
What is angular unconformity?
More common but usually far less conspicuous because the strata on either side is essentially parallel.
What is disconformity ?
The deposition of sediments that have been interrupted over and over again.
What is unconformity?
Layers of rock that have been deposited without being interrupted.
What is conformable?
An unconformity in which older metamorphic or intrusive igneous rocks are overlain by younger sedimentary strata.
What is nonconformity?
Simply states that in an undeformed sequence of sedimentary rock, each bed is older than the one above and younger than the one below.
What is law of superposition?
Layers of sediments are generally deposited in a horizontal positon.
What is the principle of orginal horizantality?
When a fault cuts through other rocks, or when magma intrudes and crystalizes, we can assume the fault or intrusions is younger than the rocks effected.
What is the principle of cross- cutting relationships?
Steno was credited with recognizing the importance of this principle.
What is the principle of original horizontality?
Organisms succeed one another in a definite and determined order, and therefore any time period can be recognized by its fossil content
What is principle of fossil succession?
What is an anticline?
What is a syncline?
What is a normal fault?
What is a reverse fault?
What is a thrust fault ?
Forces that are equal in all directions
What is uniform stress?
When stress is applied unequally from different directions.
What is differential stress ?
This stress, associated with plate collisions tend to shorten and thicken Earths crust by folding, flowing and faulting.
What is compressional stress?
Stress that tends to elongate or pull apart a rock unit.
What is tensional stress?
Often occurs on closely spaced parallel surfaces of weakness, such as bedding planes, foliation and micro faults
What is shear stress?