Sedimentary rocks are deposited in horizontally.
What is the principle original horizontality?
What is an exception to the principle of original horizontality?
Younger rocks are deposited on top of older rocks.
What is principle of superposition?
Rocks have been tilted or folded.
When does the principle of superposition not apply?
A intrusion that cuts a rock must be younger than the rock.
What is the principle of cross-cutting relationships?
Graded beds and mud cracks.
What are 2 signs of the "top" side of the rock?
A gap in the geologic record.
What is an unconformity?
Nonconformity, disconformity and angular unconformity.
What are the 3 types of unconformities?
Erosion surface separating older igneous rocks from sedimentary rocks.
What is a nonconformity?
Separations in parallel beds when some older rock below were removed.
What is a disconformity?
Rocks above the unconformity are at a different angle than those below.
What is an angular unconformity?
Fossils succeed each other vertically in a specific and reliable order.
What is principle of faunal and flora succession?
They were widely distributed but existed for a short span of geologic time.
What are index fossils?
It decays to form daughter elements at a fixed rate regardless of conditions.
What is the parent element?
Once it crystallizes.
When does the parent element's clock begin?
The amount of time it takes for ½ of the parent element to decay.
What is half-‐life?
The preserved remains of evidence of past life.
What is a fossil?
What is the minimum age of a fossil?
Original collagen I and organic structures.
What must be persevered for something to qualify as a fossil?
What type of rock are fossils found in?
Mudstone, shale and siltstone.
What sedimentary rocks form in oceans, lakes and floodplains?
What sedimentary rock forms in near-shore environments?
What sedimentary rock forms in warm, shallow marine environments?
Study of decaying organisms and if/how they become fossils.
What is taphonomy?
Transport, burial and microbial attack.
What are three processes that taphonomy looks into?
The actual body parts of an organism that has been preserved.
What are body fossils?
What type of fossils can be altered or unaltered?
Fossils that have gone through a chemical or physical change.
What is an altered body fossil?
The remains have gone through little or no chemical or physical change.
What is an unaltered body fossil?
Gastropod shells are considered what type of fossil?
The hard parts of remains that minerals dissolved in water can soak into and collect on them.
What is permineralization?
Silicification and Pyritization.
What are the two most common types of permineralization?
Groundwater with dissolved minerals replace the hard parts of organisms.
What is replacement?
A chemical change of the atoms that make up the hard parts.
What is recrystallization?
Soft parts that get buried in sediment where they get preserved under pressure.
What is carbonization?
Permineralization, replacement, carbonization and recrystallization.
What are the four ways to alter a body fossil?
Indirect remains of fossils.
What are trace fossils?
The imprint of an organism in the rock that is fossilized.
What is a mold?
The original parts are dissolved and the space is filled with sediment or minerals.
What is a cast?