Aging
The age of a rock, object, or event in years.
What is absolute age?
The geologic processes that took place in the past are generally similar to those that take place now.
What is Uniformitarianism?
A crack of weakness in Earth’s crust along which movement occurs during an earthquake.
What is faulting?
Atoms of the same element that have different numbers of neutrons.
What is an isotope?
Matching nearby rock layers that appear to be the same type and thickness.
What is walking the outcrop?
88% of Earth's history was spent in this era, where no fossils are found.
What is Precambrian Eon?
The age of rocks or events compared to the age of other rocks or events.
What is relative age?
Sediments are deposited in horizontal layers that are parallel to the surface they were deposited on.
What is Principle of Original Horizontality?
Formally horizontal rock layers that have been tilted at an angle by crustal activity.
What is tilting?
Surface of exposed bedrock
What is an outcrop?
Volcanic eruptions leave a layer of ash between rock layers.
What is volcanic markers?
1% of Earth's history is spent in this era where fossils of modern plants and mammals can be found.
What is Cenozoic Era?
I am 50 years old is an example of what type of age?
What is absolute age?
In undisturbed layers, the oldest layer is on the bottom and each overlying layer is younger.
What is Principle of Superposition?
As hot magma squeezes into cracks and zones of weakness, the cooling magma passes its heat energy to the nearby rock.
What is igneous intrusions & extrustions?
The geological process in which transported sediments, soil, rocks, and organic matter are dropped or settle in a new location.
What is deposition?
Matching the color, texture, and composition of the rock strata.
What is comparing properties?
4% of Earth's history was spent in this era where evidence of dinosaurs, early birds, and early mammals can be found.
What is Mesozoic Era?
What is relative age?
A disruption that cuts through rock or another geologic feature must be younger than the rock or the other geologic feature.
What is Law of Cross-Cutting?
Layers of sedimentary rock that have been bent or warped by crustal forces.
What is folding?
The amount of time it takes for HALF of the atoms in a radioactive sample to decay.
What is half-life?
Fossils of organisms that lived over a wide geographic area for a relatively short period of time.
What is index fossils?
7% of Earth's history was spent in this era where invertebrates, fishes, amphibians, vertebrate, land plants, and land animals all appear.
What is Paleozoic Era?
Process of carrying away weathered rock materials causing a gap in the rock record.
What is erosion?
An unstable radioactive isotope will break down into another more stable element.
What is radioactive decay?
A gap in the rock record cause by the burial of an eroded surface by younger sediments. Shown on rock outcrop by a wavy line.
What is unconformity?
Matching rocks and geologic events in one location with rocks and geologic events in other locations.
What is correlation?
Change from simple forms to more complex forms.
What is evolution?
The era in which humanoids first appeared.
What is Cenozoic Era?