Geologic Time/Eras
What is the geologic time scale?
The geologic time scale is a record, in chronological order, of all the life forms and geologic events in Earth's history.
The products of weathering are called this.
Sediments
The preserved remains of something that was once living.
Fossils
This is the process of determining the order of past events compared to other events.
Relative Dating
This is the name of the proposed "supercontinent" where all the earth's continents were once joined together.
Pangaea
True or False? Explain your answer. Humans were dominant for most of geologic time.
False. If you tried to squeeze Earth's 4.6-billion year history into a 24-hour day, modern humans don't even appear until less than a second before midnight!
How does sedimentary rock form?
Weather, Erosion, Deposition, Compaction & Cementation
If a fossil is found in a particular rock layer, what can we say about both the fossil and the rock layer?
The formed at the same time.
This states that younger rocks always lie above older rocks.
Law of Superposition
These are the two types of crust found on earth
Oceanic and Continental
How is geologic time divided?
Eons, Eras, Periods & Epochs
Why are fossils only found in sedimentary rock?
Fossils would be destroyed by heat and/or pressure during the formation of igneous and metamorphic rocks. Sedimentary rocks are formed when sediments build, layer upon layer, and gradually cement and harden. Fossils can easily become trapped and preserved in the layers.
What kinds of information do Paleontologists get from fossils?
Paleontologists use fossils to help them determine what past life forms were like, how they changed over time, how the Earth's surface has changed and what the past environments were like.
This is a break in the geologic record. (when a rock layer is missing)
Unconformity
This type of plate boundary involves two plates moving toward each other.
Convergent
During what era did the Age of Mammals begin?
Cenozoic
When igneous rock forms inside of a fossil layer, what is it called?
Intrusion
What is an index fossil, and why is it helpful in determining relative age?
An index fossil is the fossil of an organism that is widely distributed (not just found in a limited area) and lived only a short period of time. Because they live only a short period of time but are found all over the place, they are helpful in telling the relative ages of the rocks in which they occur.
This is a break or crack in a layer of rock.
Fault
This type of plate boundary involves one plate sliding past another plate.
Transform
This was the longest Era in Earth's history
Precambrian
This is the process that carries sediments away.
Erosion
All of the following conditions help preserve fossils EXCEPT
A. quick burial of organism
B. only hard parts used for fossil
C. left for a short period of time
D. weathering/erosion bring the fossil to the surface
C
This states that a crack or break in rock must be younger than the rock layer it cuts through
Law of Cross-Cutting
These are the 4 types of evidence that were initially used to support the Theory of Continental Drift.
Continental Fit, Fossils, Glacial Evident, Landforms/Rock Layers