Geologic Time Scale
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A Paleontologist uncovers a bed of fossils in the continental United States. The bed of fossils is full of shells and sea creatures, but the paleontologist is nowhere near the ocean. How is this possible?
there was a body of water there at one point
the fossils were deposited there by rivers
animals carried the fossils there
they are probably false fossils, or just rocks that look like shells
Explanation
The answer is "There was a body of water there at one point." Due to continental drift and changes to Earth's geography over time, oceans and lakes are in different places today than they were many millions of years ago.
Scientists date and categorize fossils to determine when the organisms lived relative to each other. The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years. Fossils are found in rocks and can be formed from hard parts of organisms, such as bones and shells, but soft parts do not form fossils well and fossils of body parts like feathers are much more rare.
One pattern in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. This means that the fossil record provides evidence for evolution and it shows tiny changes in the structures of organisms as time moved forward.
Major extinction events and natural disasters such as drought or volcanic eruptions can also be seen in the fossil record. Notably the fossil record has large amounts of iridium in the layer titled The 'K–T Boundary' or 'end Cretaceous event', which marks the extinction of the dinosaurs on land. Scientists believe this extinction was the result of a large meteor striking Earth.
The end of an "era" in the geologic time scale is usually marked by what?
a mass extinction
sudden tectonic activity
a meteor
a drastic change in geography
Explanation
The answer is "a mass extinction."
Scientists date and categorize fossils to determine when the organisms lived relative to each other. The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years. Fossils are found in rocks and can be formed from hard parts of organisms, such as bones and shells, but soft parts do not form fossils well and fossils of body parts like feathers are much more rare.
One pattern in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. This means that the fossil record provides evidence for evolution and it shows tiny changes in the structures of organisms as time moved forward.
Major extinction events and natural disasters such as drought or volcanic eruptions can also be seen in the fossil record. Notably the fossil record has large amounts of iridium in the layer titled The 'K–T Boundary' or 'end Cretaceous event', which marks the extinction of the dinosaurs on land. Scientists believe this extinction was the result of a large meteor striking Earth.

What geographic feature would be expected to appear where the star is on this diagram of plate movement?
a volcano
a mountain
a mid ocean ridge
a canyon
Explanation
The answer is "a volcano."
Earth’s crust, also called the Lithosphere, is divided into tectonic plates. These plates move at plate boundaries due to the liquid hot mantle beneath the crust.
Plates interact at three types of plate boundaries: divergent, convergent and transform. Most of the Earth's geologic activity takes place at plate boundaries.
Divergent: extensional; the plates move apart. Spreading ridges, basin-range.
Convergent: compressional; plates move toward each other.
Transform: shearing; plates slide past each other. Strike-slip motion.
At a divergent boundary, volcanic activity produces a mid ocean ridge and small earthquakes. Convergent boundaries create mountains, and transform boundaries cause earthquakes as well
Which of the following best describes what happens at a strike-slip fault?
shearing motion; plates slide past each other
extensional motion; the plates move apart, spreading ridges, basin-range
compressional motion; plates move toward each other
none of these
Explanation
Earth’s crust, also called the Lithosphere, is divided into tectonic plates. These plates move at plate boundaries due to the liquid hot mantle beneath the crust. Plates interact at three types of plate boundaries: divergent, convergent and transform. Most of the Earth's geologic activity takes place at plate boundaries.
Divergent: extensional; the plates move apart. Spreading ridges, basin-range.
Convergent: compressional; plates move toward each other.
Transform: shearing; plates slide past each other. Strike-slip motion.
At a divergent boundary, volcanic activity produces a mid ocean ridge and small earthquakes. Convergent boundaries create mountains, and transform boundaries cause earthquakes as well.

A Paleontologist uncovers a bed of fossils in the continental United States. The bed of fossils is full of shells and sea creatures, but the paleontologist is nowhere near the ocean. How is this possible?
there was a body of water there at one point
the fossils were deposited there by rivers
animals carried the fossils there
they are probably false fossils, or just rocks that look like shells
Explanation
The answer is "There was a body of water there at one point." Due to continental drift and changes to Earth's geography over time, oceans and lakes are in different places today than they were many millions of years ago.
Scientists date and categorize fossils to determine when the organisms lived relative to each other. The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years. Fossils are found in rocks and can be formed from hard parts of organisms, such as bones and shells, but soft parts do not form fossils well and fossils of body parts like feathers are much more rare.
One pattern in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. This means that the fossil record provides evidence for evolution and it shows tiny changes in the structures of organisms as time moved forward.
Major extinction events and natural disasters such as drought or volcanic eruptions can also be seen in the fossil record. Notably the fossil record has large amounts of iridium in the layer titled The 'K–T Boundary' or 'end Cretaceous event', which marks the extinction of the dinosaurs on land. Scientists believe this extinction was the result of a large meteor striking Earth.
The end of an "era" in the geologic time scale is usually marked by what?
a mass extinction
sudden tectonic activity
a meteor
a drastic change in geography
Explanation
The answer is "a mass extinction."
Scientists date and categorize fossils to determine when the organisms lived relative to each other. The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years. Fossils are found in rocks and can be formed from hard parts of organisms, such as bones and shells, but soft parts do not form fossils well and fossils of body parts like feathers are much more rare.
One pattern in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. This means that the fossil record provides evidence for evolution and it shows tiny changes in the structures of organisms as time moved forward.
Major extinction events and natural disasters such as drought or volcanic eruptions can also be seen in the fossil record. Notably the fossil record has large amounts of iridium in the layer titled The 'K–T Boundary' or 'end Cretaceous event', which marks the extinction of the dinosaurs on land. Scientists believe this extinction was the result of a large meteor striking Earth.

What geographic feature would be expected to appear where the star is on this diagram of plate movement?
a volcano
a mountain
a mid ocean ridge
a canyon
Explanation
The answer is "a volcano."
Earth’s crust, also called the Lithosphere, is divided into tectonic plates. These plates move at plate boundaries due to the liquid hot mantle beneath the crust.
Plates interact at three types of plate boundaries: divergent, convergent and transform. Most of the Earth's geologic activity takes place at plate boundaries.
Divergent: extensional; the plates move apart. Spreading ridges, basin-range.
Convergent: compressional; plates move toward each other.
Transform: shearing; plates slide past each other. Strike-slip motion.
At a divergent boundary, volcanic activity produces a mid ocean ridge and small earthquakes. Convergent boundaries create mountains, and transform boundaries cause earthquakes as well
Which of the following best describes what happens at a strike-slip fault?
shearing motion; plates slide past each other
extensional motion; the plates move apart, spreading ridges, basin-range
compressional motion; plates move toward each other
none of these
Explanation
Earth’s crust, also called the Lithosphere, is divided into tectonic plates. These plates move at plate boundaries due to the liquid hot mantle beneath the crust. Plates interact at three types of plate boundaries: divergent, convergent and transform. Most of the Earth's geologic activity takes place at plate boundaries.
Divergent: extensional; the plates move apart. Spreading ridges, basin-range.
Convergent: compressional; plates move toward each other.
Transform: shearing; plates slide past each other. Strike-slip motion.
At a divergent boundary, volcanic activity produces a mid ocean ridge and small earthquakes. Convergent boundaries create mountains, and transform boundaries cause earthquakes as well.
Which of the following would NOT be found in the fossil record?
dinosaur hearts
prehistoric fish teeth
the shells and plates of marine creatures
skeletons of large dinosaurs
Explanation
The answer is "dinosaur hearts" because hearts are soft body parts and do not fossilize well.
Scientists date and categorize fossils to determine when the organisms lived relative to each other. The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years. Fossils are found in rocks and can be formed from hard parts of organisms, such as bones and shells, but soft parts do not form fossils well and fossils of body parts like feathers are much more rare.
One pattern in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. This means that the fossil record provides evidence for evolution and it shows tiny changes in the structures of organisms as time moved forward.
Major extinction events and natural disasters such as drought or volcanic eruptions can also be seen in the fossil record. Notably the fossil record has large amounts of iridium in the layer titled The 'K–T Boundary' or 'end Cretaceous event', which marks the extinction of the dinosaurs on land. Scientists believe this extinction was the result of a large meteor striking Earth.
Fossils are more easily preserved and thus usually found in what type of rock?
sedimentary
igneous
metamorphic
basalt
Explanation
The answer is "sedimentary."
Scientists date and categorize fossils to determine when the organisms lived relative to each other. The resulting fossil record tells the story of the past and shows the evolution of forms over millions of years. Fossils are found in rocks and can be formed from hard parts of organisms, such as bones and shells, but soft parts do not form fossils well and fossils of body parts like feathers are much more rare.
One pattern in the fossil record is the presence of forms with transitional characteristics, arranged in sequential stratigraphic order. This means that the fossil record provides evidence for evolution and it shows tiny changes in the structures of organisms as time moved forward.
Major extinction events and natural disasters such as drought or volcanic eruptions can also be seen in the fossil record. Notably the fossil record has large amounts of iridium in the layer titled The 'K–T Boundary' or 'end Cretaceous event', which marks the extinction of the dinosaurs on land. Scientists believe this extinction was the result of a large meteor striking Earth.