Canyons
haha this isn't about canyons.
Name at least three steps of fossil formation.
- Dead matter covered with sediment.
- More sediment layers deposited on top of it.
- Dead matter decomposed
- Minerals filled the space left behind.
- Water (ocean or lake) presses down on it.
- Turns into sedimentary rock.
Which marks on a rock are evidence of glacial abrasion?
A. Scrapes with no pattern
B. Scrapes with a perpendicular pattern
C. Scrapes with a parallel pattern
D. Scrapes are not evidence of glaciers
C. Scrapes with a parallel pattern
What type of rock material probably makes up layers 1, 2, 3 and 4? (slide 18)
Sedimentary rock because of the horizontal layers.
What are the steps of sedimentary rock formation (in order)?
erosion, deposition, compaction and cementation
How are igneous rocks formed?
Magma cooling
What is the source of the energy that drives most weathering?
A. Plants
B. Humans
C. The Earth’s core
D. The Sun
D. the sun
Which process(es) can glaciers perform?
A. Weathering (breaking down existing rock material)
B. Erosion (moving sediments)
C. Deposition (leaving sediments in new places)
D. All of the above
D. ALL OF THE ABOVE
How does the age of the shelled fossil relate to the age layer 2? (slide 24)
Same age
Chinese Towers:
These structures are made of limestone, a soft sedimentary rock. How might they have formed? (slide 16)
Limestone formed through erosion, deposition, compaction and cementation. These were later uplifted through tectonic activity. Then, weathering occurred to break down some of the rock.
Weathering is the breaking of bigger rock into sediments. Erosion is the carrying of the sediments.
What are the white squiggles on the right wall of the canyon? What kind of rock are they? (slide 4)
The white squiggles appear to be igneous rock formed by cooling magma.
If you said sedimentary rock turned to igneous, that is reasonable too.
Is there evidence in this image that this area used to be significantly colder than it is today? If so, what is it? (slide 12)
Yes, this appears to be a u-shaped valley - so there used to be a glacier here.
Speculate as to the type of rock material that make up the structure indicated by the arrow. (slide 20)
Igneous rock - its an intrusion formed by magma that cooled
Devil’s Tower, Wyoming:
What two (2) types of rock material appear to be visible in the image? What is your reasoning?
(Rock materials include: sedimentary rock, sediments, igneous rock, magma and metamorphic rock)
(slide 6)
sediments - loose, broken off pieces at the bottom
igneous rock - vertical striping is not usually seen in sedimentary rock, and there is no metamorphic folding.
Which of the following is true about the location of fossil fuels? Choose all that apply.
A. They are found in sedimentary rocks.
B. They are found in igneous rocks.
C. They are found near ancient swamps and oceans.
D. They are evenly distributed around the world.
E. They are unevenly distributed around the world.
A. They are found in sedimentary rocks.
C. They are found near ancient swamps and oceans.
E. They are unevenly distributed around the world.
erosion by wind and water
Assuming there WAS a glacier in New England years ago, what other evidence might a scientist find if they were to look closer?
[See if you can come up with at least 2 of the 3 possibilities.]
- Glacial scrapes on bedrock
- Moraines or other sediment piles.
- Boulders of a type of rock not found in the area
Which layer shows evidence of weathering? How do you know? (slide 22)
Layer 1 - very bumpy
Devil's Tower, Wyoming:
What you can't see is that the soil in the fields around Devil's Tower is covering layers of sedimentary rock. Also, the Devil's Tower formation goes deep, deep into the crust. There is no evidence that it could have been moved there by a glacier; it formed in this location. We also know that magma can't form a tower in the air.
How did it form? (slide 8)
A. Many sedimentary rock layers formed, then there was an igneous rock cross cut, and then some of the sedimentary layers weathered and eroded away.
Why is the rock behind the tree wider at the top than at the bottom? (slide 33)
Differential weathering - the rock at the top resists abrasion weathering more than the rock at the bottom based on hardness or position.
How did this canyon form? (slide 2)
Canyons are formed by sediments in fast flowing rivers that carve the rock deeper and deeper. Canyons get wider due to freeze-thaw wedging and water abrasion caused by water flowing over the sides of the canyon.
haha this one isn't about glaciers and valleys...
Geologists found fossils of a tropical plant in Antarctica. What do these fossils tell us about what Antarctica used to be like?
It used to be warmer
Is the igneous cross-cut older or younger than layer 3? How do you know? (Slide 28)
Younger - it passes straight through all the sedimentary layers.
Devil's Rock, Wyoming:
Based on what you know, is there evidence that there used to be a lake, sea or ocean nearby? Explain your reasoning.
Yes, the best evidence for an ancient body of water is the existence of sedimentary rock.
Describe the process of frost wedging.
Rain fills the crack. When it gets cold enough, the water will freeze and expand. This has to happen over and over again with the crack getting bigger each time.