Earth Science

Weathering and erosion are processes that constantly change Earth’s surface. How do weathering   and erosion differ?

• Weathering acts quickly. Erosion acts slowly
• Weathering acts underground. Erosion acts above ground.
• Weathering breaks down materials. Erosion moves materials.
• Weathering is caused by wind. Erosion is caused by water.

A sedimentary rock unit was exposed to heat and pressure deep within Earth. The rock changed to metamorphic rock. Over a long time, it was exposed at Earth’s surface. How did this metamorphic rock unit reach Earth’s surface? 

• Deposition acted on the rock unit, causing it to be exposed at the surface over time.
• Magma brought it up to Earth’s surface, where it flowed from a volcanic vent as lava.
• Weathering and erosion of the rock above it caused the metamorphic rock to uplift and become exposed.
• Weathering of the metamorphic rock brought pieces up to Earth’s surface.

Many processes help to shape Earth’s surface. Starting with a rock, in what order would you  expect the following Earth processes to occur?

• deposition, eruption, weathering
• erosion, weathering, deposition
• eruption, erosion, weathering
• weathering, erosion, deposition

All of the trees next to a stream are chopped down, leaving only rocks and soil. A paved parking lot is built next to the stream. What might cause the water in the stream to be cloudy following the next rain?

• increased groundwater under the area
• decreased abrasion from the pavement
• increased erosion along the edges of the stream
• increased erosion from the pavement being weathered

How does a delta form?

• It forms when sediments are deposited at the mouth of a river.
• It forms when sediments are carried away from an ocean or lake.
• It forms when sediments are deposited at the base of a mountain. 
• It forms when sediments are deposited along the banks of a river. 

The Florida Keys are in part made up of the skeletons of once-living organisms called corals.  How might the development of glaciers have contributed to the formation of the Keys?

• Melting glaciers caused sea levels to rise, increasing the growth rates of corals.
• As more water was frozen in glaciers, sea levels dropped, killing corals.
• Melting glaciers reduced ocean temperatures, increasing the growth rates of corals.
• As more water was frozen in glaciers, ocean temperatures rose, killing corals.

 Fossils are the preserved remains of organisms that lived long ago. According to the law of superposition, the rock layers that contain fossils should be far below Earth’s surface. Which answer best explains why fossils are sometimes found at or near the surface? 

• Fossils are less dense than rock, so they rise to the surface.
• Fossils are moved to the surface by other organisms.
• Sedimentary rock layers are relatively soft, and new fossils sink through upper layers into older, deeper layers.
• Some rock layers with fossils have been exposed because of different processes, such as faulting, folding, and weathering.

The rock layers that make up the Grand Canyon range in age from 2 billion to 230 million years. What would a scientist need in order to compare the ages of rocks from two different parts of the canyon? 

• the location of each rock
• the size and hardness of each rock
• the size of the crystals that make up each rock
• the amounts of radioactive elements in each rock

The Appalachian Mountains are believed to have been as high as the Himalayas at one time. Which two processes are responsible for the fact that they are now much smaller? 

• deposition and tectonics
• erosion and tectonics 
• weathering and deposition
• weathering and erosion 

Sand dunes form along some coastlines. Which factor is most responsible for forming sand dunes?

• rain
• wind
• water
• ice