Geology Quiz 2: Chapter 4

Question 1

Define erosion:

Answer 1

states if processes continue as they do today, everything will eventually be eroded or worn away

Question 2

Define petrification

Answer 2

the process by which trees, plants, and even animals are solidified by burial in hot silica-rich water.

Question 3

Define turbidite

Answer 3

a underwater, rapid deposition of mud which hardens into a layer of rock

Question 4

Define gastrolith

Answer 4

rounded stones which were used by plant-eating dinosaurs to aid in digestion and sometimes found with fossilized remains

Question 5

Define fumaroles

Answer 5

an opening in earth’s crust, usually associated with volcanic activity

Question 6

Define carbon dating

Answer 6

a process which uses the decay of carbon 14 to estimate the age of things that were once living

Question 7

List the five primary causes of normal erosion.

Answer 7

rain, ice, plants and animals, chemicals, ocean waves

Question 8

Name the different types of fossils.

Answer 8

hard parts are preserved; replacement by other minerals; cast or mold are all that remains; petrification; carbonization; preservation of soft parts; frozen animals; animal tracks and worm burrows; coprolites; gastroliths

Question 9

What are unstable atoms called? What is the most well-known radioactive atom?

Answer 9

radioactive; uranium

Question 10

Sand is made primarily of what mineral?

Answer 10

silica

Question 11

How is turbidite formed?

Answer 11

First, an event such as an earthquake starts a mud flow underwater. Next, the mud flow spreads out. Eventually the mud flows hardens into a layer of rock.

Question 12

What factors influence whether a rock will bend or break?

Answer 12

Whether it is soft or brittle, how deep it is buried

Question 13

What is the main condition required for a fossil to form?

Answer 13

The organism must be buried rapidly, protected from scavengers and from decomposition by bacteria and chemicals

Question 14

Describe how sedimentary rocks are formed.

Answer 14

First, layers of sediment are deposited. The weight of the water and the sediments on top begin to compact the sediments underneath. Next, warm water circulates throughout the sediments and dissolves certain minerals. The dissolved minerals surround the individual grains of sediment. Finally, when the water cools off and stops moving, the dissolved minerals act as a “glue” that cements the grains of sediment together to form sedimentary rock.

Question 15

Describe how metamorphic rocks are thought to form.

Answer 15

Heat and pressure recrystallize the minerals in rock into new mineral combinations. Some believe it happened over long periods of time; others believe it happened over short periods of time.

Question 16

Explain the process of carbon dating in determining when a plant died.

Answer 16

When a plant is living, it takes the isotope carbon 14 into its leaves, stems, and seeds. After the plant dies, the carbon 14 decays into nitrogen 14. Scientists can measure the amounts of both carbon 14 and carbon 12. Since they know the time it takes the isotope to decay, they can calculate when the plant died.