Sedimentary Rock Mineral Geologic History
This chapter study is about sedimentary rocks, stratification, metamorphic rock, halite crystal (rock salt), mineral identification, geologic history, biggest agent of erosion, mechanical weathering, mineral fluorite, Uniformitarianism, absolute age of a rock, composition of the Earth.
A sedimentary rock that is composed of material evaporated from seawater is described as __________.
- foliated
- organic
- clastic
- chemical – correct
Sedimentary rocks are often formed in layers. What is this layering called?
- stratification – correct
- nonfoliation
- foliation
- ripple marks
How does a rock change into a metamorphic rock?
- evaporation
- cooling of magma
- heat and pressure – correct
- cementation and compaction
Why is coal not classified as a mineral?
- It is does not occur naturally.
- It is not a solid.
- It is made of organic material. – correct
- It has no crystal shape.
Which mineral property is easily observed, but can be unreliable when it comes to mineral identification?
- cleavage
- streak
- color – correct
- hardness
Which mineral property describes a mineral’s resistance to being scratched?
- fracture
- streak
- hardness – correct
- cleavage
A rock containing valuable minerals that can be mined is called __________.
- a jewel
- an ore – correct
- an igneous rock
- a sedimentary rock
What are elements that lose electrons and form positive ions called?
- minerals
- metals – correct
- nonmetals
- ores
To which of the six crystal systems does a halite crystal (rock salt) belong?
- tetragonal
- monoclinic
- cubic – correct
- pentagonic
How do igneous rocks form?
- compaction and cementation of sediment
- evaporation of seawater
- heating and added pressure to existing rock
- cooling of molten lava or magma – correct
Which type of sedimentary rock is formed from fragments of minerals or rocks?
- intrusive
- organic
- clastic – correct
- caustic
How are igneous rocks classified?
- by texture and composition – correct
- by the degree of foliation
- by cooling rate
- by color
The metamorphic rock marble will dissolve in the presence of a weak acid. Which rock probably was changed into marble by the addition of heat and pressure?
- granite
- sandstone
- shale
- limestone – correct
A metamorphic rock has grains arranged in parallel layers or bands. What property is this rock displaying?
- nonfoliated
- layering
- stratification
- foliation – correct
An igneous rock is composed primarily of quartz and feldspar. What type of magma most likely formed this rock?
- felsic – correct
- plutonic
- volcanic
- mafic
Which of the following is involved in weathering?
- seafloor spreading
- mountain building
- water – correct
- volcanoes
What types of rocks initially form from deposition?
- basaltic
- igneous
- metamorphic
- sedimentary – correct
Air, water, and ice can break rocks into tiny fragments. Which of the following best describes this process?
- weathering – correct
- deposition
- erosion
- sediment
What characteristic makes a substance a mineral?
- It is found in certain rock strata.
- It is a liquid, solid, or gas.
- It has a crystal structure. – correct
- It is only an organic compound.
Which mineral property can be determined simply by observation?
- magnetic properties
- luster – correct
- reaction to acid
- hardness
When a rock is altered by extreme heat and pressure, what type of rock is the result?
- sedimentary
- clastic
- metamorphic – corrrect
- igneous
A mineral that occurs in a quantity that is economically worthwhile to mine is called __________.
- an ore – correct
- a gem
- a gemstone
- a metal
Most minerals on earth’s surface contain which of the following?
- oxygen and silicon – correct
- sulfur and hydrogen
- silicon and nitrogen
- nitrogen and oxygen
How would you best describe the texture of an igneous rock that formed extremely slowly underground?
- glassy
- fine grained
- pegmatitic – correct
- porphyritic
In which environment might you expect a deposit of rock salt or rock gypsum to have formed?
- fast moving stream
- deep ocean
- coastline
- shallow sea – correct
Which of the following is not an external force that acts on rocks in the rock cycle?
- water
- ice
- wind
- pressure – correct
In addition to subduction, what changes sedimentary rocks to metamorphic rocks?
- temperature – correct
- wind
- gravity
- nitrogen
Where may sediments be deposited?
- at a divergent plate boundary
- in a river delta – correct
- in a newly formed mountain
- at a convergent plate boundary
What is formed by weathering, erosion, and deposition?
- sand dunes – correct
- mountains
- volcanoes
- grasslands
How is mechanical weathering best described?
- the breakdown of rock through decomposition of chemicals
- the buildup of rock formations over time
- the buildup of chemical deposits on the surface
- the breakdown of rock through mechanical disintegration and physical stress – correct
Which is the biggest agent of erosion?
- gravity
- water – correct
- pollution
- tornadoes
Which of the following colors of soil is the best for a wildlife habitat?
- brown
- gray
- red
- black – correct
Inappropriate land use, such as removing vegetation from hillsides and plowing fields parallel to a hillside, may contribute to which of the following?
- increase in weathering of the landscape
- decrease in amount of toxins in the soil
- decrease in water runoff
- increase in erosion – correct
Is this statement true or false?
A gemstone is a hard, colorful mineral with a glassy or shiny luster.
- true – correct
- false
An ore is a rock that contains which of the following?
- particles of rock that erode into sediment
- a mineral or metal with no practical use
- a mineral or metal with economic usefulness – correct
- a gemstone only
The mineral fluorite is used in the process to make __________.
- watches
- kitty litter
- optical microscopes
- steel and aluminum – correct
Is this statement true or false?
Strip mining is less harmful to the environment than shaft mining, but more dangerous to miners.
- true
- false – correct
Is this statement true or false?
Mining companies must restore the land that they use, especially in openpit mining. Mining companies may also have to clean up the water or replace the disturbed soil.
- true – correct
- false
Is this statement true or false?
Uniformitarianism is the concept that the processes that are at work on earth today are the same processes that shaped the early history of earth.
- true – correct
- false e
If you wanted to study climate change, which fossil would be most useful? A fossil of an organism that is __________.
- large and difficult to find, but resistant to temperature change
- small, hard, abundant, resistant to temperature change, and easily preserved
- large and difficult to find, but sensitive to temperature change
- small, hard, abundant, sensitive to temperature change, and easily preserved – correct
Is this statement true or false?
The fossil record provides evidence of past life as well as clues to the past climate, environment, and abiotic factors in an area.
- true – correct
- false
Which of the following is the primary technique for determining the absolute age of a rock?
- measuring the dimensions of the rock
- comparing the rock to other geologic features
- comparing the rock to similar rocks and noting the differences
- measuring radioactive decay of element isotopes – correct
The disappearance of organisms from the geologic record provides evidence for which of the following events?
- a change in climate
- periods of mass extinction – correct
- a change in sea level
- continental drift
What does the theory of uniformitarianism state?
- Evidence from fossils can give us glimpses into the past.
- Major catastrophic events shaped the earth.
- Earth has not changed for billions of years.
- Geologic processes we see today were also at work in the past. – correct
Geologists frequently look at the relationships among rock layers. Which statement best describes the information geologists get from studying these relationships?
- They get a sense of the history of the area they are investigating. – correct
- They can tell how dense the rocks are.
- They can tell how old the rocks are.
- They get a sense of which rocks are the most valuable.
Which of the following could be used to interpret the geologic history of a location?
- human settlements
- animal habitats
- plant life
- rock layers – correct
Suppose you are hiking in the hills and you come across a wall of rock. You look closely at the rock and you notice a Trilobite fossil embedded in it. What might this fossil suggest to you about the hills you are hiking in?
- The hills are rich in sandstone.
- The hills, at one time, were under water. – correct
- The hills were once at a much higher elevation.
- The hills used to be volcanic and are now dormant.
Volcanic rock has often been found early in the rock record but less frequently in later rock layers. What does this suggest to scientists about early earth?
- Volcanic rock is more easily preserved than other kinds of rock.
- Volcanic activity is the same today as it was early in earth’s history.
- Volcanic activity was more common in the past than it is today. – correct
- Volcanic rock is easier to find.
Which of the following events separate geologic time into eras and periods?
- the appearance and disappearance of groups of organisms – correct
- the creation of new ocean ridges
- the appearance and disappearance of volcanoes
- the number of earthquakes occurring at that time
Fossils in Precambian rocks are rare, while there are many fossils in rocks from the Phanerozoic eon. What does this evidence suggest?
- The rocks from the Phanerozoic eon are much harder than those from the Precambrian eon.
- There was no change in the diversity of life in the Phanerozoic eon.
- There was a major change in the diversity of life in the Phanerozoic eon. – correct
- There was no life in the Precambian eon.
Only a small portion of the organisms that lived in the geologic past have been preserved as fossils. Which condition best increases the chance that an organism will become fossilized?
- rapid burial and hard body parts – correct
- slow burial and large body size
- rapid burial and large body size
- slow burial and hard body parts
What does the presence of dinosaur footprints in an area where no dinosaur bones were found suggest?
- Dinosaurs were never in that area.
- The area was once underwater.
- The climate was too hot for dinosaurs.
- Dinosaurs were at some time in the area. – correct
A large piece of rock contains a thick-shelled clam fossil. What evidence does this fossil best provide?
- evidence of the size of the clam population in the past
- evidence of the environment of the past in the area where the rock was found – correct
- evidence of the mating habits of clams in previous geologic eras
- evidence of the change in diet of the thick-shelled clams over time
Fossils of the reptile Mesosaurus have been found in both Africa and South America. Which of the following is a likely explanation for the fossils being found in these two places?
- The reptile was able to swim across the Atlantic Ocean.
- Africa and South America are joined and so the reptiles can walk from one to the other.
- The fossils were moved by humans from Africa to South America.
- Africa and South America were once joined and later broke apart. – correct
A scientist is interested in comparing the age of a rock with other rocks. By doing this, the scientist is determining __________.
- the relative age of the rock – correct
- the absolute age of the rock
- the date the rock was formed
- the level of radioactive isotope decay in the rock
In the diagram, which layer of rock is the oldest?
- J
- D
- F – correct
- Z