Geology Chapter 7 Test

Which of the following is a correct statement about resources in sedimentary rocks?

-----a) Groundwater mostly resides in the pore spaces between grains and in fractures. b) Oil and natural gas migrate down until they are trapped at depth. c) Coal forms from the burial of deep-water organic shale. d) The most important component of cement comes from siltstone. e) Uranium does not commonly occur in sandstone.

Lime muds and clastic limestone sands are deposits that form carbonate rocks in:

-----a) nearshore environments b) fluvial environments c) deep-sea environments d) swampy environments

A soft, very fine-grained limestone formed via the accumulation of the calcium carbonate remains of microorganisms is known as:

Chalk

What type of rock would form in in plant-rich swamp?

Coal

A sandstone with a pinkish or reddish color that is the result of oxidation of iron-bearing minerals indicates the sand was:

Deposited on land and exposed to air

What type of rock would form in a coral reef?

Limestone

In this section, a lower gray rock is successively overlain by beach sandstone, lagoon mudstone, and limestone. What is the best interpretation of what was going on?

The area was experiencing a transgression

What happens to the majority of sediment being carried by moving water as it enters a standing body (little or no motion) of water?

The sediment gradually settles to the bottom

The angular clasts typical of breccia indicate what about the distance of transport?

a short distance

Loose sand on the continental shelf or shelf slope that becomes unstable and flows downslope as a thick slurry of sediment and water is known as:

a turbidity current

Which of the following environments would likely have clasts smaller than sand?

a weak current

If a rock is poorly sorted, this means the rock contains:

a wide range in the size of the clasts

Which of the following statements is true about clastic sedimentary rocks?

a) Clasts in a conglomerate or breccia can be different rock types or can be all the same rock type. b) The amount of pore space decreases as a sand is compacted into sandstone. c) Siltstone is coarser than shale. ALL TRUE

Which of the following is a good interpretation of the environmental significance of an attribute of a sedimentary rock?

a) Fossils indicate that sediment was deposited in water. b) Large cross beds in well-sorted sandstone usually indicate deposition by wind. c) Mudcracks are formed at the surface d) Large, angular, poorly sorted clasts reflect a very short transport. -----e) All of these.

Choose those statements that correctly describe limestone.

a) Gray or yellowish in color b) Commonly includes shells c) Forms in water from various processes d) Is known as a carbonate -----e) All of these statements are correct

Identify the factor(s) that strongly influence the size, shape, and/or sorting of sedimentary clasts.

a) Steepness of slope b) Sediment supply c) Strength of current d) Agents of transport -----e) All of these

Which of the following rocks is composed of the smallest sedimentary clasts?

a) breccia b) conglomerate -----c) shale d) sandstone e) siltstone

Which of the following is NOT a common type of cement in sedimentary rocks?

a) calcite -----b) pyroxene c) silica d) iron-oxide minerals

Which of the following is the most used sedimentary resource?

a) cement b) salt -----c) sand and gravel d) coal e) petroleum

Which of the following environments is NOT a setting in which limestone forms?

a) coral reefs b) deposition of calcite near springs c) some lakes d) accumulation of the remains of microscopic organisms -----e) all of these are environments in which limestone forms

61. Which environment is least likely to deposit a breccia?

a) debris flow b) landslide c) steep mountain front -----d) meandering river e) glacier

Which of the following processes produce sedimentary clasts?

a) fracturing of bedrock that results in angular pieces b) breaking of round cobbles as they are transported c) scouring and abrasion of bedrock along rivers d) decomposition of granite into quartz grains and clay -----e) all of these

Which of the following can we understand by studying sedimentary rocks?

a) how environments shifted in location through time b) past changes in climate c) past events, such as landslides and earthquakes d) migration of deserts and advances of the sea -----e) all of these

Which of the following is NOT a type of carbonate rock?

a) limestone b) travertine c) dolostone -----d) shale e) a rock formed from a coral reef

Which of the following does NOT correctly match a rock with a possible environment in which that rock forms?

a) salt - evaporation of water b) gypsum - evaporation of water -----c) coal - deep-sea organic-rich black shale d) chert - accumulation of tiny silica-rich creatures e) chert - mixing of seawater and groundwater

Which of the following are NOT common in landscapes formed by carbonate rocks?

a) sinkholes b) fractures widened by dissolution c) caves d) outcrops with pits or holes ------e) all of these are common in carbonate landscapes

Which of the following is a typical way in which siltstone and shale are expressed in the landscape?

a) soft slopes covered by small, loose chips b) slopes covered by loose debris from overlying rocks c) valleys and other low areas carved into the landscape d) badlands -----e) all of these

Which of the following is a characteristic of a regression?

a) the seas move in, covering more land -----b) sand dunes and river sediments can be deposited over marine deposits c) marine sedimentary facies move toward the land d) erosion surfaces on land can be covered by beach sand e) all of these

Which of the following is a characteristic of a transgression?

a) the seas move out, uncovering more land b) sand dunes and river sediments can be deposited over marine deposits -----c) marine sedimentary facies move toward the land d) all of these

Sedimentary environments on land differ because of variations in

a) topography b) local geology c) amount of water ---d) all of these

How does chalk form?

accumulation of microscopic organisms composed of calcium carbonate

How does chert form?

accumulation of silica rich organisms or mixing of seawater and groundwater

Shallow coastal accumulations of sand that rise above the sea as long, narrow islands are called

barrier islands

Which of the following environments would most likely consist of sand and/or rounded cobbles?

beach at A

This sandstone includes shells of marine creatures that live in shallow water. What is the most likely environment in which it formed?

beach next to a sea

Which of the rock layers in this figure was most likely deposited in a shoreline environment?

both layers of tan sandstone

Which of the following is most likely to deposit a conglomerate?

braided river

Sediments with a large amount of sand are most likely at:

braided river at C and delta at D

The rounded clasts in this sedimentary deposit were likely transported:

by a river

The large cross beds in these rocks indicate that the sediment was deposited:

by the wind or a water current

A sandstone containing mostly sand but mixed with rounded pebbles and pieces of shells indicates deposition:

by waves at the beach

What type of industrial product is being produced from limestone

cement

Which environment is least likely to deposit siltstone or shale?

channel of a braided river

What typically happens to the size, shape, and sorting of clasts as they are transported from steep mountains toward more gentle settings?

clasts become more rounded

Which of the following is a common characteristic of carbonate rocks?

commonly subject to a dissolution

Which of the following environments would most likely form limestone?

coral reef at C

Which environment is most likely to deposit a breccia?

debris flow

Which of the following sites would most likely have turbidity currents?

deep seafloor at D

These sandstone beds are interlayered with dark marine shales. What is the most likely environment in which the sandstone formed?

deep water turbidity currents

Which of the following sites would have sand and silt deposited by slowing of the current?

delta at D

A very well sorted sandstone with large-scale cross-bedding indicates the sand was likely:

deposited by wind in dunes

Fine grained clastic rocks are

easily eroded

How does gypsum form?

evaporation of water in a lake or sea

Compared to non-fractured rocks, the rate of weathering in fractured rocks of the same composition is

faster

The deep-sea floor is characterized by sediment dominated by

fine dust and the remains of single-celled organisms

The most common clastic sedimentary rocks are made of the clasts that are

fine grained (smaller than sand)

The typical large clasts found in breccia indicate that the energy levels of the transporting medium were:

high

The effect of transportation on a pebble's particle size is best summarized by which statement?

its size decreases

Which of the following sites would contain the finest grained sedimentary deposits?

lake at E

Which of the following sites would have the slowest moving or least energetic current?

lake at E

Sedimentary clasts are

loose fragments of rocks and minerals

Lithifies can be defined as

loose sediment hardens into sedimentary rock

Which of the following is NOT involved in turning some sediment into sedimentary rock?

metamorphism

Large, angular clasts are most likely at

mountains at A and glaciers at B

Shale is a common sedimentary rock because

one of the places where clay is deposited is very widespread (the seafloor)

Which environment is least likely to deposit sand?

open ocean away from land

Sedimentary rocks are comprised of material that comes primarily from

other locations

Which of the following processes is NOT considered physical weathering?

oxidation

The 2 main processes by which sediment is produced are

physical and chemical weathering

Peat forms from the accumulation of

plant material

How does iron formation form?

precipitation from seawater early in Earth's history

Rocks rich in what mineral tend to have a poor solubility during weathering?

quartz

If you were designing a rock that resisted weathering, which of the following characteristics would it have?

quartz rich rock

In warm, shallow, marine environments, corals and other marine life typically construct:

reefs

Sedimentary facies shift toward the sea as the sea moves out during a

regression

This sandstone includes small rounded pebbles and was deposited far from the ocean. What is the most likely environment in which it formed?

river

What type of rock would you form in this environment, showing a dried up lake bed?

rock salt and other evaporate materials

The sandstone consists of well-sorted sand grains, was deposited on land, and locally contains large cross beds. What is the most likely environment in which it formed?

sand dunes

Most of the exposed surface of the Earth is covered with

sediment and sedimentary rocks

Clastic sedimentary rocks are characterized primarily on the basis of

sediment size

Which of the following characteristics is used to classify and name clastic sediments?

size of the clasts

Mountain streams and rivers typically are characterized by:

steep gradients and are confined by bedrock canyons

Which of the following environments would likely have large clasts?

steep slopes

Which of the following situations would result in angular clasts?

steep slopes on a mountain

In this section, a lower limestone is successively overlain by lagoon mudstone and a beach sandstone. What is the best interpretation of what was going on?

the area was experiencing a regression

Imbricated clasts in this river means that

the current flowed from right to left

Geologists use characteristics such as bedding, mudcracks, and color preserved in sedimentary rocks to determine:

the environment in which the rocks were deposited

Fine-grained sediment would most likely be present at:

the lagoon B and deep seafloor D

Which of the rock layers in this figure was most likely deposited by sand dunes on land?

the lowest red sandstone

Fluvial refers to

the processes and sediment of streams and rivers

What is the main difference between conglomerate and breccia?

the shape of the clasts Conglomerate has larger clasts

Sorting describes

the size range of clasts in sediment

Which of the following processes is NOT considered to be chemical weathering

thermal expansion

What is the best explanation for the shape of these clasts? (very rounded with soft edges)

they have been transported a significant distance

Which of the following environments would most likely have sediment formed by evaporation of seawater?

tidal flat at E

The advance of the sea across a region is known as a

transgression

Downslope marine flows comprised of mixed masses of sand, mud, and water are called

turbidity currents

Which environment is a setting that can deposit sand?

turbidity currents along a continental slope

The natural cements that hold clasts together precipitate in the empty pore spaces after compaction. Those precipitates come from:

water containing dissolved materials

Which of the following attributes apply to these sediments

well sorted

The uniformly-sized sand shown here would be described as

well-sorted