Chapter 7: Sedimentary Environments and Rocks

Choose the calm-water environments where silt and clay tend to accumulate. (Choose all that apply.) -Steep continental slopes -Mud flats -Ocean bottom -Lagoons -Beaches

-Mud flats -Ocean bottoms -Lagoons

Most of the material contained within nonclastic sedimentary rocks consists of _______. (Choose all that apply.) -minerals precipitated from solution as water evaporates -materials formed through biological activity such as making shells or other hard parts -compacted clay particles -eroded and transported pebbles and cobbles

-minerals precipitated from solution as water evaporates -materials formed through biological activity such as making shells or other hard parts

Compaction causes sediments to become _______. (Choose all that apply.) -more compact -less dense -more dense -more porous

-more compact -more dense

A sandstone with a history that can be traced to beach deposits will likely include sand and ______. (Choose all that apply.) -pebbles and larger clasts -finely layered clay -pieces of shells -finely layered silt

-pebbles and larger clasts -pieces of shells

Sedimentary environments on land differ because of variations in _______. (Choose all that apply.) -topography -gravity -local geography -amount of water -oxygen isotope ratios

-topography -local geology -amount of water

Place in correct vertical order (as you would see them in a stratigraphic section) the sedimentary facies created during a sea regression. -Beach sandstone -Limestone -Mud

1. Beach sandstone 2. Mud 3. Limestone

Place in correct order the sedimentary facies created during a sea transgression. Put the layer as you would see them in cross section, with the layer formed first on the bottom and the youngest layer on top. -Sandstone -Limestone -Bedrock w/ erosional surface -Mudstone

1. Limestone 2. Mudstone 3. Sandstone 4. Bedrock w/ erosional surface

What is a carbonate rock?

A carbonate rock is a sedimentary rock that consists of carbonate ions bonded to other elements.

Breccia and conglomerate are the coarsest types of clastic sedimentary rocks. Match the rock type to the shape of clast. Breccia --- Rounded clasts Conglomerate --- Angular clasts

Breccia = Angular clasts Conglomerate = Rounded clasts

________ begins after sediment is buried. Pressure pushed clasts together and forces out excess water.

Compaction

Match both conglomerate and breccia to the depositional environments in which they would most likely form. *Conglomerate OR Breccia -river -beach -alluvial fan -rock slide deposit

Conglomerate: -river -beach Breccia: -alluvial fan -rock slide deposit

Match the environmental depositional shift to its correct description. *Transgression OR Regression -Facies shift toward land -Facies shift away from land -The sea moves out -The sea moves in

Transgression: -Facies shift toward land -The sea moves inland Regression -Facies shift away from land -The sea moves out

The rounded clasts in this sedimentary deposit were likely transported _______, and were rounded by a rolling action during this transport.

by a river

Glaciers cause massive amounts of ______ of the underlying material, thereby producing a lot of sediment.

erosion

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

fine grained (smaller than sand)

Because shales and siltstones are easily eroded, the areas where they are exposed typically _________.

have soft slopes and soil cover

The typical large clasts found in breccia indicate that energy levels of the transporting agent were ______.

high

Limestone is formed _______ by organisms such as coral that extract calcium carbonate from the water to form their shells and skeletons. (Choose all that apply.)

in reefs, oceans, & seawater

The four main types of natural cement include ______.

iron oxides, silica, calcite, & clay minerals

Travertine is a type of _____ that forms through precipitation in springs, lakes, and caves.

limestone

Sandstone is defined by being mostly or wholly composed of _____-sized grains. (Hint: We are not looking for a number here, but a term.)

sand

Sandstone is common because ________.

sand occurs in many environments (Sandstone can be deposited in many settings such as lake beds or riverbeds, marine environments, or sand dunes.)

Sandstone, conglomerate, and shale are types of common clastic _____ rocks.

sedimentary

Fluvial refers to:

the processes and sediments or streams and rivers.

Turbulent, underwater masses of flowing sand, mud, and water are called ___________ currents.

turbidity

Which of the following processes would be most likely to form the well-rounded clasts found in a conglomerate rock sample? (Select all that apply.) -Mineral growth in situ (in place) along smaller angular clasts -A short distance of transport -A long distance of transport -Glacial plucking and transport -Wave action along a beach

-A long distance of transport -Wave action along a beach

Match the attribute found in sedimentary rocks to the type of information it provides. -Bed thickness -Color -Clast size -Fossils -Cross beds -Direction of wind or water current -Distance of transportation -Formed on land or in the water -Small or large depositional events -Formed on land or in the water, and type of climate

-Bed thickness = Small or large depositional events -Color = Formed on land or in the water -Clast size = Distance of transportation -Fossils = Formed on land or in the water, and type of climate -Cross beds = Direction of wind or water current

Match the rock with its environment of deposition. (Picture on pg. 197) -C -- shale and limestone -A -- red sandstone -B -- tan sandstone w/ shells -D -- breccia -mountainous area -shallow sea -beach sand -large sand dune

-C -- shale and limestone = shallow sea -A -- red sandstone = large sand dune -B -- tan sandstone w/ shells = beach sand -D -- breccia = mountainous area

Match the sedimentary rock name with the description that is the best fit. -Conglomerate -Breccia -Sandstone -Siltstone -Shale -Sand-sized particles of varying mineral content -Silt-sized particles, mostly containing quartz -Very fine-grained clay minerals -Angular pebbles and cobbles with sand and finer particles between the larger clasts -Rounded pebbles and cobbles with sand and finer particles between the larger clasts

-Conglomerate = Rounded pebbles and cobbles with sand and finer particles between the larger clasts -Breccia = Angular pebbles and cobbles with sand and finer particles between the larger clasts -Sandstone = Sand-sized particles of varying mineral content -Siltstone = Silt-sized particles, mostly containing quartz -Shale = Very fine-grained clay minerals

What are the three types of beds formed by sedimentary layers? -Lifted -Concave -Scoured -Cross -Parallel -Graded

-Cross -Parallel -Graded

Match the nearshore or ocean sedimentary environments to its description. -Deep seafloor -Lagoons -Tidal flats -Barrier islands -Dominated by fine dust of windblown origin and the remains of single-celled organisms -Low areas alternately covered by water and exposed to the air -Long, narrow accumulation of sand located parallel and near to the shoreline -Mixed sand and mud of fluvial origin derived from land and coral and sand from reefs

-Deep seafloor = Dominated by fine dust of windblown origin and the remains of single-celled organisms -Lagoons = Mixed sand and mud of fluvial origin derived from land and coral and sand from reefs -Tidal flats = Low areas alternately covered by water and exposed to the air -Barrier islands = Long, narrow accumulation of sand located parallel and near to the shoreline

Layering in sedimentary rocks can have many causes. These layers are known as beds or bedding. List all the possible causes of bedding.

-Discrete events -Change in sediment supply -Change in sea level -Change in climate -Change in currents

Choose the statements that correctly describe limestone. (Check all that apply.) -Is known as a carbonate -Gray or yellowish in color -Forms in water from various processes -Is a clastic sedimentary rock -Commonly includes shells

-Is known as a carbonate -Gray or yellowish in color -Forms in water from various processes -Commonly includes shells

Match the sedimentary environment to the description that best fits it. -Mountain -Dry climates -Delta -Wet environments -Soil saturated by water with vegetation adding to the available sediment -Wind moving sand and fine particles and forming large sand dunes -Formed by sediment piling up where a river enters a standing body of water -Steep gradients, vigorous erosions, and fluvial systems confined by bedrock

-Mountain = Steep gradients, vigorous erosion, and fluvial systems confined by bedrock -Dry climates = Wind moving sand and fine particles and forming large sand dunes -Delta = Formed by sediment piling up where a river enters a standing body of water -Wet environments = Soil saturated by water with vegetation adding to the available sediment

Match the nonclastic sedimentary rock w/ the process by which it typically forms. -Rock salt and gypsum -Dolostone -Chert and iron-rich formations -evaporation -precipitation -chemical replacement

-Rock salt and gypsum = evaporation -Dolostone = chemical replacement -Chert and iron-rich formations = precipitation

Which of these rock types are clastic sedimentary rocks? -Sandstone -Gneiss -Conglomerate -Shale -Limestone -Marble -Obsidian

-Sandstone -Conglomerate -Shale

Match the predominant sediment size to its rock type. -Silt --- Siltstone -Clay --- Mudstone -Silt mixed w/ clay --- Shale

-Silt = Siltstone -Clay = Shale -Silt mixed w/ clay = Mudstone

Sedimentary layers do not go on and on laterally, but eventually pinch out or end. Which of the following are the two reasons why these layers do end? -Sedimentary layers are limited in extent to a few tens of kilometers. -The layers were deposited within a channel. -The facies they represent have a limited extent. -Sedimentary layers are formed only in water, which does not cover al of Earth's surface.

-The layers were deposited within a channel. -The facies they represent have a limited extent.

Almost all sedimentary rocks contain layers. Those layers can be best described by which of the following statements?(Check all that apply.) -Must have well-defined boundaries -Vary in how well boundaries are defined -Vary in thickness -Vary in lateral continuity -Must have a rather uniform thickness

-Vary in how well boundaries are defined -Vary in thickness -Vary in lateral continuity

Turbidity current deposits ________.

-are interbedded w/ dark shales -often have graded beds

Which of the following best describes the way(s) in which limestone can form? -A combination of biological and inorganic processes -Magnesium replacing calcite via dissolution -Inorganic processes -Compaction and cementation of mainly quartz sand

A combination of biological and inorganic processes

The cross beds shown here indicate what about the environment the sandstone was deposited in?

Water/wind flowed from right to left.

A formation is defined as ________.

a rock that is distinct and laterally traceable

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

Melting glaciers tend to deposit most of the sediment they carry and create _______.

at their terminus (end)

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

barrier islands

Symmetrical ripple marks are common structures preserved in _____ sand, and can indicate the general direction of wave action.

beach

Nonclastic sedimentary rocks formed by both biological and chemical process are known as ______ rocks.

biochemical

The pore space that remains after sediment compaction is often filled by the precipitation of minerals from fluid. These minerals (materials) act as a natural ________ that binds clasts together.

cement

The vast ocean seafloor is covered with ______-sized sediments more than any other size deposit. This is the primary reason that shale is a very common sedimentary rock.

clay

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

This type of carbonate rock is formed when magnesium replaces calcium in limestone to form a different mineral.

dolostone

In ______ climates, wind can move fine particles and may form sand dunes that stretch hundreds of kilometers.

dry

Carbonate rocks found in ______ environments are commonly massive, gray in color, and are erosion-resistant, whereas carbonate rocks found in _______ environments are often pitted, holey, and very fractured.

dry, wet

Limestone that forms in continental environments is created through _____ in arid environments and through _______ in spring and caves.

evaporation, precipitation

The term _____ is used to describe a sedimentary deposit or rock type that reflects a specific environment, such as a beach or delta.

facies

A rock unit that is distinct and laterally traceable is called a(n) _______.

formation

A(n) ________ is formed by the sheltering of nearshore water from wave action by a reef or islands. The sheltered water is commonly shallow, quiet, and perhaps warm.

lagoon

Clay and silt-sized particles tend to be deposited in areas of _______ energy.

low

Lime muds and clastic limestone sands are deposits that formed carbonate rocks in ______ environments.

nearshore

The accumulation or plant material, usually in a swampy environment, leads to the formation of _______. If the material is heated, compacted, and buried it can become coal.

peat

The most likely cause of graded bedding found in sedimentary rocks is _________.

reduction in water current velocity

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

reefs

A(n) ________ occurs when the sea retreats because sea level drops and/or land is uplifted.

regression

Different environments tend to produce sandstones that ________.

reveal clues about their different origins

The characteristics of marine environments depend mainly on the proximity to shore, the availability of _______, and the depth, temperature, and clarity or the ________.

sediment, water

Geologists use _____ rocks to determine past environments of deposition on Earth's surface. These types of rocks preserve a variety of characteristics that might suggest temperature, elevation, geographic location, and changes in climate.

sedimentary

Mudstone and shale are not split into two rock types by some geologists. Geologists that do classify them differently do so because mudstone has more ______ than the typical shale.

silt

Loose debris on a rock-exposed landscape in known as _________.

talus

The pieces of rock that collect at the bottom of steep slopes are known as _________.

talus

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

transgression