Geology - chapter 7; exam 3

Sediments

-Bits & pieces of rocks -Driving force/movement: Erosion -Moved by water, wind, biological activity (us), Glaciers/ice. -Change in energy causes movement to STOP.

____ is a biochemical sedimentary rock that often forms in carbonate reefs. *Bituminous Coal *Limestone *Chert *Rock Salt

**Limestone

Which of the following mudstones displays fissility? *Shale *Siltstone *Slaystone

**Shale

____ describes the range in particle sizes in a detrital sedimentary rock. *Size *Cementation *Sorting *Shape

**Sorting

A _____ describes how, when a sedimentary layer is examined in cross-section laterally, various parts of the layer consist of different sediments accumulating next to each other in different environments of deposition. *Delta *Transitional Environment *Facies *Turbidity Current

Facies

Compaction

LITHIFICATION -As sediments are buried, the weight of the overlying material compresses the deeper sediments

Detrital sedimentary rocks are classified according to class size whereas chemical sedimentary rock are classified based on their dominant minerals. *True *False

True

The formation of sedimentary rock requires _____. *The melting of pre-existing rocks *Weathering & erosion of pre-existing rocks *Weathering of pre-existing rocks *The application of heat & pressure to pre-existing rocks *Erosion of pre-existing rocks

Weathering & Erosion of pre-existing rocks

Conglomerate Rocks

-Consists of rounded, gravel-sized sediments. -poorly sorted. -high energy to move

Breccia Rocks

-Consists of Angular, gravel-sized sediments. -poorly sorted. -high energy to move.

Diagenesis

-Chemical, physical, & biological changes that take place after sediments are deposited & buried. -Occurs within the upper crust -Turning Sediments into Sedimentary rock

Chert

-Composed of microcrystalline quartz -Forms when dissolved silica precipitates; & USES WATER. -Ex: Flint, Jasper; petrified wood.

Sedimentary Rocks

-Cover 75% of Earth & comprise 5% (volume) of Earth's outer 10 miles. -Evidence of past environments: Coal = swamp area. -An important resource rocks: coal, oil, fossil fuels, & groundwater resources. -IMPORTANT B/C WE FIND FOSSILS IN THEM! -Products of mechanical & chemical weathering -Three types: Detrital, Chemical, & Organic. -Classified according to the type of material: Detrital & Chemical/Organic.

Chemical Sedimentary Rocks

-Form from precipitated material that was once in a water solution. -ALL IN WATER ENVIRONMENTS; minerals that are dissolved in water & sediments are changed from water. -Inorganic processes, such as water evaporating. -Organic processes from water-dwelling organisms (Ex: oyster shell) -Types: Limestone, Chert, Evaporites,

Detrital Sedimentary Rocks

-Form from sediments that have been weathered & transported. -Go through Lithification -Types: Shale Sandstone, Conglomerate, & Breccia

Organic Sedimentary Rocks

-Form from the carbon-rich remains of organisms -Plant structures (leaves, bark, & wood) are identifiable in coal.

Evaporites

-Form when restricted seaways become over-saturated & deposition begins. -Ex: SALT -Form salt flats when dissolved materials are precipitated as a white crust on the ground

Inorganic Limestone

-Forms when chemical changes cause calcium carbonate (calcite) to precipitate. -Seen more on continents; land masses. (ex: Caves) -Travertine & Oolitic Limestone.

Shale

-Most common Detrital Rock -Silt & clay sized particles, may be soft & crumbly, abundant; fine-grained. -Has Fissility. -Environment: Calm & quiet. (Ex: offshore from beach w/ no wave activity.

Sandstone

-Sand-sized particles, abundant. -Forms in a variety of environments (ex: beaches). -Quartz is the most common mineral. -Particles vary & are classified by their sorting & shape. -Rounded vs. Angular: how far the sediments have been transported; RELATED TO AGE.

Sorting

-The degree of similarity in particle size in a sedimentary rock. -if grains in rock are similar size; gradual change in environment; has a better porosity (open space): Well. -If grain in rock are different sizes (both large & small); quick change in environment; lower porosity (close spaces): poorly.

Fissility

-The rock can be split into thin layers. -Clay & mud.

Lithification

-Unconsolidated sediments are transformed into sedimentary rocks. -How the sediments turn into sedimentary rocks; rock forming process -Need Compaction to push sediments together & need Cementation to glue together & make stick (WATER).

Limestone

-most common chemical sedimentary rock. -10% of all sedimentary rock -uses: cement, asphalt concrete, toothpaste, etc. -Biochemical: coral reefs: Great Barrier Reef is the largest on Earth. -Inorganic: Caves. -WATER WATER WATER

Angular Sediments

-only transported a short distance -lower porosity, close spaces. -shorter time in erosion phase.

Biochemical Limestone

-originates from the shells of marine organisms. -Seen more in the ocean. -Ex: Chalk, Coquina.

Rounded Sediments

-typically transported great distances. -more open spaces; higher porosity. -longer time in erosion phase; moving for awhile.

Which of the following agents is capable of moving sediment from the site of formation to the site of deposition? *Wind *Running Water *Waves *Ice *All of the answers are correct.

All of the answers are correct.

True

Approximately 75% of the planet's landmasses are covered by sedimentary & sedimentary rocks

A _____ marks the end of one episode of sedimentation and the beginning of another. *Bedding plane *Cross-bedding *Graded beds *Ripplemark

Bedding Plane

What coal is soft, black in color, & produces soot upon handling? *Low-grade *Anthracite *Peat *Lignite *Bituminous

Bituminous

Detrital

CLASSIFICATION OF SEDIMENTARY ROCKS -Has clastic texture, composed of discrete fragments cemented together. -Ex: sandstone, shale, conglomerate.

Chemical/Organic

CLASSIFICATION OF SEDIMENTARY ROCKS -Has nonelastic or crystalline texture, where the minerals form patterns of interlocked crystals. -Ex: Salt, cave limestone.

What type of detail sedimentary rock forms from sediment transported & deposited by energetic mountain streams? *Shale *Sandstone *Conglomerate *Mudstone

Conglomerate

During the process that forms sedimentary rocks, how does compaction affect sediment? *It decreases the volume of pore spaces *It decreases the size of interlocking crystals *It decreases the amount of calcite in the sediment *It changes the shape of sand grains.

It decreases the volume of pore spaces

Why is coal different from other sedimentary rocks? *It forms in a marine environment *It is made of almost entirely of organic matter. *It is a valuable economic resource *It forms from pieces of igneous rocks.

It is made of almost entirely of organic matter

Cementation

LITHIFICATION -Involved the crystallization of minerals among the individual sediment grains.

Abundant plant material accumulating in a swampy environment w/ _____ is required for peat to form. *Metamorphism *High oxygen levels *Organisms *Low oxygen levels *Sand deposition.

Low Oxygen Levels

How is anthracite produced from bituminous coal? *Increased plant material *Energy from sunlight *High biologic activity *Metamorphism *The presence of water

Metamorphism

Coal

ORGANIC SEDIMENTARY ROCKS -Accumulation of plants (carbon) in an oxygen-poor environment: SWAMP, little decomposition.

Name the progression of coal types with increased heat & pressure from burial. *Peat, lignite, anthracite, bituminous *Peat, lignite, bituminous, anthracite *Lignite, bituminous, anthracite

Peat, Lignite, Bituminous, Anthracite

Which is an example of a sedimentary rock composed of solid masses of inter grown crystals? *Sandstone *Shale *Conglomerate *Rock Salt *Basalt.

Rock Salt

Which of the following makes up the sediment that forms an organic sedimentary rock? *Weathered ions *Shells & Plant Fibers *Gravel & Sand *Dissolved Minerals.

Shells & Plant Fibers

You find a sedimentary rock that has all its flat particles aligned in parallel. From this you can infer that ___. *The particles have been cemented *There are no fossils in the rock *The particles have been compacted *There is no quartz in the rock *The particles have been melted.

The particles have been compacted

Chemical sedimentary rocks form from ____. *The compaction of sediments *Compacted ash from volcanoes *Compacted pieces of decaying plant material *The precipitation of ions in solution

The precipitation of ions in solutions (use definition from PP)

*On the surface of continents *On the ocean floors

Where are most sediments & sedimentary rocks found? CHOOSE ALL THAT APPLY. *On the surface of continents *At mid-ocean ridges *In the mantle *At the base of Earth's crust *On the ocean floor