Sedimentary Petrology

Sedimentary Rocks

These rocks cover approximately 75% of the surface.

Sedimentary Rocks

What type of rocks mostly composes the earth surface?

Igneous and Metamorphic Rocks

Under the crust, 95% of the rocks are ________

The most common rock on the surface of the Earth is sedimentary rock. These rocks cover about 75% of the Earth's surface. The surface of the Earth, however, is only a very small part of the crust of the Earth. Under the crust, 95% of the rocks are igneous or metamorphic rocks.

Mass Wasting

The downslope movement of rock, regolith, and soil under the direct influence of gravity

Sedimentum

Means "to settle"

Sediment
Sedimentum
Sedimentary
Sedimentary Rocks

Diagenesis

A collective term for all the changes that take place in texture, composition, and other physical properties after sediments are deposited.

Disintegration
Diagenesis
Lithification
Cementation

Detrital Sedimentary Rocks
Chemical Sedimentary Rocks
Organic Sedimentary Rocks

What are the 3 types of sedimentary rocks?

Detrital Sedimentary Rocks

Rocks formed by the transportation and deposition of sediment and rock fragments.

Chemical Sedimentary Rocks

Are rocks formed when ions of soluble material produced largely by chemical weathering are precipitated by either inorganic or biological processes.

Coal

Black combustible rock consists of organic carbon from the remains
of plants that died and accumulated on the floor of a swamp.

Quartz and Clay Minerals

Are the chief constituents of most sedimentary rocks.

Clay Minerals and Detrital Fragments
Clay Minerals and Organic Materials
Quartz and Micas
Quartz and Clay Minerals

Clay Minerals

When silicates minerals especially feldspars are subjected to chemical weathering their products would be what type of minerals ?

Quartz Grains

What would be the product if Quartz is subjected to extreme chemical weathering?

That the chemical weathering is not extreme which preserved this minerals.

If Feldspars and Micas are present in a sedimentary rock, what does it indicates?

Erosion deposition occurred slow and thus preserving this minerals.

Erosion deposition occurred fast enough to preserve some of the primary mineral.

That the chemical weathering is not extreme which preserved this minerals.

That the chemical weathering is too extreme but these minerals are resistant.

Conglomerate
Breccia
Sandstone
Mudstone (shale)
Siltstone

What are the 5 types of Detrital Sedimentary Rocks?

Particle Size

Detrital Sedimentary Rocks are classified according to which among the following properties?

Texture
Particle Size
Composition
Provenance

Swamp

Which among the following will a rock Shale may form?

Swamp
Shorelines
Flowing River
Alluvial fan

It occurred in a swamp, an oxygen-poor environment where organic materials do not decay.

If a Shale is composed of Carbon, it is usually termed as Black Shale. What does carbon says about the deposition of this rock?

It occurred in a Lagoon where the water is quite.

It occurred in a flowing water where it accumulated carbon particles as it is transported

It occurred in a swamp, an oxygen-poor environment where organic materials do not decay.

Laminae

A nearly parallel alignment of clay and silt particles that is present among sedimentary rocks.

Shale

Rock layers that contain groundwater are commonly underlain this rock bed. It blocks further downward movement of the water and they also prevent oil and gas from escaping to the surface.

Shale

The most abundant
sedimentary rock.

Quartzite
Marble
Shale
Slat
Phyllite
Schist
Gneiss

Fissility

The property of splitting easily into thin layers along closely spaced, parallel surfaces, such as bedding planes in shale.

Siltstone

Another fine-grained sedimentary rock that, like mudstone, is often grouped with shale but lacks fissility. composed largely of silt-size particles and contains less clay-size material than shale and mudstone.

Limestone and Sandstone

Most weathered shales are quite inconspicuous. They crumble easily and usually form as cover of soil that hides the unweathered rock below.

Because of this depositional characteristic of shale it is usually overlain by rocks that form into prominent outcrops and sometimes occur as bold cliffs.

What type of rocks are these?

Limestone

What rock should be mixed with shale in order to make Portland Cement?

Sandstone
Siltstone
Limestone
Mudstone

Portland Cement

If shale and limestone are mixed together what byproduct will they produce?

Sandstone

The name given to rocks in which sand-size grains predominate

Graywacke

Dirty, immature Sandstone

Quartz Sandstone

Mature Sandstone

Arkose

Feldspar dominated Sandstone

Sorting

Refers to the degree of similarity in particle size in a sedimentary rock.

Well Sorted

If all the grains in a sample of sandstone are about the same size

Poorly Sorted

If the rock contains mixed large and small particles

The grains were transported through water such as streams or by wind.

The shape of sand grains can tell more about the history of a sandstone.

What would be the mode of transport if the shape is rounded?

The grains were carried by a medium such as glacier

The grains were transported through water such as streams or by wind.

The grains were transported by the action of gravity through falling

Angular Grains

What degree of rounding would you expect if the transporting agent is Glaciers rather than Rivers?

Rounded Grains
Angular Grains
Oblate Grains
Equant Grains

Mode of Transport

The origin and history of sandstone can often be deduced by examining some criteria. Which among the following criteria does not belong?

Mineral composition
Quality of Sorting
Mode of Transport
Degree of Rounding

Arkose

When a sandstone contains appreciable quantities of feldspar (25 percent or more), the rock is called ________

Arkose/Arkosic Sandstone

A sandstone with 25% feldspar

Granite

The mineral composition of an Arkose or Arkosic Sandstone such that Qtz+mica+feldspars indicates that the grains were derived from what rock source?

Rhyolite
Granite
Granodiorite
Diorite

Granite

The parent rock of arkose is

Rhyolite
Granite
Andesite
Diorite

Greywacke

A dark coarse-grained sandstone containing more than 15 percent clay.

Greywacke

A dark sandstone with 15% clay matrix

Conglomerate

Consist largely of rounded gravels, poorly sorted, and the spaces between particles contain sand or mud.

Breccia

If the large particles are angular rather than rounded, the rock is called _______.

Inorganic

A chemical process such as evaporation and chemical activity is considered as

Organic
Inorganic

Organic

When water-dwelling organisms form chemical sediments that is said to be of biochemical origin

Organic
Inorganic

Reefs

Consist of coral colonies made up of great numbers of individuals that live side by side on a calcite structure secreted by the animals.

Australia's Great Barrier Reef

The best-known modern reef

Coquina

A coarse rock composed of
poorly cemented shells and shell fragments

Chalk

A soft, porous rock made up almost entirely of the hard parts of microscopic marine organisms.

White Chalk Cliffs of Dover England

Is a massive biochemical limestone(Chalk Cliff) made up almost entirely of the tiny hard parts of microscopic marine organisms, mainly plankton located it Dover, England

Inorganic Limestones

Limestones that form when chemical changes or high water temperatures cause calcium carbonate to precipitate out of the water.

Dolostone/Dolomite

A fine-grained sedimentary rock composed primarily of dolomite, a calcium and magnesium carbonate mineral.

Dolomitization

The process by which the magnesium-rich waters circulate through a limestone and replaces calcium ions with magnesium ions.

Chert

A hard, compact, fine-grained sedimentary rock formed almost entirely of silica.

Chert

A rock composed of 100% Silica

Chert

The name applied to a number of dense, hard chemical sedimentary rocks made of microcrystalline quartz.

Flint

a very hard stone that produces a spark

Flint

The black colored variety of chert. The color results from the organic matter it contains.

Jasper

A red variety of chert, gets its bright color from iron oxide.

Petrified Wood

A chert that is made when silica-rich material such as volcanic ash buries trees.

Iron Oxides

The mist important pigments

Bedded Cherts

Are cherts believed to originate from tiny marine organisms (diatoms and radiolarians) that produce hard parts from silica rather than calcium carbonate. Some occur in association with lava flows and layers of volcanic ash. For these occurrences, it is probable that the silica was derived from the decomposition of the volcanic ash.


Bedded Cherts
Chert Nodules

Chert Nodules

Are rounded masses of charts that sometimes referred to as secondary cherts, or replacement cherts. They form when silica, originally deposited in one place, dissolves, migrates, and then chemically precipitates else- where, replacing older material.


Bedded Cherts
Chert Nodules

Halite

What is the chief component of rock salt?

Sylvite
Halite
Sphalarite
Anhydrite

Bonneville Salt Flats

Salt flats in Utah

Coal

a combustible black or dark brown rock consisting mainly of carbonized plant matter, found mainly in underground deposits and widely used as fuel.

Coal

A sedimentary rock that burns

80%

Gypsum precipitates when about what percent of the seawater has evaporated?

60%
70%
80%
90%

90%

How much water should be removed for mineral Halite to eventually precipitate?

60%
70%
80%
90%

Sylvite

Last formed salt

Gypsum
Halide
Sylvite
Anhydrite

Swamp

a lowland region that is saturated by water. An important environment for the build up of plant material.

Oxygen

What element of the earth is deficient in a swamp environment?

Nitrogen
Oxygen
Carbon Dioxide
Carbon Monoxide

Peat

A soft, crumbly and dark brown material formed by the partial decomposition of organic matter, primarily plant material, in wetlands.

Lithification

What process promotes diagenesis?

Cementation
Lithification
Diagenesis
Necrolysis

Metamorphism

Diagenesis occurs within the upper few kilometers of Earth's crust, at temperatures that are generally less than 150° to 200°C (300° to 400°F). Beyond this somewhat arbitrary temperature threshold, what process is said to occur.

Cementation
Compaction
Lithification
Metamorphism

None of the above

Which among the following is not an example of diagenesis?

Recrystallization
Compaction
Lithification
Cementation
None of the above

Lithification

The processes by which unconsolidated sediments are transformed into solid sedimentary rocks

Recrystallization
Compaction
Lithification
Cementation

Compaction and Cementation

What are the two main processes that contributes to Lithification?

Compaction

As sediment accumulates, the weight of overlying material compresses the deeper sediments. The deeper a sediment is buried, the firmer it becomes.

Recrystallization
Compaction
Lithification
Cementation

Compaction

A reduction in pore space by packing grains more tightly together

Recrystallization
Compaction
Lithification
Cementation

Cementation

A reduction in pore space by adding new mineral material that acts as a "glue" to bind the grains to each other.


Recrystallization
Compaction
Lithification
Cementation

Cementation

A process in which ions carried in solution by groundwater crystallize in the spaces between sediment grains to form minerals that gradually cement the grains together.

Recrystallization
Compaction
Lithification
Cementation

Calcite
Silica
Iron Oxide

What are the most common cements in a sedimentary rock?

Calcite Cement

A cementing material that effervescence in contact with dilute hydrochloric acid.

Calcite Cement
Silica Cement
Iron Oxide Cement

Silica Cement

Refers to the hardest cement and thus produces the hardest sedimentary rocks.

Calcite Cement
Silica Cement
Iron Oxide Cement

That the rock is composed of Iron Oxide

Choose the best answer.

If a sedimentary rock has an orange or dark red color, what does it imply?

That the rock has undergone diagenesis

That the rock is composed of Iron Oxide

That the rock has oxidized

That the rock is cemented

Clastic

All detrital rocks have _______ texture

Clastic
Non-clastic

Clastic

Means "broken"

Clastic Sedimentary Rocks

Sedimentary rocks that consist of discrete fragments and particles that are cemented and compacted together.

Nonclastic Sedimentary Rocks

Sedimentary rocks in which the minerals form a pattern of interlocking crystals. The crystals may be microscopically small or large enough to be visible without magnification.

Nonclastic Sedimentary

These types of Sedimentary Rocks may resemble Igneous Rocks

Sedimentary Rocks

What rocks represent past environments?

Igneous Rocks
Sedimentary Rocks
Metamorphic Rocks

Sedimentary Enviroenment
Environment of Deposition

A geographic setting where sediment accumulates. Each site is characterized by a particular combination of geologic processes and environmental conditions.

Oceanic

Which among the following is not a part of the 3 broad categories of sedimentary environments?

Continental
Oceanic
Marine
Transitional

Marine
Continental
Transitional (Shoreline)

What are the 3 categories of Sedimentary Environments?

Facies

The physical, chemical, and biological aspects of a sedimentary bed and the lateral change within sequences of beds of the same geologic age.


Beds
Planes
Facies
Layerings

Sedimentary Facies

A series of sedimentary layers, where you can observe successive changes in environmental conditions that occurred at a particular place with the passage of time.

Sedimentary Facies

Are lateral equivalents that represent different depositional conditions operating in adjacent areas at the same time.