smart work chapter 6-8

what are the characteristics of biochemical limestone?

- made of calcite - forms from coccolithophores and formaninifera, as well as shells from larger organisms - reacts with dilute acid

what happens when transgression occurs at a given location

- sea levels rise - mud layer accumulates over a sand layer - the coastline migrates inland

Which factors control the cooling time of magma within the crust?

- the depth at which the magma cools - the volume of the intruded magma

Phaneritic Rock Texture

-Coarse-grained igneous rocks -Mineral grains are large enough to see with the naked eye

what happens during transgression?

-coastline migrates inland - position of beach moves inland - involves a relative rise in sea level - mud layer accumulates over a sand layer

what is extreme shear

-contrasting rock types are smeared into parallel layers

what are characteristics of biochemical chert?

-forms of radiora and diatoms -does not react with dilute acid -made of quartz (cryptocrystalline)

what composition of magma is produced by melting at lower temperatures? at higher temperatures?

1. felsic 2. intermediate 3. mafic 4. ultramafic

what are the steps in fractional crystallization?

1. magma, afters entering through the bottom of the magma chamber, reaches the top of the chamber 2. magnesium - and iron -rich minerals begin to crystallize 3. minerals crystals, having a higher density than liquid magma, sink to the bottom of the magma chamber 4. the magma shifts toward a more intermediate composition.

Crystalline igneous rocks are distinguished from each other by grain size. Sort the rock names into the appropriate grain-size category. granite, bassalt andesite

coarse grained: granite Fine-grain: andesite and basalt

order of sedimentary rock from coarse to fine grained . conglomerate, shale/mudstone, sandstone, and siltstone

coarsest: 1. conglomerate/breccia 2. sandstone 3. siltstone 4. shale/mudstone finest:

what is the difference between a conglomerate and a breccia?

conglomerate has rounded grains, and a breccia has angular grains

Choose the most likely product of partially melting a rock of intermediate composition. Choose one: A. ultra-mafic magma B. mafic magma C. felsic magma D. a melt of the same composition as the original rock

felsic magma

what are hornfels

fine-grained, can have multiple minerals, non-foliated, and minerals depend on temperature, pressure, and protolith composition

What does subduction of an oceanic plate, triggers what?

flux melting

what is differentiation

chemical reactions cause felsic and mafic minerals to grow in distinct separate layers

what type of rock is granite?

felsic - high proportions of grey, white, pink)

what is the relationship between the velocity of a fluid and the size of the sediment that the fluid carries?

the faster a fluid flows, the larger the clasts it can carry

metamorphism can transform a shal composed of clay into metamorphic rock contianing many different minerals. the metamorphism of a ppure quartz sandstone, however, yeilds a metamorphic rock containing only quartz. Why is that the case?

the sandstone is made up only of quartz (silicon and oxygen), and there are no other combinations these elements can be arranged into except polymorphs

What is recrystallization?

the shape of the grains change without changing the identity of the mineral

What is decompression melting?

the upward movement of the earth's mantle to an area of lower pressure

what is the geologic process necessary to form sedimentary rock from beginning to end.

1. rock is weathered to produce sediments 2. sediments are buried 3. compaction removes air from pore spaces 4. chemically rich groundwater flows through pore spaces 5. minerals precipitate in pore spaces 6. sediments are glued together by cement to form sedimentary rock

what is the minimum temperature metamorphism can occur?

250

Shale

A sedimentary rock formed by the deposition of successive layers of clay.

metamorphic facies

A set of metamorphic mineral assemblages indicative of metamorphism under a specific range of pressures and temperatures.

dike

A slab of volcanic rock formed when magma forces itself across rock layers

What is meant by the term metamorphic grade? Choose one: A. the intensity of metamorphism B. the resistance of a rock to metamorphic processes C. the length of time it takes for a rock to metamorphose D. the clarity of mineral grains in metamorphic rocks

A. intensity of metamorphism

porphyritic texture

An igneous rock texture in which large crystals are scattered on a background of much smaller crystals.

Identify the statement that best describes the role of magma mixing in altering magma composition. Choose one: A. It is thought that magma mixing takes place readily and affects the majority of magma chambers. B. It is thought that separate magma chambers can undergo mixing via the creation of connections between the two chambers C. Magma mixing is the primary process in the genesis of new magma compositions. D. It is now known that magma mixing is not a plausible means of altering magma compositions.

B. It is thought that separate magma chambers can undergo mixing via the creation of connections between the two chambers

what are the descriptions of the composition of sedimentary rock, ad what are those characteristics?

Argillaceous: made of mostly clay minerals Silceous: made mostly of quartz Carbonate: made mostly of calcite and or dolomite

Using the phase diagram shown below, determine which statement best describes what happens as a rock is moved from point A to point B.

As a rock is moved up in the Earth, it is subjected to slightly lower temperatures and much lower pressures, and it begins to melt.

how do evaporites form? Choose one:A. They form as salt is deposited on the slopes of a mountain.B. They form when a body of water is evaporated and re-precipitated in a different location.C. They form as ions (minerals) precipitate out of an evaporating solution.D. They form as silica is evaporated out of seawater.

C. They form as ions (minerals) precipitate out of an evaporating solution.

Choose the statement that best describes foliation. Choose one: A. the texture typical of all metamorphic rocks B. an arrangement of mineral grains such that most are of the same size and shape C. an alignment of mineral grains perpendicular to the direction of compression D. an alignment of mineral grains parallel to the direction of compression

C. an alignment of mineral grains perpendicular to the direction of compression

Biochemical sedimentary rocks are composed of the shells of dead organisms, but organic sedimentary rocks are composed of __________. A. living organisms B. bones of dead organisms C. organic material/compounds of dead organisms D. tracks and burrows of dead organisms

C. organic material/ compounds of dead organisms

Why are there so many different types of magma?

C.Different magmas may mix to form a new magma. D.The source rock from which magmas form may differ.

what are the four major classes of sedimentary rock and what do they consist of?

Clastic: solid fragments and grains broken off of pre-existing rocks that are cemented together Biochemical: consists of shells grown by organisms Chemical: consists of minerals precipitated from surface-water solutions Organic: carbon-rich remains of or other organisms

vescular

Gas pockets

what does the addition of heat cause metamorphic reactions to take place? Choose one:A. Heat slows down the vibration of atoms, allowing them to break their bonds more easily and create new minerals.B. Heat causes the rock to behave like dough, which can be easily shaped into new minerals and textures.C. Heat melts the rocks to eventually create new minerals.D. Heat causes atoms in minerals to vibrate rapidly, causing chemical bonds to break and form new ones with other atoms.

D. Heat causes atoms in minerals to vibrate rapidly, causing chemical bonds to break and form new ones with other atoms.

Does a low-grade metamorphic rock have all the same minerals as a high-grade rock if they both form from the same protolith?Choose one: A. No, because protoliths have slight differences in composition that affect neocrystallization and recrystallization. B. Yes, but the minerals are larger in high-grade rocks due to recrystallization. C. Yes, because metamorphic processes do not alter the minerals found in rocks .D. No, because neocrystallization produces new mineral assemblages that are stable at higher temperatures and pressures.

D. No, because neocrystallization produces new mineral assemblages that are stable at higher temperatures and pressures.

What does granite look like?

Granite is grey, speckled, with flecks of sparkles and it's made up of ,mica, quartz and feldopar

Aphanitic Rocks

Have no visible crystals, and probably formed by fast cooling above ground.

what are pyroclastic debris?

It is cooled fragments of magma/lava

What does grain size generally indicate about the cooling of a melt? A. Larger crystals indicate the melt cooled gradually. B. Larger crystals indicate the melt cooled at a shallower depth. C. Larger crystals indicate the melt cooled rapidly. D. Larger crystals indicate the melt cooled at a deeper depth.

Larger crystals indicate the melt cooled gradually.

what are the different sandstones and there characteristics ?

Quartz: quartz grains only Arkose: quartz and feldspar Lithic: sand-sized rock fragments Wacke: sand and rock fragments in a clay-rich matrix

what is foliation

Roughly parallel layers of mineral crystals aligned perpendicular to the direction of pressure

fossiliferous limestone

Sedimentary, A rock: sedimentary, composed of calcite with various size shells cemented with calcite cement.

sill

a slab of volcanic rock formed when magma squeezes between layers of rock

What does Scoria look like?

abundant presence of vesicles

Identify the factors that cause melting and thus the formation of magma.

addition of volatiles, decompression, heat transfer

_______deposits are wedge-shaped deposits consisting of coarse sediments and a large amount of feldspar, typically at the foot of an eroding mountain range, whereas __________deposits consist mostly of clay and the skeletons of planktonic microorganisms.

alluvial-fan; deep marine

alluvial fan

are composed of coarse sediment deposited when a mountain stream spills into an unconfined area

if a sedimentary rock precipitates from water solution, is it clastic, biochemical, organic or chemical

chemical

Magma rises because it's_________ and because pressure due to the weight of overlying rocks squeezes it upward. Volatile content, silica content, and temperature are factors that affect_________of magma.

buoyant, viscosity

where does travertine come from?

caves and near hot springs

what processes take place during lithification?

cementation and compaction

What is dynamothermal metamorphism?

consequence of developing mountain ranges, large slices of continental crust slip up and over portions of the crust, the resulting rock that was once near the Earth's surface along the margin of the continent ends up at depth beneath the mountain range. In this new environment, 3 changes occur: the protolith heats up due to the geothermal gradient and igneous activity, the protolith is subjected to greater pressure due to overburden, and the protolith undergoes squashing and shearing because of differential stress generated by plate interaction.

cover vs. basement: layers of sedimentary rocks, called, beds from_____ that buries the underlying ______ of igneous and/ or metamorphic rock

cover, basement

what does xenolith look like?

dark, elliptical, mafic

A metamorphic rock with minerals aligned in a preferred orientation or has alternating dark-colored and light-colored layers is said to have________

foliation

__________ is a phenomenon that influences the composition of a magma by removing iron and magnesium so that the remaining magma is more felsic.

fractional

how does salt and other evaporites deposits form in association with restricted bodies of water?

from the open ocean, over to restricted basin, from there new salt accumulates and water evaporates and near the desert.

what happens during regression

has a relative fall in sea level

what is a common characteristic of a metamorphic rock?

has elongated grains that are oriented in the same direction

When very hot magma from the mantle rises to meet the crust, heat is conducted into cooler wall rocks. If temperatures are sufficiently hot, ______melting occurs as thermal energy moves from hotter to cooler rock.

heat - transfer

what metamorphic rock forms from thermal metamorphism

hornfels

what transporting media can move sediment?

ice, wind, water

During a transgression of the sea, does the location at which beach sand accumulates move inland, move seaward, or remain stationary? Choose one:A. The location does not change.B. seawardC. inland

inland

An immensely thick succession of basalt flows, each of which spread over a vast area, is called a __________. Choose one:A. flood basaltB. dike swarmC. subaerial volcanoD. large igneous province

large igneous province

Photo B depicts a(n)_________accumulation. The eruption responsible for this accumulation began about 36 hours before the photo was taken. Therefore, the maximum age of the black rock visible in the photo is ________hours.

lava flow, pyroclastic

what is the order of sediment from less mature to mature - what does it look like?

less mature: many different sizes of sediment medium: the big grains are settled out and have become more similar in sizing most mature: all grains are the same side

what are key characteristics of limestone and marble?

limestone is the protolith of marble marble is a uniform mass of interlocking calcite crystals as limestone metamorphoses into marble, fossils, poor space, and cement disappear

Geologists use special names for molten rock (melt) and for the settings in which it occurs. Melt that remains underground is termed _______ If it flows onto Earth's surface, it is termed __________Melt that is explosively ejected in a volcanic eruption is called ______________

magma, lava, pyroclastic

Dolostone is composed of the mineral dolomite, which is similar to calcite in limestone, except that dolomite contains________

magnesium

The process by which hydrothermal fluids chemically alter a rock is called __________.

metasomatism

Based on the rock types and the shape of the rock bodies, in what eruption setting did the rock form?

mid-ocean ridge

how can you tell if a rock is igneous

minerals are organized randomly

An igneous rock contains several different minerals. How often do they all crystallize at the same time? a. never b. always c. under certain conditions

never

what are organic sedimentary rocks

oil shale and coal

plastic deformation

permanent change in shape by bending and folding

what is the difference between phase change and metamorphic reactions?

phase change transforms mineral into another mineral with the same composition but different structure. whereas metamorphic reaction is the tranformation/ growth of new minerals that are different from the protolith

what are the steps or neocrystallization

protolith: 1. protolith minerals are consumed by chemical reactions 2. thin clay minerals begin to align 3. clay grains flatten out and become parallel to one another 4. small garnets appear metamorphic rock:

_________ can sometimes be floating in the ocean after an eruption because it has______. Although it has the same composition,__________ does not float because it _________

pumice, has vesicles, obsidian, lacks vesicles

what is the difference between a quartz sandstone and quartzite?

quartzite sandstone are angular grains like a jig saw puzzle, no space between minerals quartz grains have space between grains and rounded and cemented together

What is the difference between replacement chert and biochemical chert? Choose one:A. Replacement chert forms as silica replaces other minerals in a rock and biochemical chert forms from the accumulation of silica shells from plankton.B. Replacement chert forms when silica is removed from a rock and biochemical chert forms when the soft, organic tissue of organisms is fossilized.C. Replacement chert forms when silica plankton shells are replaced by calcite, and biochemical chert forms from the accumulation of dolomite shells.

replacement chert is when the silica replaces other minerals in a rock and biochemical chert is the accumulation of silica shells from plankton

what are two types of clastic sedimentary rocks?

shale and sandstone

silica ________ relative to magnesium oxide and iron oxide. The term___________is used to describe rocks with an abundance of the former, and _________describes rocks with much less.

silica, felsic, mafic

Which of the following foliated metamorphic rocks has the smallest grain size? Choose one:A. gneissB. migmatiteC. schistD. metaconglomerateE. slateF. phyllite

slate

true or false? biochemical rock can form from the shells of dead marine organisms

true

what is pressure solution?

wet rock is squeezed and mineral grain edges dissolve, allowing ions to migrate and precipitate elsewhere