e & s exam 2

where do coal beds form?

freshwater swamps

Sedimentary rocks constitute approximately ________ of the rocks exposed at the Earth's land surface.

75%

The temperature at which a mineral melts:

is the same temperature at which it crystallizes

Common cementing agents include all of the following EXCEPT:

olivine

The primary cause of mechanical exfoliation is:

the removal by erosion of overlying rock and soil

The term "metamorphic grade" refers to:

the severity of metamorphic conditions on the parent rock

Detrital sediment texture is identified on the basis of:

the size, shape, and arrangement of the particles

Gypsum & rock salt are chemical sedimentary rocks. How do they form?

the water evaporates

mass wasting

transfer of rock material downslope under the influence of gravity

Continental crust is composed mostly of rocks formed by:

Regional metamorphism

igneous intrusions

Rhyolite - Plutonic (formed below surface) - Closely related to granite Granite - Plutonic (formed below surface) - Closely related to rhyolite Diorite - Plutonic (formed below surface) - Closely related to andesite Andesite - Volcanic (formed at surface) - Closely related to diorite Gabbro - Volcanic ( formed at surface) - Closely related to basalt Basalt - Volcanic (formed at surface) - Closely related to gabbro

Which of the following types of rocks can become metamorphic rocks?

Sedimentary, igneous, or metamorphic rocks

In an igneous rock with two distinct classes of crystal size, which of the following is true?

The rock cooled slowly at first, but then the cooling process speeded up

Plutonic rocks are characterized by which type of texture?

Phaneritic

What is the last mineral to form according to Bowen's reaction series?

Quartz

In metamorphic rocks, foliation is caused by:

directed pressure

metamorphic rocks: NONFOLIATED

- Contain equidimensional crystals - Resembles a coarse-grained igneous rock - marble & quartzite

Bowen's reaction series

- Found diff minerals crystallize at diff temps - gives you 3 things: temperature, type of source area, & the back igneous rock types

true soil

- O, A, E, & B horizons - Called the "solum"

horizons

- O: organic matter (top soil) - A: organic & mineral matter (top soil) - E: little organic matter - B: zone of accumulation - C: partially altered parent material

loam

- a mixture of all 3 sizes: sand (large size), silt, & clay (small size) - best suited for plant life

joints

- crack in the rock where there is no movement; they increase the surface area; - they affect how fast you're going to get weathering; where more joints are, weathering will occur faster - types: preexisting, expansion, & unloading

physical changes of metamorphic rocks include:

- deformation of objects - rotation - shearing - small-scale folding - fracturing

intrusive rocks

- plutonic - formed below the surface

chemical changes of metamorphic rocks include:

- pressure solution - recrystallization - remobilization

extrusive rocks

- volcanic - formed at the surface

lithification process: COMPACTION

1) clay particles rest at various orientations, resulting in open space; once compacted, clay particles line up & open space decreases significantly. Or 2) sand grains rest on one another but don't fit together tightly; if compacted, grains nestle together & space decreases

In which of the following locations would a rich soil accumulate most quickly?

A relatively flat topography in a moist, mid-latitude climate

Which of the following statements concerning the formation of coal is NOT true?

Coal is composed primarily of the remains of microorganisms

soil

Combination of mineral matter (the regolith), water, air, & organic material that supports the growth of plants

Which of the following statements concerning cooling magma is NOT true?

Composition of the magma remains the same as it crystallizes

What is the process by which a single parent magma can produce a variety of rocks of different composition?

Fractional crystallization

What generally accelerates the pace of chemical reactions?

Heat

Under which of the following conditions would rocks melt at a lower temperature?

High water content, low pressure

Which of the following statements about the creation of magma is true?

Increasing pressure raises the melting point except in the presence of water

Which of the following is NOT true about Bowen's reaction series?

It shows that minerals never form in the same order

transported soil

Parent material has been carries from elsewhere & deposited

residual soil

Parent material is the bedrock

Which of the following statements about the rounding of boulders by chemical weathering is NOT true?

Rounding occurs because the portions of a rock on the edges and corners are less stable than portions in the interior of the rock.

Which of the following statements about the B horizon is NOT true?

The B horizon generally lies above the E horizons

Which of the following statements about soil horizons is NOT true?

The color of the E horizon results from humus that has leached downward from the A horizon

Which of the following statements concerning batholiths is NOT true?

They commonly consist of the mafic intrusive rock gabbro

What is the primary difference between weathering and erosion?

Weathering is the breaking down of rocks; erosion is the transporting of rock fragments

Which of the following transport media generally results in the most well-sorted sediments?

Wind

A sill is a:

a concordant tabular pluton

The term "foliation" in metamorphic rocks refers to:

a consistent orientation of the mineral grains perpendicular to the direction of greatest pressure

A dike is a:

a discordant tabular pluton

Water facilitates metamorphic reactions by:

aiding movement of atoms and ions

Rocks and minerals are most stable when they:

are in the environment in which they formed

differential weathering

caused by variations in composition; creates unusual & spectacular rock formations & landforms

The rocks that make up the oceanic crust are all:

basalts and gabbros

the 3 types of plutons are:

batholith, sill, & dike

unloading joints

can cause thin slabs to peel from rock-exfoliation

The dissolution of limestone to form caves results from water combining with:

carbon dioxide to form carbonic acid

Mechanical weathering can:

change the size and shape of rock structures

Carbon dioxide is added to the atmosphere by all of the following processes EXCEPT:

chemical weathering of silicate minerals

Sedimentary rocks: LITHIFICATION PROCESS

compaction & cementation

The classification of intrusive igneous structures depends on all of the following EXCEPT:

composition and texture

The ultimate mineralogy of a metamorphic rock is determined by:

composition of the parent rock

Metamorphism that results entirely from the heat of magma is:

contact metamorphism

All of the following statements about cross-bedding are true EXCEPT:

cross-beds form when particles drop from still water

Sedimentary layers, or beds, indicate all of the following EXCEPT:

disturbance of sediments by organisms

Sedimentary structures such as graded bedding, cross-bedding, and ripple marks are formed:

during or after deposition, but before lithification

expansion joints

form as pressure decreases as rock is brought up from depth

preexisting joints

form from burial, tectonics, cooling, etc.

Water performs all of the following functions in chemical weathering EXCEPT:

freezes in the cracks, facilitating frost wedging

The texture of obsidian and pumice is:

glassy, resulting from rapid cooling

The most important factor contributing to metamorphism is:

heat

As pressure increases, the melting-point of a rock:

increases

As the rate of cooling decreases, particle size in an igneous rock:

increases

Viscosity of a magma:

increases with decreasing temperature and high silica content

All of the following statements concerning contact metamorphism are true EXCEPT:

it only occurs at great depths

Gneiss can be distinguished from other metamorphic rocks by:

its dark and light mineral bands

The most distinctive feature of the E horizon is:

its lack of both organic matter and soluble minerals

The primary difference between lithostatic pressure and directed pressure is:

lithostatic pressure pushes in on rocks equally from all sides, while directed pressure acts in one principal plane.

The rock that results from the metamorphism of relatively pure limestone is:

marble

Metamorphic rocks form through all of the following processes EXCEPT:

melting and recrystallizing

Frost wedging would be most prominent in:

mid-latitude regions where temperatures hover around 0°C (32°F) during certain seasons

The primary difference between magma and lava is that:

one is below the ground, the other is above the ground

lithification process: CEMENTATION

open spaces b/w grains allow mineral-rich water to flow through & deposit minerals, binding grains together & making sediment harder by: a. Calcite b. Silica c. Iron Oxide

The main difference between a breccia and a conglomerate is:

particle shape

Graded beds are commonly formed by:

particles settling at different rates

Vegetation promotes chemical weathering by:

producing organic acids upon decay

Metamorphism of quartz sandstone produces:

quartzite

metamorphic rocks: FOLIATED

slate, schist, & gneiss

The main difference between regolith and soil is:

soil is the upper few meters of regolith, containing both minerals and organic matter.

The geothermal gradient describes how:

temperature increases with depth within the Earth

The two properties used most to classify igneous rocks are:

texture and mineral composition.

In a temperate region, the most distinctive feature of the O horizon of a soil is:

the abundance of both organic matter and living organisms

In geology, the term "oxidation" often refers to:

the chemical combination of a mineral's ions with oxygen

Sedimentary structures allow a geologist to determine:

the depositional environment of detrital sediments

Hydrolysis refers to:

the displacement of a mineral's ions by the H+ or OH- ions from water

Inorganic chemical sedimentary rocks are derived from:

the dissolved products of chemical weathering that precipitate from solution

Oolitic limestone forms as the result of:

the precipitation of calcium carbonate in concentric coats around grains of sand

The term texture refers to:

the size and shape of the mineral components

Sediments are classified as either detrital sediment or chemical sediment on the basis of:

the source of the sediments

Weathering by thermal expansion and contraction involves all of the following factors EXCEPT:

the thermal expansion of air within fractures in rocks enlarges the openings

In general, chemical weathering would occur most rapidly in a:

warm, moist climate

The single most important factor controlling the rate of chemical weathering is:

water

The first criterion used to classify metamorphic rocks is:

whether it is foliated or nonfoliated.