Geology Final Review

Past exams that he is making the final from

The materials composing Earth and the processes that operate on and beneath its surface

What does physical geology primarily examine?

4.6 billion years

How old is planet Earth?

Uniformitarianism

What principle is summarized by the phrase “The present is the key to the past”?

Nebular Theory

Which theory explains the origin of our solar system as evolved from a large, rotating cloud of gas and dust?

crust, mantle, core

Based on its chemical composition, the Earth can be divided into these three layers.

fossils matching across seas, matching geological features, similarities between coastlines now separated by large oceans

What evidence do geologists have about the supercontinent Pangea?

plates move apart and new seafloor is created

Divergent plate boundaries are where ___

plates move towards each other, can create mountain belts or recycle oceanic lithophere

Convergent plate boundaries are where ___

plates grind past each other without the production or destruction of lithosphere

Transform plate boundaries are where ___

thickness and sediment increasing away from the ridge crest, hotspots and formation of volcanic island chains, magnetic reversals as recorded as new ocean floor is created

What evidence do Earth Scientists have to support seafloor spreading?

igneous, sedimentary, metamorphic

three types of rocks

naturally occurring, solid crystalline structure, definite chemical composition

characteristics used to define a mineral

precipitation, crystallization, deposition

three general processes that form minerals

silicates

which mineral group is most common on Earth?

weathering

a process by which rocks are broken down into pieces, then transported and deposited as sediment

crystallization

a process by which magma or lava solidifies, forming igneous rocks

metamorphism

a process by which rock is changed, mainly due to being buried deep in the crust and is exposed to high heat and pressure

divergent plate boundary

Which type of plate boundary is characterized by the creation of new seafloor as plates move apart?

Deep ocean trench

What is the main feature formed at a convergent plate boundary where an oceanic plate is subducted beneath a continental plate?

Transform plate boundary

Which type of plate boundary is characterized by neither destruction nor creation of crust?

lava

What is magma called when it reaches the Earth’s surface?

melt, crystals, volatiles

What components are typically found in magma?

intrusive

What type of igneous rock is formed when magma crystallizes at depth?

fine-grained

What texture is characteristic of extrusive igneous rocks?

silicon and oxygen

Which elements make up the vast majority of rock forming minerals in igneous rocks?

rate of cooling

Which factor primarily influences the texture of igneous rocks?

porphyritic

What texture is characterized by large crystals embedded in a matrix of smaller crystals?

glassy

Which igneous rock texture results from extremely rapid cooling and lacks an orderly crystalline structure?

more silica than mafic rocks

Felsic igneous rocks contain___

decompression melting, increase in temperature, addition of water causing partial melting

processes involved in the generation of magma

weathering, transportation, lithification

Which processes are involved in the formation of sedimentary rock?

90%

What percentage of Earth’s land surface is covered by sedimentary rocks?

the mechanical or chemical decomposition of any rock type

What is weathering?

the settling of sedimentary particles

Deposition of sediment is___

shale

What is the most abundant sedimentary rock?

organic

Which type of sedimentary rock is formed from carbon-rich remains of organisms?

particle size

What is the primary characteristic used to distinguish among clastic sedimentary rocks?

compaction and cementation of sediment

What best describes the process of lithification?

limestone

What kind of rock is primarily composed of the mineral calcite and can form both from inorganic and biochemical origins?

from the soluble material produced largely by chemical weathering through precipitation from a solution

Chemical sedimentary rocks can form ___

conglomerate has rounded clasts, breccia has angular clasts

the main difference between conglomerate and breccia is ___

the degree of similarity in particle size

What is sorting?

through the restriction of a seaway, with water becoming oversaturated

How does the evaporite halite (rock salt) form?

Anthracite

What type of coal has undergone a degree of metamorphism?

strata or beds

what type of sedimentary structure indicates settling of particles through time with distinguishable breaks in deposition?

gradual change from coarser to finer particles

graded beds can be identified by the ___

ripple marks

small waves lithified in the sedimentary rock

mud cracks

This type of sedimentary structure form from alternating wet and dry conditions

aid in interpretation of geological past, important time indicators, paleoclimate indicators

Why are fossils important for paleontologists?

heat

what is the primary agent responsible for driving metamorphism?

confining pressure is equal in all directions, differential stress is greater in one direction

What is the main difference between confining pressure and differential stress?

in deep ocean trenches and along fault lines

What are the two primary geological conditions where metamorphism mostly occurs?

contact metamorphism

Which type of metamorphism results from the rise in temperature when magma invades a host rock?

slate

which foliated rock forms from a parent rock of shale?

foliated metamorphic rock

what type of metamorphic rock shows a preferred origination of materials?

nonconformity

a type of unconformity in which younger strata overlie older metamorphic or intrusive igneous rocks

70000 years

carbon 14 dating can be used to date events as far back as approximately ___

Mesozoic

which era is between the Paleozoic Era and Cenozoic Era?

The Principle of Superposition

states that in an undeformed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below

The Principle of Cross Cutting Relationships

states that a geologic feature that cuts across rocks must form after the rock features it cuts through

3.5 billion

the oldest rocks so far found on the Earth may be about how many years old?

half life

in radiometric dating, the length of time for ½ of the radioactive isotope to decay

Cenozoic

in what geological time era are we currently in?

Precambrian

is a term used to define 88% of Earth’s history prior to the start of the Paleozoic

hydrolysis, oxidation, dissolution

three types of chemical weathering processes

exfoliation dome

as over burden is removed and confining pressure is reduced, the outer parts of a granitic mass expand and separate into slabs or sheets of rock, eventually separating and peeling off creating ___

eluviation and leaching

in the idealized soil horizon the E horizon is a zone of ___

spheroidal weathering

many rock outcrops have a rounded appearance because chemical weathering works inward from exposed surfaces

Precambrian

the most recent geological time, began about 66 million years ago

limestone

granite and limestone are exposed at the Earth’s surface in a hot, humid region, which rock will weather more rapidly?

disconformity

a type of unconformity in which the sedimentary beds above and below the unconformity are parallel

aluminum and iron oxides

climate is a major factor in soil formation, the soil in typical forests under a tropical climate is extremely leached and mature. These soils likely contain large amounts of ___

frost wedging

what process is a type of mechanical weathering?

regolith

a layer of rock and mineral fragments produced by weathering that covers the Earth’s surface

loam

soils in which no particle size predominates (equal mix of clay, silt, and sand)

plants, animals, and microbes, topography, climate, time, parent material

five main factors that control the formation of soils

Amazon

will the same granite rock weather faster in Antarctica or the Amazon rain forest?

composite

what type of volcano is Mt. St. Helens?

caldera

a volcanic landform that is a large steep-sided depression having a somewhat circular form and greater than 1km in diameter

lahar

a debris flow on the slope of a volcano that results when unstable layers of ash and debris become saturated and flow downslope

Mauna Loa

largest shield volcano on Earth

underwater

pillow lavas form ___

flood basalt

fissure eruptions usually emit low viscosity, fluid lava that blankets wide areas