Geology 1403 Final Review

How old is the Earth?

4.6 Billion years

What did we get the age of Earth from?

Meteorites

What was the big bang hypothesis for?

Formation of the galaxies

What was the Nebula hypothesis for?

formations of a solar system

What are three basic divisions of earth's interior?

Crust, mantle, core

Thin, rocky, outer skin of earth

Crust

composed of rock peridotite

mantle

iron nickel alloy, generates earths magnetic field

core

the rigid outer part of the earth, consisting of the crust and upper mantle.

lithosphere

the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.

asthenosphere

the region of the earth's atmosphere above the stratosphere and below the thermosphere, between about 30 and 50 miles (50 and 80 km) in altitude.

mesosphere

a liquid layer about 2,300 km (1,400 mi) thick composed of iron and nickel that lies above Earth's solid inner core and below its mantle.

Outer core

Earth's innermost part and according to seismological studies, it is a primarily solid ball with a radius of about 1220 kilometers, or 760 miles

Inner core

author of the continental drift hypothesis

Alfred Wegener

supercontinent formed in the paleozoic era

Pangea

Concept of seafloor spreading is by who?

Harry Hess

plates are separated along the crests of mid oceanic ridges

Seafloor spreading

Magnetic stripes are indicators of what?

magnetic reversals

red and white stripes parallel to oceanic ridges illustrate what?

magnetic reversals

lithosphere is broken into what?

plates

Plates move apart, constructive margins, zone of seafloor spreading, plates grow along these boundaries

Divergent plate boundaries

plates move toward each other, destructive margins, subduction zones in deep ocean trenches, plate is destroyed along the boundary

Convergent plate boundaries

what is an oceanic-oceanic convergent plate boundary? definition and example

two ocean plates converge. Aleutian island arc, North pacific ocean

what is an oceanic-continental convergent plate boundary? definition and example

an oceanic plate and a continental plate converge. Andes mountains

what is an continental-continental convergent plate boundary? definition and example

two continental plates converge. Himalaya mountains, tibet

what type of boundary has conservative margins and transform?

Transform fault boundaries

each plate is bounded by a combination of the

three types of boundaries

What is the basic driving force of plate tectonics

convective flow in the mantle

the convective flows export heat from deep in the mantle to the top of the

asthenosphere

two other mechanisms that drive plate motion

slab pull and slab suction

________ are building blocks of minerals

elements

________ are the building blocks of rocks

minerals

solid aggregate of minerals

rock

most common elements? 2

silicon and oxygen

most common minerals?

silicates

most common silicates?

quartz, clay minerals, and mica group (mineral muscovite)

most common non silicates?

Carbonates

what are carbonates composed of?

CaCO3- calcite

calcite is dissolved by what?

rain and ground water

what are two physical properties of minerals?

Cleavage and fracture

The tendency of a mineral to break along flat planar surfaces as determined by the structure of its crystal lattice.

Cleavage

The way a mineral breaks other than along a cleavage plane.

Fracture

What are the two types of igneous rocks?

Intrusive and extrusive

whats another name for an intrusive igneous rock?

plutonic

whats another name for an extrusive igneous rock?

volcanic

The size, shape, and arrangement of mineral grains

texture

what does texture tell us about the rock?

the origin

intrusive rocks have a _____ rate of cooling and form ________ crystals

slow, large

extrusive rocks have a _____ rate of cooling and form ________ crystals

fast, many small

very fast rates of cooling of rocks forms what?

glass

igneous rocks are composed primary of what?

silicate minerals

Dark silicates include which minerals?

Olivine, pyroxene, amphibole, and biotite

whats another name for dark silicates?

ferromagnesian

Light silicates include which minerals?

Quartz, muscovite, and feldspars

whats another name for light silicates?

nonferromagnesian

igneous composition of continental crust?

granitic

igneous composition of continental crust, stratovolcanoes?

andesitic

igneous composition of oceanic crust?

basaltic

composition of the mantle?

peridotite (ultramafic)

Largest type of volcano

shield volcano

example of a shield volcano

Hawaii

Medium sized volcano

composite cone (Stratovolcano)

Smallest volcano

Cinder cone

deadly pyroclastic flow

lahar

global distribution of igneous activity is not random, it is associated with these three things:

subduction zones, mid ocean ridges, and intraplate volcanism

what are subduction zones associated with?

convergent plate boundaries

what are mid ocean ridges associated with?

divergent plate boundaries

______ is related to mantle plums (below surface) and rift zones (at surface)

intraplate volcanism

Where is intraplate volcanism located?

lithospheric plate

What are the two types of weathering?

Mechanical and chemical

Breaking of rocks into smaller pieces

Mechanical weathering

breaks down rock components and internal structures of mineral

chemical weathering

______ and ______ are the end products of chemical weathering

clay and quartz

The rate of weathering depends on these three things:

surface area, rock characteristics, and climate

_______ and _______ climate most effectively disintegrates and decomposes rocks.

warm, moist

rounded corners, spots around minerals, and traces of dissolution show what about a rock or mineral?

evidence of weathering

what are the four steps that form a sedimentary rock?

transport, deposition, burial, and lithification

what are the two types of sedimentary rocks?

detrital and chemical

this type of sedimentary rock is formed from particles, which have been transported, deposited, and buried and undergone the lithification process

detrital

main two minerals in detrital rocks

clay and quarts

other common minerals in detrital rocks that are not the main rocks are

micas and feldspars

these sedimentary rocks precipitated from solution or through activities of water dwelling organisms

chemical

what are the three major textures of sedimentary rocks?

clastic, bioclastic, and nonclastic

texture made of inorganic particles, all detrital rocks have this texture

clastic

texture made of rocks containing parts of animal skeletons, shells, tests

bioclastic

crystalline structure (rock salt and rock gypsum have this texture)

nonclastic

three agents of metamorphism

heat, pressure, and active fluids

parent rock determines the ____________ of a metamorphic rock

chemical composition

two metamorphic textures?

foliated and non foliated

This texture is caused by the parallel orientation of microscopic grains. The name for the rock with this texture is slate , and the rock is characterized by a tendency to separate along parallel planes. Type of foliated texture

Slaty cleavage

This texture is formed by the parallel arrangement of platy minerals, usually micas, that are barely macroscopic (visible to the naked eye). The parallelism is often silky, or crenulated. The predominance of micaceous minerals imparts a sheen to the hand specimens. rocks associated with this are phyllite. type of foliated texture.

phyllitic

mode of foliation that occurs in certain metamorphic rocks . It reflects a considerable intensity of metamorphism—i.e., changes resulting from high temperatures, pressures, and deformation. rocks with this foliated texture are called schist.

schistosity

This is a coarsely foliated texture in which the minerals have been segregated into discontinuous hands, each of which is dominated by one or two minerals. These bands range in thickness from 1 mm to several centimeters. The individual mineral grains are macroscopic and impart a striped appearance to a hand specimen. Light-colored bands commonly contain quartz and feldspar. and the dark hands are commonly composed of hornblende and hiotite. Accessory minerals are common and are useful in applying specific names to these rocks. A rock with this foliated texture is called a gneiss.

gneissic

Metamorphic rocks with no visible preferred orientation of mineral grains have this texture

nonfoliated

relative dating has how many laws/principles?

5

the principle that in a series of stratified sedimentary rocks the lowest stratum is the oldest, and the younger rocks are on the top

Principle of superposition

the principle that fossils succeed each other in a definite order; any rock layer can be identified and dated on the basis of the fossil content

principle of faunal/fossil succession

the principle where sedimentary layers are initially deposited in horizontal layersThe forces of reality beat up on the earth and break it into small pieces, which then wash down rivers to the ocean and settle out on the seafloor in horizontal layers

principle of original horizontality

the principle in which the thing being cut is older than the thing doing the cutting

principle of cross cutting relationships

the principle where a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous.

Unconformities