Gel 50 Midterm 1

Front 1

asthenosphere

Back 1

the portion of mantle immediately below lithosphere, about 300 km thick , acts like moldable solid

Front 2

Mantle plume

Back 2

narrow jet of hot, solid material rising from deep within the mantle

Front 3

climate

Back 3

produced by weather cycles, can be described by averaging temperature and other variables over many years of observation

Front 4

climate system

Back 4

includes all the earth systems components that determine climate on a global scale and how climate changes with time. includes interactions between atmosphere and hydro-, bio-, and cryo-spheres

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convection

Back 5

process in which hotter material rises and cooler material sinks

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core

Back 6

compromised mostly of iron-nickel alloy, has solid and liquid layers, incredibly dense

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crust

Back 7

made of low density silicates, which are rich in aluminum and potassium

Front 8

earth system

Back 8

all parts of our planet and all their interactions, taken together. magor components are climate, plate tectonic, and geodynamo systems. its an open system that exchanges energy and mass with its suroundings

Front 9

fossil

Back 9

traces of organisms preserved in the geologic record

Front 10

geodynamo

Back 10

involves interactions that produce a magnetic field deep inside earth, in its liquid outer core. more like an electromagnet than a permanent magnet

Front 11

geologic record

Back 11

information preserved in the rocks that have been formed at various times throughout earth's history

Front 12

geology

Back 12

branch of earth science that studies all aspects of the planet: history, composition, internal structure, surface features

Front 13

Geosystem

Back 13

specialized subsystems that produce specific types of activity, such as climate change or mountain building

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inner core

Back 14

solid metal sphere. radius is about 1220 km. about 2/3 size of the moon

Front 15

lithosphere

Back 15

includes crust and top part of mantle down to about average depth of 100 km, acts like brittle shell

Front 16

magnetic field

Back 16

produced in liquid outer core, reaches far out into space, protects planet from solar winds and radiation, causes rocks to become slightly magnetized when formed

Front 17

mantle

Back 17

shell of silicate-rich rock that surounds the core. contains more magnesium and iron than crust

Front 18

outer core

Back 18

liquid core surounding solid inner core

Front 19

plate tectonic system

Back 19

made up of the convecting mantle and its overlying lithosphere plates

Front 20

principle of unifortarianism

Back 20

for the most part, the processes we see in action on earth today have worked in much the same way throughout the geologic past. "the present is the key to the past"

Front 21

scientific method

Back 21

general procedure for discovering how the universe works through systematic observations and experiments

Front 22

seismic wave

Back 22

an earthquake occurs when geologic forces cause brittle rocks to fracture, sending out vibrations like the cracking of ice along a river

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topography

Back 23

features of earth's surface. mountains, valleys, and other ups and downs

Front 24

hypothesis

Back 24

tentative explanation based on data collected through observations and experiments. is presented to other scientists, has to be confirmed by others to be credible

Front 25

theory

Back 25

coherent set of hypotheses that explain some aspect of nature

Front 26

physical laws

Back 26

general principles about how the universe works that can be applied in almost every situation

Front 27

scientific model

Back 27

a precise representation of how a natural system behaves. scientists combine related ideas in a model to test the consistency of their knowledge

Front 28

compression waves

Back 28

type of seismic wave. expand and compress the material they move through as they travel though solid, liquid, and gas

Front 29

shear waves

Back 29

type of seismic wave. move material from side to side, only in solids, which resist shearing, liquids and gas have no resistance to this type of motion

Front 30

core-mantle boundary

Back 30

at about 2890 km depth

Front 31

Mohorovicic discontinuity (Moho)

Back 31

separates the crust and the mantle. at about 7 km under oceans and 40 km under continents

Front 32

continental boyancy

Back 32

continents are thicker but less dense, so they "float" on top of mantle and rise higher than oceanic crust

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transition zone

Back 33

separates upper and lower mantle, where rock increases in density in series of steps

Front 34

the 4 elements that make up 90% of earths mass

Back 34

iron, oxygen, silicon, and magnesium

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heat engine

Back 35

transfers heat into mechanical motion or work

Front 36

internal heat engine of earth

Back 36

powered by the heat energy trapped in its deep interior during its violent origin aad released inside the planet by radio activity. drives movement in manlte and core, supplies energy the melts rock, moves continents, lifts mountains

Front 37

external heat engine

Back 37

driven by solar energy. energizes ocean and atmosphere, climate and weather

Front 38

weather

Back 38

term used to describe temperature, precipitation, cloud cover, and winds observed at a particular location and time on earth's suface

Front 39

theory of plate tectonics

Back 39

lithosphere not continuous shell, it's broken into about a dozen large plates that move over the earth's surface at rates of a few centimeters a year. each plate is a rigid unit that rides on top of the asthenosphere. they're thicker in older, colder parts, forces that push and pull them come from mantle. hot mantle material rises at places where plates separate to form new lithosphere. lithosphere becomes more rigid as it moves away, eventually sinking back into mantle

Front 40

continental drift

Back 40

large scale movement of continents

Front 41

convergent boundary

Back 41

plates come together and one plate is recycled into the mantle . plate area decreases. trench, mountains on overriding plate parallel to trench, slight bump on subducting plate running next to trench

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divergent boundary

Back 42

plates move apart and new lithosphere is formed. plate area increases. creates rift valleys, ridges

Front 43

geodesy

Back 43

the ancient science of measuring the shape of the earth and locating points on its surface

Front 44

island arc

Back 44

chain of volcanoes that forms behind the trench at convergent boundaries

Front 45

isochron

Back 45

boudaries between the bands of rocks/ seafloor ages that connect rocks of equal age. a contour that conects rocks of equal age

Front 46

magnetic anomaly

Back 46

narrow, parallel bands of alternating magnetic strength caused by the magnetic poles of earth reversing while rocks were forming

Front 47

magnetic time scale

Back 47

created by measuring the ages of rocks throughout the magnetic anomalies to create a time scale of when reversals happened

Front 48

mid-ocean ridge

Back 48

occurs at divergent boudaries. an under water mountain range that exhibits earthquakes, volcanism, and rifting, all caused by the tensional (stretching) forces of the mantle convection that are pulling the two plates apart

Front 49

Pangaea

Back 49

super continent, proposed in 1915 by Alfred Wegner, german meteorologist

Front 50

plate tectonics

Back 50

seafloor spreading, creating new lithosphere, lithosphere being recycled at subduction zones

Front 51

relative plate velocity

Back 51

the velocity at which one plate moves related to another

Front 52

Rodinia

Back 52

super continent before pangaea

Front 53

seafloor spreading

Back 53

process by which the convection currents in the mantle could push and pull continents apart, creating new oceanic lithosphere

Front 54

spreading center

Back 54

where two plates are moving apart. seafloor spreads as hot molten rock, called magma, wells up into the rifts to form new oceanic crust

Front 55

subduction

Back 55

process in which one plate descends beneath another

Front 56

transform fault

Back 56

plates slide past eachother. plates are neither created nor destroyed

Front 57

oblique boundaries

Back 57

combine converging or diverging boundaries with some amount of transform faulting

Front 58

thermoremanent magnetization

Back 58

iron-rich lava cools, becomes slightly but permanetly magnetized in direction of earth's magnetic field

Front 59

magnetic chrons

Back 59

major periods during which the magnetic field is normal or reversed, lasting about 1/2 million years

Front 60

positive magnetic anomoly

Back 60

rocks magnetized in normal direction record as a locally stronger field

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negative magnetic anomoly

Back 61

rocks magnetized in reverse direction records as a locally weaker field

Front 62

asteroid

Back 62

left over planetesimals. one of more than 10,000 small celestial bodies orbiting the sun, most of them between the orbits of mars and jupiter

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dwarf planet

Back 63

lie with in the belt of icy bodies that is the source region for comets. tiny size, unusual orbit, rock-gas-ice composition

Front 64

exoplanet

Back 64

planets that lie outside the solar system

Front 65

flake tectonics

Back 65

occurs on venus. as the vigorous convection currents push and stretch the surface, the crust breaks up into flakes or crumples like a rug, and blobs of hot magma bubble up to form large land masses and volcanic deposits

Front 66

gravitational differentiation

Back 66

the transformation of random chunks of primordial matter into a body whose interior is divided i to concentric layers that differ from one another both physically and chemically

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heavy bombardment

Back 67

period during which the planets collide frequently with the residual materials that still clutter the solar system

Front 68

meteorites

Back 68

chunks of material from outer space that strike earth, most are tiny pieces of asteroids ejected from belt during collisions

Front 69

nebular hypothesis

Back 69

origin of galaxy is rotating orb of gas and dust. gravity causes it to contract, speeds it up, flattens it into disk. suns forms, then planetesimals, then planets

Front 70

planetesimal

Back 70

km sized chunks form when gravity caused dust and condensing material to clump together

Front 71

solar nebula

Back 71

disk of gas and dust that surounds proto-sun after it forms

Front 72

terrestrial planet

Back 72

mercury, venus, earth, mars. planets closest to sun, made up of the denser and heavier materials (silicates/iron/nickel)

Front 73

giant outer planets

Back 73

jupiter, saturn, uranus, neptune. made up of the lighter and more volatile elements and gases. have rocky cores

Front 74

asteroid belt

Back 74

some planetesimals collected between mars and jupiter to form belt

Front 75

magma ocean

Back 75

after earth got hit by mars sized object, earth reformed to have an outer molten layer hundreds of km thick

Front 76

mercury

Back 76

thin atmosphere, mostly helium, extremely low atmospheric pressure, no water or wind, 470 C days, -170 C nights. closest density to earth's. core makes up 70% of mass

Front 77

Venus

Back 77

basically hell. incredibly hot, poinsonus, heavy atmosphere, clouds of acid, 85% covered in lava flows, closest to earth in mass and size, signs of tectonic activity

Front 78

mars

Back 78

went through lot of same geologic processes as earth. 1/10 earth's mass. core is 1/2 its radius, thin atmosphere, made entirely of CO2. only water permafrost or ice. shows signs of once being abundant with water

Front 79

moon

Back 79

mostly light materials. small core, 20% of mass. no atmosphere, some evidence there may be ice. craters show no tectonic activity.light-colored areas lunar highlands. dark-colored areas lunar maria. highlands are older

Front 80

pluto

Back 80

dwarf planet

Front 81

anion

Back 81

negative ion

Front 82

atomic mass

Back 82

sum of the masses of an atom's protons and neutrons

Front 83

atomic number

Back 83

number of protons in an atom's nucleus

Front 84

bedding

Back 84

the formation of parallel layers of sediment as particles are deposited

Front 85

biological sediment

Back 85

a sediment formed near its place of deposition as a result of direct or indirect mineral precipitation by organisms

Front 86

carbonate

Back 86

carbonate ion CO3 (2-)

ex: calcite CaCO3

Front 87

cation

Back 87

positive ion

Front 88

chemical sediment

Back 88

a sediment formed at or near its place of deposition from dissolved materials that precipitate from water

Front 89

cleavage

Back 89

tendency of a crystal to split along planar surfaces

Front 90

color

Back 90

the color of a mineral is imparted by the light either transmitted through or reflected by crystals or irregular masses of the mineral

Front 91

contact metamorphism

Back 91

where high temperatures are restricted to smaller areas, as in rocks near or in contact with a magmatic intrusion

Front 92

covalent bond

Back 92

elements that don't like gaining or losing electrons and instead form compounds by sharing electrons. typically stronger than ionic bonds

Front 93

crystal

Back 93

orderly 3-d arrays of atoms in which the basic arangement is repeated in all directions.

Front 94

crystal habit

Back 94

the shape in which individual crystals or aggregates of crystals grow. shapes indicate planes of mineral structure and typical speed and direction of crystal growth

Front 95

crystallization

Back 95

process by which minerals form, in which the atoms of a gas or liquid come together in the proper chemical proportions and in the proper arangement to form a solid substance.

Front 96

density

Back 96

mass/volume

Front 97

disseminated deposit

Back 97

deposits of ore minerals that are scattered through volumes of rock much larger than veins

Front 98

electron sharing

Back 98

the mechanism by which a covalent bond is formed between the elements in a chemical reaction. atoms share electrons

Front 99

erosion

Back 99

the set of processes that loosen soil and rock and move them downhill or downstream to the spot where they are deposited as layers of sediment

Front 100

fracture

Back 100

tendency of a crystal to break along irregular surfaces other than cleavage planes

Front 101

grain

Back 101

a crystalline particle of a mineral

Front 102

hardness

Back 102

a measure of the ease with which the surface of a mineral can be scratched

Front 103

hydrothermal solution

Back 103

hot water solutions. water comes into contact with magma, carries away minerals and ions, which interact to form minerals

Front 104

igneous rock

Back 104

all rocks formed by the solidification of molten rock

Front 105

ion

Back 105

atom or group of atoms that has an electrical charge, either positive or negative, because of the loss or gain of electrons

Front 106

ionic bond

Back 106

formed by electrostatic atraction between ions of opposite charge

Front 107

isotope

Back 107

atoms of the same element with a different number of neutrons

Front 108

lithification

Back 108

process that converts sediments into solid rocks. 2 ways:cementation - minerals precipitate around deposited particles and bind them togethercompaction - particles squeezed together by weight of overlying sediments into a mass denser than the original

Front 109

luster

Back 109

the way the surface of a mineral reflects light

Front 110

magma

Back 110

a mass of hot, molten liquid rock

Front 111

metallic bond

Back 111

metals tend to lose electrons, so they pack together as cations and free moving electrons are shared and dispersed among those cations

Front 112

metamorphic rock

Back 112

all rocks formed by the transformation of preexisting solid rock under the influence of high temperature and pressure

Front 113

mineral

Back 113

defined as naturally occuring, solid crystalline substance, usually inorganic, with a specific chemical composition

Front 114

mineralogy

Back 114

branch of geology that studies the composition, structure, appearance, stability, occurence, and the associations of minerals.also termed used to describe relative proportions of a rock's component minerals

Front 115

mohs scale of hardness

Back 115

1 talc

2 gypsum

3 calcite

4 flourite

5 apatite

6 orthoclase

7 quartz

8 topaz

9 corundum

10 diamond

Front 116

ore

Back 116

a mineral deposit from which valuable metals can be recovered profitably

Front 117

oxides

Back 117

oxygen ion. O (2-)

ex: hematite Fe2O3

lots of ores containing metals

Front 118

polymorph

Back 118

minerals with the same chemical formula but different crystal structures

Front 119

precipitate

Back 119

solute starts to drop out / crystillize out of solution

Front 120

regional metamorphism

Back 120

occurs where high pressures and temperatures extend over a large region, as happens where plates collide

Front 121

rock

Back 121

a naturally occuring solid aggregate of minerals, or in some cases, non-mineral solid matter

Front 122

rock cycle

Back 122

explains how each type of rock is transformed into one of the other two types of rocks. result of interactions between plate tectonic and climate systems. the set of geologic processes that converts rocks of each of the three types into the other two types

Front 123

sediment

Back 123

material deposited on earth's surface by physical agents (wind, water, and ice), chemical agents (precipitation from oceans, lakes, and rivers), or biological agents (living and dead organisms)

Front 124

sedimentary rock

Back 124

all rocks formed from the burial products of layers of sediments, whether they were laid down on land or undersea

Front 125

silicate

Back 125

silicate ion. SiO4 (-4).

most abundant class

ex: olivine (Mg,Fe)2SiO4

Front 126

siliclastic sediment

Back 126

made up of physically deposited particles laid down by running water, wind, ice

Front 127

specific gravity

Back 127

a standard measure of density. weight of mineral / weight of equal volume of water at 4 degrees C

Front 128

streak

Back 128

color of the fine deposit of mineral powder left behind on an abrasive surface when a mineral is scraped across it

Front 129

sulfate

Back 129

sulfate ion SO4 (2-)

ex: anhydrite CaSO4s

Front 130

sulfide

Back 130

sulfide ion. S (2-)

ex: pyrite FeS2

chief source for ores for valuable metals like coper, nickel, and zinc

Front 131

texture

Back 131

describes sizes and shapes of a rocks mineral crystals or grains and the way they are put together

Front 132

trace element

Back 132

elements that make up less than .1% of a mineral. many varieties of minerals get their color from trace minerals

Front 133

vein

Back 133

hydrothermal solution moving through rocks deposits ore minerals. water cools quickly, minerals precipitate, makes tabular deposits of precipitated minerals called veins

Front 134

weathering

Back 134

all the chemical and physical processes that break up and decay rocks into fragments and dissolved substances of various sizes

Front 135

chemical reactions

Back 135

interactions of the atoms of two or more chemical compounds

Front 136

cation substitution

Back 136

cations of similar size and charges tend to substitute for one another to form compounds having the same crystal structure but differing in chemical composition

Front 137

crystal faces

Back 137

the boundaries of crystals are natural flat surfaces

Front 138

native element

Back 138

occur naturally as unionized pure elements

ex: copper

Front 139

hydroxides

Back 139

OH-

Front 140

halides

Back 140

Cl-, F -, Br-, I-

Halite NaCl

Front 141

silicate structures

Back 141

isolated, single chain, double chain, sheet, 3-d framework

Front 142

aggregate

Back 142

in an aggregate, minerals are joined in such a way that they retain their individual identity

Front 143

intrusive igneous rocks

Back 143

crystallize when magma intrudes into unmelted rock masses deep in the earth's crust

Front 144

extrusive igneous rocks

Back 144

form from magmas that erupt at earth's surface as lava and cool rapidly

Front 145

folliation

Back 145

wavy or flat planes produced when the rock was folded