Geology Exam One

Front 1

What is Geology?

Back 1

Geology is the study of Earth.

Front 2

Plate Tectonics

Back 2

Plate Tectonics theory explains that the outer shell layer of the Earth, lithosphere, is broken into slabs called plates. Plates move slowly and change size over time.

Front 3

Plate Boundaries
Divergent

Back 3

Plate boundaries stretch and separate. (move away from each other) As plates separate, the gash is filled with molten material rising from the asthenosphere.

Front 4

Plate Boundaries
Convergent

Back 4

Plates collide head on into each other. One will plunge into the deeper mantle in a process called subduction. The overriding plate experiences volcanic activity. Earthquakes, mountains, volcanoes form from convergent boundaries.

Front 5

Plate Boundaries
Transform

Back 5

Plates slide past each other without creation or destruction of the lithosphere.

Front 6

Properties of Minerals.

Back 6

Luster, Specific Gravity, Density, Crystal Faces, Hardness, Cleavage, Color, Streak

Front 7

Luster is..

Back 7

the property that describes how mineral surfaces reflect light

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Crystal faces are..

Back 8

smooth, flat surfaces with regular geometric outlines. Ex: Calcite and Quartz both six sided but with different crystal faces.

Front 9

Density is..

Back 9

a measure of the mass of a material divided by its volume.

Front 10

Specific gravity is..

Back 10

is the weight of a material in air divided by the weight of an equivalent volume of water at 4 'C. Specific gravity and density often have the same value.

Front 11

Hardness is..

Back 11

is the measure of a mineral's resistance to scratching.

Front 12

Mohs Hardness Scale is..

Back 12

from 1 to 10. Diamond being the 10. Quartz 7. Calcite 3. Fingernail 2.5; Copper Penny 3.5; Wire Nail 4.5; Glass 5.5; porcelain plate 6.5; pocket knife blade 7.

Front 13

Cleavage is..

Back 13

description of the flat, smooth planes along which some minerals break and the shape of the resulting fragments.

Front 14

Color is...

Back 14

not always a reliable property for identifying a mineral because of variations.

Front 15

Streak is..

Back 15

the color of the residue produced by scratching a mineral on a nonglazed porcelain plate. A mineral may vary in color but the streak is always the same.

Front 16

A polymorph is..

Back 16

minerals with identical chemical composition but with different arrangements of atoms. EX. Calcite and Aragonite.

Front 17

A mineral defined..

Back 17

a naturally occurring solid, usually inorganic, with a definite, only slightly variable chemical composition and an ordered atomic structure.

Front 18

Color is determined by a mineral's...

Back 18

chemical composition

Front 19

Most physical properties are determined by...

Back 19

atomic structure. EX. Graphite and Diamond, both made out of carbon but diamond is hard and graphite is a 2.

Front 20

Silicate Minerals are...

Back 20

the primary rock forming minerals in the crust.

Front 21

Silicates:

Back 21

olivine, pyroxene, amphibole, micas, serpentine, feldspar, quartz, garnet

Front 22

Nonsilicates:

Back 22

calcite/aragonite, dolomite, magnetite, hematite, corundum, halite, gypsum, gold, copper, chalcopyrite, pyrite, sphalerite, galena

Front 23

Carbonate minerals:

Back 23

calcite, aragonite and dolomite. Typically precipitate from water.

Front 24

Descriptive classifications

Back 24

group items of similar appearance.

Front 25

Genetic classifications

Back 25

group features or phenomena by noting similarities in the process that cause or create them.

Front 26

Sedimentary rocks are formed by..

Back 26

deposition and precipitation of products formed by the breakdown of older rocks under the ordinary conditions found in Earth's surface environment.

Front 27

Physical weathering

Back 27

causes rocks to disintegrate into smaller rocks or into even smaller mineral grains.

Front 28

Chemical weathering

Back 28

involves reactions between minerals and water to produce dissolved ions and new minerals.

Front 29

Clastic sediment

Back 29

minerals or rock fragments produced by weathering

Front 30

chemical sedimentary rocks

Back 30

mineral constituents dissolved in water by chemical weathering may later precipitate as new mineral crystals if conditions of water temp, pressure, or element composition change appropriately.

Front 31

chemical sedimentary rocks are composed mostly of..

Back 31

carbonates, sulfates, common salts, and some oxides. EX: calcite, dolomite, gypsum halite, and hematite

Front 32

lithification

Back 32

compaction under the weight of accumulating sediment and precipitation of cementing minerals between grains convert loose sediment into consolidated sedimentary rocks.

Front 33

bedding

Back 33

sedimentary rock's distinctive layering

Front 34

Igneous rocks

Back 34

crystallize from molten material called magma which originates from melting rock within the Earth. Composed mostly of silicate minerals.

Front 35

volcanic rocks
extrusive

Back 35

solidify at the surface

Front 36

plutonic rocks
intrusive

Back 36

solidify beneath the surface

Front 37

massive

Back 37

rocks that lack layering

Front 38

metamorphic rocks

Back 38

result from changes of preexisting rocks, occurs at high temperatures, high pressures, conditions found within Earth

Front 39

regional metamorphic rocks

Back 39

rocks originating at or near the surface are forced down to great depth and have high pressure exerted on them

Front 40

contact metamorphic rocks

Back 40

seen at bottom of lava flows, most impressive adjacent to igneous intrusions. Magmatic heat together with naturally elevated temperature at depth and large volumes of hot water cause dramatic metamorphic change.

Front 41

Hydrothermal metamorphic rocks

Back 41

form where hot-fluid reactions with rock are the primary cause of metamorphism. Commonly host important metal-ore deposits.

Front 42

Neptunist View

Back 42

Abraham Werner (1749-1817) Earth started out as a vast blob of material dispersed in water. Primitive Rocks - plutonic igneous rocks and most metamorphic rocks. Stratified Formations- sedimentary rocks and volcanic rocks

Front 43

Vulcanist View

Back 43

James Hutton (1726-1797). Inherently hot planet with rocks forming from the fusing of particles by heat, or from solidification of magma rising from the interior. Primitive rocks did not necessarily come first.

Front 44

Difference between lava and magma

Back 44

lava is molten material ejected from a volcano; magma is molten material below Earth's surface

Front 45

pyroclastic materials

Back 45

lava fountain blobs, ash, pumice
What shoots out of the volcano when it erupts.

Front 46

Framework for naming igneous rocks:

Back 46

composition (minerals present) and texture (size of mineral grains)

Front 47

How to categorize magma and igneous rocks:

Back 47

Felsic, Intermediate, Mafic, Ultramafic

Front 48

Mafic and Ultramafic mostly contain..

Back 48

magnesium rich and iron rich silicate minerals, olivine and pyroxene. Produce dark gray to black rocks.

Front 49

Intermediate rocks...

Back 49

contain hornblende, biotite, or pyroxene and plagioclase feldspar. Gray shades are most typical.

Front 50

Felsic Rocks...

Back 50

contain quartz, sodium rich plagioclase feldspar, and potassium feldspar with minor dark minerals. The lightest in color.

Front 51

aphanitic texture..

Back 51

magma cools quickly and rock consists of very small crystals generally invisible to naked eye

Front 52

obsidian texture..

Back 52

felsic volcanic glass with dark gray to black color, despite felsic composiiton, lots of dispersed tiny magnetite grains make it dark. Formed at surface of lava flows.

Front 53

phaneritic texture...

Back 53

magma cools slowly where warm rocks surrounds and insulates it deep beneath the surface, mineral crystals grow very slowly produce this coarse grained texture.

Front 54

porphyritic texture...

Back 54

magma starts to crystalize slow at depth but moves into colder environment and crystallizes fast. Some large crystals and some small crystals.

Front 55

bombs

Back 55

largest pyroclastic fragments

Front 56

lapilli

Back 56

intermediate sized pyroclastic fragments

Front 57

volcanic ash

Back 57

smallest sized pyroclastic fragments

Front 58

ultramafic and phaneritic peridotite composes...
igneous rocks

Back 58

Earth's mantle and pieces of this rock are sometimes carried to the surface at erupting volcanoes.

Front 59

Basalt and grabbro form from..
igneous rocks

Back 59

mafic magma and contain the same minerals but have different textures. gabbro course grained. Oceanic crust composed mostly of these mafic rocks.

Front 60

Andesite and diorite
igneous rocks

Back 60

solidify from intermediate composition magmas

Front 61

Rhyolite and granite
igneous rocks

Back 61

form from the most felsic magmas

Front 62

Dacite and tonalite
igneous rocks

Back 62

have compositions that fall between andesite and rhyolite

Front 63

pumice is...
pyroclastic deposits

Back 63

lightweight highly vesicular lapilli, dacitic or rhyolite in composition

Front 64

cinder is...
pyroclastic deposits

Back 64

basaltic or andesitic

Front 65

Igneous rocks are used for...

Back 65

construction and industry, make good building stone,

Front 66

Most volcanoes are found at or near..

Back 66

divergent and convergent plate boundaries. Exceptions: hot spots like yosemite

Front 67

rock melting depends on..

Back 67

temperature, pressure, minerals present in rock, and water

Front 68

fractional crystallization
igneous rocks

Back 68

the melt changes composition through time because minerals that form early during crystallization differ in composition from the magma and separate from it.

Front 69

assimilation
igneous rocks

Back 69

magma rises toward the surface comes into contact with the surrounding rock, these rocks might partially or completely mix into the magma, changing it's composition.

Front 70

key to understanding volcanic phenomena:

Back 70

gas content and viscosity

Front 71

viscosity

Back 71

resistance to flow
low viscosity = water
high viscosity = tar, cake batter

Front 72

basaltic eruptions...

Back 72

are usually not explosive and porphyritic

Front 73

andesitic, dacitic, and rhyolitic volcanoes

Back 73

have more pyroclastic materials than basaltic eruptions, more explosive

Front 74

pegmatite
igneous rock

Back 74

economically important, forms very late in the crystallization of intrusions, very large crystals, forms from high fluid content. because they crystallize last they are enriched with elements that were excluded from typical rock forming silicates, they are right with rare minerals and exotic elements

Front 75

The most common rocks on Earth's surface are...

Back 75

sedimentary rocks

Front 76

physical weathering: the different processes that make it happen

Back 76

water freezing and expanding inside the rock, salt water gets into the rock and then the water dries up leaving salt crystals which break the rock apart, root growth, fluctuating air temps cause minerals to change volume break apart.

Front 77

chemical weathering: the processes that make it happen

Back 77

dissolution: minerals breaking down into water, hydrolysis- consumes mineral and water molecules while reorganizing elements

Front 78

carbon dioxide and water
sedimentary rocks section

Back 78

make the most abundant acid in chemical weathering

Front 79

oxidation
sedimentary rock section

Back 79

process by which substances react with oxygen to form new substances by exchanging electrons.

Front 80

clastic sediment

Back 80

residue of particles that remain after rocks weather, these particles are the physically weathered parts of the original rock along with minerals such as clays that form by chemical weathering

Front 81

Which mineral is the most resistant to weathering?

Back 81

Quartz because of it's lack of iron and strong covalent bonds
(silicate minerals are more resistant to chemical weathering)

Front 82

chemical sediment

Back 82

most ions dissolved in water eventually precipitate as solid ionic compounds

Front 83

how to make a sedimentary rock

Back 83

compaction decreases volume of pore spaces and packs grain closer together, stray charges on clay mineral outer surfaces help compact and asymmetry of water molecule. Cementation: pore spaces fill with precipitated minerals that glue grains together; calcite, quartz, clay minerals, hematite the most common.

Front 84

how to classify a sedimentary rock

Back 84

texture (grain size) composition
clastic, chemical, biochemical (biogenic)

Front 85

sorting
clastic sedimentary rocks

Back 85

describes the range of grain sizes. well sorted contains mostly one grain size while poor sorted contains many sized grains

Front 86

classification of clastic sediment
clastic sedimentary rocks

Back 86

gravel, sand, and mud

Front 87

rounding
clastic sedimentary rocks

Back 87

angular, rounded

Front 88

quartz
arkose
and lithic sandstones
(clastic sedimentary rocks)

Back 88

quartz sandstone is made completely of quartz
arkose sandstone is at least 25% feldspar
lithic sandstone consists of sand size rock fragments

Front 89

the most abundant rocks formed by chemical precipitation
chemical sedimentary rocks

Back 89

limestone - calcite
chert- quartz

most chemical sedimentary rocks are overwhelmingly composed of one mineral

Front 90

rock salt and rock gypsum are commonly referred to as...
chemical and biogenic sedimentary rocks.

Back 90

evaporites.
to emphasize formation in arid lagoons or drying desert lakes where evaporation allows precipitation of halite and gypsum

Front 91

clastic sedimentary rocks are as followed:

Back 91

breccia- if fragments are angular
conglomerate- if fragments are rounded (gravel)
sandstone (sand)
mudstone, claystone,siltstone and shale (silt, mud, clay)

Front 92

chemical sedimentary rocks are as followed:

Back 92

limestone (calcite)
dolostone (dolomite)
chert (quartz)
rock salt (halite)
rock gypsum (gypsum)
coal (plant organic matter)

Front 93

graded beds
sedimentary rocks

Back 93

sediment grain size uniformly changes from coarser at the base of a bed to finer at the top

Front 94

rocks exhibit two types of metamorphic change...

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new minerals form at the expense of the original ones because of chemical reactions and the rock texture is altered by changes in size, shape, and orientation of minerals

Front 95

three processes most commonly cause heat transfer to rocks so they experience high temperature.

Back 95

sediment burial
tectonic burial
magma intrusion

Front 96

normal stress
and
shear stress
(metamorphic rocks)

Back 96

norman stress is force applied perpendicular to a surface.
shear stress describes force applied parallel to a surface.

Front 97

recrystallization
metamorphic rocks

Back 97

is a metamorphic process that changes the size and shape of existing minerals rather than making new minerals (transfer of atoms to one part of a crystal from another part)