Geol1104, Chapter 1-4

Front 1

general characteristics of magma

Back 1

-parent material: igneous rocks
-forms from partial melting of rocks
-magma at surface is lava

Front 2

igneous rocks

Back 2

forms as molten rock cools and solidifies

Front 3

extrusive, volcanic rock

Back 3

rocks formed from lava
(basalt)

Front 4

intrusive, plutonic rocks

Back 4

rocks formed from magma at depth
(granite)

Front 5

nature of magma

Back 5

-liquid portion = melt
-solids, if any are silicates
-volatiles = dissolved asses in the melt (h2o, co2,so2)

Front 6

factors affecting crystal size

Back 6

-rate of cooling
-% of silica (SiO4) present
-dissolved gases

Front 7

slow rate of cooling

Back 7

fewer but larger crystals

Front 8

fast rate of cooling

Back 8

many small crystals

-if really fast cooling, gasses are formed

Front 9

aphanitic

Back 9

fine-grained texture
rapid rate of cooling
microscopic crystals
many contain vesicles (holes,bubbles)

Front 10

phaneritic

Back 10

coarse-grained texture
slow cooling
large, visible crystals

Front 11

porphyritic texture

Back 11

-minerals form at different temperatures
-large crystals (phenocrysts) are embedded in smaller crystals

Front 12

glassy texture

Back 12

-very rapid cooling of lava
-resulting rocks are obsidian

Front 13

pyroclastic texture

Back 13

-fragmental appearance produced from violent volcanic eruptions
-appear similar to sedimentary rocks

Front 14

pegmatic texture

Back 14

-exceptionally coarse grained
-form in late stages of crystallization of granitic magmas

Front 15

granite composition

Back 15

-light colored silicates
-termed felsic
-high amounts of silica
-major constituent of continental crust

Front 16

basaltic composition

Back 16

-dark silicates and calcium rich feldspar
-termed mafic
-higher density than granitic rocks
-comprise the ocean floor and volcanic islands

Front 17

granite

Back 17

-phaneritic
-over 25% quartz, 65% feldspar
-abundant

Front 18

rhyolite

Back 18

-extrusive equivalent of granite
-may contain glass fragments and vesicles
-aphanitic texture
-less common and less voluminous than granite

Front 19

obsidian

Back 19

-dark colored
-glassy texture

Front 20

pumice

Back 20

-volcanic
-glassy texture
-frothy appearance with numerous voids

Front 21

magmatic differentiation

Back 21

separation of a melt from an earlier formed crystals

Front 22

assimilation

Back 22

changing a magmas composition by the incorporation of surrounding rock bodies into a magma

Front 23

lithosphere

Back 23

-strong, rigid outer layer
-upper mantle and crust
-overlies a weaker region in the mantle called asthnosphere

Front 24

divergent boundaries

Back 24

-most are located along the crests of oceanic ridges
-oceanic ridges/seafloor spreading

Front 25

convergent boundaries

Back 25

older portions of oceanic plates are returned to the mantle in destructive plate margins
-subduction zones

(ocean-continental, ocean-ocean, continental-continental)

Front 26

transform fault boundaries

Back 26

plates slide past one another and no new lithosphere is created or destroyed
(san andras,

Front 27

hot spots

Back 27

caused by rising plies of mantle material, volcanos can form over them (hawaii islands)

Front 28

mineral

Back 28

-naturally occurring
-inorganic solid
-ordred internal molecular structure
-definite chemical composition

Front 29

rock

Back 29

a solid aggregate of minerals

Front 30

element

Back 30

-basic building blocks of minerals
-over 100 are known, 92 occur naturally
(close too 120 known elements)

Front 31

atoms

Back 31

-smallest particles of matter
-retains all the characteristics of an element

Front 32

electrons

Back 32

negatively charged particles that surround the nucleus
(located in shells)

Front 33

nucleus

Back 33

protons(positive)
neutrons (neutral)

Front 34

atomic number

Back 34

# of protons in the nucleus

Front 35

atomic mass

Back 35

# of protons and neutrons

Front 36

atomic weight

Back 36

average of masses

Front 37

chemical bonding

Back 37

formation of a compound by combining two or more elements

Front 38

ionic bonding

Back 38

atoms gain or lost outermost (valence) electrons to form ions

Front 39

covalent bonding

Back 39

sharing of electrons to achieve neutrality

Front 40

polymorphs

Back 40

minerals with the same composition but different crystalline structures
(diamond and graphite)

Front 41

mineral identifying properties

Back 41

crustal form, luster, color, streak, hardness, cleavage

Front 42

rock forming minerals

Back 42

common minerals that make up most of the rocks of earth's crust. mainly composed of 8 elements that make up over 98% of the continental crust

Front 43

silicates

Back 43

most important mineral group
-most common rock forming minerals
-very abundant due to large & of Si and O in earths crust

Front 44

silicon-oxygen tetrahedron

Back 44

-fundamental building block
-4 oxygen ions surrounding a much smaller silicon ion

Front 45

most abundant silicon in earths crust

Back 45

feldspar
(quartz is 2nd most)

Front 46

physical geology

Back 46

examines the materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface

Front 47

historical geology

Back 47

seeks an understanding of the origin of Earth and its development through time

Front 48

law of superposition

Back 48

In an undeformed sequence of sedimentary rocks, each layer is older than the one above it and younger than the one beneath it.

Front 49

law of faunal succession

Back 49

Fossil organisms succeed one another in a definite, determinable order.

Front 50

index fossils

Back 50

-geographically widespread
-easily recognized
-restricted to a specific interval in geological time

Front 51

earths 4 spheres

Back 51

-hydrosphere
-atmosphere
-biosphere
-solid earth

Front 52

layers defined by composition

Back 52

-crust
-mantle
-core

Front 53

layers defined by physical properties

Back 53

-lithosphere
-astehenosphere
-mesosphere
-inner and outer core

Front 54

ocean ridge system

Back 54

-most prominent topographic feature on earth
-composed of igneous rocks that has been fractured and uplifted

Front 55

sedimentary rocks

Back 55

-accumulate in layers of earths surface
-sediments are derived from weathering of preexisting rocks
(sandstone and limestone)

Front 56

metamorphic rocks

Back 56

-formed by "changing" preexisting igneous, sedimentary or other metamorphic rocks
-driving forces are increased heat and pressure
(gneiss and marble)

Front 57

inner core

Back 57

liquid

Front 58

catastrophism

Back 58

belief that earth's landscapes had been shaped primarily by great catastrophes.

Front 59

relative dating

Back 59

events are placed in their proper sequence or order without knowing their age in years

Front 60

nebular hypothesis

Back 60

bodies of our solar system evolved from an enormous rotating cloud called the solar nebula

Front 61

transition zone

Back 61

mid mantle

Front 62

lower mantle

Back 62

lower mantle to top of core

Front 63

core

Back 63

inner most part of earth--iron and nickel
-outer is liquid
-inner is solid

Front 64

seafloor spreading

Back 64

oceanic ridges are located above zones of convection which cause movement

Front 65

plate tectonics

Back 65

composite of a great variety of ideas that explain the observed motion of earth's outer shell though the mechanisms of subduction and seafloor spreading

Front 66

7 major lithosphereic plates

Back 66

north american
south american
pacific
african
eurasian
austrailian-indian
antarctic