Geology Exam 1

Front 1

Why is it important to understand history of Earth?

Back 1

1. origin/ev. of life

2. formation of natural res.

3. effects of geologic hazards

4. cc

5. ev. of other planets

Front 2

What is a hypothesis?

Back 2

Statement designed to explain set of ob.; able to predict ob., must be FALSIBLE; good hypothesis explains ALL existing ob.

Front 3

What are the two definitions of science?

Back 3

1. body of knowledge related to the study of natural phenomenon

2. application of scientific method--gather facts, form hypothesis, eval. hypotheses (test)

Front 4

What's a theory?

Back 4

Well tested, widely accepted hypothesis; explain observational facts; all theories are provisional

Front 5

What is the nebular hypothesis?

Back 5

Rotating cloud called the solar nebula made of hydrogen/helium began to contract 5mya,_________________

Front 6

What is chemical differentiation?

Back 6

Creates layered Earth, lighter on outside, denser inside

Front 7

Name the COMPOSITIONAL layers of Earth from inside to out. Then name mechanical layers inside to out.

Back 7

Core, crust, mantle; mechanical = Inner/outer core, lower mantle, asthenosphere, lithosphere

Front 8

Define catastrophism and uniformitarianism.

Back 8

Cat--earth's landscapes were shaped primarily by catastrophes; Unif--the physical, chemical and biologic laws that operate today have operated in the geo. past

Front 9

Under stand the rock cycle.

Back 9

See chart.

Front 10

Plate tectonics is concerned with motion of what layer of Earth?

Back 10

Lithosphere

Front 11

Describe relative motion, topography, volcanic activity, and earthquake depth of a DIVERGENT boundary.

Back 11

Plates separate, new seafloor made;

Front 12

Describe relative motion, topography, volcanic activity, and earthquake depth of a CONVERGENT boundary.

Back 12

plates collide, subduction of oceanic plate into mantle; volcanic arcs,

Front 13

Describe relative motion, topography, volcanic activity, and earthquake depth of a TRANSFORM boundary.

Back 13

slide past each other;

Front 14

List and describe forces driving plate motion.

Back 14

Slab pull: convergent

Ridge push: divergent

Mantle convection: plates move in circular motion

Front 15

The characteristics of a mineral include:

Back 15

1. Naturally occurring

2. Inorganic solid

3. Ordered internal mol. structure

4. Definite chemical comp.

Front 16

Name the 3 forces that are the sources of Earth's heat.

Back 16

Collisions, compression, radioactivity

Front 17

Name the three kinds of chemical bonds.

Back 17

1. Ionic = Atoms gain/lose electrons to form ions; orderly arrangement with oppositely charged ions

2. Covalent = SHARE electrons, stronger than ionic; happens in same as ionic though

3. Metallic = valence elec. free to migrate among atoms; weaker and less common

Front 18

What do the atomic #, atomic mass, and isotopes tell you?

Back 18

Mass = number of protons and neutrons

Number = numbers of protons

Isotopes = same element with different mass, same atomic number

Front 19

List the physical prop of minerals

Back 19

Crystal form

Luster

Color

Streak

Hardness

Fracture

Spec. Gravity

Front 20

What two elements are most abundant in continental crust?

Back 20

Oxygen and silicon

Front 21

Silicate structures

Back 21

_________________

Front 22

Igneous rocks can be ____ and ____.

Back 22

Extrusive; cooled at or near surface

Intrusive; cooled beneath surface

Front 23

What is the steep part of the geothermal gradient representative of? What do the curves mean?

Back 23

Convection in the mantle; curves are explained by conduction

Front 24

How is magma generated?

Back 24

1. Heating rocks above melting point

2.Lowering melting point by decreasing pressure OR adding volatiles

Front 25

What does magma contain?

Back 25

Molten rock that has suspended crystals and dissolved gases such as water vapor, CO2 and sulfur dioxide

Front 26

What is assimilation?

Back 26

Changing of a magma's composition by incorporating surrounding rocks bodies

Front 27

Magma Mixing is?

Back 27

combining two compositionally distinct magma

Front 28

Describe the discontinuous reaction series.

Back 28

Olivine to pyroxene to amphibole to biotite

Front 29

Describe the CONTINUOUS reaction series.

Back 29

Ca-Rich Plagioclase to Na-Rich Plagioclase

Front 30

What factors control the texture of igneous rocks?

Back 30

Rate of Cooling = slow is large, fast is small crystals

Amount of Silica =

Amount of dissolved glasses

=

Front 31

What are the three textures of igneous rocks.

Back 31

1. aphanitic (ex. Rhyolite) very small crystals; fine grained

2. phaneritic; crystals can be seen; coarse grained (Granite)

3. porphyritic; large crystals in a finer grained matrix (looked mixed)

4. Glassy; lacks crystals because of rapid cooling (Obsidian)

5. Vesicular; many elliptical cavities formed by gas bubbles in rock (Pumice)

Front 32

Concordant is ?

Back 32

Sills, laccoliths; runs parallel to pre-existing rock

Front 33

Discordant is ?

Back 33

Dikes, batholith; cuts across pre-existing rock

Front 34

Where can volcanic/plutonic activity occur?

Back 34

1. Hotspots (Hawaii, yellowstone)

2. Convergent margins within volcanic arc (South American Andes)

3. Divergent margins at mid-ocean ridge

Front 35

What determines viscosity of magma?

Back 35

1. Temp of magma

2. Composition of magma

3. Dissolved gases in magma

In turn this controls nature of an eruption

Front 36

What factors effect viscosity?

Back 36

1. Composition - SiO2 content

2. Temp

3. Amount of dissolved gases

Front 37

Name and describe the 2 kinds of basaltic lava flows.

Back 37

1. Pahoehoe flows; have smooth surfaces and resemble twist braids of rope

2. Ah-ah flows; have surfaces of rough jagged rocks

Front 38

List the kinds of magma in order from least to most gas content.

Back 38

Basaltic magma, andesitic magma, rhyolitic magma

Front 39

What's ash fall?

Back 39

fragments ejected into air during eruption; dust-size fragments to meters in diameter

Front 40

What are pyroclastic flows?

Back 40

swiftly moving, turbulent flow composed of gas and rock fragments

Front 41

Describe pumice and scorria.

Back 41

Pumice; light gray or pink porous rock from frothy andesitic rhyolitic lava

Scorria; red-brown porous rock from frothy basaltic and andesitic lava

Front 42

What are the 3 types of volcanoes? Describe.

Back 42

Shield; broad and short; produced by mild eruptions of large volumes of basaltic lava

Cinder Cone; steep slope, occur in groups, made from ejected lava fragments

Composite; classic, large volcanoes

Front 43

What is a caldera and how does it form?

Back 43

A crater larger than 1km in diameter, form by collapse following an explosive eruption

Front 44

Describe the 3 kinds of magma.

Back 44

Basaltic/Mafic; least silica, least gas, least viscosity (shield vol., basalt plateaus, cinder cones)

Andesitic/Intermediate; some silica, kind of viscous, some gas (composite cones)

Felsic/Granitic; most silica, most gas, most viscous (volcanic domes, pyroclastic flows)