Geos 2104 test 2

What processes create igneous rocks?

Magma can crystallize at at depth or at the Earth's surface

What kind of igneous rocks form at depth?

Plutonic Rocks (intrusive)

What kind of igneous rocks form at the Earth's surface?

Volcanic Rocks (extrusive)

Define Magma

Molten rock

Where do igneous rocks form?

Volcanoes at plate boundaries

Define hot spot

a location where volcanoes form due to deep magma rising to form volcanoes

Where are some hot spots?

Hawaii

Where in the US are volcanoes?

Hawaii (Hot spot)

Alaska (Bering and NA plates)

West Coast (Subduction of a plate under NA)

Yellowstone

Southwest (Extension)

Define Felsic (color and rich in what elements)

light (color)

Name some felsic minerals

Quartz

Name some intermediate minerals

Plagioclase Feldspar

Define Mafic (color

rich in what elements?)

Name some mafic minerals

Pyroxene

Plagioclase Feldspar

Define Ultramafic

Darkest

Name some ultramafic minerals

Olivine

What is the composition of the oceanic crust?

Mafic

What is the composition of continental crust?

Felsic

Do mafic or felsic minerals crystallize first

Mafic

Do mafic or felsic minerals melt first

Felsic

Partial melt of an ultramafic rock produces magma of what composition?

Mafic magma

Partial melt of an ultramafic rock produces magma at what tectonic settings?

Spreading centers

Partial melt of a mafic rock produces magma of what composition and at what tectonic setting?

Felsic magma at subduction

What makes volcanic rocks different from plutonic rocks?

Fast cool

What makes plutonic rocks different from volcanic rocks?

Slow cool

Describe granite

Plutonic

Describe rhyolite

Volcanic

Describe diorite

Plutonic

Describe andesite

Volcanic

Describe gabbro

Plutonic

Describe basalt

Volcanic

Describe Peridotite

Plutonic

Define viscosity

Ability to resist flow

Does felsic of mafic magma have a higher viscosity?

Felsic

Define lava flow

Flowing lava

What shape of volcano does lava flow produce? Why?

Shield Volcano. Mafic magma crystallizes first

Define Fissure Eruption

The lava comes from cracks instead of mountains

What is a pillow basalt and where is it formed?

Underwater lava flow cools and forms bubbles

Define Pyroclastic Eruption

Explosion due to high viscosity

What kind of volcano do pyroclastic eruptions form?

Cinder cone

What kind of volcano does a mix of lava flows and pyroclastic eruptions form?

Composite cone

What is ash?

Small chunks of debris

What is bomb?

Large chunks of debris

What is pyroclastic flow (nuees ardente)?

Flow of super hot ash

What is lahar?

A mix of ash and water (mud flash flood)

What is lava?

Magma on the Earth's surface (very slow)

What does volcanic rock and ash produce?

Rich soil

What is one plutonic intrusion effect?

Creation of igneous rocks

What are some shapes of plutonic intrusions?

Volcanic neck

Define Permeability

The ability of a material to let water pass through it

Where on Earth are sedimentary rocks made?

Everywhere

Define Weathering

The breaking down of rocks

Define erosion

To gradually wear away with the movement of wind

Define Clast

Grain size

Define deposition

When sediment is moved somewhere

Describe the lithification process

Sediment is compacted and the cemented together to form a rock

Define Clastic sedimentary rock

Made when pieces of rock

What is the most common mineral in clay?

Feldspar

What is the most common mineral in sand?

Quartz

What environments result in poor sorting?

Landslide

What environments result in good sorting?

Water slows gradually

What sediment makes conglomerate?

Gravel

What sediment makes sandstone?

Sand (10% of sedimentary rocks)

What sediment makes shale?

Clay (70% of sedimentary rocks)

How is limestone formed?

Calcium carbonate is compressed (calcite

What is chert and what is it made of?

Flint (Quartz)

What are the fossil fuels and how are they formed?

Coal

What is evaporite?

A type of sedimentary deposit resulting from the evaporation of seawater (salts

What is bedding?

layering in sedimentary rocks

What are strata?

layers of sedimentary rock

What is stratigraphy?

Analysis of layered sediment deposits

What sedimentary rocks are most likely to form in a landslide?

Conglomerate (Poorly sorted boulders

What sedimentary rocks are most like to form in glaciers?

Conglomerate (Poorly sorted mechanical)

What sedimentary rocks are most likely to form in deserts (wind-blown)?

Sandstone (Sand

What sedimentary rocks are most likely to form in deserts (evaporation)?

Evaporite (Chemical)

What sedimentary rocks are most likely to form in wind-blown dusty soils?

Loess

What sedimentary rocks are most likely to form in rivers?

Limestone

What sedimentary rocks are most likely to form in the mouth of a river?

Shale

What sedimentary rocks are most likely to form in a swamp?

Coal

Sediments cover what % of the surface of the continents?

70%

Is shale strong or weak? hard or easy to erode?

Weak

Is sandstone strong or weak? hard or easy to erode?

Strong

Is limestone strong or weak? hard or easy to erode?

Strong

How are sedimentary rocks used for construction?

Gravel

Describe the permeability and porosity of shale

Medium porosity

Describe the permeability and porosity of sandstone

High porosity

Describe the permeability and porosity of limestone

Irregular porosity

Describe the permeability and fertility of clay

Fertile

Describe the permeability and porosity of sand

Not fertile

Describe Metamorphism

Change of shape/form (Heat+Pressure+Fluid Chemistry)

What is the Parent Rock?

Original rock before metamorphism

What is metasomatism?

Change of chemical composition by fluids

How/where does regional metamorphism occur?

Temperature and pressure

How/where does contact metamorphism occur?

Heat from contact

How/where does dynamic metamorphism occur?

Pressure/(Fluid chemistry)

How/where does hydrothermal metamorphism occur?

Fluid chemistry/(Heat)