Andesitic Lava Flow

Felsic - Rhyolite

Intermediate - Andesite

Mafic - Basalt

Felsic - Granite

Intermediate - Diorite

Mafic - Gabbro

Eruption that is location in the summit crater. Basically, an eruption from the middle top of the volcano.

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Eruption from the side of the volcano from a fissure that cuts in the side of the volcano mountain

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Broad, Slightly dome shaped, made by MAFIC flows

Think of a football dome stadium, except less gay

Smallest type of Volcano

Made only of pyroclastic debris (tephra)

Built of ejected lapilli-sized fragments

Very softly angled

Large, Cone-Shaped Volcano

Made of alternating layers of lava and tephra

Often Symmetric

This is the general volcano that you think of when you think of a volcano

Lava Flow

Commonly Basaltic/Mafic

Can create shield volcanoes

Blows up

Caused by gas pressure in more viscous magma

This creates stratovolcanoes

May create calderas

Can blanket the landscape with Tephra

FELSIC and INTERMEDIATE

Most lava erupts here

MOR crust covers 70% of earth

Basalt erupted from fissures gets quenched by water and turns into pillows

Most Volcanoes form along these, but most ERUPTIONS still at Mid-Ocean Ridges

They Don't Move

Plates move over hot spots. But still, HOT SPOTS DON'T FUCKING MOVE

Results in trails of volcanoes

Makes islands

Clastic - Made from weathered rock fragments or clasts

Biochemical - Cemented shells of organism

Organic - Made from carbon-rich remains of plants

Chemical - Minerals that crystallize from water

Weathering - Generation of Detritus via rock disintegration

Erosion - Removal of sediment grains from rock

Transportation - Dispersal by wind, water, and ice

Deposition - Settling out of transporting fluids

Lithification - Transformation into solid rock

Lithification - Happens when enough tiny sediments come together to create a bigger rock

Burial - When more sediment is added onto previous

Compaction - Overburden weight reduces pore spaces

Cementation - Minerals grow in pores - gluing the sediments 

Usually coarser and poorly sorted and angular

COURSE CLASTS

Breccia 

Well-Sorted, Rounded, and fine-grained

Breccia - Coarse, Angular

Conglomerate - Coarse, Rounded

Sandstone - Fine

Silt Sized - Even Finer (SILTSTONE)

Clay Sized - Finest (SHALE)

Coal - Altered remains of fossil vegetation (dead plants)

Oil Shale - Shale mixed with heat altered organic matter

Always have to do with water

Evaporites - Created from Evaporated seawater

Halite and Gypsum

Travertine - Comes from groundwater that reaches the surface

Near Deposition

-Layering

-Surface features on Layers

-Arrangement of Grains

A whole series of beds of sed. rocks

Recognized on a Regional Scale

Larger version of Ripples

A giant pile of sand. GIANT.

Sometimes it is hard. Sometimes it is soft.

Often preserve cross-laminations

Mud Cracks - Cracks in wet mud

Scour Marks - Troughs eroded in soft mud by current flow

Trace Fossils - Evidence of past life

-Footprints

-Impressions are examples

Due to movement of ice

Carries and dumps every grain size

Glacial Till - Poorly sorted (all kinds of sediments)

Carry large clasts during floods

During low flow, these cobbles and boulders are immoble

Conglomerate is a characteristic of this setting

COMES DOWN THE MOUNTAIN...when she comes...haha...comes

Sediments that pile up at the foot of a mountain

Rapid drop in stream velocity creates a cone shaped wedge

Sediments are immature conglomerates and sandstones

Wind blown piles of well sorted sand

Move according to prevailing winds

Result in uniform sandstones with gigantic cross beds

Channelized Flow transports sediment

ONLY fine sand, silt, and clay

Gravels and sands are trapped NEAR SHORE

Well-sorted muds deposited in deeper water

Often capped with wetland muds

Sediments dropped where a river enters the sea

Sediment carried by river, dumped when velocity drops

Deltas grow over time because the water cuts land masses by erosion

Coastal Beaches (Surf Zone)

Sediments constantly processed by wave attack

Well-Sorted, Well-Rounded Medium Sand

Finer version of beach sediment

Fine silt and muds turn into siltstones and mudstones

Usually support life

Reefs

Warm, clear, shallow, normal salinity, marine water

BIOCHEMICAL

Skeletons of plankton organisms make chalk or chert

Fine silts and clays turn to shale

Temperature

Pressure

Tectonic Stress

Reaction with Heated Water

1. Recystallization - Minerals change size and shape

2. Phase Change - New minerals Form

-Same chemical formula

-Different Crystal Structure

3. Neocrystallize - New minerals with changes in temp and pressure

Range: 200c to 850c

Sources of Heat:

Geothermal Gradient

Magmatic Intrusions

Compression

Increases with Depth

Temp and Pressure BOTH change with depth

Mineral Stability is HIGHLY dependent on Temp and Pressure

Changes in these two lead to changes in minerals

Pressure that is greater in one orientation

A commonplace result of tectonic forces

Normal Stress - Operates perpendicular to a surface

-Tension - Pull apart

-Compression - Push together

Shear Stress

-Operates sideways across a surface

-Causes material to be "Smeared out"

Think peanut butter on bread

Imparts a layered or banded appearance

Develops perpendicular to compression

-Minerals flatten, recrystallize, and rotate

-Rocks commonly break parallel to foliation planes

No Bands

No differential Stress

FOLIATED

Fine-Clay, Low Grade

FOLIATED

Fine, Mica-Rich

LOW TO MEDIUM GRADE

FOLIATED

MEDIUM TO HIGH GRADE

Fine or coarse with large micas

FOLIATED

Distinct Banded Foliation

Light bands are felsic

Dark bands are mafic

RELATIVELY HIGH PRESSURES AND TEMPS

NONFOLIATED

NONFOLIATED

Made of Limestone

Shale Protolith

Clays make a Slate

Micas make a Phyllite

Micas make Schist

New minerals grow in the schist

Thermal - Heated by a plutonic intrusion

Burial - Increases Pressure and Temp by deep burial in a basin

Dynamic - Shearing in Fault Zone

Regional - Pressure and Temp alteration due to Orogenesis

Hydrothermal - Alt. by Hot water leaching

Subduction - High pressure, low temp alteration

Shock - Extremely high pressure

Also called Contact/Aureole

Dominant Rock is HORNFELS

Shallow Crust - Upper 10-15 KM

Brittle Rocks

Mineral Grains Crush/Forming Fault BRECCIA

Deeper Crust - Below 10-15 KM

Minerals smear like taffy to form MYLONITE

Tectonic Collisions form mobile belts

Rocks in regional metamorphism are

-Heated via geothermal gradient

Squeezed and heated by burial

-Smashed and sheared by differential stress

REGIONAL MAKES FOLIATED ROCKS

Alteration by hot chemically-aggressive water

Dominant by mid-ocean ridges

High pressure/Low Temp

Rock created in trenches

Footwall - Always Obtuse Angle

Hanging Wall - Always Acute Angle

Most faults are this

Combination of Dip-Slip and Strike Slip (Transform)

Pure D-S and S-S are rare

Pass through earth's interior

P - Compressional

Push Pull

Travel through solids/liquids/gases

FASTEST

Travel through all layers

Vibrate the same direction they move

Like a Slinky

Shear or Secondary Waves

Shaking Motion

ONLY SOLIDS, NOT LIQUIDS

Moves like an "S"

Slower than P

Travel only along earths surface

Move back and forth like a snake

SURFACE WAVE

SURFACE WAVE

Moves in a circular/pond ripple motion

Slowest and most destructive

0-20 KM

Along Mid-Ocean Ridges

Lower Magnitude

Continental Crust

Transform Boundaries

Intermediate

Deep

Inter - 20-300 KM

Still brittle

Deep 300-670 KM

Minerals Transform

Earthquakes rare below 670 km

Great Chile Earthquake

9.5 on Richter

May 22, 1960

Earthquake on Continental Crust

Continental Transform Faults - San Andreas in SF

Continental Rifts - Basins and Ranges

Collision Zones - Large Mountains

Intraplate Settings - Ancient crustal weakness

Near San Francisco

Hundreds of Earthquakes per year

Strike-Slip

Not Well Understood

Not on plate boundary

5% of Earthquakes

Bedrock transmits waves quickly - Less Damage

Sediments Bounce Waves - Amplified Damage