Geology Exam 2

Slow moving water only carries

small sediment

Fast moving water carries

both small and large sediment

As water velocity increases

nearby sediment will be eroded (picked up)

As water velocity decreases

nearby sediments will be deposited (set down)

Delta

River deposits all its sediment when water slows down at the coast

order of making sedimentary rocks

1.Weathering

2.Erosion

3.Transport

4.Deposition

5.Lithification/Diagenesis

Recurrence Interval

the average time between successive geologic events

Categories of sedimentary rocks

clastic, organic, chemical, bioclastic

Viscosity

resistance to flow

Mafic

low viscosity

lavas flow long distances

gasses escape easily

effusive eruptions

Felsic

high viscosity

lava stays to vent

gasses build high pressure, escapes all at once

explosive eruptions, eject via debris

Low Viscosity

flows easily

High Viscosity

much more difficult to flow

Magma Viscosity

how resistant a fluid is to flowing

Lava

forms extrusive igneous rocks

Volatiles

gasses, water, like H2O, CO2, SO2, and other hazardous gasses

Ash

very tiny particles of solidified lava, carried far away by atmosphere

Volcaniclastic debris

broken chunks of rocks and lava

Effusive Eruption

lava flows gently down the side

Explosive Eruption

large section of mountain erupts/explodes all at once

Shield Volcano

Mafic magma chamber where there is a gently sloping side and gasses can easily escape

Volcaniclastic debris(describe)

Felsic magma chamber where gasses get trapped and lava doesn't flow far.

Caldera

a large crater caused by the violent explosion of a volcano that collapses into a depression

Pyroclastic flow

avalanche of volcaniclastic debris

Lahar

mix of volcaniclastic debris of water

Transgression(sea level rise)

sea level goes up and depositional environment shifts landward, new deposits are deeper water ,further offshore

Regression(sea level fall)

sea level goes down and depositional environment shifts seaward, new deposits are from shallower water, further onshore

Stratovolcano magma chemical composition

felsic

Stratovolcano igneous rock formed from erupted lavas

rhyolite

Stratovolcano magma viscosity

high viscosity

How far do lavas flow in stratovolcanoes?

Lavas stay close to vent

Shield Volcano magma chemical composition

mafic

Shield Volcano igneous rock formed from erupted lavas

basalt

Shield Volcano magma viscosity

low viscosity

How far does shield volcano lavas flow?

Lavas flow long distance from vent

Stratovolcano dissolved gasses

gasses not easily able to escape

Stratovolcano gas pressure

gas pressure builds up very high

Stratovolcano eruption style

explosive

Shield Volcano dissolved gasses

gasses able to easily escape

Shield Volcano gas pressure

gas pressure never builds up very high

Shield Volcano eruption style

effusive

Stratovolcano erupted material

both lavas and volcaniclastic debris

Stratovolcano resulting volcano shape

volcano has steep slopes

Stratovolcano example plate tectonic context

subduction zone under continental lithosphere

Shield Volcano erupted materials

mostly just gentle lava flows

Shield Volcano resulting volcano shape

volcano has broad gentle slopes

Shield Volcano example plate tectonic context

hot spot under oceanic lithosphere

When the meander is cut off and abandoned by the river, what do you call the remaining body of water?

Oxbow Lake