Science Final

Final notes

What is a mineral?

naturally, occuring, inorganic crystalline material with a unique chemical composition

What are the tests of a mineral properties?

Streak, color, luster, crystal shape/habit, mineral strength, cleavage, fracture, density,

luster

quality of light reflected from the surface of a mineral

streak

color of mineral in powdered form

habit

shape of crystal

hardness

the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale

cleavage

the state of being split or cleft

fracture

any break or rupture in rock along which no appreciable movement

density

the amount per unit size

silicate minerals

four oxygen ions

feldspar

any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium

what is quartz?

common silicate mineral

dark silicate minerals

contain ions of iron and magnesium/dark

what is confining pressure

pressure applied equally on all surfaces

what is differential stress

difference between the greatest and least compressive stress

difference between confining pressure and differential stress

conf.-forces in different directions/diff.-forces applied equally

divergent plate boundaries?

plates move apart

convergent plate boundary

two plates move together

oceanic convergence

when two oceanic slabs converge, one descends beneath the other, volcanic activity

volcanic island arc

arc shaped chain of volcanic islands

continental convergence

one landmass moves toward the other bc of subduction of seafloor

continental drift

the gradual movement and formation of continents

plate tectonic theory

earth's outer shell consists of individual plates that interact in various ways and thereby create formations

elastic rebound theory

accumulation and release of stress and strain, causing a shake due to elasticity

what are the types of lava

basaltic, rhyolitic, aa, pahoehoe, pillow

basaltic lava

made from mafic/fluid, very fast

rhylotitic lava

felsic/slow

aa flow

rough jagged lava chunks

pahoehoe

freely flowing lava

how does pahoehoe turn into aa?

gas bubbles in the lava pop and turn into spikes, molten interior advances and outer crust is broken

pyroclastic flow

chaotic mix of rock, gas, and ash

dip slip faults

primarily parallel to the slope

normal fault

an inclined fault in which the hanging wall appears to have slipped downward relative to the footwall

reverse faults

dip slip faults in which the hanging block moves up relative to the footwall block

thrust fault

a geological fault in which the upper side appears to have been pushed upward by compression

strike slip fault

dominant displacement is horizontal and parallel to the trend of the fault surface

epicenter

the point on the Earth's surface directly above the focus of an earthquake

foreshock

a tremor preceding an earthquake

aftershock

a tremor occurring after the main shock of an earthquake

karst topography

a landscape with numerous caves and sinkholes and underground steams

water table

underground surface below which the ground is wholly saturated with water

porosity

the property of being porous; being able to absorb fluids

aquitard

semipervious nature that transmits water slower than an aquitard

aquifer

underground bed or layer yielding ground water for wells and springs etc

stalactite

a cylinder of calcium carbonate hanging from the roof of a limestone cave

stalagmite

a cylinder of calcium carbonate projecting upward from the floor of a limestone cave

spring

occurs when water pressure causes a natural flow of groundwater onto the earth's surface

shield volcano

shape of a broad, slightly domed structure that ressembles a warrior's shield

cinder cones

ejected lava fragments that begin to harden in flight to produce scoria, rock.

composite volcanoes

pitersque, yet dangerous. composed of both lava flows and pyroclastic material

composite volcano shape

conical shape

cinder cone shape

steep sided, deep craters

cinder cone eruption

short lived, magma plumbs connecting vent to magma source solidifying