geol 106 unit 3

jagged and blocky lava flow

large mass of igneous rock formed when magma at depth is crystalized and then exposed

collapse depression having circular form

• aka scoria cone
• made of dark basaltic lavas and reddish cinders
• usually only erupts once

elongated pillarlike columns formed as igneous rock cools and devlops shrink fractures

• aka stratavolcanoes
• composed of lava and pyroclastic material
• highly explosive

linear fissure in volcano allowing magma to move up to opening

produced when oceanic plate subduct beneath continental plate

funnel-shaped depression at top of volcano

lowering of rock melting temp when confining pressure drops

magma injected into fractures in volcanoes

• bouyant plumes of explosive clouds of ash and gas
• made from highly viscous and silica rich magma

crack in crust

eruption of lava extruded from crack in crust

very fluid lava remaining molten long enough to flow great distances

secondary vents that emit gases

change in temperature with depth

concetration of heat in mantle that produces magma that extrudes to surface

eruptions at interior of plates

volcanism at oceanic convergent plate margin

viscous bulging sill

earthflow of volcanic ash

tunnel in hardened lava acting as horizontal conduit for lava flowing from vent

hotter than normal magma that ascends to surface

fiery pyroclastic flow

smooth twisting lava flow

small volcano formed on side of volcano form side vents

• process of igneous rock melting where mineral melt at different rate
• usually produces high silica magma

magma at depth

hot gases infused with incandescent ash and rock fragments

accumulation of fluid basaltic lava in a broad flat dome shape

tabular plutons when magma injects between sedimentary layers

surface opening of volcano

fluid's resistance to flow

• gaseous components of magma
• especially water

isolated, steep-sided erosional remnant consisting of lava that once occupied volcanic vent

accumulation of sed and meta rocksalong subduction zone

beginning of a subduction zone

upfolding rock

• 3d syncline
• bed rises from core in every direction

fracture once strength is exceeded

change in original shape or size of rock body

movement is parallel to inclination of fault

• 3d anticline
• bed dips away from core in every direction

solid-state flow that producing changes in rocks without fracturing

fractures in crust where displacement has taken place

mntn formed from displacement of rock along fault

exposed areas after fault displacement

wavelike undulation

central block in between normal faults that subsides as plates move

gradual subsidence of mountains caused by lateral spreading of weak material

uplifted structure surrounding graben

floating crust in gravitational balance

establishing of a new graviational equilibrium

fractures in crust without displacement

step-like folds in otherwise horizontal strata

hanging wall moves down

proccesses that build mountains

formation of subdusction zone from same plate

• hanging wall moves up
• dips greater than 45deg

displacement horizontal and parallel to fault

downward fold

any crustal fragment that has distinct geologic history from adjoining rocks

• hanging wall moves up
• dip is less that 45deg

strike=slip fault between large crustal plates

tilted or folded strata overlain with younger flat-laying strata

rock layers deposited without interruption

belief that landscapes formed from catastrophies

matching up rocks of similar age in different regions

fault or intrusion is younger than affected rocks

unconformity where beds abova nad below are parallel

• greatest division of time in geologic time scale
• Precambrian, Phanerozic

• fourth subunit of geologic time
• divides periods

• second subdivision of geologic time
• divides eons
• especially Paleozoic, Mesozoic, Cenozoic

remains or traces of prehistoric life

• fossil organisms succeed each other in a definate and determinable order
• time period can be recognized by fossil content

• division of Earth history
• uses relative dating princliples

time required for half the parent material to decay into daughter material

• pieces of one rock unit contained within another
• contained rock is older

geographically widepread fossils limited to a short span of time thats provides a method of mathching similar aged rocks

break that separates older rock from overalin younger rock

actual number of years that passed since event occured

• layers ore deposited in horizontal pattern
• rocks found otherwise were changed since deposition

study of fossils

• third subdivision of geologic time scale
• divides eras

spontaneous decay of certain unstable nuclei

radiometric dating using carbon-14

• determining actaul age of rocks that contain radioactive isotopes
• uses percentage of parent to daughter material based on know half-life

placing rocks in sequence of formation

each bed is older than the one above it

period where depostion ceased and erosion and/or uplift occured

physical, chemical and biological laws that operate today also occured in the past