CH2: THE PHYSICAL ENVIRONMENT Flashcards
innermost layer of the earth
solid inner (iron and nickel)
liquid outer (mostly iron)
super hot (5700K)
Core
middle layer of earth
semi-solid layer that helps transport portions of overlying crust
hot liquid inner
solid outer (more viscous and elastic)
rises and expands when heated, descends when cool
Mantle
solid outer layer; lithosphere
14 major plates
plates are buoyed by mantle movement and the thickness and density of the plate
Crust
the constant motion, moving against, away from, or sliding past of plates
large scale motion plates of the lithosphere
Plate Tectonics
denser, thinner, younger crust
Oceanic Crust
lighter, thicker, granite, older crust
Continental Crust
along mid-ocean ridges where new oceanic crust through volcanic activity
Magma emerges from mantle, fills space, cools as moves away from spreading center
ridges in middle of ocean where magma is below, pushes plates apart
Seafloor Spreading
at convergent boundaries where one plate moves under another and sinks into mantle
where oceanic and continental plates meet (oceanic sinks because heavier)
forms a trench
Subduction
submarine depression on the sea floor where two plates meet
Trench
plates collide
form subduction zones (trenches) or thrust zones (mountains
Convergent Boundaries
denser plate sinks (oceanic)
pressure and friction from subduction melt rock which emerges in cracks along the edge of continental crust as volcanoes
Oceanic-Continental Converging Boundary
similar density; subduction determined by plate size
pressure from subduction melt rock which emerges as volcanoes in cracks along edge of oceanic crust
Oceanic-Oceanic Converging Boundary
plates move apart
form rift zones where new crust is made
Divergent Boundaries
plates slide past in opposite directions
Transform Boundaries
What 2 things between plates can melt crust and create earthquakes?
Friction and Pressure
melted rock heats and expands, working its way through cracks and spaces in the overriding crust in water or through continental crust (volcano)
Magma
Where are oceanic islands commonly formed along?
Subduction Zones
areas of volcanic activity from superheated mantle plumes that melt through overlying plate, forming volcano/island
stationary even with moving plate
creates ISLAND CHAINS that MIGRATE over time bc of HIGH MAGMATIC ACTIVITY
Hotspot Volcanism
When were the Mariana Islands formed?
Cenozoic Era
When was Guam formed?
Mid Eocene Epoch
deposited in layers from different lava flows and eruption events
Volcanic (Igneous) Rock
deposited in layers from different erosion processes with particles of varying sizes and crystal compositions
Sedimentary Rock
type of sedimentary rock
growing parts break off and remains of corals and other calcareous animals and plants accumulate as sediments
Limestone
What 2 phases of buildup contributed to Guam’s geological history
Volcanic and Carbonate
No longer volcanically active
Primality submarine volcanism
Guam, Rota, Tinian, Saipan, FDM
Volcanic Phase