Final Exam Geography 100
Terms
undefined, object
copy deck
- landforms
-
continental landforms are the result of internal and external processes.
Internal Process: works from within the earth
- Internal Process
-
works from within the earth
produces initial landforms
powered by earths internal energy - Igneous rock
- formed from the cooling of magma
- sedimentary rock
- formed from the accumlation of sediment
- metamorphic rock
- formed when other two types change due to significant heat or pressure
- core
- spherical central mass of the earth composed largely of iron consisis of an outer liquid zone and inner solid zone
- mantal
- rock layer of earth beneath the crust and surrounding the core, composed of ultramaficigneous rock of silicate minerals
- crust
- outer most solid layer of the earth. composed layer
- lithospere
- rigid outer shell of earth, includes crust and upper part of mantle
- asthenosphere
- plastic layer beneath the lithosphere
- Plate Boundaries
-
spreading boundaries
on continental plates or ocean basins
converging boundaries(two types)
subduction
uplift
transform boundary
sideways motion relative to one another - spreading boundaries
-
plates move apart from one another
crust uplifts and stretched
magma rises to form new rock new crust created
can happen with continental plates
can happen in ocean basins-basin widens and new crust is formed - Converging boundary-subduction
-
plates undergoing subduction are associated with active continental margins
oceanic plate collides with continental plate
oceanic plate more dense gets subducted
sediments accumlate in deep trench
deep ocean sediments
terrestrial sediments
deformed scraped off subducting plate
wedge forms at the plate boundary
sediments transformed into metamorphic rock
subduction descent of the edge of a lithospheric plate under an adjoining plate and into the asthenosphere - orogens and collisions
-
Contiental suture: long narrow zone of crustal deformation produced by a continental collision
continental lithospheric plates coverage
boy buoyants neither subducts - orogeny
- major episode of tectonic activity resulting in strata being deformed by folding and faulting
- Nappe
- overturned recumbent fold of strata, usually associated with thrust sheets in a collision orogen
- transforms boundary between plates
-
plates move past each other
transforms boundary
transforms faults - passive continental margins
- no strong tectonic activity within 50 million years
- active continental margin
- deep off shore trenches volcanic activity
- The power source for plate movements
-
radiogenic heat: heat generated by the decay of radioactive isotopes
heat generated by decay of isotopes of uranium, thorium, and potassium
independent of surface conditions
heat keeps rock below crust close to melting point
radiogenic heat power source for plate motions
exact mechanism unknown
possibly convection currents in mantle
possibly gravity - relief features of the continents
-
Active mountain-making regions
mountains result from volcanism or tectonic activity
active mountain making belts from alphine
chains: narrow zones along the margins of lithospheric plates - continental crust includes
-
active mountain making belts
regions of stable older rock
continental shields: very old low tying igneous and metamorphic rock
mountain roots: remains of older mountain belts, long, narrow ridges - relief features of oceanic basins
-
oceanic crust < 60 million years old
continental crust > 1 billion years old
ocean basins have: midoceanic ridge axial rift - subduction zone
- convergant plate boundary
- midocean ridge
-
divergant plate boundary
overtime "terranes" may accrete along the coastline forming a complex patter of different rocks and landscape features
PNW is made up of lots of different rocks from many sources - landforms made up Ice sheets
-
ice sheets pick up rock fragments, transport them, and deposity them when the ice evaporates or melts
glacial drift: general term for all varieties and forms of rock debris deposited by ice sheets
stratified drift: layers of sorted clays, silts, sands, or gravels, deposited by meltwater streams or lakes
till: unstratified mixture of rock fragments of all sizes, deposited directly by the ice
ground moraine: thin, ven cover of till
moraine: accumulation of rock debris carried by an ice sheet and deposited by ice to become a depositional landform
outwash plain: formed from stratified drift left by streams issuing from the ice