Lecture 2 Flashcards
(122 cards)
Permafrost
soil and sedimentation that have remained frozen for two or more consequtive years
active layer of soil( in terms of permafrost)
is the seasonally frozen ground on top of subsurface permafrost-thaws every summer
in winter the active layer freezes, trapping plant and animal material before it can decompose completley
-creates carbon rich soils
carbon in permafrost is ___ the ammount stored in the atmosphere
twice
endogenic system
exogenic
consists of proccesses operating in earths interior driven by heat and radioactive decay
processes operating at earths surface driven by solar energy and movement of air, water, and ice
eons
eras
periods
epochs
largest time span
Shortst
EpochHolocene
Eon: phanerozoic
the current era is the _______
cenozoic(quaternary period)
Earths core is a / of earths mass and a / of its volume
1/3, 1/6
inner and outer core are seperated by th ______ zone
inner core is solid ____
outer core is _____
Outer core is seperated from mantle by a transition zone seveeral hundred km wide at a depth of ____
lower and upper mantle represent __% of earths volume
transition
iron(remains solid despite heat because of pressure)
molten, metalic iron with lighter density
2900km
80
________ discontinuity occurs at a depth of about 2900k between outer core and lower mantle
________ discontinuity occurs between uppermost mantle and crust
Glutenburg
Mohorovicic(moho)
-seismic waves change at this depth due to sharp contrasts in material composition and density
7 segments of earths depth(deepest to shallowest)
Inner core Outer Core Lower Mantle Upper Mantle Asthenosphere Uppermost Mantle Continetal Crust
crustal thickness is thickest beneath ______ at 50-60km
30 km thickness beneath _______
5km thickness beneath _______
mountain
continental
oceanic
______ and _____ make up __% makes up earths crust
Oxygen and silicon
74%
-more oxygen in crust than atmosphere
continental crust is ___ in density in comparison to oceanic= 2.7 vs. 3.0
Continental composed of ______
oceanic composed of _______
lower
Granite
Basalt
Lithosphere vs Asthenosphere
- Rigid Layer
- crust and uppermost mantle to about 70 km
- plastic layer
- within mantle from 70km to 250km
- convection currents in this zone in part causes the shifting of lithospheric plates
Are crust and lithosphere the same?
No, the crust makes up the upper portion of the lithosphere
isostasy
the balance between the buoyancy and gravitational forces
-explains elevations of continents and the depths of ocean floors as determined by vertical movements of earths crust
isostatic rebound
if the load is removed, such as when a glacier melts, the crust rides higher and the astenosphere flows back toward the region of uplifting lithosphere
Earths fluid outer core generates most of earths ______ field
magnetic
-circulation in the outer core converts thermal and gravitational energy into magnetic energy
95% o earths crust is made up of ______
silicates
Igneous Rock
one that solidifies and crystallizes from a molten state
- makes up approximately 90% of earths crust
- coarse if beneath the surface like granite
- finer grained from fast cooling at surface is basalt
Pluton
.intrusive igneous rock that cools slowly in the crust forms…
-largest plutonic form is Batholith
Sedimentary Rock
-4 types
.Driven by solar energy and gravity
1.Clastic:Weathering, Deposition, Lithification
- Biochemical:dissolved minerals build up to form rocks
- ex:limestone - Organic:
- Chemical:dissolved minerals build up to form rocks
CAN BEES OPEN CANS?
Lithification
occurs as loose sediment is hardened into solid rock
Metamorphic
.any igneous or sedimentary rocks can be transformed into metamorphic by going through physical and chemical changes under pressure and increased temp
caused by: heating, pressure, heating and pressure together, and compression and shear