Chapter 1. Earth Materials And Geosphere Flashcards
Low velocity zone
250km
Transition zone
410 km
Another transition zone
660km
Crust distance
5-80km
Mantle distance
2885 km
Core distance (rad)
3480 km
Crust by %vol
Less than 1
Mantle %by vol
83%
Core %vol
16%
Lithospheric distance
100km
Asthenospheric distance with transition zone
400-660km
Crust is separated from mantle by _discontinuity
Moho
Oceanic crust thickness
5-7 km
Idealized strat of Oceanic crust composed of _ main layers
3
Layer 1
Sediments
Layer 2
Basalts and dikes
Layer 3
Gabbro and Oceanic crust
Layer 4
Mantle PERIDOTITE
Oldest Oceanic crust age
<180 ma
Location of oldest Oceanic crust
Along w and e borders of N Atlantic Ocean and w pacific
Oceanic crust density
2.9 to 3.1
Ave density of cont crust
2.6 to 2.9
Greenstone belts age
4.28 GA
Composition of earth’s mantle
Ultrabasic ecglogite
Upper mantle comp
Peridotite
Lvz distance
100 to 250 km
Distance top of lvz marks the contact between lithosphere and asthenosphere
100km
Discontinuity at inner to outer core at 5150 km
Lehman
Density of inner core
13
Plates are separated by plate boundary segments that end in?
Triple junctions
Movement of plates
3 types, 2 hybrid(div, con, trans, - ditrans, contrans
Creation of red sea (Arabian separated from African)
5ma
Creation of Indian Ocean
115 ma
Creation of Atlantic ocean
180 ma
Earths largest mountain range (20%of earths surface)
Ocean ridge system
6-18cm per yr warmer and faster
E. Pacific rise
2-4cm/yr spreading rate
Mid Atlantic
Idea sites for epiclastic(detrital) of subd zones
Trench arc systems
Marks path of subd zone
Wadatti benioff zone
3 largest magnitude of equake
1909 Chile Alaska 1964 Sumatra 2004 which produced banda aceh tsunami
Age of himalayan mountain range
40ma
Tule of strike slip with horizontal motion
Trans
Curvilinear zones of intensity faulted or fractured Oceanic crust nearly perpen to ridge axis
Fracture zones
Below lvz, seismic velo is (low, high)
High
Location of transition zone (410-660)
Between upper and lower mantle
Olivine (@14Gpa) transforms into beta spinel or wadsleyite and at high pressure transforms into ringwoodite. T or f
T
(@660km,24gpa) ringwoodite plus garnet to pervoskite and periclase(oxide). T or f
T
Periclase and magnesiowustite are polymorphs ((MG. Fe) o). T or f
T
Lower mantle major minerals
Perovs, periclase, magnesiowustite, stishiovite, ilmenite, ferrite
Above core mantle boundary (130-340km)
D”layer
Core composition
85% Fe 5% Ni 8-10% O S H
Low velo of P wave @2900 km or core mantle boundary
Guttenberg discontinuity
Core mantle boundary density
10-12g/cm3