Weeek 7

Question 1

thickness crust

Answer 1

6-7 km

Question 2

thickness lithosphere

Answer 2

up to 100 km

Question 3

melting starts at

Answer 3

50 km

Question 4

extraction at mid ocean ridges

Answer 4

Melt runs into low-permeability barrier (lithosphere) → Melt is focused due to pressure gradients from flow.

Question 5

ocean layer 1

Answer 5

sediments
0 to 0.5 km
Vp 1.7-2 km/ s

Question 6

ocean layer 2a

Answer 6

Pillow basalt
0.5 km
2-5.5 km/ s

Question 7

layer 2b

Answer 7

sheeted dyke basalt
1.5 km
6-76 km(s

Question 8

layer 3a

Answer 8

Gabbro isotropic
5km
7 km/s

Question 9

layer 3b

Answer 9

gabbro layered

same as 3a

Question 10

layer 4a

Answer 10

Peridotite
Dunite, layered peridotitw
1.2 km
8 km/ s

Question 11

layer 4b

Answer 11

isotropic peridotite

same as 4a

Question 12

geophysical moho

Answer 12

betweeen layer 3b and 4a

so between gabbro and peridotite

Question 13

petrological moho

Answer 13

between layer 4a and 4b so peridotite layers

Question 14

Wadati Berioff Zone

Answer 14

earthquke line, deepest part
dipping planar (flat) zone of earthquakes that is produced by the interaction of a downgoing oceanic crustal plate with a continental plate.

Question 15

when change in temp, depth is sqr root of age

Answer 15

this is not linear bcs as crust gets older it gets colder an denser so submerges

Question 16

Viscosity definition

Answer 16

measure of the resistance of a material to flow or to deform permanently

Question 17

high viscosity means

Answer 17

high resistance to flow, will flow slow (syrup)

Question 18

low viscosity means

Answer 18

low resistance to flow, will flow fast ( water(

Question 19

viscosity n

Answer 19

n as greek letter eta for viscisuty

Question 20

viscosity depends on

Answer 20

mineralogy, composition, water, grain size, strain rate, T and P

Question 21

as temperature increases, n

Answer 21

decreases

Question 22

as preessure increses, n

Answer 22

increases

Question 23

n unit

Answer 23

in pascal per seconds

Question 24

What is a plate?

Answer 24

radi number is smaller than critical radius
cools via conduction
has earthquakes, deforms via brittle deformation ( so breaks not flows)

Question 25

geological boundary

brittle ductile transition

Answer 25

point where viscous and brittle strength meet or interchange

also where lithisphere ends

Question 26

lithosphere ends

Answer 26

brittle ductile transition of a . plate

Question 27

strentgh envelope

Answer 27

dreieck under brittle strength line and above viscous strentgh line