Mantle

Question 1

Why is the mantle still molten in parts?

Answer 1

1-2% of upper mantle, due to radioactive heat, behaves like plastic

Question 2

What form is the outer mantle?

Answer 2

Solidified and crystallised

Question 3

What happened to volatiles?

Answer 3

Given off to form primitive atmosphere of CO2, H20 and SO4

Question 4

How is the mantle studies?

Answer 4

Ophiolites and Xenoliths or indirectly using seismic activity

Question 5

What mineral dominate?

Answer 5

Olivine and pyroxene and minerals that prefer the metallic phase

Question 6

What is the GMO and how is it former?

Answer 6

Global Magma Ocean, formed due to gravitational potential energy. 700km deep and ultrabasic

Question 7

Where is the upper-lower mantle boundary found?

Answer 7

720km

Question 8

What is the composition of the upper mantle?

Answer 8

> 70% olivine, 20-30% pyroxene, 10% Al

Question 9

What happens to the Al phase at depth?

Answer 9

> 70km = garnet, <70-20km = spinel, <20km = plagioclaise

Question 10

What trace elements can be found in the upper mantle?

Answer 10

Ni @ 500ppm