6_Nickel: Petrological and Geochemical Background

Question 1

In the processes of magma development, what is a magmatic system?

Answer 1

the site of melting, the pathway of magma migration and the site of crystallization within a specific geological and tectonic
environment; may extend from the mantle to the upper crust in most cases.

Question 2

What contributes to the composition of an igneous rock?

Answer 2

1. Site of melt formation in the mantle
2. Melt transport
3. Site of final crystallization

Question 3

Processes controlling magma and igneous rock compositions:

Answer 3

1. Partial melting and interaction with source minerals.
2. Interaction with wall-rocks.
3. Assimilation of wall-rock melts.
4. Mixing of magmas from various sources.
5. Separation into immiscible melts.
6. Fractional crystallization.
7. Mineral accumulation.