I think 1991 it was the fall of soviet union
Explanation:
This is not pole reversal. Pole reversal does not control how a rocks are formed, they only align the orientation of magnetic minerals in a cooling rock.
Pole reversals occur when the direction of the magnetic north and south changes.
- The rock type with the quartz band oriented perpendicularly from one another must have been formed along a fracture in the rock formation.
- Fractures structurally controls how intrusions are formed.
- The quartz band must have been a fluid from a magmatic body that crystallizes at the late stage with some other minerals.
- Fractures acts as weakness planes in rocks and they are utilized by intrusive bodies to cool.
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Sedimentary rocks brainly.com/question/9131992
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