Geology Reference
In-Depth Information
OVERLYING
FLOW UNIT
A
1
2m
A
A
2
UPPER PART OF FLOW UNIT
A
1
Chilled and fractured flow top
A
2
Spinfex
LOWER PART OF FLOW UNIT
B
1
B
1
Foliated skeletal olivine
B
2
-B
4
Medium-to fine-grained peridotite
B
3
Knobby peridotite
B
2
B
B
3
B
4
UNDERLYING
FLOW UNIT
Figure 8.14
Classic schematic section through a komatiite flow highlighting the
spinifex horizon (zone A) and cumulate horizons (zone B).
8.5 Summary of the Field Characteristics
of Mafic-Ultramafic Intrusions
1. Medium- to coarse-grained gabbro (cpx
>
opx), norite (with opx
<
cpx)
and ultramafic rocks occur as isolated within-plate intrusions, and also as
part of ophiolite sequences that are tectonically emplaced into continental
suture zones.
