Geoscience Reference
In-Depth Information
Figure 9.59.
Sections
across the Chile Trench
and the Andes at 23
◦
S: (a)
topography, vertical
exaggeration 10 : 1; (b)
free-air gravity anomaly;
and (c) density model,
true scale (densities are in
10
3
kg m
−3
). (After Grow
and Bowin (1975).) (d) A
schematic geological
cross section through the
central Andes. Arrows
indicate rising magma.
Most of the new material
being added to the crust
at this destructive plate
boundary is in the form of
huge diorite intrusions.
The andesite volcanics
provide only a small
proportion of the total
volume. The vertical is
exaggeration is 5 : 1.
(From Brown and
Hennessy (1978).)
