Inner Earth processes and systems - Physical Processes in Earth and Environmental Sciences - page 218

surface

Plutonic
melt

Minimum principal stress trajectories
Maximum principal stress trajectories
and melt intrusion for cone sheets
Ring dykes injected along planes
<90 o to minimum stress trajectories

Fig. 5.24 Stress trajectories and associated intrusions above an
upward-moving body of melt. Cone sheets form when magma
pressure exceeds lithostatic pressure, vice versa for ring dykes.

Fig. 5.26 Vertical basic dyke cutting pillow lavas (just visible
to left). Cyprus.

(a)

t = 1 t = 2 t = 3

m 2

(b) (c)

Fig. 5.25 Magma melts may intrude other melts or solids with variable viscous or elastic properties. (a) Saffman-Taylor viscous fingering results
when a fluid is injected into a more viscous (and immiscible) fluid. The process is illustrated here by a time sequence of injection along a
conduit. Note reduction of finger population and increased elongation with time. (b) Here the fluid is injected from the center outward in
3D - note the radial pattern, finger branching, and fractal-like nature of the process. (c) Here the fluid is injected from the center outward into
an elastic material - note the reduction of branching and the many perpendicular junctions.