Page 275 - Microtectonics

268 10 · Special Techniques
Fig. 10.4a,b.
Secondary electron images of a
series of fracture surfaces (see
text) of a slate sample observed
by SEM. Details of the structure
can be seen, but grey tones can-
not be used to distinguish min-
eral composition because of the
rough surface. a Bedding parallel
foliation is folded and fold limbs
define a first slaty cleavage S 1 .
b Spaced slaty cleavage S . Micro-
1
lithons contain micas that are
truncated against micas in the
cleavage lamellae. This slaty
cleavage formed at slightly higher
metamorphic grade than a. Mas-
sive grains in microlithons prob-
ably consist of quartz. Rheini-
sches Schiefergebirge, Germany.
Width of view a 20 µm; b 95 µm.
(Photographs courtesy K. Weber
1981)