Geology Reference
In-Depth Information
(a)
(b)
(c)
1cm
(d)
Figure 4.9
(a-c) Schematic amygdaloidal structure in lava. (a) and (b) Silica
(white) was deposited on the walls of the original vesicles, and subsequently
chlorite (lined) filled the remaining open spaces. The vesicles in which the amyg-
dales of (b) were deposited were flattened and drawn out by the flowing of the
lava. (c) Amygdales and larger cavities with lining and stratified fillings of sil-
ica indicating way-up. (d) Picture of amygdaloidal basalt from core samples,
Namibia.
