Geology Reference
In-Depth Information
Figure 4.16
Photo of pillow lavas, Iceland.
way up
(a)
(b)
Figure 4.17
Diagrammatic cross-section showing the distinction between pillow
lava (a) and lobes of pahoehoe lava (b). In (a) the short dashed lines represent
the inner margin of the glassy skin on the pillows, the long dashed lines represent
radial cooling joints and the stippled areas represent sedimentary material filling
interstices between the pillows. In (b) the dotted lines reflect concentric varia-
tions resulting from cooling of the lava lobes. In (a) and (b) the black ornament
represents spaces which would be open in young lavas, but would be filled with
secondary material in older lavas.
