Geology Reference
In-Depth Information
Figure 4.13
Schematic cross-sections of domes, showing flow lines (fine lines),
joints (heavy lines) and brecciated margins (stippled). The arrows indicate the
direction of lava movement. (a) Dome built on a nearly horizontal surface.
(b) Dome built on a sloping surface. (c) The top of the dome has sagged due
to drainage of magma back into the vent and to slight spreading of the dome.
(d) Summit of the dome broken by faults due to down-slope movement of the
main mass of the dome. (e) Cross-section of a dome built within a composite
cone, showing steep fan structure developed within a confining wall of crumble
breccia.
