Environmental Engineering Reference
In-Depth Information
FIGURE 6.21
Arid climate landform: horizontally bedded sedimentary rocks (Grand Canyon National Park, Arizona; scale
1:48,000). (Courtesy of USGS.)
The most favorable factor for cavity development and collapse in limestones is the with-
drawal of groundwater by pumping as described in
Section 10.4.2.
6.2.4
Metamorphic Rock
Formations
Metamorphic rocks often extend over very large areas, normally intermixed with igneous
rocks and associated with mountainous and rugged terrain, the irregularity of which
relates to the climate.
The landform results from differential weathering between rocks of varying resistance
and develops most intensely along weakness planes. Drainage patterns depend primarily
on joint and foliation geometric forms: rectangular patterns result from regular forms and
angulate patterns from irregular forms.
Gneiss
Tropical Climate
The Landsat image in
Figure 6.28
covers a portion of the Brazilian crystalline complex in
the state of Rio de Janeiro. Differential weathering has produced numerous parallel
