Geology Reference
In-Depth Information
(a)
(b)
Figure 2.7.
Synformal structures in granite (a) at Tenaya Lake, Yosemite, Sierra Nevada, California, (b) in the
Joshua Tree National Monument, southern California.
joints and the inferred age of the joints on Dartmoor, England: the former are geologically
youthful whereas the latter are of considerable antiquity, so that it seems at least as reasonable
to suggest that the joints determined the form of the land surface as the converse.
- The examples of fractures developed parallel to young erosional surfaces (e.g.
Fig. 2.6
)
are bet-
ter explained in terms of stress trajectories adjusting to new surface configurations, which are
surfaces of least principal stress.
-Several morphological and structural features developed on and in granitic rocks are incom-
patible with the tensional or expansive conditions implied by offloading. For example, structural
domes, wedges, and overthrusting like that developed and exposed at the Mariz quarries, near
