Geoscience Reference
In-Depth Information
Fig. 11.6
Selected areas of
patterned ground from the
Beacon Valley digital
elevation model for three drift
sheets on the valley fl oor
showing the increasingly
diffuse expression of
high-center, sand-wedge
polygons with time in Beacon
Valley: (
a
) Regular
pentagonal and hexagonal
polygons on Taylor II drift in
lower Beacon Valley (from
oblique aerial photo); (
b
)
poorly expressed polygons on
Taylor III drift in lower
Beacon Valley; and (
c
)
diffuse polygons on Taylor
IV drift in central Beacon
Valley. The apparent
lineations on Taylor III and
IV surfaces may refl ect
prevailing wind ablation from
the southwest to northeast
(Bockheim et al.
2009
)
