Geology Reference
In-Depth Information
◗
Figure 14.7
Response of a Hypothetical Glacier to Changes in Its Budget
Snowfall
Firn limit
Summer snow and
ice melt (A)
Winter accumulation
of snow and ice (B)
Terminal moraine
A = B; GLACIER
TERMINUS
STATIONARY
Glacial terminus
a
Winter accumulation (B) and summer snow and ice melt (A) are equal. That is, additions and losses are equal
so the glacier's terminus remains stationary. The terminal moraine is deposited at the terminus of a glacier.
Snowfall
Firn limit
(A)
(B)
Recessional moraine
Terminal moraine
A is much greater
than B; TERMINUS
RETREATS
b
Summer snow and ice melt (A) are much greater than winter accumulation (B), and the glacier's
terminus retreats, although the glacier continues to move by plastic fl ow and basal slip. The recessional
moraine is deposited at the glacier's new terminus.
Firn limit
(B)
B is much greater
then A; TERMINUS
ADVANCES
(A)
Crushed
forest
Flattened
older moraines
c
Winter accumulation (B) is much greater than summer snow and ice melt (A), so the glacier's
terminus advances. As it does so, it overrides and modifi es its previously deposited moraines.
Search WWH ::
Custom Search