Campbell Creek.
glacier may be alternately active and inac-
cle
tive over a period of years. Some vegeta-
Landslide deposits resulting from earth-
tion covers surface. Generally more stable
flows (Holocene and late Pleistocene)--
Similar to other landslide deposits within
than active rock glaciers, but some insta-
the mountains, but interpreted on the
bility likely, especially if excavated,
basis of landform to have been emplaced
because of loose nature of material and
in a probably more fluid state and there-
likelihood that some interstitial ice may be
fore may include a higher proportion of
present and that some massive clear ice
finer-grained material. Contacts generally
may be present at depth. Occur in south-
well defined. Mainly in long, narrow
eastern part of map area down-valley from
occurrences in gullies and small valleys
rock glaciers, and in some nearby valleys
within Chugach Mountains.
that no longer contain active rock glaciers
at their heads.
Rock glaciers and rock-glacier deposits
rds
Deposits of valley-side source (Holo-
Rock glaciers may be regarded as transitional
cene)--Similar to other rock-glacier depos-
between true glaciers and a kind of active, slow-
its but appear to have headed in and
moving landslide, and their deposits are likewise
derived from colluvial deposits along the
transitional between ground-moraine and collu-
side of long, narrow valleys. Probably do
vial deposits.
not have, and may never have had, clear-
ice cores of any significant thickness.
rg
Appear to have originated as coalesced
Active rock glaciers (latest Holocene)--
Accumulations of mainly angular to some
lobate rock glaciers. Occur prominently as
subrounded rock fragments still actively
major valley fills in Snowhawk and North
being transported, derived from upslope
Fork Campbell Creek Valleys.
talus deposits or directly from bedrock.
rdo
Older rock-glacier deposits (Holocene
Contain ice-rich matrix and move very
and late Pleistocene)--Similar to younger
slowly downslope. Surface generally lacks
rock-glacier deposits but with somewhat
vegetation, dominated by cobble- and
more subdued surface that is more com-
boulder-size fragments. At depth, sub-
pletely covered by low vegetation. Surface
stantially more fine-grained material may
somewhat resembles that of ground mor-
be present to form coarse, rubbly, massive,
aine, but is more finely hummocky rather
and poorly sorted diamicton; at greater
than smooth, reflecting presence of angu-
lar to subangular cobble- and boulder-size
depth, dominantly clear glacier ice may be
fragments just beneath vegetation cover.
present, as reported in some rock glaciers
Not moving as an active rock glacier and
(Moore and Friedman 1991). Thickness
unlikely to contain glacier ice, although
several to a few tens of meters. Contacts
permafrost likely to be present locally.
generally well defined except gradational
Occur in several small valleys in south-
to talus at upslope margin. Surface moder-
eastern part of map area, commonly in val-
ately hummocky and rough; slopes gener-
leys at altitudes lower than the valleys
ally moderate but steep to very steep
containing younger rock-glacier deposits
along Front and some side margins.
or active rock glaciers.
Unstable because of continuing very slow
movement and potential for melting of
Anthropogenic deposits (latest Holocene)
ice-rich matrix. Occur mainly at heads of
f
Engineered fill--Chiefly compacted peb-
valleys near Tikishla and Temptation
ble gravel, in many places underlain by
Peaks in southeastern part of map area.
more poorly sorted sandy to silty gravel,
rd
Rock-glacier deposits (late Holocene)--
both emplaced to engineering specifica-
Similar to material of active rock glaciers,
tions. Includes some areas where a more
but may contain less interstitial ice or less
heterogeneous assemblage of material
(perhaps no) clear ice at depth. Movement
may have been emplaced without utilizing
probably has ceased and these deposits are
engineering specifications; in a few places
sometimes termed inactive rock glaciers;
includes land areas extensively modified
however, distinction between the two
by earth-moving or rock-quarrying equip-
forms may be difficult to make, or a rock
to contents
Previous Page
