by encroaching estuarine water as ice
Parkway interchange that was exposed
melted and ice front receded. Extend in a
along Glenn Highway during construc-
relatively narrow belt from North Fork
tion.
Campbell Creek to south edge of map area
ws
Winchester Street deposits--Chiefly medi-
wsu um to fine sand with some interbedded
at an altitude between about 110 and 140
silt. Thickness probably a few to several
m, just downslope from Birch Road depos-
meters. May represent marginal facies of
its. aru are deposits modified by urbaniza-
estuary that had less contact with glacier
tion.
ice than older and higher-level estuaries
represented by Muldoon Road and Abbott
Alluvial deposits
Road deposits. Occur mainly between
These are subdivided into deposits formed by
Chester Creek and North Fork Little
streams 1) along their normal courses and found
Campbell Creek near west edge of map
at or near stream level, as well as in terraces well
area. wsu are deposits modified by urban-
above stream level, and 2) in alluvial fans at one
ization.
or more levels.
wsc Coarse-grained deposits--Dominantly
Alluvium along streams. These deposits are
wscu sand and gravel. A few terrace-like occur-
chiefly gravel and sand formed in present-day
rences mainly adjacent to hills of Muldoon
streams, ancestral streams, and some older
Road and Russian Jack deposits. wscu are
streams no longer present that lack any direct
deposits modified by urbanization.
association with glaciers; they include some fine-
wsp Deposits with peat at surface--May
grained deposits. Generally, they are well bedded
wspu include finer-grained material than else-
and sorted, with clasts commonly rounded to
where within these deposits. Peat com-
well rounded. Thickness is variable, probably a
monly more than 1 m thick. Bootlegger
few to several meters; it may be 10 m or more in
Cove Formation may be present at shallow
large valleys and in large alluvial fans. Contacts
depth. wspu is peat removed during
are well defined. Topography is smooth, with
urbanization; permafrost subsequently
slopes being nearly flat to very gentle, and
reported.
steeper on alluvial-fan deposits. Steep scarps 1 m
mr
Muldoon Road deposits--Chiefly fine sand
to several meters high separate deposits at differ-
mru and silt; locally include interbedded diam-
ent levels between adjacent map units and locally
icton or may consist mainly of crudely
within map units.
bedded fine-sandy diamicton. Thickness
probably several meters. Interpreted as re-
aa
Alluvium in active floodplains (latest
working of ground moraine as inlet water
Holocene)--Gravel and sand transported
encroached upon areas abandoned by gla-
intermittently and deposited temporarily
cier ice. Widespread between Ship Creek
in bars that commonly change their posi-
and South Fork Little Campbell Creek,
tion along braided and single channels.
commonly lower than about 110 m in alti-
Vegetation cover generally absent or just
tude in lower terrain surrounding hills of
beginning to develop in areas that have
Russian Jack deposits into which they may
not been affected directly by the stream for
grade or onto which they may lap. mru are
a few years. Area subject to continuing
deposits modified by urbanization.
erosion and flooding; in places stream
ar
Abbott Road deposits--Chiefly diamicton,
may encroach upon areas adjacent to area
aru
crudely bedded to massive, with some
of map unit. Mapped mainly along Eagle
interbedded silt and fine sand; coarser
River and locally along Ship Creek.
sand and gravel may be present locally. In
al
Alluvial deposits along modern streams
belt about 1 to 2 km wide along Abbott
and in lowest terraces (Holocene)--Chiefly
alu
Road, contain high proportion of rubble in
gravel and sand except in the Eagle River
near-surface exposures, possibly the result
Valley up-valley from South Fork conflu-
of a landslide emplaced either on glacier
ence where sand is more common and
ice or directly in estuarine water shortly
overlies lacustrine silt and clay at depths
after ice withdrew. Thickness several to
of about 7 m. Generally less than a few
about 10 m. Alternately may represent
meters above stream level. Include some
ground moraine only somewhat modified
material of active floodplains still partly in
transport mode in areas too small to map
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