Schist (Pw et al. 1976). This metamorphic unit
Surficial and bedrock geology
Unconsolidated deposits of the Chena River
is generally of lower greenschist facies, and the
and its smaller tributaries make up most of the
age, although controversial, is thought to be pre-
surficial materials south of Birch Hill (Pw et al.
Jurassic (Pw et al. 1976). Birch Hill, which
1976). These deposits are mainly former point
bounds the northern part of the cantonment, is
bars, swales, channels or sloughs, and related
also composed of this highly fractured and foli-
overbank deposits resulting from alluvial pro-
ated schist. In most areas of Birch Hill, the bed-
cesses. Drilling has revealed that most of the
rock is overlain by eolian silt with thicknesses
surficial deposits on Fort Wainwright consist of
that may exceed 3 m or more. Various processes
gravels and sands, with sporadic silt layers and
have moved weathered bedrock and silt down-
lenses (U.S. Army Engineer District, Alaska, un-
slope off Birch Hill, forming heterogeneous de-
published borehole records). There is a layer of
posits of mixed grain sizes, colluvium, peripheral
silt, usually less than 1 m thick, typically just
to its base.
below a surface layer of organics.
The unconsolidated materials of the Chena
Site descriptions
River floodplain lie unconformably above dark
The OU-3 sites that are under investigation in
pelitic schists of the YukonTanana Complex
the Canol Road area include the Tank Farm, the
(King 1969), formerly identified as the Birch Creek
Truck Fill Stand and the Canol Road pipeline
Figure 4. Aerial photograph mosaic of the region generally north of the Chena River from 9 September 1949. The
approximate area of the Truck Fill Stand is outlined.
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