Figure 18
A broader view of West Profile #2 at 34RM507. Note
the small gully filled with dark sediment at the top right of the profile,
underneath the people screening; the slip-off slope leading down to the left;
and the deep creek channel at left, also filled with dark sediment. The latter
is actually two sequential channel cut-and-fills, one atop (and dissecting) the
other. The fill in the gully and the two creek channels is organic enriched soil
containing a jumble of rocks and artifacts. These fills appear to have been
stripped off upslope and/or upstream and redeposited in individual catastrophic
events, presumably as a result of torrential rainfall. The soil in the gully
radiocarbon dates to AD 420. The fill in the lower creek channel dates AD 785,
and that in the upper channel dates AD 1035. These are not the dates of the
erosional events, but the age of the material that was washed into them. Again,
the massive structure, uniform character, and chaotic orientation of the
artifacts and rocks contained within these fills make it clear that they were
indeed washed in all at once, and not formed in place. The three erosional
events thus date some time before AD 420, 785 and 1035. The first date falls
within the Herring Creek pluvial (AD 400-600), and the last two near the
boundaries of the Higgins Creek pluvial (AD 775-1000). We may be seeing the
results of torrential rainfall events at or near the ends of these two pluvials,
stripping off and redepositing soils formed during each. The slip-off slope
indicates a longer term and larger scale canyon incision event, possibly during
the AD 100-400 Herring Creek interpluvial.