This outcrop formation is within the Belt-Purcell
supergroup,
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It is considered that the Belt-Purcell sediments were in a
trough within a continent which rifted off and drifted away
The following is a quote from Don Winston, University of
Montana. "..for the past twenty five years I have concentrated on
stratigraphy and sedimentology of the Middle Proterozoic Belt
Supergroup ... The Belt was deposited in a huge intracratonic basin
that stretched across western Montana , northern Idaho and into
eastern Washington and Canada . It was filled by sand, silt, clay,
and carbonate sediments that locally reach more than 18 km thick.
The sedimentary structures of these rocks are beautifully
preserved, since they were deposited 1.5 to 1.4 billion years ago.
They reveal a world of pure sedimentary processes unfettered by
plants and animals. " They....."reveal a world of gigantic
sheetflood alluvial aprons and shallow seas or lakes, for which
there are no modern counterparts."
These sedimentary rocks are the oldest in S. BC.
The upper levels of this outcrop consist of quartz rich
sandstone interbedded with argillite and were probably deposited in
deep water. A fault movement then thrust this ocean floor on top of
the surface and the shallow water rocks that were much younger.
Thus creating an inverted topography which is an anomaly as the
surface rocks are generally younger than the underlying rocks.
To log this earthcache, please email the owner with the
following:
a) number of people in your group
b) approximate dimensions of this outcrop
c) Approximate height of formation at nearby mine which can be
observed from highway
d) what colours are seen in these rocks
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