ZION NATIONAL PARK
(photos from the United States Geological Survey)
Zion Canyon (looking ~east) - the reddish-brown cliffs are quartz sandstones of
the Navajo Sandstone (Lower Jurassic). The vegetated slopes below
that are weathered shales-siltstones-sandstones of the Kayenta Formation
(Lower Jurassic).
Zion Canyon (looking east) - the reddish-brown cliffs are quartz sandstones of the
Navajo Sandstone (Lower Jurassic). The vegetated slopes below that
are weathered shales-siltstones-sandstones of the Kayenta Formation
(Lower Jurassic).
ZION NATIONAL PARK
(photos from the textbook CD)
Pine Creek Canyon (above & below; looking ~west), an east-west
trending tributary valley of Zion Canyon (in the distance). The
reddish-brownish vertical cliffs are Navajo Sandstone (~Upper Triassic to
~Lower Jurassic) (see labeled photo below). The slopes below that are
weathered shales-siltstones-sandstones of the Kayenta Formation.
ZION NATIONAL PARK
(photos by James St. John)
Zion Canyon (looking east) - the reddish-brown and whitish cliffs are Navajo
Sandstone (Lower Jurassic). The vegetated slopes below that are
weathered shales-siltstones-sandstones of the Kayenta Formation (Lower
Jurassic).
Zion Canyon (looking ~east) - the orangish-brown cliffs are Navajo Sandstone
(Lower Jurassic). The vegetated slopes below that are weathered
shales-siltstones-sandstones of the Kayenta Formation (Lower Jurassic).
Navajo Sandstone (looking ~northeast) - well-defined cross bedding in
quartz sandstone cliffs of the Navajo Sandstone (Lower Jurassic), northern wall
of Pine Creek Canyon, a tributary valley to Zion Canyon. The dark
reddish-brown and blackish surfaces are desert varnish, consisting of a
surficial coating of hematite (= reddish brown) and pyrolusite (manganese
dioxide, MnO2; = blackish).
Navajo Sandstone (looking ~south-southwest) - well-defined cross
bedding in quartz sandstones of the Navajo Sandstone (Lower Jurassic) at
Checkerboard Mesa (see below).
Checkerboard Mesa (above & below; looking ~south-southwest) -
cross-bedded quartz sandstones of the Navajo Sandstone (Lower Jurassic).
The origin of the vertical to subvertical grooves is not certain, but they
appear to be surficial, stress-related expansion/contraction cracks that have
been later enlarged as water runoff channels.
Great Arch (looking ~north-northeast) - a blind arch developed at the base of the
Navajo Sandstone cliff near the eastern end of Pine Creek Canyon (a tributary
valley to Zion Canyon). Blind arches in this area form by bottom-up
weathering and erosion as a result of springs emerging at the Navajo Sandstone-Kayenta
Formation contact (= base of the sandstone cliffs & top of the shale-rich
slopes).
North Fork of the Virgin River (looking ~south-southwest) - this small modern river
is responsible for ~3000' worth of downcutting and dissection at Zion Canyon.