ARCHES NATIONAL PARK
(photos from the United States Geological Survey &
the textbook CD)
Balanced Rock with stratigraphy labeled (below).
Delicate Arch and the La Sal Mountains in the distance (= Tertiary intrusive igneous
rocks). Delicate Arch is developed at the contact between the Slick Rock
Member and the Moab Member of the Entrada Sandstone.
Delicate Arch - the cliffs are Slick Rock Member sandstones. Delicate Arch and
the other weathering structures adjacent to it are Moab Member sandstones.
Double Arch - two natural arches that share a pedestal - a very rare
feature. The rocks are Slick Rock Member sandstones (above) and Dewey
Bridge Member interbedded siltstones-sandstones (below). Note the
spheroidal weathering at the top left of Double Arch.
Blind arches developed at the contact between Slick Rock Member sandstones (above)
and Dewey Bridge Member interbedded siltstones-sandstones (below). The
yellowish-brown rocks at the bottom (below the reddish Entrada Sandstone
cliffs) are the upper Navajo Sandstone.
Sandstone fin at Park Avenue. The solid sandstone cliffs are Slick Rock Member
sandstones (Entrada Sandstone). The thin-bedded interval at the bottom
represents interbedded siltstones-sandstones of the Dewey Bridge Member of the
Entrada Sandstone.
Sandstone fins developed in Slick Rock Member sandstones of the
Entrada Sandstone. The fins are separated from each other by
closely-spaced, erosion-widened fractures (joints).
Landscape Arch developed in the Slick Rock Member of the Entrada
Sandstone.
North Window and South Window natural arches developed at the Slick Rock
Member-Dewey Bridge Member contact (Entrada Sandstone). Note the
spheroidal weathering at the cliff tops.
Private Arch in the Devil's Garden area.
Tower Arch at Klondike Bluffs.
Turret Arch