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L2 Natural Bridge. Natural Bridges National Monument, Utah, USA
Position:
N37° 35'
W110° approx.
Elevation:
6000' / 1825m
Image format:
MF 35mm
NATURAL BRIDGES
These are rare features though many are concentrated in the red
rock country of southern Utah, USA. Within the Natural Bridges
National Monument boundary there are several bridges. The Paiute
Indians called them by the collective name "Ma-Vah-Talk-Tump"
meaning "under the horses belly"! Each of the larger bridges was
given a Hopi Indian name when President Howard Taft enlarged the
boundaries of the park in 1909. This bridge is called "Owachoma".
Owachoma has the following dimensions:
Height 106' / 32m
Span 180' / 55m
Width 27' / 8m
Minimum thickness 9' / 3m
Natural Bridges are formed by river erosion and modified by weathering
processes. The processes apply all over the world but it takes
a special type of rock to form a natural bridge and such rock
types, strong thick beds of sandstone, are common in Utah, USA.
Imagine a river flowing around a bend or MEANDER. The water tends
to flow fastest on the outside of the bend and ERODES the river
bank. What if the river was meandering through a canyon? During
times of flood, the river will erode the canyon walls on the outside
of the bends and may even break thorough the MEANDER CORE, by-passing
the main meander loop. If the rock is strong like this sandstone
in the picture and bridge may be formed and may remain until it
eventually collapses. Don't miss the Rainbow Bridge image at L76 and the great sketches and diagrams at www.desertusa.com/gc/rainbow/rainbow.html .
Contrast the formation of natural bridges (primarily by EROSION)
and the evolution of natural Arches by WEATHERING.
Less detail
Image Trail:
L37 L38 L39 (Incised Meanders) L76 (Rainbow Bridge) & L58 - L62 (Natural Arches)
L37 Incised meanders. Goosenecks, San Juan River. Utah
L38 Incised meanders. Goosenecks, San Juan River. Utah
L39 Incised meanders. Goosenecks, San Juan River. Utah
L76 The Rainbow Bridge, Lake Powell, Utah, USA
L58 Rock Fins (I). Arches National Park. Utah, USA
L59 Rock Fin (II). Arches National Park. Utah, USA
L60 Landscape Arch. Arches National Park. Utah, USA
L61 An evolving Arch. Arches National Park. Utah, USA
L62 The End & the Beginning of Arches. Arches Ntnl Park.
Links:
http://geography.com.sg/rivers/index.html
www.ccsi.com/~jwilbur/nabs/gallery.htm
www.desertusa.com/gc/rainbow/rainbow.html |
