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The Wave is a sandstone rock formation located in the United States of America near the Arizona–Utah border, on the slopes of the Coyote Buttes, in the Paria Canyon-Vermilion Cliffs Wilderness, on the Colorado Plateau. It is famous among hikers and photographers for its colorful, undulating forms, and the rugged, trackless hike required to reach it. There is a lottery for next day permits (ten permits) in person or on line (ten permits) several months before. If you win the agency will supply you with map and information. ==Geology== “The Wave” consists of intersecting U-shaped troughs that have been eroded into Navajo Sandstone of Jurassic age. The two major troughs, which comprise this rock formation, are wide by long and wide by long. Initially, infrequent runoff eroded these troughs along joints within the Navajo Sandstone. After their formation, the drainage basin, which fed rainwater to these troughs, shrank to the point that the runoff became insufficient to contribute to the cutting of these troughs. As a result, the troughs are now almost exclusively eroded by wind, as indicated by the orientation of erosional steps and risers cut into the sandstone along their steep walls. These erosional steps and risers are oriented relative to the predominant direction of the wind as it is now naturally funneled into and through these troughs.〔Loope, D.B. and J.A. Mason (2006) ( ''Landforms generated by wind erosion of Navajo Sandstone outcrops at the Wave (Colorado Plateau, Utah / Arizona border.)'' ) (Geological Society of America Abstracts with Programs. ) vol. 38, no. 7, p. 279.〕〔Loope, D.B., W.M. Seiler, J.A. Mason, and M.A. Chan (2008) (''Wind scour of Navajo Sandstone at the Wave (central Colorado Plateau, U.S.A.)'' ) (''Journal of Geology''. ) vol. 116, pp. 173-183.〕 The Wave exposes large-scale, sets of cross-bedded eolian sandstone composed of rhythmic and cyclic alternating grainflow and windripple laminae. The rhythmic and cyclic alternating laminae represent periodic changes in the prevailing winds during the Jurassic as huge sand dunes migrated across a sandy desert. The thin ridges and ribbing seen within The Wave is the result of the differential erosion of rhythmic and cyclic alternating grainflow and windripple laminae within the Navajo Sandstone. These laminae have differing resistance to erosion as they have been differentially cemented according to variations in the grain size of the sand composing them. The soft sandstone, including the ridges and ribbing, of The Wave is fragile. As a result, persons must walk carefully to avoid breaking the small ridges.〔Seiler, W.M. (2008) (''Jurassic Navajo sandstone of Coyote Buttes, Utah/Arizona : coloration and diagenetic history, preservation of a dinosaur trample surface, and terrestrial analogs to Mars.'' ) Unpublished M.S. thesis, Dept. of Geology and Geophysics, University of Utah, Salt Lake City, Utah.〕〔Chan, M.A., and A.W. Archer (2000) (''Cyclic eolian stratification on the Jurassic Navajo Sandstone, Zion National Park: Periodicities and implications for paleoclimate.'' ) in D.A. Sprinkel, T.C. Chidsey, Jr., and P.B. Anderson, eds., pp. 607-618. (''Geology of Utah's Parks and Monuments.'' ) Utah Geological Association, Salt Lake City, Utah.〕〔Caputo, M.V. (2003) ''Geology of the Paria Canyon-Vermilion Cliffs Wilderness, Utah and Arizona.'' in D.A. Sprinkel, T.C. Chidsey Jr., and P.B. Anderson, eds., (''Geology of Utah's Parks and Monuments.'' ) Utah Geological Association, Salt Lake City, Utah.〕 In places, The Wave exposes deformed laminae within the Navajo Sandstone. These laminae were deformed prior to the lithification of the sand to form sandstone. Judging from their physical characteristics, this deformation likely represents the trampling and churning of these sands by dinosaurs after their deposition. Dinosaur tracks and the fossil burrows of desert-dwelling arthropods, such as beetles and other insects, have been found within the Navajo Sandstone within the North Coyote Buttes Wilderness Area.〔〔Milan, J., D.B. Loope, and R.G. Bromley (2008) ( ''Crouching theropod and Navahopus sauropodomorph tracks from the Early Jurassic Navajo Sandstone of USA.'' ) Acta palaeontologica Polonica. vol. 53, no. 2, pp. 197-205.〕〔Ekdale, A.A., R.G. Bromley, and D.B. Loope (2007) ''Ichnofacies of an ancient erg: a climatically influenced trace fossil association in the Jurassic Navajo Sandstone, Southern Utah, USA.'' in W. Miller, ed. , 562–576, ''Trace Fossils. Concepts, Problems, Prospects. '' Elsevier, Amsterdam.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「The Wave, Arizona」の詳細全文を読む スポンサード リンク
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