Orocline
From Wikipedia, the free encyclopedia
An orocline — from the Greek words for "mountain" and "to bend" — is a bend or curvature of an orogeneic (mountain building) belt imposed after it was formed.[1] The term was introduced by S. Warren Carey in 1955 in a paper setting forth how complex shapes of various orogenic belts could be explained by actual bending, and that understanding this provided "the key to understanding the evolution of the continents".[2] Carey showed that in a dozen cases where such bends were undone the results were substantially identical with continental reconstructions deduced by other means.[3] Recognition of oroclinal bending provided strong support to the subsequent theory of plate tectonics.
Contents
List of oroclines[edit]
- The Bolivian Orocline is a seaward concave bending in the coast of South America and the Andes mountains at about 18° S.[4][5] At this point the orientation of the Andes turns from Northwest in Peru to South in Chile and Argentina.[5] The Andean segment north and south of the orocline have been rotated 15° to 20° counter clockwise and clockwise respectively.[5][6] The orocline area overlaps with the area of maximum width of the Altiplano Plateau according to Isacks (1988) the orocline is related to crustal shortening.[4] The specific point at 18° S where the coastline bends is known as the Arica Elbow.[7]
- The Maipo Orocline or Maipo Transition Zone is an orocline located between 30° S and 38°S in the Andes with a break in trend at 33° S.[8]
Notes[edit]
- ^ Carey 1955, p. 257. Note that the initial formation does not have to be straight.
- ^ Carey 1955, p. 257.
- ^ Carey 1955, p. 255.
- ^ a b Isacks, Bryan L. (1988), "Uplift of the Central Andean Plateau and Bending of the Bolivian Orocline" (PDF), Journal of Geophysical Research 93 (B4): 3211–3231
- ^ a b c Kley, J. (1999), "Geologic and geometric constraints on a kinematic model of the Bolivian orocline", Journal of South American Earth Sciences 12 (2): 221–235
- ^ Beck, Myrl E. (1987), "Tectonic rotations on the leading edge of South America: The Bolivian orocline revisited", Geology 15 (9): 806–808
- ^ Prezzi, Claudia B.; Vilas, Juan F. (1998). "New evidence of clockwise vertical axis rotations south of the Arica elbow (Argentine Puna)". Tectonophysics 292: 85–100.
- ^ Arriagada, César; Ferrando, Rodolfo; Córdova, Loreto; Morata, Diego; Roperch, Pierrick (2013), "The Maipo Orocline: A first scale structural feature in the Miocene to Recent geodynamic evolution in the central Chilean Andes" (PDF), Andean Geology 40 (3): 419–437
References[edit]
- Carey, S. Warren (1955), "The Orocline Concept in Geotectonics, Part I" (PDF), Papers and Proceedings of the Royal Society of Tasmania 89: 255–288.
See also[edit]
- Van der Voo, Rob (December 2004), "Paleomagnetism, Oroclines, and Growth of the Continental Crust" (PDF), GSA Today 14 (12): 4–9, doi:10.1130/1052-5173(2004)014<4:POAGOT>2.0.CO;2.
