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Detailed Reference Information |
Kiyokawa, S., Taira, A., Byrne, T., Bowring, S. and Sano, Y. (2002). Structural evolution of the middle Archean coastal Pilbara terrane, Western Australia. Tectonics 21: doi: 10.1029/2001TC001296. issn: 0278-7407. |
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The middle Archean coastal Pilbara terrane is composed of two lithotectonic units: the Karratha and Cleaverville-Roebourne supercomplexes. The Karratha supercomplex lies tectonically beneath the Cleaverville-Roebourne supercomplex and consists of 3270 ~ 3250 Ma granitic batholiths and metamorphosed terrigenous sediments. It is identified as a juvenile continental crust with tonalite-trondhjemite-granodiorite type granites. The Cleaverville-Roebourne supercomplex is interpreted as a dismembered immature island arc which has a restored crustal thickness of ~20 km. This supercomplex consists of 3195 Ma bimodal volcanic-chemical sedimentary sequences, metabasite, low-K granitic gneiss and peridotite. Regionally distributed granite-porphyries (circa 3020 ~ 3000 Ma) have intruded all of the coastal Pilbara terrane. Detailed structural analyses and zircon U/Pb dating suggest that the coastal Pilbara terrane records two phases of deformation. The first phase is an immature island arc and micro-continental crust collision and is represented by top to the northwest thrusting (D1, circa 3100--3020 Ma). This phase of deformation (an arc-continent collision) appears to represent an important transition in the formation of continental crust. The 3020 Ma granite-porphyry event may be related to syn-post collision igneous activity and may reflect a second crustal thickening associated with magmatic underplating. The second phase of deformation is characterized by regional-scale left-lateral strike-slip faulting (D2, circa 3020--2925 Ma) and by more localized right-lateral strike-slip faulting (D3, circa 2925--2770 Ma). This phase of craton-scale strike-slip faulting may represent stabilization of the newly formed continental crust. |
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Abstract |
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Keywords
Tectonophysics, Continental tectonics--general, Tectonophysics, Evolution of the Earth, Tectonophysics, Continental contractional orogenic belts |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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