Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Suhr, G. Articles by Cawood, P. A. Search for Related Content GeoRef GeoRef Citation

Southeastern Lewis Hills (Bay of Islands Ophiolite): Geology of a deeply eroded, inside-corner, ridge-transform intersection

¹ Institut für Mineralogie und Geochemie, Universität zu Köln, Zülpicher Strasse 49b, 50674 Köln, Germany, and Max-Planck- Institut für Chemie, Postfach 3060, 55020 Mainz, Germany
² Tectonics Special Research Centre, School of Applied Geology, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia

The Lewis Hills massif (Bay of Islands Ophiolite, Newfoundland) preserves a deeply eroded transform fault. A major, low-angle, extensional mylonite zone is next to the transform assemblage and probably merges laterally into it. The mylonite developed in a high-temperature environment and occurs at the top of relatively rigid lithospheric mantle. The lithospheric mantle represents exhumed, older, arc-type basement of the Little Port Complex that is also exposed across the transform in the western Lewis Hills. It differs dramatically from an asthenospheric mantle unit of the Bay of Islands Complex, exposed in the eastern Lewis Hills, that formed in a spreading ridge environment.

The fossil ridge-transform segment and associated low-angle normal fault in the Lewis Hills formed at an inside-corner structural setting similar to recently discovered core complexes at oceanic ridge-transform intersections. However, the Lewis Hills segment developed in a setting where a spreading center propagated across a transform margin and rifted older arc-type lithosphere. Factors that contributed to formation of the low-angle detachment fault are the lithospheric nature of the mantle basement, rheological weakening and strain focusing by intrusive sills, and weak lateral coupling realized by the extensional transform assemblage.

Key Words: Bay of Islands Ophiolite • core complexes • detachment faults • igneous intrusions • mylonite • transform faults

This article has been cited by other articles:

				C.R. van Staal, J.B. Whalen, V.J. McNicoll, S. Pehrsson, C.J. Lissenberg, A. Zagorevski, O. van Breemen, and G.A. Jenner The Notre Dame arc and the Taconic orogeny in Newfoundland Geological Society of America Memoirs, January 1, 2007; 200(0): 511 - 552. [Abstract] [Full Text] [PDF]

				J. F. Dewey Inaugural Article: Orogeny can be very short PNAS, October 25, 2005; 102(43): 15286 - 15293. [Abstract] [Full Text] [PDF]

				M. KURTH-VELZ, A. SASSEN, and S. J. G. GALER Geochemical and Isotopic Heterogeneities along an Island Arc-Spreading Ridge Intersection: Evidence from the Lewis Hills, Bay of Islands Ophiolite, Newfoundland J. Petrology, March 1, 2004; 45(3): 635 - 668. [Abstract] [Full Text] [PDF]

				J.-M. Schroetter, P. Page, J. H. Bedard, A. Tremblay, and V. Becu Forearc extension and sea-floor spreading in the Thetford Mines Ophiolite Complex Geological Society, London, Special Publications, January 1, 2003; 218(1): 231 - 251. [Abstract] [PDF]