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Macquarie Island's Finch-Langdon fault: A ridge-transform inside-corner structure
journal contribution
posted on 2023-05-17, 08:44 authored by Wertz, KL, Mosher, S, Daczko, NR, Mike CoffinMike CoffinABSTRACT Macquarie Island consists of uplifted oceanic crust, uniquely situated in the ocean basin where it formed, thus allowing onshore structures to be placed into their regional oceanic tectonic context. The Finch-Langdon fault, the most significant spreading-related structure on the island, juxtaposes upper-crust rocks against lowercrust and upper-mantle rocks. It consists of dominantly oblique strike-slip, northwest-, west-northwest–, and north-northeast–striking fault segments that bear hydrothermal mineralization indicative of faulting during seafloor spreading. Talus breccias and graywackes overlain by volcanic flows proximal to the fault indicate a long-lived submarine fault scarp that exposed diabase dikes and gabbros during volcanism. Swath reflectivity and bathymetry reveal ridge-parallel spreading fabric and perpendicular fracture zones, the closest ;7 km east of the island. On the basis of field and swath data, we propose that this fault zone formed near the inside corner of a ridge-transform intersection and that structures on the island are conformablconformable with those in the surrounding seafloor.
History
Publication title
Geology (Boulder)Volume
31Issue
8Pagination
661-664ISSN
0091-7613Department/School
Institute for Marine and Antarctic StudiesPublisher
Geological Soc AmericaPlace of publication
Inc, Po Box 9140, Boulder, USA, Co, 80301-9140Rights statement
Copyright © 2003 Geological Society of AmericaRepository Status
- Restricted