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TitleA recipe for microcontinent formation
AuthorMuller, R D; Gaina, C; Roest, W R; Hansen, D L
SourceGeology v. 29, no. 3, 2001 p. 203-206,<0203:arfmf>;2
Alt SeriesGeological Survey of Canada, Contribution Series 1999176
PublisherGeological Society of America
Mediapaper; on-line; digital
File formatpdf
AreaSeychelles; Indian Ocean; Norwegian Greenland Sea; Tasman Plateau; Tasman Sea
Lat/Long WENS -30.0000 10.0000 70.0000 60.0000
Lat/Long WENS -30.0000 0.0000 70.0000 60.0000
Lat/Long WENS 55.0000 70.0000 -5.0000 -20.0000
Lat/Long WENS 150.0000 165.0000 -35.0000 -50.0000
Subjectstectonics; continental margins; oceanic crust; accretion; rifting; sea floor spreading; volcanism; crustal models; terranes; microcontinents; plumes
Illustrationsblock diagrams; graphs; sketch maps
AbstractAccreted slivers of continental margins are common in the geologic record, but the processes that lead to their formation are poorly understood. We observe an association of plume-related microcontinent isolation and subsequent long-term asymmetries in oceanic crustal accretion based on four recent examples: the Seychelles in the Indian Ocean, Jan Mayen in the Norwegian-Greenland Sea, and the East Tasman Plateau and the Gilbert Seamount Complex in the Tasman Sea. These microcontinents formed by rerifting of a young continental margin (<25 m.y. old) in the vicinity of a mantle-plume stem, followed by asymmetric seafloor spreading. Two-dimensional numerical stochastic basin modeling suggests that a yield-strength minimum along the landward edge of a rifted margin, thermally enhanced by heating from a mantle plume, may cause a spreading ridge to jump onto this zone of weakness. This action isolates a passive-margin segment. The association of large igneous provinces and microcontinents should be useful for identifying similar events in the geological record.