Journal of geomagnetism and geoelectricity
Online ISSN : 2185-5765
Print ISSN : 0022-1392
Late Jurassic and Early Cretaceous Evolution of the Western Central Pacific Ocean
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1976 年 28 巻 3 号 p. 219-236


The Phoenix lineations are a set of east-west trending magnetic anomalies that recorded sea-Boor spreading in the Nauru and Central Pacific Basins of the western Pacific from the Late Jurassic through the Early Cretaceous. The northern portions of these basins near the Marshall-Gilbert Islands are characterized by a magnetic quiet zone that presumably formed in the Late Jurassic prior to M25 (153m. y.). In the eastern part of the Central Pacific Basin just east of Magellan Rise is a northwest trending M11 (126m. y.) to M4 (117m. y.) anomaly sequence. The geometry and spreading rates associated with the east-west trending Phoenix lineations and the Hawaiian lineations to the north suggest that the two patterns met at a fault-fault-ridge triple junction from M25 (153m. y.) until M14 (131m. y.) time. This system underwent a readjustment between M14 and M10 time that transferred the Magellan Rise from the Phoenix plate to the Pacific plate and established two triple junctions in place of the previous one. A stable fault-fault-ridge junction formed just southeast of Magellan Rise to connect the east-west and northwest trending Phoenix lineations, while a slow-spreading, ridge-ridge-ridge junction broke the original Pacific plate in two from at least M11 to M4 time and was responsible for the formation of the Mid-Pacific Mountains.

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