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Speculations on Cretaceous tectonic history of the Northwest Pacific and a tectonic origin for the Hawaii Hotspot

Ian O. Norton
Speculations on Cretaceous tectonic history of the Northwest Pacific and a tectonic origin for the Hawaii Hotspot (in Plates, plumes, and planetary processes, Gillian R. Foulger (editor) and Donna M. Jurdy (editor))
Special Paper - Geological Society of America (2007) 430: 451-470

Abstract

Current interpretations of Cretaceous tectonic evolution of the northwest Pacific trace interactions between the Pacific plate and three other plates, the Farallon, Izanagi, and Kula plates. The Farallon plate moved generally eastward relative to the Pacific plate. The Izanagi and Kula plates moved generally northward relative to the Pacific plate, with Izanagi the name given to the northward-moving plate prior to the Cretaceous normal polarity superchron and the name Kula applied to the postsuperchron plate. In this article I suggest that these names apply to the same plate and that there was only one plate moving northward throughout the Cretaceous. I suggest that the tectonic reorganization that has previously been interpreted as formation of a new plate, the Kula plate, at the end of the superchron was actually a plate boundary reorganization that involved a 2000 km jump of the Pacific-Farallon-Kula/Izanagi triple junction. Because this jump occurred during a time of no magnetic reversals, it is not possible to map or date it precisely, but evidence suggests mid-Cretaceous timing. The Emperor Trough formed as a transform fault linking the locations of the triple junction before and after the jump. The triple junction jump can be compared with an earlier jump of the triple junction of 800 km that has been accurately mapped because it occurred during the Late Jurassic formation of the Mesozoic-sequence magnetic lineations. The northwest Pacific also contains several volcanic features, such as Hawaii, that display every characteristic of a hotspot, although whether deep mantle plumes are a necessary component of hotspot volcanism is debatable. Hawaiian volcanism today is apparently independent of plate tectonics, i.e., Hawaii is a center of anomalous volcanism not tied to any plate boundary processes. The oldest seamounts preserved in the Hawaii-Emperor chain are located on Obruchev Rise at the north end of the Emperor chain, close to the junction of the Aleutian and Kamchatka trenches. These seamounts formed in the mid-Cretaceous close to the spreading ridge abandoned by the 2000 km triple junction jump. Assuming that Obruchev Rise is the oldest volcanic edifice of the Hawaiian hotspot and thus the site of its initiation, the spatial and temporal coincidence between these events suggests that the Hawaii hotspot initiated at the spreading ridge that was abandoned by the 2000 km jump of the triple junction. This implies a tectonic origin for the hotspot. Other volcanic features in the northwest Pacific also appear to have tectonic origins. Shatsky Rise is known to have formed on the migrating Pacific-Farallon-Izanagi triple junction during the Late Jurassic-Early Cretaceous, not necessarily involving a plume-derived hotspot. Models for the formation of Hess Rise have included hotspot track and anomalous spreading ridge volcanism. The latter model is favored in this article, with Hess Rise forming on a ridge axis possibly abandoned as a result of a ridge jump during the superchron. Thus, although a hotspot like Hawaii could be associated with a deep mantle plume today, it would appear that it and other northwest Pacific volcanic features originally formed as consequences of shallow plate tectonic processes.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 430
Title: Speculations on Cretaceous tectonic history of the Northwest Pacific and a tectonic origin for the Hawaii Hotspot
Title: Plates, plumes, and planetary processes
Author(s): Norton, Ian O.
Author(s): Foulger, Gillian R.editor
Author(s): Jurdy, Donna M.editor
Affiliation: ExxonMobil Upstream Research, Houston, TX, United States
Affiliation: Durham University, Department of Earth Sciences, Durham, United Kingdom
Pages: 451-470
Published: 2007
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 73
Accession Number: 2008-045023
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch map
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200813
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