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Revisiting hotspots and continental breakup; updating the classical three-arm model

Carol A. Stein, Seth Stein, Molly M. Gallahue and Reece P. Elling
Revisiting hotspots and continental breakup; updating the classical three-arm model (in In the footsteps of Warren B. Hamilton; new ideas in earth science, Gillian R. Foulger, Lawrence C. Hamilton, Donna M. Jurdy, Carol A. Stein, Keith A. Howard and Seth Stein)
Special Paper - Geological Society of America (May 2022) 553: 41-57

Abstract

Classic models proposed that continental rifting begins at hotspots-domal uplifts with associated magmatism-from which three rift arms extend. Rift arms from different hotspots link up to form new plate boundaries, along which the continent breaks up, generating a new ocean basin and leaving failed arms, termed aulacogens, within the continent. In subsequent studies, hotspots became increasingly viewed as manifestations of deeper upwellings or plumes, which were the primary cause of continental rifting. We revisited this conceptual model and found that it remains useful, though some aspects require updates based on subsequent results. First, the rift arms are often parts of boundaries of transient microplates accommodating motion between the major plates. The microplates form as continents break up, and they are ultimately incorporated into one of the major plates, leaving identifiable fossil features on land and/or offshore. Second, much of the magmatism associated with rifting is preserved either at depth, in underplated layers, or offshore. Third, many structures formed during rifting survive at the resulting passive continental margins, so study of one can yield insight into the other. Fourth, hotspots play at most a secondary role in continental breakup, because most of the associated volcanism reflects plate divergence, so three-arm junction points may not reflect localized upwelling of a deep mantle plume.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 553
Title: Revisiting hotspots and continental breakup; updating the classical three-arm model
Title: In the footsteps of Warren B. Hamilton; new ideas in earth science
Author(s): Stein, Carol A.Stein, SethGallahue, Molly M.Elling, Reece P.
Author(s): Foulger, Gillian R.
Author(s): Hamilton, Lawrence C.
Author(s): Jurdy, Donna M.
Author(s): Stein, Carol A.
Author(s): Howard, Keith A.
Author(s): Stein, Seth
Affiliation: University of Illinois at Chicago, Department of Earth and Environmental Sciences, Chicago, IL, United States
Affiliation: Durham University, Department of Earth Sciences, Durham, United Kingdom
Pages: 41-57
Published: 20220503
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 119
Accession Number: 2023-028044
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map, sect.
Secondary Affiliation: Northwestern University, USA, United States
Source Note: Special paper 553
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2023, American Geosciences Institute.
Update Code: 2023
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