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Continental breakup in magmatic provinces; an Ethiopian example

C. J. Ebinger and M. Casey
Continental breakup in magmatic provinces; an Ethiopian example
Geology (Boulder) (June 2001) 29 (6): 527-530

Abstract

Mechanical processes largely control the along-axis segmentation of continental rifts; however, asthenospheric processes strongly influence the along-axis segmentation of mid- ocean ridges. We examine the distribution of strain and magmatism in the transitional active Main Ethiopian rift. Magmatic construction, diking, and faulting during the past 1.6 m.y. have created approximately 20-km-wide, approximately 60-km-long magmatic segments with or without axial valleys. Magmatic segments are arranged en echelon within the approximately 100-km-wide rift valley bounded by mid-Miocene border faults. Geodetic data show that magmatic segments accommodate >80% of the strain across the rift, indicating that border faults are no longer the locus of extension. Comparison with mid-ocean ridges suggests that magmatic segments, rather than detachment faults, mark the ocean-continent boundary in rifts with a ready magma supply. Magmatic margins, therefore, may contain detachments abandoned during continental breakup. The processes of localized dike intrusion with underplating would produce strips of mafic crust transitional to oceanic crust, but without coherent seafloor-spreading magnetic anomalies.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 29
Serial Issue: 6
Title: Continental breakup in magmatic provinces; an Ethiopian example
Affiliation: Royal Holloway University of London, Department of Geology, Egham, United Kingdom
Pages: 527-530
Published: 200106
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 39
Accession Number: 2001-043126
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., geol. sketch map
N08°00'00" - N09°00'00", E39°00'00" - E40°00'00"
Secondary Affiliation: University of Leeds, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200113
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