Gravitational spreading controls rift zones and flank instability on El Hierro, Canary Islands
By: Munn, Sebastian
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Contributor(s): Walter, Thomas R | Klugel, Andreas.
Material type: 
ArticleDescription: 257-268pp ; Illustration.Subject(s): Rift zones | Volcano-tectonic structure | Gravity tectonics | Structural geology | Experimental studies
In:
Geological magazine : Vol. 143 Iss. 1-6 Year. 2006Summary: Ocean island volcanoes frequently develop local rift zones associated with flank movement and flank collapses. The ocean island El Hierro grew by coalescence and collapse of three volcanic edifices, which are an elongated topographic ridge (the Southern Ridge) and two semi-circular volcanic cones (Tiñor volcano, El Golfo volcano). During edifice growth and volcano coalescence, eruption fissures nucleated into rift zones that developed a complex triangle pattern. In scaled analogue experiments we could successfully reproduce the geometry of rift zones and unstable flanks as observed on El Hierro. The experimental results suggest that the rift configuration on El Hierro is the result of gravitational volcano spreading over deformable basal substrata, rather than of deep-seated magma updoming as thought previously. This paper elucidates the importance of the basal substratum and gravitational spreading, and the relationship to rifting and flank instability on El Hierro Island, and may help in understanding similar volcano architectures elsewhere.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Article
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Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002538_36 | ||
Serials/Scientific Journal
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Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002538 |
Ocean island volcanoes frequently develop local rift zones associated with flank movement and flank collapses. The ocean island El Hierro grew by coalescence and collapse of three volcanic edifices, which are an elongated topographic ridge (the Southern Ridge) and two semi-circular volcanic cones (Tiñor volcano, El Golfo volcano). During edifice growth and volcano coalescence, eruption fissures nucleated into rift zones that developed a complex triangle pattern. In scaled analogue experiments we could successfully reproduce the geometry of rift zones and unstable flanks as observed on El Hierro. The experimental results suggest that the rift configuration on El Hierro is the result of gravitational volcano spreading over deformable basal substrata, rather than of deep-seated magma updoming as thought previously. This paper elucidates the importance of the basal substratum and gravitational spreading, and the relationship to rifting and flank instability on El Hierro Island, and may help in understanding similar volcano architectures elsewhere.
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