Dykes, faults and palaeostresses in the Teno and Anaga massifs of Tenerife (Canary Islands)

Marinoni, Laura; Guðmundsson, Ágúst

doi:10.1016/s0377-0273(00)00217-1

Cited by 71 publications

(51 citation statements)

References 28 publications

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“…The direction of extension in southern Anaga is hence WSW-ENE. Based on two road profiles, Marinoni and Gudmundsson (2000) calculated a horizontal extension of ca. 160 m for southern Anaga in direction 60 , and a horizontal extension in direction 145 of ca.…”

Section: Atypical Rifting In the South?mentioning

confidence: 99%

Rift zone reorganization through flank instability in ocean island volcanoes: an example from Tenerife, Canary Islands

et al. 2004

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The relationship between rift zones and flank instability in ocean island volcanoes is often inferred but rarely documented. Our field data, aerial image analysis, and 40 Ar/ 39 Ar chronology from Anaga basaltic shield volcano on Tenerife, Canary Islands, support a rift zoneflank instability relationship. A single rift zone dominated the early stage of the Anaga edifice (~6-4.5 Ma). Destabilization of the northern sector led to partial seaward collapse at about~4.5 Ma, resulting in a giant landslide. The remnant highly fractured northern flank is part of the destabilized sector. A curved rift zone developed within and around this unstable sector between 4.5 and 3.5 Ma. Induced by the dilatation of the curved rift, a further rift-arm developed to the south, generating a threearmed rift system. This evolutionary sequence is supported by elastic dislocation models that illustrate how a curved rift zone accelerates flank instability on one side of a rift, and facilitates dike intrusions on the opposite side. Our study demonstrates a feedback relationship between flank instability and intrusive development, a scenario probably common in ocean island volcanoes. We therefore propose that ocean island rift zones represent geologically unsteady structures that migrate and reorganize in response to volcano flank instability.

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Section: Atypical Rifting In the South?mentioning

confidence: 99%

Rift zone reorganization through flank instability in ocean island volcanoes: an example from Tenerife, Canary Islands

et al. 2004

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“…While arrested dykes are commonly observed in eroded parts of volcanic edifices, observed feeder dykes are rare 3684 I. Galindo and A. Gudmundsson: Basaltic feeder dykes in rift zones (Gudmundsson, 1986(Gudmundsson, , 2002Marinoni and Gudmundsson, 2000;Geshi et al, 2010Geshi et al, , 2012. Some feeder dykes have been reported from Iceland, Italy, USA, Japan and the Canary Islands (Saemundsson, 1967;Jonsson, 1978;Atkinson and Lambert, 1990;Gudmundsson, 1986Gudmundsson, , 2002Goto et al, 1990;Galindo, 2005;Gudmundsson et al, 2008;Keating et al, 2008;Geshi et al, 2010Geshi et al, , 2012.…”

Section: Introductionmentioning

confidence: 99%

Basaltic feeder dykes in rift zones: geometry, emplacement, and effusion rates

Galindo

Guðmundsson

2012

Nat. Hazards Earth Syst. Sci.

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Abstract. Most volcanic hazards depend on an injected dyke reaching the surface to form a feeder. Assessing the volcanic hazard in an area is thus related to understanding the condition for the formation of a feeder dyke in that area. For this latter, we need good field data on feeder dykes, their geometries, internal structures, and other characteristics that distinguish them from non-feeders. Unfortunately, feeder dykes are rarely observed, partly because they are commonly covered by their own products. For this reason, outcrops are scarce and usually restricted to cliffs, ravines, and man-made outcrops. Here we report the results of a study of feeder dykes in Tenerife (Canary Islands, Spain) and Iceland, focusing on their field characteristics and how their propagation is affected by existing structures. Although Holocene fissure eruptions have been common in both islands, only eleven basaltic feeder dykes have been identified: eight in Tenerife and three in Iceland. They are all well preserved and the relation with the eruptive fissure and/or the deposits is well exposed. While the eruptive fissures are generally longer in Iceland than in Tenerife, their feeders show many similarities, the main ones being that the feeder dykes (1) are generally sheet-shaped; (2) are segmented (as are the associated volcanic fissures); (3) normally contain elongated (prolate ellipsoidal) cavities in their central, topmost parts, that is, 2-3 m below the surface (with solidified magma drops on the cavity walls); (4) contain vesicles which increase in size and number close to the surface; (5) sometimes inject oblique dyke fingers into the planes of existing faults that cross the dyke paths; and (6) may reactivate, that is, trigger slip on existing faults. We analyse theoretically the feeder dyke of the 1991 Hekla eruption in Iceland. Our results indicate that during the initial peak in the effusion rate the opening (aperture) of the feeder dyke was as wide as 0.77 m, but quickly decreased to about 0.56 m. During the subsequent decline in the effusion rate to a minimum, the aperture decreased to about 0.19 m. At a later abrupt increase in the effusion rate, the feeder-dyke opening may have increased to about 0.34 m, and then decreased again as the effusion rate gradually declined during the end stages of the eruption. These thickness estimates fit well with those of many feeders in Iceland and Tenerife, and with the general dyke thickness within fossil central volcanoes in Iceland.

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“…(i.e. : Schmincke, 1967;Hernán, 1976;Féraud et al, 1985;Stillman, 1987;Schirnick et al, 1999;Marinoni and Gudmunsson, 2000).…”

Section: Introductionunclassified

Dike-swarms, key to the reconstruction of major volcanic edifices: The basic dikes of La Gomera (Canary Islands)

Ancochea

Brändle

Huertas

et al. 2008

Journal of Volcanology and Geothermal Research

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The detailed study of the age and distribution of the basic dikes of La Gomera (Canary Islands) has allowed us to reconstruct the evolution of its main volcanic edifice. The dikes of the oldest unit (the Basal Complex) have a N70°-80°dominant direction at regional scale. On the other hand, the dikes of the post Basal Complex subaerial units are the result of local stress fields. The oldest swarm is composed of sills dated at 10.2-9.3 Ma. Four younger radial dike swarms have been identified (S1, S2, S3 and S4) with ages of 9.1-8.4 Ma; 8.2-6.7 Ma; 5.5-4.4 Ma and 5.3-4.0 Ma respectively. The reconstruction of the magmatic focus location using these swarms shows a migration southwards with an average speed of 1.6 mm/year. This temporal sequence of parallel swarms, sills and radial swarms is a pattern frequently repeated during the building of large insular volcanic edifices in the Canary Islands as well as in other archipelagos.

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Dykes, faults and palaeostresses in the Teno and Anaga massifs of Tenerife (Canary Islands)

Cited by 71 publications

References 28 publications

Rift zone reorganization through flank instability in ocean island volcanoes: an example from Tenerife, Canary Islands

Rift zone reorganization through flank instability in ocean island volcanoes: an example from Tenerife, Canary Islands

Basaltic feeder dykes in rift zones: geometry, emplacement, and effusion rates

Dike-swarms, key to the reconstruction of major volcanic edifices: The basic dikes of La Gomera (Canary Islands)

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