A model for radial dike emplacement in composite cones based on observations from Summer Coon volcano, Colorado, USA

Poland, Michael P.; Moats, William P.; Fink, Jonathan

doi:10.1007/s00445-007-0175-9

Cited by 54 publications

(56 citation statements)

References 66 publications

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“…Magma conduits may be cylindrical, such as the main vents of Etna, Stromboli and Reunion, or tabular or sheet-like, such as many that feed fissure eruptions in rift zones in the USA, Japan, the Canary Islands and Iceland (e.g., Pollard et al, 1983;Delaney and Gartner, 1997;Gudmundsson, 2002;Acocella and Neri, 2003;Gudmundsson et al, 2008;Keating et al, 2008;Poland et al, 2008;Geshi et al, 2010. The solidification of magma inside these conduits forms plugs and feeder dykes, respectively.…”

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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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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“…These factors may induce significant deviations from the expected radial pattern of dikes within stratovolcanoes (e.g. Poland et al 2008), explaining the more complex patterns observed in the eroded portions of Etna and Somma-Vesuvius. Fig.…”

Section: Discussionmentioning

confidence: 96%

“…While (a) may explain the radial orientation of the vertically propagating dikes, (b) may indirectly explain the predominance of laterally propagating radial dikes that do not appear to have experienced shallow re-orientation, whose development is commonly expected in stratovolcanoes (e.g. Ode 1957;Poland et al 2008).…”

Section: Discussionmentioning

confidence: 98%

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Dike propagation within active central volcanic edifices: constraints from Somma-Vesuvius, Etna and analogue models

Acocella

Neri

Sulpizio³

2008

Bull Volcanol

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Dikes within stratovolcanoes are commonly expected to have radial patterns. However, other patterns may also be also found, due to regional stresses, magmatic reservoirs, topographic variations. Here we investigate dike patterns within volcanic edifices, by studying dike and fissure complexes at Somma-Vesuvius and Etna (Italy) and using analogue models. At the surface, the dikes and fissures show a radial configuration. At depths of tens to several hundreds of m, in areas exposed by erosion, tangential and oblique dikes are also present. Analogue models indicate that dikes approaching the flanks of cones, regardless of their initial orientation, reorient to become radial (parallel to the maximum gravitational stress). This reorientation is a significant process in shallow magma migration and may also control the emplacement of dike-fed fissures reaching the lower slopes of the volcano

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“…The number of radial dikes emanating from magma chambers was counted for this paper along several circular traverses around magma chambers from terrestrial and inferred venusian radial dike complexes. Terrestrial radial dike swarms include Summer Coon Volcano, Colorado (Poland et al, 2008), Mauna Loa, Hawaii (Lockwood and Lipman, 1987), and Dike Mountain, Colorado (Johnson, 1970). Radial structures were counted around the example of the venusian nova given by Head et al (2009).…”

Section: Graben As Surface Expressions Of Dikes At Depthmentioning

confidence: 99%