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Geological constrai...
Geological constraints on the dynamic emplacement of cone-sheets - The Ardnamurchan cone-sheet swarm, NW Scotland
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- Mathieu, Lucie (författare)
- Univ Quebec Chicoutimi, CONSOREM, Chicoutimi, PQ G7H 2B1, Canada.;Uppsala Univ, Dept Earth Sci, CEMPEG, S-75236 Uppsala, Sweden.
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- Burchardt, Steffi (författare)
- Uppsala universitet,Mineralogi, petrologi och tektonik
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- Troll, Valentin (författare)
- Uppsala universitet,Mineralogi, petrologi och tektonik,CEMPEG
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- Krumbholz, Michael (författare)
- Uppsala universitet,Mineralogi, petrologi och tektonik
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- Delcamp, Audray (författare)
- Vrije Univ Brussel, Fac Sci, Dept Geog, B-1050 Brussels, Belgium.
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Univ Quebec Chicoutimi, CONSOREM, Chicoutimi, PQ G7H 2B1, Canada;Uppsala Univ, Dept Earth Sci, CEMPEG, S-75236 Uppsala, Sweden. Mineralogi, petrologi och tektonik (creator_code:org_t)
- Elsevier BV, 2015
- 2015
- Engelska.
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Ingår i: Journal of Structural Geology. - : Elsevier BV. - 0191-8141 .- 1873-1201. ; 80, s. 133-141
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Cone-sheets are a significant constituent of many central volcanoes, where they contribute to volcano growth by intrusion and through flank eruptions, although the exact emplacement mechanisms are still controversially discussed. In particular, it is not yet fully resolved whether cone-sheets propagate as magma-driven, opening-mode fractures or as shear fractures, and to what extent pre-existing host-rock structures and different stress fields influence cone-sheet emplacement. To shed further light on the role of these parameters in cone-sheet emplacement, we use detailed field and remote sensing data of the classic Ardnamurchan cone-sheet swarm in NW-Scotland, and we show that the cone-sheets primarily propagated as opening-mode fractures in the sigma(1)-sigma(2) plane of the volcanic stress field. In addition, more than one third of the Ardnamurchan cone-sheet segments are parallel to lineaments that form a conjugate set of NNW and WNW striking fractures and probably reflect the regional NW SE orientation of sigma(1) during emplacement in the Palaeogene. Cone-sheets exploit these lineaments within the NE and SW sectors of the Ardnamurchan central complex, which indicates that the local volcanic stress field dominated during sheet propagation and only allowed exploitation of host-rock discontinuities that were approximately parallel to the sheet propagation path. In addition, outcrop-scale deflections of cone-sheets into sills and back into cone-sheets (also referred to as "staircase" geometry) are explained by the interaction of stresses at the propagating sheet tip with variations in host-rock strength, as well as the influence of sheet-induced strain. As a consequence, cone-sheets associated with sill-like segments propagate as mixed-mode I/II fractures. Hence, cone-sheet emplacement requires a dynamic model that takes into account stress fields at various scales and the way propagating magma interacts with the host rock and its inherent variations in rock strength.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Multidisciplinär geovetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geosciences, Multidisciplinary (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geology (hsv//eng)
Nyckelord
- Cone-sheets
- Sheet emplacement
- Stress field
- Host-rock structure
- Ardnamurchan
- Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
- Geovetenskap med inriktning mot mineralogi, petrologi och tektonik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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