Influence de la Nature des Magmas sur l’Activité Phréatomagmatique: Approche Volcanologique et Thermodynamique

Boivin, Pierre; Bourdier, Jean-Louis; Camus, G.; Hervé, Alan; Gourgaud, Alain; Kieffer, Guy; Margat, Jean; Vincent, Pierre; Auby, R.

doi:10.1007/bf02600387

Cited by 14 publications

(19 citation statements)

References 11 publications

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“…The youngest craters have diameter/depth ratios between 3 and 7 (dashed lines). Data sources: Asososca (Nicaragua) - Pardo et al (2008); Atexcac (Mexico) -Carrasco-Núñez et al (2007); Eledoi (Tanzania) - Dawson and Powell (1969); Elegante and Molina North (Mexico) - Wood (1974) and Gutmann (1976); Gour de Tazenat, Lac D'issarlès and Lac Pavin (France) -crater dimensions from Noll (1967), country rock descriptions from Juvigé et al (1993), Bozon (1963) and Boivin et al (1982), respectively; Joya Honda (Mexico) -Aranda- Gómez and Luhr (1996); Nilahue (Chile) - Muller and Veyl (1956); PAVF East Maar -this study; Tecuitlapa (Mexico) -Ort and Carrasco-Núñez (2009); Ubehebe (California, USA) - Crowe and Fisher (1973); Ukinrek West and Ukinrek East (Alaska) - Kienle et al (1980); hard substrate maars from the West Eifel volcanic field (Germany) -Büchel (1993). In the West Eifel, as in other volcanic fields, older maars tend to be shallower than young maars for a certain diameter, due to erosion.…”

Section: Discussionmentioning

confidence: 99%

Influence of the substrate on maar–diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

Ross

Delpit

Haller

et al. 2011

Journal of Volcanology and Geothermal Research

101

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The morphologic parameters, pyroclastic deposits and evolution of maar-diatreme volcanoes are affected by the type of environment in which they are emplaced. End-member cases are a hard substrate (rocks) and a soft substrate (unconsolidated volcaniclastic or sedimentary deposits). In this paper, we present an example of a volcanic complex emplaced in a mixed hard-soft setting from the Pali Aike volcanic field (PAVF) near the Argentina-Chile border. The PlioPleistocene PAVF is an alkaline, mafic, back-arc monogenetic field which contains over 100 phreatomagmatic volcanoes. The studied volcanic complex contains two large coalescent maars overlain by scoria and spatter. The 1.4x1.3 km East Maar has better exposures than the shallower, 1.9 km-wide West Maar and seems to have been less modified by post-eruptive processes. The tephra rim of the East Maar was studied in detail and we infer it was produced mostly by base surges from phreatomagmatic eruption columns, with rare instances of intercalated scoria fall layers. Based on regional information, the general pre-maar stratigraphy is dominated by sedimentary and volcaniclastic rocks of the Magallanes Basin, including a thick poorly consolidated upper unit dating from the Miocene. These are overlain by Plio-Pleistocene fluvio-glacial deposits and PAVF lavas, some of which are exposed in the East Maar just below the phreatomagmatic deposits. All of these units are represented as lithic clasts in the tephra rim of the East Maar, the most abundant being the clasts from the earlier basaltic lavas and rock fragments derived from the glacial deposits. There is no specific evidence for a deep diatreme under the East Maar, and in this particular case, the mixed environment seems to have produced a maar-diatreme volcano typical of a soft substrate.

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Section: Discussionmentioning

confidence: 99%

Influence of the substrate on maar–diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

Ross

Delpit

Haller

et al. 2011

Journal of Volcanology and Geothermal Research

101

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“…The first phreato-magmatic phase produced pumiceous lapilli-bearing ash deposits (LM in D'Oriano et al 2005; Units I-II in Di Vito et al 1987) that built the cone. The main LM deposit is composed of coarse to fine ash and is coarser and lapilli bearing in the lowermost levels (Unit I), where it is intercalated with pumice or scoria lenses or beds (Boivin et al 1982). This deposit was emplaced by pyroclastic flows.…”

Section: Volcanological Background the Monte Nuovo Eruptionmentioning

confidence: 99%

Constraining pre-eruptive magma conditions and unrest timescales during the Monte Nuovo eruption (1538 ad; Campi Flegrei, Southern Italy): integrating textural and CSD results from experimental and natural trachy-phonolites

et al. 2016

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We present crystallization experiments representing a broad range of growth conditions of alkali feldspar and sodalite in a trachy-phonolite magma composition during later stages of evolution. Our results include (i) textural data and mineral assemblages of synthetic samples; (ii) feldspar nucleation kinetics and growth rate estimates; and (iii) textural data, mineral abundances, and crystal size distribution measurements on samples representative of the Monte Nuovo eruption (1538 AD), the last eruption of Campi Flegrei, Southern Italy. Experiments reproduced the texture and feldspar content of natural products indicating that kinetic data can provide insights into processes within the volcanic system shortly before and during this small-magnitude eruption and, particularly, about magma ascent timescale. We suggest that the groundmass crystallization of Monte Nuovo magma started between 4 and 7 km depth (∼100-200 MPa) at a temperature between 825 and 840°C (close to the liquidus of alkali feldspar). The crystallization kinetics of alkali feldspar and the absence of sodalite in most of the natural samples indicate that magma ascent rate increased in the shallow part of the conduit from about 3 km depth to the quenching level (possibly fragmentation point; ∼30 MPa), during the first phases of the eruption.The crystallization time of the magma requires that it ascended from pre-eruptive storage to the quenching level in several hours to a few days. We also observe that a small decrease in pressure can induce a dramatic increase in crystallinity, with associated rheological changes, leading to changes in the eruption style, and such changes could occur on timescales of hours to several days. The products from the later phases of the Monte Nuovo eruption are more crystalline and contain sodalite in response to the decrease in magma ascent rate, which in turn allowed for more degassing during ascent, resulting in more time spent at very shallow depths.

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“…According to de Ramond (1815), Lemptégy was already being excavated for its scoria in the early nineteenth century. He noted that Lemptégy was at fi rst considered as a trachyte hill due to its mantling by a trachytic pyroclastic deposit (the Puy Chopine deposit; Boivin et al 2009a), but the early quarrying uncovered the basaltic scoria interior. Immediately after WWII, excavation began in earnest to provide material for reconstruction, and work continued until 2007.…”

Section: Lemptégy Quarrymentioning

confidence: 99%

“…Early Lemptégy, referred to as Lemptégy 1, consists of a trachybasaltic cinder cone (Table 1; De Goër de Hervé et al, 1999;Boivin et al, 2009a) and formed a number of vents and lava fl ows (Figs. 2 and 3).…”

Section: Lemptégymentioning

confidence: 99%

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Endogenous and exogenous growth of the monogenetic Lemptégy volcano, Chaîne des Puys, France

Delcamp

Vries

Stéphane³

et al. 2014

Geosphere

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International audienceThe monogenetic Lemptégy volcano in the Chaîne des Puys (Auvergne, France) was quarried from 1946 to 2007 and offers the possibility to study scoria cone architecture and evolution. This volcano was originally 50–80 m high, but scoria excavation has resulted in a 50-m-deep hole. eginning in the 1980s, extraction was carried out with the advice of volcanologists so that Lemptégy’s shallow plumbing system and three-dimensional stratigraphy have been preserved. Detailed mapping enabled key stratigraphic units to be distinguished and the constructional phases to be reconstructed. The emplacement and evolution of the shallow plumbing system have also been unraveled. The growth of this monogeneticscoria cone included two temporally well-separated eruptions from closely spaced vents. The activity included Hawaiian, Strombolian and Vulcanian explosions, lava effusion, cryptodome and dome formation, partial collapse, satellite vent formation, eruptive pauses, and intrusion emplacement with consequent uplift. The cone shape, structure, and hence the local stress fi eld, plumbing system, and thermal state were continuously hanging,which in turn infl uenced the eruptive style and location. The plumbing system morphology and microtectonic structures both record local stress fi eld and magmatic fl ow directionchanges. Lemptégy volcano’s internal architecture,stratigraphy, and evolution show howcomplex a monogenetic volcano can be

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Influence de la Nature des Magmas sur l’Activité Phréatomagmatique: Approche Volcanologique et Thermodynamique

Cited by 14 publications

References 11 publications

Influence of the substrate on maar–diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

Influence of the substrate on maar–diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

Constraining pre-eruptive magma conditions and unrest timescales during the Monte Nuovo eruption (1538 ad; Campi Flegrei, Southern Italy): integrating textural and CSD results from experimental and natural trachy-phonolites

Endogenous and exogenous growth of the monogenetic Lemptégy volcano, Chaîne des Puys, France

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