A Terminology for Pyroclastic Deposits

Wright, J. W.; Smith, A. L.; Self, Stephen

doi:10.1007/978-94-009-8537-7_33

Cited by 45 publications

(50 citation statements)

References 12 publications

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“…In the case of most volcanological terms, a consensus has been reached and we follow terminology used by prominent authors of textbooks and reviews [13,14,[16][17][18][19][20][21][22][28][29][30][31][32][33]. As far as volcanic forms are concerned, such a consensus has not been always reached with those authors, and we shall define each type of volcanic form before proceeding with its characterization in the CPR.…”

Section: Terminologymentioning

confidence: 99%

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

et al. 2010

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Neogene to Quaternary volcanic/magmatic activity in the Carpathian-Pannonian Region (CPR) occurred between 21 and 0.1 Ma with a distinct migration in time from west to east. It shows a diverse compositional variation in response to a complex interplay of subduction with roll-back, back-arc extension, collision, slab break-off, delamination, strike-slip tectonics and microplate rotations, as well as in response to further evolution of magmas in the crustal environment by processes of differentiation, crustal contamination, anatexis and magma mixing. Since most of the primary volcanic forms have been affected by erosion, especially in areas of post-volcanic uplift, based on the level of erosion we distinguish: (1) areas eroded to the basement level, where paleovolcanic reconstruction is not possible; (2) deeply eroded volcanic forms with secondary morphology and possible paleovolcanic reconstruction; (3) eroded volcanic forms with remnants of original morphology preserved; and (4) the least eroded volcanic forms with original morphology quite well preserved. The large variety of volcanic forms present in the area can be grouped in a) monogenetic volcanoes and b) polygenetic volcanoes and their subsurface/intrusive counterparts that belong to various rock series found in the CPR such as calc-alkaline magmatic rock-types (felsic, intermediate and mafic varieties) and alkalic types including K-alkalic, shoshonitic, ultrapotassic and Na-alkalic. The following volcanic/subvolcanic forms have been identified: (i) domes, shield volcanoes, effusive cones, pyroclastic cones, stratovolcanoes and calderas with associated intrusive bodies for intermediate and basic calc-alkaline volcanism; (ii) domes, calderas and ignimbrite/ash-flow fields for felsic calc-alkaline volcanism and (iii) dome flows, shield volcanoes, maars, tuffcone/tuff-rings, scoria-cones with or without related lava flow/field and their erosional or subsurface forms (necks/ plugs, dykes, shallow intrusions, diatreme, lava lake) for various types of K-and Na-alkalic and ultrapotassic magmatism. Finally, we provide a summary of the eruptive history and distribution of volcanic forms in the CPR using several sub-region schemes.

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Section: Terminologymentioning

confidence: 99%

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

et al. 2010

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“…The last term is usually distinguished from fall or flow processes (Wright et al 1980). Vucetich & Pullar (1973) suggested "fall-tephra" and "flow-tephra" but although th~se terms were adopted by some workers they have not been wldely used.…”

Section: Introductionmentioning

confidence: 99%

A review of late Quaternary silicic and some other tephra formations from New Zealand: Their stratigraphy, nomenclature, distribution, volume, and age

Froggatt¹,

Lowe

1990

New Zealand Journal of Geology and Geophysics

412

431

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The stratigraphic relationships and distribution of36 named late Quaternary (~. 50 000 yr B.P.) silicic tephra formations, erupted from 4 volcanic centres-Okataina, Taupo, Maroa, and Tuhua (Mayor Island}-are presented. The stratigraphy and status of several other named late Quaternary tephras are also discussed. This compilation brings together all the data, currently scattered through many publications, to make tephrostratigraphy more accessible and more easily used. The nomenclature of tephra formations is discussed and some rationalisations are suggested. The term "tephrology" is suggested as an appropriate title for the field of tephra studies. The deletion of grain-size (ash, lapi1li), shape (breccia), and lithologic (pumice) terms from all formation names is recommended, as is standardisation on a "Tephra Formation" formal Several tephra layers not previously formally named, or without designated type sections, are defined. The dominant ferromagnesian mineral assemblage of each tephra formation has been compiled as an aid to tephra identification. All available radiocarbon ages (384) on each tephra formation are presented, and each age is assessed for reliability in dating the eruption of that tephra. The standard-deviation weighted mean age of the reliable ages has been determined as the best current estimate of the age of each tephra. At least 10 tephra formations have no reliable ages, and efforts should be made to date these.

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“…La zone encadrée représente la région d'étude. A) Dépôt de retombé; B) Dépôt de coulée; C) Dépôt de déferlante (Wright et al, 1980). .…”

Section: Liste Des Figuresunclassified

Étude volcano-sédimentaire de la zone de transition sommitale du Groupe de Hunter Mine et de la partie basale du Groupe de Stoughton-Roquemaure Abitibi Québec

Caron¹

2000

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IV REMERCIEMENTSJe voudrais tout d'abord remercier ma famille pour leur soutient moral au cours de ce projet de maîtrise. Il est également important de souligner le soutient financier de Noranda Exploration sans quoi ce projet n'aurait put être réalisé. De plus, il m'aurait été impossible de mettre à terme ce mémoire sans la confiance, la patience et l'intérêt porté à ce projet de mon directeur de recherche, M. Wulf Mueller (UQAC) Franklin, 1987;Franklin, 1990). Tableau 9 : Dépôts associés aux principaux faciès volcaniques des 161 Centres éruptifs des volcans composites sous-marins. (Modifié de Easton et Johns, 1986). , 1980;Dimroth et al., 1982;Dimroth et al., 1985). Cet intérêt s'est accru au cours des dernières années puisque le nombre de découvertes de gîtes importants près de la surface a fortement diminué (Mueller, 1994). Conséquemment, une meilleure compréhension des environnements de formation des roches hôtes associées aux gisements est critique particulièrement à l'égard des gisements de sulfures volcanogènes. En effet, ce type de minéralisation est communément associé aux séquences pyroclastiques et volcanoclastiques marines. C'est pour ces diverses raisons que ce mémoire a été fait dans la zone de transition (Mueller, 1994).. 22 LISTE DES FIGURES Analogues modernes et caractéristiques généralesLes analogues modernes des édifices volcaniques abitibiens se trouvent entre 500 et 3500 m de profondeur dans les bassins arrière-arc ou aux arcs de Izu-Bonin (Smith et al., 1990) (Mueller, 1994). La signature géochimique de ces édifices est beaucoup plus variée que celle des dorsales médio-océanique à l'exception de l'Islande où il y a convergence du volcanisme de dorsale médio-océanique avec un volcanisme de point chaud (Mueller, 1994).La localisation des édifices volcaniques reliés aux arcs modernes est contrôlée par la géométrie de l'arc et par les structures en extension associées, qui sont communément en échelons. Les structures en extension, comme les failles synvolcaniques, favorisent la montée du magma. Les "zones de transfert" ou "d'accommodation" adjacentes aux arcs insulaires comme celui d'Izu-Bonin entre les îles de Simisu Sud et de Kotori, représentent un lieu de changement du comportement structural. Ces zones de transfert peuvent également être des foyers de formation des édifices volcaniques (Taylor et al., 1990;Mueller, 1994). ObjectifsLe but principal de ce projet de maîtrise est de déterminer la paléogéographie de la zone de transition du Groupe de Hunter Mine en caractérisant les volcanites hôtes qui sont associées aux indices de sulfures massifs volcanogènes de type Mattabi et aux formations de fer rubanées. Pour parvenir à déterminer la paléogéographie, il sera important de procéder par des objectifs spécifiques tels que : A) -la définition du contexte géologique en utilisant la volcanologie et la sédimentologie physique ; B) -la détermination des processus de formation des volcanites à l'aide de travaux de terrain et de laboratoire tels que; 1) la cartographie des zones d...

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A Terminology for Pyroclastic Deposits

Cited by 45 publications

References 12 publications

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

Neogene-Quaternary Volcanic forms in the Carpathian-Pannonian Region: a review

A review of late Quaternary silicic and some other tephra formations from New Zealand: Their stratigraphy, nomenclature, distribution, volume, and age

Étude volcano-sédimentaire de la zone de transition sommitale du Groupe de Hunter Mine et de la partie basale du Groupe de Stoughton-Roquemaure Abitibi Québec

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