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Pillow lavas: comparaisons entre le paléovolcanisme et les coulées des dorsales océaniques

ContributorsKunz, Pierre
Publication date1991
Abstract

The structure, the construction and the emplacement of paleovolcanic submarine units are presented through comparisons with recent flows, observed and sampled on active oceanic ridges. The chosen sites are situated: in mesozoic ophiolitic complexes showing well-preserved volcanic morphologies (French and Swiss Alps), in quaternary shallow-water flows (Sicily, Italy) and on the East Pacific Rise at 13°N. Various factors governing the effusion of submarine flows are discussed: depth of water, underlying topography, rate of effusion, viscosity of lava, piles construction, formation of breccias, gravity transports, presence of hyaloclastites. The sampled rocks are olivine + plagioclase (±Cpx) basalts; these are all MORB-type tholeiites, but etnean lavas tend to within-plate transitional basalts. Looking at the interior of the lava tubes, petrographic data on spherolitic/variolitic rim-textures, allow to follow the crystallization and growth of variolites from abyssal recent flows to ancient weathered volcanic units, where they are especially well developed.

eng
Keywords
  • Submarine volcanism
  • Paleovolcanism
  • Pillow lavas
  • Ophiolites
  • East Pacific Rise
Citation (ISO format)
KUNZ, Pierre. Pillow lavas: comparaisons entre le paléovolcanisme et les coulées des dorsales océaniques. In: Schweizerische mineralogische und petrographische Mitteilungen, 1991, vol. 71, p. 287–293. doi: 10.5169/seals-54364
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Article (Published version)
accessLevelPublic
Identifiers
ISSN of the journal0036-7699
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