Results 221 to 230 of about 26,308 (272)
Some of the next articles are maybe not open access.
Geological Society, London, Special Publications, 1998
Abstract Our understanding of the spread of volcanic ejecta from eruption columns has evolved significantly since the first quantitative studies. Given recent advances, it is possible to describe much of the physics of tephra dispersal, and to construct a relatively robust model for the spread of tephra in the proximal region of a volcanic ...
openaire +1 more source
Abstract Our understanding of the spread of volcanic ejecta from eruption columns has evolved significantly since the first quantitative studies. Given recent advances, it is possible to describe much of the physics of tephra dispersal, and to construct a relatively robust model for the spread of tephra in the proximal region of a volcanic ...
openaire +1 more source
American Journal of Archaeology, 1974
I. The problem: According to studies on Mediterranean deep-sea cores by Ninkovich and Heezen,' tephra from two violent volcanic eruptions must have fallen on Crete in prehistoric times. The first of these eruptions occurred at least 25,000 years ago, and its tephra apparently fell on all parts of Crete.
Charles J. Vitaliano +1 more
openaire +1 more source
I. The problem: According to studies on Mediterranean deep-sea cores by Ninkovich and Heezen,' tephra from two violent volcanic eruptions must have fallen on Crete in prehistoric times. The first of these eruptions occurred at least 25,000 years ago, and its tephra apparently fell on all parts of Crete.
Charles J. Vitaliano +1 more
openaire +1 more source
1984
The transport modes of subaerial fallout tephra are (1) by ballistic trajectory and (2) by turbulent suspension. Energy is supplied initially to fragments by the eruption and later by wind. Tephra that falls from the atmosphere onto land is called subaerial fallout or airfall tephra.
Richard V. Fisher, Hans-Ulrich Schmincke
openaire +1 more source
The transport modes of subaerial fallout tephra are (1) by ballistic trajectory and (2) by turbulent suspension. Energy is supplied initially to fragments by the eruption and later by wind. Tephra that falls from the atmosphere onto land is called subaerial fallout or airfall tephra.
Richard V. Fisher, Hans-Ulrich Schmincke
openaire +1 more source
Revisiting the Borrobol Tephra
Boreas, 2016The Borrobol Tephra has been identified as one of the key tephra horizons for the Lateglacial time period but it also exemplifies many of the promises and problems of tephrochronology. Additional horizons with similar major element composition and approximately the same age have been identified around the North Atlantic region.
Lind E. M. +3 more
openaire +1 more source
Identité granulométrique de Tephra
Bulletin de l'Association française pour l'étude du quaternaire, 1984L'étude granulométrique (médiane et classement) de la fraction cendreuse (inférieure à 2 mm) des tephra volcaniques (émis par la Montagne Pelée et d'autres volcans andésitiques) permet de distinguer leurs différents dynamismes générateurs. Ainsi quatre grands types peuvent être séparés : • Les retombées ponceuses donnent des dépôts grossiers et ...
Bardintzeff, Jacques-Marie +1 more
openaire +2 more sources
CLASSIFICATION OF TEPHRA-DERIVED SPODOSOLS
Soil Science, 1990There are many tephra-derived soils showing characteristic morphology and chemistry of Spodosols in humid cold climates. We reviewed ICOMOD (International Committee on the Classification of Spodosols) Proposal D by the National Soil Quality Survey Assurrance Staff (1989) using 43 tephra-derived soils from Alaska, the State of Washington, U.S.A., and ...
S. SHOJI, T. ITO
openaire +1 more source
1981
A dark tephra layer, named “a”, is found in soils in East and Northeast Iceland. Its volume is approximately 2 km3 and it covers about 40% of Iceland. An isopach map and grain-size study suggests that the tephra deposit forms a distinctly two-lobed layer and was erupted in the year 1477 from the central volcano Kverkfjoll, at the northern margin of ...
openaire +1 more source
A dark tephra layer, named “a”, is found in soils in East and Northeast Iceland. Its volume is approximately 2 km3 and it covers about 40% of Iceland. An isopach map and grain-size study suggests that the tephra deposit forms a distinctly two-lobed layer and was erupted in the year 1477 from the central volcano Kverkfjoll, at the northern margin of ...
openaire +1 more source
TEPHRAS, chronologie, archéologie
2001En 1998, à Brives-Charensac (Haute-Loire), une réunion internationale sous le patronage de la Commission on Tephrochronology de l'INQUA (E. JUVIGNE, Vice-Président) et de la Commission 31 de l'UISPP Hommes et volcans actifs durant la Préhistoire et la Protohistoire (J.P.
Juvigné, Etienne, Raynal, Jean-Paul
openaire +1 more source
1981
Tephra studies would benefit greatly from the development of simple, inexpensive, approximate-dating methods that would allow us to estimate the age of a tephra sample in the field office. Colleagues outside the discipline, whose main interest in tephra layers lie in the dates they represent, would benefit also.
openaire +1 more source
Tephra studies would benefit greatly from the development of simple, inexpensive, approximate-dating methods that would allow us to estimate the age of a tephra sample in the field office. Colleagues outside the discipline, whose main interest in tephra layers lie in the dates they represent, would benefit also.
openaire +1 more source