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Titolo:
Icelandic pseudocraters as analogs to some volcanic cones on Mars
Autore:
Greeley, R; Fagents, SA;
Indirizzi:
Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA Arizona State Univ Tempe AZ USA 85287 niv, Dept Geol, Tempe, AZ 85287 USA
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
fascicolo: E9, volume: 106, anno: 2001,
pagine: 20527 - 20546
SICI:
0148-0227(20010925)106:E9<20527:IPAATS>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
GROUND ICE; HYDROVOLCANIC EXPLOSIONS; TERRESTRIAL ANALOGS; LAVA FLOWS; STABILITY; DISPERSAL; ERUPTIONS; RHEOLOGY; FIELD;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
60
Recensione:
Indirizzi per estratti:
Indirizzo: Greeley, R Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA Arizona State Univ Tempe AZ USA 85287 Sci, Tempe, AZ 85287 USA
Citazione:
R. Greeley e S.A. Fagents, "Icelandic pseudocraters as analogs to some volcanic cones on Mars", J GEO R-PLA, 106(E9), 2001, pp. 20527-20546

Abstract

Pseudocraters are rootless vents formed by the interaction of lava flows with surface or near-surface water. This interaction can produce mild explosions and the accumulation of scoria and spatter into small constructs. Pseudocraters in several localities in Iceland were examined in the field and compared to similar appearing features observed on Mars. The Icelandic pseudocrater cones in this study range in size from 6 to 70 m in diameter, have summit craters which range from 2 to 28 m in diameter (many cones lack craters entirely), and have flanks that are either concave-up or convex-up. Thesize and spacing of Icelandic pseudocraters might be a function of the availability of water, in which larger, closely spaced features result from efficient lava-water interaction, as suggested by the environments in which the features formed. Possible Martian pseudocrater cones in Amazonis Planitia range in diameter from 30 to 180 m and have craters 12 to 80 m in diameter. A numerical model for volcanic explosions was adapted to study the formation of pseudocraters under terrestrial and Martian conditions. The resultssuggest that explosions forming Martian cones require significantly less water (calculated masses are less by a factor of 4 to 16) than those formingIcelandic pseudocraters, despite their larger sizes. This is attributed tothe low gravity and atmospheric pressure in the Mars environment and is consistent with the likely lower abundance of water, which might be present as interstitial ice at shallow depths in the regolith. Locations of potential pseudocraters on Mars at latitudes as low as similar to8 degreesN, imply the presence of crustal ice stores at the time of their formation.

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Documento generato il 18/01/20 alle ore 22:25:48