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Titolo:
Stable methane hydrate above 2 GPa and the source of Titan's atmospheric methane
Autore:
Loveday, JS; Nelmes, RJ; Guthrie, M; Belmonte, SA; Allan, DR; Klug, DD; Tse, JS; Handa, YP;
Indirizzi:
Univ Edinburgh, Dept Phys & Astron, Edinburgh EH9 3JZ, Midlothian, Scotland Univ Edinburgh Edinburgh Midlothian Scotland EH9 3JZ Midlothian, Scotland Natl Res Council Canada, Steacie Inst Mol Sci, Ottawa, ON K1A 0R6, Canada Natl Res Council Canada Ottawa ON Canada K1A 0R6 tawa, ON K1A 0R6, Canada
Titolo Testata:
NATURE
fascicolo: 6829, volume: 410, anno: 2001,
pagine: 661 - 663
SICI:
0028-0836(20010405)410:6829<661:SMHA2G>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
HIGH-PRESSURE; CLATHRATE; DIFFRACTION; SYSTEM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Loveday, JS Univ Edinburgh, Dept Phys & Astron, Mayfield Rd, Edinburgh EH93JZ, Midlothian, Scotland Univ Edinburgh Mayfield Rd Edinburgh Midlothian Scotland EH9 3JZ
Citazione:
J.S. Loveday et al., "Stable methane hydrate above 2 GPa and the source of Titan's atmospheric methane", NATURE, 410(6829), 2001, pp. 661-663

Abstract

Methane hydrate is thought to have been the dominant methane-containing phase in the nebula from which Saturn, Uranus, Neptune and their major moons formed(1). It accordingly plays an important role in formation models of Titan, Saturn's largest moon. Current understanding(1,2) assumes that methanehydrate dissociates into ice and free methane in the pressure range 1-2 GPa (10-20 kbar), consistent with some theoretical(3) and experimental(4,5) studies. But such pressure-induced dissociation would have led to the early loss of methane from Titan's interior to its atmosphere, where it would rapidly have been destroyed by photochemical processes(6,7). This is difficultto reconcile with the observed presence of significant amounts of methane in Titan's present atmosphere. Here we report neutron and synchrotron X-raydiffraction studies that determine the thermodynamic behaviour of methane hydrate at pressures up to 10 GPa. We rnd structural transitions at about 1and 2 GPa to new hydrate phases which remain stable to at least 10 GPa. This implies that the methane in the primordial core of Titan remained in stable hydrate phases throughout differentiation, eventually forming a layer of methane clathrate approximately 100 km thick within the ice mantle. This layer is a plausible source for the continuing replenishment of Titan's atmospheric methane.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 20:35:51