524 research outputs found
Recommended from our members
Solar noble gases in Vigarano bulk minerals β First results of the new 'BENGEL' in-vacuo etching facility
Extract from introduction: Regolith breccias are breccias that contain solar-gas-bearing grains [1,2]. It is generally accepted that the exposure to the solar wind took place rather recently on the surface of a parent body. However, it appears possible that grains were exposed early (or obtained their solar gas load by other mechanisms) prior to accretion. Some of the solar gases in chondrites may indeed be 'primordial' [3,4]. In the CI chondrite Orgueil, the presence of solar gases is restricted to magnetite, whereas the silicates appear solar-gas-free [3]. This is difficult to reconcile in a planetary environment. The observation that solar-like gases in the unbrecciated E chondrite St. Mark's were released only upon severe etching provides further evidence for the presence of primordial solar gas [5]
Recommended from our members
Plutonium-Xenon systematics of Angrites
Introduction: Angrites are igneous meteorites that crystallized very early in the solar system, ~10 Ma after CAIs, as also implied by the presence of now extinct short-lived radionuclides such as 53Mn, 146Sm and 244Pu [1]. Fission Xe was used to calculate 244Pu-136Xeretention ages of eucrites, relative to that of Angra dos Reis (AdoR) [2]. AdoR has an absolute Pb-Pb age of 4557.8 Ma [see 1 for ref.]. Most eucrites, being as old as angrites, experienced various parent body processes leading to ages ranging from ~20 Ma before, to ~100 Ma after AdoR [2]. Angrites, however, remained largely unaltered after differentiation. Here, we examine whether Xe isotopic characteristics
allow determining an age sequence for angrites
Recommended from our members
Phase Q - A carrier for subsolar noble gases
We discuss noble gases in the E-chondrite St. Mark's indicating that the subsolar component does not exclusively reside in enstatite. Element and isotope abundances including He are presented. Fractionation probably took place prior to incorporation
Recommended from our members
Subsolar noble gases in an acid-resistant residue of the EH5 chondrite St Mark's
Extract from the introduction: Enstatite chondrites have remarkable properties: they were formed in a reducing environment, they are putatively similar to precursor material of Earth, Venus, or Mercury, have a terrestrial oxygen isotopic composition and an uncommon noble gas signature [1-5]. Trapped noble gases in Echondrites are intermediate between solar and chondritic composition and consist of two components: Subsolar, enriched in Ar and Kr relative to Xe and Q-gas, possibly residing in enstatite, micro-vesicles or graphite within enstatite [6,7] and Q-gases [5,8]
Recommended from our members
On line etching of bulk EH5 St. Mark's β Radiogenic and subsolar noble gases
Introduction: On line etching is very useful to analyse noble gas components such as 'Q' or the solar wind [1, 2]. A bulk meteorite sample, however, has never been analysed by on line etching in order to characterise its complete noble gas inventory
Recommended from our members
Ancient volcanic xenon in single glass grains from the D'Orbigny angrite
We present high-sensitivity xenon data for single glass grains from the D'Orbigny angrite. These grains contain the first sample of volcanic gas from a planetary body other than the Earth and excess Xe-129 detected for the first time in angrites
Recommended from our members
The pre-atmospheric size of Martian meteorites
The pre-atmospheric size of martian meteorites was calculated based on 80Kr produced by epithermal secondary cosmic-ray produced neutrons of 30-300 eV energy. For seven meteorites we obtained minimum radii of 22-27 cm, corresponding to 150-270 kg
Recommended from our members
Solar noble gases in the Angrite parent body β Evidence from volcanic volatiles trapped in D'Orbigny glass
We compare the noble gases in D'Orbigny glass and bulk. The glass was formed after the bulk silicates and contains interior solar noble gases that may originate from early volcanic activity on the angrite parent body, trapped upon fast cooling
- β¦