The Open UniversitySkip to content
 

Oxygen isotopes and the early solar system

Franchi, I.A.; Baker, L.; Bridges, J.C.; Wright, I.P. and Pillinger, C.T. (2001). Oxygen isotopes and the early solar system. Philosophical transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 359(1787) pp. 2019–2035.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1098/rsta.2001.0894
Google Scholar: Look up in Google Scholar

Abstract

Meteorites preserve a wide range of oxygen isotopic signatures from the time of the Solar System's formation. Most of these rocks record complex histories, each phase of which has the potential for overwriting initial oxygen signatures. The unequilibrated ordinary chondrites reveal evidence of hydrothermal alteration through isotopic disequilibrium within chondrules and in secondary magnetites, which we can now constrain to temperatures of 140-180°C. The effects of this alteration are progressively obliterated by later thermal metamorphism. Further heating leads to melting (shown in achondritic meteorites), producing well-defined mass-fractionation lines using high-precision analyses. The oxygen from low-temperature minerals in carbonaceous chondrites reveals high levels of isotopic uniformity, suggesting that the aqueous alteration occurred under open-system conditions. The initial isotopic composition of the water from the ordinary chondrites is quite distinct from that in the carbonaceous chondrites, but both fall on a single line of slope 1.0, as do the initial anhydrous silicate compositions. This is taken to show that a process generating a mass-independent fractionation was responsible for most of the oxygen-isotopic variation seen in meteorites. Subsequent aqueous alteration of the meteorite parent bodies involving these components is then capable of producing the full observed variation.

Item Type: Journal Article
ISSN: 1364-503X
Keywords: Meteorites; Oxygen Isotopes; Hydrothermal Alteration; Chondrites; Mass-Independent Fractionation
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 3147
Depositing User: Users 6044 not found.
Date Deposited: 06 Jul 2006
Last Modified: 02 Dec 2010 19:49
URI: http://oro.open.ac.uk/id/eprint/3147
Share this page:

Altmetrics

Scopus Citations

Actions (login may be required)

View Item
Report issue / request change

Policies | Disclaimer

© The Open University   + 44 (0)870 333 4340   general-enquiries@open.ac.uk