Xenon fractionation in porous planetesimals

Kevin Zahnle, James B. Pollack, James Kasting

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

The distinctively fractionated Xe on Mars and Earth may have its root in a common source from which both planets accreted. We begin with Ozima and Nakazawa's hypothesis that terrestrial Xe fractionation was caused by gravitational separation of adsorbed solar nebular gases inside large porous planetesimals. We point out that Xe would have been trapped as the planetesimal grew and pores were squeezed shut by lithostatic pressure. We show that enough fractionated Xe to supply the Earth could have been trapped this way. The degree of fractionation is controlled by the lithostatic pressure at the pore-closing front and so would have been roughly the same for all large planetesimals. The predicted degree of fractionation agrees well with that preserved in terrestrial and martian Xe. Relative to Xe, this source is strongly depleted in other noble gases. In contrast to the original Ozima and Nakazawa hypothesis, our hypothesis predicts the observed fractionation, and it allows planetary accretion to occur after the dissipation of the solar nebula. The required planetesimals are large, representing a class of object now extinct in the solar system.

Original languageEnglish (US)
Pages (from-to)2577-2586
Number of pages10
JournalGeochimica et Cosmochimica Acta
Volume54
Issue number9
DOIs
StatePublished - Jan 1 1990

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'Xenon fractionation in porous planetesimals'. Together they form a unique fingerprint.

  • Cite this