[meteorite-list] article of interest in "Nature"

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Fri, 27 Apr 2007 11:57:58 -0400
Message-ID: <000f01c788e4$d442ff30$6402a8c0_at_Dell>

Thank you Sterling for accessing the abstract and especially thanks for the
"translation", which is what I surmised.
Jerry Flaherty
----- Original Message -----
From: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
To: "Gerald Flaherty" <grf2 at verizon.net>;
<Meteorite-list at meteoritecentral.com>
Sent: Friday, April 27, 2007 3:00 AM
Subject: Re: [meteorite-list] article of interest in "Nature"

> Hi, Jerry, List,
> Here's the abstract:
> "The abundance of chlorine in the Earth
> is highly depleted relative to carbonaceous
> chondrites and solar abundances. Knowledge
> of the Cl concentrations and distribution on
> Earth is essential for understanding the origin
> of these depletions. Large differences in the
> stable chlorine isotope ratios of meteoritic,
> mantle and crustal materials have been used
> as evidence for distinct reservoirs in the solar
> nebula and to calculate the relative proportions
> of Cl in the mantle and crust. Here we show,
> using a new analytical procedure, that these
> large isotopic differences do not exist, and
> that carbonaceous chondrites, mantle and
> crust all have the same 37Cl/35Cl ratios.
> There is no evidence for multiple nebular
> reservoirs with distinct isotopic compositions.
> That is to say, there is no evidence to support
> addition to the crustal/atmospheric reservoir
> of late material of cometary origin. We have
> further analyzed crustal sediments from early
> Archean to Recent and find no isotopic
> variations with age, demonstrating that the
> mantle and crust have always had the same
> d37Cl value. The similarity of mantle, crust
> and carbonaceous chondrites establishes
> that there was no isotopic fractionation
> during differentiation of the Earth and no
> late Cl-bearing volatile additions to the crustal
> veneer with unique isotopic composition."
> Translation:
> "Despite the fact that there are big differences
> in the amount of chlorine in the Earth's crust and
> mantle (on the one hand) and carbonacious chondrites
> and the Sun (on the other hand), we think the ratio
> of stable isotopes everywhere in the solar system
> is the same (even though other folks get different
> measurements), and that proves that everything
> came out of the same cookpot, 'cause our method
> of measuring is better than theirs."
> Specifically, they want to shoot down the idea
> that there was a last-minute accretion of comets and
> such on the surface of the Earth that would explain
> why crust is so different than mantle. Presumably,
> this would also shoot down the idea that the Earth's
> water was brought to it largely by comets.
> The quarrel we call "knowledge" goes on...
> Sterling
> -------------------------------------------------------------
> ----- Original Message -----
> From: "Gerald Flaherty" <grf2 at verizon.net>
> To: <Meteorite-list at meteoritecentral.com>
> Sent: Thursday, April 26, 2007 9:33 PM
> Subject: [meteorite-list] article of interest in "Nature"
> "Chlorine isotope homogeneity of the mantle, crust and carbonaceous
> chondrites
> Z. D. Sharp et al.
> Nature
> doi: 10.1038/nature05748
> First Paragraph | Full Text | PDF"
> I only get these text messages with no links but if anyone who has access
> to
> Nature cares to explore and "report" ?
> Jerry Flaherty
> ______________________________________________
> Meteorite-list mailing list
> Meteorite-list at meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list
Received on Fri 27 Apr 2007 11:57:58 AM PDT

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