[meteorite-list] Re: tektite QUESTION

From: Michael L Blood <mlblood_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:29 2004
Message-ID: <B9B0DB5A.F8D%mlblood_at_cox.net>

Thanks to Paul, Bernd, Bruce, Marco (and many others
too numerous to mention),
    Got it now.
    Thanks, Michael
("Consensus" is 600K to 800K, with 700K to 800K the most common, depending
on a variety of "sources")

on 9/20/02 10:12 AM, Marco Langbroek at marco.langbroek_at_wanadoo.nl wrote:

> Hi Michael,
>
> The australasian tektite strewnfield formed around 0.8 million years ago
> (the 0.6- 0.77 million year ages sometimes found in the older literature
> need to be updated a bit). By far the most accurate 'relative' age estimate
> comes from comparing the stratigraphic position of microtektites from this
> strewnfield in deep-sea sediment cores with the paleo-magnetostratigraphy of
> those cores. The position of the Australasian microtektite layer in ODP
> cores 767 and 769 near the Phillipines (Schneider et al. 1992) and MD972142
> in the South China Sea and MD972143 in the West Philippine Sea (Lee and Wei
> 2000) point out that the strewnfield formed an estimated 12 000 to 15 000
> years before an important polarity change in the earth magentic field, the
> so called Brunhes-Matuyama boundary (the tektites are in the upper part of
> Oxygen Isotope Stage 20).
> This Brunhes-Matuyama polarity change has been dated to approximately 783
> 000 years ago according to the latest Ar-Ar dates.
>
> Marco Langbroek
>
> refs:
> 1) Lee M. and Wei K., 2000: Australasian microtektites in the South China
> Sea and the West Philippine Sea: Implications for age, size, and location of
> the impact crater. Meteoritics and Planetary Science 35, 1151-1155.
> 2) Schneider D.A., Kent D.V. and Mello G.A., 1992: A detailed chronology of
> the Australasian impact event, the Brunhes-Matuyama geomagnetic polarity
> reversal, and global climate change. Earth Planet. Sci. Let. 111, 395-405.
>
>
> ---------
> Message: 10
> Date: Thu, 19 Sep 2002 16:22:57 -0700
> From: Michael L Blood <mlblood_at_cox.net>
> To: <meteorite-list_at_meteoritecentral.com>
> Subject: [meteorite-list] Tektite QUESTION
>
> Hi All,
> I am sure I have it in more than one text SOMEWHERE, but can anyone
> tell me quick short the estimated age of the Austro-asian strewn field
> Tektites?
> RSVP
> Thanks, Michael
>
>
>
>
>
> ---
> Marco Langbroek e-mail: marco.langbroek_at_wanadoo.nl
> Diefsteeg 1
> NL-2311 TS Leiden
> the Netherlands
> http://home.wanadoo.nl/marco.langbroek/
>
>
> "What seest thou else
> In the dark backward and abysm of time?"
>
> William Shakespeare: The Tempest act I scene 2
> ---
>
>
>
>

I don't give a damn for a man that can only spell a word one way.
   Mark Twain

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Received on Fri 20 Sep 2002 05:04:10 PM PDT