[meteorite-list] re: tektite QUESTION

From: Marco Langbroek <marco.langbroek_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:28 2004
Message-ID: <005001c260ca$60a6ce40$67d986c2_at_latitude>

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
---

Received on Fri 20 Sep 2002 01:12:44 PM PDT