[meteorite-list] Brimstone Pickled Permian

From: colin wade <ceweed_at_meteoritecentral.com>
Date: Thu Apr 22 09:49:01 2004
Message-ID: <000001c140b1$d66ad840$02000003_at_colinwad>

Hi folks

>From a Christian with Muslim , Sihk , Bhuddist, Hundu & appologies to those
not mentionnned ,collegues , curently with family in the Middle East ,
thanks Ron for keeping the flow gowing.
i get the impression that the cycle of heavy meteoritic impact is cyclic ,
galactic spirals et al , does the new info from your posting increase our
handle on the next visitations ?
curious
God Bless
 Colin

----- Original Message -----
From: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, September 18, 2001 8:34 PM
Subject: [meteorite-list] Brimstone Pickled Permian


>
>
> http://www.nature.com/nsu/010920/010920-6.html
>
> Brimstone pickled Permian
>
> Two hundred million years before the dinosaurs' demise another meteorite
> impact may have devastated life on Earth.
>
> PHILIP BALL
> Nature Science Update
> September 18, 2001
>
> Two hundred and fifty million years ago, life on Earth nearly ceased. A
> giant meteorite, six times larger than the one that did away with the
> dinosaurs almost two hundred million years later, may have caused the
> massive extinction at the end of the Permian period, researchers now
> suggest.
>
> Kunio Kaiho of Tohoku University, Japan, and his colleagues have found
> evidence in southern China that a massive impact converted huge amounts of
> solid sulphur into sulphur-rich gases[1].
>
> The released sulphur could have consumed 20-40 per cent of the
atmosphere's
> oxygen, and generated enough acid rain to raise the acidity of the ocean's
> surface waters temporarily to that of lemon juice. Ocean life would have
> been pickled.
>
> The fossil record shows that 95 per cent of all species disappeared in the
> mass extinction that ended the Permian period. The event was more dramatic
> even than the perishing of 70 per cent of species - including the
dinosaurs
> - at the boundary of the Cretaceous and Tertiary periods 65 million years
> ago. The Cretaceous-Tertiary extinction is generally blamed on a meteorite
> impact in what is now the Gulf of Mexico.
>
> For many years, the Permian extinction was thought to have been more
> gradual, perhaps resulting from slow environmental changes. The formation
of
> vast plains of volcanic rock called the Siberian Traps, some researchers
> suggest, released gases that either boiled or froze the Earth, through the
> greenhouse effect or the reflection of sunlight from dust-like particles.
>
> Other evidence points to the Permian extinction having been abrupt,
> happening within 8,000-100,000 years - a timescale that implicates an
> impacting comet or asteroid. This idea is supported by the discovery
earlier
> this year[2] of fullerenes, cage-like carbon molecules, in sediments from
the
> end of the Permian. The molecules contained atoms of rare gases such as
> helium, implying that they came from a meteorite.
>
> Now Kaiho's team has found sulphate in end-Permian limestone, marl and
shale
> rocks formed from shallow sea-floor sediments. The rocks also have a
> nickel-rich layer, which could have been carried by an impacting
meteorite.
> Moreover, in the nickel-rich layer, the researchers detect a sudden change
> in the relative amounts of different sulphur isotopes (whose atoms have
> slightly different masses).
>
> If a giant meteorite impact vaporized a large area of sulphur-containing
> rock where it struck the seabed, it would probably have ejected the
lighter
> of sulphur's two common natural isotopes into the air, changing the
isotope
> ratio of the remaining rocks.
>
> From the size of isotope ratio shift, Kaiho's group estimates that the
> meteorite could have been up to 60 kilometres across. The
> Cretaceous-Tertiary meteorite was probably less than 10 km across.
>
> References
>
> 1. Kaiho, K. et al. End-Permian catastrophe by a bolide impact: evidence
> of a gigantic release of sulfur from the mantle. Geology, 29, 815 -
> 818, (2001).
> 2. Becker, L., Poreda, R. J., Hunt, A. G., Bunch, T. E. 7 Rampino, M.
> Impact event at the Permian-Triassic boundary: evidence from
> extraterrestrial noble gases in fullerenes. Science, 291, 1530 -
1533,
> (2001).
>
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Received on Tue 18 Sep 2001 03:28:24 PM PDT