Siberian flood basalts and the end-Permian environmental crisis

Paul bristolia at yahoo.com
Mon Dec 29 00:58:40 EST 2008

In press in the "Earth and Planetary Science Letters" is:

Svensen, H., S. Planke, A. G. Polozov, N. Schmidbauer, F. Corfu,
Y. Y. Podladchikov, and B. Jamtveit, in press, Siberian gas
venting and the end-Permian environmental crisis. Earth and
Planetary Science Letters.

The PDF file for this paper can be found at:

http://folk.uio.no/yuripo/papers/svensen_epsl_09.pdf

They concluded that that heating of Tunguska Basin sediments by
the ascending magma of the Siberian Traps Large Igneous Province
was capable of playing a key role in end-Permian environmental
crisis. They argue that the cooking of organic-rich shales and
petroleum-bearing evaporites around sill intrusions produced
sufficient volumes of greenhouse gases and halocarbons to cause
warming and atmospheric ozone depletion on a global scale. They
estimated that the metamorphism of organic matter and petroleum
generated over 100,000 Gigatons of CO2 that were released through
enormous pipe structures associated with kilometre-sized craters.
They also argue from laboratory experiments that cooking of
petroleum-bearing rock salt at high temperatures by the magmas
generated huge quantities of methyl chloride and methyl bromide
that have resulted not only in global warming but also global ozone
depletion.

PDF files of ther papers of Dr Henrik Svensen can be found at:

http://folk.uio.no/hensven/publications.htm

The source of PDF file of related papers where noted in
"[meteorite-list] Online PDF files about Permian-Triassic
extinction" at;

http://six.pairlist.net/pipermail/meteorite-list/2008-December/048424.html

Note: I am only summarizing what the above paper states. As
result, this post reflect only the opinions of the authors
of the above paper and **not** my own opinions on this subject.
Thus, any disagreements should directed to the paper and it
authors and **not** me. Furthermore I feel no obligation to
defend their conclusions as I am still in the process of
evaluating the arguments made in this paper.

Yours,

Paul H.

Coal Methane Contributed Late Permian Extinctions ????

Paul bristolia at yahoo.com
Fri Dec 21 16:23:22 EST 2007

Dear friends,

There is an interesting paper about how coal methane
might have contributed to Late Permian extinctions.

It is:

Retallack, G. J., and A. H. Jahren. 2007, Methane Release
from Igneous Intrusion of Coal during Late Permian
Extinction Events. The Journal of Geology. vol. 116, pp. 1–20

http://www.journals.uchicago.edu/doi/abs/10.1086/524120

In part the abstract read:

“Unusually large and locally variable carbon isotope excursions
coincident with mass extinctions at the end of the Permian
Period (253 Ma) and Guadalupian Epoch (260 Ma) can be
attributed to methane outbursts to the atmosphere. .... On
paleogeographic maps, the most marked carbon isotope
excursions form linear arrays back to plausible methane
sources: end-Permian Siberian Traps and Longwood-Bluff
intrusions of New Zealand and end-Guadalupian Emeishan
Traps of China. Intrusion of coal seams by feeder dikes to
flood basalts could create successive thermogenic methane
outbursts of the observed timing and magnitude, ...
Methane released by fracturing and heating of coal during
intrusion of large igneous provinces may have been a
planetary hazard comparable with bolide impact.”

This paper concluded:

“Addition of the end-Guadalupian case to the better known
end-Permian, end-Triassic, and end-Cretaceous cases
makes coincidence less likely, and copious generation of
methane by intrusion of coals supplies ample killing power.
Like meteorite and comet impacts, thermogenic methane
outbursts may have been significant hazards to life on Earth.”

Yours,

Paul H.