Environmental Engineering Reference
In-Depth Information
12.8 Summary
Volatile generation in the sub-volcanic part of LIPs occurs during sill intrusions
into the sedimentary strata of volcanic basins. The style of emplacement
(deep-seated intrusion versus eruption) and type of sedimentary cover (coals,
shale, carbonates, evaporites) determine the amount and the composition of
generated gases.
Thermogenic gases release mainly through pipes,
fissures and small vent struc-
tures, offering a fast and ef
cient mechanism for inducing environmental change
or even mass extinction.
More work is needed to explore the halocarbon degassing hypothesis as
presented here. New quantitative experiments on rock salt must be conducted
to improve composition and volume estimates of pipe degassing scenarios for
eastern Siberia.
The role of gas release from cooling magma and from recrystallizing country
rock following magma
sediment interaction and sediment assimilation must be
investigated to improve atmospheric gas release estimates.
-
We suggest that the main reason why the Siberian Traps is associated with a major
extinction event is the chemical composition of the heated sedimentary rocks.
A key fact is that one of the world
'
is biggest salt deposits was intruded by 1,200
C
igneous sills in eastern Siberia at the same time as the end-Permian extinction.
Acknowledgements
This study was supported by a Centre of Excellence grant to CEED and by a
grant to H. Svensen, both from the Norwegian Research Council. We thank TGS
for permission to use seismic data, and Yuri Podladchikov, Seth Burgess, Dougal
Jerram, Stephane Polteau and Clement Ganino for the company and scienti
c
input during
eldworkinSiberia.
References
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ma
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