Environmental Engineering Reference
In-Depth Information
in the lava stratigraphy, and the relationships between speci
c pulses of LIP
eruption/emplacement and mass extinctions/biotic crises.
We propose that the active
c rocks in LIPs
for tectonic applications (e.g. Ernst
et al
.,
2013
) can, in some cases be taken to
higher levels of precision and accuracy by: (1) utilizing a variety of U-bearing
accessory minerals in addition to zircon, including perovskite, baddelyite and
zirconolite to better understand the age, duration, and tempo of LIP magmatism;
and (2) integrating the U
-
Pb and
40
Ar
-
field of U
-
Pb geochronology of ma
39
Ar geochronometers. Additionally, it is
clear that to fully understand the origin and signi
cance of LIPs in Earth history as
well as the links between LIPs and global environmental perturbation, multiple,
stratigraphically well-constrained dates on ma
c rocks are essential. This will
allow detailed testing of the environmental effects of large eruptions with the
emerging highly resolved records of extinction intervals. The next level of inquiry
must involve testing model predictions for collapse of ecosystems based on the
relative timing between eruption, the relative timing of increased CO
2
levels in the
oceans and atmosphere, variations in pH, and anoxia, for example. Ideally this
will involve integration of paleomagnetic data (including secular variations),
astrochronology, and
40
Ar
-
39
Ar and U
-
Pb geochronology. Doing so will put age
models with millennial-scale resolution for the last 542 Myr within our grasp.
References
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'
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Pb dating of coexisting baddeleyite, zircon, and
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51.
Baksi, A. K. (2014) The Deccan Trap Cretaceous
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Ar/
39
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Ar/
39
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Baski, A. K. (2013)
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40
Ar,
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