Environmental Engineering Reference
In-Depth Information
18.6 Summary
Our review of palaeoredox records from the Permian
-
Triassic transition suggests a
rapid shift from relatively well-ventilated late-Permian oceans to widespread
anoxic and euxinic conditions coincident with the extinction horizon. Redox
constraints from above the PTB provide evidence that anoxia recurred episodically
during Early Triassic time, particularly at the Smithian
-
Spathian boundary and
during the mid Spathian. Numerical models support the hypothesis that a rapid
increase in atmospheric
p
CO
2
and nutrient
fluxes could generate end-Permian
oceanic anoxia
-
euxinia, and the timing and volume of Siberian Traps eruption
provide a mechanism for the expansion of anoxia at the PTB. High-resolution
records using geochemical proxies that capture globally averaged marine redox
conditions hold particular promise for constraining the baseline redox state of
Permian oceans, the spatial and temporal distribution of Early Triassic anoxia,
and for testing the temporal correspondence between Siberian Traps volcanism and
Early Triassic variation in marine redox chemistry.
Acknowledgements
We thank L. Kump and K. Fristad for thoughtful reviews. This work was sup-
ported by the National Science Foundation (EAR-0807377 to J.L.P.).
References
Algeo, T. J., Henderson, C. M., Ellwood, B. B.
et al
. (2012). Evidence for a diachronous
late Permian marine crisis from the Canadian Arctic region.
Geological Society of
America Bulletin
, 124, 1424
1448.
Algeo, T. J., Hannigan, R., Rowe, H.
et al
. (2007). Sequencing events across the Permian
-
-
Triassic boundary, Guryul Ravine (Kashmir, India).
Palaeogeography, Palaeoclimat-
ology, Palaeoecology
, 252, 328
346.
Algeo, T. J., Shen, Y., Zhang, T.
et al
. (2008). Association of
-
34
S-depleted pyrite layers
13
C excursions at the Permian
with negative carbonate
Triassic boundary: evidence
δ
-
for upwelling of sul
dic deep-ocean water masses.
Geochemistry, Geophysics, Geo-
10.
Algeo, T. J., Hinnov, L., Moser, J.
et al
. (2010). Changes in productivity and redox
conditions in the Panthalassic Ocean during the latest Permian.
Geology
, 38,187
systems
, 9,1
-
190.
Alibo, D. S. and Nozaki, Y. (1999). Rare earth elements in seawater: particle association,
shale-normalization, and Ce oxidation.
Geochimica et Cosmochimica Acta
, 63,
363
-
372.
Archer, D., Kheshgi, H. and Maier-Reimer, E. (1997). Multiple timescales for neutralization
of fossil fuel CO
2
.
Geophysical Research Letters
, 24,405
-
408.
Beatty, T. W., Zonneveld, J. P. and Henderson, C. M. (2008). Anomalously diverse Early
Triassic ichnofossil assemblages in northwest Pangea: a case for a shallow-marine
habitable zone.
Geology
, 36, 771
-
774.
Bond, D. P. G. and Wignall, P. B. (2010). Pyrite framboid study of marine Permian
-
Triassic
boundary sections: a complex anoxic event and its relationship to contemporaneous
mass extinction.
Geological Society of America Bulletin
, 122,1265
-
1279.
-
