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Pairing geochemistry and sedimentology: an evaluation of Alberta’s earliest Triassic deposits and the proxies used to study them
- Author / Creator
- Playter, Tiffany L.
The end-Permian mass extinction, 250 million years ago, was the largest in Earth’s history,
with estimates of faunal species loss up to ~90%. Western Canada plays host to deposits
spanning the Permian-Triassic boundary (the Belloy and Montney Formations) allowing for
the paleoenvironmental conditions surrounding post-extinction recovery to be evaluated.
Utilizing both geochemical methods, such as trace element proxies and carbon isotopes, as
well as sedimentology, this thesis has four aims: 1) evaluate the main mechanism facilitating
the existence of marine refugia post-extinction, 2) determine if Siberian Trap volcanism was
a factor in the delayed faunal recovery in the Early Triassic, 3) ascertain if the geochemical
signatures of events within the Early Triassic can be used to correlate deposits across the
basin and 4) examine the reliability of the geochemical proxies used to ascertain
paleoenvironmental conditions. This thesis demonstrates that, following the end-Permian
mass extinction, biotic recovery was facilitated by the monsoon cycle which produced
coastal upwelling via Ekman transport and nutrient-rich runoff from increased rainfall.
Additionally demonstrated, through the detailed evaluation of trace element proxies, is the
subsequent eruption of the Siberian Traps at the end of the Smithian, which resulted in a
temperature increase of 10°C, enhanced continental weathering, and a 0.55 unit decrease in
seawater pH which resulted in ocean acidification and anoxia. These signatures are
correlated, using chemostratigraphy, across the Western Canada Sedimentary Basin,
dividing Early Triassic deposits into 13 chemostratigraphic packages. Lastly, by examining
the interaction of cyanobacteria and clay during flocculation, this thesis suggests that the
geochemical signatures of fine-grained deposits, such as the Triassic Montney Formation,
can be altered by biological activity within the water column, in addition to seawater
composition and redox state.
- Graduation date
- Spring 2020
- Type of Item
- Doctor of Philosophy
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.