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.

• Subjects / Keywords

  • Triassic
  • chemostratigraphy
  • mass extinction
  • end-Permian
  • western canada sedimentary basin
  • Montney

• Graduation date

  Spring 2020

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-175s-1t98

• License

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