Marjolaine Verret

Majorlaine at Jökulsárlón in Iceland during the winter

Contact

Phone: 04 463 5233 x 8619
Email:
Marjolaine.Verret@vuw.ac.nz
Office: CO523

Qualifications

BSc University of Ottawa (2015); MSc University of Ottawa (2017)
PhD Candidate in Permafrost Geochemistry

PhD thesis

Title

Origin of ground-ice and organic carbon in Miocene sediments, Friis Hills, Antarctica.

Supervisor

Supporting academics:

Project objectives and description

This project aims to understand the unique geochemical characteristics of the sediment cores retrieved during the 2016 Friis Hills Drilling Project. These cores provide an unprecedented record of Antarctic environmental changes from approximately 15 million years ago, which was the last time global climate averaged 3 – 5°C warmer than present.

Antarctic permafrost plays a special role in recording glacial history and past climate. Stable isotopic analyses are essential for understanding the origin and age of permafrost and ground ice in the Arctic, but Antarctic permafrost remains largely unstudied. Isotopic fractionations, which occur during phase changes (i.e. freezing, condensation, absorption), provide a unique signature preserved in permafrost. This signature is comparable to that of the meteoric water and can therefore be used to understand the origin and timing of its formation.

The abundance and origin of organic carbon also remain poorly understood in Antarctic paleo-environments. During the Miocene and possibly other warm periods, lakes occupied Friis Hills area. A significant proportion of the soil organic carbon has been produced and deposited in these paleo-lake environments. Soil 13Corg can be used as a tracer of the source of organic carbon and provide additional information on paleo-environments. The response of permafrost to past and future climate changes remains widely unexplored, especially in Antarctica, and could be further understood through the analysis of ground ice, its cryostructures and geochemical characteristics, along with a further understanding of its soil organic carbon and nitrogen content.

Friis Hills Core; Key Geochemical Questions

  • What paleoclimate signatures are possible from the ice and organics in the sediment?
  • What is the source of the ground ice?
    1. Was it the water of deposition;
    2. was it derived from rain at a later time, or
    3. was the ground ice precipitated from via diffusion of atmospheric vapour.
  • How did the productivity and geochemistry of the shallow lake sediments change over time?

Publications

Verret, M., Wang, Y., Bjornson, J., Lacelle, D. (2019). Hummocks in alpine tundra, northern British Columbia, Canada: Distribution, morphology and organic carbon composition. Arctic Science doi:10.1139/AS-2018-0021

Verret, M. (2017) Distribution and Growth of Earth Hummocks in the Chuck Creek Trail Valley, Northern British Columbia, Canada. Master’s Thesis, University of Ottawa, Department of Geography.

Verret, M. (2015) Comparison in the daily isotopic and conductivity variations between a glacial and a non-glacial watershed in the Kluane region. Undergraduate Research Thesis, University of Ottawa, Department of Geography.