2 MSc positions in Precambrian paleo-redox geochemistry


Memorial University of Newfoundland (MUN), Supervised by: Dr. Michael Babechuk

Over a decade of research into the redox-sensitive element geochemistry of ancient sedimentary rocks has revolutionized our understanding of Earth's atmospheric oxygenation history. The Great Oxidation Event (GOE) is now viewed as a protracted interval of oxygen accumulation and fluctuations beginning near the Archean-Proterozoic boundary, preceded by transient 'whiffs' in Archean atmospheric oxygen perhaps by as much as 1.2 billion years. Nevertheless, there still remain conflicting lines of geochemical evidence from different paleo-redox proxies and between continental (e.g., paleosols) vs. marine (e.g., iron formation, carbonate) archives that leave an incomplete understanding of the different stages of atmospheric oxygenation.

Michael Babechuk is seeking 2 graduate students at the MSc level for the following projects under the broad theme of Precambrian redox evolution:

  1. Geochemical signatures of Neoarchean terrestrial weathering cycles - this study will focus on the mineralogy and geochemistry of the ca. 2.76 Ga Mt. Roe paleosol (Fortescue Group, Hamersley Basin, Western Australia). The earliest work on this paleo-weathering profile identified it as a "reduced" paleosol based on depletion of total Fe as Fe(II), but new work has suggested that an early oxidative weathering event is recorded in the paleosol with most Fe loss representing a subsequent, reducing diagenesis event. This project aims to further assess the relative timing and nature of separate alteration events with emphasis on Fe mobilization, and address other aspects of associated trace metal fluxes during chemical weathering in the Neoarchean.
  2. Terrestrial vs. hydrothermal solute sources in ca. 1.88 Ga iron formation - this study will focus on the mineralogy and geochemistry of the least-altered iron formation of the Labrador Trough (NL, Canada). After a main peak of iron formation (IF) deposition from ca. 2.7-2.4 Ga that waned as euxinic conditions expanded in tandem with the GOE, a return to ferruginous-dominated marine conditions is evident through a pulse of IF deposition ca. 1.84-1.88 Ga that includes the understudied Labrador Trough. The factors contributing to this return and subsequent demise of IF deposition remain debated (e.g., drop in atmospheric oxygen levels or widespread magmatism generating a marine reductant surplus). To further address this debate, multi-proxy geochemistry of chert and oxide minerals will be undertaken to unravel the fingerprint of solutes sourced from terrestrial oxidative weathering and any spatial/temporal changes in their flux relative to hydrothermally sourced solutes.

Applicants will have the opportunity to develop skills in in situ analysis (SEM, EMPA) at MUN, and high-precision trace element and stable metal isotope geochemical analysis abroad in Ireland, Germany, or both. Applicants should be: a) in excellent academic standing, eligible for internal MUN and external funding (e.g., NSERC PGS) support; b) have strong interests in pursuing academic research in trace element geochemistry, and; c) have existing experience with sedimentology, ICP-MS and clean lab chemistry, or a strong desire to develop such skills.

Interested applicants should email a statement of interest and CV to Dr. Michael Babechuk. Screening of applicants will continue until suitable candidates are found, but it is anticipated that candidates will start in September 2017 or January 2018. Official application to MUN requires original transcripts, 2 letters of recommendation, and proof of English proficiency (www.mun.ca/become/graduate/apply/). MUN currently pays MSc students a base salary of $18,989/year (assuming an offer of MUN Graduate Studies support and a teaching assistance position, which are granted competitively on the basis of academic standing) and up to a maximum of $27,500/year if supported by external funding. The tuition fees at MUN remain highly competitive at a national and international level (www.mun.ca/become/graduate/fees_funding/).

MUN is located in the vibrant and culturally fascinating seaside city of St. John's, Newfoundland & Labrador (www.stjohns.ca) that offers ample access to hiking, whale/iceberg watching, and live music.

Applications and inquiries via mun17041@earthworks-jobs.com

published: 19 April 2017     Please mention EARTHWORKS when responding to this advertisement.