NWT RESEARCH DATABASE

Regions: Gwich'in Settlement Area, North Slave Region

Tags: physical sciences, geology, paleontology, banded iron formation

Objective(s): To better resolve the climatic and oceanic chemical conditions that ultimately led to the origins of animal life and the so-called ‘Cambrian explosion’ by focusing on the exceptionally well-preserved ancient banded iron formations from the Rapitan Group (NWT, Canada) and the overlying carbonate units.

Project Description: Objectives The researcher intends to better resolve the climatic and oceanic chemical conditions that ultimately led to the origins of animal life and the so-called ‘Cambrian explosion’ by focusing on the exceptionally well-preserved ancient banded iron formations from the Rapitan Group (NWT, Canada) and the overlying carbonate units. Specifically, detailed chemical and isotopic analyses of these rocks will help in the understanding of: (1) the role of deep-sea oxygenation; (2) bioessential major and trace element availability; (4) effects on the biosphere imposed by severe climatic fluctuations; (5) establishing the precise age of deposition; and (6) correlation of the succession with other sequences and major paleoclimatic events worldwide (ice-house and green-house conditions). The initial stage of this multifaceted work requires a strong field based research, including mapping, construction of detailed cross-sections and collection of samples. This will provide a precise idea of the geological setting and palaeoenvironmental conditions at the time of deposition. Analytical methods to be used in this multifaceted study include petrographic, micropalaeontologic, radiometric, Scanning Electron Microscope (SEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), X-Ray diffraction (XRD), microprobe and stable isotopes (C, O, and Fe) analyses at the University of Alberta. The researcher will particularly focus on bioessential, redox-sensitive trace elements and rare earth elements, which will serve to reveal several aspects regarding oxygen availability in the ocean at this time, the paleo-nutrient status of the oceans, and potentially the conditions that the rise of animals. Direct dating, using U-Pb and Ar-Ar methods, will provide a geochronological framework necessary for understanding the critical geological events recorded in these sections. The researcher will seek out opportunities to inform the community about the research project. In this regard, reports about dataset and analysis interpretation will be timely presented in order to maximize the community knowledge about the goals and results. In addition, attendance to workshops in local community learning centers will provide us the opportunity to interact with the people and give educational training. All purchases/expenses related to fieldwork will be done locally. Consultation with the community will help to identify individuals and local businesses who can provide travel and accommodation support. This project will contribute in the field of the basic geology; however, the understanding of the process related to the units to be studied would contribute to the understanding of their economic potential. Poster and oral presentations at the Yellowknife Geoscience Forum, updates on research findings disseminated through NWT Geoscience Office Outreach geologists, and published results provided to Aurora Research Institute.