Regions: Gwich'in Settlement Area, North Slave Region
Tags: physical sciences, geology, geochemistry, stratigraphy, petrology, banded iron formation
| Principal Investigator: | Mloszewski, Aleksandra M (2) |
| Licence Number: | 14979 |
| Organization: | Earth and Atmospheric Sciences, University of Alberta |
| Licensed Year(s): |
2011
2010
|
| Issued: | Nov 30, 2011 |
| Project Team: | Kurt Konhauser (Supervisor, University of Alberta), Ernesto Pecoits (Field Assistant - Post-Doctoral Student, University of Alberta) |
Objective(s): To undertake field and laboratory studies of Archean and Proterozoic Banded Iron Formation from the Central Slave Cover Group.
Project Description: The recent discovery of new occurrences of Neoarchan (2.8 Ga to 2.6 Ga) banded iron formations (BIF) in the Northwest Western Territories have opened an exceptional opportunity to study ocean chemistry. In this regard, the research group has been engaged by the Northwest Territories Geoscience Office (NTGO) to undertake field and laboratory studies of Archean and Proterozoic Banded Iron Formation from the Central Slave Cover Group. The fieldwork conducted as a result of this partnership will be an important contribution to the growing database of BIF composition throughout the Archean, and provides us with additional geochemical data to the sampling carried out last summer in the Nuvvuagittuq Greenstone Belt (northern Québec) (collected in July 2009). The preliminary exploration of these banded iron formation units last summer (August 2010) has provided the stratigraphic and initial petrographic and geochemical framework needed in order to conduct the necessary detailed geochemical sampling this year (2011). Sampling sites will include the ca. 2.62 Ma year old BIF at Point Lake, which are interbedded with greywacke-mudstone turbidites, the ca. 2850 Ma year old BIF (magnetite-chert type) in the Central Slave Cover Group ~30 km north of Yellowknife, and detailed sampling of BIF belonging to the Central Slave Cover Group at the NTGO core lab. This data will provide an unparalleled opportunity to address a fundamental question in geobiology, that being whether the trace metals available to microbes in the Archean ocean are still used in the metallo-enzymes of modern microbes? The metal contents will be apprised in some modern metallo-enzymes with advanced mass spectrometry techniques for protein identification and sequencing, in collaboration with Mak Saito (Woods Hole Oceanographic Institute). By comparing these results with the availability of trace metals in the early ocean, we will know which metabolic types were available to microbes throughout the Archean. This study is a unique opportunity to understand the evolution and ecology of Earth`s oldest ecosystem and may reveal important information about the cause(s) of the Great Oxidation Event (GOE). Like for the BIF from Northern Québec, a multifaceted approach will be taken to analysing the NWT BIF samples, involving petrographic analysis, bulk geochemical and mineral-phase geochemical analysis. Rocks will be cut and polished into thin sections for petrographic and fine-scale geochemical analysis. Bulk samples of the BIF will be cut and milled into powder for bulk geochemical analysis via x-ray fluorescence (XRF). Mineral phase geochemistry will be analysed using an electron microprobe (EMP) and laser inductively coupled mass spectrometry (laser ICP-MS). To fully analyze all the samples collected in the NWT and to do protein identification and sequencing analyses on some modern metallo-enzymes, the methods described above are anticipated to take between 18 and 24 months (aiming to be completed in August 2012). A manuscript based on BIF from Northern Québec is currently underway (Mloszewska A.M, Pecoits E, Mojzsis S.J, Konhauser K.O. Petrography and Geochemistry chemical sediments from the recently-discovered Nuvvuagittuq Greenstone Belt (Northern Québec) and implications for the composition of Earth`s earliest oceans. The geochemical information resulting from this work will be an important asset in our growing geochemical database for BIF through time, and offers us the unparalleled opportunity to assess the evolution of oceanwater composition through the Archean. The funds available through the CCI and NSTP Research Grants Programs would be used to offset some of the high travel and logistical costs associated with working in NWT (Canada) this year. It is important to find opportunities to inform the local northern community about this research project. In this regard, reports about the interpretation of the dataset and analyses will be timely presented in order to maximize the knowledge of this community about the goals and results of the research. In addition, workshop attendance in local community learning centers will provide the opportunity to interact with the locals 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. Furthermore, the researchers are interested in hiring an interested person from the community to be part of the field work team, as the acquisition of local knowledge on hand would greatly help. This project will serve to help to better understand the geological process related to the formation of banded iron formations and their economic potential, but will also broaden our understanding of the period leading up to the oxygenation of our atmosphere, ca. 2.4 billion years ago. 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.
