Geochemistry of Paleoproterozoic Granular Iron Formations (East Arm of Great Slave Lake)

Regions: North Slave Region, South Slave Region

Tags: physical sciences, bedrock, sedimentary rocks, banded iron formation, mineral deposit

Principal Investigator: Pecoits, Ernesto (1)
Licence Number: 15348
Organization: University of Alberta
Licenced Year(s): 2013
Issued: Oct 11, 2013
Project Team: Ernesto Pecoits (Principal Investigator, University of Alberta), Kurt Konhauser (Research Supervisor, University of Alberta), Luke Ootes (Research Collaborator, Northwest Territories Geoscience Office), Andrey Bekker (Research Collaborator, University of Manitoba)

Objective(s): To delineate the source (continental, hydrothermal) of silica and iron in banded iron formation (BIF); to make inferences about the seawater from which these rocks were deposited in; and, to evaluate the implications for early life on Earth.

Project Description: By means of geochemical data on banded iron formation (BIF), and associated volcanic and sedimentary rocks the main objectives of this study are:

(1) to delineate the source (continental, hydrothermal) of silica and iron in BIF,
(2) to make inferences about the seawater from which these rocks are deposited in, and
(3) to evaluate the implications for early life on Earth.

This study will require bedrock investigation, the construction of a detailed geological map, collection of representative bedrock samples (samples are about half a fist size and are collected by use of a hand held hammer and samples are derived from a discrete location on the bedrock). The samples will be investigated, and will then be crushed and analyzed by petrographic (microscope), radiometric (isotope measurement), Scanning Electron Microscope (SEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), X-Ray diffraction (XRD), microprobe and stable isotopes (C, O, Si and Fe) analyses. These analyses can be completed at the University of Alberta. Special interest will be placed in bioessential, redox-sensitive trace elements and rare earth elements, which will serve to reveal several aspects regarding the source and oxygen availability in the ocean at this time and what role nutrient status of the oceans played, if any, relative to other factors in early life.

Future communication and guidance about other similar types of rocks in the East Arm would be invaluable. The research team will communicate results of the project at a forthcoming Yellowknife Geoscience Forum and provide information to future community outreach programs conducted by the NWT Geoscience Office. Direct questions by community members about the results of the project are welcome and encouraged and individuals or groups can communicate directly with L. Ootes at the NWT Geoscience Office anytime.

Depending upon results, they will be written into a scientific journal paper that is of the early Earth discipline (e.g. Precambrian Research). At the request of communities, a plane language overview of progress and/or results can be submitted as results from the study become available.


The fieldwork for this study will be conducted from October 9, 2013 to December 31, 2013.