Date of Award
2007
Degree Type
Thesis
Degree Name
Master of Science
Program
Geology
Supervisor
Dr. N. Duke
Abstract
The Kipalu Iron Formation occurs within the Paleoproterozoic Belcher Group, deposited on the western Ungava margin of the Superior Province. The iron formation terminates shallow marine sedimentation and signals the onset of deep marine foreland basin deposition. It is intruded by 1.95 Ga subvolcanic gabbro sills and therefore was deposited late in the history of the Great Oxidation Event. The iron formation is immediately underlain by pink to white orthoquartzite and capped by black graphitic and pyritic argillite. Internally it is primarily composed of silicate facies argillite interlayered with cherry red jasper bands. Marine transgression over the shelf-shoreline environment gave rise to granular textured argillite while ooidrich chert signifies regressive events leading to subareal conditions and dehydration. Micro-structures in the hematitic chert suggest biogenic involvement in primary iron precipitation. Coarser euhedral magnetite and the occurrence offibrous riebeckite in the western exposures are a result oflow grade metamorphism. The Kipalu Iron Formation has total Fe2O3 contents in excess of 65% in oxide rich argillite but averages below about 30%. The Kipalu is quite free oftrace metals but contains upwards of2-5% MnO in carbonate-rich argillite. The LREE enrichment and elevated Ba suggest an input from weathering of the nearby Superior craton. Economically, the Kipalu maybe classified as a low grade taconitic ore. Unlike most economic iron formations such as the Hamersley in Northwest Australia it has not been enriched by supergene processes. The lack of secondary upgrading is attributed to immediate cover by flood basalts and burial by deep marine sediments.
Recommended Citation
Masters, James George, "Depositional History of the Kipalu Iron Formation: Belcher Islands, Nunavut, Canada" (2007). Digitized Theses. 5010.
https://ir.lib.uwo.ca/digitizedtheses/5010