Associate Professor, UQAM / Geotop – U-Pb geochronology
davies.joshua@uqam.ca
Precambrian Sediments
We have recently been interested in understanding the origin of the complex layering in Paleoproterozoic banded iron formations (BIF), which are well preserved in South Africa and also Australia.
The interdisciplinary team involves UQAM, University of Geneva and Utrecht University, and have been applying cyclostratigraphic approaches to understand the origin of the layering in BIF. We have combined high precision U-Pb dating with cyclostratigraphy to show that large scale layering in BIF is likely to have been forced by climatic variations called Milankovitch cycles.
Further work is underway to understand how these cycles relate to the origin of BIF.
We intend to expand this approach to other types of sediments in other Precambrian time periods to understand the role of climate forcing on sediment deposition, early in Earths history.
Zircon from possible ash layers within the BIF
Asbestos within the Kuruman BIF
Zircon from possible ash layers within the BIF
The combination of spectral analysis on the identified cycles within the Kuruman BIF and also high precision U-Pb geochronology indicates that regular cycles of ~5 and ~20m are present within the BIF and that these cycles relate to principle periods of eccentricity