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2010-11 speaker tour:
For further details and dates, please contact the Tour Coordinator, Ian Spooner (ian.spooner@acadiau.ca).
Dr. Peir Pufahl (peir.pufahl@acadiau.ca)
Dept. of Earth and Environmental Science, Acadia University
January 25: St. Francis Xavier University
March 8: Dalhousie University
March 25: Memorial University
Title: Precambrian carbonates and the evolution of the atmosphere
Abstract: Bioelemental sediments, a new term that encompasses iron formation, chert, and phosphorite, provide the framework for understanding early Earth evolution. Because bioelemental sediments are composed of the nutrient elements, Fe, Si, and P, their precipitation is intimately linked to biological processes that modify ocean-atmosphere chemistry. This talk highlights how sedimentology and the use of modern stratigraphic principles are used to interpret the microbial ecology and geochemistry of Precambrian bioelemental depositional systems.
Dr. Yana Fedortchouk (yana@DAL.CA)
Dept. of Earth Sciences, Dalhousie University
January 12: Acadia University
January 26: Saint Mary's University
February 10 or 11: UNB-Fredericton
Title: Diamonds: A window into the Mantle
Abstract: Diamonds store an incredible record of Earth's history due to their Archean ages and the residence at great depths as deep as the lower mantle. Diamonds come to the surface by entrainment in kimberlites — the deepest mantle-derived magmas. Kimberlites are also famous for their extremely complex composition, poorly understood origin, presumably explosive eruptions indicating very volatile-rich nature, and the absence of the modern examples. In my talk I will show how we can use diamonds to constrain conditions in kimberlite magmas and in various diamond-bearing reservoirs in the mantle. Diamonds undergo partial dissolution during transportation in kimberlites and during residence in the mantle. The morphology of dissolution features strongly depends on the composition and the conditions of the diamond-destructive fluids. Combination of high-pressure-temperature experiments with morphological studies of the natural diamond parcels demonstrated a strong link between diamond dissolution features and the geology of kimberlite pipes. Surface features are different on diamonds recovered from volcaniclastic and hypabyssal kimberlites reflecting presence or absence of the free fluid phase and the mechanism of kimberlite eruption. Further I will show how diamond morphology can help us to constrain the fluid history in various mantle reservoirs and to learn more about the complex evolution of subcratonic mantle.
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