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Diamonds, diatremes and diatoms: paleoecology of Eocene kimberlite maars in Northern Canada

  Termine & Veranstaltungen

Friday, March 4, 2011 at 11:00 am

Building A19, GFZ Potsdam

Prof. Alexander Wolfe

Department of Earth and Atmospheric Sciences
University of Alberta, Canada

Abstract: Exploration drill-cores associated with the diamond boom in Northern Canada have revealed a range of interesting sedimentary strata associated with post-eruptive infilling of kimberlite diatremes. The most promising sites originate from the Lac de Gras field, where lake sediments and peats of Middle Eocene age (Lutetian Stage: ~40 Ma) are sandwiched between kimberlite and overlying glacigenic deposits. Owing to the protracted tectonic and thermal stability of this portion of the Slave province, we observe very little diagenetic alteration of core materials, which enable detailed investigations of organic remains including, but not limited to, siliceous algae (diatoms and chrysophytes), palynomorphs, and gymnosperm megafossils. This presentation will highlight some of these findings and their implications for paleobiology and paleoclimatology. Of particular relevance is the observation that ecosystems having warm-temperate to subtropical affinities were sustained in the Canadian subarctic at p[CO2] only marginally higher than present, well within levels anticipated by the end of the present century.