Browsing by Author "Cohen, Phoebe A"

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    • Calibrating the Cryogenian 

      Macdonald, Francis Alexander; Schmitz, Mark D.; Crowley, James L.; Roots, Charles F.; Jones, David S.; Maloof, Adam C.; Strauss, Justin Vincent; Cohen, Phoebe; Johnston, David T; Schrag, Daniel P. (American Association for the Advancement of Science (AAAS), 2010)
      The Neoproterozoic was an era of great environmental and biological change, but a paucity of direct and precise age constraints on strata from this time has prevented the complete integration of these records. We present ...

    • Early Neoproterozoic scale microfossils in the Lower Tindir Group of Alaska and the Yukon Territory 

      Macdonald, Francis Alexander; Cohen, Phoebe; Dudas, Francis Ő.; Schrag, Daniel P. (Geological Society of America, 2010)
      The Tindir Group is a <4-km-thick Neoproterozoic succession exposed in the Tatonduk inlier of east-central Alaska and the western Yukon Territory. The Tindir Group is informally divided into the Lower Tindir Group, which ...

    • Eukaryotic Organisms in Proterozoic Oceans 

      Knoll, Andrew Herbert; Javaux, Emmanuelle J.; Hewitt, David; Cohen, Phoebe A (Royal Society, The, 2006)
      The geological record of protists begins well before the Ediacaran and Cambrian diversification of animals, but the antiquity of that history, its reliability as a chronicle of evolution and the causal inferences that can ...