• Late Quaternary Pteropod Preservation in Eastern North Atlantic Sediments in Relation to Changing Climate

      Ganssen, G. M.; Troelstra, Simon R.; van der Borg, Klaas; De Jong, A. M. F. (Department of Geosciences, The University of Arizona, 1991-01-01)
      AMS 14C measurements on pteropod shells from eastern North Atlantic deep-sea cores reveal distinct periods of aragonite preservation during the last 16,000 years. Most preservation spikes coincide with documented periods of climatic change on a scale of 2 x 101 to 2 x 103 years.
    • Shell Hash Dating and Mixing Models for Palimpsest Marine Sediments

      Roy, Peter S. (Department of Geosciences, The University of Arizona, 1991-01-01)
      The dating of palimpsest marine sediments using broken shell fragments (shell hash) is considered to be a necessary but unreliable technique because of the mixed age of the fragments. An analysis of geological mixing models and radiocarbon data on shell hash from sandy sediments on the southeast Australian coast and shelf are used to examine the possibility for simulating the depositional processes, and thus, to better understand the age structure of the deposits.