Quantitative Analysis of Deep Water Agglutinated Foraminiferal Assemblages Across Marly Dissolution Intervals in the Early Eocene, Contessa Road Section Italy

Sarah Heal, University College London, Dept of Earth Sciences, London, England, [email protected]

A sequence of limestones and marls from the Early Eocene are recorded within the Scaglia Rossa Formation at the Contessa Road section, Italy. A study of the Deep Water Agglutinated Foraminiferal (DWAF) present reveals that assemblages record the effects of environmental perturbations on benthic communities. Morphogroup analysis is performed on acid residues, and fluctuations in the relative proportions of environmentally sensitive species are noted.

Fluctuations within faunal groups with certain feeding preferences show a distinct correlation with the changes in substrate. An increase in infaunal species within marl-rich layers is interpreted as indicative of an increase in productivity over these intervals. One substantial, thick marl-rich layer shows a definite increase in proportion of deep infaunal taxa. Shallow infaunal changes are recorded at thinner layers where smaller magnitude climatic fluctuations may have been taking place. Inferences can be made about the nature of these marly layers in respect to their occurrence on a global scale. However, DWAF assemblages alone may be insufficient to shed light on the affinity of the thick marly layer to the Elmo horizon as identified in Lower Eocene sediments on ODP Leg 208.