BENTHIC FORAMINIFERAL DISTRIBUTION ACROSS THE YPRESIAN-LUTETIAN BOUNDARY; THE RIO SAMBRE SECTION, JAMAICA

The Rio Sambre Section of North Central Jamaica spans the Early to Middle Eocene (Ypresian/Lutetian) transition. The section contains abundant and diverse assemblages of benthic and planktonic foraminifera. The middle bathyl sedimentary deposits of the Rio Sambre Section are comprised of marine chalks, mudstones, and minor turbidic sandstones of the Langley Member of the Richmond Formation and the lower Font Hill Formation. These sediments were deposited in the Wagwater Trough in two separate depositional stages; an initial fault controlled deposition followed by a secondary basin wide carbonate platform deposition and subsidence. Benthic foraminifera throughout the section compromise approximately 10%-35% of the total foraminifera count. The benthic foraminifera are dominated by calcareous taxa with few agglutinated species; this is likely due to preservation and taphonomic effects. This study investigates the effect of sedimentation and other influential parameters on benthic foraminiferal distribution across the Ypresian/Lutetian boundary at the Rio Sambre Section.

Some common benthic foraminifera from the Rio Sambre Section include: various Cibicidoides species , Anomalinoides species, Planulina sp, Gyroidinoides girardanus, Laevidentalina gracilis, Globobulimina pyrula, Pleurostromella species, Siphonodosaria species, Nodosaria species, and Nuttallides trüempyi. Some of the more uncommon benthic foraminifera include: Cassidulina spinifera, Cibicidoides pseudoungerianus, Cibicidoides subspiratus, Aragonia aragonensis, Ellipsoidella kugleri, various Lenticulina species, Quinqueloculina sp, Spiroplectammina sp, Pullenia sp, Astracolus sp, Hanzawaia ammophila, Nodosaria longiscata, Pyramidulina sp., and Uvigerinasp.

It is also worth noting that this section contains a similar assemblage of benthic foraminifera to that of the Early to Middle Eocene deposits at the Fortuna Section in southeastern Spain.