CHARACTERIZATION OF MODERN BENTHIC FORAMINIFERAL ASSEMBLAGES FOR PALEO-TSUNAMI DETECTION IN SUR LAGOON, OMAN

The aim of this study is to provide baseline data for interpreting the foraminiferal record of the November 28, 1945 tsunami that was found in cores from Sur lagoon, Oman. The tsunami was generated by a 7.8 magnitude earthquake approximately 100 km south of Karachi and resulted in over 4000 deaths. Sur Lagoon, Oman, is a shallow open-ended microtidal lagoon that receives a daily influx of saline marine water through tidal activity and periodic freshwater input from its surrounding wadi system during the monsoon season. In addition, the configuration of the lagoon allows for capture of lower frequency but higher magnitude events such as storm surges and tsunami originating in the Indian Ocean and the Gulf of Oman. In 2006, 119 surface sediment samples were collected on an imposed grid at 100 m intervals. The samples encompass a variety of microenvironments and are presently being studied with respect to foraminiferal fauna and taphonomic trends (e.g. % fragments). Foraminiferal assemblages will be compared and contrasted with lithologic facies and a Digital Elevation Model (DEM) that was created at 10 m spacing. Preliminary Q-mode cluster analysis results indicate that mangrove, tidal channel and mudflat biofacies can be clearly discriminated. This study will supplement the presently sparse foraminiferal catalogue for this region, and will serve as a foundation for micropaleontological analysis of down-core units, allowing for the establishment of critical environmental changes (e.g. the 1945 tsunami) through the paleo-record for this location.