Chronology and paleoenvironments during the late Weichselian deglaciation of the southwest Iceland shelf

Abstract

Foraminifera, sedimentology, and tephra geochemistry in core 93030‐006 LCF from the southwestern Iceland shelf were used to reconstruct paleoenvironments between 12.7 and 9.4 14 C ka BP. Seismic‐reflection profiles place the core in glacial‐marine and marine sediments within one meter of the underlying glacial till. Foraminifers in the earliest glacial‐marine sediments provide a record of ice‐distal conditions and immigration of slope species onto the shelf in association with warm Atlantic water. Meltwater increased during the Allerød under a weakened Atlantic water influence. Arctic conditions began by 11.14 14 C ka BP with an abrupt increase in meltwater and near exclusion of boreal fauna from the shelf. Meltwater diminished in the early Younger Dryas, coinciding with sea‐surface cooling between 11.14 and 10.5 14 C ka BP. A slight warming recorded in the uppermost glacial‐marine sediments was interrupted by an inferred jökulhlaup event emanating from glacier ice on the Western Volcanic Zone. Retreat of the ice margin from the sea sometime between c. 10.3 and 9.94 14 C ka BP coincided with this event. The onset of postglacial marine sedimentation occurred along with increasing evidence of Atlantic water c. 9.94 14 C ka BP and was interrupted by a short‐lived Pre‐boreal cooling of the Irminger Current c. 9.91 14 C ka BP. Conditions similar to those today were established by 9.7 14 C ka BP.