Speakers Club: Zachary Nelson (UCSB)

Event Date: 

Thursday, May 25, 2017 - 2:00pm

Event Location: 

  • Webb 1100

Title: Late Pleistocene to Holocene environmental history of Devereux Slough

Abstract: Environmental histories of coastal regions are important for providing a historic perspective on restoration projects as well as evaluating tsunami and other coastal hazards. The Devereux Slough estuary is a flooded river valley located in Santa Barbara County of Southern California. In this study I analyze six new cores from Devereux Slough that contain sediments spanning the last 16,000 years in order to provide insights into the past environmental conditions of the estuary. Five facies representing four main environments were identified. These facies include an anthropogenic fill, two distinct estuarine muds, a marine sand and a fluvial silt. Radiocarbon ages from a cerithideopsis californica suggest the slough is subsiding at a rate of 0.73mm/yr which is similar to other fault bound estuaries in the region and place constraints on the location of the estuary-bounding fault. No tsunamis are recorded within the stratigraphy of Devereux Slough at the same time as proposed large earthquakes on the nearby Pitas Point Thrust. However a 3.5 ka sand bed indicates a period of marine inundation, the origin of which is uncertain at this time.