27 Past Sedimentation Records and Insight for Predicting Future Climate Impacts to Pacific Shores (Posters)

Wednesday, 24 May 2017
8:30 AM - 5:00 PM
Room 323A/B/C

LATE HOLOCENE CLIMATE VARIABILITY FROM ST. CROIX, USVI REEF CORALS

Paper number: 27-3
Program: Technical Sessions
Time: 8:30 AM – 5:00 PM

Authors

  • Dakota Keene Presenting Author
    California State University Sacramento, Sacramento, CA
  • Amy Wagner
    California State University Sacramento, Sacramento, CA
  • Chad S. Lane
    University of North Carolina Wilmington, Wilmington, NC

Abstract

We present a multi-century climate record using the skeletal geochemistry of Siderastrea siderea and Orbicella faveolata corals collected near Salt River Bay, St. Croix, USVI. Samples ranging in age from modern to approximately 2100 years old were collected, slabbed, and milled with each coral representing approximately 25 to 40 years of growth. Skeletal δ18O values correlate strongly with sea surface temperature (SST) and sea surface salinity (SSS). Seasonal variations in skeletal δ18O values are controlled primarily by changes in SST and secondarily by inferred changes in water δ18O due to precipitation and runoff. Analysis of these variations in the St. Croix corals indicates either a gradual rise in SST or a decline in SSS over the last several centuries. The remaining coral slabs were analyzed with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) for trace element geochemistry. Unusually high ratios of Ba/Ca correspond with an influx of sediment typically associated with increased runoff from storm events. The presence of spikes in Ba/Ca may indicate that seasonal variations in skeletal δ18O values result from a decline in SSS instead of a gradual rise in SST.

Geological Society of America Abstracts with Programs. Vol. 49, No. 4

doi: 10.1130/abs/2017CD-292891

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