T86 Paleoenvironmental Reconstructions from Biogenic Carbonates I

Monday, 5 November 2018
8:00 AM - 12:00 PM
Room 140

HIGH-RESOLUTION PALEOCLIMATE RECONSTRUCTION OVER THE LAST TWO MILLENNIA IN THE EASTERN SUBTROPICAL ATLANTIC OCEAN

Paper number: T86-7
Program: Technical Sessions
Time: 9:25 AM – 9:40 AM

Authors

Abstract

The Little Ice Age (LIA; 1400-1800 AD) and the Medieval Climate Anomaly (MCA; 1000-1300 AD) are well known rapid climate episodes which occurred during the late Holocene. These events are recorded in a variety of paleoclimate proxies, however many of the previously studied proxies are single-season or low-resolution and are concentrated in mid to high latitudes of the Northern Hemisphere. Few high-resolution records are available from subtropical latitudes, like the Canary Island Archipelago of Spain, located between 27 and 29 °N. The archipelago sits at the confluence of the West African upwelling zone and the Canary Current, making it an ideal location to study regional and hemispheric climate variability. In this study, the oxygen isotope composition of radiocarbon-dated archaeological shells of Phorcus atratus (Gastropoda: Trochoidea) was studied along shell growth direction to infer seasonal sea surface temperature (SST) over the last two millennia. Preliminary results indicate that LIA shells grew at average SSTs that were reduced by 1-2 °C, but the magnitude of seasonality was similar to that of the late 20th century. Thus, the LIA was noticeable but subdued in the Canary Archipelago compared to higher latitude regions that appear to have experienced cooling events from 2-4 °C. In addition, Phorcus shells suggest that the magnitude of seasonality and average SSTs during the MCA were analogous to those of the late 20th century. Ongoing research using other contemporaneous Patellidae taxa preserved in archaeological sites will allow us to further test and verify the observed climate trends.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-319468

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