A speleothem-based Mid-Holocene Precipitation Reconstruction for West-Central Florida

• Published in: The Holocene
• Main Authors: Pollock, Anna L., van Beynen, Philip E., DeLong, Kristine L., Polyak, Victor J., Asmerom, Yemane
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Digital Commons @ University of South Florida 2017
• Subjects: Florida; mid-Holocene; North America; paleoclimate; precipitation; speleothem; subtropics; Earth Sciences; Nash; North Atlantic; North Atlantic oscillation
• Online Access: https://digitalcommons.usf.edu/geo_facpub/2086; https://doi.org/10.1177/0959683616678463

The mid-Holocene was the warmest segment of the current interglacial and possessed a weak latitudinal temperature gradient, which impacted climate teleconnections and thus precipitation variability. Our window into the mid-Holocene climate is a high-resolution (near annual) stalagmite stable isotope-based paleoprecipitation record from Brown’s Cave in West-Central Florida. The oxygen isotopic (δ18O) time series is tied to a uranium-series (U-series) chronology that covers a 2000-year period from 6.6 to 4.6 ka. We compared our reconstruction with another speleothem δ18O-derived precipitation record near our study area that spans the last 1600 years. That comparison shows that the mid-Holocene was drier than the last 1.6 millennia. We posit the cause of this aridity was a westward expansion of the North Atlantic Subtropical High (NASH) coupled with changes in the planetary boundary layer in the Gulf of Mexico. Time-series analysis of our oxygen isotopic record found little evidence of any teleconnections originating from the North Atlantic including the North Atlantic Oscillation during the mid-Holocene. However, there is some indication of a weak, quasi-persistent oscillation within the temporal periodicity of the Atlantic Multidecadal Variability.