Publication Date:
2022-05-25
Description:
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in A stalagmite test of north atlantic SST and iberian hydroclimate linkages over the last two glacial cycles. Climate of the Past, 14(12), (2018); 1893-1913., doi:10.5194/cp-14-1893-2018.
Description:
Close coupling of Iberian hydroclimate and North Atlantic sea surface temperature (SST) during recent glacial periods has been identified through the analysis of marine sediment and pollen grains co-deposited on the Portuguese continental margin. While offering precisely correlatable records, these time series have lacked a directly dated, site-specific record of continental Iberian climate spanning multiple glacial cycles as a point of comparison. Here we present a high-resolution, multi-proxy (growth dynamics and δ13C, δ18O, and δ234U values) composite stalagmite record of hydroclimate from two caves in western Portugal across the majority of the last two glacial cycles (∼220 ka). At orbital and millennial scales, stalagmite-based proxies for hydroclimate proxies covaried with SST, with elevated δ13C, δ18O, and δ234U values and/or growth hiatuses indicating reduced effective moisture coincident with periods of lowered SST during major ice-rafted debris events, in agreement with changes in palynological reconstructions of continental climate. While in many cases the Portuguese stalagmite record can be scaled to SST, in some intervals the magnitudes of stalagmite isotopic shifts, and possibly hydroclimate, appear to have been somewhat decoupled from SST.
Description:
This work was supported by the Center for Global and Regional Environmental Research, Cornell College (to Rhawn F. Denniston), and the US National Science Foundation (grant BCS-1118155 to Jonathan A. Haws, BCS-1118183 to Michael M. Benedetti, and AGS-1804132 to Caroline C. Ummenhofer). Field sampling was performed under the auspices of IGESPAR (to Jonathan A. Haws) and Associação de Estudos Subterrâneos e Defesa do Ambiente. Brandon Zinsious and Stephen Rasin contributed to fieldwork at BG, and Zachary LaPointe assisted with radioisotopic analyses; Suzanne Ankerstjerne performed stable isotope measurements. This paper benefitted tremendously from discussions with Maria F. Sánchez Goñi, David Hodell, and Chronis Tzedakis. We thank five anonymous reviewers who substantially improved this paper's scope and clarity through detailed and thoughtful assessments. Stable and U-series isotope data are available at the NOAA National Centers for Environmental Information website.
Repository Name:
Woods Hole Open Access Server
Type:
Article
Permalink
