DOI: 10.25921/gtx6-gk85
title: NOAA/WDS Paleoclimatology - La Garma Cave Geochemical Data from 13900 to -26 Cal Yr BP

description: Precisely-dated, high-resolution stable isotope and trace element data from a stalagmite from La Garma Cave, northern Spain, reveal several stages of distinct climatic variability along the northern Iberian Atlantic margin, and provide new constraints on the latitude of North Atlantic westerlies during the Younger Dryas Event (YD). Westerly wind position (reconstructed using sub-annually resolved Mg data as a proxy for sea spray contributions associated with wind strength at this coastal cave site) during the early YD (12.85–12.15 kyr) oscillated meridionally, resembling the decadal-scale component of the modern North Atlantic Oscillation (NAO). Northward repositioning of westerly storm tracks over northern Iberia began at ∼12.15 kyr, consistent with other high-resolution wind proxy reconstructions from central and northern Europe, but occurred more gradually nearer the Atlantic margin. From ∼12.15 kyr to the YD termination, atmospheric circulation resembled a persistently positive NAO, with westerlies reaching their maximum northward extent at 11.8 kyr (reflected by a Mg concentration minimum at this time). Air temperature (reflected by our δ18O data) and Iberian wind strength were predominantly coupled throughout the YD suggesting that temperature modulated sea-ice extent, and consequently controlled westerly wind latitude. However our data suggest that abrupt warming at 12.1 kyr was followed by much more gradual northward shifts in westerly position, and that a lag existed between the warming and sea-ice retreat. This gradual return of the westerlies to the north beginning at 12.1 kyr is consistent with inferred changes in wind strength at other European sites. Additionally, atmospheric circulation inferred from our northern Iberian wind strength proxy record generally tracked low-frequency meridional shifts in Intertropical Convergence Zone position, corroborating past research that suggested closely coupled low- and high-latitude atmospheric teleconnections over this period.
description: Data contributed as part of SISAL v3 Global Speleothem Isotope and Trace Element Database (https://doi.org/10.25921/jajq-qg60). Notes from the SISAL database: The elevation of the cave (85 masl) differs with the elevation of the lower gallery from which La Garma speleothems were collected (59 masl). The C14 data (not provided here) is available in Rudzka et al., 2011 (10.1016/j.gca.2011.05.022). GAR-01_drill (SISAL entity_id=650) and GAR-01_laser data (entity_id= 651 and 652) were obtained from GAR-01 stalagmite using a handheld conventional drill (drill) at ~2.2 mm spatial resolution and by laser ablation (LA-GC-IRMS) with a ~500 micron resolution. GAR-01_laser_d13C (entity_id=652) and GAR-01_laser_d18O (entity_id=651) series are treated separately in the database because there is a small non-constant offset in the corresponding age-depth models. Baldini et al., 2015 (10.1016/j.epsl.2015.03.015) used the StalAge Algorithm but the ages determined using COPRA are provided here. There is excellent agreement between the two age models over the Younger Dryas Interval (see Baldini et al., QSR, in review).