NOAA/WDS Paleoclimatology - Springer et al. 2008 Buckeye Creek Cave Holocene Isotope and Sr/Ca Data

STUDY NOTES: Decadal resolution stable isotope and trace metal data from Buckeye Creek Cave stalagmite BCC-002, spanning 7,000 years BP to present (U-Th dated). Records solar-driven cycles in relative moisture abundance, and land disturbances by Native Americans in the Late Holocene. Buckeye Creek Cave, West Virginia, east-central USA: 37°58.57'N, 80°23.98'W, 600m elevation. LAST UPDATE: 8/2014 - correction of depth series: Removal of incorrect duplicate depth value 11.0 mm, depth values greater than 11 mm shifted upward by one sample. No data values or ages affected.
ABSTRACT SUPPLIED BY ORIGINATOR: Elevated Sr/Ca ratios and δ13C values in Holocene-age stalagmite BCC-002 from east-central North America record six centennial-scale droughts during the last five North Atlantic Ocean ice-rafted debris (IRD) episodes, previously ascribed to solar irradiance minima. Spectral and cross-spectral analyses of the multi-decadal resolution Sr/Ca and δ13C time series yield coherent ~200 and ~500 years periodicities. The former is consistent with the de Vries solar irradiance cycle. Cross-spectral analysis of the Sr/Ca and IRD time series yields coherent periodicities of 715- and 455-years, which are harmonics of the 1,450 ± 500 year IRD periodicity. These coherencies corroborate strong visual correlations and provide convincing evidence for solar forcing of east-central North American droughts and strengthen the case for solar modulation of mid-continent climates. Moisture transport across North America may have lessened during droughts because of weakened north-south temperature and pressure gradients caused by cooling of the tropical Pacific and Atlantic Oceans.