South Atlantic GeoB2107-3 30KYr Silicon Isotope Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: Please cite original reference when using these data, plus the data file URL and date accessed. NAME OF DATA SET: South Atlantic GeoB2107-3 30KYr Silicon Isotope Data LAST UPDATE: 12/2011 (Original receipt by WDC Paleo) CONTRIBUTORS: Hendry, K.R., L.F. Robinson, M.P. Meredith, S. Mulitza, C.M. Chiessi, and H. Arz. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2011-154 WDC PALEO CONTRIBUTION SERIES CITATION: Hendry, K.R., et al. 2011. South Atlantic GeoB2107-3 30KYr Silicon Isotope Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2011-154. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Hendry, K.R., L.F. Robinson, M.P. Meredith, S. Mulitza, C.M. Chiessi, and H. Arz. 2012. Abrupt changes in high-latitude nutrient supply to the Atlantic during the last glacial cycle. Geology, doi: 10.1130/G32779.1 First published online December 16, 2011 ABSTRACT: The supply of nutrients to the low-latitude thermocline is largely controlled by intermediate depth waters formed at the surface in the high southern latitudes. Silicic acid is an essential macronutrient for diatoms, which are responsible for a significant portion of marine carbon export production. Changes in ocean circulation, such as those observed during the last deglaciation, would influence the nutrient composition of the thermocline and, therefore, the relative abundance of diatoms in the low latitudes. Here we present the first record of the silicic acid content of the Atlantic over the last glacial cycle. Our results show that at intermediate depths of the South Atlantic the silicic acid concentration was the same at the Last Glacial Maximum (LGM) as it is today, overprinted by high silicic acid pulses that coincided with abrupt changes in ocean and atmospheric circulation during Heinrich Stadials and the Younger Dryas. We suggest these pulses were caused by changes in intermediate water formation resulting from shifts in the subpolar hydrological cycle, with fundamental implications for the nutrient supply to the Atlantic. GEOGRAPHIC REGION: South Atlantic PERIOD OF RECORD: 30 KYrBP - present FUNDING SOURCES: DATA FILE URLS: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hendry2012/hendry2012.txt ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hendry2012/hendry2012.xls DESCRIPTION: This file contains the silicon isotope compositions (denoted by d30Si relative to NBS28) of sponge spicules extracted from GeoB2107-3. The spicules were cleaned using hydrogen peroxide and dissolved in sodium hydroxide solution; the solutions were purified by passing through a cation exchange resin. Analysis was carried out using the Neptune MC-ICP-MS at Woods Hole Oceanographic Institution. Reproducibility is plus/minus 0.16 per mil (2sd). Age model is based on radiocarbon dates, and tuned to the Antarctic deuterium record. GeoB2107-3: 27.18°S, 46.45°W, 1048m depth. DATA: Hendry et al. 2012 GeoB2107-3 d30Si data Depth(cm) Age(ky) d30Si(per mil) 6.5 1.6 -1.27 16.5 3.1 -1.75 24.5 4.3 -1.39 41.5 6.7 -1.34 46 7.3 -1.29 61 9.3 -1.34 70 11.8 -1.02 72 12.9 -3 76.5 12.9 -1.94 76.5 13.4 -1.56 86 13.6 -1.14 92 13.8 -1.8 95.5 14.6 -0.93 105.5 15.5 -0.94 110.5 16.5 -1.5 116 17.3 -1.6 121 18.3 -1.37 126 19.1 -1.25 136 21.7 -1.33 146 22.6 -1.46 156 24.3 -1.48 161.5 26.2 -1.94 166.7 28 -2.01 171.5 28.9 -1.43 176.5 29.4 -1.53 181.5 29.8 -1.06 186.5 30.3 -1.35