Chagos Archipelago Coral Oxygen Isotope Data --------------------------------------------------------------------- NOAA Paleoclimatology Program and World Data Center for Paleoclimatology, Boulder --------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Chagos Archipelago Coral Oxygen Isotope Data LAST UPDATE: 11/2004 (Original Receipt by WDC Paleo) CONTRIBUTORS: Miriam Pfeiffer and Wolf-Christian Dullo IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2004-070 SUGGESTED DATA CITATION: Pfeiffer, M., et al.. 2004. Chagos Archipelago Coral Oxygen Isotope Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-070. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Pfeiffer, M., W.-C. Dullo, and A. Eisenhauer. 2004. Variability of the Intertropical convergence Zone recorded in coral isotopic records from the central Indian Ocean (Chagos Archipelago). Quaternary Research 61: 245-255 ABSTRACT: We have analyzed the stable oxygen isotopic composition of two Porites corals from the Chagos Archipelago, which is situated in the geographical center of the Indian Ocean. Coral d18O at this site reliably records temporal variations in precipitation associated with the Intertropical Convergence Zone (ITCZ). Precipitation maxima occur in boreal winter, when the ITCZ forms a narrow band across the Indian Ocean. The Chagos then lies within the center of the ITCZ, and rainfall is strongly depleted in d18O. A 120-yr coral isotopic record indicates an alternation of wet and dry intervals lasting 15 to 20 yr. The most recent 2 decades are dominated by interannual variability, which is tightly coupled to the El Nino-Southern Oscillation (ENSO). This is unprecedented in the 120 yr of coral record. As the ITCZ is governed by atmospheric dynamics, this provides evidence of a major change in the coupled ENSO-monsoon system. ADDITIONAL REFERENCE: Timm, O., M. Pfeiffer, and W.-C. Dullo. 2005. Nonstationary ENSO-precipitation teleconnection over the equatorial Indian Ocean documented in a coral from the Chagos Archipelago. Geophys. Res. Lett., Vol. 32, No. 2, L02701 http://dx.doi.org/10.1029/2004GL021738 19 January 2005 GEOGRAPHIC REGION: Indian Ocean PERIOD OF RECORD: 1961 -1995 AD DESCRIPTION: Bimonthly resolved stable oxygen isotope record from a modern coral collected at Peros Banhos Atoll (central Indian Ocean). Coral d18O is influenced by rainfall associated with the Intertropical Convergence Zone. Stable isotope analysis: Carbonate powders were reacted with 100 % phosphoric acid at 75°C in an online carbonate preparation line (Carbo-Kiel-single sample acid bath) connected to a Finnigan Mat 252 mass spectrometer. All values are reported in per mil relative to PDB by assigning a d18O value of -2.20 to NBS-19. Reproducibility was checked by replicate analysis of laboratory standards and is better than ±0.05 for d18O. Sampling resolution: The core was sampled at 2 mm increments. Age model: The most negative isotopic value in any given year was assigned to February 15. All other age assignments are obtained through linear interpolation between these anchor points. Sample site is Peros Banhos Atoll in the Chagos Archipelago, central Indian Ocean. 5 deg., 26.4' South, 71 deg., 45.86' East, 1.8 M. water depth. DATA: 1. Peros Banhos Atoll Coral Oxygen Isotope Data Column 1: Calendar Year A.D. Column 2: d18O, per mil PDB Year A.D. d18O 1995.625 -5.1 1995.458 -4.96 1995.292 -5.195 1995.125 -5.29 1994.958 -5.198 1994.792 -5.273 1994.625 -5.115 1994.458 -4.963 1994.292 -5.017 1994.125 -5.18 1993.958 -4.963 1993.792 -4.993 1993.625 -4.915 1993.458 -4.787 1993.292 -4.81 1993.125 -5.06 1992.958 -5.04 1992.792 -4.88 1992.625 -4.9 1992.458 -4.79 1992.292 -4.81 1992.125 -5.18 1991.958 -5.155 1991.792 -5.05 1991.625 -4.94 1991.458 -4.877 1991.292 -4.903 1991.125 -5.1 1990.958 -4.912 1990.792 -4.91 1990.625 -4.825 1990.458 -4.827 1990.292 -4.968 1990.125 -5.03 1989.958 -4.83 1989.792 -4.723 1989.625 -4.735 1989.458 -4.84 1989.292 -4.977 1989.125 -5.06 1988.958 -4.828 1988.792 -4.89 1988.625 -4.93 1988.458 -4.87 1988.292 -4.998 1988.125 -5.1 1987.958 -4.81 1987.792 -4.96 1987.625 -5.03 1987.458 -4.91 1987.292 -4.87 1987.125 -5.27 1986.958 -5.212 1986.792 -4.82 1986.625 -4.65 1986.458 -4.79 1986.292 -5.042 1986.125 -5.1 1985.958 -4.88 1985.792 -4.857 1985.625 -4.835 1985.458 -4.773 1985.292 -4.888 1985.125 -4.95 1984.958 -4.8 1984.792 -4.763 1984.625 -4.705 1984.458 -4.607 1984.292 -4.593 1984.125 -4.96 1983.958 -4.785 1983.792 -4.91 1983.625 -4.935 1983.458 -4.937 1983.292 -5.082 1983.125 -5.24 1982.958 -5.21 1982.792 -5.1 1982.625 -4.68 1982.458 -4.81 1982.292 -5.02 1982.125 -5.08 1981.958 -5.04 1981.792 -4.847 1981.625 -4.78 1981.458 -4.88 1981.292 -4.957 1981.125 -5.17 1980.958 -4.998 1980.792 -4.835 1980.625 -4.745 1980.458 -4.79 1980.292 -4.79 1980.125 -4.79 1979.958 -4.743 1979.792 -4.6 1979.625 -4.825 1979.458 -4.925 1979.292 -4.988 1979.125 -5.1 1978.958 -4.873 1978.792 -4.76 1978.625 -4.87 1978.458 -4.797 1978.292 -4.763 1978.125 -5.12 1977.958 -4.847 1977.792 -4.713 1977.625 -4.76 1977.458 -4.713 1977.292 -4.873 1977.125 -5.12 1976.958 -5.092 1976.792 -4.997 1976.625 -4.905 1976.458 -4.82 1976.292 -4.845 1976.125 -5.11 1975.958 -4.975 1975.792 -4.94 1975.625 -4.855 1975.458 -4.72 1975.292 -4.99 1975.125 -5.15 1974.958 -4.875 1974.792 -4.813 1974.625 -4.725 1974.458 -4.713 1974.292 -4.86 1974.125 -4.86 1973.958 -4.863 1973.792 -4.81 1973.625 -4.85 1973.458 -4.673 1973.292 -4.823 1973.125 -4.94 1972.958 -4.83 1972.792 -4.69 1972.625 -4.785 1972.458 -4.74 1972.292 -4.91 1972.125 -5.14 1971.958 -5.108 1971.792 -4.853 1971.625 -4.8 1971.458 -4.82 1971.292 -4.885 1971.125 -4.93 1970.958 -4.657 1970.792 -4.697 1970.625 -4.64 1970.458 -4.647 1970.292 -4.8 1970.125 -4.95 1969.958 -4.72 1969.792 -4.74 1969.625 -4.575 1969.458 -4.51 1969.292 -4.96 1969.125 -5.07 1968.958 -5.03 1968.792 -4.75 1968.625 -4.67 1968.458 -4.73 1968.292 -4.73 1968.125 -4.93 1967.958 -4.863 1967.792 -4.68 1967.625 -4.63 1967.458 -4.627 1967.292 -4.757 1967.125 -5.03 1966.958 -5.05 1966.792 -4.98 1966.625 -4.94 1966.458 -4.66 1966.292 -4.645 1966.125 -5 1965.958 -4.827 1965.792 -4.657 1965.625 -4.78 1965.458 -4.773 1965.292 -4.85 1965.125 -5.11 1964.958 -4.86 1964.792 -4.82 1964.625 -4.58 1964.458 -4.63 1964.292 -5.05 1964.125 -5.05 1963.958 -4.673 1963.792 -4.693 1963.625 -4.685 1963.458 -4.81 1963.292 -5.03 1963.125 -4.86 1962.958 -4.973 1962.792 -4.943 1962.625 -4.88 1962.458 -4.783 1962.292 -4.687 1962.125 -5.21 1961.958 -4.823 1961.792 -4.507 1961.625 -4.67 1961.458 -4.667 1961.292 -4.84 1961.125 -5.07