Cocos (Keeling) Islands, Indian Ocean Coral Radiocarbon Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: Cocos (Keeling) Islands, Indian Ocean Coral Radiocarbon Data LAST UPDATE: 8/2006 (Original receipt by WDC Paleo) CONTRIBUTORS: Quan Hua, Colin Woodroffe, Scott Smithers, Mike Barbetti, David Fink IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2006-074 SUGGESTED DATA CITATION: Hua, Q. et al. 2006. Cocos (Keeling) Islands, Indian Ocean Coral Radiocarbon Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2006-074. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Hua, Q., C.D. Woodroffe, S.G. Smithers, M. Barbetti, and D. Fink. 2005. Radiocarbon in corals from the Cocos (Keeling) Islands and implications for Indian Ocean circulation. Geophys. Res. Lett., v.32, L21602, doi:10.1029/2005GL023882. ABSTRACT: Annual bands of a Porites coral from the Cocos (Keeling) Islands, eastern Indian Ocean, were analysed by radiocarbon for 1955-1985 AD. A rapid oceanic response of the site to bomb 14C is found, with a maximum D14C value of 132 per mil in 1975. This value is considerably higher than those for the northwestern Indian Ocean, suggesting that surface waters reaching Cocos are not derived from the Arabian Sea. Instead, D14C values for Cocos and those for Watamu (Kenya) agree well over most of the study interval, suggesting that the South Equatorial Current carries 14C-elevated water rather than 14C-depleted water westward across the Indian Ocean. This implies that oceanic upwelling in the northwestern Indian Ocean is spatially confined with little contribution to the upper limb of the global thermohaline circulation. GEOGRAPHIC REGION: Eastern Indian Ocean, The Cocos (Keeling) Islands. PERIOD OF RECORD: 1955-1985 FUNDING SOURCES: AINSE for AMS 14C measurements (grants 01/207, 02/150P and 04/174) DESCRIPTION: Cocos (Keeling) Islands, Indian Ocean Coral Radiocarbon Data The Cocos (Keeling) Islands are a mid-ocean atoll in the eastern Indian Ocean (96°48'-56'E, 12°04'-13'S). Porites microatoll PP30 (2.7 m in diameter) is located on the eastern side of the atoll from a reef-flat site that is freely connected to the open ocean. The data set includes an annual radiocarbon time series derived from PP30. Radiocarbon analysis was carried out using the ANTARES AMS facility at The Australian Nuclear Science and Technology Organisation (ANSTO). DATA: Cocos (Keeling) Islands, Indian Ocean Coral Radiocarbon Column 1: Lab Code Column 2: Year AD Column 3: D14C ± 1 sigma (per mil) Lab Code Year D14C ± 1 sigma (per mil) OZG153 1955.5 -54.9 ± 2.8 OZG154 1956.5 -48.6 ± 2.9 OZG155 1957.5 -37.6 ± 1.9 OZG156 1958.5 -35.9 ± 2.9 OZG157 1959.5 -35.3 ± 2.7 OZG158 1960.5 -16.2 ± 2.8 OZG159 1961.5 -11.8 ± 3.2 OZG160 1962.5 5.3 ± 2.9 OZG161 1963.5 33.1 ± 4.2 OZF539 1964.5 49.8 ± 3.1 OZG162 1964.5 56.3 ± 4.0 OZG163 1965.5 68.8 ± 3.9 OZG164 1966.5 93.2 ± 4.4 OZG165 1967.5 86.6 ± 4.2 OZG166 1968.5 121.5 ± 4.0 OZG167 1969.5 103.7 ± 3.7 OZH225 1970.5 108.4 ± 3.5 OZG168 1971.5 120.6 ± 4.2 OZH226 1972.5 114.3 ± 3.7 OZG169 1973.5 121.8 ± 4.5 OZG170 1974.5 114.6 ± 3.6 OZG171 1975.5 131.7 ± 3.3 OZH227 1976.5 117.9 ± 3.8 OZG172 1977.5 124.9 ± 4.2 OZG173 1978.5 123.0 ± 4.7 OZG174 1979.5 130.9 ± 4.4 OZG175 1980.5 103.5 ± 4.4 OZG176 1981.5 118.7 ± 4.1 OZG177 1982.5 111.4 ± 4.0 OZG178 1983.5 101.5 ± 4.3 OZG179 1984.5 101.5 ± 4.1 OZG180 1985.5 100.3 ± 4.3