Barbados Coral Oxygen Isotope Data: Readme file --------------------------------------------------------------------- NOAA Paleoclimatology Program and World Data Center for Paleoclimatology, Boulder --------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Barbados Coral Oxygen Isotope Data LAST UPDATE: 2/2001 (Original receipt by WDC Paleo) CONTRIBUTORS: T.P. Guilderson (1,2,3), R.G. Fairbanks (1,2), J.L. Rubenstone (1) 1. Lamont-Doherty Earth Observatory Rte 9-W Palisades, NY 10964 2. Dept. of Earth and Environmental Sciences Columbia University, NY 3. now at: Center for Accelerator Mass Spectrometry, LLNL and the Institute of Marine Sciences, University of California, Santa Cruz IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2001-010 SUGGESTED DATA CITATION: Guilderson, T.P, et al., 2001, Barbados Coral Oxygen Isotope Data, IGBP PAGES/World Data Center for Paleoclimatology, Boulder Data Contribution Series #2001-010. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: T.P. Guilderson, R.G. Fairbanks, J.L. Rubenstone, Tropical Atlantic coral oxygen isotopes: glacial-interglacial sea surface temperatures and climate change. Marine Geology, 172, 75-89, 2001. ADDITIONAL REFERENCES: Bard, E., Arnold, M., Fairbanks, R.G., and Hamelin, B., 1993. 230Th-234U and 14C ages obtained by mass spectrometry on corals. Radiocarbon , 35, 191-199. Fairbanks, R.G., 1989. A 17,000-year glacio-eustatic sea level record; influence of glacial melting rates on the Younger Dryas event and deep-ocean circulation. Nature, 342, 637-642. Fairbanks, R.G., 1990. The Age and Origin of the "Younger Dryas Climate Event" in Greenland Ice Cores. Paleoceanography, 5(6), 937-948. Guilderson, T. P., Fairbanks, R.G., and Rubenstone, J.L., 1994. Tropical temperature variations since 20,000 years ago: modulating interhemispheric climate change. Science, 263, 663-665. GEOGRAPHIC REGION: Tropical Atlantic, Barbados, ~ 13°N 60°W PERIOD OF RECORD: Late Pleistocene FUNDING SOURCES: National Science Foundation (US) to RGF. LIST OF FILES: Readme_barbados.txt (this file), Barbados_coral18o.txt. DESCRIPTION: Coral-based delta18O time-series derived from measurements made on submerged or drowned coral reef sequence. The core samples used have been described elsewhere (cf. Fairbanks, 1989; Guilderson et al., 1994). Measurements were made on three different species of corals: the reef-crest Acropora palmata and the mixed or buttress zone species Montastrea annularis and Porites asteroides. Linear growth rates of individual corals were determined by using the low density to high-density band distance as an approximate annual chronometer. To minimize growth-rate kinetic induced effects, we only analyzed specimens with similar linear growth rates and from the same relative position within the corals. Typical linear extension rates were 5mm/year for all specimens analyzed and ranged from 3 to 7 mm/year. Two to four parallel transects encompassing 4-8 years per transect were extracted using a micro dental drill along the main vertical growth axis. To minimize the potential for skeletal inhomogeneities, we attempted to only sample theca (walls), except for the P. asteroides specimens whose skeletal architecture is too fine for theca sampling. A. palmata specimens were only sampled along the upper growing surface as deduced from the skeletal architecture observed in x-radiographs. We used x-ray diffraction analysis of drilled and ground specimens to confirm that the aragonite was pristine as indicated by the absence of any calcite peaks (detection limit 0.5 weight percent). The sampling protocol did not convert aragonite to calcite. Living specimens collected over the last ~20 years were treated in a similar fashion to the offshore cores. Samples (100-200µg) were reacted at 90°C in a Carousel-48 device and analyzed on a Finnigan MAT 251 isotope ratio mass spectrometer. Calibration is through secondary standards calibrated via NBS (now NIST SRM) standards 16, 17, 19, and 20. Analytical precision of concurrently analyzed standards is better than ±0.05” (1-sigma) for both oxygen and carbon. Data is reported in d-notation relative to Pee Dee Belemnite using the defined values of NBS-20 (d18O -4.14” PDB, d13C -1.06” PDB). We have not corrected the absolute values of our results for the "acid-alpha" difference between aragonite (samples) and calcite (standards). Radiocarbon and 230Th/234U chronological control is provided by previously reported radiocarbon and Th/U TIMS measurements (Fairbanks 1989; 1990; Bard et al., 1993), supplemented by additional measurements (Fairbanks et al., in prep.). The majority of samples through the deglaciation have been dated with both techniques. M. annularis specimens older than 15.7 14C kyrs have yet to be Th/U dated. Absolute ages for these specimens are interpolated using a least squares regression through the appropriate coral data (Fairbanks et al., in prep.). Ice volume residual Dd18O is calculated in a similar fashion to Guilderson et al., (1994). In specimens older than the last glacial maximum as determined by the A. palmata Barbados sea level record, the residual is calculated using an ice volume component of 1.1”.