Barbados Coral Oxygen Isotope Data: Readme file
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                   NOAA Paleoclimatology Program
                               and
            World Data Center for Paleoclimatology, Boulder
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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, ~ 13N 60W
					
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 (100-200g) were reacted at 90C 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.