Holocene Variations in Subtropical Atlantic Sea-Surface Temperatures: 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: Holocene Variations in Subtropical Atlantic SST
LAST UPDATE: 7/2001 (Original Receipt by WDCA Paleo)  
CONTRIBUTORS: Peter deMenocal, Tom Guilderson, Joe Ortiz, Michael Sarnthein

IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2001-054

SUGGESTED DATA CITATION: deMenocal, P.B., et al., 2001,
Holocene Variations in Subtropical Atlantic SST. 
IGBP PAGES/World Data Center A for Paleoclimatology 
Data Contribution Series #2001-054. 
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. 

ORIGINAL REFERENCE: 
deMenocal, P.B., J. Ortiz, T. Guilderson, and M. Sarnthein, 2000,
Coherent High- and Low-Latitude Climate Variability During the 
Holocene Warm Period, Science, 288 (5474), 2198-2202.

FUNDING SOURCE: National Science Foundation, MG&G, USA

GEOGRAPHIC REGION: Subtropical Atlantic Ocean 
PERIOD OF RECORD: 23 - 0 KYrBP 

LIST OF FILES: Readme_deMenocal2000.txt (this file), 
658_sst.txt  (tab-delimited ASCII format).


DESCRIPTION:
Holocene SST variations at Site 658C were reconstructed using planktonic 
foraminiferal assemblage data.  Counts of 29 species were converted to warm 
and cold season SSTs using the F13' transfer function as presented in 
W. F. Ruddiman and L. K. Glover, Quat. Res. 5, 361-389 (1975). 
Average temporal resolution of the SST data ranges between ca. 50-100 years. 
Warm and cold season SST anomalies relative to coretop values and the 
warm-cold season SST seasonality were also computed.  

Variable: sample depth (cm), sample age (yrs BP), 
Planktonic foraminiferal assemblage sea surface temperature estimates 
(SSTwarm, SSTcold, SSTwarm anomaly, SSTcold anomaly, SST seasonality)
Variable unit: degrees centigrade
Data precision: SSTwarm= ±1.6°C, SSTcold=±1.3°C


Ocean Drilling Program Site 658, Hole C. 
Ocean Drilling Program Hole 658C was cored off Cap Blanc, Mauritania 
(20°45'N, 18°35'W, (GPS), 2263m) during ODP Leg 108. 
Sediment accumulation rates are high at this site (22 cm/kyr average) due, 
in part, to the dual influences of high regional surface ocean productivity 
and high supply of windblown African mineral dust. Strong seasonal upwelling 
and high productivity results from the strong northeast Trade winds which 
parallel the Northwest African margin. Hole 658C is also positioned within 
the axis of the summer African eolian dust plume which transports Saharan 
mineral aerosol dust to the adjacent subtropical Atlantic ocean. 
The site lies within an oceanographic boundary separating cooler temperate 
and subpolar waters to the north from warmer tropical water masses to the 
south and west.


Core 1H from Hole 658C was continuously subsampled at 2 cm intervals 
which is equivalent to between 50-100 years temporal resolution. 
Samples were analyzed for calcium carbonate and biogenic opal percentages, 
and the residual terrigenous (eolian) fraction was computed by difference. 
Planktonic foraminiferal assemblage census counts were then conducted on 
prepared samples (14). Warm and cold season SST estimates were calculated 
from the census count data using the F13' transfer function derived from 
faunal analysis of 191 Atlantic core tops 
(Ruddiman and Glover, Quat. Res. 5, 361-389 1975). 
Standard errors of estimate for the F13'-derived warm and cold season SSTs 
are 1.6°C and 1.3°C, respectively. At Hole 658C, the coretop (0-2cm) warm 
and cold season foraminiferal SST estimates (16.8°C and 25.8°C) agree within 
the error of estimate with the observed annual SST range at this location 
(18°C and 24°C, respectively).


Age control was established using 31 accelerator mass spectrometer (AMS) 
radiocarbon dates of monospecific samples of planktonic foraminifera 
(Globigerina bulloides or Globorotalia inflata) spanning the last 24,000 
calendar years BP. Raw radiocarbon dates were converted to calibrated 
calendar ages after applying a -500±50 year reservoir correction. 
The resulting age-depth profile indicates that sedimentation was continuous 
at a rate of 22 cm/ka spanning the last ca. 14 cal. ka BP. 
However, a brief hiatus between 328-324 cm (17.4-14.3 cal. ka BP) 
is indicated by several closely spaced dates (19).

Date of data generation: 1998-2000