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Marine Geology Data

Carbonate Data from LDEO & Brown University

NGDC Data Sets G00998 & G01021



This data set contains calcium carbonate percentage data from marine sediment cores, plus C14 dates or age models as available. Display software is available from the WDC-A Paleoclimatology via anonymous ftp.

Analyses were done for the CLIMAP project, and for numerous regional studies. On average, the cores span 100,000 to 200,000 years, sampled at intervals averaging 3,000 to 10,000 years. Numerous cores span only the last deglaciation, while a few cover intervals up to 3,000,000 years. Samples analyzed consisted of either bulk sediment, or fine-fraction sediment passed through either a 63 or 74 micron sieve. There is no significant difference in analyses based on these two fine fractions, and the sieve size is not recorded in the files. There is also little difference between fine and total fraction analyses, but the two types are distinguished by file extension.

C14 ages for the LDEO data are in the LDEO C14 data set. Age models for the Farrell data are found in Tables 1-3, and in the respective data files.


LDEO Carbonate data were compiled under the direction of A. Esmay and W.F. Ruddiman at the Lamont-Doherty Earth Observatory of Columbia University. Data include CaCO3 percentages by interval down core for 328 sediments cores, principally from the Atlantic ocean.

Data are derived primarily from two sources. First, cores analyzed during the CLIMAP project to generate stratigraphic control on cores from key deep-sea regions. Second, cores analyzed using almost entirely National Science Foundation funds, but through smaller grants to individuals and institutions.

On average, cores span intervals of time of 100,000 to 200,000 years and have been analyzed at time steps of a few thousand years. Several cores span only the last deglaciation; a few cores cover much longer intervals, up to 3 million years. Samples are annotated as either bulk sediment, or fine-fraction (less than 63 or 74 micron) subsets. Station information is included.


Weight percentages of calcium carbonate in the Brown file were compiled by J. Farrell and W. L. Prell of Brown University for 17 equatorial Pacific Ocean sediment cores. Cores are identified by cruise and core id. Depth-in-core information and estimates of sediment age, by depth, in millions of years (Ma) are included. Carbonate percentages are weight percent of bulk samples, rounded to the nearest integer. Models used to generate (by linear interpolation) ages also included in table form. Ages are based primarily on paleomagnetic stratigraphy, refined by oxygen isotope stratigraphy, and correlation of CaCO3 events among cores, and range from 0 to 4 million years.

Comments on biostratigraphy, delta oxygen 18, calcium carbonate events, and core quality are also included on age model tables.


NGDC/WDC GMG, Boulder archives a wide variety of digital marine geology data collections, paper reports, microfilm, etc. containing sediment and hardrock data. Many of the digital files are available for direct download. Sample-by-sample inventory information for all data, regardless of format available from NGDC are fully searchable through the marine geology inventory (GEOLIN).