(Table T1) Calcium carbonate content of sediments from ODP Leg 172 sites

Visual-domain diffuse reflectance data collected aboard the JOIDES Resolution with the Minolta spectrometer CM-2002 during Ocean Drilling Program Leg 172 have been used to estimate successfully the carbonate content of sediments. Calibration equations were developed for each site and for each lithostratigraphic unit (or subunit at Site 1063) using multiple linear regression on raw as well as pretreated reflectance spectra (i.e., first-order derivation and squaring of raw reflectance spectra) for a total of 4141 direct carbonate measurements. The root-mean-square errors of 4% to 7% are within the range of previous estimates using diffuse reflectance data and are acceptable for the general extensive range of carbonate contents (i.e., 0-70 wt%) that characterize sedimentation at Leg 172 sites.

Calcium carbonate and organic carbon at DSDP Leg 62 Holes

Percent CaCO3 was determined in selected samples aboard the ship by the carbonate-bomb technique (Müller and Gastner, 1971). Results of these analyses are listed in Table 1 and plotted in Figures 1, 3, 4, and 5 as plus signs (+). Samples collected specifically for analyses of CaCO3 and organic carbon were analyzed at three shore-based laboratories. Concentrations of total carbon, organic carbon, and CaCO3 were determined in some samples at the DSDP sediment laboratory, using a Leco carbon analyzer, by personnel of the U.S. Geological Survey, under the supervision of T. L. Valuer. Most of these samples were collected from lithologic units containing relatively high concentrations of organic carbon. Sample procedures are outlined in Boyce and Bode (1972). Precision and accuracy are both ±0.3% absolute for total carbon, ±0.06% absolute for organic carbon, and ±3% absolute for CaCO3.

Calcium carbonate mineralogy and stable isotopic composition of Leg 182 sites, Great Australian Bight

An intensive stable isotopic investigation was conducted on sediments recovered from the Great Australian Bight during Ocean Drilling Program Leg 182 at Sites 1127, 1129, and 1131. The sites comprise a transect from the shelf edge to upper slope through a thick sequence of predominately Quaternary cool-water carbonate sediments. Detailed mineralogic and stable isotopic (d18O and d13C) analyses of sediments from a total of 306 samples are presented from all three sites.

Calcium carbonate and trace element composition of ODP Leg 182 sites

An intensive geochemical investigation was conducted on carbonate sediments recovered during Ocean Drilling Program Leg 182. Four trace elements in 635 sediment samples from Sites 1126-1132 on the Great Australian Bight were examined by atomic absorption spectrometry on the acid-soluble fraction. Downhole profiles of these elements exhibit complicated fluctuations throughout the late Eocene to Pleistocene, principally because of the variations in the acid-soluble fraction. The purpose of this study is to present initial results on the geochemical composition of Cenozoic cool-water carbonates as a basis for a future detailed investigation to determine the paleoenvironment of a carbonate-dominated continental margin during the evolution of the Southern Ocean.

Sediment descriptions, stage, calcium carbonate, organic carbon, delta 13C and geolipids at DSDP Hole 93-603B

Organic matter contents of black shales from the Cretaceous Hatteras and Blake-Bahama formations have been compared to those from surrounding organic-poor strata using C/N ratios, d13C values, and distributions of extractable and nonsolvent-extractable, long-chain hydrocarbons, acids, and alcohols. The proportion of marine and land-derived organic matter varies considerably among all samples, although terrigenous components generally dominate. Most black shales are hydrocarbon-poor relative to their organic-carbon concentrations. Deposition of the black shales in Hole 603B evidently occurred through turbiditic relocation from shallower landward sites and rapid reburial at this outer continental rise location under generally oxygenated bottom-water conditions.

(Table 1) Calcium carbonate content of boulder clays sampled along the baltic coast of Schleswig-Holstein, Germany

The carbonate contents in the boulder clay ('Geschiebemergel') of abrasion cliffs were investigated along the Baltic coast of Schleswig-Holstein, northern West Germany. The calcareous boulder clay and stratified drift in the cliffs are interbedded with compressed thrust sheets of Cretaceous limestone, Tertiary Tarras clay, and Eemian clay. According to chemical analyses of 173 boulder clay samples, the amount of carbonate varies mostly between 6 and 17%. Owing to the small number of samples no definite conclusion could be drawn on the distribution of Danish Cretaceous limestones in the boulder clay, nor on the different directions of movement of Weichselian glaciers.