Mineralogy, geochemistry and elemental ratios of ODP Core 171B-1049C-8X

Inorganic geochemistry and mineralogy of Core 171B-1049C-8X, containing a Cretaceous/Tertiary boundary section, was investigated by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The ages of samples analyzed stretched from the latest Maastrichtian into the Danian. XRD measurements were made using the peak height method. A reduction in low-magnesium calcite and an increase in quartz were found above the spherule layer. Substantial amounts of dolomite were noted just above the spherule layer. XRF analyses were performed using the RHSMALL program to measure the abundance of major and minor elements. Replicate analyses for each technique were performed to assess the precision of the results. The section above the spherule bed was found to be characterized by peaks in many elements, including Si, Al, Fe, and Mg, as well as the following elemental ratios: Fe/Al, Ni/Al, Zr/Rb, and Rb/Sr'. Above the spherule bed, there were significant reductions in Ca, Sr/Ca, Ti/Al, K/Al, Rb/Al, Cr/Al, Ba/Al, biogenic Ba, and excess P.