Precise major component determinations in deep-sea sediments using Fourier Transform Infrared Spectroscopy
Experiments using Fourier Transform Infrared Spectroscopy (FTIR) on a set of powdered deep-sea sediment samples show that it is an efficient method of quantifying the relative abundances of quartz, clay, and calcite. Ratios of absorption bands characteristic of different minerals are precise and reproducible to a relative error of about 1 % provided that samples are ground to <2 μm. FTIR results, calibrated to geochemical measurements, therefore offer a more rapid means of producing sedimentary time series data than do elemental or phase-specific extractions. Calibration of results to absolute amounts of sedimentary phases is possible for minerals with unique absorption bands. Highly IR-absorbant minerals such as quartz and calcite are quantitatively detectable in amounts as low as 5% in a mixture. In addition, FTIR measurements complement elemental analyses by allowing the accurate partitioning of elements, such as Si, which may occur in several phases.