Paleoenvironmental assessment of a lower Jurassic succession in the NW-German Basin employing DRIFTS

Abstract

High-resolution reconstruction of paleoenvironmental conditions of sedimentation requires the qualitative and quantitative assessment of the major sediment-forming fractions, i.e., carbonate, clay, quartz and organic matter. Simultaneous determination of these sediment-forming fractions by cost-effective and rapid methodologies is difficult to achieve. Previously, either XRF-, XRD-, and microscopy-based methods, or combinations thereof have been employed, complemented by organic carbon analysis. We here present a simultaneous approximation of the most relevant sediment-forming constituents, carbonate, clay, and organic matter, as well as quartz and feldspar, if present in sufficient quantity, by Diffusive Infra-Red Fourier Transformation Spectroscopy (DRIFTS). The technique does not require elaborated sample preparation or large sample amounts and is conducted without analytical reagents, solvents or carrier gases, thereby allowing high sample through-put. As such, DRIFTS investigation is ideal for stratigraphically highly-resolved studies. We applied DRIFTS to a sediment succession of Pliensbachian/Toarcian age and differentiated six sedimentary facies intervals that previously had been established based on application of more sophisticated but also more cost- and time-affording methodologies like XRF, XRD and programmed pyrolysis. While having been applied previously to characterization of soils and kerogen concentrates, we here demonstrate applicability of the DRIFTS technique to analysis of pre-Quaternary and consolidated sedimentary sequences.