A geochemical application of the ITRAX scanner to a sediment core containing eastern Mediterranean sapropel units
- 1 January 2006
- journal article
- Published by Geological Society of London in Geological Society, London, Special Publications
- Vol. 267 (1), 65-77
- https://doi.org/10.1144/gsl.sp.2006.267.01.05
Abstract
The ITRAX micro-X-ray fluoresence (XRF) core scanner has been applied in a sediment geochemistry investigation. The core sections selected contain examples of the organic-rich sedimentary units (sapropels) that form periodically in the eastern Mediterranean basin. Sapropels are visually obvious from their dark coloration, but the ITRAX X-radiograph also reveals physical property changes that result mainly from the high pore-water content of sapropels. A consideration of wavelength-dispersive XRF data from discrete samples of the most recent sapropel (S1) was made along with the set of elements reported by the ITRAX instrument’s energy-dispersive XRF system over core sections containing S1. This allowed selection of a suite of eight inter-element ratios or element integrals through which characteristic features of sapropel development and geochemistry were revealed. While recognizing that the measured XRF element integrals from the ITRAX do not have an exact constant relationship with element concentration over changing sediment types, this combination of ratios provides significant information for geochemical interpretation. These include evidence for: (i) the presence of high Corg contents in the visual sapropel from Ba/Ti and Br/Cl ratios; (ii) a thinning of the original sapropel thickness by post-depositional oxidation from Mn/Ti and Cu/Ti ratios; (iii) pyrite authigenesis in the residual visual sapropel from Fe/Ti and S/Cl ratios and the As integral; and (iv) aragonite formation in and around the sapropel from the Sr/Ca ratio. These same ratios were then used to interpret ITRAX data from a deeper section of the same core containing the older sapropel S3, where the same characteristics, including the relict post-depositional oxidative thinning of the original unit, could be identified with only minor differences of detail. Directions of supply of Fe, As and Cu into the sapropels could be inferred from profile shapesKeywords
This publication has 48 references indexed in Scilit:
- ITRAX: description and evaluation of a new multi-function X-ray core scannerGeological Society, London, Special Publications, 2006
- Florisphaera profunda and the origin and diagenesis of carbonate phases in eastern Mediterranean sapropel unitsPaleoceanography and Paleoclimatology, 2004
- A dynamic concept for eastern Mediterranean circulation and oxygenation during sapropel formationPalaeogeography, Palaeoclimatology, Palaeoecology, 2003
- Geological constraints on tidal dissipation and dynamical ellipticity of the Earth over the past three million yearsNature, 2001
- On the late Pleistocene‐Holocene sapropel record of climatic and oceanographic variability in the eastern MediterraneanPaleoceanography and Paleoclimatology, 2001
- Duration of S1, the most recent sapropel in the eastern Mediterranean Sea, as indicated by accelerator mass spectrometry radiocarbon and geochemical evidencePaleoceanography and Paleoclimatology, 2000
- Chemical cycles in Pliocene sapropel-bearing and sapropel-barren eastern Mediterranean sedimentsPalaeogeography, Palaeoclimatology, Palaeoecology, 2000
- Geochemical and paleomagnetic evidence for the occurrence of “missing” sapropels in eastern Mediterranean sedimentsPaleoceanography and Paleoclimatology, 1997
- Active post-depositional oxidation of the most recent sapropel (S1) in sediments of the eastern Mediterranean SeaGeochimica et Cosmochimica Acta, 1996
- Evaluation of the Plio‐Pleistocene astronomical timescalePaleoceanography and Paleoclimatology, 1996