The correlation potential of magnetic susceptibility and outcrop gamma-ray logs at Tournaisian-Viséan boundary sections in western Europe

We have measured five deep-water carbonate and carbonate-siliciclastic sections at the Tournaisian-Visean (Tn/V) boundary in western Europe, using petrophysical outcrop logging techniques (gamma-ray spectrometry /GRS/ and magnetic susceptibility /MS/). The aim was to trace correlatable log patterns across the flanks of the London-Brabant Massif from eastern Ireland to western Germany. Both GRS and MS logging proved useful for long-distance (up to similar to 1000 km) correlation. The log patterns can be interpreted in terms of sea-level fluctuations. A late Tournaisian regression, a sequence boundary at the Tn/V boundary, early Visean lowstand systems tract and an overlying transgressive to regressive succession can be identified from the GRS and MS logs. The Tn/V sequence boundary can be correlated with exposure features and karstic surfaces in the up-dip shallow-water settings at the boundary between sequence 4 and 5 of Hance et al. (2001, 2002). This indicates that sea-level fluctuations around the Tn/V boundary were synchronous and traceable on the flanks of the London-Brabant Massif. The GRS-based logging has a greater correlation potential than MS as it can be applied in a broad spectrum of facies and depositional settings. In certain sections, the MS signal shows an increasing trend during transgression and a decreasing during regression, which is opposite to the MS paradigm from shallow-water carbonate platform settings. These trends are assumed to result from landward/basinward facies shifts of low-productivity carbonate ramp systems. Lowstand shedding of carbonate tempestites and turbidites results in low MS values while during sea-level rise the ramp systems backstep, developing retrograding facies successions in their distal parts, which are associated with upward-increasing MS values

Data for: Million-year secular variations in the elemental geochemistry of Devonian marine records and a link to global climate and bioevents; Prague Basin, Czech Republic

A complete geochemical dataset including ICP-MS (inductively-coupled plasma mass spectrometry) data, TOC (total organic carbon) data, EDXRF (energy-dispersive X-ray fluorescence) data and a data file with calibration equations based on cross-correlation of ICP-MS and EDXRF data, along with section and sample identification and assignment to lithostratigraphic units indicated in the text, tables and figures

Data for: Reservoir deltas and their role in pollutant distribution in valley-type dam reservoirs: Les Království Dam, Elbe River, Czech Republic

Sediment grain size data, EDXRF geochemical data, ICP-MS data, ICP-OES data, PAH concentrations, gamma-ray spectrometric data including 137Cs mass activities and a set of 30 ground-penetration radar profile

Data for: Million-year secular variations in the elemental geochemistry of Devonian marine records and a link to global climate and bioevents; Prague Basin, Czech Republic

A complete geochemical dataset including ICP-MS (inductively-coupled plasma mass spectrometry) data, TOC (total organic carbon) data, EDXRF (energy-dispersive X-ray fluorescence) data and a data file with calibration equations based on cross-correlation of ICP-MS and EDXRF data, along with section and sample identification and assignment to lithostratigraphic units indicated in the text, tables and figures.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Data for: Reservoir deltas and their role in pollutant distribution in valley-type dam reservoirs: Les Království Dam, Elbe River, Czech Republic

Sediment grain size data, EDXRF geochemical data, ICP-MS data, ICP-OES data, PAH concentrations, gamma-ray spectrometric data including 137Cs mass activities and a set of 30 ground-penetration radar profilesTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

The Pragian in the Prague Synform: Questions, Duration and Global correlation.

peer reviewe

Human impact on fluvial sediments: how to distinguish regional and local sources of heavy metals contamination

Regional contamination of southern Moravia (SE part of the Czech Republic) by heavy metals and magnetic particles during the 20th century was quantified in fluvial sediments of the Morava River. The influence of local sources to the regional contamination of the river sediments and impact of sampling sites heterogeneity were studied in profiles with different sedimentology (facies) and lithology. For this purpose, hundreds of samples were obtained from regulated channel banks and naturally inundated floodplains and proxy elementary analyses have been carried out by X-ray fluorescence spectroscopy (ED XRF), further calibrated by ICP MS. Magnetic susceptibility as a proxy of industrial contamination was determined and the age model has been obtained by 210Pb dating method. After establishing the lithological background from floodplain profiles, assessment of heavy metal contamination was done by using enrichment factors (EFs) of heavy metals (Pb, Zn, Cu, Cr) and magnetic susceptibility. Floodplain sedimentary profiles were found to be realiable for assessment of contamination and reconstruction of large scale, i.e. a really averaged regional contamination, while regulated channel banks are suitable for obtaining of more or less qualitative information of influence of local point sources in the area because sediments from regulated river banks qualitatively reflect the actual local contamination of the river system. It allowed us to distinguish the influence of local sources of contamination by comparing with more spatially averaged contamination signal from more distal floodplain profiles. The study area is rather weakly contaminated (EF ∼ 1-2), while individual sediment strata from regulated channel banks contains several times larger concentrations of heavy metals