This dataset provides mechanical test data for quartz sand (“MAM1ST-300”, Sibelco, Mol, Belgium), gypsum powder (plaster; “Goldband”, Knauf), kaolin clay powder, garnet sand, and mixtures of quartz sand and gypsum powder, used at the Analogue Laboratory of the Department of Geography at the Vrije Universiteit Brussel, Brussels, Belgium, for simulating brittle rocks in the upper crust (Poppe et al., 2019). The measured properties are density ρ, tensile strength T0, shear strength σ, obtained by density measurements, ring-shear tests (RST; at Helmholtz Centre Potsdam GFZ, Germany), direct shear tests, traction tests (at University of Maine, Le Mans, France) and extension tests. The obtained tensile strengths and shear strengths reconstruct two-dimensional failure envelopes for each material. By fitting linear Coulomb and non-linear combined Griffith failure criteria to the characterised failure envelopes (Jaeger et al., 2007), the internal friction coefficient µC, Coulomb cohesion CC and Griffith cohesion CG are obtained. The influence of the material emplacement technique has been investigated in Poppe et al. (2021) to which this data set is supplementary, by repeat characterisation of the above physical parameters under three emplacement conditions, i.e. sieving, pouring (non-dried state) and compaction after pouring (oven-dried state).
We find that densities of the materials and mixtures range from ~1600 kg.m³ (sieved) and ~1700 kg.m³ (compacted) for pure quartz sand to ~600 kg.m³ (poured) to ~900 kg.m³ (compacted) for pure plaster. Tensile strengths range from ~166 Pa (sand) to ~425 Pa (plaster). Velocity ring-shear tests on a 90 wt% quartz sand – 10 wt% plaster mixture show a minor shear rate-weakening of <2% per ten-fold increase in shear velocity. The materials show a behavior ranging from Mohr-Coulomb behavior for the materials with coarser grain size (sands) to combined Griffith-Mohr-Coulomb behavior for the powder materials (plaster, kaolin), with the sand-plaster mixtures occupying a spectrum between both end-members. Peak friction coefficients range from ~0.5 (sand) to ~0.6 (plaster) with a maximum of ~0.9 (80:20 wt% sand:plaster), peak Coulomb cohesions range from 13 Pa (sand) to 248 Pa (plaster), peak Griffith cohesions range from ~10 Pa (sand) to ~425 Pa (plaster).
This dataset contains the paleomagnetic supplementary material to the article Kelder et al. (subm.), which presents a magnetostratigraphic correlation of Late Miocene lacustrine sediments based on multi-polarity greigite. The multi-polarity is visible in most thermal paleomagnetic results (Zijderveld diagrams) by antipodal high and medium temperature components, while only one magnetic component was visible in the alternating field demagnetization diagrams. Based on this complex behavior, a tailored demagnetization approach was developed to allow for reliable magnetostratigraphic dating of lacustrine sediments.
The dataset includes demagnetization data from four drill cores located nearby Paks, Hungary. They were not oriented, meaning that only the inclination could be used for paleomagnetism. The measurements took place at the Paleomagnetic Laboratory Fort Hoofddijk in Utrecht University, The Netherlands. For details about the methodology the reader is referred to the methodology in Kelder et al. (subm).
Three types of data are distinguished:
• Thermal demagnetization results (.th files)
• Alternating field demagnetization results (.af files).
• Interpreted magnetic vectors for demagnetization files (.dir files)
The .th, .af. and .dir files can be viewed with Notepad or similar programs, and analyzed via the Open Source platform Paleomagnetism.org (Koymans et al., 2016). The .dir files only exist for the cores PAET-30 and PAET-34, because these were interpreted in detail, while the material of the other cores (PAET-26, 27) were mainly used for rock magnetic purposes.
Finally, an overview of the data files, abbreviations and sample codes is provided in the data description file.