STED nanoscopy - A novel way to image the pore space of geological materials.

STED nanoscopy (Stimulated Emission Depletion). which can resolve details far below the diffraction barrier has been applied hitherto preferentially to life sciences. The method is however also ideal for the investigation of geological matrices containing transparent minerals, an application tested here, to our knowledge, for the first time.

Radon emanation from fresh, altered and disturbed granitic rock characterized by C-PMMA impregnation and autoradiography.

Radon emanation from intact samples of fresh ("BG"), altered ("Fract") and disturbed ("EDZ") Finnish granitic rock from Kuru (Finland) and its dependence on humidity and rock structural factors was studied. The pore network of the rock was characterized by microscopy and impregnation with C-PMMA (polymethylmethacrylate) resin and autoradiography. The radon emanation factor was increasing linearly with the relative humidity.

Multidisciplinary analysis of Finnish esker sediment in radon source identification.

In order to define the naturally-occurring radioactive materials that are the source of radon in natural environments, a comprehensive analytical (geochemical, physical and chemical) methodology was employed to study sand samples from the Hollola esker in the city of Hollola (Lahti area, Finland). Techniques such as gamma-spectrometry, emanation measurements, sequential chemical extraction, scanning electron microscopy (SEM), electron probe microanalyses (EPMA) and inductively-coupled plasma mass spectrometry (ICP-MS) were used to determine the potential source of radon. Monazite and xenotime, uranium- and thorium-bearing minerals and potential radon sources, occurred in significant amounts in the samples and were also the main reason for the distribution of uranium and thereby radium in separate grain-size fractions.

Interpretation of out-diffusion experiments on crystalline rocks using random walk modeling.

Matrix diffusion in saturated rocks with very low permeability is one of the major mechanisms of solute transport. Laboratory out-diffusion experiments on rock samples may provide an estimate of the bulk diffusion coefficient. However, numerous results have shown that this average parameter does not really depict the complex mechanism of diffusion as a function of the internal heterogeneity of crystalline rocks.