The application of high resolution X-ray computed tomography on naturally deformed rock salt: Multi-scale investigations of the structural inventory. (August 2015)

• Record Type: Journal Article
• Authors: Thiemeyer, Nicolas; Habersetzer, Jörg; Peinl, Mark; Zulauf, Gernold; Hammer, Jörg
• Is Part Of: Journal of structural geology. Volume 77(2015:Aug.)
• Page Start: 92
• Page End: 106
• Publication Date: 2015-08
• Subjects: Computed tomography -- Rock salt -- Anhydrite -- Fluid inclusions -- Microstructures; Geology, Structural -- Periodicals; Géomorphologie structurale -- Périodiques; Geology, Structural; Periodicals; 551.805
• DOI: 10.1016/j.jsg.2015.05.014
• Languages: English
• ISSNs: 0191-8141

Abstract

Abstract: X-ray computed tomography (CT) represents a useful technique providing new perspectives and insights for the structural investigation of naturally-deformed rock salt. Several samples of Permian rock salt from Gorleben, Asse and Teutschenthal (Germany) were investigated by exploiting the non-destructive nature of μCT and nCT techniques particularly for salt rocks. CT imaging enabled the visualization and quantification of anhydrite impurities, pore space and fluid phases located along grain-boundaries or trapped as intracrystalline inclusions. Disseminated grains and aggregates of anhydrite in rock salt of the Gorleben salt dome have been visualized and quantified by μCT for the first time in order to portray their spatial occurrence. The visualization of anhydrite aggregates and pore space shows no correlation between their spatial distributions. This independence excludes the anhydrite to be responsible for elevated porosity (0.87 ± 0.07 vol.-%). High-resolution nCT scans (≤1 μm voxel size) of single intracrystalline and grain-boundary fluid inclusions from Gorleben and Asse rock salt allowed the visualization and quantification of their various phase components. A major achievement is the detailed description of the morphology and shape of the fluid inclusions and of their phase components, which has not been conducted in rock salt research by high-resolution X-ray CT imaging before. Highlights: Computed tomography was applied to naturally deformed rock salt for the first time. High resolution nano-CT scans on fluid inclusions were performed for the first time. Quantification and 3D visualization of minerals, porosity and fluids are presented. CT reveals elevated porosity not to be dependent on the distribution of anhydrite.