Search results for "500 Naturwissenschaften und Mathematik::550 Geowissenschaften"
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Widening of Hydrous Shear Zones During Incipient Eclogitization of Metastable Dry and Rigid Lower Crust—Holsnøy, Western Norway
2021
The partially eclogitized crustal rocks on Holsnøy in the Bergen Arcs, Norway, indicate that eclogitization is caused by the interplay of brittle and ductile deformation promoted by fluid infiltration and fluid‐rock interaction. Eclogitization generated an interconnected network of millimeter‐to‐kilometer‐wide hydrous eclogite‐facies shear zones, which presumably caused transient weakening of the mechanically strong lower crust. To decipher the development of those networks, we combine detailed lithological and structural mapping of two key outcrops with numerical modeling. Both outcrops are largely composed of preserved granulite with minor eclogite‐facies shear zones, thus representing th…
Polyester microplastic fibers affect soil physical properties and erosion as a function of soil type
2021
Microplastics are recognized as a factor of global change contaminating many environmental compartments. Agricultural soils are very likely to receive microplastic contamination and are of particular concern due to their role in food production. Microplastic fibers have already been shown to be able to affect soil properties, but their effect on different soil types is poorly understood. Moreover, limited information is available on how the presence of this pollutant can affect soil water erosion processes, which are extremely important issues in many environments. In the light of this, we performed two experiments (carried out on a microscale) to investigate how the presence of polyester m…
Fracture Shape and Orientation Contributions to P-Wave Velocity and Anisotropy of Alpine Fault Mylonites
2021
P-wave anisotropy is significant in the mylonitic Alpine Fault shear zone. Mineral- and texture-induced anisotropy are dominant in these rocks but further complicated by the presence of fractures. Electron back-scattered diffraction and synchrotron X-ray microtomography (micro-CT) data are acquired on exhumed schist, protomylonite, mylonite and ultramylonite samples to quantify mineral phases, crystal preferred orientations, microfractures and porosity. The samples are composed of quartz, plagioclase, mica and accessory garnet, and contain 3-5% porosity. Based on the micro-CT data, the representative pore shape has an aspect ratio of 5:2:1. Two numerical models are compared to calculate the…