Search results for "550 Geowissenschaften"
showing 10 items of 31 documents
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…
Enhanced sulfur in the upper troposphere and lower stratosphere in spring 2020
2022
Sulfur compounds in the upper troposphere and lower stratosphere (UTLS) impact the atmosphere radiation budget, either directly as particles or indirectly as precursor gas for new particle formation. In situ measurements in the UTLS are rare but are important to better understand the impact of the sulfur budget on climate. The BLUESKY mission in May and June 2020 explored an unprecedented situation. (1) The UTLS experienced extraordinary dry conditions in spring 2020 over Europe, in comparison to previous years, and (2) the first lockdown of the COVID-19 pandemic caused major emission reductions from industry, ground, and airborne transportation. With the two research aircraft HALO and Falc…
Fluvial activity of the late-glacial to Holocene “Bergstraßenneckar” in the Upper Rhine Graben near Heidelberg, Germany – first results
2022
Abstract. The term “Bergstraßenneckar” (BSN) refers to an abandoned course of the river Neckar. It flowed in a northern direction east of the river Rhine in the eastern part of the northern Upper Rhine Graben in southwestern Germany. The former meandering course merged with the Rhine ca. 50 km further north of the site of the present-day confluence near Mannheim. The palaeo-channels are still traceable by their depressional topography, in satellite images and by the curved boundaries of adjacent settlements and land parcels. In the plan view, satellite and aerial images reveal a succession of meander bends, with older bends being cut off from younger channels. Based on stratigraphic investi…
Strontium and oxygen isotope analyses reveal Late Cretaceous shark teeth in iron age strata in the Southern Levant
2020
Carbonates from the ancient world's longest aqueduct:A testament of Byzantine water management
2021
The fourth‐ and fifth‐century aqueduct system of Constantinople is, at 426 km, the longest water supply line of the ancient world. Carbonate deposits in the aqueduct system provide an archive of both archaeological developments and palaeo‐environmental conditions during the depositional period. The 246‐km‐long aqueduct line from the fourth century used springs from a small aquifer, whereas a 180‐km‐long fifth‐century extension to the west tapped a larger aquifer. Although historical records testify at least 700 years of aqueduct activity, carbonate deposits in the aqueduct system display less than 27 years of operation. This implies that the entire system must have been cleaned of carbonate…
Freshwater pearl mussels from northern Sweden serve as long-term, high-resolution stream water isotope recorders
2019
The stable isotope composition of lacustrine sediments is routinely used to infer Late Holocene changes in precipitation over Scandinavia and, ultimately, atmospheric circulation dynamics in the North Atlantic realm. However, such archives only provide a low temporal resolution (ca. 15 years), precluding the ability to identify changes on inter-annual and quasi-decadal timescales. Here, we present a new, high-resolution reconstruction using shells of freshwater pearl mussels, Margaritifera margaritifera, from three streams in northern Sweden. We present seasonally to annually resolved, calendar-aligned stable oxygen and carbon isotope data from 10 specimens, covering the time interval from …
Polar motion prediction using the combination of SSA and Copula-based analysis
2018
The real-time estimation of polar motion (PM) is needed for the navigation of Earth satellite and interplanetary spacecraft. However, it is impossible to have real-time information due to the complexity of the measurement model and data processing. Various prediction methods have been developed. However, the accuracy of PM prediction is still not satisfactory even for a few days in the future. Therefore, new techniques or a combination of the existing methods need to be investigated for improving the accuracy of the predicted PM. There is a well-introduced method called Copula, and we want to combine it with singular spectrum analysis (SSA) method for PM prediction. In this study, first, we…
Quantification of volcano deformation caused by volatile accumulation and release
2022
<p>Magma stored in the crust may exsolve a significant amount of volatiles, primarily CO<sub>2</sub>, but also H<sub>2</sub>O and SO<sub>2</sub> if cooling promotes crystallisation and volatile exsolution. These volatiles may, over time, segregate and accumulate into a gas-rich foam at the roof of the magma body. This is the underpinning process to explain the frequently observed ‘excess gas’ produced in explosive eruptions, where the amount of erupted SO<sub>2</sub> is much larger than can be explained by the mass of erupted products and …