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XRF core-scanning data of composite sediment core ROD11 from the crater basin of Rodderberg, Germany

XRF core-scanning data characterizes the sediment composition geochemically and supports palaeoclimatic reconstruction of glacial/interglacial cycles for the Middle Pleistocene sediment record from the crater basin of Rodderberg, Germany. A 72.8 m long sediment record was recovered by means of wire-line drilling with 3 m long liners from the silted-up crater basin of Rodderberg (East Eifel Volcanic Field) in the vicinity of the city of Bonn, Germany. The composite record ROD11 was subjected to XRF core scanning with a spatial resolution of 2 mm using an ITRAX XRF core scanner, Cox Analytics with a Molybdenum X-ray tube (Croudace et al., 2019; Croudace and Rothwell, 2015). The measurements were conducted with a fixed setting of 30 kV, 40 mA, and an exposure time of 5 s. The software Q-spec (Cox Analytics) was employed for processing of the scanner output and calculation of qualitative elemental measurements in counts. Principal component analysis was then employed to reduce the data dimension and identify latent environmental control factors for the reliable set of elemental data in the normalized (clr-transformed) and standardized XRF dataset (Bertrand et al., 2024). Valued by multiple dating techniques for the past 430 ka, this terrestrial record provides an environmental reconstruction since the Middle Pleistocene.

Bulk geochemistry of composite sediment core ROD11 from the crater basin of Rodderberg, Germany

Bulk geochemistry characterizes sediment composition and supports palaeoclimatic reconstruction of glacial/interglacial cycles for the Middle Pleistocene sediment record from the crater basin of Rodderberg, Germany. A sediment record measuring 72.8 m in length was retrieved by employing wire-line drilling techniques, utilising 3 m-long liners, from the silted-up crater basin of Rodderberg (East Eifel Volcanic Field) in the vicinity of the city of Bonn, Germany. The composite record ROD11 was subjected to continuous analysis for bulk geochemistry (total carbon, total nitrogen, total sulphur) with 10 cm spatial resolution employing a CNS analyser (EuroEA, Eurovector). Additionally, the analysis of total organic carbon was carried out with the same setup but after the destruction of carbonates with 3% and 20% sulphuric acid. The difference between total carbon and total organic carbon yields total inorganic carbon, a proxy parameter for carbonates. The calculation of organic matter was performed by multiplication of total organic carbon with a value of 2.13, in accordance with the methodology proposed by Dean (1974). The calculation of carbonaceous matter was accomplished by multiplying total inorganic carbon values with 8.33, in order to account for the stoichiometric mass change from C to CaCO3. Minerogenic matter was determined as the difference between 100 and the sum of organic matter and carbonaceous matter. These parameters enhance the palaeoclimatic interpretation for the past 430 ka. Valued by multiple dating techniques, this terrestrial record provides an environmental reconstruction since the Middle Pleistocene.

Biogenic silica of composite sediment core ROD11 from the crater basin of Rodderberg, Germany

Biogenic silica data characterize lacustrine sediments and support the palaeoclimatic interpretation of interglacials for the Middle Pleistocene sediment record from the crater basin of Rodderberg, Germany A 72.8 m long sediment record was recovered by means of wire-line drilling with 3 m long liners from the silted-up crater basin of Rodderberg (East Eifel Volcanic Field) in the vicinity of the city of Bonn, Germany. The composite record ROD11 was analysed for the presence of biogenic silica, with a 20 cm spatial resolution for interglacial periods and a 100 cm spatial resolution for glacial periods. The investigations were conducted using automated leaching in a continuous flow system (Müller and Schneider, 1993). The extraction of biogenic silica was performed with 1 M NaOH solution at a temperature of 85 °C. The presence of dissolved biogenic silica was detected through spectrophotometric analysis. This parameter serves as a proxy for the presence of diatoms in the sediment record and indicates the depositional conditions in a lake and its trophic state. This proxy parameter enhances the interpretation of organic matter, which is not only of lacustrine origin but can also be contributed by in wash of terrestrial plant remains, and the palaeoclimatic interpretation over the past 430 ka. The terrestrial record from Rodderberg is of significant value, as it can be dated using multiple techniques and provides a reconstruction of the environment since the Middle Pleistocene.

Magnetic susceptibility of composite sediment core ROD11 from the crater basin of Rodderberg, Germany

Magnetic susceptibility – a proxy parameter for core correlation and reconstruction of glacial/interglacial cycles for the Middle Pleistocene sediment record from the crater basin of Rodderberg, Germany. A 72.8 m long sediment record was recovered by means of wire-line drilling with 3 m long liners from the silted-up crater basin of Rodderberg (East Eifel Volcanic Field) in the vicinity of the city of Bonn, Germany. The two drill holes (ROD11-2 and ROD11-3) were merged to establish a composite record (ROD11) based on macroscopic sediment description and were fine-tuned by magnetic susceptibility data. Magnetic susceptibility was continuously logged with 1 cm spatial resolution with a Bartington loop-sensor (MS2C) on a GEOTEK multi-sensor core-logger. Furthermore, this parameter facilitates the differentiation between glacial and interglacial sediments, thereby supporting the palaeoclimatic interpretation based on geochemical data spanning the past 430 ka. The combined evidence suggests a depositional evolution from a deep crater lake via a shallow lake or desiccating wetland followed by deposition of loess and pedogenesis. This terrestrial record, evaluated through multiple dating techniques, offers a comprehensive environmental reconstruction since the Middle Pleistocene.

Grainsize composition of composite sediment core ROD11 from the crater basin of Rodderberg, Germany

Grainsize data supports palaeoclimatic reconstruction of glacial/interglacial cycles for the Middle Pleistocene sediment record from the crater basin of Rodderberg, Germany. A sediment record measuring 72.8 m in length was retrieved by employing wire-line drilling techniques, utilising 3 m-long liners, from the silted-up crater basin of Rodderberg (East Eifel Volcanic Field) in the vicinity of the city of Bonn, Germany. For the purpose of grainsize analysis, the composite record ROD11 was systematically subsampled at a spatial resolution of 2 cm and examined through a laser diffraction particle size analyser (Beckman Coulter LS 13320). The resulting sedimentological data characterise glacials as silt-dominated (aeolian sediments: loess), interglacials as sand-dominated (runoff-related deposits from the step crater walls) and clay dominance for the Holocene soil. The terrestrial sediment record has been evaluated through multiple dating techniques and it provides a comprehensive environmental reconstruction since the Middle Pleistocene, thus providing valuable insights into the region's climate history.

Reprocessed deep seismic reflection profile DEKORP 1-Laacher See Experiment 8701 across the Laacher See Volcano, East Eifel, Germany

The deep seismic reflection survey DEKORP 1-Laacher See was conducted as additional measurements in the Laacher See area in 1987 as part of the DEKORP-1 project, one main traverse of the German continental seismic reflection program. This small survey was an attempt to reveal the 3-D crustal structure in an area of the Quaternary East Eifel Volcanism and possibly find some magma chambers in the crust with high-fold near-vertical incidence vibroseis acquisition (DEKORP Research Group, 1991). The measurement consists of a 8,64 km long, multifold 2D seismic line 8701 across the Laacher See in NE-SW direction and two pseudo-3D seismic areas 8702 north of the lake and 8703 beneath the lake with one-fold coverage in each case. Laacher See or Lake Laach is a caldera lake in the Rhineland-Palatinate, Germany, one of the volcanic centres of the East Eifel Volcanic Field. It belongs together with the West Eifel to the youngest volcanic areas in Central Europe. The caldera of the Laacher See was formed about 12 900 years ago after the volcano explosively erupted, and the remaining crust collapsed into the empty magma chamber below. The Laacher See is still considered to be an active volcano, proven by seismic activities and thermal anomalies under the lake. The first processing of the Laacher See data was carried out at the Geophysical Institute of the CAU University Kiel in 1990. Unfortunately, these results have not been preserved or published. According to DEKORP Research Group (1991) the first processing resulted in poor data quality caused by high scattering and attenuation in the volcanic material near the surface. This reflected energy was not enough to image a magma chamber beneath the lake or any other structures. Thus, information about the structure of the Earth’s crust of the Eifel is mainly based on the deep seismic reflexion profile DEKORP 1B, running ca. 25 km to the west from the Laacher See und crossing DEKORP 1A at its northern profile end. In recent years, deep low‐frequency (DLF) earthquakes have been detected in the Laacher See area indicating ongoing magmatic activity in the lower crust and upper mantle (Hensch et al., 2019, Dahm et al. 2020). These and other signatures suggested the reprocessing of the Laacher See data with modern methods. Thus, the 2D seismic line 8701 has been reprocessed in 2020 within the framework of the Master’s thesis by Agafonova (2020) written at the Technical University of Berlin and supervised by the GFZ Potsdam. All reprocessed data come in SEGY trace format, the final sections additionally in PNG or PDF graphic format: as raw FF-sorted unstacked data, as preprocessed CDP-/FF-sorted unstacked data as well as poststack-time/-depth unmigrated and migrated sections. Moreover, the results of the tomographic inversion are included. Detailed information about acquisition and reprocessing parameters of line 8701 can be found in the accompanying Technical Report (Agafonova & Stiller, 2021). The reprocessed results of the Laacher See survey 1987 can be of importance for better understanding the structure of the Eifel crust. Even though significant knowledge gaps and uncertainties exist due to the insufficient data quality, such important questions can already be discussed as: • How complex is the structure beneath the Laacher See? • Can the Mantle-Crust Boundary be defined at ca. 34 km depth? • Are the strongly inclined events in the Upper Crust between 1-5 km depth parts of caldera ring-faults? • Do the reflections between 5-7 km depth indicate boundaries of a possible magma chamber?

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