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Crosshole seismic data at ICDP site 5068_1

This seismic crosshole dataset was acquired in the context of the DOVE project (Drilling Overdeep-ened Alpine Valleys) at ICDP site 5068_1 (Tannwald Basin) to image the glacial sediments at sub-meter scale. It consists of the field data with geographical coordinates. The project aims to investigate the landscape evolution in the Alpine region by drilling overdeep-ened valleys and analyzing the cores (DOVE-Phase 1 Scientific Team, Schaller et al., 2023, Schuster et al., 2024). At site 5068_1 (Tannwald Basin), three boreholes were drilled to a depth of about 160 m depth, reaching the bedrock. Boreholes 5068_1_A and 5068_1_B were flush drilling and bore-hole 5068_1_C was cored. In 2022, the boreholes were used to perform high-resolution crosshole seismic measurements in order to image the glacial sediments at sub-meter scale. This dataset con-sists of the seismic field data with geographical coordinates and is subdivided by (1) the used source and receiver borehole equipment (P: sparker and 24-station hydrophone string, SV: vertically polarizing shear wave source and three-component geophone string with eight geophones, SH: horizontally polarizing shear wave source and three-component geophone string with eight geophones), (2) the respective borehole plane (BA, BC, and AC), and (3) the acquisition geometry (STRING, CIRCLE, LINE_BA, LINE_BC, LINE_AC). The surface seismic data (CIRCLE, LINE_BA, LINE_BC, LINE_AC) was recorded by three-component geophones. The seismic data is provided in SEGY Rev. 1.0 format together with geometry files in csv-format.

Drilling Overdeepened Alpine Valleys (DOVE) - Operational Dataset of DOVE Phase 1

The overarching goal of the Drilling Overdeepened Alpine Valleys (DOVE) project will be to date the age and extent of past glaciations. Formerly-glaciated areas are often characterized by deeply incised structures, often filled by Quaternary deposits. These buried troughs and valleys were formed by glacial overdeepening, likely caused by pressurized subglacial meltwater below warm-based glaciers. Results of this drilling campaign, supported by new dating technologies, will further provide critical data on 'how' and 'at which rate' glacial erosion affects such mountain ranges and their foreland. These processes are also of fundamental importance for evaluating the safety of radioactive waste disposal sites, which are planned in areas of former glaciations. Moreover, results of this project will fill gaps in the knowledge of paleoclimate and atmospheric circulation patterns during past glacial epochs and how these patterns affected ice build-up. The operational data sets include the drill core documentation from the mobile Drilling Information System (mDIS), full round core scans, MSCL data sets, a preliminary core description and the geophysical downhole logging data that were acquired during and subsequent to the drilling operations. All downhole logs and core depth were subject to depth correction to a common depth master (cf. operational report for detailed information). The data are described by two scientific reports, the Operational Report (https://doi.org/10.48440/ICDP.5068.001) and the Explanatory Remarks on the Operational Datasets (https://doi.org/10.48440/ICDP.5068.002).

Climate model ensemble data for Neoproterozoic Snowball-Earth inceptions - placeholder

The Cryogenian period (720--635~million years ago) in the Neoproterozoic era featured two phases of global or near-global ice cover, termed `Snowball Earth'. Here we present a comprehensive sensitivity study considering different scenarios for the Cryogenian continental configuration, orbital geometry, and short-term volcanic cooling effects in a consistent model framework, using the climate model of intermediate complexity CLIMBER-3α. The continental configurations comprise palaeogeography reconstructions for both Snowball-Earth periods from two different sources, as well as two idealised configurations with either uniformly dispersed continents or a single polar supercontinent. Orbital geometries are sampled as multiple different combinations of the parameters obliquity, eccentricity, and argument of perihelion. For volcanic eruptions, we differentiate between single globally homogeneous perturbations, single zonally resolved perturbations, and random sequences of globally homogeneous perturbations with realistic statistics. The CO2 threshold lies between 10 and 250 ppm for all simulations.

Simulation data for tracing snowball bifurcation on an earth-like aquaplanet over 4 billion years

The atmospheric concentration of CO2 at which global glaciation (snowball) bifurcation occurs, changes throughout Earth's history, most notably because of the slowly increasing solar luminosity. Quantifying this critical CO2 concentration is not only interesting from a climate dynamics perspective, but also an important prerequisite for understanding past Snowball Earth episodes as well as the conditions for habitability on Earth and other planets. Here we use the coupled climate model CLIMBER-3α in an Aquaplanet configuration to scan for the Snowball bifurcation point for time slices spanning the last 4 billion years, thus quantifying the time evolution of the bifurcation and identifying a qualitative shift in critical state dynamics.

Stratigraphic and Multi Scanner Core Logging (MSCL) data plus supplementary luminescence dating material obtained from the scientific drilling QDR-RE-IfG and its drill site in the Aare Valley, Bern CH

The Quaternary Drilling at the Rehhag under the supervision of members of the Institut für Geologie (QDR-RE-IfG) was interested in the unconsolidated sediment infill of a bedrock trough in the Northern Alpine Foreland (NAF). Such bedrock troughs, now hidden beneath their sediment infill and/or in lakes, occur in formerly and currently glaciated areas, and are linked to increased glacial erosion. The base of these bedrock troughs is located beneath today's base level, which puts them beyond fluvial erosion, and this is why they are referred to as over-deepenings. Such overdeepenings can be found in the vicinity of the Alps which includes the NAF. After the formation or re-occupation of such overdeepenings by glacier ice these troughs provide accommodation space for the deposition of sediments. Hence, overdeepenings are likely to preserve sediments through glacial-interglacial cycles. As erosive agents, glaciers re-shape landscapes, and excavate and re-use sediments of previous glaciations which makes the preservation of intact sedimentary sequences through multiple glacial cycles unlikely. These repeated cut-and-fill cycles limit the Quaternary sedimentary record and make the investigation of the number and chronology of Quaternary glacial-interglacial cycles difficult. Overdeepenings, however, can preserve fractionated and probably intact sedimentary sequences throughout multiple glaciations. Hence, accessing the sediment infill of overdeepened bedrock troughs through core drillings provides insight into phases of the Quaternary at locations where formerly little information was available. To gain new insight into the Mid- to Late-Pleistocene sedimentary record in the Bern area (Switzerland) the drilling QDR-RE-IfG was conducted in Bern-Bümpliz, where a minor branch of the Aare Valley overdeepening is located in which Quaternary sediments at least 150 ka in age were expected. In Bern-Bümpliz, at the Rehhag, the uppermost 30 m of the sedimentary succession are accessible in an abandoned clay pit. The drilling reached 211.5 m driller's depth, recovering 208.5 m of unconsolidated sediment and, below a sharp contact, 3 m of Miocene Molasse bedrock. The recovery of intact core from unconsolidated sediment is challenging. Nevertheless, 92.3% of the core material was recovered in 1 m-long plastic liners in pristine condition. As the drilling reached the bedrock it is the first scientific drilling that recovered the full sedimentary suite in a part of the Aare Valley overdeepening. Within the sedimentary succession two sequences (A = lower, B = upper) were identified. Each of the sequences is initiated by the deposition of glacial till that is overlain by lacustrine or glacio-lacustrine sediments. First luminescence ages indicate a depositional age between 250 and 340 ka for sequence B. The drill core was transported from the drill site to the Institute of Geological Sciences, University of Bern, where it was analyzed and sampled. The first step in the analysis was scanning the whole core contained in the liners on a Multi Sensor Core Logger (MSCL; Geotek Ltd.) which provided measurements of the core (γ-)density, p-wave velocity and magnetic susceptibility. The liners were then opened under light sensitive conditions, the cores split in half to allow their macroscopic description, and one half was sealed from light and other alterating influences. After the description, the core was documented with a digital line scanner on the MSCL. After the documentation, a vane meter was used to determine the shear strength of the material and samples for pollen analysis, analysis of the carbon content, provenance analysis, and the measurement of cosmogenic nuclides 10Be and 26Al were extracted. This report provides limited information about the drilling operation, describes the available datasets form scanning and sample analysis, and the results of the first data processing as well as the tools used in the data analysis.

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