Geological Survey of Austria

We present results from the NBP03-01A-20PCA sedimentary record which was recovered from the outer continental margin of the central Ross Embayment. Sediments comprise mud, with sub-angular to sub-rounded fine to coarse sand, common pebbles and rare cobbles. A paleomagnetic age model indicates the succession has a basal age of c. 1.1 Ma with magnetic reversals at 4.21 m, 5.74 m, and 5.85 m depth correlated with C1n-C1r.1r-C1r.1n-C1r.2r geomagnetic reversals.Magnetic mineral concentration and micro IBRD data were considered a proxy for the proximity of the Ross Ice Shelf grounding zone and calving line to the core site. High magnetic mineral concentration and high terrigenous content correspond to sediments deposited beneath a floating ice shelf or from icebergs calved from that source. Time series analysis of these data indicate the advance and retreat of the Ross Ice Shelf—and by extension the West Antarctic Ice Sheet— were primarily paced by 41,000-year-long obliquity cycles until at least 400,000 years ago.Insolation was predicted to control Antarctic ice volume; however, the frequency of glacial cycles inferred from global benthic foraminiferal oxygen isotopic and ice core records were originally interpreted to indicate that Antarctic ice volume variations were paced by 100,000-year-long (eccentricity) cycles from about 800,000 years ago. This interpretation was never confirmed from sedimentological reconstructions of ice margin advance and retreat cycles around Antarctica.On seasonal timescales, ablation at the base of the western sector of the Ross Ice Shelf is controlled by the inflow of Ross Sea surface waters warmed by the summer sun. On orbital timescales, season length is suggested to control Antarctic temperature, with long summers and short winters leading to gradual warming and vice versa. We suggest that ablation, driven by circulation of warm summer surface waters under the ice shelf, is the mechanism by which long-term insolation control of sea surface temperatures produced the orbitally paced cycles observed here.Our study reconciles the historical mismatch between high latitude insolation variations and glacial cycles inferred from distal records. We suggest that high-latitude insolation controlled Southern Ocean heat uptake and continued to be the main pacemaker of Antarctic glaciations well into the late Pleistocene. More sedimentary records from Antarctica and the Southern Ocean are required to reconstruct the true glacial history and whether different sectors of the margin are sensitive to different forcings.Ohneiser, C., Hulbe, C.L., Beltran, C. et al. West Antarctic ice volume variability paced by obliquity until 400,000 years ago. Nat. Geosci. 16, 44–49 (2023). https://doi.org/10.1038/s41561-022-01088-w

Abstract The Bockflies Formation represents parts of the Ottnangian Stage of the Lower Miocene in the Central Vienna Basin and is characterized by the type section from the Matzen 269 well. However, a detailed sedimentological characterisation of the type section has not been published. Previous studies on the Bockflies Formation predominantly focused on fossil assemblages, which indicated a lagoonal depositional environment with riverine input. This study intends to complement previous paleontological studies with a detailed sedimentological analysis, involving lithological, petrographical, ichnological, and macrofossil content descriptions of the cored sections from the Matzen 269 well. The sedimentological data was thereafter used to establish lithofacies and determine depositional environments represented by the cores. This suggests that the Bockflies Formation in the study area largely represents a coastal lagoon depositional setting, with identified depositional environments include lagoon, washover fan, channel fills (inlet) and shoreface. The lagoon facies is the most dominant and relevant sealing facies in the Bockflies Formation and could span tens of kilometres at its widest point and most likely formed due to coastal sea flooding. However, a connection was maintained between the lagoon and the sea, representing an inundation model, with modern analogues found in the Venice Lagoon in Mediterranean Sea and the Curonian Lagoon in the Baltic Sea. The selected core sections were also evaluated for their sealing potential as the formation is a regional caprock for the underlying fractured carbonate reservoirs. The sealing potential of a caprock system depends primarily on its geometry, storage capacity, and structural integrity. To evaluate the sealing potential, lagoon facies were further subjected to XRD, QEMSCAN, MICP and coreDNA analyses. Based on these, the lagoon facies would most likely act as an intraformational seal, given the presence of other non-sealing facies. Rock strength data obtained through scratch testing indicate a subtle variation in strength within the lagoon facies, attributed to clay content. Moreover, the compositional make-up of the lagoon facies is akin to ‘sealing shales’ reported elsewhere. Additionally, XRD analysis revealed that illite is the dominant clay mineral across the lagoon facies, which is a non-reactive clay mineral.

The Ennedi Plateau in Chad in north-central Africa exposes an outstanding example of a palaeo-ice stream glacial landsystem of late Palaeozoic age, with an assemblage of geomorphological structures of comparable preservation quality to those found in Quaternary deglaciated landscapes. Satellite images and various methods to combine acquired satellite data (e.g. band-ratio technique) have been used to interpret proglacial, ice-marginal and subglacial structures. The main goal of the study is to produce a detailed and more in-depth analysis of newly found structures that enhance our understanding of ice sheet behaviour in the Ennedi Plateau during the LPIA.We report the first known evidence of soft-sediment striated surfaces from outcrop, testifying to the existence of a soft-deformable bed. This deformable bed interpretation can probably be upscaled to explain the extensive swarms of mega-scale glacial lineations mapped previously across the plateau. Furthermore, we identify the first known fully preserved grounding zone wedge (GZW), replete with three-dimensional geometry, in the rock record. This unique structure exhibits a well pronounced slope and a convex topography. Its presence allows the position of the former coastline to be reconstructed as it is assumed that ice streams terminated into a former ocean basin. Building on the studies by Le Heron (2018) and Kettler et al. (this issue), our analyses permit unprecedented insights into the behaviour of a significant, mid-latitude, marine-terminating ice sheet during the LPIA.

Alpine regions are important as “water towers” in regional water supply of clean groundwaters due to their increased precipitation rates and their unspoiled environment. However, they are often characterised by complex geology structures, covered by down-sliding glacio-fluvial sediments. Groundwater recharge conditions and mean transit times (MTTs) are fundamental components of mountain watershed hydrological systems. Here, we used measurements of stable water isotopes of precipitation, pore water, surface and groundwater. In addition, measurements of environmental age tracers (222Rn, CFCs, 3H, 3He, 4He and 14C) were performed to investigate groundwater MTTs from springs in glacio-limnic sediments (<20 m) and deeper wells (>20 m) located along a mountainous hillslope (1,400-800 m) within the Subersach watershed near Sibratsgfäll, Bregenzer Wald, Austria. The near surface spring waters contain 3H and CFCs in excess. The deeper artesian well samples contain 3H and CFCs, in addition to elevated terrigenic 4He and low 14C values, suggesting a mixture of waters characterised by residence times that are modern (<70 years) and pre-modern (>70 years). We show that binary-mixing MTT models with distinct young and old fractions are needed to explain the full suite of environmental tracers, further supporting the importance of groundwater mixing processes.The vertical unsaturated infiltration in silt/sand dominated glacio-lacustrine sediments were estimated by seasonal variation of 2H/18O-isotopes in pore-water to be 1-4 m/year approximately. Precipitation in the Flysch dominated area at higher altitudes is transported partly as mountain bloc recharge and ascends into the glacial sediments, indicated by temperatures 2-3° C higher than the mean surface temperature. The MTTs of the shallow groundwater (<20 m) estimated by a combination of isotopes 2H/18O, 3H/3He, 13C/14C and tracer gases (CFC, SF6) indicate ages between some months and 4 years. Radon measurements identify springs supplied by very young drainage or surface waters. Deeper (>20 m) artesian wells in the western part are dominated by MTT older than 70 years.The research project “Understanding of Extreme Climatological Impacts from Hydrogeological 4D Modelling” (EXTRIG) was funded by the Austrian Academy of Sciences.

The use of geothermal energy from tunnels offers an environmentally friendly option for heating and cooling of buildings in the vicinity of the tunnel structure. In the research project “Thermocluster”, the geothermal potential of the Brenner Base Tunnel (BBT) was analysed and the utilization of the low-temperature heat to the city of Innsbruck was evaluated. A possible optimization on the geothermal performance was explored by separating colder sectional discharges from the total tunnel water drainage system. Further, the use of decentralized and centralized heat pumps, as well as heat distribution with different district heating networks (local low temperature heating and cooling networks, low-temperature network, classic district heating network), was investigated using process simulation. The results indicate that an optimization of the temperature of a subset of the total tunnel water discharge is possible. Furthermore, it could be shown that wide fluctuations in the efficiency of the heat pump can be expected. In addition, a rough cost estimation regarding the installation and distribution costs of the tunnel heat with different heat network variants is provided. This shows that the variant using decentralized heat pumps in the buildings and distribution via an anergy network is the most favourable in terms of installation.

The Agenda 2030 of the United Nations stipulates an ambitious set of 17 Sustainable Development Goals (SDGs). They were globally agreed upon and demand coherent, context-specific implementation at the national level. To address the complexity of challenges therein, the Agenda is designed to be integrated, indivisible, and universal. The numerous multifaceted interactions in-between the SDGs and with corresponding measures pose a complex challenge for decision-makers implementing them worldwide that requires support for a comprehensive discourse in the science-society-policy arena. Research on the interactions between the SDGs has been flourishing and can help to understand where policy options might be most successfully located. A catalytic effect on several other goals is, e.g., often attributed to SDG 6 on water and sanitation. However, beyond the where to locate policy options, it is similarly important to understand how potential policy options would affect the SDGs and their targets. We developed eleven options and 85 measures as context-specific pathways to advance the SDG 6 Targets in Austria. As a country in the Global North and with a generally far-established water and sanitation infrastructure and management, this responds to the Agenda's demand for universal applicability and can serve as an example to illustrate potential challenges beyond basic infrastructure provision and management. The proposed options cover resources-oriented sanitation, blue-green-brown infrastructure, efficient use and integrated management of water resources, maintenance and restoration of ecological functions of inland waters, reduction of diffuse discharge of nutrients and problematic substances as well as trace substances, water, sanitation and hygiene in public spaces, groundwater protection, development cooperation as well as co-design and co-creation. Their effects on the SDG 6 Targets are evaluated using a 7-point-scale. The evaluation method is simple and practicable, and fosters discourse on the entire water cycle amongst the expert group applying the method. The evaluated effects on the targets are found to be unanimously positive or neutral, but trade-offs might arise when including other SDGs in the assessment, making an expansion of the evaluation necessary for coherent implementation. The results can be used as a baseline to support follow-up discussions with stakeholders and decision-makers.