Geological Institute

The behaviour of slowly moving rock slope instabilities in alpine regions is governed by the interaction between inherited structural discontinuities and externally imposed environmental forcing, yet the mechanisms linking these controls across scales remain poorly constrained due to the lack of continuous subsurface observations. Rock slope toppling represents a typical form of such structure-controlled deformation. Here, we present a comprehensive investigation of a structurally complex toppling rock slope in pre-Variscan metamorphic units in the Bedretto Valley (Swiss Alps). This landslide is intersected by the unlined Bedretto Tunnel over a length of approximately 450 m. The presence of the tunnel and the associated facilities of the Bedretto Underground Laboratory provides a unique opportunity to resolve spatially variable deformation.To understand the controls on the motion of this landslide, we installed a multi-parameter monitoring network, which integrates surface and subsurface measurements. It combines meteorological stations covering the toppling crown and toe, sectional groundwater pressure monitoring, and a 2-km-long distributed fiber optic sensing (DFOS) cable anchored along the Bedretto Tunnel. This configuration provides a unique internal view of deformation within the rockmass, enabling continuous, decimeter-scale observations of microstrain and temperature beneath up to 1500 m of overburden.The measurements reveal two distinct deformation responses of the landslide. First, reversible, centimeter-scale strain oscillations correlate with surface temperature fluctuations but exhibit anomalously high amplitudes and penetration depths, which cannot be explained solely by conductive heat transfer. This points to a non-local thermoelastic response, whereby far-field thermal stresses are generated and anisotropically transmitted through the fracture network within the rockmass. Superimposed on this cyclic thermoelastic background, the data reveal discrete, irreversible strain steps near critical fracture zones. These steps temporally coincide with major seasonal hydrologic events including sustained snowmelt and intense rainfall when a two-layer bucket model predicts corresponding peaks in groundwater storage and pressure transients. This correlation provides direct evidence for hydro-mechanically driven, progressive damage within the fracture network of the slope.Multivariate decomposition of the deformation time series isolates not only the dominant thermo-hydraulically driven cyclic signal, but also residual components characterized by spatially variable, and locally opposing, monotonic strain trends. These opposing trends are partially explained by the mechanical and geometrical heterogeneity of the fracture network and reveal the accumulation of progressive inelastic deformation. Beyond direct thermal or hydraulic forcing, such components suggest a creep-like weakening mechanism of the rockmass under quasi-static gravitational stress.These findings reveal the dynamics of a coupled thermo-hydro-mechanical system, in which seasonal forcing drives both reversible deformation and irreversible damage. The study thus highlights the critical role of discontinuities in controlling slope behavior, showing how transient hydrology and thermal cycling progressively degrade rockmass strength along pre-existing fractures and joints, ultimately weakening large rock slope failures.

The late Miocene cooling (LMC; ~7–5.4 Ma) represents a major global climate transition associated with declining atmospheric CO₂, large-scale aridification, and reorganization of terrestrial ecosystems. While cooling at high and mid latitudes during this interval is well documented, temperature changes in the tropical oceans appear muted. Existing tropical sea-surface temperature (SST) reconstructions based on alkenone unsaturation (UK’37​) are limited by proxy saturation at ~29 °C, potentially leading to an underestimation of tropical warmth. Here, we investigate tropical upper-ocean temperature evolution during the late Miocene using coccolith clumped isotope (∆47) thermometry, which reflects habitat-depth temperatures rather than regressed SSTs.We present new coccolith ∆47 temperature records from ODP Site 926 (Ceara Rise) spanning the late Miocene and compare them to late Pleistocene glacial and interglacial intervals from nearby ODP Site 925. Coccolith-enriched sediment fractions were carefully isolated and screened prior to ∆47 analysis. Results indicate muted tropical cooling of ~3 °C during the LMC, consistent with global temperature compilations. Notably, reconstructed late Miocene upper-ocean temperatures (~20–25 °C) are similar to those observed during Pleistocene interglacials, despite fundamentally different climate states characterized by Antarctic-only glaciation in the late Miocene and bihemispheric glaciation in the Pleistocene.These findings suggest that muted tropical cooling during the late Miocene is not solely an artefact of alkenone saturation.This study underlines the potential of coccolith clumped isotopes to provide constraints on upper-ocean temperatures, avoiding uncertainties associated with regressing proxy signals to SST. However, changes in coccolithophore depth habitat and water-column stratification remain key uncertainties. Ongoing paired coccolith–foraminifera ∆47 and foraminifera δ¹⁸O analyses will improve interpretations of tropical ocean temperatures and vertical gradients across contrasting climate states.

First-time petrological and mineral-chemical studies of L6 chondrites from Bursa (Turkey) were done, and the conditions of shock metamorphism were justified. A new age of the zircon-reidite was determined at 4.2 Ga (U-Pb (TIMS)).Gray gneisses, TTG, enderbate rocks, and amphibolites from Murmansk and Central Kola megablocks of the N-W part of the Fennoscandian Shield were dated using SHRIMP and U-Pb (TIMS) on zircon, with ages ranging 3.7-3.2 Ga.Protoliths of country rocks, based on Sm-Nd data, reflect TDM values 3.0 to 3.5 Ga, with ɛNd values ranging from +2 to -3.Concentrations of PGE and Ir anomalies were studied for the basement rocks of the continental crust using ICP-MS, reflecting an extraterrestrial (impact) contribution during the early formation stages of the two megablocks of the N-W part of the Fennoscandian Shield.Additionally, the basement rocks show high concentrations of ore metals (ICP-MS data) such as Fe, Pt, Pd, Ni and other elements unusual for Earth rocks (Koeberl et.al, 2024; Treatise on Geochemistry, 2003; Van Kranendonk et.al, 2019). This research was carried out in accordance with the research topics outlined in Scientific Research Contracts FMEZ-2024-0004. Many thanks to A.N. Larionov for the U-Pb (SHRIMP) analysis. Devoted to memory of the outstanding geochemistry Derald Wasserbourg from USA for artificial spike 205 Pb for U-Pb (TIMS) measurements single grains baddeleyite and zircon.

The early Eocene long-term warming was punctuated by relatively short (50 to 200 kyr) and abrupt warming events, which are used as analogues to understand current anthropogenic global warming. Among these hyperthermal events, the Eocene Thermal Maximum 2 (ETM2) corresponds to an orbitally paced release of 2,600 to 3,800 Gt of carbon at 54.1 Ma. It has primarily been identified in deep oceanic settings, while terrestrial and coastal records of this event remain scarce. Indeed, the ETM2 has only been identified in shallow marine settings in a few locations (Arctic, USA Atlantic coast, Egypt, India, and New Zealand), hindering a full understanding of its environmental impact.Here, we present a high-resolution multi-proxy record from a newly drilled 25-m-long core in southwest Belgium (Mons Basin), at a paleolatitude of ~40°N, combining Gamma-ray spectrometry, mineralogy (XRD bulk-rock and clays, TEM, grain-size) and organic geochemistry (δ13Corg, Rock-Eval®, and palynofacies). Sedimentological interpretation indicates a siliciclastic tidal shallow marine environment (a few tens of meters water depth). Using an age model based on nannofossils, dinocysts and cyclostratigraphy, the ETM2 is recorded over approximately 2.5 m by a ~1‰ negative carbon isotope excursion (CIE) located within the NP11 nannofossil biozone. The peak of this CIE corresponds, with a slight delay, to an increase in carbonate content and nannofossil abundance, suggesting enhanced primary productivity related to an intensified hydrological cycle and higher nutrient inputs during the ETM2. An increase in detrital input is also suggested by the transition to coarser grain size. After a progressive decline in kaolinite, illite, and chlorite contents in the clay fraction, smectite becomes the dominant clay mineral during the CIE, possibly pointing to a transgressive event in relation with the ETM2, as also suggested by palynofacies and dinocyst assemblages.This study presents the first high-resolution record of the ETM2 in the coastal environments of the southern North Sea Basin, preserved in the Mons Basin. In these settings, the ETM2 is associated with a deepening trend, possibly related to sea-level rise, as well as with increased primary productivity and detrital inputs, which point to an enhanced hydrological cycle.

New macroscopic fossils have been discovered in the Dzhezhim Formation of the Upper Precambrian Chetlas Group of the South Timan, exposed in the Yugydiag Quarry: three-dimensional casts and molds of discoidal colonial Ediacara-type soft-bodied organisms; and Miaohe-type carbonaceous compressions of algal organisms. Finding of a various macroscopic fossil in the Dzhezhim Formation clarifies the age limits of its deposition, whose stratigraphic position in the Upper Precambrian section was controversial.

Geophysical investigations were conducted utilizing Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) to assess a Non-Aqueous Phase Liquid (NAPL) contaminated site in the southeast of China. Traditional drilling and sampling methods combined with geochemical analysis are limited in deriving reliable spatial interpolations due to low sampling density and high heterogeneity of shallow groundwater. Variations in soil physical properties, such as conductivity and dielectric properties, resulting from NAPL infiltration, provide the physical basis for geophysical detection. While the combined use of ERT and GPR is established in geophysics, its effective application to NAPL sites remains challenging due to complex site conditions and ambiguous signatures. Our ERT results reveal high resistivity anomalies potentially indicative of NAPL contamination, and overlaying GPR attribute analysis (including amplitude, phase, coherence, and texture) onto these results enhances subsurface characterization and anomaly discrimination. The integrated approach demonstrates its capability to clarify subsurface contamination patterns under heterogeneous conditions, providing a spatially continuous interpretation framework that complements sparse direct sampling.

We report results on the age estimates of the Paleogene diatom datums derived from the magnetostratigraphy at the marine Cenozoic stratigraphic section of the Kvachina Bay, West Kamchatka. Based on a direct correlation with the Geomagnetic Polarity Time Scale, it was possible to determine the age of such levels in the interval between Subchron C13r (35.10–33.73 Ma) and Subchron C9r (27.86–27.44 Ma). Of greatest interest are the dates of the first and last occurrences of Lisitzinia ornata (27.71 Ma and 27.54 Ma respectively), and the first occurrence of Rocella gelida (27.49 Ma). This is the first experience of absolute age estimates of Oligocene diatom biohorizons based on magnetostratigraphy not only in Kamchatka sections, but in the North Pacific region in general. A comparison was made between the obtained age estimates and those published in the literature based on the study of deep-sea cores in various regions of the World Ocean.

Introduction Coastal zones in bay cities are characterized by high population density, concentrated economic activities, and integrated socio-ecological systems. The dynamic interaction between industrial structural evolution and coastal development in such areas exerts profound impacts on both regional economic growth and ecological sustainability, making it critical to clarify their correlation. Methods By integrating historical marine maps (1958–2020) and remote sensing images (1986–2020) of Xiamen Bay, we extracted the coastline length and utilization data of Xiamen (a typical bay city). Artificial coastlines were categorized into four types based on their functional attributes. The Spearman rank correlation coefficient was then applied to analyze the relationships between coastline length, utilization type, and urbanization indicators, linking these variables to the structure of the primary, secondary, and tertiary industries. Results and Discussion The results indicate that: 1) From 1958 to 2020, the natural coastline length of Xiamen Bay decreased by 283.57 km, accompanied by continuous expansion of artificial coastlines. Specifically, First-type artificial coastline increased by 152.73 km (1958–2002) but decreased by 134.48 km (2002–2020); Second and third type coastlines expanded by 117.07 km and 154.61 km respectively; Fourth-type coastline emerged after 2002 and reached 23.23 km in 2020. 2) At the regional scale, First-type coastline expansion showed a phased positive correlation with the primary industry; Second and third type coastline development was positively correlated with the secondary and tertiary industries (but negatively correlated with the primary industry). 3) The evolution of Xiamen’s coastal zone has shifted from a single economic benefit orientation to a synergistic “economic–ecological–social” model, corresponding to four stages: agricultural reclamation-dominated, initial export-oriented economy, bay-type city construction, and high-quality development transition. Notably, this shift is closely tied to industrial structure adjustments, providing a reference for bay cities to balance economic growth and coastal ecological protection.