This study analysed marine sediment samples from areas with and without minimal hydrocarbon seepage from reservoirs underneath. Depth profiles of dissolved chemical components in the pore water and molecular biological data revealed differences in microbial community composition and activity. These results indicate that even minor hydrocarbon seepage affects sedimentary biogeochemical cycling in marine sediments, potentially providing a new tool for the detection of hydrocarbon reservoirs.

The lake drilling project at Lake Hallstatt (Austria) successfully cored 51 m of lake sediments. This was achieved through the novel drilling platform Hipercorig. A core-log seismic correlation was created for the first time of an inner Alpine lake of the Eastern Alps. The sediments cover over 12 000 years before present with 10 (up to 5.1 m thick) instantaneous deposits. Lake Hallstatt is located within an UNESCO World Heritage area which has a rich history of human salt mining.

Rock cores down to 2250 m depth, groundwater-bearing fractures, and drilling fluid were sampled for DNA to characterize the subsurface microbial community. In general, microbial biomass was extremely low despite the employment of detection methods widespread in low-biomass environments. The described contamination control measures could support future sampling efforts, and our findings emphasize the use of sequencing extraction controls.

The NICA-BRIDGE workshop proposes a milestone-driven three-phase project to ICDP and later ICDP/IODP involving short- and long-core drilling in the Nicaraguan lakes and in the Pacific Sandino Basin to (1) reconstruct tropical climate and environmental changes and their external controlling mechanisms over several million years, (2) assess magnitudes and recurrence times of multiple natural hazards, and (3) provide baseline environmental data for monitoring lake conditions.

Geologists can decipher the past climates and thus better understand how future climate change may affect the Earth's complex systems. In this paper, we report on a workshop held in Longyearbyen, Svalbard, to better understand how rocks in Svalbard (an Arctic archipelago) can be used to quantify major climatic shifts recorded in the past.

A magnetic fabric analysis provides information about the reorientation of magnetic grains and is applied to three sandbox models that simulate different stages of basin inversion. The analysed magnetic fabrics reflect the different developed structures and provide insights into the different deformed stages of basin inversion. It is a first attempt of applying magnetic fabric analyses to basin inversion sandbox models but shows the possibility of applying it to such models.

The newly established geodynamic laboratory aims to develop modern, comprehensive, multiparameter observations at depth for studying earthquake swarms, crustal fluid flow, mantle-derived fluid degassing and processes of the deep biosphere. It is located in the West Bohemia–Vogtland (western Eger Rift) geodynamic region and comprises a set of five shallow boreholes with high-frequency 3-D seismic arrays as well as continuous real-time fluid monitoring at depth and the study of the deep biosphere.

Seismic imaging while drilling (SWD) technology offers possibilities of imaging ahead of the drill-bit, which is valuable information for optimizing drilling efficiency. An SWD field test was carried out in August 2020 at an exploration drilling test site in Örebro, Sweden, with the aim to determine if the signals from hammer drilling can be used for seismic imaging around the drill-bit. A comparison with the seismic data generated with a conventional seismic source shows reasonable agreement.

Vertical incidence seismic profiling on the Iberian Massif images a mid-crustal-scale discontinuity at the top of the reflective lower crust. This feature shows that upper- and lower-crustal reflections merge into it, suggesting that it has often behaved as a detachment. The orogen-scale extension of this discontinuity, present in Gondwanan and Avalonian affinity terranes into the Iberian Massif, demonstrates its relevance, leading us to interpret it as the Conrad discontinuity.

New cable-free borehole memory sondes allow measurements in boreholes with very unstable walls, which is common, e.g., in soft sediments below lakes. The drill-pipe-mounted memory sondes can pass through narrowed zones. While being pulled up by the drill pipes, they measure natural radioactivity, velocity of sound, electrical conductivity, magnetizability, and the temperature of the borehole rocks. We describe the memory sondes and appendant depth devices, both tested in thorough field tests.

This contribution presents a new reference material, ASH-15 flowstone with an age of 2.965 ± 0.011 Ma (95 % CI), to be used for in situ U–Pb dating of carbonate material. The new age analyses include the use of the EARTHTIME isotopic tracers and a large number of sub-samples (n = 37) with small aliquots (1–7 mg) each that are more representative of laser-ablation spot analysis. The new results could improve the propagated uncertainties on the final age with a minimal value of 0.4 %.

We characterise a well-known fractured and faulted exposure of Cretaceous chalk in NE England, combining field observations with novel U–Pb calcite dating. We show that the faulting and associated fluid flow occurred during the interval of ca. 64–56 Ma, predating earlier estimates of Alpine-related tectonic inversion. We demonstrate that the main extensional fault zone acted as a conduit linking voluminous fluid flow and linking deeper sedimentary layers with the shallow subsurface.