The Eifel region in Germany hosts hundreds of distributed volcanoes of Quaternary age, including the Laacher See volcano that produced an eruption of VEI (volcanic explosivity index) 6 13 kyr ago, and is underlain by one of the youngest silicate–carbonatite intrusive complexes worldwide. Recently, three workshops were held to sharpen scientific questions of global scope and relevance to study this type of volcanism by drilling. This report summarised the workshop outcome with a clear science plan for the drilling project.

Choosing samples from large sections of hard-rock cores often relies on preliminary chemical analyses, which can be limited and therefore misrepresentative of full chemical variability. This study adapts X-ray fluorescence core-scanning techniques for use on hard-rock basalt cores to outline a method that provides accurate chemical information in greater detail relative to traditional analytical methods. The presented workflow suggests significant contributions to new and legacy core research.

This study investigated previously underexplored deep-water movement in the Bushveld Complex. Analysis of water and rock data from a deep exploration well revealed distinct changes in water chemistry at 450 m below ground level, associated with a severely fractured rock layer and a deep rock conduit. These features indicate potential deep, saline, gas-rich water pathways containing high dissolved salts and specific metals, providing insight into deep fluid migration in fractured hard rocks.

State-of-the-art scientific drilling frequently involves X-ray scanning to get an initial overview of the recovered cores. The X-ray scanner generates a huge 3D image, usually explored with a specialized computer located several meters away from the cores. We suggest using paper summaries of the X-ray images for a more focused description without digital distractions. In particular, we propose creating a virtual image that wraps around the core, similar to how the Shroud of Turin shows a body.

To explore links between human evolution and environmental change, the Chew Bahir basin in southern Ethiopia, a sedimentary climate archive, was investigated through a series of scientific drilling expeditions. We share key lessons from planning, site selection, drilling strategy and core processing, with a focus on the awards and challenges in collecting and merging twin sediment cores into a near-continuous record to provide practical lessons for future projects.

A workshop on the the scientific value and use of a 4500 m deep borehole on the campus of TU Delft in the Netherlands was held in June 2024. The borehole will serve as an observation infrastructure for processes in the underground related to human activities, such as exploitation of energy resources like geothermal energy or storage of heat or gas. The location is of great interest for this purpose as there are already two deep geothermal wells and shallow wells for heat storage.