Conference Agenda

Scientific drilling is a well-established tool in Earth sciences and related disciplines. For drilling on land, the International Continental Scientific Drilling Program, ICDP is the major player providing implemental funding and technical support. The largest number of ICDP projects aim at drivers of Paleoenvironmental and Paleoclimate evolution with a focus on dramatical and rapid changes. While Quaternary archives such as lacustrine sediments still predominate, more and more Mesozoic to Paleozoic time slices of dramatic System Earth transformations come into the play. Even Precambrian times are on the agenda such as Neoproterozoic Snowball Earth, Early Precambrian oxygenation of the atmosphere, or Early Earth origin and evolution of life.

Another key topic in the ICDP are Geohazards including mainly seismic and volcanic risk and research on landslides or a combination of cascading disastrous events. First approaches in this field of science were often related to the feasibility of drilling in fault zones or active volcanic regions while current ideas focus on monitoring and testing.

Energy-related scientific drilling projects on e.g., geothermal challenges and other critical resources often acquire funding from national governmental resources. In contrast, fundamental basic research questions are usually developed as bottom-up international academic initiatives. In order to bridge the gap between these two advance lines in geothermal research, ICDP has now established new funding priorities including not only ‘World-Class Science’ and ‘World-Class Sites` but also ‘World-Class Opportunities’.

This contribution will summarize current trends and initiatives in terms scientific objectives and will elucidate funding challenges as well as chances.

To define parameters for future climate change scenarios (IPCC) and their consequences for ecosystems, it is of paramount importance to improve our knowledge of timing, duration, and intensity of past climatic variability and subsequent environmental impact, especially on long geologic time scales and in key regions such as the Tibetan Plateau. Considering that the Tibetan Plateau serves as the source of several major rivers the future hydrological development will clearly have a significant societal impact. Nam Co is one of the largest and deepest lakes on the Tibetan Plateau. Due to this location at the intersection of Monsoon (increased precipitation) and Westerlies (increased evaporation) paleoclimate proxies derived from sediments of Nam Co clearly reflect the spatial and temporal interplay and thus the dominance of one of the two circulation systems.

Seismic data show that the Nam Co basin contains >800 m of well layered undisturbed sediments. Sediment accumulation rates measured on a 10.4 m reference core, seismostratigraphic investigations, and molecular clock analyses suggest an age of the seismically imaged sequence of >1 Mio years. Instead of drilling the entire >800 m sediment sequence in the center of the lake we will use the fact that layers are dipping towards the center of Nam Co producing a higher accumulation rate there. By splicing together multiple cores from three different sites it will be possible to cover the same depositional history found at >800 m in the center, i.e., 1 Ma.

Fossil deep-sea macrobenthos is scarce due to the rarity of onshore deep-sea sediments. Therefore, hypothesized migrations of shallow shelf taxa into the deep-sea after phases of mass extinction or oceanic anoxic events (onshore-offshore pattern) is not constrained by the fossil record. To resolve this conundrum, we investigated 1,475 deep-sea sediment samples (Atlantic, Pacific, Southern oceans; 200 - 4,700 m paleo-water depth). Ca. 41,500 spine fragments from Holasteroida and Spatangoida (Atelostomata) document a continuous occurrence of the groups since 104 Ma (late early Cretaceous). Literature records suggest even an older age (115 Ma). A gradual increase of spine tip morphotypes occurs since the Albian. An abrupt reduction in spine size and morphological inventory following the Cretaceous-Paleogene (K-Pg) Boundary Event is expression of a “Lilliput Effect”, related to nourishment depletion in the deep-sea. The post-event recovery lasted at least 5 Ma. Post-K-Pg Boundary Event assemblages seem to evolve progressively without any morphological breaks towards modern deep-sea assemblages. This observation is interpreted to result from in-situ evolution in the deep-sea and not from onshore-offshore migrations. The calculation of the “atelostomate spine accumulation rate” (ASAR) reveals low pre-Campanian values, possibly related to high remineralization rates of organic matter in the water column in the course of the mid-Cretaceous Thermal Maximum and its aftermath. A Maastrichtian cooling pulse marks the irreversible onset of fluctuating but generally higher atelostomate biomass that persists in the Cenozoic.

Between 5.97-5.33 Ma, kilometre-thick evaporites were deposited in the Mediterranean Basin during the Messinian Salinity Crisis (MSC) under strongly negative hydrological budget. In the light of the IMMAGE initiative to drill the Mediterranean-Atlantic gateway, we present here the reconstructed continental mean annual temperatures (MAT) using branched glycerol dialkyl glycerol tetraether (brGDGT) biomarkers for the MSC Stage 3 (5.55-5.33 Ma) and compare them with continental temperature values obtained from Δ₄₇ clumped isotope geochemistry of paleosol carbonate nodules from few Mediterranean locations. The biomarkers were extracted from outcrops onshore and offshore sites around the Mediterranean Basin. Calculated MATs for the 5.55 to 5.33 Ma interval show values around 16 to 19 ºC for the Malaga, Sicily and Cyprus outcrops. The MAT values for DSDP Leg 13 holes 124, 134 and Leg 42A holes 374 and 376 are lower, around 13 to 16 ºC. Comparing the brGDGT-MAT values with Δ₄₇-MAT values from carbonate nodules, shows high congruence between both approaches. For the northern Mediterranean Δ₄₇-MAT is 24.6 ± 1.6 °C and brGDGT-MAT is 19 ± 4.8 ºC. For Cyprus Δ₄₇-MAT is 20.3 ± 1.7 °C and brGDGT-MAT is 18 ºC ± 4.8 ºC. Given the very different nature of the used paleoproxies, the similarity of the obtained MAT values provides a strong indication of (cross)validity in sampled sections. Additionally, the measured δ¹⁸O for the carbonate nodules used for the Δ₄₇-MAT show high δ¹⁸O of the soil water (~ -5 ±0.7‰) indicating highly evaporative conditions for the two onland Northern Apennines and Cyprus locations.

Shallow weathering patterns and linked hydrostratigraphy in topographic recharge areas are rarely explored even for used groundwater flow systems, as (scientific core) drilling was usually carried out in downstream zones of productive resources. In the Hainich Critical Zone Exploratory (NW Thuringia, Germany), we constructed a well network encompassing the recharge area (hilltop, midslope) in discharge direction (footslope) for long-term monitoring of the links between surface and subsurface biogeosphere (Küsel et al., 2016). In total, ~730 m of rock cores from the limestone-mudstone alternations of the Upper Muschelkalk, including drillings in the thick hillslope aeration zone, were used for the exploration of hydrogeological functions, flow paths and endolithic habitats (Kohlhepp et al. 2017). Based on the core and monitoring data, an advanced conceptual model on multidirectional flow patterns and subsurface ecosystem compartmentalization was developed (Lehmann and Totsche, 2020). Novel and surprising findings revealed unseen patterns in the Upper Muschelkalk flow system: confined weathering phenomena in fissures and pores indicate localized, oxic conditions in sections that were previously encountered elsewhere as anoxic and unweathered. This indicates a higher complexity of flow and transport pathways (e.g., oxygen supply) than commonly expected, despite simple layer-cake geometry of the bedrocks. Besides relief position, it points to a strong influence of fractures on flow in the aeration zone.

References: Kohlhepp et al. (2017): https://doi.org/10.5194/hess-21-6091-2017; Küsel et al. (2016): https://doi.org/10.3389/feart.2016.00032; Lehmann and Totsche (2020): https://doi.org/10.1016/j.jhydrol.2019.124291