This talk focuses on disentangling the signatures of the lithospheric scale processes such as slab break-off and/or tearing within the sedimentary basin architecture. Sedimentary basins are sensitive recorders of the interplay between dynamic processes controlling the deformation of the lithosphere, climate and sea-level variations. Variations in sedimentary succession, recorded as variable grading, thickening and/or depositional trends across the basin or series of basins, are often attributed to a wide range of lithospheric-scale processes. This cause-and-effect relationship is based on deductive reasoning and so far, a direct link and quantitative assessment of the effect of these processes on the basin(s) architecture are missing. The inversion of basin fill data to derive the dominant mechanism responsible for the observed basin architecture is complicated by incomplete preservation in the geological record or sparseness in data coverage. Furthermore, many processes may have operated coevally or at different spatiotemporal scales or at different amplitudes, making retrieving the information challenging. Therefore, to distinguish slab break-off and/or tearing-induced signals within sedimentary basins from other signals (e.g., climate, sea level variations) an interdisciplinary approach is needed. In this talk, field observations and results of 3D geodynamic and stratigraphic numerical models inspired by the Molasse Basin and Dinaridic Lake System are combined to understand the set of parameters leading to the preservation of these signals in sedimentary records.

We reassess the architecture and tectonic history of the Western Alps based on recent knowledge developed at rifted margins. First, we replace the main Alpine units of our study area into a synthetic rifted margin template based on diagnostic petrologic, stratigraphic, and structural criteria. We find that some units previously attributed to the internal part of the thick-crusted Briançonnais domain may rather derive from the thin-crusted Prepiemonte hyperextended domain. We assert that the Briançonnais and Prepiemonte domains were separated by a mega-fault scarp. Second, we revisit the Paleogeography of the Alpine Tethys, suggesting that the Briançonnais was a ribbon of little thinned continental crust between two overstepping en-échelon rift basins, namely the Valais domain to the northwest and the Piemonte domain to the southeast. We affirm that this uneven-margin architecture can explain most of the Western Alps’ complexity. In our kinematic model, convergence between Adria and Europe was mainly accommodated by strike-slip movements in the Western Alps until the late Eocene. Orogeny began with the reactivation of the mega-fault scarp between the Briançonnais and Prepiemonte domains, which we name Prepiemonte Basal Thrust. Once hard collision started, the main shortening stepped inboard into the Valais/Subbriançonnais domain along the Penninic Basal Thrust.

During Ediacaran to earliest Cambrian times, the Cadomian Orogen formed a system of magmatic arcs and marginal basins at the northern periphery of the Gondwana supercontinent. The orogenic belt was structured in the geotectonic style of the recent western Pacific. The Saxo-Thuringian Zone forms part of the northern Bohemian Massif and contains a number of good preserved fragments derived from the peri-Gondwanan Cadomian Orogen (e.g. the Schwarzburg Antiform, the Lausitz Block, the Eastern Sudetes). Here, we present a massive dataset of LA ICP-MS U-Pb ages and Hf-isotopes from detrital and magmatic zircon of sedimentary and igneous rocks from these areas. Sedimentary rocks are represented by arc-derived greywacke and mudstone turbidites in a back-arc and retro-arc setting. Further, glacio-marine diamictites and high-mature quartzites display passive margin deposits situated more proximate to the cratonic hinterland. U-Pb ages of detrital zircon form populations, which point to a West African hinterland during the time of deposition. The stratigraphic age of the basin fillings is bracketed between the maximum depositional age of the sedimentary rocks at c. 560 Ma and the age of intrusion of c. 539 Ma old granodiorite plutons, which intruded the isoclinal deformed greywacke-mudstone deposits of the marginal basins in the Cadomian orogenic system. The Cadomian crustal evolution is dominated by the recycling of continental crust from the West African hinterland as suggested by the dominance of zircons with negative εHf values. Juvenile arc magmas became contaminated by the recycling of Eburnian and Archaean crust during long Cadomian magmatic arc activity.

We present the first systematic U-Pb-Hf isotope data of detrital zircon grains from gneiss units of the southern Black Forest, preserving different stages of the pre-, syn- and post-Cadomian evolution. Protoliths of Murgtal metagreywackes were deposited during the Ediacarian at <550 Ma and sourced from the Avalonian-Cadomian Belt (550-700 Ma; ~70%) and Sahara Metacraton (760-1045 Ma, 1850-2250 Ma, 2720-3230 Ma; ~30%). In contrast, metasedimentary rocks of the Wiese-Wehra and Todtmoos gneiss units reveal late Devonian depositional ages at <370 Ma, but in different geotectonic settings. Wiese-Wehra metagreywackes provide evidence for the existence of pre-Cadomian oceanic crust formed at 610 Ma (εHf_t = +5 to +8), accreted to the Cadomian Belt at ca. 540 Ma, and successively reworked between 490 and 430 Ma (εHf_t = +1 to +6). Finally, these rocks became part of an early Variscan arc-back arc system with juvenile input at 370 Ma (εHf_t = 0 to +10). Todtmoos metaarkoses mainly reflect subduction-related magmatism at 490-420 Ma (~88%), and at 380 Ma (^~10%) in an evolved continental arc setting (εHf_t = -2 to -8). In combination, existing data from the Black Forest and other basement units throughout Europe provide evidence for the amalgamation of pre-Cadomian juvenile terranes along the northern margin of Gondwana until 540 Ma, followed by a complex rift history, accompanied by subduction between 500 and 400 Ma. They further point to the existence of an oceanic arc-back arc system, which has been located south of the Armorican terrane assemblage at 380-365 Ma.

We present new microstructural evidence and geochronological data from brittle structures sampled in an active quarry located in the Weschnitz Pluton in the southern Odenwald Crystalline Complex (OCC). Open joints and fractures are the primary pathway for fluids in crystalline rock and thus crucial in the utilization of crystalline formations for geothermal energy and long term nuclear storage.
The quarz-monzodioritic wall rock was emplaced around 344.4+-0.6 Ma ago into a considerably thickened crust in in about 18 km depth in a continental arc setting (Altenberger & Boesch, 1993; Altherr, 1999; Henes-Klaiber, 1992). Visean lamprophyre dikes bound to NNE-SSW striking normal faults relate to post-orogenic collapse and mark the onset of a multiphase history of extension and uplift, during which pre-existing variscan structures were repeatedly reactivated (von Seckendorff et al., 2004). While the variscan evolution is fairly well constrained (e.g. Todt et al., 1996; Krohe, 1996; Reischmann, 2001; Stein et al., 2022), brittle structures in the southern OCC have not yet been dated directly.
Most of the sampled joints measure between 2 and 10 mm and are sealed, one specimen has a thickness of 15 cm and is not sealed completely. In thin section, several types of joint mineralizations were identified, with syntaxial elongate blocky quartz with growth zoning and syntaxial blocky calcite with growth zoning being the most common types. Fractured calcite veins are often associated with hematite indicating later reactivation. U-Pb data obtained from LA-ICP-MS analyses on 15 samples splits into 2 age groups of around 300 Ma and 60-50 Ma.