Memristive Bauelemente für neuronale Schaltungen

The present post-doctoral thesis covers 14 original publications, which result from my work as research assistant between 2011 and 2015 at the Institute of electrical engineering at the technical faculty of the Christian-Albrecht university at Kiel. During this time my research work was strongly guided by the question how to understand memory and learning in brains and how we can build up non-biological systems, which function similar to those. In particular, I focused on the usage of new non-volatile memory technologies and electronic circuits for neuromorphic systems. Thus, the development of non-volatile devices and electronic circuits as well as biological models based on those devices is at the heart of this post-doctoral thesis

Three-dimensional (3-D) seismic imaging of conduits and radial faults associated with hydrothermal vent complexes (Vøring Basin, Offshore Norway)

Here, we document a suite of radial faults associated with hydrothermal vent complexes in the Vøring Basin, offshore Norway. These complexes have pyramid-shaped, cylindrical- and conical-shaped conduits, with a dome-, or eye-shaped morphology at their summit, intruding on Paleogene sedimentary rocks. Hydrothermal vents are intimate with the tips of magmatic sills that were emplaced at depths ranging between 1800 and 5800 ms Two Way Travel Time (TWTT). At shallower depths of 1800 to 3000 ms TWTT and intermediate depths of 3000 to 5000 ms TWWT, magmatic sills regularly intersect the lower parts of the vent conduits, which are characterized here as pipes. An important parameter that is used to characterize the morphology of a hydrothermal vent conduit is the width of the conduit, which is defined as the longest axis marking the extent of the vents' conduit within the surrounding host-rock strata. Our findings reveal that radial faults are commonly associated with the summits of hydrothermal vents, implying the existence of local stress fields around the vents, where the maximum compressive stress is radial and minimum stress is circumferential, which overrides the regional stress field and indicate variable stress regimes as opposed to tectonic faults. Importantly, circumferential stretching due to catastrophic plumbing of hydrothermal fluids, differential compaction and intensive fracturing enabled the polygonal faults to realign in a radial pattern resulting in the formation of radial faults at the vent summit. As a corollary of this work, we hypothesize that pyramid-shaped hydrothermal conduits are possibly markers of protracted sill emplacement in sedimentary basins

Giant paleo-seafloor craters and mass wasting associated with magma-induced uplift of the upper crust

Giant seafloor craters are known along many a continental margin with recurrent mass-wasting deposits. However, the impact of breakup-related magmatism on the evolution of such craters is barely understood. Using high-quality geophysical datasets, this work examines the genetic relationship among the location of magmatic sills, forced folds and the formation of giant paleo-seafloor craters underneath an ancient mass-transport complex in the Møre and Vøring basins, offshore Norway. The data reveal that forced folding of near-seafloor strata occurred because of the intrusion of several interconnected magmatic sills. Estimates of 1-dimensional uplift based on well data show that uplift occurred due to the intrusion of magma in Upper Cretaceous to Lower Eocene strata. Our findings also prove that subsurface fluid plumbing associated with the magmatic sills was prolonged in time and led to the development of several vertical fluid flow conduits, some of which triggered mass wasting in Neogene to Recent times. The repeated vertical expulsion of subsurface fluids weakened the strata on the continental slope, thereby promoting mass wasting, the selective cannibalization of the paleo-seafloor, and the formation of elongated craters at the basal shear zone of the mass-transport complex. Significantly, the model presented here proves a close link between subsurface magmatic plumbing systems and mass wasting on continental margins.</p

First evidence of (paleo)pockmarks in the Bass Strait, offshore SE Australia: A forced regression modulated shallow plumbing system

Pockmarks are morphological expressions of seabed fluid escape along continental margins. Identifying the underlying controls on their formation and spatial distribution is crucial for understanding substrate fluid plumbing systems and has important implications for hydrocarbon exploration, seafloor stability and seabed release of greenhouse gasses. Here, we use 3D seismic reflection dataset and a machine learning approach to present the first evidence for paleo-pockmarks in the Bass Strait, southeast Australia. The paleo-pockmarks are identified in the Bass Basin, within an interval between 250 and 310 m below present-day seafloor, corresponding to the Miocene carbonate-dominated Torquay Group. The paleo-pockmarks have depths ranging from ∼29 to 74 m and areas between ∼0.01 and 0.8 km2, with diameters varying between ∼0.1 and 1.1 km. The absence of an underlying seal-bypass system such as pipes and faults associated with these paleo-pockmarks discounts a deeper thermogenic source or a potential magmatic-driven fluid system. Rather a biogenic fluid system derived from the degradation of organic-rich layers and pore water expelled during early-stage compaction is hypothesised to drive paleo-pockmark formation. The seismic interval comprising these paleo-pockmarks demonstrates a distinctive seaward progradation and stepping-down configuration, indicating a forced regression. We propose this resulted in the destabilization of hydrostatic pressure triggering the creation of the paleo-pockmarks

Integrated 3D forward stratigraphic and petroleum system modeling of the Levant Basin, Eastern Mediterranean

International audienceThe Eastern Mediterranean Levant Basin is a proven hydrocarbon province with recent major gas discoveries. To date, no exploration wells targeted its northern part, in particular the Lebanese offshore. The present study assesses the tectono‐stratigraphic evolution and related petroleum systems of the northern Levant Basin via an integrated approach that combines stratigraphic forward modeling and petroleum systems/basin modeling based on the previous published work. Stratigraphic modeling results provide a best‐fit realisation of the basin‐scale sedimentary filling, from the post‐rift Upper Jurassic until the Pliocene. Simulation results suggest dominant eastern marginal and Arabian Plate sources for Cenozoic siliciclastic sediments and a significant contribution from the southern Nilotic source mostly from Lower Oligocene to Lower Miocene. Basin modeling results suggest the presence of a working thermogenic petroleum system with mature source rocks localised in the deeper offshore. The generated hydrocarbons migrated through the deep basin within Jurassic and Cretaceous permeable layers towards the Latakia Ridge in the north and the Levant margin and offshore topographic highs. Furthermore, the basin model indicates a possibly significant influence of salt deposition during Messinian salinity crisis on formation fluids. Ultimately, the proposed integrated workflow provides a powerful tool for the assessment of petroleum systems in underexplored areas