Rift-related paleogeography of the European margin in the Eastern Alps (Central Tauern Window)

Continent-derived tectonic units in the Tauern Window of the Alps exhibit stratigraphic and structural traces of extension of continental margins eventually leading to the opening of the Alpine Tethys. In this study, we reassess lithostratigraphic data from the central part of the Tauern Window to reconstruct the post-Variscan evolution of this area, particularly the rift-related geometry of the European continental margin. The lithostratigraphy of the Alpine nappes reflects systematic variations of the structure of the European margin. The lowest tectonic units (Venediger nappe system, Eclogite Zone and Trögereck Nappe) are characterized by a thick succession of arkose-rich Bündnerschiefer-type sediments of probably Early Cretaceous age that we interpret as syn-rift sequence and which stratigraphically overlies thinned continental basement and thin pre-rift sediments. In contrast, the highest tectonic unit derived from Europe (Rote Wand Nappe) preserves a thick pre-rift sedimentary sequence overlying thinned continental basement, as well as a thick syn- to post-rift succession characterized by turbiditic Bündnerschiefer-type sediments of probable Cretaceous age. These observations point towards a highly segmented structure of the European rifted margin. We propose that this involved the formation of an outer margin high, partly preserved in the Rote Wand Nappe, that was separated from the main part of the European margin by a rift basin overlying strongly-thinned continental crust. The along-strike discontinuity of the Rote Wand Nappe is proposed to reflect the lateral variation in thickness of the outer margin high that resulted from margin-parallel segmentation of the European continental crust during highly oblique rifting antecedent to the opening of Alpine Tethys

Evolution of a Fossil Subduction Zone: Insights from the Tauern Window, Eastern Alps

Subduction zones play a crucial role in the evolution of Earth's lithosphere. In many orogens, deeply subducted coherent high-pressure (HP) nappes were exhumed from deep to shallow parts of subduction channels. This process significantly affects the deformation pattern and internal structure of the orogen. Exhumation seems to occur preferentially during the transition from subduction to collision, when dense oceanic lithosphere has been consumed entirely and more buoyant continental lithosphere from a passive continental margin enters the subduction zone. Here, we present a detailed study on the structural, kinematic, and metamorphic evolution of a well-preserved paleo-subduction channel within the Tauern Window (Alps). First, we reevaluated the metamorphic history and regional tectono-stratigraphy of the tectonic units in the central Tauern Window. These units originate from the Alpine Tethys oceanic domain and the adjacent European passive continental margin. They experienced HP conditions during Alpine subduction, which was followed by exhumation to their current position in the Alpine nappe stack. By integrating new structural data and the well-preserved stratigraphy of the ocean-continent transition, we reconstructed the structure and kinematics of the nappes in great detail. Notably, we document a recumbent, tens-of-kilometers-scale sheath fold formed during pervasive top-to-the-foreland shear. This sheath fold comprises an isoclinally folded thrust that transported ophiolite relicts from the former Alpine Tethys onto a distal part of the European continental margin during early stages of subduction. It formed under HP conditions, immediately after the Europe-derived rocks in its core reached their maximum burial depth. The non-cylindrical shape of the sheath fold suggests its nucleation at a promontory of the former margin, inherited from Mesozoic rifting and subsequently amplified to a sheath geometry during top-to-the-foreland shear in the subduction zone. To gain insight into the temperature (T) structure of the sheath fold, we employed Raman spectroscopy on carbonaceous material (RSCM) thermometry on a large number of samples with high spatial resolution. The systematic spatial temperature trends reveal distinct domains related to the original subduction metamorphism and later T-dominated (Barrovian) metamorphic overprint. Integrating the peak-temperature pattern with the fold geometry unveils a two-stage process of nappe formation and sheath folding during exhumation. Our results highlight the existence of considerable along-strike heterogeneity within the deep portion of a fossil subduction zone, likely influenced by inherited rift structures and exhumation processes. Understanding such heterogeneities is crucial for interpreting seismic sections and numerical simulations of subduction zones, emphasizing the need to consider three-dimensional complexities beyond the idealized cylindrical models often used. By unraveling the structural and metamorphic evolution of exhumed HP nappes in the Tauern Window, this study contributes to a better understanding of the dynamic processes operating within subduction zones and their implications for mountain building

Evolving temperature field in a fossil subduction channel during the transition from subduction to collision (Tauern Window, Eastern Alps)

We investigate the evolution of the three-dimensional thermal structure of a palaeo-subduction channel exposed in the Penninic units of the central Tauern Window (Eastern Alps). Structural and petrological observations reveal a sheath fold with an amplitude of some 20 km that formed under high-Pconditions (similar to 2 GPa). The fold is a composite structure that isoclinally folded the thrust of an ophiolitic nappe derived from Alpine Tethys Ocean onto a unit of the distal European continental margin, also affected by the high-Pconditions. This structural assemblage is preserved between two younger domes at either end of the Tauern Window. The domes deform isograds of theT-dominated Barrovian metamorphism that itself overprints the high-Pmetamorphism partly preserved in the sheath fold. Using Raman spectroscopy on carbonaceous material (RSCM), we are able to distinguish peak-temperature domains related to the original subduction metamorphism from domains associated with the later temperature-dominated (Barrovian) metamorphism. The distribution of RSCM temperatures in the Barrovian domain indicates a lateral and vertical decrease of peak temperature with increasing distance from the centres of the thermal domes. This represents a downward increase of palaeo-temperature, in line with previous studies. However, we observe the opposite palaeo-temperature trend in the lower limb of the sheath fold, namely an upward increase. We interpret this inverted palaeo-temperature domain as the relic of a subduction-related temperature field. Towards the central part of the sheath fold's upper limb, RSCM temperatures increase to a maximum of similar to 520 degrees C. Further upsection in the hangingwall of the sheath fold, palaeo-peak temperatures decrease to where they are indistinguishable from the peak temperatures of the overprinting Barrovian metamorphism. Peak-temperature contours of the subduction-related metamorphism are oriented roughly parallel to the folded nappe contacts and lithological layering. The contours close towards the northern, western and eastern parts of the fold, resulting in an eye-shaped, concentric pattern in cross-section. The temperature contour geometry therefore mimics the fold geometry itself, indicating that these contours were also folded in a sheath-like manner. We propose that this sheath-like pattern is the result of a two-stage process that reflects a change of the mode of nappe formation in the subduction zone from thrusting to fold nappe formation. First, thrusting of a hot oceanic nappe onto a colder continental nappe created an inverted peak-thermal gradient. Second, sheath folding of this composite nappe structure together with the previously established peak-temperature pattern during exhumation. This pattern was preserved because temperatures decreased during retrograde exhumation metamorphism and remained less than the subduction-related peak temperatures during the later Barrovian overprint. The fold ascended with diapir-like kinematics in the subduction channel

Observation of Chirality‐Induced Roton‐Like Dispersion in a 3D Micropolar Elastic Metamaterial

A theoretical paper based on chiral micropolar effective-medium theory suggested the possibility of unusual roton-like acoustical-phonon dispersion relations in 3D elastic materials. Here, as a first novelty, the corresponding inverse problem is solved, that is, a specific 3D chiral elastic metamaterial structure is designed, the behavior of which follows this effective-medium description. The metamaterial structure is based on a simple-cubic lattice of cubes, each of which not only has three translational but also three rotational degrees of freedom. The additional rotational degrees of freedom are crucial within micropolar elasticity. The cubes and their degrees of freedom are coupled by a chiral network of slender rods. As a second novelty, this complex metamaterial is manufactured in polymer form by 3D laser printing and its behavior is characterized experimentally by phonon-band-structure measurements. The results of these measurements, microstructure finite-element calculations, and solutions of micropolar effective-medium theory are in good agreement. The roton-like dispersion behavior of the lowest phonon branch results from two aspects. First, chirality splits the transverse acoustical branches as well as the transverse optical branches. Second, chirality leads to an ultrastrong coupling and hybridization of chiral acoustical and optical phonons at finite wavevectors

Tnfaip2/exoc3 ‐driven lipid metabolism is essential for stem cell differentiation and organ homeostasis

Abstract Lipid metabolism influences stem cell maintenance and differentiation but genetic factors that control these processes remain to be delineated. Here, we identify Tnfaip2 as an inhibitor of reprogramming of mouse fibroblasts into induced pluripotent stem cells. Tnfaip2 knockout impairs differentiation of embryonic stem cells (ESCs), and knockdown of the planarian para‐ortholog, Smed‐exoc3 , abrogates in vivo tissue homeostasis and regeneration—processes that are driven by somatic stem cells. When stimulated to differentiate, Tnfaip2 ‐deficient ESCs fail to induce synthesis of cellular triacylglycerol (TAG) and lipid droplets (LD) coinciding with reduced expression of vimentin ( Vim )—a known inducer of LD formation. Smed‐exoc3 depletion also causes a strong reduction of TAGs in planarians. The study shows that Tnfaip2 acts epistatically with and upstream of Vim in impairing cellular reprogramming. Supplementing palmitic acid (PA) and palmitoyl‐L‐carnitine (the mobilized form of PA) restores the differentiation capacity of Tnfaip2 ‐deficient ESCs and organ maintenance in Smed‐exoc3 ‐depleted planarians. Together, these results identify a novel role of Tnfaip2 and exoc3 in controlling lipid metabolism, which is essential for ESC differentiation and planarian organ maintenance

Dectin-2 is a Syk-coupled pattern recognition receptor crucial for Th17 responses to fungal infection

Innate immune cells detect pathogens via pattern recognition receptors (PRRs), which signal for initiation of immune responses to infection. Studies with Dectin-1, a PRR for fungi, have defined a novel innate signaling pathway involving Syk kinase and the adaptor CARD9, which is critical for inducing Th17 responses to fungal infection. We show that another C-type lectin, Dectin-2, also signals via Syk and CARD9, and contributes to dendritic cell (DC) activation by fungal particles. Unlike Dectin-1, Dectin-2 couples to Syk indirectly, through association with the FcRγ chain. In a model of Candida albicans infection, blockade of Dectin-2 did not affect innate immune resistance but abrogated Candida-specific T cell production of IL-17 and, in combination with the absence of Dectin-1, decreased Th1 responses to the organism. Thus, Dectin-2 constitutes a major fungal PRR that can couple to the Syk–CARD9 innate signaling pathway to activate DCs and regulate adaptive immune responses to fungal infection

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Strukturelle, metamorphe und geodynamische Aspekte der Bildung von Zungenfaltendecken (Rote-Wand-Decke, Tauernfenster, Ostalpen)

The Tauern Window is the largest tectonic window of the Alps. It contains relics of the subduction channel that formed during Cenozoic subduction of the Alpine Tethyan Ocean and the European margin below the Adriatic plate. This thesis documents the structural, kinematic and metamorphic evolution of a segment of this subduction channel exposed in the central Tauern Window. The thesis presents new structural data that document a tens-of-kilometers-scale recumbent sheath fold in the center of the Tauern Window. The fold comprises an isoclinally folded thrust that transported relicts of the former Alpine Tethys (Glockner Nappe s. str.) onto a distal part of the former European continental margin (Rote Wand Nappe). New petrologic data indicate that the fold formed during early stages of exhumation from maximum burial depth at high-pressure conditions (ca. 2 GPa, 500 ◦C). Exhumation of the fold to mid-crustal levels is evidenced by near-isothermal decompression to roughly 1 GPa. The fold ascended in the subduction channel between two contemporaneous opposite-sense shear zones; normal-sense (i. e., top-hinterland) at the top of the fold and thrust-sense (i. e., top-foreland) below. The subduction-related thermal structure of the sheath fold was constrained by Raman spectroscopy on carbonaceous matter (RSCM) thermometry. The greatest peak-temperature conditions are located in the center of the fold at the folded ocean-on-continent thrust. The peak-temperature contours are oriented roughly parallel to the folded nappe contact so that they display a sheath-like pattern that mimics the geometry of the sheath fold itself. This pattern indicates that finite strain during sheath-fold formation decreased laterally from the fold’s center. Thus, together with the contemporaneous vertical strain gradients, the fold was shaped at least initially by diapir-like kinematics during exhumation. Lithostratigraphic correlation of the tectonic units in the central Tauern Window that derive from the European margin documents intense, rift-related segmentation of the margin. The Rote Wand Nappe, which is part of the sheath fold, probably originates from an extensional allochthon that was separated from the main margin by an extensive rift basin above strongly thinned continental basement. Here it is proposed that this extensional allochthon, when subducted, caused a perturbation of the flow field in the subduction channel. In line with sheath-fold theory, this caused strain localisation at the extensional allochthon, facilitating its initial diapiric ascent to form a proto-sheath fold. While being further exhumed by the normal-sense shear zone at its top, the rest of the fold was amplified in overall, thrust-sense simple-shear to a pronounced sheath-fold geometry. This model and above observations are compatible with forced channel flow as driving force of the upward-directed flow. This study shows how large structures inherited from rifting — e. g., extensional allochthons — could potentially induce perturbation of flow in subduction channels during the subduction of distal continental margins. Such perturbations can lead to complex kinematics in subduction channels and result in highly non-cylindrical nappes. Further investigation of similar scenarios could contribute to a better understanding of subduction zone dynamics during the transition from oceanic subduction to continent collision

Rift-related paleogeography of the European margin in the Eastern Alps (Central Tauern Window)

Abstract Continent-derived tectonic units in the Tauern Window of the Alps exhibit stratigraphic and structural traces of extension of continental margins eventually leading to the opening of the Alpine Tethys. In this study, we reassess lithostratigraphic data from the central part of the Tauern Window to reconstruct the post-Variscan evolution of this area, particularly the rift-related geometry of the European continental margin. The lithostratigraphy of the Alpine nappes reflects systematic variations of the structure of the European margin. The lowest tectonic units (Venediger nappe system, Eclogite Zone and Trögereck Nappe) are characterized by a thick succession of arkose-rich Bündnerschiefer-type sediments of probably Early Cretaceous age that we interpret as syn-rift sequence and which stratigraphically overlies thinned continental basement and thin pre-rift sediments. In contrast, the highest tectonic unit derived from Europe (Rote Wand Nappe) preserves a thick pre-rift sedimentary sequence overlying thinned continental basement, as well as a thick syn- to post-rift succession characterized by turbiditic Bündnerschiefer-type sediments of probable Cretaceous age. These observations point towards a highly segmented structure of the European rifted margin. We propose that this involved the formation of an outer margin high, partly preserved in the Rote Wand Nappe, that was separated from the main part of the European margin by a rift basin overlying strongly-thinned continental crust. The along-strike discontinuity of the Rote Wand Nappe is proposed to reflect the lateral variation in thickness of the outer margin high that resulted from margin-parallel segmentation of the European continental crust during highly oblique rifting antecedent to the opening of Alpine Tethys

Method for the Assessment of Potential in Distribution Logistics

Besides in production – where optimization is often used- also optimization of distribution logistics has a great potential for increasing competitiveness of companies. When searching for optimization, also in the distribution logistics numerous interactions must be considered. Companies have to search for the potentials of improvement with as little expenditure as possible and weigh them. For the assessment of the potentials, companies require an adequate method. Hence, in this paper a description of the demand for research will be given as well as an outline of the procedure for development of a suitable method which can be performed quickly and with reasonable expenditure and which considers the interactions