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<jats:title>Abstract</jats:title><jats:p>The Karkonosze-Izera Massif in the West Sudetes preserves evidence of subduction of the Saxothuringian Ocean beneath the Teplá-Barrandian Domain. Within the massif, the Leszczyniec metaigneous complex (LMC) is identified as the upper allochthon. It exhibits a unique structural history in comparison to the underlying allochthons, suggesting that the LMC records a distinctive tectonic history. To investigate the timing of this history, two orthogneisses were studied from a single outcrop of the LMC for in situ white mica Rb/Sr geochronology. The outcrop bears a southeast-dipping foliation (S1) and a north/northeast plunging stretching lineation (L1), defined by white mica and quartz. Quartz recrystallization textures, white mica chemistry (celadonite content of 0.23–0.47), preservation of igneous plagioclase phenocrysts, and the metamorphic mineral assemblage, all indicate maximum epidote–amphibolite facies conditions. Single-spot Rb/Sr dates were calculated from white mica using initial <jats:sup>87</jats:sup>Sr/<jats:sup>86</jats:sup>Sr values obtained by titanite and epidote. Results are similar for both rocks, providing weighted averages of 352.4 ± 4.1 Ma (MSWD: 0.6; n: 24) and 349.3 ± 2.5 Ma (MSWD: 0.4; n: 31). The rocks are interpreted to have the same structural and metamorphic history; thus, a pooled weighted average of 350.1 ± 5.3 Ma (2σ) is reported as the timing of white mica (re)crystallization during S1 and L1 development in epidote–amphibolite facies conditions. This event is bracketed by the timing of blueschist-facies metamorphism for the subjacent middle (c. 364 Ma) and lower (c. 345–341 Ma) allochthons, associated with an east/southeast-plunging L1. Considering the different structural and metamorphic histories of the LMC compared to the subjacent allochthons, it is likely that the complex was extracted from the Teplá-Barrandian upper plate due to subduction erosion prior to collective exhumation and stacking of the Karkonosze-Izera Massif.</jats:p> <jats:p><jats:bold>Graphical abstract</jats:bold></jats:p>

<jats:title>Abstract</jats:title><jats:p>In the 1990s and early 2000s, it was recognized that marine muds consisted of sortable silt (63–8 µm) and aggregated (&lt; 8 µm) particle suites and that these responded differentially to the hydraulic sorting process. Among the aggregated particle suite, the composition and hydraulic behavior of fecal pellets received the least attention. The present study focused on a tidal basin (~ 71 km<jats:sup>2</jats:sup>) of the East Frisian Wadden Sea (southern North Sea), in which the depositional patterns of both the sortable silt and aggregated mud fractions were compared with the aim of identifying similarities and/or dissimilarities. The results show essentially dissimilar trends, the sortable silt suite being characterized by two non-overlapping hydraulic populations, the aggregated particle suite by three overlapping populations with modal diameters separated by only a few microns. The depositional pattern of the latter is interpreted to suggest that the hydraulic populations relate to specific fecal pellet groups, each composed of a different discrete grain-size spectrum produced by different filter-feeding organisms. At the same time, it is demonstrated that the distribution of organic matter is closely linked to the aggregated (&lt; 8 µm) particle suite. The CaCO<jats:sub>3</jats:sub> content, by contrast, is linked to the mud fraction by a power relationship, the large data scatter suggesting multiple sources. Budget calculations show that the standing stock of mud in the uppermost 5 cm of the sediment in the tidal basin amounts to ~ 0.461 × 10<jats:sup>6</jats:sup> tons (9.78% of the total sediment), of which ~ 31.3 × 10<jats:sup>3</jats:sup> tons (0.67% of the total sediment) are contributed by organic matter.</jats:p> <jats:p><jats:bold>Graphical abstract</jats:bold></jats:p>

<jats:title>Abstract</jats:title><jats:p>Over the past few decades, Toarcian (Early Jurassic) black shale deposits of NW Europe have been extensively studied, and the possible global and regional mechanisms for their regional variation have been discussed. In this context, the black shales of the Northwest German Basin are still sparsely studied with regard to their palaeo-depositional history. This study aims to understand the connection between regional and global influences on the widespread Early Toarcian oceanic anoxic event by examining two wells covering the Upper Pliensbachian to Upper Toarcian sediments in the Northwestern German Basin. The core intervals were analysed using a multidisciplinary approach, including geochemistry, biostratigraphy and organic petrography. Marine palaeoenvironmental changes were reconstructed, and sediment sequences were stratigraphically classified to allow a supra-regional stratigraphic correlation. The results reveal complex interactions between sea level changes, climate warming, basin confinement, and Tethys–Arctic connectivity resulting in the Toarcian black shale deposition. Upper Pliensbachian sediments were deposited under terrigenous influence, shallow water depths, and predominantly oxic bottom water conditions. The deposition of black shale is characterized by algal organic material input and anoxic bottom water conditions. Strong correlations between water stratification, anoxia, and bioproductivity suggest that global warming and intensification of monsoonal rainfall, continental weathering, and increasing freshwater and nutrient inputs were the main factors controlling the formation of black shales. Prolonged deposition of OM-rich sediments in the NWGB may be related to intensified monsoonal precipitation in northern Europe and enhanced Tethys–Arctic connectivity at the <jats:italic>serpentinum–bifrons</jats:italic> transition.</jats:p> <jats:p><jats:bold>Graphical Abstract</jats:bold></jats:p>

<jats:title>Abstract</jats:title><jats:p>One of the most remarkable features of the central Northern Calcareous Alps (Eastern Alps, Austria) is the widespread presence of Upper Triassic deep-water carbonates (the Hallstatt facies) and Permo-Triassic evaporites resting on deep-water Middle Jurassic strata and their underlying Upper Triassic shallow-water carbonate platform successions. The Hallstatt facies and accompanying evaporites have been classically interpreted to originate either from a location south of the time-equivalent carbonate platforms, or to have been deposited in deeper water seaways within the broad platform domain. To date, this dispute has been addressed mostly through the analysis of Triassic and Jurassic facies distribution in map view, which, however, is subject to some degree of ambiguity and subjectivity. In this contribution we present, for the first time, sequentially restored regional cross-sections through the central Northern Calcareous Alps to understand the implications of the contrasting paleogeographic models. We present (a) an interpretation based on a highly allochthonous origin of the Triassic deep-water units and (b) an interpretation based on their relative autochthony in which we incorporate the potential influence of salt tectonics in the central NCA. The restored cross-sections provide a framework within which the alternative scenarios and their paleogeographic implications can be better understood. Through this analysis we propose that salt tectonics in the central NCA can provide a valid explanation for apparent inconsistencies in the relative autochthony scenario and thus constitutes a reasonable alternative to the currently accepted allochthony scenario.</jats:p> <jats:p><jats:bold>Graphical abstract</jats:bold></jats:p>

<jats:title>Abstract</jats:title><jats:p>Fieldwork provided well-preserved <jats:italic>Laevaptychus</jats:italic> sp. ex gr. <jats:italic>hoplisus</jats:italic>–<jats:italic>obliquus</jats:italic> specimens from the lower Kimmeridgian of Zengővárkony (Mecsek Mountains, south Hungary). This study presents the stable isotope analysis of these aptychi and control samples from brachiopods (<jats:italic>Nucleata</jats:italic> and <jats:italic>Pygope</jats:italic>) derived from the Zengővárkony section bed 3. Rarely observed structures in the upper lamellar layers of the studied laevaptychi revealed 24–32 concentric lamellae that represent primary textural features and indicate excellent preservation. After careful screening for diagenetic effects, stable oxygen isotope compositions yielded seawater temperatures between 20 and 26 °C in good agreement with earlier studies on Jurassic formations, with improved precision. Our research presents for the first time that well-preserved laevaptychi may be a reliable data source for paleoclimate and paleotemperature reconstructions.</jats:p> <jats:p><jats:bold>Graphical abstract</jats:bold></jats:p>