Abstract. The Ligurian Basin is located in the Mediterranean Sea to the north-west of Corsica at the transition from the Western Alpine orogen to the Apennine system and was generated by the south-eastward trench retreat of the Apennines–Calabrian subduction zone. Late-Oligocene-to-Miocene rifting caused continental extension and subsidence, leading to the opening of the basin. Yet it remains unclear if rifting caused continental break-up and seafloor spreading. To reveal its lithospheric architecture, we acquired a 130 km long seismic refraction and wide-angle reflection profile in the Ligurian Basin. The seismic line was recorded in the framework of SPP2017 4D-MB, a Priority Programme of the German Research Foundation (DFG) and the German component of the European AlpArray initiative, and trends in a NE–SW direction at the centre of the Ligurian Basin, roughly parallel to the French coastline. The seismic data were recorded on the newly developed GEOLOG recorder, designed at GEOMAR, and are dominated by sedimentary refractions and show mantle Pn arrivals at offsets of up to 70 km and a very prominent wide-angle Mohorovičić discontinuity (Moho) reflection. The main features share several characteristics (e.g. offset range, continuity) generally associated with continental settings rather than documenting oceanic crust emplaced by seafloor spreading. Seismic tomography results are complemented by gravity data and yield a ∼ 6–8 km thick sedimentary cover and the seismic Moho at 11–13 km depth below the sea surface. Our study reveals that the oceanic domain does not extend as far north as previously assumed. Whether Oligocene–Miocene extension led to extremely thinned continental crust or exhumed subcontinental mantle remains unclear. A low grade of mantle serpentinisation indicates a high rate of syn-rift sedimentation. However, rifting failed before oceanic spreading was initiated, and continental crust thickens towards the NE within the northern Ligurian Basin.

The limits of seaward spreading and slope instability at the continental margin offshore Mt Etna, imaged by highresolution 2D seismic data, Tectonophysics (2015Tectonophysics ( ), doi: 10.1016Tectonophysics ( /j.tecto.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T -Analysis of a combined new high-resolution 2D seismic and bathymetric data set offshore Mt Etna -Extensional domains are mapped at the shallow subsurface of the continental margin -Compressional structures are mapped at the toe of the continental margin ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 -A coupled volcano edifice / continental margin instability is proposed Mt Etna. The submarine realm is characterized by different blocks, which are controlled by local-and regional tectonics. A compressional regime is found at the toe of the continental margin, which is bound to a complex basin system. Both, the clear link between on-and offshore tectonic structures as well as the compressional regime at the easternmost flank edge, indicate a continental margin gravitational collapse as well as spreading to be present at Mt Etna. Moreover, we find evidence for the offshore southern boundary of the moving flank, which is identified as a right lateral oblique fault north of Catania Canyon. Our findings suggest a coupled volcano edifice / continental margin instability at Mt Etna, demonstrating first order linkage between on-and offshore tectonic processes. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

[1] Seismic investigations across the convergent Sunda margin off Indonesia provide a detailed image of the crustal architecture of the Sunda plate boundary. The combined analysis and interpretation of wide-angle and reflection seismic data along two coincident profiles across the subduction zone are complemented by additional lines within the forearc domain, which yield some three-dimensional (3-D) constraints on the velocity-depth structure across the margin. A detailed cross section of the subduction zone is presented, which is confirmed by supplementary gravity modeling. The Sunda convergence zone is a prime example of an accretionary margin, where sediment accretion has led to the formation of a massive accretionary prism, with a total width of >110 km between the trench and the forearc basin. It is composed of a frontal wedge which documents ongoing accretion and a fossil part behind the present backstop structure which constitutes the outer high. Moderate seismic velocities derived from wide-angle modeling indicate a sedimentary composition of the outer high. The subducting oceanic slab is traced to a depth of almost 30 km underneath the accretionary prism. The adjacent forearc domain is characterized by a pronounced morphological basin which is underlain by a layer of increased seismic velocities and a shallow upper plate Moho at 16 km depth. We speculate that remnant fragments of oceanic crust might be involved in the formation of this oceanic-type crust found at the leading edge of the upper plate beneath the forearc basin.

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In der Tiefsee ist die letzte Eiszeit noch nicht vorbeiGashydratvorkommen im Schwarzen Meer reagieren auf postglaziale Klimaänderungen 30.03.2021/Kiel/Bremen. Bei der Untersuchung von Gashydratvorkommen im westlichen Schwarzen Meer machte ein Team von Forschenden vom GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel und dem MARUM -Zentrum für Marine Umweltwissenschaften der Universität Bremen überraschende Entdeckungen. Entgegen bisheriger Erkenntnisse und Theorien fanden die Wissenschaftler*innen freies Methangas in Schichten, wo diese eigentlich nicht auftauchen dürften. In der jetzt in der internationalen Fachzeitschrift Earth and Planetary Science Letters veröffentlichten Studie schließen sie, dass sich das Gashydratsystem im Tiefseefächer der Donau durch die Klimaänderungen seit dem letzten glazialen Maximums weiterhin verändert.