Description: This study focuses on the reservoir characteristics of a Permian tight gas field in the Southern Permian Basin, Eastern Frisia, Germany. To improve the understanding of the reservoir, 3D seismic, wireline and core data were compared with a reservoir analogue in the Panamint Valley, United States. Depositional environments of the Permian Upper Rotliegend II include perennial saline lakes, coastal parallel sand belts comprising wet, damp and dry sand flats and aeolian dunes with interdune deposits. Polygonal patterns at different scales were observed on seismic horizon slices in the reservoir intervals and the overlying Zechstein. Outlines of superordinate polygons coincide with interpreted faults. Similar polygonal networks were identified on modern dry lakes in the western United States. The kilometre-long, up to 1.20 m deep open fissures in the Panamint Valley are interpreted to originate from the combined effects of synaeresis and tectonics. Subsequently, the fissures were filled with aeolian sediment. Vegetation growth confined to the lineaments indicates enhanced fluid circulation. Such fissures systems may serve as weakness zones and fault grain and impact reservoir quality in terms of hydraulic connectivity of reservoir compartments. For the Rotliegend reservoirs, original porosities and permeabilities of these zones were reduced to a minimum by enhanced cementation along the fluid migration pathways. Permeability barriers and reservoir compartmentalization, which can be clearly depicted on seismic attribute volumes, are a potential result of this development.

Description: Comparison of modern deposits in the Panamint Valley, western United States, to core and geophysical data from a Permian (Rotliegend, Germany) tight gas field allows for improved understanding of the interaction of tectonics and sedimentary processes during Rotliegend deposition. The Panamint Valley was selected for a modern analog of the subsurface Rotliegend Basin because both study sites are characterized by (1) elongated grabens with large-scale bounding fault zones resulting from synsedimentary transtensional tectonics; (2) fault-controlled paleotopography as key controlling parameter for the sediment facies distribution, including alluvial fans, dunes, wet and damp interdune sandflats, and ephemeral dry lake deposits; and (3) local sediment provenance from sedimentary and volcanic rocks. The analysis of satellite images and field data from the Panamint Valley enabled the development of a conceptual model involving topography, synsedimentary faulting, and wind activity as controlling factors for the sediment facies distribution. The application of the model to the reconstructed Rotliegend paleotopography of the German subsurface study site allows for prediction of the facies distribution prior to the Triassic–Cretaceous tectonic overprinting. As a consequence, we expect a sediment facies succession from (1) alluvial fan deposits along the hanging walls of the basin-bounding fault zones to (2) distributary fluvial channel deposits toward the basin center and (3) ephemeral lake deposits in the deepest basin area. (4) Eolian dune accumulation and preservation is mainly concentrated on hanging-wall locations. However, additional dune deposits are proposed above overlapping step faults and on footwalls of synsedimentary active faults. (5) Sandflats occur on the upwind and downwind margins of the dune field. These predictions are calibrated to core and geophysical well log data.

Description: Petroleum systems located at passive continental margins received increasing attention in the last decade mainly because of deep- and ultra‐deep-water hydrocarbon exploration and production. The high risks associated with these settings originate mainly from the poor understanding of inherent geodynamic processes. The new priority program SAMPLE (South Atlantic Margin Processes and Links with onshore Evolution), established by the German Science Foundation in 2009 for a total duration of 6 years, addresses a number of open questions related to continental breakup and post‐breakup evolution of passive continental margins. 27 sub‐projects take advantage of the exceptional conditions of the South Atlantic as a prime “Geo‐archive.” The regional focus is set on the conjugate margins located east of Brazil and Argentina on one side and west of Angola, Namibia and South Africa on the other (Figure 1) as well as on the Walvis Ridge and the present‐day hotspot of Tristan da Cunha. The economic relevance of the program is demonstrated by support from several petroleum companies, but the main goal is research on fundamental processes behind the evolution of passive continental margins.

Description: Numerous studies have addressed various aspects of the East African Rift system but surprisingly few on the offshore continuation of the south-eastern branch of the rift into the Mozambique Channel. The most prominent article has been published almost 30 years ago by Mougenot et al. (1986) and is based on vintage seismic data. Several studies investigating earthquakes and plate motions from GPS measurements reveal recent deformation along the offshore branch of the East African Rift system. Slip vectors from earthquakes data in Mozambique’s offshore basins show a consistent NE direction. Fault plane solutions reveal ~ E-W extensional failure with focal depth clustering around 19 km and 40 km, respectively. Here, we present new evidence for neotectonic deformation derived from modern seismic reflection data and supported by additional geophysical data. The modern rift system obviously reactivates structures from the disintegration of eastern Gondwana. During the Jurassic/Cretaceous opening of the Somali and Mozambique Basins, Madagascar moved southwards along a major shear zone, to its present position. Since the Miocene, parts of the shear zone became reactivated and structurally overprinted by the East African rift system. The Kerimbas Graben offshore northern Mozambique is the most prominent manifestation of recent extensional deformation. Bathymetry data shows that it deepens northwards, with approximately 700 m downthrown on the eastern shoulder. The graben can be subdivided into four subbasins by crosscutting structural lineaments with a NW-SE trend. Together with the N-S striking graben-bounding faults, this resembles a conjugate fault system. In seismic reflection data normal faulting is distinct not only at the earthquake epicenters. The faults cut through the sedimentary successions and typically reach the seafloor, indicating ongoing recent deformation.

Description: We present a comprehensive regional bathymetric data compilation for the southwest Indian Ocean (swIOBC) covering the area from 4°S to 40°S and 20°E to 45°E with a spatial resolution of 250 m. For this, we used multibeam and singlebeam data as well as data from global bathymetric data compilations. We generated the swIOBC using an iterative approach of manual data cleaning and gridding, accounting for different data qualities and seamless integration of all different kinds of data. In comparison to existing bathymetric charts of this region, the new swIOBC benefits from nearly four times as many data-constrained grid cells and a higher resolution, and thus reveals formerly unseen seabed features. In the central Mozambique Basin a surprising variety of landscapes were discovered. They document a deep reaching influence of the Mozambique Current eddies. Details of the N-S trending Zambezi Channel could be imaged in the central Mozambique Basin. Maps are crucial not only for orientation but also to set scientific processes and local information in a spatial context. For most parts of the ocean seafloor, maps are derived from satellite data with only kilometer resolution. Acoustic depth measurements from ships provide more detailed seafloor information in tens to hundreds of meters resolution. For the southwest Indian Ocean, all available depth soundings from a variety of sources and institutes are combined in one coherent map. Thus, in areas where depth soundings exist, this map shows the seafloor in so-far unknown detail. This detailed map forms the base for subsequent studies of e.g. the direction of ocean currents, geological and biological processes in the southwest Indian Ocean.

Description: Numerous studies have addressed various aspects of the East African Rift system (EARS) but surprisingly few the offshore continuation of the south-eastern branch of the rift into the Mozambique Channel. Here, we present new evidence for neotectonic deformation derived from modern seismic reflection data and sup- ported by additional geophysical data. The Kerimbas Graben offshore northern Mozambique is the most prominent manifestation of sub-recent extensional deformation. The seismic reflection data reveals that recent normal faulting often utilizes preexisting, deeply buried half-graben structures which likely are related to the formation of the Somali Basin. The ca. 30 km wide and ca. 150 km long symmetric graben is in a stage where the linkage of scattered normal faults already did happen, resulting in increased displacement and accommodation of most of the extension across the basin. However, deep earthquakes below the rift indicate a strong and still preserved lithospheric mantle. Extension is becoming diffuse where an onshore suture, subdividing the northern from the southern metamorphic basement onshore Mozambique, is closest to the offshore rift. It appears likely that this suture is the origin for the variation in rifting style, indicating that mantle fabric resulting from a Cambrian collision has been preserved as mechanical anisotropy of the lithospheric mantle. Further south the rift focuses in an about 30 km wide half- graben. An important finding is that the entire offshore branch of the EARS lacks significant volcanism. Along the off- shore EARS there are only negligible indications for recent volcanism in the reflection seismic data such as sills and dikes. Apparently the "Comoros mantle plume" (French and Romanowicz, 2015) has a very minor influence on the progressive extensional deformation along the northern Mozambique continental margin, leading eventually to breakup sometimes in the future. Combining structural with earthquake data reveals that the magma-poor offshore rift is in a stage where mainly the lithospheric mantle is extended but not yet broken.