Abstract Onshore exposures of the North Atlantic Igneous Province have been studied in detail for over 200 years, whereas the more extensive offshore volcanic stratigraphy is significantly less well constrained with the exception of a small number of boreholes. Within this study we integrate seismic and well data across the northern Faroe–Shetland Basin and Møre Marginal High to improve understanding of the volcanic stratigraphy and its relationship to rifting in the NE Atlantic. Volcanic seismic facies, including compound and tabular lavas and hyaloclastites (representing subaerial and subaqueous emplacement), are interpreted across the study area, calibrated by the Lagavulin borehole. The volcanic sequence was erupted between c. 56.1 and 55.2 Ma, when subaerial conditions dominated in the region, but extensive lava deltas developed in a seaway east of the main lava field. Geochemical and thickness variations within the volcanic pile have important implications for the regional rifting history. MORB-like lavas at the base of Lagavulin, which thicken substantially northward, support an early onset of rifting near the Møre Marginal High prior to major thinning associated with continental breakup to the south and north. Following a period of erosion, smaller-degree melting caused the eruption of higher-TiO 2 /Zr lavas, marking the final ‘pre-breakup’ volcanism before emplacement of seaward-dipping reflectors.

ABSTRACT The geometry of collisional mountain belts, which were formed at the expense of passive continental margins, is often complex because orogenic structures, such as thrusts and related folds, commonly interfere with pre-orogenic extensional structures, namely, normal faults, resulting in kinematically complex, composite structural assemblages. In these settings, analysis of the relationships between depositional and structural features may provide very useful tools to correctly unravel the local sedimentary and deformational history and relative ages of structures. Analysis of the relationships between minor normal faults and slumps near Frontale in the Umbria-Marche Apennines of Italy made it possible to correctly unravel the local chronology of events and hence to infer the depositional and deformation history of a part of the Upper Cretaceous–Paleogene Scaglia Rossa Formation pelagic basin. The results of this investigation made it possible to ascribe the normal faults to events that predate the construction of the Umbria-Marche mountain belt. Therefore, the normal faults at Frontale are distinct from those that overprint the main compressional structures responsible for the present-day seismicity of central Italy.

ABSTRACT The Laptev Sea Rift in the East Siberian continental margin plays an important role in the geodynamic models for the opening of the Eurasia Basin. The active Gakkel Ridge, which also represents the boundary between the North America and Eurasia plates, abruptly meets the continental margin of the Laptev Sea. On the continental shelf in the prolongation of the Gakkel Ridge, a rift developed since the Late Cretaceous/Early Cenozoic with the formation of five roughly north-south trending depocenters. To better understand the evolution of this rift, a basin modeling study was carried out with PetroMod® software. The modeled sections used in this study were developed on the basis of depth-converted reflection seismic sections. The sections cover the Anisin Basin in the north and the southeastern margin of the Ust´ Lena Rift in the south. The numerical simulations are supported by tectonic and sedimentological field data that were collected in outcrops during the CASE 13 expedition to the New Siberian Islands in 2011. For the Anisin Basin different scenarios were modeled with rift onsets between 110 Ma and 66 Ma. The results show that the present-day temperature field in the area of the Anisin Basin and at the southeastern margin of the Ust´ Lena Rift is characterized by horizontal, seafloor-parallel isotherms. Geohistory curves extracted from the 2D simulations indicate a twofold rift evolution with a stronger initial subsidence in the Late Cretaceous to Early Paleogene and a moderate subsidence in Late Paleogene and Neogene times. Based on the modeling results, an early rift onset around 110 Ma seems to be more realistic than a later one around 66 Ma.

ABSTRACT In recent years, outcrop analogue studies have become a powerful tool in sedimentology for the assessment of reservoirs, both in hydrocarbon and aquifer studies. Data from exploratory drilling campaigns can be augmented significantly by observations on the outcrop of the corresponding stratigraphical interval with the objective to validate the borehole information through direct observation. In addition, through the physical separation of the outcrop area and the subsurface, the increased spatial coverage of a reservoir and its equivalents provides additional information about facies and their changes and thus on reservoir properties. This chapter presents results of a study on the Cretaceous sedimentary aquifers in Saudi Arabia (Wasia–Biyadh–Aruma) in order to better assess the storage volume of fossil ground-water, which is of fundamental importance for the hyper-arid kingdom. Besides the regional 3-D stratigraphic framework, the focus was on measurements of porosity and permeability of approximately 150 samples and the interpretation of reservoir quality in terms of sedimentary facies and its diagenetic overprint. In general, both porosity and permeability are varying on a high level (Biyadh: 1–36% / 2100–6500 mD; Wasia: 3–42% / 2100–6500 mD; Aruma: 1–38% / 10 –6 –0.15 Darcy). Apparently, the storage volume and hydraulics of these regional aquifers are controlled not only by their fracturing but also by their matrix porosity. Permeability varies by about an order of magnitude among samples or between vertical and horizontal permeability within some samples. This variation can be well explained by heterogeneity due to sedimentary facies, for example, cross-bedding and bioturbation. In some areas, the kind of cementation and its intensity have a large effect on the permeability. The data obtained enhance the quality of the hydraulic interpretations of this aquifer system. Spectral gamma-ray logs proved to be useful for a regional correlation and the correlation of aquifers and aquicludes. This is based on the recognition of the major unconformities in the logs but also on the identification of various paleosol horizons, which regularly show high emissions of U and Th radionuclides. Intensive weathering during the Cretaceous is responsible for dominantly kaolinitic clay mineralogy and consequently negligible K emissions.

ABSTRACT The structural evolution of the T-Block (U.K. 16/17) Brae Formation fields in the southern part of the South Viking Graben reflects a history of Late Jurassic rifting and Early Cretaceous inversion. Triassic rifting follows an inherited Caledonian trend, with Permian and Triassic depocenters to the northwest and southeast of a ridge trending north–northeast through the South Viking Graben from the area of the Thelma field. In the northern part of the area, in Trees Block (U.K. 16/12), halokinesis has created accommodation space for Middle Jurassic deposition. Further south, in T-Block, Middle Jurassic deposition does not appear to have been influenced by Caledonide structures. Rifting commenced in Trees Block in the early part of the Late Jurassic, with development of a north–south striking northern fault segment. The faulting propagated southward from the northern segment and northward from a segment to the south of T-Block, to create a relay zone opposite Thelma and Toni. At the segment centers, the fault throws are large, and the Middle Jurassic sequence dips to the west, toward the footwall. In comparison, at the Thelma relay zone, the fault displacements are much smaller, and the Middle Jurassic dips to the east. Flexural uplift and back-tilting have affected the footwall sediments and normal faults. The fault segment evolution is likely to have been a significant control on Brae sedimentation, the back-tilting of the footwalls at the segment centers funneling sediment supply into the Thelma relay zone, and footwall uplift providing emergent source areas adjacent to the developing graben. The basin morphology has been modified by postrifting thermal subsidence, increasing the eastward dip of the fault terraces. Inversion in the Early Cretaceous caused uplift of the hanging wall, creating a bulge over Thelma and Toni, and uplift on the fault adjacent to Trees Block. This inversion event is likely to be the result of oblique northwesterly compression, causing shortening and left-lateral strike-slip on the marginal faults. This event can be related to an unconformity between the Valhall and the Carrack formations, which constrains timing to the late Barremian–Aptian.