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Seismic-reflection data contain residual noise after processing, which can cause geologic misinterpretation of noise-sensitive seismic attributes. For detailed subsurface imaging, seismic data conditioning can enhance the visualization of subsurface reflection features down to the limit of seismic resolution. This study on the Gabes-Tripoli Basin of western offshore Libya demonstrates the potential of postprocessing seismic data conditioning using a standard industry 3D-seismic data set. The seismic data exhibit distinct reflection discontinuities and configurations interpreted as folds, reverse faults, and crustal- and gravity-driven normal faults. Other reflection discontinuities are interpreted as imaging the external form and internal architecture of buried carbonate platforms. The seismic-reflection interpretation finds that seismic data conditioning by filtering strongly supports the interpretation of the 3D geometry, type, and trend of distinct subsurface reflection features, particularly if used as input for a structural-attribute generation. Postprocessing seismic conditioning initially improved the signal-to-noise ratio by structure-oriented filtering with edge preservation. Application of this filter configuration emphasized subtle geologic features supporting, e.g., the detection of faults close to the limit of the seismic resolution. At the same time, the filtering resulted in a higher lateral continuity of the individual seismic reflectors, supporting the autotracking of the horizons. Structural attributes generated from the conditioned data such as the variance and curvature imaged more subsurface reflection detail when compared with the structural attributes generated from nonconditioned data. The filter-based workflow proposed can be applied in most seismic interpretation software packages and is recommended to be used as a standard procedure preceding a structure-attribute calculation and structural interpretation of the seismic-reflection data of limited quality.

In its subsurface, the Browse Basin on the Australian Northwest Shelf accommodates one of the largest Miocene–Pliocene carbonate platform provinces on Earth. This study presents a comprehensive three-dimensional (3-D) documentation and investigation of the Neogene Browse Basin carbonates based on the analysis of 15 3-D seismic reflection volumes covering ca. 33,000 km2 and 22 industry boreholes. Eight basin-wide seismic marker horizons tied to Sr isotope and biostratigraphic data provide a robust 3-D chronostratigraphic framework that (1) newly documents the occurrence of Miocene to recent carbonate systems in vast inboard basin areas; (2) presents the 3-D distribution and dynamic development of carbonate platforms through time constrained by absolute ages; and (3) supports the detailed 3-D interpretation of Miocene to recent depositional processes and key stratigraphic controls. Around 18.6 Ma, the extent of all Browse Basin carbonate platforms was ca. 8600 km2, rising to >10,000 km2 between 15.6 Ma and 12 Ma. By ca. 9.7 Ma, the total platform extent had decreased to ca. 5700 km2, waning to

The distal Andean foreland basin (Chaco-Pampean Plain) is thought to have been tectonically inactive during the Cenozoic. However, re-interpreted industry seismic reflection data, borehole information and gravity surveys document a rich and complex history of tectonic activity. Our new data synopsis and re-analysis reveals two, regionally extensive and approximately N-S oriented, basement highs beneath the flat present-day surface. The Quirquincho (or Rincón Caburé) and Pampeano-Chaqueño highs have been observed by previous authors, but the mechanism that elevated these features and the timing has remained elusive. Here, we discuss several viable mechanisms of their formation. The morphology, wavelength and stratal terminations suggest that the Quirquincho high could represent a forebulge due to Paleogene orogenic processes. In contrast, the Pampeano Chaqueño high farther east might correspond to a Neogene forebulge, implying forebulge migration. Alternatively, both highs could have been caused by blind and associated with a major crustal detachment. In this case these processes may have been facilitated by vertical mechanical strength contrasts in the foreland crust that have been invoked to drive spatially and temporally disparate thick-skinned deformation during the Andean orogeny. The fact that the arches occur in the vicinity of Cretaceous normal faults and rift basins suggests that these highs could also have been linked with extensional processes; in this case basement uplift and erosion would have been followed by sedimentary processes that finally caused the onlap of the Paleogene strata on the arches. Finally, we also consider the possibility they are Paleozoic, inherited features with posterior reactivation.

Journal of Asian earth sciences 232, 105126 (2022). doi:10.1016/j.jseaes.2022.105126 special issue: "Tectonics and Sedimentology of Accretionary and Collisional Orogens / Edited by Wenjiao Xiao, A.M. Celâl Sengor, Yucheng Chai, Songjian Ao, Dongfang Song", Published by Elsevier Science, Amsterdam [u.a.]

Pleistocene ice ages had a profound influence on the subsurface, in parts, until the present day. Ice masses during glacial advances partly covered onshore Netherlands during two glacial periods, the Elsterian and Saalian stages. This study presents a 3D basin and petroleum systems model of the northeastern Netherlands with implemented glacial stages to address the influence of low surface temperatures and the mechanical loading of ice sheets on the subsurface. Two ice sheet thickness scenarios were used to constrain results based on published ice sheet thickness estimates. Overall, Quaternary glacial stages substantially impact the temperature and pressure distribution in the subsurface. Subsurface temperatures are significantly reduced during glacial stages, leading to lowered present-day temperatures and a low geothermal gradient in the shallow subsurface. In deeply buried sedimentary formations, pressures build up with every glacial advance resulting in overpressures at the present day. Glacial stages do not directly influence the petroleum generation of petroleum source rocks in the area, but high pressures during loading might have impacted petroleum expulsion of the early mature Coevorden Formation. Hydrocarbon accumulations in the Lower Saxony Basin were simulated to investigate the possible effects of mechanical ice loading and unloading on hydrocarbon migration. A loss of Coevorden Formation-sourced hydrocarbons to the surface was calculated in the Lower Saxony Basin during the glacial stages, indicating an influence of glacial loading on the Mesozoic petroleum system.

Scientific reports 9(1), 18356 (2019). doi:10.1038/s41598-019-54981-7, Published by Macmillan Publishers Limited, part of Springer Nature, [London]

The presence of a set of well-known turbidite successions, deposited in progressively E-migrating foredeep basins and subsequently piled up with east vergence, makes the Northern Apennines of Italy paradigmatic of the evolution of deepwater fold-and-thrust belts. This study focuses on the early Apenninic collisional stage, early Miocene in age, which led to the accretion of the turbidites of the Trasimeno Tectonic Wedge (TTW), in the central part of the Northern Apennines. Based on the interpretation of previously unpublished seismic reflection profiles with new surface geology data and tectonic balancing, we present a detailed tectonic reconstruction of the TTW. In the study area, the TTW is characterized by a W-dipping shaly basal décollement located at a depth of 1–5 km. The tectonic wedge isc. 5 km thick at its central-western part and tapers progressively eastwards toc. 1 km. The total shortening, balanced along a 33 km long cross-section, isc. 60 km, including 20 km (40%) of internal imbrication,c. 23 km of horizontal ENE-wards translation along the basal décollement andc. 17 km of passive translation caused by the later shortening of footwall units. Deformation balancing, constrained through upper Aquitanian – upper Burdigalian (c. 21–16 Ma) biostratigraphy, provides an average shortening rate ofc. 8.6 mm a–1. Internal shortening of the TTW shows an average shortening rate ofc. 4 mm a–1for this period.

Sedimentology : the journal of the International Association of Sedimentologists (2021). doi:10.1111/sed.12948, Published by Wiley-Blackwell, Oxford

Polygonal faults are ubiquitous features, commonly observed in seismic images of fine-grained sedimentary successions along many passive margins. They are characterized by covering large parts of the basin with a typical polygonal pattern. In the last decade, different mechanical models for the generation of polygonal faults have been proposed; however, as they are commonly formed at depth and not directly observable at the surface, their formation remains a matter of debate. As part of the GEOTREF Program (ADEME – Investissement d’avenir) we found polygonal fault structures exposed close to the surface in marine soft sediments at 5 m water depth at the western coast of Guadeloupe. The structures are associated with fault-bound thermal springs and clearly visible at the sea bottom due to preferential precipitation of sulfur minerals and concentration of diatoms. In a multidisciplinary study involving a team of hydrogeologists, marine micro-biologists, and structural geologists, we study the genesis of polygonal faults in this setting. We analyzed the sediments in which the polygonal faults formed structurally and geochemically. First results suggest that SiO2 precipitated from hydrothermal fluids increases the cohesion of the most permeable soft sediments. Dewatering of the underlying layers causes the formation of polygonal faults at a depth of

Three-dimensional (3D) seismic-reflection analysis of a major Miocene-to-Pleistocene (c. 19–2 Ma) clinoform succession of the central Taranaki Basin offshore New Zealand reveals two distinct intervals of downbuilding progradation (c. 7.5–6 Ma; and c. 4–2 Ma). Downbuilding clinoforms are of kilometre scale and characterized by straight upper foreset gullies that initiate near or at the clinoform breakpoint, in places connected to topset distributary channels. Foreset mass-transport complexes occur mainly in the basal parts of downbuilding clinoform successions. Upbuilding progradational clinoforms formed between c. 6–5.5 Ma and c. 4.5–4 Ma. These clinoforms are generally smaller, with topsets in places comprising beach ridges and tidal channels. The foresets of the upbuilding clinoforms contain large gullies and sinuous deepwater channels, locally connected to topset channels. Retrogradational deposits in the studied succession (c. 5.5–4.5 Ma) lack a distinct clinoform geometry, show a few slope channels and gullies, and are characterized by extensive landward-stepping networks of shallow-marine and fluvial channels. 3D seismic-reflection analysis of the c. 2000 km2 study area allows an exemplary 3D documentation of migrating depositional systems along a highly progradational clastic margin, constrained by a stratigraphic framework tightly defined by the two intervals of major depositional downbuilding. The Late Miocene downbuilding is interpreted as forced by tectonic uplift along the Cape Egmont fault and neighbouring structures in the south of the study area. In contrast, the Plio-Pleistocene downbuilding is interpreted as dominantly controlled by eustasy in a tectonic environment characterized by subsidence. Excellent preservation of the 4–2 Ma clinoform topsets provides unique insights into depositional systems at and above the shelf break imaging palaeo-shoreline and palaeo-backshore environments. The detailed 3D clinoform analyses presented contribute to the understanding of clastic sedimentation processes from shelf to slope, which can be used to predict deepwater depositional facies.

Syn-sedimentary deformation and submarine channel initiation are both important processes influencing the stratigraphic development and reservoir properties of carbonate platforms. Based on a high-resolution 3D seismic dataset our study shows that platform-margin parallel syn-sedimentary faulting in the vicinity of the clinoform breakpoint can lead to the indention of channel heads that subsequently grow and expand in headward and downslope direction. The carbonate-dominated Miocene succession of the Browse Basin on the Australian North West Shelf reveals a distinct submarine channel system during a time of overall platform progradation. The progradation occurs over a drowned Eocene to Lower Miocene carbonate ramp, which formed a large scale inflection. Previous studies investigated the architecture of the carbonate platform, containing a large Neogene barrier reef system. We present a high-resolution 3D seismic study of the contemporaneous platform to slope transition. Landward of first significant gullies, a distinct network of margin parallel, small scale arcuate faults is observed. Active faulting during appearance of the first gullies is exhibited by growth strata, which are located directly basinward of the faults. These steep (65°–85°), small-scale faults are characterized by throws of 5–25 ms TWT and show a tendency to merge laterally and vertically with adjacent faults. Syn-sedimentary deformation associated with these faults likely triggered slope failure and the generation of turbidity currents finally leading to the growth of the gullies by headward and downslope erosion.

This study presents a regional comparison between selected 2D seismic transects from large, conjugated salt and salt-free basins offshore southern Brazil (Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Kwanza Basin, northern and southern Namibe Basin, Walvis Basin). Tectonic-stratigraphic interpretation of the main rift and post-rift units, free-air gravity data and flexural isostatic backstripping were used for a comprehensive basin-to-basin documentation of key mechanisms controlling the present-day differences in conjugated and neighbouring South Atlantic basins. A significant variation in the tectonic-sedimentary architecture along-strike at each margin and between the conjugated basins across the South Atlantic reflects major differences in (1) the structural configuration of each margin segment at transitional phase between rifting and breakup, as emphasized in the highly asymmetric settings of the large Santos salt basin and the conjugated, salt-free southern Namibe Basin, (2) the post-breakup subsidence and uplift history of the respective margin segment, which caused major differences for example between the Campos and Espirito Santo basins and the conjugated northern Namibe and Kwanza basins, (3) variations in the quantity and distribution of post-breakup margin sediments, which led to major differences in the subsidence history and the related present-day basin architecture, for example in the initially rather symmetric, siliciclastic Pelotas and Walvis basins, and (4) the deposition of Aptian evaporites in the large rift and sag basin provinces north of the Rio Grande Rise and Walvis Ridge, highly contrasting the siliciclastic basins along the margin segments south of the ridges. The resulting present-day architecture of the basins can be generally classified as (i) moderately symmetric, salt-free, and magma-rich in the northern part of the southern segment, (i) highly asymmetric, salt-bearing and magma-poor vs. salt-free and magma-rich in the southern part of the central segment, and (iii) moderately symmetric to asymmetric, salt-rich, and magma-poor in the central part of the central segment of the South Atlantic.

Extensive 2D and 3D seismic-reflection data calibrated by wells provide new insights into the lateral extent, morphology, internal architecture, and age of carbonate platforms in the subsurface of the Browse Basin, Australian Northwest Shelf (NWS). The oldest carbonate build-ups are interpreted as a giant bryozoan build-up complex of Oligocene age (34.03–27.8 Ma). In the late Burdigalian, tropical reef growth began, and numerous reef-rimmed carbonate platforms progressively coalesced into an extensive barrier reef. From the mid-Langhian to the early Tortonian, the Browse Basin contained an elongate (along-margin) barrier-reef system over 500 km long. This barrier reef possibly extended in the southwest into the Northern Carnarvon Basin. After the early Tortonian, reefs on top or landward of this major barrier-reef system were smaller and less connected. This significant reduction in area covered by reef-rimmed platforms likely resulted from cooling following the Mid-Miocene Climate Optimum and relatively high subsidence rates. The reef-rimmed carbonate platforms that formed between the late Burdigalian and the early Tortonian are very similar throughout the Browse Basin. Platform development after the early Tortonian was regionally diverse. High subsidence rates in the northern Browse Basin are interpreted to have promoted the development of thick, aggrading platforms. Lower subsidence in the south led to thinner, more widespread platforms, recurrently shifting location in response to eustatic change. The final phase of reef decline around 6 Ma coincides with an increase in current-driven drift sedimentation. Current-related winnowing of sediments from the lagoons and slopes of the remaining carbonate platforms likely contributed to their final drowning.

The modern seafloor of the Australian Northwest Shelf between Exmouth and Dampier was analyzed for large scale sedimentary bedforms on 3D seismic reflection data. The Carnarvon MegaSurvey of Petroleum Geo-Services (PGS), a merged dataset of multiple industrial 3D seismic reflection surveys with a total size of 49,717 km2, offers an extensive view of the continental shelf, slope and rise of the Northern Carnarvon Basin. Over the shelf two fields of large scale sediment waves were observed in water depths between 55–130 m, where the seafloor may be influenced by different processes including internal waves, tides and storms. Based on the dimensions and orientations of the sediment waves the dominant direction and approximate strength of local bottom currents could be estimated. Information on local sediment grain-size distribution was provided by the auSEABED database allowing a classification of the observed sediment waves into sand- or mudwaves. The first sediment wave field is positioned northwest of the Montebello Islands where the shelf is comparatively narrow and local sediment is mainly sand-sized. It most likely formed by increased bottom currents induced by the diversion of tidal flows around the islands. The second sediment wave field is located north of the Serrurier and Bessieres Islands within a local seafloor depression. Local sediments are poorly sorted, containing significant amounts of mud and gravel in addition to the mainly sand-sized grains. The coarser sediment fraction could have been reworked to sandwaves by cyclone-induced bottom currents. Alternatively, the finer sediment fraction could form mudwaves shaped by less energetic along-slope oriented currents in the topographic depression. The sediment waves consist partially of carbonate grains such as ooids and peloids that formed in shallow water during initial stages of the post glacial sea-level rise. These stranded carbonate grains thus formed in a different environment than the sediment waves in which they were redeposited. In fossil examples of similar high-energy ramp systems this possible out-of-equilibrium relationship between grains and bedforms has to be taken into account for the interpretation of the depositional environment.

s & presentations : EGU General Assembly 2020 EGU General Assembly 2020, EGU2020, online, 4 May 2020 - 8 May 2020; Göttingen : Copernicus Gesellschaft mbH EGU2020-21627, 1 Seite (2020). doi:10.5194/egusphere-egu2020-21627, Published by Copernicus Gesellschaft mbH, Göttingen

The Gabes-Tripoli Basin of western offshore Libya encompasses and neighbours several large hydrocarbon fields (e.g. the Bouri Field with 1000-3000 Million barrels oil), which are of major economic importance for Libya. Despite the relevance and value of the basin, there are today several unsolved geological questions concerning the basin's late Cretaceous to recent tectonic development; the role of a potential Triassic salt substratum influencing the development of hydrocarbon-bearing anticlines; and the interaction of tectonics and sedimentation controlling reservoir-rock deposition, reservoir fracturing, hydrocarbon migration and accumulation. This study presents detailed structural-stratigraphic interpretations of the Gabes-Tripoli Basin based on 3D-seismic-reflection data and borehole information. A workflow is used that is specifically designed to enhance the seismic interpretability of faults. The workflow integrates targeted 3D-seismic data pre-conditioning, volume-attribute analysis and isochore (TWT) interpretation. Detailed 3D subsurface attribute interpretations show that (i) different groups of faults with different structural orientation characterize the different stratigraphic intervals between the Late Cretaceous and today; (ii) major anticlines associated with the main hydrocarbon reservoirs trend WSW-ENE and SSE-NNW, which is oblique to the dominant NW-SE fault trend. The SSE-NNW-oriented anticlines present a newly documented fold orientation in the basin; (iii) large N-S oriented, gravity-driven, synsedimentary listric normal faults formed at the edges of major anticlines bounding kilometre-scale sedimentary depocentres; and (iv) Paleogene anticline growth and growth faulting at the anticline edges was decoupled from the dominant Late Cretaceous to recent NW-SE-oriented, deep-rooted crustal fault trend. Combined tectonic and stratigraphic interpretation documents partial decoupling of Eocene to Oligocene overburden faulting in the western and central study area from otherwise basement-rooted strike-slip tectonics. Lateral and vertical subsurface evaporite movement in the Paleogene is regarded as an important control for anticline growth and reservoir development in anticline crests, with contemporaneous and subsequent basement-involved strike-slip faulting contributing to a high variability in fault- and fracture-trends and types.

In the past two decades, numerical forward modeling of petroleum systems has been extensively used in exploration geology. However, modeling of petroleum systems influenced by magmatic activity has not been a common practice, because it is often associated with additional uncertainties and thus is a high risk associated with exploration. Subsurface processes associated with volcanic activity extensively influence all the elements of petroleum systems and may have positive and negative effects on hydrocarbon formation and accumulation. This study integrates 3D seismic data, geochemical and well data to build detailed 1D and 3D models of the Kora Volcano&mdash, a buried Miocene arc volcano in the northern Taranaki Basin, New Zealand. It examines the impact of magmatism on the source rock maturation and burial history in the northern Taranaki Basin. The Kora field contains a sub-commercial oil accumulation in volcanoclastic rocks that has been encountered by a well drilled on the flank of the volcano. By comparing the results of distinct models, we concluded that magmatic activity had a local effect on the thermal regime in the study area and resulted in rapid thermal maturation of the surrounding organic matter-rich sediments. Scenarios of the magmatic activity age (18, 11 and 8 Ma) show that the re-equilibration of the temperature after intrusion takes longer (up to 5 Ma) in the scenarios with a younger emplacement age (8 Ma) due to an added insulation effect of the thicker overburden. Results of the modeling also suggest that most hydrocarbons expelled from the source rock during this magmatic event escaped to the surface due to the absence of a proper seal rock at that time.

Journal of structural geology 118, 210-223 (2019). doi:10.1016/j.jsg.2018.10.011, Published by Elsevier Science, Amsterdam [u.a.]

After Mesozoic rifting, the Atlantic margin of Morocco has recorded the consequences of the continental collision between Africa and Europe and the relative northward motion of the African plate over the Canary Island hotspot during Cenozoic times. Interpretation of recently acquired 2D seismic reflection data (MIRROR 2011 experiment) presents new insights into the Late Cretaceous to recent geodynamic evolution of this margin. Crustal uplift presumably started during the Late Cretaceous and triggered regional tilting in the deep-water margin west of Essaouira and the formation of the Base Tertiary Unconformity (BTU). An associated hiatus in sedimentation is interpreted to have started earlier in the north (presumably in the Cenomanian at well location DSDP 416) and propagated to the south (presumably in the Coniacian at well location DSDP 415). The difference in the total duration of this hiatus is postulated to have controlled the extrusion of Late Triassic to Early Jurassic salt during the Late Cretaceous to Early Palaeocene non-depositional period, resulting in regional differences in the preservation of salt structures: the Agadir Basin in the south of the study area is dominated by salt diapirs, whereas massive canopies characterised the Ras Tafelnay Plateau farther north and salt-poor canopies and weld structures the northernmost offshore Essaouira and Safi Basins. Accompanied by volcanic intrusions, a presumably Early Palaeogene reactivation of previously existing basement faults is interpreted to have formed a series of deep-water anticlines with associated gravity deformation of shallow-seated sediments. The orientation of the fold axes is roughly perpendicular to the present day coast and the extensional fault direction; therefore, not a coast-line parallel pattern of extensional faults, related to the rifting and break-up of the margin, but rather a coast-line perpendicular oceanic fracture zone might have caused the basement faults associated with the deep-water folds. Both the volcanic intrusions and the formation of the deep-water anticlines show a comparable age trend which gets progressively younger towards the south. A potential tempo-spatial relationship of the BTU and the reactivation of basement faults can be explained by the relative northward motion of the African plate over the Canary Island hotspot. Regional uplift producing the BTU could have been the precursor of the approaching hotspot during the Late Cretaceous, followed during the Early Palaeogene by a locally more pronounced uplift above the hotspot centre.

Three dimensional seismic-reflection data from the western Niger Delta were used to investigate the segmentation and linkage of a syn-sedimentary normal fault array and to estimate the influence of a pre-existing normal fault on the geometry and growth of younger faults. The nucleation, growth and linkage of a regional (seaward-dipping) deltaic fault system were analyzed on reflectivity time-/horizon slices and vertical seismic sections. In the deep subsurface, a master fault that consists of two segments (northwestern, NW, and southeastern, SE) grew through time into a single fault by lateral tip propagation reaching a final length of about 15 km. After attaining this length, displacement along the fault system developed non-uniformly through time. The analysis of the hanging-wall sediments of the deep-seated master fault shows two different processes of vertical linkage above the NW and SE segment. The SE segment links vertically to several younger faults contemporaneously with displacement accumulation on the master fault; in contrast, fault linkage above the NW segment occurred only after an interval of master-fault inactivity connecting the deep-seated structure upwards to a single syn-sedimentary normal fault. The observed differences in fault development suggest that although multi-segment deltaic faults form single fault systems after segment linkage, individual pre-linkage characteristics can be preserved, supporting a possibly diverse upward growth and connection to younger faults in the overburden. The geological interpretations presented highlight the influence of large deep-rooted structures on the development, location and geometry of shallow deltaic faults, documenting the influence of an older structural grain on delta tectonics.

The Miocene sedimentary succession of the southern Browse Basin records the response of a tropical reef system to long-term, strong subsidence on a passive continental margin. Geological interpretation of a comprehensive two-dimensional (2D) seismic reflectivity data set documents for the first time the development of a continuous Miocene barrier reef on the Australian North West Shelf. With a length of over 250 km, this barrier reef is among the Earth’s largest in the Neogene record. A sequence stratigraphic analysis tied to well data shows that the main controls for the evolution, growth and demise of the reef system were subsidence, third-order global-scale eustatic variations and antecedent topography. The generally very high Miocene subsidence rates estimated for the study area cannot be explained by typical passive-margin subsidence controlled by lithospheric cooling and sedimentary loading alone. Additional dynamic subsidence induced by mantle convection, though documented as unusually large on the northern margin of Australia during the Neogene, can be also regarded as being of only minor importance. Therefore, accelerated tectonic subsidence related to the collision of the Australian and Eurasian Plates 250–500 km north of the study area seems to exert an important influence on reef development and demise, complicated by local tectonic inversion. The Miocene tectonic reactivation and inversion of an older structural grain is interpreted to have controlled the reef development considerably by providing localized topographic highs along transpressional anticlines above basement-rooted faults that served as preferential sites for reef growth and retreat during times of rapidly rising sea level. This exemplarily shows that the far-field effects of collision-induced tectonic subsidence can significantly influence carbonate systems on passive margins.

Three-dimensional seismic data and wireline logs from the western Niger Delta were analyzed to reveal the sedimentary and tectonic history of a major deltaic growth-fault depocenter comprising a kilometer-scale rollover anticline. The seismic units of the rollover show a non-uniform thickness distribution with their respective maximum near the main bounding growth-fault on the landward side of the system. This wedge-shaped sediment-storage architecture ultimately reflects the non-uniform creation of accommodation space in the study area that was controlled by 1) the differential compaction of the hanging-wall and footwall strata, 2) the lateral variation of fault-induced tectonic subsidence above the listric master fault, and possibly 3) local subsidence related to the subsurface movement of mobile shale reacting to loading and buoyancy. A sequential three-dimensional decompaction of the interpreted deltaic rollover units allowed to reconstruct and measure the compaction development of the rollover succession through time, documenting that sediment compaction contributed per depositional interval to between 25 and 35% of the generation of depositional space subsequently filled by deltaic sediments. The incremental decompaction of sedimentary units was further used to quantify the cumulative amount of accommodation space at and around the studied rollover that was created by fault movement, shale withdrawal, regional tectonic subsidence, isostasy and changes in sea level. If data on the regional subsidence and eustasy are available, the contribution of these basinwide controls to the generation of depositional space can be subtracted from the cumulative accommodation balance, which ultimately quantifies the amount of space for sediments to accumulate created by fault movement or shale withdrawal. This observation is important in that it implies that background knowledge on subsidence, stratigraphic age and sea-level changes allows to reconstruct and quantify fault movement in syn-tectonic deltaic growth successions, and this solely based on hanging-wall isopach trends independent of footwall information.

We present a 64-channel cross-correlator system for space-borne synthetic aperture imaging. Two different types of ASICs were developed to fit into this system: An 8-channel comparator ASIC implemented in a 130 nm SiGe BiCMOS process technology performs A/D conversion, while a single 64-channel digital cross-correlator ASIC implemented in a 65 nm CMOS process performs the signal processing. The digital ASIC handles 2016 cross-correlations at up to 3.6 GS/s and has a power dissipation of only 0.13 mW/correlation/GHz at a supply voltage of 1 V. The comparator ASIC can handle sample rates of at least 4.5 GS/s with a power dissipation of 47 mW/channel or 1 GS/s with a power dissipation of 17 mW/channel. The assembled system consists of a single board measuring a mere 136 x 136 mm(2) and weighing only 135 g. The assembled system demonstrates crosstalk of 0.04% between neighboring channels and stability of 800 s. We provide ASIC and system-board measurement results that demonstrate that aperture synthesis can be a viable approach for Earth observation from a geostationary Earth orbit.

This study analyses the three-dimensional geometry of sedimentary features recorded on the modern sea floor and in the shallow subsurface of a shelf to upper slope region offshore Australia that is characterized by a pronounced internal wave regime. The data interpreted comprise an extensive, >12 500 km2 industrial three-dimensional seismic-reflection survey that images the northern part of the Browse Basin, Australian North West Shelf. The most prominent seismic–morphological features on the modern sea floor are submarine terrace escarpments, fault-scarps and incised channels, as well as restricted areas of seismic distortion interpreted as mass wasting deposits. Besides these kilometre-scale sea floor irregularities, smaller bedforms were discovered also, including a multitude of sediment waves with a lateral extent of several kilometres and heights up to 10 m. These sedimentological features generally occur in extensive fields in water depths below 250 m mostly at the foot of submerged terraces, along the scarps of modern faults and along the shelf break between the outer shelf and the upper continental rise. Additional bedforms that characterize the more planar regions of the outer shelf are elongate, north-west/south-east oriented furrows and ridges. The formation of both sediment waves and furrow-ridge systems requires flow velocities between 0·3 m sec−1 and 1·5 m sec−1, which could be generated by oceanic currents, gravity currents or internal waves. In the studied setting, these velocities can be best explained as being generated by bottom currents induced by internal waves, an interpretation that is discussed against oceanographic background data and modelling results. In addition to the documentation of three-dimensional seismic–geomorphological features of the modern sea floor, it was also possible to map kilometre-scale buried sediment wave fields in the seismic volume down to ca 500 ms two-way-time below the present sea floor, indicating the general potential for the preservation of such bedforms in the sedimentary record.

Three-dimensional (3D) seismic data from the southern Danish North Sea were used to analyse the morphology and spatial distribution of depressions in the Danian Chalk deposit. Previously, these depressions were either interpreted as karst structures or pockmarks. The observed depressions occur in an interval from 25 ms below to 12 ms above the Top Chalk surface. Three types of depressions were differentiated based on their plan-view geometry and their degree of symmetry: Type 1, comprising sub-circular and symmetrical depressions, is the dominant group (ca. 70 %). Type 2, elongated and symmetrical depressions, represents only a small fraction (ca. 5 %). The elongated and asymmetrical depressions of Type 3 compose ca. 25 %. In cross section, each depression type can be either characterised by a V- or a U-shape. The maximum size of the depressions ranges from 50 to 580 m, with an average internal depth of 10 m. We interpret the depressions as pockmarks formed by the expulsion of biogenic or thermogenic fluids at the Danian seafloor. Likely, the initial form of the pockmarks has been circular (Type 1) and was subsequently modified for Types 2 and 3 to an elongated form by currents. The long axis of the pockmarks is interpreted to represent the effective current direction. The inferred direction is sub-parallel to the palaeobathymetric contours. The 3D seismic interpretation of pockmarks presented in this paper contributes to the understanding of fluid migration and palaeocirculation patterns during the sedimentation of the terminal Chalk Group in the southern Danish North Sea.

This study presents a reconstruction of the tectonic history of an Upper Rotliegend tight gas field in Northern Germany. Tectonism of the greater study area was influenced by multiple phases of salt movement, which produced a variety of salt-related structural features such as salt walls, salt diapirs as well as salt glaciers (namakiers). A sequential 2D retro-deformation and stratal backstripping methodology was used to differentiate mechanisms inducing salt movement and to discuss their relation to regional tectonics. The quantitative geometric restoration included sedimentary balancing, decompaction, fault-related deformation, salt movement, thermal subsidence, and isostasy to unravel the post-depositional tectonic overprint of the Rotliegend reservoir rock. The results of this study indicate that reactive salt diapirism started during an Early Triassic interval of thin-skinned extensional tectonics, followed by an active diapirism stage with an overburden salt piercement in the Late Triassic, and finally a period of intensive salt surface extrusion and the formation of salt glaciers (namakiers) in Late Triassic and Jurassic times. Since the Early Cretaceous, salt in the study area has been rising by passive diapirism.

The County Council's board for new therapies (the NT Council) provides recommendations on the use of new drugs based on the ethical platform of priorities, founded by the Swedish parliament. The Council has formulated a policy that interprets the parliamentary ethical platform and operationalize its need and solidarity principle and cost effectiveness principle in four dimensions. The NT Council weighs the health economic evaluation of the drug and the four dimensions: the severity of the condition, the rarity of the condition, the effect size and the data reliability to determine the willingness to pay level and whether the platform allows a recommendation for using of the drug. The severity of the condition has a greater impact than the other dimensions. In the assessment of severity there is also a trade-off between prevention and treatment of manifest diseases and in prevention, the size of the risk of falling ill is of importance. A slightly higher willingness to pay level is reasonable for treatment of very rare conditions, but it is important that identified patients are not given priority over anonymous patient groups with equally strong needs.

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.

This study examines eight syndepositional faults and syntectonic sediments in five major fault blocks in western Niger Delta, offshore Nigeria, on three-dimensional seismic data. The initiation, lateral growth and retreat, periods of activity and quiescence, and decay of faulting around these blocks can be ascertained by analyzing a series of time-structure and isopach maps. The study area can be subdivided into three structural zones. The first structural zone is a northwestern zone characterized by a major counterregional growth fault in the deep subsurface. This deep-seated structure is superposed by an array of younger regional growth faults displacing a kilometer-thick sedimentary overburden that accumulated on the former footwall. The second structural zone is a central to eastern zone that seems mostly unaffected by young deltaic faulting. This zone is characterized by the thinnest sedimentary record of the study area. The third structural zone is a southeastern zone that is dominated by a large, listric, backstepping master fault zone associated with a kilometer-scale rollover system. Regional structural and stratigraphic analyses document an apparently strong relationship between syntectonic sedimentation and syndepositional fault activity in that phases of significant fault activity, lateral fault growth, and fault migration concur with major depositional phases; in turn, areas and intervals characterized by the least sediment accumulation also record the lowest fault activity. However, one particularity of the studied system is that it underwent at least one period of seaward fault progression that coincided with a backstepping of faulting on the landward side. Although the forward stepping of faulting near the delta front can be interpreted as the consequence of the progressive loading during delta progradation, the contemporaneous backstepping of faulting further inboard likely reflects the sustained lateral growth of mature deltaic faults into previously undeformed proximal parts of the depocenter. The results of this study, thus, document that although an apparent correlation with the superimposed depositional system exists on a regional scale, inboard deltaic faults may persist to grow irrespective of sedimentary loading. The recognition of such fault trends is particularly important for estimating the influence of late-stage fault movement on hydrocarbon migration or the discovery of subtle fault-controlled hanging-wall reservoirs.

In recent years, tight gas reservoirs have received increased exploration interest as new technological developments such as horizontal drilling and hydraulic fracturing simplify tight gas exploitation. The term “tight gas reservoir” is not uniformly defined. Law and Curtis [1] defined low permeability sandstone reservoirs as those exhibiting permeabilities