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Hydrogen is expected to play a key role in decarbonising industry and storing energy from intermittent sources such as wind energy. Underground salt caverns are an attractive target for storage due to large volumes and effective sealing capacity. Despite ambitious goals to become a world-leader in hydrogen, there are no onshore salt basins in Scotland. Therefore, the offshore Forth Approaches Basin (FAB), currently undergoing development of the Seagreen wind farm, could provide a critical storage site. Re-evaluation of petrophysical data from five legacy hydrocarbon wells allowed an updated assessment of the composition and variability of the Late Permian Zechstein evaporite sequence. Well analysis is combined with seismic interpretation to understand the salt bodies and their suitability for solution mining. Three halite formations are identified: (1) The Stassfurt Halite which has insufficient thickness for solution mining; (2) The Leine Halite that comprises three sub-units with a KCl-dominated unit separating two halite-dominated units; (3) The Aller Halite only identified in the centre of the FAB. Where halokinesis has occurred, the Leine Halite reaches sufficient thicknesses (>300m) and purity for salt cavern placement, however heterogeneities are challenging to predict. Layered evaporites only reach sufficient thickness where the Aller Halite is present and could be developed with the underlying Leine Halite. Heterogeneities can be correlated across wells within the layered sequences aiding prediction. A strong understanding of evaporite facies distribution is required to ensure halite bodies are suitable for safe and economic solution mining in the FAB and other salt basins globally. Thematic collection: This article is part of the Hydrogen as a future energy source collection available at: https://www.lyellcollection.org/topic/collections/hydrogen

The analysis of downstream changes in ancient fluvial systems can better inform depositional models for foreland-basin systems. Herein we analyze the basal deposits of the Early Cretaceous Cedar Mountain Formation of Utah to better understand the variety of fluvial deposits present and to develop a depositional model for the Sevier foreland basin. We also evaluate the long-held interpretation of a braided origin for these deposits and document numerous examples of point-bar deposition in highly sinuous meandering rivers by analysis of large (20 to 60 km2) plan-view exposures. These plan-view exposures allow comparisons between planform and cross-sectional geometries. The study utilizes outcrop data, virtual outcrop models, and satellite imagery to develop a facies model and analyze the architecture of channel bodies in the Buckhorn Conglomerate and Poison Strip Sandstone of the Cedar Mountain Formation. We document downstream (west to east) decreases in lateral channel migration, sinuosity, channel amalgamation, grain size, and percent of fluvial channel facies (conglomerate and sandstone). Fluvial channel deposits occur arranged into larger stratal bodies: multistory–multilateral channel bodies that are dominantly composed of clast-supported conglomerate in the west to a mix of multistory, multilateral, and isolated channel bodies composed of matrix-supported conglomerate in the east. The median width of highly sinuous point bars is similar across the field area (344 m to 477 m), but the inclusion of narrower (median = 174 m), low-sinuosity bar elements in the east indicates an overall reduction in lateral channel migration and sinuosity downstream. Net-to-gross values range from 100% in much of the western outcrops to as low as 38% in the east. Paleocurrent analysis reveals a transverse (west to east) paleoflow for the study interval that merges with axial (south–north) paleoflow near the Utah–Colorado state line. We estimate 104 m3/s-scale discharge and 106 kilometer-scale drainage area for axial rivers based on paleohydraulic analysis which represents a significant part of the Early Cretaceous continental-scale drainage. The observed downstream trends in lateral channel migration, sinuosity, channel amalgamation, grain size, and net-to-gross for the basal Cedar Mountain Formation are consistent with expected trends for sinuous single-thread distributive fluvial systems and are similar to observed trends in the Jurassic Morrison Formation. Medial (Buckhorn Conglomerate) to distal (Poison Strip Sandstone) zones are preserved and span the forebulge to backbulge depozones of a foreland-basin system. Postulated deposits of the proximal distributive fluvial system have been removed during erosion of the foredeep depozone. The easternmost Poison Strip Sandstone and coeval Burro Canyon Formation represent deposits of an axial system at which western-sourced distributive fluvial systems end. Distributive fluvial systems dominate modern foreland basins, and this study suggests that they may constitute a significant proportion of ancient successions.

[Stratigraphic forward models can reproduce distributive fluvial systems at spatial and temporal scale. The model allows full parameter control and sampling coverage with computer capacity as the only limiting factor. Key finding was that lateral variability is greatest at the transition between the proximal and distal zone. , Abstract To better understand the stratigraphic development of sedimentary systems, it is necessary to link the controls on sedimentary processes to the resulting deposits, which in turn allows predictions of stratigraphic architectures at a range of scales. We use a stratigraphic forward model to link the governing parameters to the distribution of deposits within a distributive fluvial system (DFS). The numerical model has been validated against outcrop observations to establish how the depositional processes needed to form the specific sedimentary system have been reproduced. We chose the previously studied Oligocene to Miocene Huesca DFS in northern Spain to investigate and calibrate the model. Additionally, downstream profiles from modern DFS in northern India, and hydrological measurements from the High Island Creek, Minnesota, USA, were used as input parameters for the model in addition to the outcrop data from the Huesca DFS. The resulting model adequately reproduced the real‐world system. Once validated, the analysis of the modelled DFS led to key findings, which expand our understanding of DFS stratigraphic architecture. Reservoir characteristics in radial DFS are dependent on the angle away from the meridian (straight line from the source through the apex to the distal zone of the DFS). The greater the angle is, the coarser the average grain size in the proximal zone is but the finer the average grain size in the medial and distal zones. Lateral variability of net to gross, sandbody thickness and number, and amalgamation ratio is greatest at the transition between the proximal and medial zone and is still significant in the distal part of the DFS. Stratigraphic forward modelling enhanced our understanding of DFS, which leads to reducing risk associated with exploration, production and storage of fluids in subsurface DFS.]

ACKNOWLEDGEMENTS This work was funded by the SAFARI group. We are deeply grateful to Joe Phillips, Sean Kelly, James Mullins, Ryan King and Jostein Myking Kjaerefjord for help in the field. We would also like to thank Associate Editor, Christopher Fielding, for handling the review of this paper. Additionally we thank reviewers Benjamin Cardenas and Brian Currie for their comments and suggested revisions which have greatly enhanced this paper. Open Access via the Jisc Wiley Agreement

Volcanism in large igneous provinces (LIPs) is understood to have had the potential to affect global environments and ecosystems, triggering mass extinctions, climate change, and ocean acidification. However, basin-scale studies sediment distribution and sedimentary-system development in LIP lava fields are sparse and often limited to localized exposure. To gain a better understanding of the controls on inter-lava sedimentology across a continental LIP, a new sedimentological data set is presented from the Miocene Columbia River Flood Basalt Province (CRBP), situated in the Columbia Basin in south-central Washington State, northeast Oregon and eastern Idaho. Based on the qualification and quantification of sedimentary facies, petrography, paleoflow, channel dimensions, and catchment size from 96 sites across the Columbia Basin, a refined model of regional and local environmental change, integrating local volcanic and tectonic evolution, is presented. Here, CRBP stratigraphy is divided into six distinctive sedimentation intervals, which allows correlation of sedimentary interbeds formed in the western part and in the eastern part of the basin. The model describes and reviews drainage-system development and discusses the control of volcanic and tectonic activity on sediment distribution in the CRBP lava field at local to basin scale. The data presented here largely support findings of previous works suggesting a highly complex interplay between sedimentary, volcanic, and tectonic evolution of the area. In addition, it elaborates on the aspects of sediment–lava interaction and indicates that individual sub-basins in the CRBP formed separated depositional settings, emphasizing the lateral complexity of inter-lava sedimentation. Importantly, this work improves our understanding of sediment–lava relationships in continental LIPs and helps in building more generic models for sediment distribution in volcanic terranes where exposure is limited or absent.

Thin tidal estuarine deposits of the Naturita Formation (0–23 m) of the San Rafael Swell record the initial flooding of the Cretaceous Western Interior Seaway, Utah, and capture the transition from inland fluvial systems to fully marine conditions over a time period of 5 My or less. A tide-dominated estuarine environment is favored due to the combined presence of mud and/or carbonaceous drapes on ripples and dunes, bidirectional flow indicators, sigmoidal cross-stratification, herring-bone cross-stratification, and bimodal paleocurrent measurements. Facies associations are arranged in a predictable manner. Locally at the base of the Naturita Formation, tidally influenced fluvial channel deposits are present. These are overlain by tidal bars, including subtidal bars and intertidal point bars. Overlying the tidal bars are sand-flat and mud-flat deposits as well as bedded coal and carbonaceous mudstone that represents a supratidal setting in the estuary. The Formation can be capped by a thin transgressive lag composed of shell debris, and/or pebbles, that marks the final transition into the fully marine Tununk Shale Member of the overlying Mancos Shale.Lateral relationships between estuaries and adjacent paleohighs shed light on the influence of foreland-basin tectonics on the location and preservation of tide-dominated estuaries. Estuarine and shoreface deposits are absent along the eastern flank of the San Rafael Swell and eastward for more than 80 km. This zone of nondeposition or erosion is coincident with the location of the forebulge in the developing foreland basin, implying that growth of the forebulge prohibited the development of, or enhanced the later erosion of, estuarine deposits. Conversely, enhanced accommodation in the transition into the foredeep depozone allow the preservation of tide-dominated estuarine deposits along the western flank of the San Rafael Swell. Additionally, the possibility of a pre-Laramide tectonic history for the San Rafael Swell is indicated by a distinct lack of Naturita Formation deposits in an area that is coincident with the modern-day axis of the anticline.Overall, the Naturita records the initial flooding of the Western Interior Seaway in the San Rafael Swell region and provides an excellent case study of the deposits that are laid down in a transgressive system that passes from coastal-plain to offshore deposits.

[A new tectonic and depositional model is presented for the Lower Old Red Sandstone of the northern Midland Valley Basin—consolidating new and existing sedimentological data—reconstructing a large foreland basin DFS that records the time‐period between the late phases of the Caledonian Orogeny and the onset of post‐orogenic collapse in the mid‐Devonian , Abstract Reconstruction of the geological history of orogenic events can be challenging where basins have limited and/or fragmentary preservation. Here, we apply understanding gained from modern analogues to the sedimentological analysis of the succession of Upper Silurian to Lower Devonian Lower Old Red Sandstone (LORS), northern Midland Valley, Scotland, in order to reconstruct the foreland to the Caledonian orogeny. A new depositional model is presented which differs significantly from current understanding. Using facies analysis, grain size distribution and palaeocurrent data a large distributive fluvial system is reconstructed. Three lithofacies and nine sublithofacies are identified, forming fluvial channel and floodplain facies associations. The system was derived from an emerging mountain range in the Caledonian foreland undergoing constant tectonic rejuvenation to produce 9 km of coarse‐grained sediment, exhibiting an overall decrease in thickness towards the west and a large‐scale downstream reduction in grain size. Conglomerate sublithofacies dominate proximal areas in the east where amalgamated fluvial channel facies association is abundant, with a downstream increase in the dominance of floodplain facies. Additionally, observed grain size cyclicity is attributed to a pulsatory tectonic influence. The LORS records the time‐period between the late phases of the Caledonian Orogeny and the onset of post‐orogenic collapse in the mid‐Devonian and the presented model allows improved understanding of the north‐Atlantic Caledonian foreland.]

Stratigraphy, depositional facies and proximal-distal position within a depositional system are identified as controls on reservoir quality and dynamic reservoir performance in the Triassic, fluvial-dominated, Skagerrak Formation reservoirs of the UK and Norwegian Central North Sea. Core sedimentological analysis from across the basin links decreasing trends of channel facies proportion and channel package thickness with increasing floodplain and splay facies proportions and their respective package thicknesses. These trends are considered to represent the proximal to distal transitions of distributive fluvial systems. Depositional facies are shown to strongly control static and theoretical dynamic reservoir quality using porosity–permeability cross-plots and stratigraphically modified Lorenz plots using conventional core plug data. This linkage of stratigraphy, depositional system position, facies proportions and package thicknesses with static and theoretical dynamic reservoir performance is used to predict pressure-depletion profiles in various settings of Triassic reservoirs of the Central North Sea beyond major areas of well and field control in UK Quads 22 and 30.

As turbidity currents are sensitive to the geometry of the substrate across which they flow, the sedimentology of turbidites can chart the development of submarine structures and reveal regional palaeobathymetric connections. This rationale is applied to understand the tectonic evolution of the central Mediterranean in the early Miocene, using the African-sourced, hyper-mature Numidian sandstones and their immature, orogen-derived time-equivalents. In both Sicily and the southern Apennines, the Numidian sequence displays characteristics of confined–uncontained turbidites: grain-size breaks and coarse bedload indicative of ubiquitous flow bypass; short-range grain-size fractionation across flow; stacked sandy bed-sets in the flow axes. We reconstruct sand fairways for over 300 km across the region and propose that their causative flows, axially fed from north Africa, were confined along sinuous corridors created by active submarine thrusting. In contrast, orogen-derived turbidites (e.g. Reitano flysch, confined–contained turbidites) were ponded in mini-basins higher on the thrust wedge. The composite Apennine–Calabrian–Maghrebian orogen with its submarine thrust belt had occluded deep-water Tethyan connections through the central Mediterranean by early Miocene times. Palaeobathymetry across the submarine thrust belt increased northwards into the future Apennines. This study illustrates the utility of turbidite sedimentology, especially reconstructing sand fairways, in building palaeogeographical reconstructions of complex tectonic regimes.

A dropstone horizon is described from lake deposits in a palaeo-valley from the c. 1000 Ma Diabaig Formation, Torridon Group, NW Scotland. Dropstones occur in wave-rippled, fine-grained sandstones and siltstones that contain desiccation and syneresis cracks indicative of fluctuating lake levels. Five locally derived dropstones occur at the same horizon over lateral distance of 250 m and display clear evidence of deflection and penetration of laminae at the base, with thinning, onlap and draping of laminae on to clast margins and tops. Mechanisms of dropstone formation are discussed, with ice-rafting considered the most likely explanation. It is suggested that rafting was promoted by cold winters at 35° S in the early Neoproterozoic, possibly in an upland setting. Interpretation of the dropstones as ice-rafted debris provides the first physical record of evidence for ice at the Earth9s surface during the late Mesoproterozoic to early Neoproterozoic.

The Triassic sediments of the Central North Sea (CNS) are considered to have been deposited in a continental environment under a semi-arid climate. The Skagerrak Formation in particular, comprises an alternation of sandstone and mudstone members, the development of which is considered to be climatically driven. However, conflicting models exist as to how climate influences member deposition. Here we analyse the climatic signal using a multivariate statistical approach in which de-trended correspondence analysis (DCA) is applied to palynological observations to quantify environmental reconstruction. Using DCA it has been possible to define paleoecological groups and construct a relative hydrological state trend showing hydrological conditions within the centre of the CNS basin during the Triassic. The resultant trends reveal that the relationship between hydrological conditions in the basin and the development of individual sandstones and mudstone members is perhaps not a simple as indicated by existing models. In particular our data suggest that whilst influenced by broader climate trends, in the basin centre, there is no simple relationship between climate change and sandstone/mudstone development. The data also indicates that the Julius and Jonathan mudstone members were deposited under differing hydrological conditions. The DCA trends shown here also suggest that the Carnian Pluvial Episode (CPE) documented from the South Permian Basin and Tethys is not expressed in the CNS.

Virtual geological fieldtrips have become increasingly popular over the last decade, with the advent of remote piloted vehicles (RPVs; drones) leading to progressively sophisticated photorealistic virtual outcrops (VOs). As the COVID-19 pandemic led to widespread international travel restrictions, virtual fieldtrips (VFTs) became practical, and necessary substitutes for traditional fieldtrips. This contribution explores two VFTs delivered to a master’s level Petroleum Geoscience course at the University of Aberdeen, normally run as traditional fieldtrips to the Spanish Pyrenees and Utah. The paper describes the delivery of these VFTs and examines student perception, gauged primarily through questionnaires. The VFTs were run in LIME, a software specifically designed for the interpretation of 3D models and the delivery of VFTs. Overall, the student questionnaires reflect the satisfaction of group with the teaching method and feedback was more positive for the virtual fieldtrips than the equivalent real-world trips in earlier years. Our findings also highlight several notable advantages associated with VFTs, including the ability to examine geology data at a range of scales, financial and access inclusivity, and reduced environmental impact. Several disadvantages with VFTs were also highlighted, including a reduction in social cohesion, and missing out on the experience of travelling and being outdoors. Our findings highlight implications for future application of VFTs and the opportunity to utilise both traditional fieldtrips and VFTs within a blended learning approach.

Sediment provenance analysis is important in reconstructing chronological and spatial relationships between source area erosion/exhumation and sediment deposition in adjacent basins. Here we provide new provenance data from conglomerate clast populations, sandstone petrography, heavy mineral assemblages and U–Pb detrital zircon geochronology from the 9 km-thick, Siluro-Devonian Lower Old Red Sandstone (LORS), northern Midland Valley Basin (MVB), Scotland. The MVB developed in the foreland to the Caledonian Orogeny and comprises a mixed succession of conglomerate and pebbly sandstone interbedded with volcanic lithologies. Analysis of 554 samples (137 petrographical thin sections across 22 formations/members; 390 conglomerate clast recordings across 7 locations; 17 heavy mineral and 10 detrital zircon samples) from the entire succession shows a proximal, consistent source or sources located to the east or NE. These results indicate that sediment derived directly from areas of Scandian uplift of Norwegian lithologies is unlikely to have made a significant contribution to the LORS of the northern MVB and the provenance instead lies more proximally in both the neighbouring Dalradian Supergroup metasedimentary rocks and other contemporaneous lithologies. The coarse-grained nature of the sedimentary rocks suggests consistent and continued uplift of these lithologies throughout deposition of the LORS. Integration of these provenance techniques allows robust interpretation of basin fill from a tectonically rejuvenating source in the Caledonian foreland. Supplementary material: MVB LORS palaeocurrent data; List of sample locations is available at https://doi.org/10.6084/m9.figshare.c.4661966

The Middle Jurassic Rattray Volcanic Province is located at the triple junction of the North Sea continental rift system. It has previously been thought to be sourced from three large central volcanoes: the Glenn, Fisher Bank and Ivanhoe volcanic centres. Re-interpretation using 3D seismic and well data shows that no volcanic centres are present and the Rattray Volcanics were instead sourced in fissure eruptions from linear vents, including the Buchan–Glenn Fissure System, a c. 25 km long zone of WSW–ENE-striking linear fissure vents and associated small volcanic edifices across the Buchan–Glenn Horst. The orientation of the fissures is broadly parallel to the Highland Boundary Fault, which intersects the Rattray Volcanics at the Buchan–Glenn Fissure System, implying that Mid-Jurassic magmatism exploited pre-existing crustal structural anisotropies established during the Caledonian Orogeny. The lack of large intrusive complexes beneath the Rattray Volcanics indicates that the pre-Middle Jurassic sedimentary sequences (e.g. the Devonian–Carboniferous Old Red Sandstone Group, the Permian Rotliegend and Zechstein groups and the Triassic Skagerrak Formation) extend further than previously supposed and therefore the presence of possible subvolcanic reservoir and source rock units within the triple junction of the Central North Sea may have been overlooked.

This Special Publication contains contributions for two meetings held to explore the links between geoscience and engineering in rivers and reservoirs (surface and subsurface). The first meeting was held in Brazil and, as a result, the volume contains many contributions from Brazil. The second was held in Edinburgh, and produced contributions from modern rivers in the USA, China, India and Scotland. The geological record from Carboniferous to Recent is represented. A range of outcrop techniques are presented along with statistical techniques used to identify patterns in the time series and spatial sense. The book is intended to cover the cross-disciplinary interest in rivers and their sediments, and will interest geologists, geomorphologists, civil, geotechnical and petroleum engineers, and government agencies. Some of the papers collected here demonstrate longer term impacts of human activity on rivers and how these might change the future geological record and, more importantly in the short term, impact on the UN Global Sustainability Goals.

We welcome the constructive comments of Manning et al. (2021) that our paper on the palaeogeographical evolution of the Rattray Volcanic Province provides a very valuable synthesis of this suite of rocks. Our paper presented a new evaluation of the stratigraphy and palaeogeographical setting of the Rattray Volcanic Province before, during and after the eruptions. The discussion underlines the fundamental science that can be undertaken and value attached to using subsurface data and cores obtained in the North Sea in general and the Rattray Volcanic Province in particular. The contribution of Manning et al. (2021) concerns the petrographic identification …

An analysis of the petrophysical and diagenetic effects of the emplacement of Cretaceous basaltic lava flows (Serra Geral Formation) on aeolian sandstones (Botucatu Formation) has been undertaken on core samples from the Parana Basin, Brazil. Between 0.1 and 1 m from the contact zone, acoustic wave velocities and porosities in sandstones show a significantly wider scatter than those located >1 m away from the lava contact. Higher P-wave values (average 3759.3 m s−1) occur between 0.1 and 1 m from the lava contact in contrast to those areas >1 m away (average 3376.8 m s−1), whilst the average porosity is 6.5% near the contact (0.1–1 m) and 10.7% away from the contact (>1 m). Petrographical evaluation reveals two diagenetic pathways responsible for modification of the petrophysical properties: early hydrothermal Mg-rich authigenesis (Type 1) and early chemical dissolution (Type 2). Type 3 diagenesis occurs away from the lava–sediment contact (>1 m), with the appearance of poikilitic calcite and smectite. The sandstone samples associated with Type 1 and Type 2 diagenesis display a decrease in porosity and increased acoustic velocities in relation to Type 3, while Type 3 samples show little or no variation in reservoir properties. The lava-induced diagenetic effects at the sandstone–lava contacts (0.1–1 m) may form a baffle or seal to fluids around the margins of the sandstone bodies. Therefore, whilst diagenesis associated with lava emplacement may hinder reservoir quality around the margins, the original reservoir properties are preserved within these large sandstone bodies. Supplementary material: Petrophysical and petrographical data are available at https://doi.org/10.6084/m9.figshare.c.5244473

The Nahr Menashe Unit (NMU), which forms the uppermost part of the Messinian succession, is one of the most cryptic and elusive sedimentary units present in the Levant basin (Eastern Mediterranean). We use a high-resolution 3D seismic dataset from offshore Lebanon to propose a new interpretation for its formation and evolution. The NMU varies laterally across the basin both in thickness and internal seismic characteristics. The variably coherent cyclic seismic packages affected by fracturing, faulting suggests that the NMU represent a reworked, layered evaporite succession interbedded with siliciclastics derived from both the Lebanon Highlands and the Latakia Ridge. Widespread semi-circular depressions, random linear imprints, passive surface collapsing and residual mound features within the NMU suggest that post depositional diagenetic and/or strong dissolution process often affected its evaporite-rich subunits. The well-known extended valley and tributary channel systems characterising the uppermost NMU shows mainly erosional rather than depositional features. Erosion started after deposition of NMU as a consequence of the maximum base level fall during the last phase of the Messinian Salinity Crisis (MSC). The channel and valley system were subsequently infilled by layered sediments here interpreted to represent post-MSC deep water marine reflooding. In conclusion, our analyses suggest the NMU can be interpreted as a mixed evaporite-siliciclastic system deposited in a shallow marine or marginal environment, which subsequently experienced fluvial erosion and later burial by transgressive/high-stand sediments.

The Little Minch Sill Complex consists of a series of stacked, multi-leaved Paleocene dolerite sills, which have primarily intruded into Mesozoic sedimentary rocks and Paleocene tuffs/?hyaloclastites within the Sea of Hebrides Basin. The Sea of Hebrides Basin is situated to the west of the Scottish mainland on the NE Atlantic margin. Two previously proposed models for the emplacement of the sill complex have opposing ideas for the location of magma input and the emplacement mechanisms. Both models have been constructed using data primarily from onshore outcrops on the Isle of Skye, Raasay and the Shiant Isles. However, these onshore outcrops only represent a quarter (1040 km2) of the entire extent of the sill complex, which is largely located offshore. To understand how the sill complex as a whole was emplaced within the basin, both onshore and offshore magma transport needs to be considered. Using high-resolution multibeam bathymetry data (up to 2 m resolution) obtained between 2008 and 2011, along with supporting seismic reflection, sparker and pinger data, a new assessment of the offshore extent and character of the sill complex has been constructed. Mapping of the large-scale relationships between intrusions and the host rock, along with morphological features such as magma lobes, magma fingers, transgressive wings, en echelon feeder dykes and the axis of saucer-/half-saucer-shaped intrusions, has indicated the magma flow directions within the intrusive network. Assessing the flow kinematics of the sills has provided insights into magma transport and emplacement processes offshore. Combining data from previously mapped onshore sills with data from our newly constructed model for magma emplacement offshore has allowed us to construct a new model for the emplacement of the Little Minch Sill Complex. This model demonstrates that major basin-bounding faults may have a lesser role in channelling magma through sedimentary basins than previously thought. Applying the knowledge obtained from this study could further progress our understanding of the effect of sill emplacement on fluid flow within volcanic rift basins worldwide, with direct impacts on the exploitation of petroleum and geothermal systems.

Reconstructing regional geological histories is challenging where basins have limited and/or fragmentary preservation. Several isolated outlier basins of Lower Old Red Sandstone (LORS) occur on the Scottish Grampian terrane; however, their sedimentology and relationship to other similar-aged LORS deposits has been poorly constrained, as has their significance in the wider Caledonian orogenic framework. Here we present a combination of new sedimentological and multidisciplinary provenance analyses for the LORS outliers at Aberdeen, Cabrach, New Aberdour, Rhynie and Tomintoul. Three facies associations are identified, the deposits of locally derived conglomeratic alluvial fans, which pass upward into fluvial channel and floodplain facies associations. Provenance data from conglomerate clast populations, sandstone petrography, heavy mineral assemblages, and U–Pb detrital zircon geochronology indicate derivation from the surrounding Dalradian Supergroup, with local influence from contemporaneous volcanic or plutonic lithologies. These data suggest a similar provenance to that of the northern Midland Valley Basin LORS, and a direct relationship between the LORS north and south of the Highland Boundary Fault. This indicates that the preserved outliers represent fragments of wider, unpreserved LORS cover that accumulated between the late phases of the Caledonian Orogeny and onset of post-orogenic collapse in the Mid-Devonian.

A number of geological and engineering parameters influence and control the performance and ultimate recovery from an oil reservoir. These are commonly interlinked and the relative importance of each can be difficult to unravel. These variables include geological parameters such as depositional environment, which has long been considered to be a key factor influencing the production characteristics of fields. However, quantifying the importance of any single factor, such as depositional environment, is complicated by the impact of the other variables (geological and engineering) and their numerous interdependencies. The main aim of this study is to unravel the impact of the depositional environment and primary facies architecture on reservoir performance using an empirical study of oilfields from the Norwegian Continental Shelf. A database of 91 fields, with a total of 7.8 Bbbl (billion barrels) of oil in place, has been built. Within this a total of 93 clastic reservoirs were classified into three gross depositional environments: continental, paralic/shallow marine and deep marine. The reservoirs were further classified into eight depositional environments in order to provide further granularity and to capture their depositional complexities. A further 28 parameters which capture other aspects that also impact production behaviour, such as reservoir depth, fluid type and structural complexity, were recorded for each reservoir. Principal component analysis (PCA) was utilized to explore the importance of sedimentological-dependent variables in the dataset, and to determine the parameters that have the strongest influence on the overall variability of the dataset. PCA revealed that parameters associated with field size and depth of burial had the most influence on recovery factor. Gross depositional environment and other stratigraphic-dependent parameters were the most significant geological factors. Fluid properties, such as API gravity and average gas/oil ratio, were unexpectedly among the less important parameters.

Historically, the continental Triassic successions of the Central North Sea have proven difficult to correlate, in part due to the poor palynomorph recovery associated with these sedimentary rocks. The existing framework for correlation is lithostratigraphic and, whilst this has proven effective in United Kingdom Continental Shelf (UKCS) Quad 30 where the mudstone members are well defined, elsewhere in the basin it is more problematic with confident identification of stratigraphic units becoming more difficult. Samples from 32 wells within UKCS Quads 22, 29 and 30, and Norwegian Quads 7, 15 and 16 underwent palynological analysis in which a processing method was utilized that was designed to concentrate palynomorph recovery from Triassic strata. The results of this analysis allowed the proposal of a new zonal scheme consisting of eight biozones. These biozones can then be used to correlate the Triassic successions of the Central North Sea (CNS), helping to provide both clarity and age constraint on previously disputed stratigraphic units, particularly the J-members of the Skagerrak Formation. Within the correlation framework outlined here, the Julius Mudstone Member is shown to be a productive horizon for palynomorph recovery, representing a widespread swamp environment. Here, its lateral extent is defined which is an important consideration when correlating the Triassic stratigraphy of the CNS given that this member can compartmentalize potential reservoirs contained within these successions. The stratigraphic palynology outlined here also allows clarity on the J-member equivalence of some of the informal units previously described within Triassic successions of the CNS, including the Marnock Shale and Heron Shale.

Acknowledgements The authors gratefully acknowledge support from Shell Brasil through the ‘BG05: UoA‐UFRGS‐SWB Sedimentary Basins’ project at UFRGS and the strategic importance given by ANP through the R&D levy regulation. The authors would like to thank Renan Guilherme de Souza and Adriano Reis for help in Tacuarembo/Uy Field Trip. This work is part of the current dual‐degree PhD from Gabriel Bertolini at Universidade Federal do Rio Grande do Sul and University of Aberdeen. We thank the editors, and Dr Eduardo Garzanti, Dr Luca Caracciolo and Dr Sebastian Oriolo for their kind and constructive reviews. We thank to Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) by the financial support (Grant: 203786/2017‐3).

The Salt Wash distributive fluvial system (DFS) of the Upper Jurassic Morrison Formation consists of stacked fluvial channel bodies interbedded with overbank deposits. The Salt Wash DFS has previously been recognised as a braided fluvial fan covering an area of over 100,000 km2. However, the addition of high‐resolution satellite imagery means planform exposures are now recognisable and point bar deposits can be identified in the sand‐rich proximal to medial reaches of the system, requiring a reassessment in this area of the DFS. An individual exhumed point bar deposit has been identified within a 30,000 km2 plan view area of meander belt in central Utah, which offers a unique perspective into the preserved internal distribution of facies and architecture. Field techniques have been utilised in conjunction with LiDAR and heli‐drone three‐dimensional outcrop datasets to compare measurements of the bedform and barform architectural elements within two contrasting outcrop exposure styles. One outcrop (Caineville Wash) has extensive plan view and vertical exposures, whereas the other (Caineville Road) is semi‐restricted to 2D canyon exposures with limited planform exposure. The contrasting exposure styles have been used to develop criteria for the interpretation of sandy meandering river deposits in 2D exposures, where plan view characteristics are not available. Internally, the point bar body exposed at Caineville Wash outcrop can be subdivided into three portions from the plan view imagery: upstream, central and downstream portions of a point bar. Mapping of the internal architecture of the fluvial bar allows recognition of downstream and laterally accreting components. The upstream and downstream portions of the point bar are predominately composed of downstream migrating barform deposits; and the central portion of the point bar consists of laterally accreting elements. Sedimentary logs taken from around the outcrop display vertical profiles commonly considered characteristic of a braided fluvial system. Through understanding the internal architecture of the Caineville Wash point bar deposit, it is possible to create a planform reconstruction of a stacked multi‐storey channel body from a two‐dimensional outcrop. Results indicate that point bar deposits in sand‐rich fluvial systems may have been incorrectly interpreted as braided deposits due to: 1) the presence of a significant proportion of downstream accreting elements within the point bar deposits; and 2) 2D sedimentary logs considered characteristic of a braided fluvial system (such as vertical grain‐size trends and repeating conglomerate lags). Subsequently, sandy meander‐belt deposits may be under‐represented within the proximal – medial portion of the Salt Wash DFS.

Amalgamated sandy meander belts and their deposits are common in modern continental and marine‐connected basins yet comprise a minor constituent of the reported fluvial rock record. This suggests that either amalgamated meander‐belts are uncommon in the rock record or that the recognition criteria are lacking to identify sandy meandering river deposits. To address this apparent discrepancy, the authors document the range and occurrence of amalgamated sandy meander belts (ASMB) from modern basins and the stratigraphic record. ASMB are widely distributed throughout both present and rock record sedimentary basins occurring in foreland, extensional, cratonic, strike‐slip and passive margin basins. They occur in all climatic settings ranging from tundra to hot deserts. Three specific occurrences of ASMB are recognised in modern basins: in the proximal to medial parts of distributive fluvial systems (DFS), as laterally‐confined belts that mainly form axial fluvial systems; and as valley‐confined meander belts that may infill bedrock, alluvial or coastal plain valleys. From the limited amount of rock record examples of ASMB that are available, it is clear that they occur in similar settings to those observed in modern basins, the recognition of which provides a framework for the further prediction and identification of ASMB in the rock record. The lack of recognition of ASMB in the rock record is considered to be due to an absence of characteristics that allow clear distinction between sandy meandering and braided fluvial deposits. Characteristics considered common to both include: multi‐storey, laterally extensive (sheet‐like) amalgamated channel belts, dominance of downstream accreting bedforms, no fining upwards grain‐size profile and little or no fine‐grained sediment and/or soil preservation. In contrast, features considered characteristic of meandering rivers such as inclined heterolithic stratification, high palaeocurrent dispersion, single storey channels and fining upwards grain‐size profiles are absent. The authors suggest that no single criterion can be used to definitively identify sandy meander belt deposits in the rock record and that a combination of systematic variations in accretion direction, palaeocurrent dispersal patterns and recognition of storey scale accretion surfaces is necessary to identify clearly this fluvial style. The common occurrence and distribution of sandy meander belts in modern sedimentary basins together with their limited recognition in the rock record suggests that their true stratigraphic distribution has yet to be determined. This has important implications for palaeogeographic reconstructions, understanding the impact of plant colonisation on fluvial planform style and predicting sandstone body dimensions and internal heterogeneity distribution within hydrocarbon reservoirs and aquifers.

This work was supported by Phase 2 of the Fluvial Systems Research Group (BP, BG, Chevron, ConocoPhillips and Total). AE thanks the University of Aberdeen for additional funding and MGMS thanks the Sao Paulo Research Foundation (FAPESP 2014/13937‐3). The authors also wish to thank numerous residents of the Bighorn Basin for their kind hospitality and access to land, and Isobel Buchanan and Alistair Swan for assistance in the field. The authors also thank reviewers Luca Colombera and Sian Davies‐Vollum and AE Christopher Fielding for helpful comments on this manuscript.

The NE Atlantic margin is one of the last frontier areas of hydrocarbon exploration within the UK Continental Shelf. In 2004, a major oil and gas discovery (Rosebank) was made within Paleocene–Eocene-age lavas in the Faroe–Shetland Basin. The Rosebank Field consists of intra-basaltic terrestrial to marginal-marine reservoir sequences, separated by basaltic lava flows and volcaniclastics. Despite the identification of a major intra-lava-incised drainage system running parallel to the SW–NE-trending Rosebank Field, the controls on the distribution of both the volcanics and the intra-basaltic sediments were previously unclear, in part due to the difficulties that volcanic sequences pose to seismic acquisition, processing and interpretation. This has led to uncertainty in defining the wider intra-basaltic play. However, the examination of the recently acquired FSB 2011–12 MultiClient GeoStreamer® Survey has facilitated an increased definition of the geological units within and below the volcanic succession, and a reinterpretation of the Late Paleocene–Early Eocene stratigraphy. Through integration of 3D seismic data and well analysis, we present a regional overview of the volcanics and intra-basaltic sediments in the Rosebank region of the Faroe–Shetland Basin. We find that the structural setting of the Rosebank Field, in addition to lava-flow morphology, strongly influences the distribution of the intra-basaltic play fairway within the Paleocene–Eocene-aged Flett Formation. Restriction of fluvial siliciclastic sediments adjacent to the Corona Ridge extends the theorized Rosebank play fairway to the area SW of the Rosebank Field. Our analysis indicates that understanding the underlying basin structure is integral to the success of intra-basaltic plays.

Sedimentary basins affected by hotspots often contain records of uplift and subsidence within coeval stratigraphic successions. The subsidence history can contain measurable perturbations in ancient palaeogeographies that can help constrain the duration of dynamic support. At c. 56 Ma the NE Atlantic experienced uplift related to the Iceland mantle plume. Within the Faroe–Shetland Basin, we document the stratigraphic record of subsidence following plume uplift, through integration of regional seismic datasets and well data. Subsidence following plume uplift is recorded by mapping the southward migration of palaeocoastlines throughout the early Eocene of the Faroe–Shetland Basin. We find that after initial uplift over 0.5 myr, subsidence was inhibited for 0.45 myr. Coeval with initiation of rifting in the North Atlantic, at 54.9 Ma, a c. 0.9 myr period of accelerated subsidence occurred, recorded by migration of the coastline by c. 80 km inland. We attribute these events to a prolonged period (2 myr) of dynamic support from the Iceland plume terminated by rapid loss of dynamic support coeval with rifting in the NE Atlantic at 54.9 Ma. Our results suggest that palaeogeographical analysis is a powerful tool in constraining the duration of dynamic support in basins affected by mantle plumes.

Aeolian science is faced with significant challenges that impact its ability to benefit from recent advances in information technology. The discipline deals with high-end systems in the form of ground and satellite based sensors, computer modeling and simulation, and wind tunnel experiments. Aeolian scientists also collect field data manually with observational methods that may differ significantly between studies with little agreement on even basic morphometric parameters and terminology. Data produced from these studies, while forming the core of research papers and reports, is rarely available to the community at large. Recent advances are also superimposed on an underlying semantic structure that dates to the 1800’s or earlier that is confusing, with ambiguously defined, and at times even contradictory, meanings. The aeolian “world-view” does not always fit within neat increments nor is defined by crisp objects. Instead change is continuous and features are fuzzy. Development of an ontological framework to guide spatiotemporal research is the fundamental starting point for organizing data in aeolian science. This requires a “rethinking” of how we define, collect, process, store and share data along with the development of a community-wide collaborative approach designed to bring the discipline into a data rich future. There is also a pressing need to develop efficient methods to integrate, analyze and manage spatial and temporal data and to promote data produced by aeolian scientists so it is available for preparing diagnostic studies, as input into a range of environmental models, and for advising national and international bodies that drive research agendas. This requires the establishment of working groups within the discipline to deal with content, format, processing pipelines, knowledge discovery tools and database access issues unique to aeolian science. Achieving this goal requires the development of comprehensive and highly-organized databases, tools that allow aeolian scientists as well as those in related disciplines to access and analyze the wealth of data available, and a supporting infrastructure and community-wide effort that allows aeolian scientists to communicate their results in replicable ways to scientists and decision and policy makers. Fortunately, much of the groundwork required to move aeolian science into a data rich future has been developed in other data rich physical science fields, and within the computer science and information technology disciplines.

Fluvial channel geometry classification schemes are commonly restricted in relation to the scale at which the study took place, often due to outcrop limitations or the need to conduct small-scale detailed studies. A number of classification schemes are present in the literature; however, there is often limited consistency between them, making application difficult. The aim of this study is to address this key problem by describing channel body geometries across a depositional basin to ensure that a wide range of architectures are documented. This was achieved by studying 28 locations over 4000 m of vertical succession in Palaeocene-aged and Early Eocene-aged deposits within the Bighorn Basin, Wyoming, USA. Five different channel body geometries have been defined based on the external geometric form, and internal arrangement and nature of storey contacts. These include the massive channel body geometry, semi-amalgamated channel body geometry, internally amalgamated channel body geometry and offset stacked channel body geometry, which are considered to be subdivisions of the sheet geometry of many other classifications. An isolated channel body geometry has also been recognized alongside splay channel and sheet sandstone geometries in the floodplain facies associations. Field evidence, including the stacking style of storey surfaces, suggests that the different geometries form a continuum. The nature and degree of amalgamation at the storey scale are important in producing the different geometries and are related to the degree of channel migration. It is speculated that this is the result of differences in sediment supply and available accommodation. In contrast to previous schemes, the classification scheme presented here recognizes the importance of transitional geometries. This geometrical range has been recognized because of the basin-scale nature of the study.

Nick Schofield, David Jolley, Simon Holford, Stuart Archer, Douglas Watson, Adrian Hartley, John Howell, David Muirhead, John Underhill and Paul Green

Understanding whether a system was unconfined, and deposited on a relatively unstructured basin-floor, or was confined by actively deforming substrate is important for the prediction of turbidite stratigraphy. Here we consider the Numidian turbidite system (Oligocene-Miocene) of Sicily - for many the type example of thick structureless submarine sandstones. New mapping and detailed sedimentology in the Nebrodi and Madonie Mountains (northern Sicily), allied to existing and new biostratigraphic data, challenge conventional interpretations for the Numidian system as a whole. Rather than having been deposited within an unstructured foredeep by relatively unconfined flows, we show that Numidian deposition was confined by active structures. These governed the routing of turbidity currents to create sand fairways and associated facies variations. The controlling structures include thrust-related folds together with inherited basin-floor faults. Existing models suggest that facies variations between adjacent outcrops on Sicily (and elsewhere) result from long-range stratigraphic variations being juxtaposed by later large-displacement thrusts. Our research reveals a much simpler tectonic structure but a more complex stratigraphic arrangement for the Numidian on Sicily - a characteristic of confined turbidite systems.

Made available in DSpace on 2019-10-06T15:37:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The influence of biotic processes in controlling the development of meandering channels in fluvial systems is controversial. The majority of the depositional history of the Earth's continents was devoid of significant biogeomorphic interactions, particularly those between vegetation and sedimentation processes. The prevailing perspective has been that prevegetation meandering channels rarely developed and that rivers with braided planforms dominated. However, recently acquired data demonstrate that meandering channel planforms are more widely preserved in prevegetation fluvial successions than previously thought. Understanding the role of prevailing fluvial dynamics in non- and poorly vegetated environments must rely on actualistic models derived from presently active rivers developed in sedimentary basins subject to desert-climate settings, the sparsest vegetated regions experiencing active sedimentation on Earth. These systems have fluvial depositional settings that most closely resemble those present in prevegetation (and extra-terrestrial) environments. Here, we present an analysis based on satellite imagery which reveals that rivers with meandering channel planforms are common in modern sedimentary basins in desert settings. Morphometric analysis of meandering fluvial channel behaviour, where vegetation is absent or highly restricted, shows that modern sparsely and non-vegetated meandering rivers occur across a range of slope gradients and basin settings, and possess a broad range of channel and meander-belt dimensions. The importance of meandering rivers in modern desert settings suggests that their abundance is likely underestimated in the prevegetation rock record, and models for recognition of their deposits need to be improved. CECS Universidade Federal do ABC (UFABC), Av. dos Estados 5001 Department of Geology and Petroleum Geology University of Aberdeen School of Earth and Environment University of Leeds School of Geographical and Earth Sciences University of Glasgow, University Avenue Institute of Energy and Environment USP, Av. Professor Luciano Gualberto 1289 Instituto de Geociências e Ciências Exatas UNESP, Avenida 24A 1515 Instituto de Geociências e Ciências Exatas UNESP, Avenida 24A 1515 FAPESP: 2014/13937-3

The Lower Cretaceous Botucatu Formation comprises a dry-aeolian system developed in western Gondwana and preserved within the Parana Basin of central South America. Multiproxy provenance analysis (detrital zircon U Pb dating, heavy mineral, petrographic and granulometric analysis) was undertaken along two 500 km transects of the northern Parana Basin (NW and NE transects). To assess the provenance variation within the aeolian stratigraphy, samples were taken from the base and top of the Botucatu Formation and from sandstones interbedded with volcanics in the overlying Serra Geral Formation. Granulometric analysis shows a mean fine- to very fine-grained sand. The bulk petrography yields an average composition of Q91F6L2, and heavy mineral analysis gives a mean of 86% of zircon-tourmaline-rutile, demonstrating the overall polycyclic nature of the sediment. The discrete occurrence of garnet, apatite and epidote indicates local sediment input points, providing indirect evidence for point-sourced fluvial input into an overall dry aeolian system. Detrital zircon U Pb LA-ICP-MS dating demonstrates a dominant Cambrian to Late Neoproterozoic (520–750 Ma) population with subsidiary Tonian-Stenian (0.9–1.2 Ga) and Orosirian-Rhyacian (1.9–2.3 Ga) contributions. The Botucatu Formation along the northern basin margin displays similar provenance to the southern part of the basin, pointing to a predominance of recycling processes within the basin. Statistical plots illustrate the detrital zircon age variability - recording an upward decrease in the age proportion of Permian and Tonian-Stenian populations and an increase in Cambrian-Late Neoproterozoic dates towards the top. Such variability can be related to the recycling of distinct Parana Basin strata. The proportion of Cambrian-Late Neoproterozoic dates increases in the NE, indicating a possible input from the Ribeira Belt granitoids. Similar to major-scale dune-fields, Botucatu erg register variable sand sources there are possibly linked with coexisting depositional systems. In summary, the northern Botucatu erg is mostly fed by local sources reworked from underlying Parana Basin units, with little direct input from basement sources and limited impact of regional wind-pattern variability.

The majority of sediment transport to the world9s oceans is routed via large deltas. We examine controls on delta apex location using a database of 84 of the world9s largest deltas. Of the dataset, 94% of apices are controlled by either bedrock valleys (80%) or Pleistocene alluvial valleys (14%), suggesting that the principal control on modern apex development is valley exit and/or bedslope-mediated avulsion and not hydrodynamic backwater length. Valley exit control on large delta apex location may have been as important in the rock record as it is today, and should be considered as a key control on delta development. Supplementary material : Tabulated data on backwater length and apex type for studied deltas available at https://doi.org/10.6084/m9.figshare.c.3469770

Understanding rift topography is essential for determining source areas, sediment pathways, and the type of sediment delivered to a rift basin; factors essential for interpreting petroleum systems in ancient rifts. Here we investigate Upper Jurassic sediments from the Josephine Ridge region of the Central Graben, North Sea, by integrating geophysical, palynological, petrophysical and sedimentological datasets to analyse the palaeoenvironments of the Jade and Judy horsts, the tops of which are not preserved. Interpretation of geophysical and petrophysical data together with core descriptions shows study wells to step progressively away from the Josephine Ridge into adjacent grabens. One hundred and five palynological samples from six wells range from the Oxfordian to the Lower Tithonian, spanning the syn-rift period of the Central Graben. Samples from the adjacent grabens and the Jade Horst are rich in dinoflagellate cysts and possess

Distinguishing axial and lateral sedimentary systems in rift basins is crucial for predicting reservoir distribution and quality, particularly where synrift strata are interrupted by mass transport complexes (MTCs). Upper Jurassic deep-marine synrift successions in the central North Sea have been studied to assess the temporal and spatial relationships of sediments and controls on reservoir quality. In the Late Jurassic, the central graben experienced erosion at rift margins, whereas adjacent grabens were starved and underfilled with marine sediments, supplied by axial and transverse systems. This study focused on sediments adjacent to a major intrabasinal high, the Josephine ridge. Data included seismic, wireline logs from 16 wells, and biostratigraphic and sedimentological analysis of 144 m (472 ft) of core. Synrift strata are dominated by mudstones but include MTCs interbedded with coarse sandstones at the rift margin and fine-grained turbidite sandstones in basinal depocenters. Petrographic and heavy mineral data indicate different provenance between MTCs and basinal turbidites. Turbidites correlate with periods of lowered relative sea level, during the initial rift phase, and record axial sediment supply. The composition of the MTCs corresponds to in situ strata on the adjacent Jade and Judy horsts. The distribution of MTCs implies formation by crestal collapse horsts during the rift climax and represents a transverse system, with no genetic relationship to axial turbidites. In starved deep-marine basins, fine-grained, well-sorted axial systems may provide the most extensive reservoirs. Transverse systems derived from isolated horsts are typically coarse-grained, poorly sorted, and spatially restricted, being unlikely to provide significant reservoir material.

The extension-driven break-up of the Pangean Supercontinent in the present-day Central and North Atlantic domains commenced during Permo-Triassic times. Permian rift processes in this region are generally attributed to crustal collapse during the latter part of the Hercynian/Variscan orogeny, but the Triassic rifting style is more complex and the presence of a single over-riding first-order control is equivocal. Basement terrane structures and boundaries provide pre-existing zones of weakness that had significant influences on the location, timing, orientation and extent of Triassic rifting. The 201 Ma Central Atlantic Magmatic Province (CAMP), a Large Igneous Province (LIP), increased lithospheric heat flow at the end of rifting, produced uplift and doming, and also contributed to deformation and subsequent continental breakup. Analysis of the Triassic basin structures in the Central Atlantic and North Atlantic domains (respectively Georgia to Nova Scotia and conjugate margin, and Newfoundland-Iberia) shows that four main basin types are geographically distributed: 1) southern basins (Georgia to Virginia), small to medium size with limited growth-structures, 2) basins in the Central-East domain (New Jersey-Nova Scotia), wide basins with growth-structures along long-lived inherited bounding faults, 3) basins in the Central-West domain (offshore NS and Morocco) that comprise numerous half-graben sub-basins in a lower unit and an upper very wide tabular unit, and 4) northern basins (Newfoundland-Portugal), that are tabular and extremely wide. Basin architectures suggest that subsidence was regional in extent and not necessarily controlled by main faults. Variations in crustal characteristics are considered to have led to the development of the four main basin types. Stratigraphic data show that the onset of deposition in the Central and southern North Atlantic domain was restricted to a Central Segment between two main structural lineaments. Overall, crustal rheology and inheritance exhibited first-order controls on subsidence and basin development. Triassic basins in the Central and North Atlantic domain were all filled by continental deposits in various palaeo-environments such as alluvial-fan, mega-fluvial systems, terminal fluvial systems, fan-delta fluvial systems, permanent oxic and anoxic lakes, playa lakes, and saline lakes, some of them interbedded with aeolian and volcanic deposits. Most basins were far from any marine domain but marine ingressions from the Tethys domain are inferred from dolomite and marine fauna in Portugal and from thick salt deposits in Morocco and offshore Canada during the late Rhaetian. A series of palaeogeographic maps are presented utilising plate reconstructions based on Sahabi et al (2004), in order to summarize continental-scale palaeo-environment distribution. Our tectono-stratigraphic model suggests that initial strain was accommodated in a Central Segment by inherited faults during the Early and Middle Triassic. During the Carnian, the rift domain was increasingly extended with the development of half-graben basins in the Central Segment and some in the Northern Segment. In both segments, the initial strain re-activated inherited faults and later the rift zones evolved towards significantly wider basins marked by the presence of a major erosional truncation surface across the basins and followed by lacustrine sedimentation that eventually overlapped paleo-topographic highs. Subsidence of such regional extent is likely driven by thermal processes following a phase of extreme lithospheric thinning and lower crustal removal associated with mantle uplift. The architecture of the Triassic rifting has the characteristics of the wide rift mode (very large basins with some active faults) for which subsidence is driven by lower crustal flow within a high heat-flow region. Nevertheless some faults were active during Late Triassic sedimentation but accounted for a relatively minor part of the overall subsidence. Pulses of active subsidence and topographic rejuvenation led to fluvial dominated deposition within basins. Non-rejuvenation of hinterland led to more lacustrine dominated sedimentation and eventual connection of basins across topographic highs due to regional (thermal) subsidence. During the latest Rhaetian, basins with the lowest elevations were possibly “flooded” by marine waters resulting in precipitation of thick salt deposits.

The authors would like to acknowledge Shell E and P for funding this study, Rob Raeside at the Acadia University and Liz Kosters for their support during the field seasons. We also would like to thank Brian P. J. Williams for enthusiastic discussions in the field.

We infer system-scale fluid flow in the Late Jurassic Salt Wash fluvial succession (SW USA) by plotting uranium deposit distribution against sedimentological data, using uranium distribution as a proxy for subsurface fluid flow. More than 90% of uranium deposits in the Salt Wash occur where sandstone forms 40–55% and sand-rich channel-belts form 20–50% of the succession, which coincides with changes in channel-belt connectivity and gross-scale architecture. The paucity of uranium below these cut-off values suggests that fluid flow is related directly to predictable downstream fining and facies variations in distributive fluvial systems. Supplementary material: A summary table of location data, key trends and the amalgamation ratio method is available at https://doi.org/10.6084/m9.figshare.c.2849581.

Detailed sedimentological examination of onshore sections through cyclic lacustrine deposits of the Middle Devonian succession of northern Scotland has been augmented with offshore data to allow the construction of a continuous 2.3 myr record of orbital forcing. These data provide an important record of climatic variance through the Devonian, which, by comparison with other records from this time, can significantly improve our understanding of the Devonian global climatic system. Precessional and eccentricity cycles are shown to be dominant by the direct measurement and extrapolation of depositional rates in well-exposed sections as well as the analysis of ratios between primary and modulating cycles. Spectral analysis has confirmed the presence of regular cycles throughout the offshore data, which provide a far longer record of orbitally forced cyclicity than previously available. The presence of a half precession cycle is also suggested. Similar up-section variations in cycle thicknesses are recorded from both the onshore and offshore succession. These variations and those in cycle symmetry are related to a trend from an underfilled to a balanced-fill basin state. Of further importance in controlling cycle thickness is the period of each cycle during which lacustrine conditions, and therefore lake level controlled accommodation, existed.

Since tectonic subsidence in sedimentary basins provides the potential for long-term facies preservation into the sedimentary record, analysis of geomorphic elements in modern continental sedimentary basins is required to understand facies relationships in sedimentary rocks. We use a database of over 700 modern sedimentary basins to characterize the fluvial geomorphology of sedimentary basins. Geomorphic elements were delineated in 10 representative sedimentary basins, focusing primarily on fluvial environments. Elements identified include distributive fluvial systems (DFS), tributive fluvial systems that occur between large DFS or in an axial position in the basin, lacustrine/playa, and eolian environments. The DFS elements include large DFS (> 30 km in length), small DFS ( Facies distributions in tributary positions and those on DFS appear to display specific morphologic patterns. Tributary rivers tend to increase in size in the downstream direction. Because axial tributary rivers are present in confined settings in the sedimentary basin, they migrate back and forth within a relatively narrow belt (relative to the overall size of the sedimentary basin). Thus, axial tributary rivers tend to display amalgamated channel belt form with minimal preservation potential of floodplain deposits. Chute and neck cutoff avulsions are also common on meandering rivers in these settings. Where rivers on DFS exit their confining valley on the basin margin, sediment transport capacity is reduced and sediment deposition occurs resulting in development of a ‘valley exit’ nodal avulsion point that defines the DFS apex. Rivers may incise downstream of the basin margin valley because of changes in sediment supply and discharge through climatic variability or tectonic processes. We demonstrate that rivers on DFS commonly decrease in width down-DFS caused by infiltration, bifurcation, and evaporation. In proximal areas, channel sands are amalgamated through repeated avulsion, reoccupation of previous channel belts, and limited accumulation space. When rivers flood on the medial to distal portions of a DFS, the floodwaters spread across a large area on the DFS surface and typically do not re-enter the main channel. In these distal areas, rivers on DFS commonly avulse, leaving a discrete sand body and providing high preservation potential for floodplain deposits. Additional work is needed to evaluate the geomorphic character of modern sedimentary basins in order to construct improved facies models for the continental sedimentary rock record. Specifically, models for avulsion, bifurcation, infiltration, and geomorphic form on DFS are required to better define and subsequently predict facies geometries. Studies of fluvial systems in sedimentary basins are also important for evaluating flood patterns and groundwater distributions for populations in these regions.

This work has been supported by the Fluvial Systems Research Group Consortium Phase 1, supported by BG, Chevron, Conoco Philips and Total. Discussions with John Howell on prograding sequences are greatly appreciated. The authors would also like to thank Anna Kulikova, Guy Prince, Kelsey McNamara and Karen Oud for assistance in the field. We thank reviewer Brian Willis, an anonymous reviewer and Editor Sebastien Castelltort for constructive comments that improved this manuscript.

Geomorphic archives, particularly longitudinal river profiles, are increasingly used as a proxy to reconstruct uplift rates in mountainous regions. Within the Atacama Desert, Northern Chile, slow, long-term erosion creates exceptional preservation of fluvial and alluvial surfaces. This enables river incision patterns to be used on a continental-scale (>250 km) along the western margin of the Andes (18°00'S to 20°15′S) and over a time frame from Miocene to Present day. The data show marked compartmentalisation of fluvial system behaviour with changes in incision rates from south to north creating 3 distinctly different regions. Within these different sectors, incision rates are broadly consistent between rivers suggesting a regional rather than a river specific control on rates. In Sector 1 (18°05′S to 19°20'S) the fluvial systems are exorheic with a terminal base level (the lowest base level to which the river system can erode) in the Pacific Ocean and span the Coastal Cordillera, Longitudinal Valley, Precordillera and western edge of the Western Cordillera. This constrains the total uplift over these regions to a minimum of 1200 m in 11 Myr with incision rates of ~200–120 m/Myr consistent with rapid but sustained uplift of the Andes in the Late Miocene. In Sector 2 (19°20'S to 19°50'S), to the immediate south, the rivers are shorter and terminate in the Longitudinal Valley, spanning only the Longitudinal Valley, Precordillera and the western edge of the Western Cordillera with lower incision rates of 100–50 m/Myr. Comparison of incision rates between Sector 1 and 2 can constrain the uplift of the Coastal Cordillera to 60 m/Myr which is in keeping with previous studies from the region. In southernmost Sector 3 (19°50'S to 20°10'S), the fluvial systems terminate in the Longitudinal Valley and span only the Longitudinal Valley and eastern part of the Precordillera with low incision rates of 50 to 25 m/Myr. Differences between Sectors 2 and 3 are attributable to drainage loss by tectonic beheading of catchments through uplift of the Cordillera de Domeyko fault system, placing a minimum constrain on uplift in this region of 50 to 25 m/Myr. This study demonstrates the applicability of large-scale fluvial archives to access not just the timing of uplift on a continental scale, but also the relative uplift of individual tectonic provinces.