Continental-dominated successions are often poorly constrained stratigraphically due to a lack of... more Continental-dominated successions are often poorly constrained stratigraphically due to a lack of robust biostratigraphic markers. This study provides the first dataset of δ 13 Corg together with magnetostratigraphic and biostratigraphic data from a thick continental-dominated succession at Lairière (northern Pyrenees, France). This section encompasses the latest Cretaceous up to the Paleocene-Eocene Thermal Maximum interval and is characterized by fluvial deposits, occasionally intercalated with continental carbonates, lacustrine deltaic deposits and shallow marine sediments. This work identifies δ 13 Corg events and assigns them to global δ 13 C geochemical events defined in Pyrenean and Tethyan marine successions, in which the stage boundaries are well calibrated. As the isotopic measurements are performed on dispersed organic matter in sedimentary rocks with a low organic content, we propose that analyses of the signal should take into consideration the depositional environment because variations in the organic matter content might affect the signal. We establish a high-resolution chronostratigraphy in terrestrial Paleocene deposits in the NE Pyrenean zone, recognize a late Selandian interval and define the Paleocene-Eocene Thermal Maximum event.
The Eocene-Miocene successions recovered at DSDP sites on the Jan Mayen Ridge (NE Atlantic) and o... more The Eocene-Miocene successions recovered at DSDP sites on the Jan Mayen Ridge (NE Atlantic) and on the adjacent East Greenland margin provide a sedimentary record of the rifting and separation of the Jan Mayen Microcontinent from East Greenland. A combination of palynology, conventional heavy mineral analysis, single-grain major and trace element geochemistry and radiometric dating of amphibole and zircon has revealed a major change in sediment provenance took place at the Early/Late Oligocene boundary corresponding to a prominent seismic reflector termed JA. During the Eocene and Early Oligocene, lateral variations in provenance character indicate multiple, small-scale transport systems. Site 349 and Kap Brewster were predominantly supplied from magmatic sources (Kap Brewster having a stronger subalkaline signature compared with Site 349), whereas Site 346 received almost exclusively metasedimentary detritus. By contrast, Late Oligocene provenance characteristics are closely compar...
The Faroe–Shetland Basin (FSB) is one of the only significant exploration frontiers remaining on ... more The Faroe–Shetland Basin (FSB) is one of the only significant exploration frontiers remaining on the UK Continental Shelf. Over half of the basin's discovered reserves and resources lie along two intra-basinal highs, the Corona Ridge and the Rona Ridge. In contrast to the Rona Ridge, the central-northern Corona Ridge has received much less attention. To reveal new insights into the geology, structural configuration and hydrocarbon prospectivity of the central-northern Corona Ridge, we analyse 3D seismic data and data from the exploration wells 213/23-1 (Eriboll), 214/21a-2 (South Uist) and 213/25c-1V (North Uist). This study extends the Colsay T40–T45 sub- and intra-basaltic play concept from the Rosebank Field NE along the Corona Ridge, at least into well 213/23-1. Analysis also suggests that no Triassic strata are present within well 213/23-1, challenging the previous understanding of Triassic distribution within the central FSB. Our findings show that the central-northern Cor...
The Yola Sub-basin represents the lower portion of the bifurcated Upper Benue Trough, whose origi... more The Yola Sub-basin represents the lower portion of the bifurcated Upper Benue Trough, whose origin has been linked to the opening of the Atlantic Ocean in the Mesozoic. The sub-basin fill consists predominantly of siliciclastic and carbonate deposits, the ages of which have remained controversial until now. This work employs field observations integrated with palynostratigraphy to refine the stratigraphy of these Upper Cretaceous deposits. We delineate five palynozones, spanning the upper Albian-Cenomanian, middle Cenomanian, upper Cenomanian, Turonian and Coniacian-Santonian. This palynology indicates that rocks previously thought to be Turonian are in fact Cenomanian. Further, the species Florentinia berran, Florentinia khaldunii, and Subtilisphaera senegalensis are all low latitude dinocysts that previously have only been reported from the Tethyan realm. Their presence here, together with the sedimentology, implies that there was an influx of Tethyan waters into the epeiric sea of the Benue Trough in the Cenomanian. The collective sedimentary and palynological evidence indicates that the Cenomanian transgression was well established in the Yola Subbasin, and more broadly in the Upper Benue Trough, connecting Tethys with the Gulf of Guinea.
A series of offshore intra-basinal igneous centres have been documented across the North Atlantic... more A series of offshore intra-basinal igneous centres have been documented across the North Atlantic Igneous Province including the UK, Ireland and Greenland. However, inconsistent cross-border terminology implies that similar features are not present in the Norwegian offshore, which, in turns, leads to misperceptions of cross-border geological differences. This paper presents evidence for a series of Norwegian igneous centres and suggests a consistent non-genetic cross-border terminology. In the Møre Basin, several igneous centres sit close to the continent–ocean boundary (COB), which have previously been identified as seamounts and/or ‘outer highs’. To provide cross-border consistency these features are consolidated under umbrella terms: igneous centres or volcanic fissures. Further centres are probably present within the Møre Basin (east of the COB) where 3D seismic data were not available. In the Vøring Basin two new igneous centres, one intrusive and one extrusive, are identified ...
Historically, the continental Triassic successions of the Central North Sea have proven difficult... more 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 ag...
The Northern Kenya Rift is an important natural laboratory for understanding continental rifting ... more The Northern Kenya Rift is an important natural laboratory for understanding continental rifting processes. However, much of the current understanding of its geological evolution is based on surface outcrops within footwall highs due to a lack of subsurface geological constraints. In this paper, we present an investigation of the Cenozoic stratigraphy and volcano-tectonic relationship of the volcanic sequences within the Turkana Depression (namely the North Lokichar, North Kerio and Turkana Basins). We integrate regional seismic reflection data collected as part of ongoing petroleum exploration in the area with lithological and biostratigraphic data from new wells that were drilled in 2014 and 2015 (Epir-1 and Emesek-1). This has allowed linking and extrapolation of the detailed stratigraphy of the paleontologically important Lothagam site to the volcanic sequences within the Napedet Hills, North Lokichar, North Kerio and Turkana Basins. The site of the Plio-Pleistocene-age Turkana ...
The Rollrock Section in the Sverdrup Basin, Arctic Canada, is one of the northernmost outcrops wh... more The Rollrock Section in the Sverdrup Basin, Arctic Canada, is one of the northernmost outcrops where the Jurassic-Cretaceous transition is accessible. The over 500 m thick sedimentary succession exposes the Oxfordian to Valanginian Ringnes and Deer Bay formations. Macrofauna from 15 discrete horizons includes ammonites, Buchia bivalves and belemnites. These fossils improve the biostratigraphy of the Tithonian and Berriasian in the Sverdrup Basin, provide correlation to the remainder of the Boreal Realm and set reliable calibration points. The occurrence of Buchia rugosa in the Ringnes Formation moves the upper formation boundary of from the top of the Kimmeridgian into the lower Tithonian. Dorsoplanites maximus and D. sachsi document the middle Tithonian Dorsoplanites maximus Zone in Arctic Canada for the first time. The late Tithonian to early Berriasian Buchia terebratuloides is considered to be the best approximate indicator of the Jurassic-Cretaceous transition in the Rollrock Section. The middle early Berriasian Praetollia maynci and the late early Berriasian Borealites fedorovi tie the respective horizons to the successive Chetaites sibiricus and Hectoroceras kochi zones. Two species of the belemnite Arctoteuthis, collected from an interval with glendonites, suggest a Valanginian age for the upper Deer Bay Formation. The dearth of Late Jurassic to earliest Cretaceous macrofossils in the Sverdrup Basin is inferred to be predominantly a function of diagenetic carbonate loss. Abundant dropstones and glendonites in the middle Tithonian to middle Valanginian interval suggest cold climatic conditions, and make the Rollrock Section a prime candidate for studying the Arctic environmental perturbations of this time.
Geological Society, London, Special Publications, 2019
Onshore exposures of the North Atlantic Igneous Province have been studied in detail for over 200... more Onshore exposures of the North Atlantic Igneous Province have been studied in detail for over 200 years, whereas the more extensive offshore volcanic stratigraphy is significantly less well constrained with the exception of a small number of boreholes. Within this study we integrate seismic and well data across the northern Faroe–Shetland Basin and Møre Marginal High to improve understanding of the volcanic stratigraphy and its relationship to rifting in the NE Atlantic. Volcanic seismic facies, including compound and tabular lavas and hyaloclastites (representing subaerial and subaqueous emplacement), are interpreted across the study area, calibrated by the Lagavulin borehole. The volcanic sequence was erupted betweenc.56.1 and 55.2 Ma, when subaerial conditions dominated in the region, but extensive lava deltas developed in a seaway east of the main lava field. Geochemical and thickness variations within the volcanic pile have important implications for the regional rifting histor...
Geological Society, London, Special Publications, 2019
The NE Atlantic volcanic rifted margins include vast underexplored basin areas neighbouring matur... more The NE Atlantic volcanic rifted margins include vast underexplored basin areas neighbouring mature petroleum-producing regions. We appraise the cross-border prospectivity of the outer and central Faroe–Shetland, Møre and southern Vøring basins and present insights from extensive new 3D seismic surveys. Regional seismic surfaces are used to compile a cross-border seismic profile highlighting key discoveries from the UK Rosebank field in the SW to the Norwegian Ormen Lange field in the NE. Cretaceous to Paleocene reservoirs remain the main exploration focus seaward of the platform areas, and the presence of several large untested structures presents important exploration targets in the mid-Norway region. Improved imaging of the areas affected by Paleogene igneous rocks reveals major untested sub-basalt structures including some regions on the marginal highs where the basalt cover has been entirely removed by erosion, revealing sub-basalt stratigraphy and structures with pre-Cretaceous...
The magma-rich North Atlantic Margin is one of the last frontier areas of hydrocarbon exploration... more The magma-rich North Atlantic Margin is one of the last frontier areas of hydrocarbon exploration within the United Kingdom Continental Shelf. In 2004, a major oil and gas discovery (Rosebank) was made within Palaeocene to 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 intravolcanic sediments was 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 FSB2011/12 MultiClient GeoStreamer® Survey has facilitated increased definition of the geological units within and below the volcanic succession, and a reinterpretation of the Late Palaeocene to 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 Palaeocene-Eocene Flett Formation. Restriction of fluvial siliciclastic sediments adjacent to the Corona Ridge extends the theorised Rosebank play fairway to the area southwest of the Rosebank Field. Our analysis indicates that understanding basin structure is integral to the success of intra-basaltic plays. Hydrocarbon exploration in the Faroe-Shetland Basin (FSB), located on the Atlantic Margin of the United Kingdom Continental Shelf (UKCS), has been ongoing for the last 40 years.
The UK Rockall Basin is one of the most underexplored areas of the UK Continental Shelf (UKCS), w... more The UK Rockall Basin is one of the most underexplored areas of the UK Continental Shelf (UKCS), with only 12 exploration wells drilled since 1980. With only one discovery made in 2000 (Benbecula (154/1-1) gas discovery), the general view of the basin from an exploration viewpoint is not positive. However, over the last 15 years, our knowledge of the petroleum systems of the Atlantic Margin has substantially increased. With the recent acquisition of new seismic data by the UK Government as part of the OGA's Frontiers Basin Research Programme, it is a pertinent time to re-examine the prospectivity of the UK Rockall Basin.This paper presents a history of exploration within the UK Rockall Basin, from the first well drilled in the basin in 1980, to the last well, drilled in 2006. We then present new insights into the lack of success during exploration within the basin, in particular by focusing on the extensive Early Cenozoic volcanic rocks within Rockall, to illustrate the wide rang...
Fault block basins exposed along NE Greenland provide insights into the tectonic evolution of Eas... more Fault block basins exposed along NE Greenland provide insights into the tectonic evolution of East Greenland and the Norwegian-Greenland Sea. We present a new geological map and cross sections of the Traill Ø region, NE Greenland, which formed the western margin of the Vøring Basin prior to Ceno zoic seafloor spreading. Observations support a polyphase rift evolution with three rift phases during Devonian-Triassic, Jurassic-Cretaceous, and Cenozoic time. The greatest amounts of faulting and block rotation occurred during Cenozoic rifting, which we correlate with development of the continent-ocean transition after ca. 56 Ma and the Jan Mayen microcontinent after ca. 36 Ma. A newly devised macrofaunal-based stratigraphic framework for the Cretaceous sandy mudstone succession provides insights into Jurassic-Cretaceous rifting. We identify a reduction in sedimentation rates during the Late Cretaceous; this corresponds to a transition from structurally confined to unconfined sedimentation that coincides with increased clastic sedimentation to the Vøring and Møre Basins derived from East Greenland. With each rift phase we record an increase in the number of active faults and a decrease in the spacing between them. We attribute this to fault block rotation that leads to an excess build-up of stress that can only be released by the creation of new steep faults. In addition, we observe a stepwise migration of deformation toward the rift axis that we attribute to preexisting lithospheric heterogeneity that was modified during subsequent rift and post-rift phases. Such observations are not readily conformable to classic rift evolution models and highlight the importance of post-rift lithospheric processes that occur during polyphase rift evolution.
A study of the palynomorphs of the Upper Jurassic Helmsdale Boulder Beds Formation, of the Inner ... more A study of the palynomorphs of the Upper Jurassic Helmsdale Boulder Beds Formation, of the Inner Moray Firth Basin has been conducted to determine if cooling of the marine environment was experienced on the Scottish landmass. Thirty samples contain assemblages dominated by trilete spores and alete pollen grains. The composition of the palynofloras was analysed by reference to their botanical affinity and using correspondence and C-means Fuzzy Cluster statistical analysis for their ecological setting. Assemblages are observed to vary through the Upper Jurassic; those in the Kimmeridgian being dominated by spores from ferns and fern allies, whilst the Tithonian deposits show a progressive change to pollen dominated by coniferous gymnosperms. Analysis of the miospores has revealed a distinct bi-modal distribution, interpreted to represent a climatic shift from a warm humid-temperate in the Kimmeridgian to a cool semi-arid climate, in the wheatleyensis Zone of the Upper Tithonian, correlating well with IMF sea-temperature change and climate change previously identified at lower latitudes. This climate change is associated with a phase of cooling at the Jurassic-Cretaceous boundary.
Volcanism associated with Large Igneous Provinces (LIPs) has been implicated in both global clima... more Volcanism associated with Large Igneous Provinces (LIPs) has been implicated in both global climate and environmental change. To determine the plant ecological impact of LIP volcanism we have examined plant community succession in sedimentary interbeds of the Columbia River Flood Basalt Province (CRBP). Inter-basaltic vegetation is characterised by primary succession communities that inhabit fresh lava surfaces until terminated by the next eruptive event, and it is assumed that longer volcanic hiatuses should lead to more mature plant communities. This expected succession trajectory is contradicted by palynological data which show that seral succession declines during the phase of waning CRPB volcanism and prolonged interbed intervals. Frequent volcanic activity and increased deposition of Snake River Plain hot spot ashes during this phase resulted in ecological disturbance of intra-lava field vegetation. This suggests that the CRBP flora was driven largely by extrinsic forcing, and implies that LIP volcanism of similar scale and magnitude to that of the CRBP had less environmental impact than understood as yet. This study supports the theory that past biotic extinctions were triggered by numerous factors rather than a single geological event.
Earth and Environmental Science Transactions of the Royal Society of Edinburgh
The Paleogene lava flows of the Faroe Islands Basalt Group are divided into three relatively thic... more The Paleogene lava flows of the Faroe Islands Basalt Group are divided into three relatively thick formations. The oldest, the Beinisvørð Formation is separated from the second lava flow succession, the Malinstindur Formation, by two formations composed primarily of volcaniclastic rocks. The oldest of these, the Prestfjall Formation has been interpreted as a period of eruptive quiescence and linked to changes in mantle melting. It is characterised in the south by the occurrence of coals, while the overlying Hvannhagi Formation is a sequence of primary and remobilised volcaniclastic strata. Field, laboratory, palynology, and photogrammetry studies have been used to investigate variations in facies and architecture within these volcaniclastic formations. The data reveal significantly different depositional systems in the Prestfjall and Hvannhagi formations over the ~40 km from the island of Vágar in the north to the island of Suðuroy in the south. Facies distribution in both the Prest...
Continental-dominated successions are often poorly constrained stratigraphically due to a lack of... more Continental-dominated successions are often poorly constrained stratigraphically due to a lack of robust biostratigraphic markers. This study provides the first dataset of δ 13 Corg together with magnetostratigraphic and biostratigraphic data from a thick continental-dominated succession at Lairière (northern Pyrenees, France). This section encompasses the latest Cretaceous up to the Paleocene-Eocene Thermal Maximum interval and is characterized by fluvial deposits, occasionally intercalated with continental carbonates, lacustrine deltaic deposits and shallow marine sediments. This work identifies δ 13 Corg events and assigns them to global δ 13 C geochemical events defined in Pyrenean and Tethyan marine successions, in which the stage boundaries are well calibrated. As the isotopic measurements are performed on dispersed organic matter in sedimentary rocks with a low organic content, we propose that analyses of the signal should take into consideration the depositional environment because variations in the organic matter content might affect the signal. We establish a high-resolution chronostratigraphy in terrestrial Paleocene deposits in the NE Pyrenean zone, recognize a late Selandian interval and define the Paleocene-Eocene Thermal Maximum event.
The Eocene-Miocene successions recovered at DSDP sites on the Jan Mayen Ridge (NE Atlantic) and o... more The Eocene-Miocene successions recovered at DSDP sites on the Jan Mayen Ridge (NE Atlantic) and on the adjacent East Greenland margin provide a sedimentary record of the rifting and separation of the Jan Mayen Microcontinent from East Greenland. A combination of palynology, conventional heavy mineral analysis, single-grain major and trace element geochemistry and radiometric dating of amphibole and zircon has revealed a major change in sediment provenance took place at the Early/Late Oligocene boundary corresponding to a prominent seismic reflector termed JA. During the Eocene and Early Oligocene, lateral variations in provenance character indicate multiple, small-scale transport systems. Site 349 and Kap Brewster were predominantly supplied from magmatic sources (Kap Brewster having a stronger subalkaline signature compared with Site 349), whereas Site 346 received almost exclusively metasedimentary detritus. By contrast, Late Oligocene provenance characteristics are closely compar...
The Faroe–Shetland Basin (FSB) is one of the only significant exploration frontiers remaining on ... more The Faroe–Shetland Basin (FSB) is one of the only significant exploration frontiers remaining on the UK Continental Shelf. Over half of the basin's discovered reserves and resources lie along two intra-basinal highs, the Corona Ridge and the Rona Ridge. In contrast to the Rona Ridge, the central-northern Corona Ridge has received much less attention. To reveal new insights into the geology, structural configuration and hydrocarbon prospectivity of the central-northern Corona Ridge, we analyse 3D seismic data and data from the exploration wells 213/23-1 (Eriboll), 214/21a-2 (South Uist) and 213/25c-1V (North Uist). This study extends the Colsay T40–T45 sub- and intra-basaltic play concept from the Rosebank Field NE along the Corona Ridge, at least into well 213/23-1. Analysis also suggests that no Triassic strata are present within well 213/23-1, challenging the previous understanding of Triassic distribution within the central FSB. Our findings show that the central-northern Cor...
The Yola Sub-basin represents the lower portion of the bifurcated Upper Benue Trough, whose origi... more The Yola Sub-basin represents the lower portion of the bifurcated Upper Benue Trough, whose origin has been linked to the opening of the Atlantic Ocean in the Mesozoic. The sub-basin fill consists predominantly of siliciclastic and carbonate deposits, the ages of which have remained controversial until now. This work employs field observations integrated with palynostratigraphy to refine the stratigraphy of these Upper Cretaceous deposits. We delineate five palynozones, spanning the upper Albian-Cenomanian, middle Cenomanian, upper Cenomanian, Turonian and Coniacian-Santonian. This palynology indicates that rocks previously thought to be Turonian are in fact Cenomanian. Further, the species Florentinia berran, Florentinia khaldunii, and Subtilisphaera senegalensis are all low latitude dinocysts that previously have only been reported from the Tethyan realm. Their presence here, together with the sedimentology, implies that there was an influx of Tethyan waters into the epeiric sea of the Benue Trough in the Cenomanian. The collective sedimentary and palynological evidence indicates that the Cenomanian transgression was well established in the Yola Subbasin, and more broadly in the Upper Benue Trough, connecting Tethys with the Gulf of Guinea.
A series of offshore intra-basinal igneous centres have been documented across the North Atlantic... more A series of offshore intra-basinal igneous centres have been documented across the North Atlantic Igneous Province including the UK, Ireland and Greenland. However, inconsistent cross-border terminology implies that similar features are not present in the Norwegian offshore, which, in turns, leads to misperceptions of cross-border geological differences. This paper presents evidence for a series of Norwegian igneous centres and suggests a consistent non-genetic cross-border terminology. In the Møre Basin, several igneous centres sit close to the continent–ocean boundary (COB), which have previously been identified as seamounts and/or ‘outer highs’. To provide cross-border consistency these features are consolidated under umbrella terms: igneous centres or volcanic fissures. Further centres are probably present within the Møre Basin (east of the COB) where 3D seismic data were not available. In the Vøring Basin two new igneous centres, one intrusive and one extrusive, are identified ...
Historically, the continental Triassic successions of the Central North Sea have proven difficult... more 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 ag...
The Northern Kenya Rift is an important natural laboratory for understanding continental rifting ... more The Northern Kenya Rift is an important natural laboratory for understanding continental rifting processes. However, much of the current understanding of its geological evolution is based on surface outcrops within footwall highs due to a lack of subsurface geological constraints. In this paper, we present an investigation of the Cenozoic stratigraphy and volcano-tectonic relationship of the volcanic sequences within the Turkana Depression (namely the North Lokichar, North Kerio and Turkana Basins). We integrate regional seismic reflection data collected as part of ongoing petroleum exploration in the area with lithological and biostratigraphic data from new wells that were drilled in 2014 and 2015 (Epir-1 and Emesek-1). This has allowed linking and extrapolation of the detailed stratigraphy of the paleontologically important Lothagam site to the volcanic sequences within the Napedet Hills, North Lokichar, North Kerio and Turkana Basins. The site of the Plio-Pleistocene-age Turkana ...
The Rollrock Section in the Sverdrup Basin, Arctic Canada, is one of the northernmost outcrops wh... more The Rollrock Section in the Sverdrup Basin, Arctic Canada, is one of the northernmost outcrops where the Jurassic-Cretaceous transition is accessible. The over 500 m thick sedimentary succession exposes the Oxfordian to Valanginian Ringnes and Deer Bay formations. Macrofauna from 15 discrete horizons includes ammonites, Buchia bivalves and belemnites. These fossils improve the biostratigraphy of the Tithonian and Berriasian in the Sverdrup Basin, provide correlation to the remainder of the Boreal Realm and set reliable calibration points. The occurrence of Buchia rugosa in the Ringnes Formation moves the upper formation boundary of from the top of the Kimmeridgian into the lower Tithonian. Dorsoplanites maximus and D. sachsi document the middle Tithonian Dorsoplanites maximus Zone in Arctic Canada for the first time. The late Tithonian to early Berriasian Buchia terebratuloides is considered to be the best approximate indicator of the Jurassic-Cretaceous transition in the Rollrock Section. The middle early Berriasian Praetollia maynci and the late early Berriasian Borealites fedorovi tie the respective horizons to the successive Chetaites sibiricus and Hectoroceras kochi zones. Two species of the belemnite Arctoteuthis, collected from an interval with glendonites, suggest a Valanginian age for the upper Deer Bay Formation. The dearth of Late Jurassic to earliest Cretaceous macrofossils in the Sverdrup Basin is inferred to be predominantly a function of diagenetic carbonate loss. Abundant dropstones and glendonites in the middle Tithonian to middle Valanginian interval suggest cold climatic conditions, and make the Rollrock Section a prime candidate for studying the Arctic environmental perturbations of this time.
Geological Society, London, Special Publications, 2019
Onshore exposures of the North Atlantic Igneous Province have been studied in detail for over 200... more Onshore exposures of the North Atlantic Igneous Province have been studied in detail for over 200 years, whereas the more extensive offshore volcanic stratigraphy is significantly less well constrained with the exception of a small number of boreholes. Within this study we integrate seismic and well data across the northern Faroe–Shetland Basin and Møre Marginal High to improve understanding of the volcanic stratigraphy and its relationship to rifting in the NE Atlantic. Volcanic seismic facies, including compound and tabular lavas and hyaloclastites (representing subaerial and subaqueous emplacement), are interpreted across the study area, calibrated by the Lagavulin borehole. The volcanic sequence was erupted betweenc.56.1 and 55.2 Ma, when subaerial conditions dominated in the region, but extensive lava deltas developed in a seaway east of the main lava field. Geochemical and thickness variations within the volcanic pile have important implications for the regional rifting histor...
Geological Society, London, Special Publications, 2019
The NE Atlantic volcanic rifted margins include vast underexplored basin areas neighbouring matur... more The NE Atlantic volcanic rifted margins include vast underexplored basin areas neighbouring mature petroleum-producing regions. We appraise the cross-border prospectivity of the outer and central Faroe–Shetland, Møre and southern Vøring basins and present insights from extensive new 3D seismic surveys. Regional seismic surfaces are used to compile a cross-border seismic profile highlighting key discoveries from the UK Rosebank field in the SW to the Norwegian Ormen Lange field in the NE. Cretaceous to Paleocene reservoirs remain the main exploration focus seaward of the platform areas, and the presence of several large untested structures presents important exploration targets in the mid-Norway region. Improved imaging of the areas affected by Paleogene igneous rocks reveals major untested sub-basalt structures including some regions on the marginal highs where the basalt cover has been entirely removed by erosion, revealing sub-basalt stratigraphy and structures with pre-Cretaceous...
The magma-rich North Atlantic Margin is one of the last frontier areas of hydrocarbon exploration... more The magma-rich North Atlantic Margin is one of the last frontier areas of hydrocarbon exploration within the United Kingdom Continental Shelf. In 2004, a major oil and gas discovery (Rosebank) was made within Palaeocene to 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 intravolcanic sediments was 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 FSB2011/12 MultiClient GeoStreamer® Survey has facilitated increased definition of the geological units within and below the volcanic succession, and a reinterpretation of the Late Palaeocene to 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 Palaeocene-Eocene Flett Formation. Restriction of fluvial siliciclastic sediments adjacent to the Corona Ridge extends the theorised Rosebank play fairway to the area southwest of the Rosebank Field. Our analysis indicates that understanding basin structure is integral to the success of intra-basaltic plays. Hydrocarbon exploration in the Faroe-Shetland Basin (FSB), located on the Atlantic Margin of the United Kingdom Continental Shelf (UKCS), has been ongoing for the last 40 years.
The UK Rockall Basin is one of the most underexplored areas of the UK Continental Shelf (UKCS), w... more The UK Rockall Basin is one of the most underexplored areas of the UK Continental Shelf (UKCS), with only 12 exploration wells drilled since 1980. With only one discovery made in 2000 (Benbecula (154/1-1) gas discovery), the general view of the basin from an exploration viewpoint is not positive. However, over the last 15 years, our knowledge of the petroleum systems of the Atlantic Margin has substantially increased. With the recent acquisition of new seismic data by the UK Government as part of the OGA's Frontiers Basin Research Programme, it is a pertinent time to re-examine the prospectivity of the UK Rockall Basin.This paper presents a history of exploration within the UK Rockall Basin, from the first well drilled in the basin in 1980, to the last well, drilled in 2006. We then present new insights into the lack of success during exploration within the basin, in particular by focusing on the extensive Early Cenozoic volcanic rocks within Rockall, to illustrate the wide rang...
Fault block basins exposed along NE Greenland provide insights into the tectonic evolution of Eas... more Fault block basins exposed along NE Greenland provide insights into the tectonic evolution of East Greenland and the Norwegian-Greenland Sea. We present a new geological map and cross sections of the Traill Ø region, NE Greenland, which formed the western margin of the Vøring Basin prior to Ceno zoic seafloor spreading. Observations support a polyphase rift evolution with three rift phases during Devonian-Triassic, Jurassic-Cretaceous, and Cenozoic time. The greatest amounts of faulting and block rotation occurred during Cenozoic rifting, which we correlate with development of the continent-ocean transition after ca. 56 Ma and the Jan Mayen microcontinent after ca. 36 Ma. A newly devised macrofaunal-based stratigraphic framework for the Cretaceous sandy mudstone succession provides insights into Jurassic-Cretaceous rifting. We identify a reduction in sedimentation rates during the Late Cretaceous; this corresponds to a transition from structurally confined to unconfined sedimentation that coincides with increased clastic sedimentation to the Vøring and Møre Basins derived from East Greenland. With each rift phase we record an increase in the number of active faults and a decrease in the spacing between them. We attribute this to fault block rotation that leads to an excess build-up of stress that can only be released by the creation of new steep faults. In addition, we observe a stepwise migration of deformation toward the rift axis that we attribute to preexisting lithospheric heterogeneity that was modified during subsequent rift and post-rift phases. Such observations are not readily conformable to classic rift evolution models and highlight the importance of post-rift lithospheric processes that occur during polyphase rift evolution.
A study of the palynomorphs of the Upper Jurassic Helmsdale Boulder Beds Formation, of the Inner ... more A study of the palynomorphs of the Upper Jurassic Helmsdale Boulder Beds Formation, of the Inner Moray Firth Basin has been conducted to determine if cooling of the marine environment was experienced on the Scottish landmass. Thirty samples contain assemblages dominated by trilete spores and alete pollen grains. The composition of the palynofloras was analysed by reference to their botanical affinity and using correspondence and C-means Fuzzy Cluster statistical analysis for their ecological setting. Assemblages are observed to vary through the Upper Jurassic; those in the Kimmeridgian being dominated by spores from ferns and fern allies, whilst the Tithonian deposits show a progressive change to pollen dominated by coniferous gymnosperms. Analysis of the miospores has revealed a distinct bi-modal distribution, interpreted to represent a climatic shift from a warm humid-temperate in the Kimmeridgian to a cool semi-arid climate, in the wheatleyensis Zone of the Upper Tithonian, correlating well with IMF sea-temperature change and climate change previously identified at lower latitudes. This climate change is associated with a phase of cooling at the Jurassic-Cretaceous boundary.
Volcanism associated with Large Igneous Provinces (LIPs) has been implicated in both global clima... more Volcanism associated with Large Igneous Provinces (LIPs) has been implicated in both global climate and environmental change. To determine the plant ecological impact of LIP volcanism we have examined plant community succession in sedimentary interbeds of the Columbia River Flood Basalt Province (CRBP). Inter-basaltic vegetation is characterised by primary succession communities that inhabit fresh lava surfaces until terminated by the next eruptive event, and it is assumed that longer volcanic hiatuses should lead to more mature plant communities. This expected succession trajectory is contradicted by palynological data which show that seral succession declines during the phase of waning CRPB volcanism and prolonged interbed intervals. Frequent volcanic activity and increased deposition of Snake River Plain hot spot ashes during this phase resulted in ecological disturbance of intra-lava field vegetation. This suggests that the CRBP flora was driven largely by extrinsic forcing, and implies that LIP volcanism of similar scale and magnitude to that of the CRBP had less environmental impact than understood as yet. This study supports the theory that past biotic extinctions were triggered by numerous factors rather than a single geological event.
Earth and Environmental Science Transactions of the Royal Society of Edinburgh
The Paleogene lava flows of the Faroe Islands Basalt Group are divided into three relatively thic... more The Paleogene lava flows of the Faroe Islands Basalt Group are divided into three relatively thick formations. The oldest, the Beinisvørð Formation is separated from the second lava flow succession, the Malinstindur Formation, by two formations composed primarily of volcaniclastic rocks. The oldest of these, the Prestfjall Formation has been interpreted as a period of eruptive quiescence and linked to changes in mantle melting. It is characterised in the south by the occurrence of coals, while the overlying Hvannhagi Formation is a sequence of primary and remobilised volcaniclastic strata. Field, laboratory, palynology, and photogrammetry studies have been used to investigate variations in facies and architecture within these volcaniclastic formations. The data reveal significantly different depositional systems in the Prestfjall and Hvannhagi formations over the ~40 km from the island of Vágar in the north to the island of Suðuroy in the south. Facies distribution in both the Prest...
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Papers by David Jolley