bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neogene uplift and erosion of southern Scandinavia induced by the rise of the South Swedish Dome
Authors: Japsen Peter , Bidstrup Torben , Lidmar-Bergström Karna 
Published: April 2008

Abstract

Basin modelling and compaction studies based on sonic data from the Mesozoic succession in 68 Danish wells were used to estimate the amount of section missing due to late Cenozoic erosion. The missing section increases gradually towards the coasts of Norway and Sweden from zero in the North Sea to
c.
500 m in most of the Danish Basin, but over a narrow zone it reaches
c.
1000 m on the Skagerrak-Kattegat Platform in northernmost Denmark. The increasing amount of erosion matches the increase in the hiatus at the base of the Quaternary, where Neogene and older strata are truncated, and the Mesozoic succession is thus found to have been more deeply buried by c. 500 Paleocene-Miocene sediments in large parts of the area. These observations suggest that the onset of erosion occurred during the Neogene, and that the Skagerrak-Kattegat Platform was affected by tectonic movements prior to glacial erosion. In southern Sweden just east of the Kattegat, the exposed basement of the South Swedish Dome attains altitudes of almost 400 m. The formation of the Dome started in the Late Palaeozoic, but geomorphological investigations have led to the conclusion that a rise of the Dome occurred during the Cenozoic. We find that the pattern of late Cenozoic erosion in Denmark agrees with a Neogene uplift of the South Swedish Dome and of the Southern Scandes in Norway. This suggestion is consistent with major shifts in sediment transport directions during the late Cenozoic observed in the eastern North Sea, and with formation of a new erosion surface as well as re-exposure of sub-Cambrian and sub-Cretaceous surfaces in southern Sweden. The Neogene uplift and erosion of southern Scandinavia appears to have been initiated in two phases, an early phase of ?Miocene age and a better-constrained later phase that began in the Pliocene. Neogene uplift of the South Swedish Dome with adjoining areas in Denmark fits into a pattern of late Cenozoic vertical movements around the North Atlantic.
Cenozoic evolution of the Faroe Platform: comparing denudation and deposition
Authors: Andersen Morten Sparre , Sørensen Aage Bach , Boldreel Lars Ole , Nielsen Tove 
Published: April 2008

Abstract

Throughout Paleocene and Eocene time the Faroe-Shetland Channel and the eastern part of the Faroe Platform was a subsiding marine basin. In Early Paleocene time, basin-floor fans of a British provenance were deposited in the eastern part of the basin. In Late Paleocene time,
c.
6 km of basalt entered the basin from the west and north, and the basin was constricted by the large volumes of basalt that entered the basin, creating the Faroe-Shetland Escarpment. In Eocene time subsidence continued in the basinal areas. Again, sediments of a dominantly eastern provenance were deposited. Throughout Eocene time, erosion products from the Faroe Platform were possibly deposited in the Faroe Bank Channel and the Norwegian Sea Basin, but only to a limited degree in the Faroe-Shetland Channel. The oldest sediments of documented western provenance on the eastern margin of the Faroe Platform are of Early Oligocene age. During a compressional phase commencing in Mid-Late Miocene time some basinal areas emerged and erosion took place on the top of emerged anticlines. However, denudation throughout Late Miocene and Early Pliocene time was apparently rather limited compared with a Late Pliocene phase of denudation. During this phase of denudation, a large progradational wedge was deposited on the eastern margin of the Faroe Platform. On the basis of a structural analysis of the Faroe Platform, the amount of basalt removed from it during Cenozoic time is estimated to be
c.
46 000 km
3
(131 100 × 10
12
kg). Using 2900 kg m
−3
as the density of basalt and 2300 kg m
−3
as sediment density the estimated amount of removed basalt is in fair agreement with the estimate of the volume of sediments derived from the platform (
c.
56 000 km
3
, 114 800 × 10
12
kg). The greatest deposition rates on the eastern Faroe Platform and in the Faroe-Shetland Channel apparently occurred after two distinct inversion or compression events in Mid-Eocene and Mid-Late Miocene time. However, uplift of the Faroe Platform could have been forced by denudation rather than endogenous processes.
The post-Variscan thermal and denudational history of Ireland
Authors: Allen Philip A. , Bennett Stuart D. , Cunningham Michael J. M. , Carter Andy , Gallagher Kerry , Lazzaretti Eric , Galewsky Joseph , Densmore Alex L. , Phillips W. E. Adrian , Naylor David , Hach Cristina Solla 
Published: April 2008

Abstract

The thermal and denudational history of Ireland is evaluated using an extensive new apatite fission-track (AFT) dataset derived from surface samples. Modelled thermal histories are used to construct maps of denudation for a number of time slices from Triassic time to 10 Ma using a time-dependent palaeogeotherm. The maps illustrate the spatial variability of denudation and subsidence within each time slice. The patterns of denudation are complex, showing considerable variability at the length scale of 10
1
–10
2
km, with especially high denudation rates found over known igneous centres such as the Mournes of County Down. Based on the onshore AFT data alone, there is no definitive signature of an Irish Sea Dome extending significantly across Ireland in Early Tertiary time. The cumulative amount of denudation during Tertiary time varies depending on the AFT annealing model used, but is generally in the region between 1 and 2 km and without clear spatial trends. High amounts of denudation have been mapped over the Tertiary intrusions in County Down, reflecting their unroofing since emplacement in Paleocene time. The cumulative denudation from Triassic time to 10 Ma shows relatively low amounts of denudation (<2 km) in the Irish Midlands and the extreme NE of the island, consistent with the observation that Mesozoic-Tertiary sediments and igneous products are preserved in the Ulster Basin. The western flank of Ireland and the region between Dublin and County Down show high cumulative amounts of denudation (<4 km), the latter being consistent with the high amounts of denudation interpreted for the Irish Sea region. This denudation pattern explains in part the outcrop of Precambrian and Lower Palaeozoic rocks in these areas. The spatial integration of the denudation over the entire landmass gives the average denudation rate and the sediment discharge from Ireland as a function of time. Average denudation rates are moderately high in Triassic time, falling to low values in Cretaceous time, and increasing substantially in Tertiary time. However, the total volumetric discharge of sediment in Tertiary time is an order of magnitude smaller than the preserved solid volume of Tertiary sediment in the basins offshore western Ireland.
Diagenesis and fluid flow in response to uplift and exhumation
Authors: Parnell John 
Published: April 2008

Abstract
Uplift of sedimentary rocks is accompanied by a wide range of physical and chemical changes that contribute to diagenesis and modify fluid flow regimes. Topography becomes a major driving force behind fluid flow patterns, and meteoric water may penetrate to several kilometres below the surface. Typical diagenetic processes include alteration and leaching of feldspars and other unstable minerals, precipitation of iron oxides and kaolin, and leaching of carbonate and sulphate cements. Reservoired oil may be degraded by near-surface waters, but reservoir rocks may become more oil-wet.
Brittle fracturing is enhanced near the surface, and fluid flow may become predominantly fracture-bound as fractures dilate. Uplift also causes tilting of fluid contacts and remigration of hydrocarbons. Exsolution and expansion of gas similarly causes remigration of oil to peripheral traps.
Although basin uplift is generally regarded as being detrimental to hydrocarbon prospectivity, especially as a result of breaching of traps, there is also an enhanced potential for hydrocarbon plays based on reserves of exsolved gas, condensate dropout, peripheral traps and fractured reservoirs.
Uplift-related hydrocarbon accumulations: the release of natural gas from groundwater
Authors: Cramer Bernhard , Schlömer Stefan , Poelchau Harald S. 
Published: April 2008

Abstract
Vertical tectonic movements often change the structural style and physicochemical habitat of sedimentary basins. Changes in pressure, temperature and salinity of the groundwater caused by tectonic uplift may result in the release of previously dissolved gas. This process of gas exsolution from groundwater is shown to be an important mechanism in the formation of gas accumulations in uplifted basins. Two principal types of gas release are discussed. A hydrodynamic type is active when groundwater flows into areas of lower pressure or mixes with water of different temperature or salinity. It is anticipated that this effect is more of local importance, but over long periods of groundwater flow large volumes of gas may be exsolved. The hydrostatic type of gas release can occur in any sequence of sedimentary rocks where uplift causes a drop in pressure and temperature. This phenomenon may act basin-wide. Mass balance calculations show that the largest gas accumulations on Earth, such as the Urengoy field in West Siberia, could have been formed by this process.
Depressurization of hydrocarbon-bearing reservoirs in exhumed basin settings: evidence from Atlantic margin and borderland basins
Authors: Corcoran D. V. , Doré A. G. 
Published: April 2008

Abstract
Depressurization of reservoirs in petroliferous basins commonly occurs through cap-rocks at structural crests where pore pressures are locally elevated because of either the presence of a hydrocarbon column or the redistribution of overpressures by water flow along laterally extensive inclined permeable aquifers. In exhumed petroliferous basins this deflation of excess pore pressures is enhanced by the denudation process, which results in the large-scale removal of overburden during regional uplift. Evidence from the exhumed basins of the Atlantic margin indicates that hydrocarbon accumulations in these basins are commonly characterized by underfilled traps and hydrostatically pressured or modestly overpressured reservoirs. These observations are reviewed in the context of the generic mechanisms by which top-seals leak, the properties of cap-rocks and the physical processes that occur during exhumation.
Water-wet shaly cap-rocks can form a capillary seal to a hydrocarbon column while simultaneously accommodating brine flow and equilibration of pressures between the reservoir and the top-seal. In contrast, thick, low-permeability shale or evaporite sequences may form pressure seals that restrict vertical brine and hydrocarbon flow and prevent the equilibration of aquifer pressures above and below the seal. In any sedimentary basin, the presence of regional pressure seals can result in a layered hydrogeological regime with hydrostatically pressured strata decoupled from over- or underpressured cells. Recently exhumed basins typically show limited overpressuring and in a number of these basins underpressured reservoirs have been described. Post-exhumation overpressure generation is primarily driven by tectonic compression, aquathermal pressuring and hydraulic head.
The fluid retention capacity of any cap-rock lithology during exhumation is dependent upon the physical and mechanical characteristics of the cap-rock at the time of exhumation and the timing and conditions of the associated deformation relative to the timing of hydrocarbon emplacement. The permeability and deformational characteristics of halite render it an excellent cap-rock with a high retention capacity, even under conditions of exhumation. However, mudrocks may also form effective cap-rocks in exhumed basins when the deformation associated with exhumation occurs before embrittlement and the shale cap-rock exhibits ductile behaviour.

Shale and evaporite cap-rocks form the main regional seals to hydrocarbon accumulations in exhumed basins of the Atlantic margin and borderlands.
Syn-exhumation
top-seal efficiency (fluid retention capacity) is a major exploration risk in these basins, although
post-exhumation
top-seal integrity in these basins may be relatively high under certain conditions. Consequently, a major exploration risk factor in exhumed basin settings pertains to the limited hydrocarbon budget available post-regional uplift and the efficiency of the remigration process.
Continental margin off Norway 62–75°N: Palaeogene tectono-magmatic segmentation and sedimentation
Authors: Eldholm O. , Tsikalas F. , Faleide J. I. 
Published: April 2008

Abstract
The development of rifted and sheared segments on the Norwegian continental margin between 62 and 75°N is spatially related to a distinct along-margin segmentation which is governed by transfer zones formed during the Late Jurassic-Early Cretaceous rift episode. In fact, these structures may represent a repeated structural inheritance going back to the Proterozoic. Complete lithospheric breakup near the Paleocene-Eocene transition was preceded by a rift episode which was probably initiated in the early to middle Campanian. It culminated with a massive, regional magmatic event during breakup characterized by eruption of thick lava sequences covering large areas along the continent-ocean transition. The Norwegian volcanic margin belongs to the North Atlantic Large Igneous Province formed by impingement of the Iceland plume on a lithosphere under extension. Offsets in the initial plate boundary, combined with late rift uplift and subsequent construction of emerged marginal highs during breakup, provide key constraints on the Palaeogene water mass circulation, basin evolution and sedimentation during a period of progressive environmental deterioration following early Eocene greenhouse conditions.
Volcanic stratigraphy of the southern Prinsen af Wales Bjerge region, East Greenland
Authors: Hansen H. , Pedersen A. K. , Duncan R. A. , Bird D. K. , Brooks C. K. , Fawcett J. J. , Gittins J. , Gorton M. , O’Day P. 
Published: April 2008

Abstract

The volcanic succession in the inland Prinsen af Wales Bjerge contains the oldest known onshore lava flows (61 Ma) of the Palaeogene East Greenland flood basalt province. These flows and interbedded sediments define the Urbjerget Formation and are found in the southernmost part of Prinsen af Wales Bjerge. Flows of the Urbjerget Formation are chemically similar to the coastal Vandfaldsdalen Formation flows and the two formations may be chronostratigraphical equivalents. The Urbjerget Formation is overlain by the < 57 Ma tholeiitic basalts of the Milne Land Formation. Four regional volcanic formations are found along the Blosseville Kyst, but the Milne Land Formation is the only one present in the southern Prinsen af Wales Bjerge. Flows of the absent formations (Geikie Plateau, Rømer Fjord and Skrænterne formations) may not have been able to enter the area due to local uplift, more distal located eruption sites or possibly topographic features. A high-Si (SiO
2
> 52 wt%) lave flow succession in the Milne Land Formation consists of crustally contaminated magmas which were arrested in crustal chambers as the magma supply rate from the mantle decreased, either due to a general lowering of potential mantle temperatures or a decrease in the rate of continental rifting. Tholeiitic high-Ti flows (MgO: 10–15 wt%, TiO
2
: 5–6 wt%) within the Milne Land Formation are unique to the Prinsen af Wales Bjerge region, and equivalents have not been reported from other flood basalt provinces. Local flow composition variations in the Milne Land Formation can be explained as the result of melting under lithosphere of variable thickness, small-scale variations in mantle composition and mixing in small magma chambers. Unconformably overlying the Milne Land Formation is a succession of
c.
53 Ma alkaline flows, known as the Prinsen af Wales Bjerge Formation. Several crater sites are known from this flow succession and this suggests that the Prinsen af Wales Formation was only covered locally by later volcanic or sedimentary units. The duration of alkaline volcanic activity in the Prinsen af Wales Bjerge is not well constrained but may have been less than 2.5 Ma. The hiatus between the Urbjerget and Milne Land formations is a regional feature in the North Atlantic as it occurs at a similar stratigraphic level at Nansen Fjord, the Faroe Islands and in the ODP Leg 152 volcanic succession off SE Greenland at
c.
63°N. It represents a 3–4 Ma long cessation of, or very low frequency of activity in East Greenland/Faroese volcanism and may be explained as the time interval between two pulses in the palaeo-Icelandic plume.
The stratigraphy, environment of eruption and age of the Faroes Lava Group, NE Atlantic Ocean
Authors: Ellis David , Bell Brian R. , Jolley David W. , O’Callaghan Michelle 
Published: April 2008

Abstract

Palaeogene volcanism on the NW margin of the Faroe-Shetland Basin is represented by the Faroes Lava Group, within an age range of 57.5–60.56 Ma. The volcanic sequence comprises >1000 m of basaltic volcaniclastic rocks deposited in estuarine or marginal lagoons, overlain by three laterally-extensive formations of subaerial facies basaltic lavas: Lower,
c.
3250 m; Middle,
c.
1400 m; Upper, at least 900 m (top not preserved). The Lower and Upper formations comprise high-volume sheet flows, commonly with ferrallitized tops, interbedded with reddened, thin, fluvial claystone and basaltic siltstone deposits. Laterally-impersistent coals occur within the Lower Lava Formation. The Coal-bearing Formation (
c.
20 m) was deposited in an overbank floodplain environment during an hiatus in the volcanism between the Lower and Middle formations. The Volcaniclastic Sandstone Sequence comprises hydroclastic and pyroclastic deposits which post-date the Coal-bearing Formation and represent a return to volcanism, prior to the eruption of the Middle Lava Formation which is mainly characterized by inflated pahoehoe flows. The onshore sequence of the Faroes Lava Group can be correlated with basaltic flows within the Faroe-Shetland Basin, where lavas in Well 205/9-1 are interpreted to be of Lower Lava Formation affinity, possibly erupted from a local vent system. Seismic and gravity mapping and modelling suggest that the offshore extension of the Lower Lava Formation, together with the oldest part of the Middle Lava Formation, comprise subaqueous hyaloclastites deposited in a prograding Gilbert-type lava delta system. The youngest part of the Middle Lava Formation and all of the Upper Lava Formation occur as subaerial facies lavas within the basin.
Coalfield closure and environmental consequence — the case in south Nottinghamshire
Authors: Robins N. S. , Dumpleton S. , Walker J. 
Published: April 2008

Abstract
The strata within and above the South Nottinghamshire Coalfield dip gently towards the east. There are many abandoned shallow workings in the western area where the coalfield is exposed, but to the east the coalfield is concealed beneath Permo-Triassic strata. The coalfield has yet to suffer closure, mine water rebound and the acid mine drainage (AMD) cycle. A very large area has been exploited with complicated internal drainage systems dependent on the maintenance of existing pumping regimes. An evaluation of the AMD threat has been carried out with particular regard to the risk posed to the Sherwood Sandstone aquifer, which overlies the concealed part of the South Nottinghamshire Coalfield. The evaluation has been assisted by three-dimensional (3-D) visualization that has enabled lumping of plentiful mine abandonment data, and predictive runs using the University of Newcastle GRAM model. These studies indicate that the critical spill-over elevation is 41 m above Ordnance datum (aOD), and that the aquifer will be at risk about 20 years after pumping ceases from the Coal Measures.
The hydrogeochemical dynamics of mine pit lakes
Authors: Bowell R. J. 
Published: April 2008

Abstract
On cessation of mining open pits or opencast workings that extend below the water table are likely to fill with water and thus develop a mine pit lake (MPL). This body of water remains as a permanent feature on the mine site and as such becomes a closure issue with respect to water quality and potential to degrade groundwater. Further, it may present a risk to the environment through the development of poor quality water with elevated concentrations of metals, metalloids, sulphate and depressed pH.
The prediction of future pit lake water quality within a MPL is, therefore, essential in considering environmental impact on a closed or abandoned mine facility. The controls on a MPL will vary over time, and will involve chemical, biological and physical processes. Localized and regional-scale processes affect these in turn. Consequently, in order to predict pit lake water quality it is essential to understand the hydrogeological, geochemical and limnological processes that influence water quality.
Secondary minerals in the abandoned mines of Nenthead, Cumbria as sinks for pollutant metals
Authors: Nuttall C. A. , Younger P. L. 
Published: April 2008

Abstract
Direct observations made during underground hydrogeochemical surveys of abandoned lead-zinc mines has highlighted the precipitation of secondary zinc minerals within abandoned lead-zinc mine workings in the north Pennines. Chemical analysis of mine waters has shown that molar concentrations of sulphate exceed those of zinc by two or three orders of magnitude, although they are released in equimolar proportions following the weathering of sphalerite. The excess of sulphate over zinc indicates that there must be significant sinks for zinc within the mine workings. Secondary zinc mineral sinks (principally hydrozincite and smithsonite) are the most likely explanation for the deficit in molar zinc concentrations and these minerals have been identified underground. In addition to the secondary zinc minerals, secondary calcite and aragonite from the workings have also been shown to provide sinks for zinc (by coprecipitation and solid-solution incorporation of zinc in these minerals). Calculation of the molar quantities of zinc and sulphate involved showed that as little as 5% of the zinc, weathered daily from the mineral deposits within the workings, is found to leave the mine dissolved in the mine water. However, this is sufficient to adversely impact the ecology of the receiving waters of the River Nent, which currently receives five circumneutral zinc-rich mine water discharges and drainage from a disused aqueduct.