bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Victor Field, Blocks 49/17, 49/22, UK North Sea
Authors: Lambert Robert A. 
Published: April 2008

Abstract
The Victor gas field lies in the Southern North Sea Gas Province on the eastern flank of the Sole Pit Basin. The field straddles Blocks 49/17 and 49/22, and is situated approximately 140 km off the Lincolnshire coast. Victor was discovered in April 1972 and is operated by Conoco (UK) Ltd on behalf of BP, Mobil and Statoil. The structure is an elongated tilted fault block, trending NW-SE. The reservoir sands are contained in the Leman Sandstone Formation (Rotliegendes Group) of Early Permian age, and consist mainly of stacked aeolian and fluvial sands with a gross thickness of 400-450 ft across the field. Porosities vary from 16-20%, with permeabilities ranging from 10 md to 1000 md in the producing zones. Initial gas in place is estimated at about 1.1 TCF with recoverable reserves of the order of 900 BCF. The field was brought on-stream in October 1984, and the five producing wells deliver, on average, 200 MMSCFD through the Viking Field 'B Complex' to the Conoco/BP terminal at Theddlethorpe in Lincolnshire
The West Sole Field, Block 48/6, UK North Sea
Authors: Winter D. A. , King B. 
Published: April 2008

Abstract
West Sole is located in the Sole Pit area of the Southern North Sea Permian Basin in UK Block 48/6. The field was discovered in 1965 and was the first commercial discovery in the UK Continental Shelf. Gas Production commenced in 1967. Initial reserves are 1.873 TCF of which 1.335 TCF had been produced by the end of 1989. Gas is trapped in aeolian sandstones of the Permian Lower Leman Sandstone Formation. Three depositional facies are recognized, comprising aeolian dune, fluvial and sabkha. The aeolian dune facies form the principal reservoir sandstones, in units up to 40 m (131 ft) thick. However, permeability is reduced due to pervasive illite cementation, such that it averages 3 md in the dune sandstones. Productivity is enhanced in the southern part of the field by 'open' gas-filled fractures, generated during the Alpine inversion. The trap was also amplified at this stage and comprises a faulted inversion anticline trending NW-SE. The source rock is the Westphalian Coal Measures, lying directly beneath the reservoir.
The South Morecambe Field, Blocks 110/2a, 110/3a, 110/8a, UK East Irish Sea
Authors: Stuart I. A. , Cowan G. 
Published: April 2008

Abstract
The South Morecambe Gas Field has been developed as a seasonal supply field to boost supplies to the National Transmission System at times of peak demand. This mode of operation has led to a requirement for exceptionally high reliability in all aspects of the development. This requirement has prompted the generation of an accurate and comprehensive geological model so that reservoir performance can be predicted as reliably as possible, and that wells can be drilled in optimum locations. The exceptional shallowness of the structure (crest at -2400 ft TVSS, GWC -3750 ft TVSS), coupled with the need to drain the reservoir cost-effectively and to minimize the risk of well interference has led to the use of slant drilling techniques for the first time in European waters. The field is located in the East Irish Sea Basin. The Triassic Sherwood Sandstone Gp forms the reservoir, and the Mercia Mudstone Gp provides the seal. The reservoir sands were laid down in a rapidly subsiding basin under continental semi-arid conditions, and comprise a complex interplay of major channel-fill sandstones, secondary channel-fill sandstones associated with non-channelized sheetflood sandstones, and localized, very high permeability (> 1000 md) aeolian and reworked aeolian sandstones. A vertical organization of these facies has been observed, with some intervals dominated by channel deposition, others by non-channelized deposits, due to periodic adjustments of the whole basin, and this has permitted the establishment of a reservoir zonation. A complex diagenetic history is recognized, with several phases of dolomite and quartz cementation. Differential compaction is also a major control on the disposition of reservoir properties. The greatest control on permeability (but not porosity) is platy illite which formed beneath a palaeo-GWC at an early stage in the growth of the structure, and which gives rise to a diagenetic layering of the reservoir into a high permeability Illite-Free Layer and a deeper, low permeability Illite-Affected Layer. The data presented herein is based upon the results of development drilling on South Morecambe.
Early Precambrian crustal development: changing styles of mafic magmatism
Authors: Hall R. P. , Hughes D. J. 
Published: April 2008

Abstract
The work of Sutton & Watson (1951) was one of the cornerstones in the interpretation of the evolution of early Precambrian (Archaean and early Proterozoic) gneiss complexes and in the documentation of mafic dyke swarms that intruded recently accreted Archaean cratons. Since then, the concept of geological terranes and terrane accretion has been extended back to the Archaean, and different events can be distinguished by increasingly precise isotopic dating techniques. There is growing evidence that, with certain clear provisos, the principle of uniformitarianism can be applied as equally to the early Precambrian as it can through the rest of the geological record. In terms of mafic magmatism, there are similarities between some ancient and modern suites, both intrusive and extrusive, but there are also some major differences, such as the presence of komatiites in the Archaean and the formation of large-scale layered intrusions and extensive dyke swarms at the end of the late Archaean and in the early Proterozoic. The mantle has evolved continuously with the progressive extraction of mafic magmas but, allowing for this, continental tholeiites appear to have changed little with time. Ancient mid-ocean ridge basalts are elusive because of their poor preservation record. The geochemistry of mafic volcanics occurring in many greenstone belts commonly suggests a continental contamination component and that these volcanic rocks are most closely akin to those from present-day arc systems. The relative abundance of early Precambrian intrusive mafic suites parallels the crustal growth curve, reflecting the global crustal accretion-differentiation superevent towards the close of the Archaean. Bimodal tholeiitic-noritic mafic magmatism associated with many of these intrusive suites stems from this rapid turnover in the mantle-mafic crust-continental crust system. This, in turn, gives a possible link between the respective evolutions of Archaean to Recent komatiitic, noritic and boninitic suites.
W. Q. Kennedy, the Great Glen Fault and strike-slip motion
Authors: Bluck B. J. 
Published: April 2008

Abstract
At the time it was written, Kennedy’s paper on the Great Glen Fault had clear evidence for a known lateral displacement, and the evidence was so well presented that it convinced a sceptical geological world that such movements were possible. The acceptance of large scaled lateral movements led to the concept of great fundamental fractures and, with the advent of plate tectonics and a climate of mobilistic thinking, many of these great fractures were later recognized as plate or terrane boundaries.
Along with this thinking, new criteria evolved for recognizing those fractures that had been involved in major displacements—in fact the concept of throw became replaced by the concept of role. Role was identified from the history of the blocks on either side of the fracture, and where that history was incompatible with them being together, then a large role was possible for the fault itself.
Taking a new look at the Great Glen Fault in these terms, it becomes clear that there are insufficient data on the rocks on either side to allow any conclusions about the nature and timing of its role to be deduced. If the later, displacements, which are at present the main concern of researchers, are the sum of the movements on the fracture then it is ironically the least significant of the four NE-SW fractures in Scotland.
Triassic pebbles, derived fossils and the Ordovician to Devonian palaeogeography of Europe
Authors: Cocks L.R.M. 
Published: April 2008

Abstract
Papers published by Salter (1864) and Davidson (1870) on the faunas from pebbles in a Triassic conglomerate at Budleigh Salterton, Devon, are reviewed. After modern reassessment, these pebbles, although of apparently similar quartzites, have been found to be of four different ages, two Ordovician (mid-Arenig and late Llandeilo) and two Devonian (Lochkovian-Pragian and Frasnian). By comparing these four faunas with those contemporary in adjacent palaeocontinents, it can be shown that, apart from the earliest one, they have affinities closer to those of the Armorican peninsula of Brittany and Normandy than to the rest of Britain and that these Armorican faunas are in clasts which were transported northward by Triassic rivers. Consideration of all the various faunas in the whole of northwest Europe reflect the earliest Ordovician of southern Britain as part of the vast Gondwanan continent, from which it became detached by the mid-Ordovician, with a widening Rheic Ocean between the two palaeocontinents; and the subsequent merging of Avalonia with Baltica and Laurentia to form Laurussia by Mid-Devonian times. New palaeogeographical maps depicting phases from the Ordovician to the Devonian are presented.
Flood basalts versus central volcanoes and the British Tertiary volcanic Province
Authors: Walker George P. L. 
Published: April 2008

Abstract
A controversy in the final decades of the last century developed between Geikie and Judd over the nature of the volcanoes in the British Tertiary Province. Geikie regarded the lavas as in Antrim and Skye as plateau basalts (today called flood basalts) erupted from widely scattered fissures, while Judd regarded the intrusion complexes as in Central Mull and Skye as eroded stumps of major central volcanoes from which the lavas originated. Soon after, instigated by the controversy, British volcanology flowered for several decades in what may be called its ‘Classic Period’. Detailed mapping projects were undertaken, and new concepts were developed that are basic to volcanology. This paper views the controversy and its aftermath, and also briefly reviews recent conceptual developments in the North Atlantic Volcanic Province of which the British Tertiary rocks are a part. The paper discusses the present understanding of flood basalts and central volcanoes, and presents new criteria based on structural features of lava flows (such as the dependence of lava thicknesses, and the occurrence of pipe vesicles, on ground-slope angle) to distinguish between them. Magnetic fabric study of magma-flow directions in intrusions and lava flows, and palaeomagnetic study of post-emplacement tilting of igneous rocks, have great unrealized potential.
Magmatic differentiation
Authors: Wilson Marjorie 
Published: April 2008

AbstractDuring the past 150 years, a wide range of processes have been invoked to explain the mechanism by which magmas differentiate.These may be divided into those which operate essentially in the liquid state, such as liquid immiscibility and thermogravitational diffusion, and those which involve some form of crystal-liquid fractionation. It is now generally accepted that the latter are the most important. Many of the models developed during the past twenty years to explainmagmatic differentiationhave their roots in ideas first proposed in the early years of this century. This review presents some of the historical background to the subject and attempts to summarize some of the more recent developments.Alfred Harker’s perceptive study of in-situ crystallization within a high-level intrusion (Carrock Fell in the English Lake District), published in volume 50 of theQuarterly Journal of the Geological Societyin 1894, clearly laid the foundations for many modern theories. In 1900 he introduced the oxide–oxide variation diagram, which is still widely used to depict the geochemical variations within suites of cogenetic igneous rocks. Studies of phase equilibria in synthetic and natural systems by Bowen and his contemporaries, during the 1920s and 30s, provided the theoretical background needed to understand the complex processes involved in fractional crystallization of magmas. In the past decade mathematical modelling has allowed a more quantitative approach to the problem.
Carbonate magmas
Authors: Bailey D.K. 
Published: April 2008

Abstract

For 40 years, the case for the existence of carbonate magmas rested on field observations of carbonatite intrusions, in which the lack of thermal effects raised an apparent conflict with the high melting temperatures of pure carbonates. Since 1960, the position has changed, with the growth of experimental studies and increasing observations of effusive carbonate rocks. A nephelinite/phonolite volcano in Tanzania is currently erupting Na-Ca-K carbonate magma (around 600 °C). This is unlike all other intrusive and effusive carbonatites (350 examples worldwide) which are dominantly composed of Ca, Mg, Fe carbonates, and have negligible alkali contents. Although a number of effusive calcio-carbonatites are considered to be degraded alkali carbonatites, there are several examples (including one magnesio-carbonatite) which are close to their erupted composition, and substantiate the existence of high
T
carbonate magmas lacking essential alkalis at the time of eruption. In these associations silicate magmas are absent (or minor), and in most the effusive carbonatites have been erupted directly from the mantle (with entrained peridotite debris and minerals). They provide a link with the ultramafic association (peridotite and pyroxenite), seen in some carbonatite intrusions, with the commonly associated ultramafic lamprophyres (which may also carry mantle xenoliths), and with carbonate-rich kimberlites. Many carbonatite intrusions also have little or no associated silicate magmas, putting in question a popular view that carbonatites normally form only minor parts of alkaline igneous complexes of nephelinite/phonolite type. The corollary, that the carbonatites are normally differentiates is even less sound, because in alkaline complexes the carbonatite is always last in the eruption sequence. Here the carbonatite may represent the final residua expelled from the source region. Most large carbonatite intrusions seem to have been emplaced at lower
T
than effusives, probably as a near-solidus mush, with the interstitialfluid metasomatizing the country rocks. A wider perspective of carbonate magma genesis is called for, to encompass various kinds of differentiation from alkaline silicate magmas, and primary carbonate magmas from various depths in the mantle (with or without silicate melts). The strongly bimodal composition distribution of calcic and dolomitic carbonatites is a further factor awaiting explanation. Half of the known carbonatites are in Africa, and their timing and distribution indicate that the activity is a response to lateral forces acting across the plate. Carbonate magmatism is waiting to be unleashed. This activity demands attention because it is now clear that carbonate magmatism is a crucial surface expression of deep mantle processes.
The Sicilian gateway: anatomy of the deep-water connection between East and West Mediterranean basins
Authors: Reeder Michael S. , Rothwell Guy , Stow Dorrik A. V. 
Published: April 2008

Abstract
The Sicilian gateway is a narrow, deep, interconnected series of basins, sill valleys and passageways that cuts across the broad, shallow Sicilian-Tunisian Platform in the Central Mediterranean. This deep connection allows dense Levantine Intermediate Water (LIW) formed in the Eastern Mediterranean to flow in a westerly direction through the gateway and exit into the Tyrrhenian and Balearic basins of the Western Mediterranean. LIW is replaced by a strong surface flow of Modified Atlantic Water (MAW). A complex and still active tectonic regime has been an important control on the development of physiography and on the style and distribution of sediments across the Platform.
Within the deep gateway basins, turbidites, debrites and megabeds are intercalated with a background of predominantly muddy and calcareous, hemipelagic and contourite sediments. Evidence for the influence of bottom currents on sedimentation is seen in the construction of small mounded drifts and irregular patch drifts, in zones of scouring and non-deposition, in local photographic evidence of a current-smoothed or rippled seafloor, and as a subtle combination of features present in the background sediments. These include: extensively reworked microfossil assemblages, rare diffuse lamination, coarse lenses of mixed composition within a pervasively bioturbated sediment, and relatively high rates of accumulation.
The Columbia Channel-levee system: a fan drift in the southern Brazil Basin
Authors: Faugères J.-C. , Lima A. Franca , Massé L. , Zaragosi S. 
Published: April 2008

Abstract
The Columbia Channel is a turbiditic channel elongated W-E on the rise of the south Brazilian basin (4200 to 5000 m water depth). The whole area is swept by the northward flowing Antarctic Bottom Water. As a consequence, depositional processes have built a fan drift system. This system displays a levee along the northern flank of the channel while no levee occurs on its southern flank due to the Coriolis effect. The levee (400 km in length and 100 to 200 km in width) is bounded to the north by the Vitoria-Trindade Seamounts. It shows, first, a W-E trend parallel to the channel axis and predominantly turbiditic pattern, and then a S-N trend parallel to the rise contours with a predominant contouritic pattern. Its thickness is up to 1000 m. The distribution of sedimentary processes and associated deposits were investigated on the basis of water gun seismic and 3.5 kHz echosounding profiles, and core lithology. On the lower S-N part of the levee, the deposits consist of muddy contourites. On the shallowest part, turbidites that originate from the upper continental margin in the channel and on the southern part of the levee close to the channel, and from the Vitoria-Trindade Seamounts on the northern part of the levee, are interbedded with contouritic muds, and top-truncated silty turbidites. Areas subjected to turbidity current processes show chaotic to well-stratified, high amplitude reflections, in the subsurface, and more or less prolonged echofacies with or without sub-bottom reflectors, at the seabed. Areas subjected to contour currents show, in the subsurface, transparent seismofacies with some discontinuous low amplitude wavy reflections, and, in the surficial deposits, predominant wavy echofacies with sub-bottom relectors, frequently associated with tangential hyperbolae.
Contour currents, sediment drifts and abyssal erosion on the northeastern continental margin off Brazil
Authors: Gomes P. O. , Viana A. R. 
Published: April 2008

Abstract
Seismic reflection data collected as part of the Brazilian Continental Shelf Survey has allowed the recognition of large sediment drifts related to bottom currents along the continental rise off northeastern Brazil. Antarctic Bottom Water (AABW), which flows northward across a physiographic constriction - the hotspot-related Bahia Seamounts - has controlled the deposition of these contourite drifts. Following this pathway since the Middle Oligocene, AABW has also led to the formation of regional unconformities and the excavation of the 800 km long and up to 470 m deep Pernambuco Seachannel. This feature, which represents the 'trunk channel' of a complex submarine drainage system, flows into the Pernambuco Abyssal Plain, building a large fan-like deposit - the Pernambuco Countourite Fan. As observed elsewhere along continen–tal margins, the geometry of the sediment drifts alternates from mounded to sheeted, channel-related or confined, depending on the physiographic setting and on the velocity of the flow. The so-called 'modified drift-turbidite systems', formed by an interplay between downslope sediment gravity flows and alongslope bottom-current-controlled deposition, are well developed near the continental slope region, particularly in the Sergipe Basin, where the São Francisco River has built its deep-sea fan.
Evidence of bottom current influence on the Neogene to Quaternary sedimentation along the northern Campos Slope, SW Atlantic Margin
Authors: Viana Adriano R. , Hercos Cízia M. , De Almeida Waldemar , Magalhães José Luís , De Andrade Sinara B. 
Published: April 2008

Abstract

Geophysical and sedimentological data indicate that bottom currents have played a fundamental role in deposition along the Campos continental slope, especially during the Neogene and Quaternary. Sediment drifts are clearly observed in 2D and 3D seismic data. The external geometry and internal reflection pattern of these drifts suggest the predominant action of northward-flowing currents (Southern Ocean Current) along the middle and lower slope (650-1200 m). Upper Quaternary sediments within that zone are composed of highly bioturbated, silty to sandy mud, with rare lamination and no other primary structures. On the upper slope, below the southward flowing Brazil Current, sub-bottom profiles and side-scan sonar records indicate the development of several bedform styles. On the uppermost slope, between 200-300 m, longitudinal lineations and transverse bedforms (2D and 3D dunes) are observed. Sediments are siliciclastic to mixed silty to muddy sand, with rare primary traction structures preserved. Downslope, from 300 to 650 m, linear crested bedforms, a few metres high (2-7 m) are developed. In this zone, an alongslope similarity in the depositional style over more than 50 km suggests bottom current control on sedimentation. The deposits are composed of 1 m of silty muds overlying a decimetric layer of silty sand that grades downslope to a highly oxidized, bioturbated, fine-grained interval. The variability of sediment accumulation rate (2 to 30 cm ka
_1
) is related to high frequency temporal and local modifications
Contourite sedimentation in the Falkland Trough, western South Atlantic
Authors: Cunningham Alex P. , Howe John A. , Barker Peter F 
Published: April 2008

Abstract
The Falkland Trough is a west-east bathymetric deep that separates the Falkland Plateau from the North Scotia Ridge in the western South Atlantic. It lies in the path of Circumpolar Deep Water flowing within the Antarctic Circumpolar Current (ACC), and Weddell Sea Deep Water flowing beneath the ACC east of Shag Rocks passage. Marine geophysical and sediment core data demonstrate the influence of ambient bottom currents on deposition in this area, and reveal two styles of contourite sedimentation: (1) deposition of glauconite-rich sandy contourites in exposed areas of the Falkland Plateau and Falkland Trough, where vigorous ACC bottom currents control sedimentation, and (2) deposition of biogenic sandy contourites, muddy contourites and hemipelagites (western Falkland Trough), and muddy diatom ooze (eastern Falkland Trough), in the form of two elongate sediment drifts, which have developed in the presence of more sluggish bottom currents. The drift sediments contain a depositional record of bottom current flow through the glacial cycle (southern-origin bottom water flow in the east, and probably ACC flow in the west); analyses of core data from the western Falkland Trough suggest a reduction in bottom current strength during the Last Glacial Maximum at present depths of > 2500 m below sea level.