bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small seismic-scale fault identification and mapping
Authors: Townsend C. , Firth I. R. , Westerman R. , Kirkevollen L. , Hårde M. , Andersen T. 
Published: April 2008

Abstract
The primary focus of this paper is to emphasise the large volumes of information related to faults and fault systems that are present in, and extractable from, 3D seismic data. During most interpretations, this information is seldom included and transferred to the reservoir model so that their effects can be accounted for during reservoir simulation. Reasons why they are not included are generally related to the time constraints imposed on studies when commercial considerations are often given precedence above any scientific justification. The inadequacies of what are presently considered acceptable models are highlighted and methodologies that could lead to improved reservoir models are proposed. These methodologies are derived from an investigation of how fault systems will manifest themselves in seismic data, based on both theoretical concepts and the use of synthetic models. From these information sources, principles are derived for the identification of faults and fault systems in 3D seismic volumes. These principles are then tested in two case studies selected to emphasize the limitations imposed on seismic resolution by both target depth and seismic frequency content. After highlighting the diversity of fault related information, which is accessible and currently under-utilized by current reservoir modelling techniques, potential methods for automatic mapping and digital extraction of fault information are proposed. When these automated methods are implemented into seismic interpretation software, commercial reasons for ignoring small seismic-scale faults will be significantly reduced and as a result, reservoir performance predictions will become more realistic.
Space and time propagation processes of normal faults
Authors: Marchal D. , Guiraud M. , Rives T. , van den Driessche J. 
Published: April 2008

Abstract
Studies of normal fault development in space and time by X-ray tomography imaged analogue modelling suggest that different processes occur during the propagation of these faults. The conceptual model proposed distinguishes two types of propagation: horizontal and vertical. Examination of horizontal propagation reveals two separate levels of organization. Firstly, an isolated fault segment develops, alternately over time, by radial propagation and by linkage with secondary fault segments (tip faults) arising at the end of the main fault segment (parent fault). These are arranged either in an en echelon or stepwise pattern. Secondly, isolated faults evolve by linkage. Two isolated faults connect up via a relay fault area which arises in the relay zone of the two isolated faults. The relay faults develop by radial propagation and link with the two major faults. Undulating fault traces result from propagation by tip-to-parent fault segment linkage or isolated-to-isolated fault linkage. Upward and downward vertical propagation are identified and exhibit equivalent propagation processes to those involved in horizontal propagation. Space-time sequences combining horizontal and vertical propagations over time suggest that the evolution of normal faults observed in space also reflects their evolution over time.
Quaternary neotectonism and intra-plate volcanism: the Coorong to Mount Gambier Coastal Plain, southeastern Australia: a review
Authors: Murray-Wallace C. V. , Belperio A. P. , Cann J. H. 
Published: April 2008

Abstract

The Coorong to Mount Gambier Coastal Plain in southeastern South Australia preserves a lengthy record of Quaternary temperate carbonate sedimentation in the form of high wave energy barrier shoreline deposits and associated back-barrier lagoon facies. The barriers occur sub-parallel to the modern coastline and to each other and increase in age landwards. The age of the barriers is now generally well established within a framework of radiocarbon, thermoluminescence, uranium-series disequilibrium, amino acid racemization dating and the position of the Brunhes-Matuyama boundary between the East and West Naracoorte Ranges. This framework is in accord with the deep-sea δ
18
O record of global ice volume change and the inferred timing of sea-level highstands for this interval. Individual barriers such as the last interglacial Woakwine Range (oxygen-isotope substage 5e) may be traced laterally for distances up to 300km and record a history of neotectonism in the form of regionally varying epeirogenic uplift associated with Quaternary volcanism.
The Namib Rift: a rift system of possible Karoo age, offshore Namibia
Authors: Clemson J. , Cartwright J. , Swart R. 
Published: April 2008

Abstract
This paper describes a hitherto poorly documented, deep-seated rift system offshore Namibia, here named the Namib Rift. The structural history and rift geometry of this system are determined from reflection seismic data. No wells penetrate the rift-fill succession but from its stratigraphic context, regional thickness relationships and by analogy with onshore Karoo stratigraphy, the age of the rift is interpreted as broadly equivalent to the Karoo Supergroup. The rift is divisible into two major arms, with rift segmentation evident in the north. An angular unconformity separates a rift and post-rift sequence. This is interpreted as a Mid-Triassic hiatus related to a regional compressional events. The basement comprises the Pan-African Fold Belt along the coast, with the Damaran arm extending inland. In the Cape Cross-Walvis Bay area, the Autseib Lineament separates the Kaoko and Damaran arms. This lineament, and the adjacent basement fabrics, are shown to have strongly influenced rift geometry in this area. South of the Autseib Lineament, Damaran basement fabrics largely determined fault trends within the Namib Rift. To the north, Kaoko basement fabrics strongly influenced basement extensional faulting. This area was also subjected to Mid-Triassic compression. South of the Autseib Lineament, large-scale uplift was distributed across large folds whereas to the north, uplift occurred close to pre-existing faults. North-northeast directed compression was common to both areas, but the Autseib Lineament partitioned the structural response. McKenzie-type pure shear extension is favoured as the rift mechanism, with Mid-Triassic uplift modifying thermal subsidence. The final compressive event of the Cape Orogeny, coeval with the regional Mid-Triassic hiatus, terminated rifting in offshore Namibia.
Falkland Plateau evolution and a mobile southernmost South America
Authors: Barker P. F. 
Published: April 2008

Abstract
Assessment of southwest Gondwana break-up and its implications for regional hydrocarbon prospectivity must now take into account the origin of the southeast margin of the Falkland Islands as a volcanic rifted continental margin, and of the floor of the major part of the Falkland Plateau Basin as elevated oceanic crust. A reconstruction of the Falkland Plateau against southern Africa shows a southward extensional widening of the Outeniqua Basin across the line of the Falkland-Agulhas Fracture Zone, changing from stretched continental to oceanic crustal structure. Such a model for Outeniqua Basin opening, and the independent westward and clockwise rotation of the Falkland Islands block, suggests that southernmost South America was also a collection of microplates moving independently within a generally extensional environment in the Late Triassic-Early Jurassic. This is incompatible with assumptions of a rigid southernmost South America over this time, and a dominant role for a continuous dextral strike-slip Gastre Fault.
Evidence for multi-phase rifting in the North Falklands Basin
Authors: Bransden P. J. E. , Burges P. , Durham M. J. , Hall J. G. 
Published: April 2008

Abstract
The post-Gondwanide basin development of the North Falklands Shelf has been evaluated using seismic sequence stratigraphy to determine the structural and stratigraphic evolution of the region.
Two areally distinct post-Gondwanide basin systems (megasequences) are identified on the North Falklands Shelf, each with an independent structural and stratigraphic history. This contrasts with published models which interpret all basin areas to have been initiated in the early-mid Jurassic.
Megasequence I is developed in a series of northwest and subsidiary north and east trending half-graben, and typically shows sedimentary growth into faults indicating an active rifting environment. Pervasive small-scale synthetic faulting is largely non-rotational, suggesting that it represents later deformation. No post-rift sediments associated with this phase of extension are identified. Comparisons with seismic geometries of other basins in the region, based on a restored plate model, indicate that Megasequence I represents part of a widespread mid-late Jurassic rifting event, ultimately leading to the opening of the Rocas Verdes (oceanic) Basin.
Megasequence I is cross-cut by a north trending half-graben system which represents a failed arm of the South Atlantic Rift. The sedimentary fill of this basin, Megasequence II, can be subdivided into two units. The lower unit locally demonstrates sedimentary growth into the main eastern bounding fault of the half-graben and is thought to represent the synrift phase of Atlantic extension. Within the upper unit of Megasequence II there is no evidence of fault-controlled sediment growth into the main easterly bounding fault and the overall geometry is indicative of passive fill of pre-existing topography, supporting a post-rift origin for this section.
Similar seismic geometries are observed in parts of the North Atlantic Rift System and the northern North Sea. In particular, the North Shetland Basin has a Permo-Triassic to late Jurassic rift and post-rift section. Renewed extension in the early Cretaceous resulted in break-up and domino faulting, with the generation of high relief fault blocks. The intervening lows were sites of deposition for onlapping deepwater sediments.
Structural controls on the hydrocarbon and mineral deposits within the Kutai Basin, East Kalimantan
Authors: Colke I. R. , Craig J. , Blundell D. J. 
Published: April 2008

Abstract
The Kutai Basin, Kalimantan, is the deepest sedimentary basin in Indonesia. It contains both substantial reserves of hydrocarbons and minerals. The basin formed in the middle Eocene as a result of extension linked to the coeval opening of the Philippines Sea, the Celebes Sea and the Makassar Straits. Seismic profiles across the northern margin of the Kutai Basin reveal inverted half-graben of middle Eocene age oriented north-northeast-south-southwest and north-south. Further extension during the late Oligocene occurred on northwest-southeast trending extensional faults, reactivating basement structures. Restoration of deformed half-graben suggests that the syn-rift sequence, which contains important coal horizons, was sufficiently deeply buried to generate hydrocarbons prior to inversion. Shortening from the early Miocene to the present day resulted in breaching of some structural and stratigraphic traps, and also in the generation of new traps, in particular folds in the hanging walls of inverted half-graben and as a result of short-cut faults. Middle Eocene, late Oligocene-early Miocene and Plio-Pleistocene volcanic activity was focused at the intersection of basement weaknesses and set up hydrothermal systems which formed several mineral deposits. Reactivation of northwest-southeast and northeast-southwest trending basement structures as a result of a variation in the stress regime has controlled the location of hydrocarbon and mineral deposits in the Kutai Basin. This study highlights the importance of a regional understanding of varying stress regimes in controlling the orientation and location of structures active in a basin at a particular time, and in predicting the location of mineral deposits.
Extensional faults that localize Irish syndiagenetic Zn-Pb Deposits and their reactivation during Variscan compression
Authors: Hitzman Murray W. 
Published: April 2008

Abstract
The syndiagenetic Zn-Pb deposits of south-central Ireland, which are hosted by Lower Carboniferous carbonate sediments, occur along generally northeast trending, segmented normal fault arrays which were active during sedimentation. Individual sulphide bodies are located at points of maximum throw on east-west trending faults within the northeast trending fault arrays. All of the known major Irish Zn-Pb deposits in the south-central Midlands occur on north-side-down normal faults. The Irish Midlands underwent compressive shortening during the Variscan phase of the Hercynian orogeny. North-side-down normal faults were largely unaffected by this event while favourably oriented, south-side-down, Early Carboniferous normal faults were reactivated and transformed into reverse faults. The absence of significant sulphide deposits along south-side-down Chadian-Arundian extensional faults is probably due mainly to dismemberment, and/or compressional uplift and erosion, of such zones during Variscan deformation.
Fracture-controlled fluid flow in the Lower Palaeozoic basement rocks of Ireland: implications for the genesis of Irish-type Zn-Pb deposits
Authors: Everett C. E. , Wilkinson J. J. , Rye D. M. 
Published: April 2008

Abstract
A fluid inclusion study has been carried out to test whether circulation of fluids within fractured very low grade metasedimentary basement rocks was an important process in the genesis of the carbonate-hosted base metal deposits of Ireland. In the Silvermines district, Silurian greywackes and mudrocks are host to several different cross-cutting vein types which are locally abundant in east-east-northeast and northwest-north-northwest trending, high angle, brittle fault zones. Structural analysis indicates that the vein orientations are consistent with formation under a northeast-southwest dextral trans-tensional regime, controlled locally by reactivation of pre-existing faults. Three vein types have been identified: (1) early hematitic calcite-quartz ± pyrite; (2) quartz-calcite ± sphalerite, galena, chalcopyrite, pyrite, barite; (3) ankerite-ferroan dolomite-quartz ± sphalerite, pyrite. Vein types 2 and 3 are associated with weak to locally intense sericite-chlorite-carbonate alteration.

Primary fluid inclusion data from vein Types 2 and 3 show homogenization temperature-salinity characteristics (123–238°C, 9.7–20.6 wt% NaCl equivalent) overlapping significantly with the deposit data. In addition, primary inclusions hosted by quartz and sphalerite commonly contain CO
2
as indicated by the formation of gas clathrate and, rarely, solid CO
2
on cooling. Bulk fluid inclusion analyses on quartz vein samples show that the fluid composition is comparable with experimental data on fluids equilibrated with greywackes at temperatures of 200–350°C. Alkali geothermometry gives temperatures (158–219°C) not significantly different to homogenization temperatures suggesting that the veins formed under low fluid pressures.

New inclusion data from Navan brown sphalerite confirm the importance of a relatively high temperature, moderate salinity (187–220°C, 15–18 wt% NaCl equivalent) mineralizing fluid as observed at Tynagh, Silvermines, Lisheen and in the Lower Palaeozoic basement. In these inclusions, gas clathrate has been identified. This is the first reported occurrence of this phase in fluid inclusions from the Irish base metal deposits.
These data provide convincing evidence for the regional flow of high temperature fluids, similar to the Lower Carboniferous ore-forming fluids, within the Lower Palaeozoic metasedimentary basement. Systematic regional variations in homogenization temperature-salinity characteristics imply variable infiltration of local, low temperature, surface-derived fluids, consistent with a density driven convection model. In combination with existing isotopic data and thermal constraints, the new data strongly suggest that deep circulation of fluids was a fundamental process in the genesis of the Irish deposits. Therefore, purely topographically driven fluid flow models solely utilizing the Old Red Sandstone as a regional aquifer are inappropriate for the Irish orefield.
Two-dimensional modelling of stratigraphy and compaction-driven fluid flow in the Pannonian Basin
Authors: Van Balen R. T. , Lenkey L. , Horváth F. , Cloetingh S. A. P. L. 
Published: April 2008

Abstract
During the Pliocene-Quaternary time interval, the peripheral parts of the Pannonian Basin system have been uplifted and subsidence in the basin centre accelerated, causing a distinctive truncation pattern in the basin stratigraphy. Stress analyses indicate that the Pannonian Basin system, originally formed in an extensional regime, is subjected to a compressive stress since the early Pliocene. Results of forward modelling of basin subsidence and sedimentary filling along a cross-section through the southern part of the Pannonian Basin demonstrate that a change of the basin shape due to the compressive stress can successfully explain the observed pattern of differential uplift and subsidence occurring since the early Pliocene. In addition, the forward modelling of subsidence and fill provides constraints for the depth of lithospheric necking during extension, the palaeowater-depth history and lake-level changes in the southern part of the Pannonian Basin.
Compaction-driven fluid flow modelling shows that the first significant overpressures in the southern part of the Pannonian Basin developed during progradation of a large deltaic system, at a time when sedimentation rates increased rapidly. Due to the stress-induced acceleration of subsidence during Pliocene to Quaternary times, sedimentation rates increased again, causing a further increase of overpressure. The Pliocene stress induced uplift of the basin flanks combined with a preceding lake-level fall created a larger gravity potential of the groundwater table, enhancing the influx of meteoric water into the basin. This can explain observed diagenetic patterns in the southern part of the Pannonian Basin.
Ductile extension and the formation of the Aegean Sea
Authors: Jolivet L. , Patriat M. 
Published: April 2008

Abstract
The Aegean Sea and Tyrrhenian sea areas offer almost unique examples of actively collapsing orogens where the internal velocity field, kinematic boundary conditions and seismic activity can be compared and where older structures formed during the early stages of the same process are exhumed. We study these processes along two major transects. The first runs from Mt Olympos to the centre of the Cyclades, it is perpendicular to the direction of extension and offers the opportunity to study the brittle-ductile transition by direct observation of rocks and deformation. A gradient of finite exhumation along the transect has brought various crustal levels to the surface, and the localization of deformation during exhumation along major detachments has preserved older penetrative structures formed below. As these outcrops are distributed along the strike of a single crustal-scale tilted block the observed structures probably corresponds to a single tectonic event, and we can sample the associated deformation at increasing depth along the transect. We propose a stratification of deformation regimes associated to extension: localized normal faults in the brittle crust, distributed extensional shear bands with a partition between domains of noncoaxial and coaxial flow below 8–10 km, and distributed coaxial flow below 20 km. Flat-lying extensional shear bands extend brittle normal faults within the brittle-ductile transition. The second transect runs from Crete to Naxos and Mykonos and is parallel to the main direction of extension. It shows the transition from tectonic accretion and syn-orogenic extension near the subduction front to post-orogenic extension in the backarc region. The exhumation of metamorphic rocks proceeds in two stages: synorogenic ‘cold’ exhumation along detachments in the upper part of the accretionary complex, with a good preservation of HP-LT parageneses, and post-orogenic exhumation in a warmer environment in the backarc region with a complete retrogression of HP-LT parageneses. The 3D finite strain field is then compared to recent space geodesy data and the mechanism of crustal collapse discussed.
Tethyan sutures of northern Turkey
Authors: Okay Aral I. , Tüysüz Okan 
Published: April 2008

Abstract

The two main Tethyan sutures of Turkey, the İzmir-Ankara-Erzincan and the Intra-Pontide sutures, are reviewed through several well-studied transects crossing the suture regions. Both sutures have formed during the Early Tertiary continental collisions following northward subduction of Tethyan oceanic lithosphere. The İzmir-Ankara-Erzincan suture is represented along most of its
c.
2000 km length by Paleocene and younger thrust, which emplace the upper crustal rocks of the northern continent over that of the southern continent with an intervening tectonic layer of Cretaceous subduction-accretion complexes. These thrusts constitutes a profound stratigraphic, structural, magmatic and metamorphic break, of at least Carboniferous to Palaeocene age and form the main boundary between Laurasia and Gondwana in the Turkish transect. Voluminous subduction-accretion complexes of Triassic and Cretaceous ages occur respectively to the north and south of the suture giving the antithetic subduction polarities during these two periods. This, and evidence for a major accretionary orogeny of Late Triassic age north of the İzmir-Ankara-Erzincan suture suggest that two separate oceanic lithospheres, of Carboniferous to Triassic (Palaeo-Tethys) and of Triassic to Cretaceous ages (Neo-Tethys) respectively have been consumed along the suture. The final continental collision along the İzmir-Ankara-Erzincan suture was slightly diachronous and occurred in the earliest Palaeocene to the west and in the Late Palaeocene to the east. The
c.
800 km long Intra-Pontide suture is younger in age and have formed during the Early Eocene and younger continental collisions linked to the opening of the Western Black Sea Basin as an oceanic back-arc basin. At present the North Anatolian Fault, which came into existence in the Late Miocene, follows the course of the older Intra-Pontide suture.
Thermal conductivity of sedimentary rocks: uncertainties in measurement and modelling
Authors: Midttømme Kirsti , Roaldset Elen 
Published: April 2008

AbstractIn spite of the fact that thermal conductivity is a key factor in basin modelling, knowledge regarding the thermal conductivity of sedimentary rocks is scarce. In particular, hardly any information exists about claystones and mudstones which can make up 70–80% of a sedimentary basin. For the Upper Jurassic sediments of a section across the northern North Sea, basin modelling programs, using the geometric mean model, gave a deviation of 50°C for the present-day temperature, simply because the matrix conductivity was estimated by two different models. These uncertainties in the determination of thermal conductivities are partly due to problems in measuring, and partly to difficulties in modelling the thermal conductivity. Future work should concentrate on comparative studies and tests on all types of sedimentary rocks, directed towards improved measurement methods. This is of particular importance for clays, mudstones and shales, as measurements on these are associated with the greatest uncertainties. Standardized procedures that include detailed descriptions of sampling, sample preparation and measurement techniques are important to ensure that the thermal conductivity measured is unaffected by factors related to the measurement method. In thermal conductivity modelling it is our experience that the influence of sediment texture is underestimated by most models currently applied. Estimates based on the geometric mean model seem to be most reliable when the determination of matrix conductivity is restricted to the sediment type, mineralogy and texture of the sediments.