bluuebunny/crossref_metadata_2025_split huggingface dataset:
Latest Cretaceous mollusc species ‘fabric’ of the US Atlantic and Gulf Coastal Plain: a baseline for measuring biotic recovery
Authors: Koch Carl F. 
Published: April 2008

Abstract
Studies of biosphere changes with time risk serious misinterpretation if they are based on a single section or closely spaced sections because lateral geographical changes in a fauna’s distribution can be interpreted erroneously as profound temporal change. This problem can be ameliorated if the variation in fauna geographical distribution is well documented because such information would provide a reference to which temporal changes may be compared. That is, if temporal changes are greater than documented lateral changes, extinction or origination may have occurred. If temporal changes are within the observed lateral changes, then no compelling need to suggest evolutionary change exists.

Data for the
Haustator bilira
Assemblage Zone in the Atlantic and Gulf Coastal Plain are given in terms of nine areas distributed along a 2100 mile outcrop belt. The data result from examination of over 110 000 larger invertebrate fossil specimens, most of which are mollusc. Each mollusc species encountered was classified by feeding types, habitat and size. Because the
Haustator bilira
Assemblage Zone represents the youngest Cretaceous sediments of the Coastal Plain, the data assembled provide a reference plane just prior to the K/T boundary. It is hoped that these data will be used to evaluate the significance of biosphere changes in the vicinity of the K/T boundary.
Scaling of fault displacements and implications for the estimation of sub-seismic strain
Authors: Pickering G. , Bull J. M. , Sanderson D. J. 
Published: April 2008

Abstract

Fault displacement populations have been shown to follow a power-law scaling relationship characterized by an exponent D. This relationship can be used to make predictions of the sub-seismic fault population from data derived from seismic surveys. Although fault populations exist in three dimensions the use of section data is recommended.
D
-values derived from sections can be applied directly to several problems, and are also related to the
D
-value for the fault set in higher dimensions. Accurate determination of
D
requires proper consideration of the scale range and sample size limitations of available data. The most common technique of using a cumulative frequency graph often leads to an upwards bias. An iterative correction procedure is proposed. Discrete frequency methods avoid this bias, but as a standard linear interval graph has other associated problems, a log-interval graph method is preferred. Simulations of these methods, applied to random computer generated samples from power-law distributions, have been made to examine the accuracy of D-values derived from typical data. Equations to estimate the confidence intervals for these D-values have been derived from a synthesis of the results. The application of the techniques is shown using fault data measured on seismic sections from the Southern North Sea and the Inner Moray Firth. Where local differences in D are shown to be significant, there is usually a marked change in structural style. Fault data are used to make improved estimates of crustal extension (β) by extrapolating the derived power-law relationship. A value of β = 1.20 is calculated for the Inner Moray Firth. Applications predicting the intersection of horizontal wells with ‘large’ sub-seismic faults and quality control of fault interpretation on seismic sections are also described.
Ductile strain effects in the analysis of seismic interpretations of normal fault systems
Authors: Walsh J. J. , Watterson J. , Childs C. , Nicol A. 
Published: April 2008

Abstract
The limited vertical resolution of reflection seismic data results in sub-resolution structures accommodating appreciable ductile strains which should be taken into account in structural restoration and balancing and in analysis of fault displacements. Non-ductile strains are expressed as discontinuities, such as fault offsets. A fault map of an intensively mined coal-seam is used to demonstrate the role of structures which would not be detected by a typical offshore seismic survey. Four examples are given of interpretations of seismic datasets in which significant ductile strain can be demonstrated; (i) an array of normal faults in which significant extension is accommodated by sub-seismic faults, (ii) a relay zone in which ductile shear strain accommodates significant displacement and change of bed-lengths, (iii) an intersection zone between conjugate normal faults which is effectively a zone of ductile pure shear strain with horizontal extension, and (iv) a hanging-wall fold which accommodates appreciable ductile displacement and ductile bed extension. In all these cases the ductile strains and displacements can be estimated from the seismic interpretation. Unless ductile strains are incorporated in restorations bed lengths will not balance. Balancing nevertheless remains the prime method for detection of grossly invalid sections.
The application of cross-section construction and validation within exploration and production: a discussion
Authors: Buchanan James G. 
Published: April 2008

Abstract
Numerous published studies have shown that cross-section balancing and validation techniques are a powerful method of structural analysis. This paper outlines reasons why cross-section validation also is a valuable methodology within the oil/gas industry.
Cross-section validation is a vehicle of getting analytical rigour into seismic and non-seismic interpretation by testing the section against the rules of structural geology (in particular geometry).
In addition to the analysis of structural traps, cross-section validation can be used in oil or gas sourcing studies, especially in the relative timing of hydrocarbon migration and trap formation/destruction. It is therefore a valuable methodology in both 3D basin analysis and prospect risking/ranking.
Cross-section validation should be an integral part of the petroleum geologist’s tool kit to aid further understanding of the 3D evolution of a basin and basin fluids through time. This technique, when used with other methodologies, such as sequence stratigraphy and basin modelling, allows the interpreter to use all the available data sets to constrain geological models on hydrocarbon prospectivity.
Construction and validation of extensional cross sections using lost area and strain, with application to the Rhine Graben
Authors: Groshong Richard H. 
Published: April 2008

Abstract
The simultaneous area balance of multiple horizons in a graben system formed above a detachment is the basis for the lost-area section construction and validation technique. Area balance requires that the area displaced below the original regional level of each bed in a graben (the lost area) be balanced by the displaced area at the boundary of the system, given by the product of the displacement times the depth to detachment. For multiple horizons, this relationship is a straight line on a plot of lost area versus depth. The slope of the line is the displacement and the depth intercept is the depth of the detachment. In general, beds within the graben system undergo both visible and homogeneous layer-parallel extension. The homogeneous component can be calculated from the width of the graben system, the lost area, and the depth to detachment. Conversely, the detachment depth may be calculated from the total layer-parallel extension and the lost area. The technique is illustrated by application to the Rhine graben. The Rhine graben is inferred to have formed with its detachment at the base of a normal thickness (31 km) of crust and to have been uplifted. Crustal necking with a detachment at 15 km depth is a viable alternative but requires three times the layer-parallel extension of 6.3% measured at the top of the Permian and older basement. The large difference between the layer-parallel extension (6.3%) and the crustal extension (29%) is in close agreement with an area-balanced full-graben model having boundaries that slope at 60° toward the centrer of the graben.
Forward modelling of compaction above normal faults: an example from the Sirte Basin, Libya
Authors: Skuce A. G. 
Published: April 2008

Abstract
Seismic data reveal the structure of a large normal fault that forms the western boundary of the Agedabia Trough in the central Sirte Basin, Libya. A significant monoclinal flexure in the sediments forming the hanging wall of this fault is interpreted to have been generated by their compaction. A computer forward model supports this interpretation. Characteristics of this kind of structure are a vertical synclincal axial plane above the hanging-wall cutoff of the basement and an inclined but less distinct anticlinal axial plane above the footwall cutoff of the basement. Dips increase with depth. The model also shows how compaction can cause sedimentary growth within the hanging wall rather than just at the fault plane. In some circumstances, compaction can produce anticlinal structures in normal fault hanging walls that could easily be confused with inversion structures. Structures can be produced by compaction in normal fault hanging walls even where no lithology contrast occurs across the fault. Compaction structures generally will be most obvious over large planar faults that involve basement. Nevertheless, compaction structures are also important in the case of detached listric faults: in this case the effects are often obscured by the superimposition of fault bend folds that will have similar or greater magnitudes but are typically anticlinal, whereas the compaction structures are usually synclinal. Compaction effects compound the difficulties of geometric inverse modelling.
Kinematic modelling of normal fault geometries using inverse theory
Authors: Kerr Hugh G. , White Nicky 
Published: April 2008

Abstract
The principal features of a general kinematic method which uses the shapes of deformed strata to calculate normal fault geometries at depth in two and three dimensions are summarized here. This method assumes that hanging-wall deformation can be represented by arbitrarily inclined bulk simple shear and it should be applicable to faults at any scale. In two-dimensional modelling, deformation is assumed to occur within the plane of section. Deformation in three dimensions is parameterized by the three Euler angles which describe the horizontal component of the slip vector, the rake (i.e. pitch) angle and the inclination of shear planes. Differential compaction is included in both cases. Since we use inverse theory to determine fault geometries, the quality of our solutions is easily investigated. Both two- and three-dimensional algorithms have been rigorously tested on synthetic data, on sand-box experiments, and on depth-converted and interpreted seismic reflection profiles. Modifications of this approach can be used to calculate fault geometries which have changed shape during or after fault displacement. A similar approach is applicable to reverse faulting.
Multiple detachment levels in thrust tectonics: Sandbox experiments and palinspastic reconstruction
Authors: Verschuren Mark , Nieuwland Dick , Gast Jim 
Published: April 2008

Abstract
Sandbox models of thrust tectonics with multiple detachment levels allow alternative interpretations of fault patterns and evolution, even though they are well controlled experiments. Palinspastic reconstruction resolves these ambiguities and leads to refined interpretations. It reveals that if there are thick viscous interlayers, all non-fault related contraction can be accommodated by folding, without tectonic compaction. It also confirms the complete decoupling of faulting above and below a thick weak viscous layer, and the initial straightness and regular spacing and dips of thrusts above a decollement of low basal friction. A weak elasto-plastic interlayer or decollement merely has a lubricating effect, without complete decoupling.
Many natural thrust systems are underlain by a ductile substratum and have more than one decollement level. These examples almost always exhibit a complex thrust belt geometry and are apparently formed by different thrusting events that can be difficult to interpret and to time relative to one another.
Weak decollement materials and interlayers have a strong effect on the structural style of thrust belts at the moment of detachment. However, other material properties, in particular the viscosity, play a dominant role during the structural development following detachment (the overthrust phase).

The objective of this study was to improve structural interpretation of data from areas of thin-skinned thrust tectonics with weak ductile detachment horizons (i.e. excluding large scale basement involvement). The approach involved:

•
the use of sandbox experiments to provide controlled structural models with different decollement rheologies, and

•
the refinement and validation of selected cross-section interpretations with palinspastic reconstruction.

The result is a set of better constraints on structural interpretation of cross-sections in thrust tectonics. In natural cases, the most common weak decollement lithologies are over-pressured shales and evaporites, in particular rock salt. In our experiments we have simulated rock salt by using silicone putty (‘SP’), a viscous material that can flow slowly as a Newtonian fluid. We modelled overpressured and/or very soft clay with an oil-water emulsion (‘OWE’), which is a ductile, weak elasto-plastic, non-viscous material in which localized shear zones can form, as in any other elasto-plastic solid.
Kinematics within the Kłodawa salt diapir, central Poland
Authors: Burliga Stanisław 
Published: April 2008

Abstract
The Kłodawa salt diapir consists of deformed Zechstein rock salts, with subordinate anhydrite, dolomite and shales. Upward movement of these rocks and the structural evolution of the diapir started in the Triassic and continued at least until the Tertiary. Lithological, and thus rheological variation resulted in the development of a variety of tectonic structures on different scales, which can be observed in mine galleries intersecting the diapir at several levels. The rocks are folded, faulted, fractured and boudinaged, and their behaviour is strictly related to the competence contrasts between layers of different lithology. There is a range of competence from dolomite through anhydrite, shale, clayey salt and rock salt, to the least competent, potassium salt. Kinematic indications at level 600 are provided by boudins, book-shelf structures, asymmetric folds, small-scale faults, tension gashes and veins. These were produced during different stages in the evolution of the diapir and provide evidence for various mechanisms of deformation, ranging from ductile flow to brittle fracturing. The small-scale structures allow the visualization and identification of larger folds and the depiction of their development. They record changes of shear directions along the fold limbs, and also indicate a change in folding mechanism from flexuralslip folding to shear folding. High strain is localized in bedding-parallel zones and within areas dominated by low competence rocks. These zones usually form discrete horizons separating domains of more competent rocks, which show little evidence of deformation and, occasionally, undeformed synsedimentary structures (dessication polygons). The displacements were zonal, accommodated by low competence rocks, with more competent rocks passively transported as rafts within the former. The zones of intense transport are localized within beds of rock salt and potassium salt.
Deformation and sedimentation around active Miocene salt diapirs on the Tihama Plain, northwest Yemen
Authors: Davison Ian , Bosence Dan , Alsop G. Ian , Al-Aawah Mohammed H. 
Published: April 2008

Abstract

The Al Salif and Jabal al Milh salt diapirs of Miocene age cut through a 4–5 km thick overburden of Miocene to Recent sedimentary rocks in the southern Red Sea. The Al Salif diapir is part of a north-south oriented diapiric wall which has caused updoming of the overburden and active extensional faulting. The halite is folded into tight to isoclinal subvertical folds, with largescale rafts of interbedded gypsum-anhydrite boudinaged on the fold limbs. There is no evidence for large-scale overburden stoping or injection of salt into overlying faults and fractures, and the upward movement of the salt dome is probably caused by the overburden being forced aside and sliding off the dome. The upper surface of the salt is an undulating smooth surface which was exposed at the sea-floor during the Quaternary. Coral reefs with
14
C ages of 3700 a have been raised up to an elevation of 17 m above present-day sea-level, giving a surface uplift rate of 4.6 mm a
−1
. At the Jabal Al Milh diapir, recumbent folding and thrusting are the main deformation features observed in the siltstones and gypsum layers of the overburden. The overburden has been rotated to the vertical at least 200 m from the diapir walls. The folding and thrusting is interpreted to be caused by overflow of salt in a namakier. This study shows that overburden sediments above the Al Salif diapir extended to allow sediments to slide from the salt dome crest by listric faulting, whereas sediments underlying the Jabal al Milh salt glacier were sheared and shortened in the horizontal direction.
Uplift rate relative to base-levels of a salt diapir (Dead Sea Basin, Israel) as indicated by cave levels
Authors: Frumkin Amos 
Published: April 2008

Abstract

Rapid downcutting rates in the extremely soluble salt of the Sedom diapir, Dead Sea basin, Israel, allow cave channels to become rapidly graded with respect to base level. Diapir uplift leaves the older passages high and dry above present base level. Dating these passages by
14
C allows us to estimate diapir uplift rates, taking into account previous Dead Sea levels. Maximum mean Holocene uplift rates are 6–7 mm a
−1
along the eastern fault of Mount Sedom.
Hydration diapirism: a climate-related initiation of evaporite mounds in two continental Neogene basins of central Spain
Authors: Hoyos Manuel , Doblas Miguel , Sánchez-Moral Sergio , Cañaveras Juan Carlos , Ordoñez Salvador , Sesé Carmen , Sanz Enrique , Mahecha Vicente 
Published: April 2008

Abstract
While many halokinetic models consider that a thick overburden is necessary before diapirism develops, other studies show that salt might begin to move soon after deposition in response to different factors (e.g. regional extension). We describe two continental Neogene basins in central Spain, characterized by three Miocene sedimentary units, where unusually early initiation of evaporite mounds or ‘incipient pillows’ occurs, with no overburden on top of them. The arguments suggesting the early bulging of the evaporites of the Lower Unit, forming a palaeorelief before and during the deposition of the Intermediate Unit, rely on certain characteristics of the palaeokarsts developed on the roof of the Lower Unit, as well as in the nature, disposition, thickness, and synsedimentary processes of the Intermediate Unit. Folds, faults, tension gashes, and collapse structures develop within the evaporite mounds, and these deformation features might be related to their uplift history. The agent of initiation suggested in this paper for the evaporite mounds ‘hydration diapirism’, or a volume increase related to the hydration of anhydrite to gypsum has not been previously recognized in the literature. A series of sedimentological and palaeontological arguments further suggest that this chemical reaction was triggered by a climatic change at the boundary between the Lower and the Intermediate Units.
Deformation in the late Permian Boulby Halite (EZ3Na) in Teesside, NE England
Authors: Smith Denys B. 
Published: April 2008

Abstract
Differential (mainly lateral) movement of up to a few hundred metres is interpreted from borehole data to have taken place in the late Permian Boulby Halite in Teesside, northeast England, probably when it was buried to a depth of 2000 m or more. This interpretation is based on a marked variation in the present thickness of the formation, which is thought to have been almost uniformly thick when formed, together with evidence from more than 20 borehole cores of contortion, fracturing, flow-lineation and flow-brecciation; evidence of bedding-plane slip was noted in one core. Inferred boudinage in the lower part of the formation is interpreted as evidence of local extension. Unusually for rock-salt, faults cut halite in eight of the cores, and voids in fractures and faults were noted in halite in six cores.
Salt tectonism in the Persian Gulf Basin
Authors: Edgell H. S. 
Published: April 2008

Abstract
The Persian Gulf Basin is an elongate, margin sag-interior sag, sedimentary basin spanning the last 650 Ma along the northeastern subducting margin of the Arabian Plate and is the largest basin with active salt tectonism in the world. This basin is asymmetrical in NE-SW cross section with sediments thickening from 4,500 m near the Arabian Shield to 18,000 m beside the Main Zagros Reverse Fault. Halokinesis in the Persian Gulf Basin originates where major intersecting basement faults cut the buoyant salt beds of the Neoproterozoic Hormuz Series (1.5 to 2.5 km thick) and the equivalent Ara Formation of Oman where salt thickness reaches 4 km. Another source of salt is the Oligo-Miocene Gachsaran Formation, forming Lali salt plug. Major basement fault trends control salt tectonism in the basin, namely the extensional N-S Arabian Trend, the sinistral NE-SW Aulitic Trend, the dextral Erythaean Trend and the extensional E-W Tethyan Trend. The main types of salt structures in the Persian Gulf Basin are salt domes, salt pillows, salt walls, salt piercements, rim anticlines, turtleback structures, disharmonic folds, orogenic fold fillings and dissolution drapes. Diapiric oil fields, account for 60% of the 600 billion barrels of recoverable oil reserves of the Persian Gulf Basin and have grown continuously since Late Jurassic, or since Permian in some large structures, such as Bahrain.