bluuebunny/crossref_metadata_2025_split huggingface dataset:
An integrated ichnological and sedimentological comparison of non-deltaic shoreface and subaqueous delta deposits in Permian reservoir units of Australia
Authors: Bann Kerrie L. , Fielding Christopher R. 
Published: April 2008

Abstract
Permian sequences in the Denison Trough of Queensland, eastern Australia, are productive conventional gas reservoirs. Previous attempts to interpret the reservoir bodies in terms of depositional environments have relied largely on sedimentary facies analysis and palynology. Sequences have been re-evaluated from a detailed, integrated ichnological and sedimentological perspective, resulting in a significant increase in the precision and resolution of the palaeoenvironmental interpretation. Various marine, coastal and upper delta plain deposits are recognized. Ichnological signatures have facilitated the differentiation of subaqueous delta deposits from those deposited in non-deltaic offshore and shoreface environments. Delta front facies are further subdivided by integrating ichnological and sedimentological data. Permian offshore and shoreface successions in the Denison Trough contain ichnological signatures that exhibit high diversities (25 ichnogenera comprising 32 ichnospecies), moderate to intense levels of bioturbation, uniformity of burrowing, and a wide variety of structures representing specialized feeding strategies. Examples from an additional reservoir dataset, the Tern Formation from the offshore Bonaparte Basin in north Western Australia, also clearly demonstrate the ichnological complexity of Permian shoreface successions. In contrast, Permian deltaic deposits contain ichnological signatures that reflect stressed environmental conditions. Assemblage diversity is reduced (16 ichnospecies), bioturbation intensity is significantly reduced, and uniformity of burrowing is sporadic.
The geology of north and central Malaita, Solomon Islands: the thickest and most accessible part of the world’s largest (Ontong Java) ocean plateau
Authors: Petterson Michael G. 
Published: April 2008

Abstract
This paper presents the most complete results yet published of geological surveys in Malaita, north of latitude 9°05′S between 1990 and 1995. The geology of Malaita reflects its position as an obducted part of the Alaska-size Ontong Java Plateau (OJP). The geology comprises a monolithological Cretaceous basalt basement sequence up to 3–4 km thick, termed the Malaita Volcanic Group (MVG), conformably overlain by a 1–2 km-thick Cretaceous-Pliocene pelagic sedimentary cover sequence. Cretaceous-Pliocene pelagic sedimentation was punctuated by alkaline basalt volcanism during the Eocene and by intrusion of alnöites during the Oligocene. Basement and cover sequences were both deformed by an intense, but short, middle Pliocene event. A number of localized, Upper Pliocene-Pleistocene, shallow-marine-subaerial, predominantly clastic formations overlie the middle Pliocene unconformity surface. The MVG comprises a monotonous sequence of pillowed and non-pillowed tholeiitic basalt lavas and sills with a predominant clinopyroxene-plagioclase-glass-opaques ± olivine mineralogy. The basaltic plateau morphology of the MVG is reflected in the presence of trap-like topographic features exposed in numerous river sections. Remarkably little sediment is present between basalt flows (most interlava contacts are basalt-basalt), indicating high to very high effusion rates. When present, inter-lava sediment is laminated pelagic chert or limestone, millimetres to centimetres thick, reflecting emplacement of the basalt in deep water (near or below the calcite compensation depth). Gabbro intrusions, dolerite dykes and an unusual spherulitic dolerite facies are locally present. The deep-water eruptive environment of the MVG probably was defined by the accumulation of voluminous eruptions from a multi-centred, submarine, possibly fissure-fed, volcanic source. The Malaitan cover sequence largely comprises a series of foraminifera-rich, pelagic calcilutites and calcisiltites with chert and, in the younger formations, arc-derived mudstone interbeds at various stratigraphic levels.
Partial melting below the Ontong Java Plateau
Authors: Herzberg Claude 
Published: April 2008

Abstract
Primary magma compositions for Kroenke-type basalts from the Ontong Java Plateau (OJP) have been estimated using a hybrid forward and universe model. For accumulated fractional melting of a fertile peridotite source, the primary magma had 16.8% MgO and lost 18% olivine by fractional crystallization to produce Kroenke-type basalts; the melt fraction was 0.27 and the potential temperature was 1500°C. For equilibrium melting of a fertile peridotite source, the primary magma had 19.3% MgO and lost 25% olivine by fractional crystallization to produce Kroenke-type basalts; the melt fraction was 0.30 and the potential temperature was 1560°C. The model peridotite source composition, melt fraction and potential temperature required to produce the primary OJP magmas are in excellent agreement with those that have been independently estimated from incompatible trace-element concentrations.
Phreatomagmatic eruptions on the Ontong Java Plateau: chemical and isotopic relationship to Ontong Java Plateau basalts
Authors: White Rosalind V. , Castillo Paterno R. , Neal Clive R. , Fitton J. Godfrey , Godard Marguerite 
Published: April 2008

Abstract
The compositions of glass clasts in volcaniclastic rocks recovered from drilling at Site 1184 on the eastern salient of the Ontong Java Plateau (OJP) are investigated using microbeam analytical methods for major, minor and trace elements. These data are compared with whole-rock elemental and isotopic data for bulk tuff samples, and with data from basalts on the high plateau of the OJP. Three subunits of Hole 1184A contain blocky glass clasts, thought to represent the juvenile magmatic component of the phreatomagmatic eruptions that generated the volcaniclastic rocks. The glass clasts have unaltered centres, and are all basaltic low-K tholeiites, with flat chondrite-normalized rare earth element (REE) patterns. Their elemental compositions are very similar to the Kwaimbaita-type and Kroenke-type basalts sampled on the high plateau. Each subunit has a distinct glass composition and there is no intermixing of glass compositions between subunits, indicating that each subunit is the result of one eruptive phase, and that the volcaniclastic sequence has not experienced reworking. The relative heterogeneity preserved at Site 1184 contrasts with the uniformity of compositions recovered from individual sites on the high plateau, and suggests that the eastern salient of the OJP had a different type of magma plumbing system. Our data support the hypothesis that the voluminous subaerially erupted volcaniclastic rocks at Site 1184 belong to the same magmatic event as the construction of the main Ontong Java Plateau. Thus, the OJP would have been responsible for volatile fluxes into the atmosphere in addition to chemical fluxes into the oceans, and these factors may have influenced the contemporaneous oceanic anoxic event.
Predicting fracture swarms — the influence of subcritical crack growth and the crack-tip process zone on joint spacing in rock
Authors: Olson Jon E. 
Published: April 2008

Abstract

Swarms or clusters represent an exception to the widely accepted idea that fracture spacing in sedimentary rock should be proportional to mechanical layer thickness. Experimental studies and static stress analysis do not provide adequate explanation for fracture swarm occurrence. The problem is re-examined numerically, accounting for the dynamics of pattern development for large populations of layer-confined fractures. Two crucial aspects of this model are: (1) the inclusion of three-dimensional effects in calculating mechanical interaction between simultaneously propagting fractures; and (2) the use of a subcritical crack-propagation rule, where propagation velocity during stable growth scales with the crack-tip stress intensity factor. Three regimes of fracture spacing are identified according to the magnitude of the subcritical index of the fracturing material. For low subcritical index material (
n
= 5) numerous fractures propagate simultaneously throughout a body resulting in irregular spacing that is, on average, much less than layer thickness. For intermediate subcritical index (
n
= 20) one fracture propagates at a time, fully developing its stress shadow and resulting in a pattern with regular spacing proportional to layer thickness. For high subcritical index cases (
n
= 80) fractures propagate in a fashion analogous to a process zone, leaving a fracture pattern consisting of widely spaced fracture clusters.
The relationship of tilt and twist of fringe cracks in granite plutons
Authors: Bankwitz P. , Bankwitz E. 
Published: April 2008

Abstract

Joint fractography in European plutons frequently shows large fringe-tilt angles connected to small fringe-crack twist angles (type A). In contrast to this first type, fringes of joints that tilt at small angles out of the parent joint plane are often associated with high twist angles of en echelon fringe cracks (type B). The interaction of tilt and twist angles gives evidence for the mode (I, II and III) acting at the advancing crack front during fracture propagation and the formation of fringes. The different fringe types depend on the varying influence of mode II or mode III, which establishes the degree of tilt or twist, in addition to opening-mode I that governs the crack propagation. Fringe types A and B are not randomly distributed. Within several plutons the first joints are characterized by a frequency of type A, and in other plutons by the dominance of type B. A third group of plutons is characterized by low tilt and low angle of twist for early joint fringes. The range of tilt/twist ratios of the earliest joints decreases with increasing depth of pluton emplacement and joint formation. The trend of the ratio approaches a value of between 0.5 and 1.0 at greater depth (
c.
15 km). The ratio seems to be suitable for a prognosis of the possible depth of first joint formation.
Differences between veins and joints using the example of the Jurassic limestones of Somerset
Authors: Peacock D. C. P. 
Published: April 2008

Abstract
Although veins and joints are both extension fractures, they should be treated separately, especially in field analyses. For example, they commonly form at different times and under different conditions. Excellent exposures of the Liassic limestones at Kilve, Somerset, UK, are used as a case study. These rocks show calcite veins related to the Mesozoic extension and Alpine contraction of the Bristol Channel Basin, and joints that appear to have been caused by late- or post-Alpine stress release. The veins at Kilve show the following characteristics that distinguish them from joints. (1) They are mineralized. (2) Veins have measurable widths (up to tens of millimetres wide) and represent measurable strain. En echelon veins are common at Kilve, and indicate shear strains. (3) Vein widths may obey a power-law scaling relationship. (4) The veins were open for long enough and under the correct conditions for calcite to be deposited, indicating high fluid pressures. They are also typically en echelon. (5) Veins form sets with a narrow range of strikes, whereas the joints typically form complex networks. (6) The veins at Kilve are commonly clustered around faults, and are precursors to, or synchronous with, the faults.
Indentation pits: a product of incipient slip on joints with a mesotopography
Authors: Engelder Terry , Schulmann Karel , Lexa Ondrej 
Published: April 2008

Abstract
The mechanism for structural damage during incipient slip on joints within the Melechov Granite, Czech Republic, changes with the misalignment of the joint’s mesotopography, largely a plumose surface morphology. Prior to slip, the joint surfaces are well mated so that contact area is organized on a microscopic scale. During the first phase of slip, diffusion-mass transfer is the active deformation mechanism between the sliding surfaces of the joints, as indicated by the extensive growth of crystal-fibre lineations characteristic of slickenside surfaces. After slip of the order of 1 cm or more, the mesotopography becomes mismatched and the contact area is reorganized to form indentation pits aligned on the ridges of hackle plumes. Indentation pits, that are testimony to a brittle process, are generated by the excavation of Hertzian ring cracks that propagate under contact loading of a brittle substrate. The depth of the indentation pits increases with contact width, suggesting that indentation creep is active. Following indentation along Hertzian ring cracks the slip mechanism transforms to a frictional abrasion. The distribution of indentation track lengths is consistent with laboratory wear grooves generated during earthquake-like stick-slip sliding. The elliptical shape of the indentation pits indicates a gradual decrease in contact area, a process that is consistent with a slip-weakening mechanism during a stick-slip cycle.
Geophysical techniques for forensic investigation
Authors: Fenning Peter J. , Donnelly Laurance J. 
Published: April 2008

Abstract
A wide range of geophysical techniques is applied in forensic investigations where the target objects are frequently buried under ground and are often small in size. These include targets which are only a few centimetres in diameter but located within a large search area are often of several hectares. The application of a specific geophysical technique may be governed by the physical properties of the target object and its local surroundings. However, operational and financial costs are important. Topographical and geological variations or presence of man-made structures may hinder the application of the most cost-effective technique. Additionally, site area, logistics and weather conditions are also important factors.
Generally, to overcome these difficulties it is recommended that forensic geophysics be carried out along conventional geophysical guidelines as used in civil-engineering site investigation. On occasion, departure from these conventional guidelines may be beneficial in that field survey data acquisition can be complemented by simultaneous direct invasive assessment of geophysical anomalies instead of waiting until office reporting has been completed. Three case studies are presented: one relates to a search for a buried metal target located using a scanning magnetometer with simultaneous excavation, and two relate to searches for graves and buried wooden coffins
The importance of stratigraphy in forensic investigation
Authors: Hanson Ian D. 
Published: April 2008

Abstract
The laws of stratigraphy, developed in geology, have long been adopted for archaeological use. Archaeological excavation in the UK relies on the application of these principles to define, interpret and understand site history. The adaptation of archaeological methods to forensic settings has recently resulted in successful analysis of stratigraphy-defining complex series of events on murder burial scenes. The breadth of physical evidence that can be recovered through stratigraphic excavation is great, and that which can be lost without due attention to the buried surfaces forming an intrinsic part of the stratified deposits of a site is significant. Recent case examples demonstrate the importance of employing stratigraphical principles in the excavation and interpretation of buried cultural and natural deposits as part of multidisciplinary forensic investigation.
Development of a coastal dune sediment database for England and Wales: forensic applications
Authors: Saye Samantha E. , Pye Kenneth 
Published: April 2008

Abstract

A database of coastal dune sediments in England and Wales has been developed with potential applications in forensic investigations. Coastal dunes are popular sites for criminal-related activities, including burial of drugs, weapons and murder victims. The coastal dunes and associated areas of windblown sand in England and Wales occupy an area of approximately 200 km
2
within 112 individual identified systems. Research has been undertaken to ascertain the spatial variation in sedimentological properties of the coastal dune sediments in England and Wales. Field sediment sampling has been undertaken at each dune system. More than 1500 sediment samples have been analysed by laser diffraction to determine particle size characteristics, and more than 500 have been analysed by inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine chemical composition. Two examples illustrate how the database has been used in criminal investigation.
‘Unique’ particles in soil evidence
Authors: Sugita R. , Marumo Y. 
Published: April 2008

Abstract
Soil is presented as evidence as a mixture of both natural and artificial materials. ‘Unique’ particles found in soil may provide useful information to indicate the origin of the soil and, when found in soil evidence, may provide rapid discrimination between samples. Evidence in poor condition may also be examined for these diagnostic particles. This paper describes some case examples and research, involving geological particles, plant fragments and algae, in which microscopy played an important role.
Forensic examination of rocks, sediments, soils and dusts using scanning electron microscopy and X-ray chemical microanalysis
Authors: Pye Kenneth 
Published: April 2008

Abstract
Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) microanalysis are powerful techniques for forensic and wider environmental analysis of a range of materials, including rocks, sediments, soils and dusts. Methods of analysis have evolved rapidly over the past 40 years and computer-controlled, variable pressure SEMs with integrated EDX now provide the opportunity for rapid, automated analysis of large numbers of samples and particulates within individual samples. However, interpretation of the data requires care and experience on the part of the operator, and samples should always be checked by visual inspection. Early SEM work on rocks and sediments mainly used the secondary electron (SE) mode to produce topographical contrast on rough surfaces, but more recent studies have utilized the capacity of backscattered electron (BSE) imaging to image both topographical and atomic number contrast. BSE microscopy, combined with X-ray mapping, provides a rapid means of locating unusual particles and grain coatings, and of mapping their distribution, which may be of diagnostic or discriminatory importance. In the past, much attention has been given to grain surface textural features (mainly of quartz) but many such studies have suffered from a high degree of subjectivity, poor reproducibility, lack of discriminatory power, and high cost both in terms of time and money. The application of digital imaging and statistical data-processing techniques can to some extent reduce these problems but, in general, chemical characterization of particles offers a more powerful approach. This paper provides an overview of these techniques, discusses their limitations and illustrates some of the forensic and wider environmental applications.
The archaeologist as a detective: scientific techniques and the investigation of past societies
Authors: Henderson Julian 
Published: April 2008

Abstract

The use of scientific techniques in the investigation of archaeological sites and artefacts has a long history. These days archaeological science as a discipline has matured to the extent that well-defined questions can be answered in increasingly refined ways. In this paper consideration of specific case studies highlights the kinds of investigations that have been carried out on archaeological materials. The research projects are described in ways that show parallel approaches to more recent types of research in police forensic work. The two case studies focused on are: (1) Islamic glass production — a cross-roads in technology? (eighth to twelfth centuries
ad
); (2) Ottoman Iznik pottery: the state of the art or the art of the State? (fifteenth to seventeenth centuries
ad
). A range of analytical techniques has been used, including electron microprobe analysis, inductively coupled plasma atomic emission spectrometry, scanning electron microscopy and mass spectrometry. Clearly these techniques provide different (and sometimes overlapping) information which help to answer research questions. The characterization of raw materials, production processes and distribution zones of the products all form part of a holistic approach. Ideally the results should be embedded in our knowledge of past societies, just as the interpretation of police forensic work should be.
Comparison of soils and sediments using major and trace element data
Authors: Pye Kenneth , Blott Simon J. 
Published: April 2008

Abstract
Analysis of geochemical data has become an important tool used in forensic comparisons of soils and sediments. The combined use of inductively coupled plasma optical emission spectrometry and mass spectrometry (ICP-OES and ICP-MS) instrumentation allows the abundance of up to 50 elements to be routinely determined in small samples (typically >0.1g). However, key issues concern the extent to which analysed subsamples are representative of the parent material from which they are taken, the best means of comparing datasets for different samples, and interpretation of the significance of the results obtained. ICP measurement precision for most elements is good, but it is important to understand the degree of variation that can arise due to subsampling procedures and selective transfer mechanisms relating to forensic exhibits, as well as the extent of spatial (and sometimes temporal) variability which exists in nature. Although analysis of several different size fractions is often helpful where sufficiently large samples are available, analysis of a standardized <150μm fraction separated from a bulk sample in many cases provides adequate discrimination between samples and provides the most practical method for mass-screening of samples. Where possible, duplicate or triplicate sample preparations should be made, and several analytical determinations made on each prepared subsample. However, the additional time, cost and sample size requirements involved need to be weighed against the benefits of undertaking additional types of analysis of the samples. In order to obtain maximum information from multielement geochemical data, the dataset should be evaluated using a variety of numerical, statistical and graphical procedures. This paper discusses a number of options for such data evaluation using a simple dataset example. Casework experience and experiments have shown that, even in complex situations, multi-element geochemical data can provide very sensitive environmental indicators. However, such data should normally be used in combination with the results of other analyses when making forensic comparisons of soils and sediments.