bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple faults in ductile simple shear: analogue models of flanking structure systems
Authors: Exner Ulrike , Grasemann Bernhard , Mancktelow Neil S. 
Published: April 2008

Abstract
Rotational behaviour and deformation around multiple faults was investigated in analogue experiments using a linear viscous matrix material under simple shear boundary conditions. Previous analogue and numerical studies have shown that, for single faults, characteristic deformation geometries are produced in initially straight marker lines parallel to the shear zone boundary (flanking structures). Observations from several natural shear zones suggest that not only single faults, but often several parallel or conjugate fault planes are subjected to progressive shear resulting in distinctive deflection geometries. If the distance between faults is on the order of their length, or less, then the perturbation flow fields interfere and coalescence, and finite deflection structures develop that are distinctly different from those around single fractures. In particular, coeval contractional and extensional geometries may develop across conjugate faults, although for bulk simple shear the total length of marker lines parallel to the shear zone boundary cannot change. This advises caution in inferring shear-zone parallel contraction or extension from secondary slip surfaces. In contrast to single flanking structures, conjugate flanking structure systems occurring in natural shear zones are reliable shear sense indicators due to their triclinic symmetry.
The deliberate search for stratigraphic and subtle combination traps: where are we now?
Authors: Allan J. R. , Sun S. Q. , Trice R. 
Published: April 2008

Abstract
Stratigraphic and subtle combination traps have a well-documented track record as significant producing hydrocarbon resources. The majority of these success cases come from onshore USA where unprecedented drilling densities combined with a long history of hydrocarbon exploration provide a large portfolio of stratigraphic and subtle combination traps. By comparing USA-based examples with other global cases it is evident that numerous basins still have the potential for exploration success associated with these traps. This paper attempts to raise the awareness of the exploration potential of stratigraphic and subtle combination traps through four approaches. Firstly, a summary of key global statistics related to stratigraphic and subtle combination traps is provided with the intention of demonstrating that they have historically represented a key hydrocarbon resource. Secondly, a classification scheme is introduced and acts as a reference for the observations and case studies presented. The third component of this paper is to present a range of case studies, which serve to demonstrate the exploration history behind successful discoveries associated with stratigraphic and subtle combination traps. The final component is to consider the general exploration history and from this long experience highlight the key techniques necessary for the development of a successful exploration strategy.
Identification of stratigraphic traps with subtle seismic amplitude effects in Miocene channel/levee sand systems, NE Gulf of Mexico
Authors: Godo Theodore J. 
Published: April 2008

Abstract
Stratigraphic traps created and preserved on the unconfined slope of the ancestral Mississippi submarine fan in the northeastern Gulf of Mexico have been found to contain substantial and profitable hydrocarbon reserves. Nearly 2 trillion cubic feet of gas (350 million barrels of oil equivalent) have been produced in the last 13 years in less than 1400 feet (425 m) of water. Drilling results have yielded 31 fields from 45 drilled prospects for a success rate of 69%. The main phase of exploration lasted eight years. The first 3D survey in 1994 sparked a major increase in drilling and success rates until the last field was discovered in 2001. This play has now essentially been exhausted of sizeable opportunities.
The underlying Mesozoic section sources hydrocarbons to the play for middle Miocene slope sands. The unconfined (non mini-basin) slope sands are turbidites and debris flows that were deposited between 5 and 25 miles (8 and 40 km) from their coeval shelf margins. Stratigraphic traps in this environment are created at the margins of the levees as they interfinger with slope shales. Additional geometric modifications of the stratigraphic traps result from post-depositional erosion or ‘cannibalization’. The erosion left ‘monadnocks’, or remnant patches of porous sands, that are encased in low permeability shales. Turbidite channel/levee deposits are the dominant reservoir facies in these ‘patches’; however, they may consist of channel, levee, or debris flow facies. Detailed mapping of these dominantly gas charged erosional remnants shows little to no fit of seismic amplitude effects to structure and the hydrocarbon accumulations often appear as amplitude anomalies ‘floating in space’.
This work was done to provide an analogue study, as well as to document any remaining prospects that were initially overlooked. Almost every discovery and dry hole in the trend was interpreted and included in this study. Integrating the well control into the geological model by using detailed seismic stratigraphy, whole core description, dipmeter logs, seismic to well tie synthetics, Gassmann fluid substitution and AvO analysis, provided the necessary insight to prosecute this play.
Within the play area, seismic velocities of sands and shales are very similar. As a consequence of this, seismic reflections are generally weak and, due to the stratigraphic variability, they are discontinuous. Hence, standard sequence stratigraphic mapping techniques alone are not enough to define these subtle traps. The key to successful exploration is a complete understanding of the rock properties. All of the fields examined displayed subtle amplitude anomalies associated with the presence of hydrocarbons. The ability to understand and quantify both the amplitude is essential to increasing the probability of success in this play.
The geological exploration techniques applied by BG in evaluation of the Buzzard Field prior to discovery
Authors: Moore Richard M. , Blight Richard D. 
Published: April 2008

Abstract

Substantial technical studies were undertaken by BG in the exploration effort which preceded the discovery of the Buzzard oil field. These studies were of value in forming BG’s perception of prospect risk and reward and confirming the company’s commitment to drill the prospect. Studies ranged from standard evaluation techniques to application of cutting edge technology of the time to innovative applications of software to address specific uncertainties or risks. BG perceived the prospect to be of moderate to high value, with a substantial upside reward, and since acquisition of 3D seismic to have moderate risk. This perception derived from several factors that may be peculiar to this particular prospect:

•
an existing well with an oil accumulation, located down dip, proving a migration path from oil mature source and the presence of thick sandstone units of excellent reservoir quality, logged and cored

•
tectonic tilting had both accentuated trap relief significantly increasing trap volume, and aided migration direction

•
the abundance of offset well data allowing an understanding of basin history and a robust geological model

Furthermore the BG evaluation benefited from:

•
involvement of in-house specialists in sedimentology, basin analysis and geophysical modelling

•
application of the findings of research projects at Edinburgh and Leeds Universities in the fields of Moray Firth structural development and Turbidite Sedimentation respectively
West of Shetland revisited: the search for stratigraphic traps
Authors: Loizou N. , Andrews I. J. , Stoker S. J. , Cameron D. 
Published: April 2008

Abstract
The West of Shetland area has scope for the stratigraphic entrapment of hydrocarbons at various Jurassic to Palaeogene stratigraphic levels. Mapping and identification of such traps requires a fundamental understanding of the regional geology, the study of analogues and source kitchens, and a thorough approach to trap validation. Since 1982, 47 exploration wells have been positioned on Paleocene prospects with a significant stratigraphic component, but few have found hydrocarbons — many failing as a result of poor trap definition and overconfidence in the predictive use of amplitude anomalies. Hydrocarbon sourcing of many of the failed prospects was also poorly constrained. Few amplitude-related stratigraphic features could be tied with confidence to a viable source kitchen. The presence of a regional seal is a prerequisite ingredient for a successful Paleocene play. Many remaining undrilled, subtle prospects rely on a stratigraphic trapping component, and high-quality 3D seismic data are seen as an essential search tool. Examples of undrilled prospects are presented from the Paleocene of the northern Faroe-Shetland Basin and the Mesozoic of the East Solan Basin and Corona Ridge.
Shallow-marine carbonates of the tropical-temperature transition zone: effects of hinterland climate and basin physiography (late Miocene, Crete, Greece)
Authors: Reuter Markus , Brachert Thomas C. , Kroeger Karsten F. 
Published: April 2008

Abstract

In modern oceans, the transition zone between the tropical and temperature carbonate province is gradual and covers a wide latitudinal belt. Little knowledge exists regarding the geological signatures of this zone. This paper describes a late Miocene (early Tortonian-early Messinian) transitional carbonate system that combines elements of the tropical and cool-water carbonate systems (Iraklion Basin, island of Crete, Greece). As documented in stratal geometries, the submarine topography of the basin was controlled by tilting blocks. Coral reefs formed by
Porites
and occurred in a narrow clastic coastal belt along a central Cretan landmass and steep escarpments formed by faulting. On the gentle dip-slope ramps of those blocks having the widest geographical distribution within the basin, extensive covers of level-bottom communities existed in a low-energy environment. Isolated colonial corals were present in the shallow segments of the ramps. Consistent patterns of landward and basinward shift of coastal onlap in all outcrop studies reveal an overriding control of third- and fourth-order sea-level changes on sediment dynamics and facies distributions over block movements. An increasingly dry climate and the complex submarine topography of the fault-block mosaic kept sediment and nutrient discharge from a central Cretan landmass at a minimum. The skeletal limestone facies therefore reflects oligotrophic conditions and sea surface temperatures near the lower threshold temperature of coral reefs in a climatic position transitional between the tropical coral reef belt and the temperate zone. It is suggested that the recognition of an overall late Miocene aridification trend helps to explain the Mediterranean-wide distribution of shallow-marine carbonates, both cool-water and warm-water, in settings adjacent to uplifting mountain ranges (intramontane basins).
The Southern Marion Platform (Marion Plateau, NE Australia) during the early Pliocene: a lowstand-producing, temperate-water carbonate factory
Authors: Kindler Pascal , Ruchonnet Cyril , White Tim 
Published: April 2008

Abstract
The Southern Marion Platform (Marion Plateau, offshore NE Australia) is a drowned, isolated carbonate platform of Neogene age that was drilled during ODP Leg 194 in January–March 2001. Initial results from the Leg suggested that temperate-water carbonate production was terminated by a phase of subaerial exposure during the late Miocene, and did not resume during the ensuing Pliocene transgression. New petrographic, geochemical, isotopic and biostratigraphical data obtained from samples collected during the cruise show that the Southern Marion Platform was not subaerially exposed during the late Miocene, and further remained intermittently active during the early Pliocene. At that time, its mode of functioning was probably the reverse of that of classical, Bahamian-type, isolated platforms: sediment production occurred during sea-level lowstands and was shut off during highstands.
Chemostratigraphy in Miocene heterozoan carbonate settings: applications, limitations and perspectives
Authors: Mutti Maria , John Cédric M. , Knoerich Andrea C. 
Published: April 2008

Abstract
The temporal variability of geochemical proxies can be used in time intervals characterized by global changes in marine chemistry to achieve improved stratigraphic correlation. The application of this approach in rocks lithified by cementation requires particular attention, as the original isotopic signature may have been modified by diagenetic processes and, when bulk samples are used, could reflect facies-specific compositional changes as opposed to primary changes in the water column. This paper examines sedimentological and chemostratigraphic records from outcrops in the central Mediterranean and cores drilled on the Marion Plateau by the Ocean Drilling Program (ODP) Leg 194, where heterozoan carbonates accumulated during the Miocene. Specifically, the paper addresses how facies and preservation of original marine signatures differentially affect the quality of the dataset. The analysis indicates that, in general, heterozoan systems, relative to their tropical counterparts, show good preservation of marine signatures. Chemostratigraphy offers a viable low-resolution alternative for dating platform sediments considering the general lack of biostratigraphic markers in these settings. It is stressed, however, that care must be taken when interpreting these values, especially when the dataset is at a low resolution or when post-depositional dolomitization took place. Furthermore, chemostratigraphy in shallow-water environments cannot be done without detailed facies analysis, as facies changes may impact bulk-rock stable isotope values.
Archaeometry:
quo vadis
?
Authors: Maggetti Marino 
Published: April 2008

Abstract
First, a brief overview of the tasks and the historical development of archaeometry will be given. Although archaeometry is generally doing well, a few issues currently faced by this discipline will be outlined. These include: (1) funding for projects and research positions; (2) the appeal of archaeometry to a new generation of academics; (3) the standard of publications; (4) the safeguarding of and the immediate access to scientific data.
Fibre-tempered pottery of the Stallings Island Culture from the Crescent site, Beaufort County, South Carolina: a mineralogical and petrographical study
Authors: Smith Michael S. , Trinkley Michael B. 
Published: April 2008

Abstract

Late Archaic to Early Woodland (4500–3000 years
bp
) Stallings Island Culture fibre-tempered plainware pottery is found from northern North Carolina to NW Florida and is often separated into two temper groups (Stalling and Orange series) based upon fibre type. Thirty-four sherds were studied to determine textural or mineralogical characteristics to assist in form and type separation. This study finds that only a few of the sherds were dominated by fibre. The fibre is visible as secondary porosity (voids) with some carbonized remains and exhibits specific shape and orientation at different locations within the sherd. Only two sherds had carbonized stem fragments that allowed identification of the Spanish moss (
Tillandsia usnedoides
). The remainder of the Crescent site plainware pottery has such low (to no) fibre contents as to be indistinguishable from similar age sand-tempered Thom’s Creek wares. The identity and textural features of the fine-grained aplastic minerals (quartz, feldspar, biotite and opaque minerals) in the paste are similar in both fibre- and non-fibre-tempered sherds, and this suggests that the materials used are consistent with sediment extraction from a fluvial coastal plain or estuarine setting. These observations indicate that the degree of fibre incorporation in these sherds may be related to the specific clay source (or manufacturing location) or represent examples of an evolving pottery manufacturing process within the Stallings Island Culture.
Islamic and Hispano-Moresque (múdejar) lead glazes in Spain: a technical approach
Authors: Vendrell-Saz M. , Molera J. , Roqué J. , Pérez-Arantegui J. 
Published: April 2008

Abstract
Islamic and Hispano-Moresque glazes from the 10th to 15th centuries found in various archaeological sites, most of them workshops, are studied to show the technical evolution of the medieval glazing process. The technology seems to show a simplification: the early Islamic glazes were applied on prefired bodies and after fritting a lead-silica mixture, whereas for the later Islamic productions the raw materials for the lead glazes were not fritted and they were applied over unfired bodies. The same simplified technology was used in the Hispano-Moresque workshops. In the Islamic workshops lead glazes were coloured by adding elements (Fe, Cu, Mn), whereas the múdejar technology simplified the process by using only one recipe to produce pots of different colour. This was achieved by applying the glaze in a different manner (on one side of the pot to obtain yellow or on both sides to obtain green), or using different pastes (already used to produce pottery for different uses). Finally, there are differences between Islamic and Hispano-Moresque tin glazes related to the crystal size of the opacifier (tin oxide crystals), which should indicate some technological differences in temperature, glaze composition and the process to obtain the frits because of the high dependence between viscosity, temperature and crystal nucleation and growth.
Archaeometric analyses of game counters from Pompeii
Authors: Arletti R. , Ciarallo A. , Quartieri S. , Sabatino G. , Vezzalini G. 
Published: April 2008

Abstract

Among the glass finds of the Pompeii excavations, numerous objects of opaque and transparent glassy material of different colours were recovered and classified as game counters. The main aims of this work were to characterize these samples so as to identify the materials used as colorants and opacifying agents, and subsequently to deduce the technology used for their production. The results of the chemical and mineralogical analyses obtained for game counters were also compared with those obtained for transparent and opaque glass artefacts. The chemical analyses were carried out, using only 300 mg of sample, by both wavelength-dispersive electron microprobe and X-ray fluorescence analysis. The crystalline phases present in the opaque glass were identified using both an automatic X-ray powder diffractometer and a Gandolfi camera. Secondary and backscattered electron images were obtained to study the distribution and morphology of the opacifier particles, and qualitative chemical analyses were obtained with an energy-dispersive system. All the game counters analysed can be classified as silica-soda-lime glass. Two calcium antimonates (CaSb
2
O
6
and Ca
2
Sb
2
O
7
) were identified in the opaque white, green and blue glass, and Pb
2
Sb
2
O
7
particles were detected in the opaque yellow glass. Particles of metallic copper were detected by both energy-dispersive system and X-ray powder diffraction. These results support the hypothesis that transparent game counters were obtained by remelting of fragments of common transparent artefacts. In contrast, opaque finds were probably produced using the glassy paste employed in the production of mosaic tesserae.
Medieval stained glass windows from Pavia Carthusian monastery (northern Italy)
Authors: Marchesi Valeria , Negri Elisabetta , Messiga Bruno , Riccardi Maria Pia 
Published: April 2008

Abstract
Stained glass windows of the Carthusian monastery (Certosa) of Pavia (15th century) were investigated during a recent restoration campaign, to define chemical compositions and to understand manufacture techniques. Analyses were performed on six stained glass windows, representing S. Caterina (St. Catherine), S. Gregorio (St. Gregory), S. Agostino (St. Augustine), la Natività (the Nativity), S. Bernardo (St. Bernard) and S. Girolamo (St. Jerome), and on two undecorated windows. The methodological approach couples micro-sampling with micro-analyses. The detailed chemical analysis reveals four compositionally distinct glass-types: mixed alkali, soda and two potash glass types. These last two types display a rather constant MgO content but variable CaO content and define two main compositional clusters, CaO rich (Type II) and CaO poor (Type III), that have been ascribed to the pristine glass. The compositional boundary of Type II and Type III glass fits those already defined in recent literature. The mixed alkali and soda glass are considered to be related to later repairs. The narrow compositional cluster represents a good statistical result defining the composition of the pristine glass panes and allows compositional comparisons with stained glass from coeval cathedrals of Northern Europe (Germany, Switzerland and France). Close similarities are found to stained glass from Rouen and St. Maur des Fosses.
Textural analysis of ancient plasters and mortars: reliability of image analysis approaches
Authors: Carò F. , Di Giulio A. , Marmo R. 
Published: April 2008

Abstract
Different image analysis (IA) methods have been developed to compute textural parameters of ancient plasters and mortars using standard petrographic thin sections. These IA routines were applied to samples of materials with different technological characteristics from three historical buildings in the city of Pavia (Northern Italy), covering a period from the 12th to the 19th century. The IA techniques tested in this study belong both to classical digital image processing and to neural network modelling. In the first case, analyses were performed by commercial IA software whereas in the second case a Multi-Layer Perceptron neural network (MLP) was tested. Digital image analysis was performed on images taken by means of a petrographic microscope; additionally, analysis of back-scattered electron (BSE) images was performed. Textural data obtained through the IA applied to thin sections were compared with the data from traditional point counting and mechanical sieve analysis of disaggregated samples of the same materials. The results show that the IA of thin sections provides robust results in a fast and easy way. However, the reliability of the analyses can be prejudiced by textural and compositional heterogeneity of the samples.