bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tectonic evolution of greenstone belts
Authors: Shackleton R. M. 
Published: April 2008

AbstractGranite-greenstone terrains represent the main process by which continental crust was formed in the Archaean; the same process has continued since, at a diminishing rate. Granite plutonism added a layer about ten kilometres thick under the greenstones. From Early Archaean to Late Proterozoic, there was a progressive change in the volcanics; komatiites decreased from the Early Archaean, while the proportion of andesites and felsic volcanics increased. Continent-derived sediments, rare or absent from the Early Archaean, increased through time.Tectonic deformation in the greenstone belts is separable into pre-diapiric, diapiric and post-diapiric. The first deformations were translational, mainly flat thrusts, the second compressional without crustal shortening, the third involved crustal shortening. Only the diapiric structures are an essential element of greenstone belt evolution but the others are generally important. The pre-diapiric and diapiric structures are related to subduction; the post-diapiric structures may be accretionary or collisional. Granite-greenstone terrains show only minor crustal thickening. Some adjacent high-grade terrains were intensely deformed, and the crust greatly thickened, by continent-continent collision.
Archaean deformation patterns in Zimbabwe: true indicators of Tibetan-style crustal extrusion or not?
Authors: Treloar Peter J. , Blenkinsop Tom G. 
Published: April 2008

Abstract

Recent models of the structural evolution of the Zimbabwe Archaean craton have stressed the role of WSW-trending sinistral strike-slip shears in accommodating the WSW-directed extrusion of crust thickened in response to NNW-SSE compression and shortening. This relationship between crustal thickening and crustal extrusion is analogous to the structural response of Tibetan crust to the Tertiary collision of India and Asia. We have re-examined many of the structures of the Zimbabwe craton and find the extrusion model largely untenable. Instead, a conjugate set of ESE-striking dextral shears and NNE-striking sinistral shears have been identified, on both regional and outcrop scale, which apparently reflect part of the structural response of the Zimbabwe crust to NNW-SSE shortening resultant from collision of the craton with the Central zone of the Limpopo belt to the south. This collision, at about 2.58 Ga, post-dated the 2.68 Ga aged collision between the Central zone and the Kaapvaal craton which represents the Limpopo orogeny sensu stricto. The suture between the Zimbabwe craton and the Central Zone was re-activated at
c.
2.0 a as a major intracontinental dextral strike-slip shear zone. Partial melting of the lower crust at
c.
2.58 Ga accompanied thickening of the Zimbabwe Archaean crust following collision with the Central zone. The conjugate shears deform fabrics that date from that collision, are synchronous with, or post-date, granite emplacement and may have acted as conduits for transport of the Chilimanzi monzogranitic magmas from the lower to the upper crust. Contacts between greenstone belts and granites are commonly sheared. These marginal shear zones are often parallel to the regional conjugate shears, although local variations in stress trajectories imposed by pluton emplacement may result in them being non-parallel to the major shears.
The generation and assembly of an Archaean supercontinent: evidence from the Yilgarn craton, Western Australia
Authors: Myers John S. 
Published: April 2008

Abstract
The Yilgarn craton consists of granites, greenstones and granitic gneisses ranging from at least 3730 to 2550 Ma. These rocks can be divided into a number of tectonostratigraphic terranes that comprise distinct rock units with different geological histories. However all the terranes, regardless of their age and composition, show evidence of intense tectonic, volcanic, plutonic, and metamorphic activity between 2780 and 2630 Ma. This is interpreted as a major episode of plate tectonic activity which swept together and amalgamated a number of diverse crustal fragments (including volcanic arcs, back-arc basins and microcontinents) to form a super-continent, of which the Yilgarn craton is a fragment. The main features of the Narryer, Murchison and Kalgoorlie terranes are described as examples of the diversity of crustal components within the craton and the nature of the processes by which these components were combined to form the Yilgarn craton.
Late Archaean structure and gold mineralization in the Kadoma region of the Midlands greenstone belt, Zimbabwe
Authors: Herrington R. J. 
Published: April 2008

Abstract
Major Archaean greenstone gold deposits are located in distinctive structural settings, and Zimbabwe is a good example with over 90% of its gold production being derived from structurally controlled veisns, shear zones and probably epigenetic replacement BIF hosted deposits.

The structural framework of the Zimbabwe craton is dominated by the evolution of the
c.
2700 Ma Limpopo belt. Strongly developed, major shear zones were initiated at this time. These major shear zones focused strain, which in the Midlands greenstone belt, evolved from pure N-S compression, to lateral extrusion of the main Rhodesdale gneiss block westwards.

The structural features seen in the gold deposits of the Midlands greenstone belt are consistent with such a model of NNW-SSE compression linked to lateral extrusion of the Rhodesdale gneiss block westwards. Initiation of structures during NNW-SSE compression resulted in early folding such as the Kadoma anticline, together with initiation of the major mineralized shear systems as thrust faults. Simple shear evolved to transpressive shear with development of oblique dextral and sinistral mineralized shear systems. Rotation of the principal stress direction clockwise to an ENE-WSW orientation led to evolution of dominantly dextral transpressive shear on the major Lily, Munyati and Rhodesdale boundary shear systems, probably in response to the lateral extrusion of the Rhodesdale gneiss block westwards. This even is linked to waning gold mineralization and accounts for the major dextral offsets along the Lily fault and the Munyati shear close to Battlefields.
Palaeotidal modelling of continental shelves: marine implications of a land-bridge in the Strait of Dover during the Holocene and Middle Pleistocene
Authors: Scourse J. D. , Austin R. M. 
Published: April 2008

Abstract

Numerical models of the tide on the NW European continental shelf are useful in predicting basic tidal dynamics (amplitude, current, bed stress, mixing) from bathymetry, coastline configuration and a known ocean tide at the shelf edge. Using the
M
2
constituent of the ocean tide, a numerical model has been used to investigate the tidal regime of the English Channel/southern North Sea at successive stages during the Holocene transgression, and also during the maximal sea-levels of Middle Pleistocene temperate stages, by incorporating palaeogeographical interpretations of geological data from these time-slices. Prior to the breaching of the Strait of Dover in the early Holocene, the Southern Bight of the North Sea was a quiet, shallow embayment of low
M
2
tidal amplitude (<0.5 m); following breaching it attained the present state of vigorous tidal action with mean amplitudes of around 2 m. Changes in sediment transport paths and shelf-sea fronts are also indicated. Models of the Middle Pleistocene interglacial English Channel incorporate modified palaeobathymetries to compensate for tectonic uplift in the central Channel area over the past 400 000 years. These models indicate increased seasonal stratification in the Channel compared with the present mixed condition. This is in agreement with independent evidence from coccolith assemblages contained within sediments of the same age from the central Channel area.
Malacological evidence relating to the insularity of the British Isles during the Quaternary
Authors: Meijer T. , Preece R. C. 
Published: April 2008

AbstractThe marine molluscan faunas from different temperate stages of the Pleistocene of the North Sea vary enormously both in terms of species richness and in the diversity of their biogeographical composition. The marine assemblages from the Middle Tiglian, Eemian and Holocene have all yieldedc.100 species or more, including many with southern or ‘Lusitanian’ affinities. It is thought that during these stages the Strait of Dover was open, allowing entry of these southern taxa into the southern North Sea. Conversely, the temperate stages from the Late Tiglian up to and including the Holsteinian have yielded relatively impoverished faunas (no more than about 40 species) virtually lacking any of the southern elements. During these stages it would appear that the Strait of Dover was closed, so preventing the spread of marine molluscs into the North Sea. Examination of the history of fluvial molluscs (particularly prosobranchs and larger bivalves) on either side of the English Channel supports this interpretation. Fluvial provinciality is recognized during the stages when Britain is thought to have become an island. Non-provinciality, pointing to fluvial exchange, occurs during the other stages.
Insularity of the British Isles 250 000–30 000 years ago: the mammalian, including human, evidence
Authors: Sutcliffe Antony J. 
Published: April 2008

Abstract

During the Middle-Late Quaternary the British Isles have alternately been part of the Continent of Europe and separated from it by the sea. Comparison of mammalian faunas from sites on both sides of the present English Channel can contribute to the reconstruction of Britain’s island history. The most suitable chronological framework for this study is discussed. Attention is drawn to problems of applying the 1973 scheme of the Geological Society of London, which is used here only in conjunction with the more straightforward chronology of the deep-sea oxygen isotope record. Special attention is directed to events during the period of time
c.
250 000 to 30 000 years
bp
. The chalk land-bridge that had previously joined the British Isles to the Continent of Europe had by this time been breached, and any further changes in the land connection are likely to have been the result of eustatic changes of sea-level, associated with glacial-interglacial fluctuations of climate.

Whether the British Isles became isolated from the Continent during the high sea-level phase that occurred during isotope stage 7 is uncertain from the mammalian evidence. The occurrence of human artefacts and remains of pond tortoise
Emys orbicularis
, which is unlikely to have tolerated salt-water, in deposits representing the earliest part of this stage, suggests a land connection then or not very long previously. Human presence continues into isotope stage 6, characterized also by the arrival of steppe rodents from eastern Europe; evidence of a further episode of low sea-level.

During the Last Interglacial, oxygen isotope stage 5e, sea-level rose once more, isolating the British Isles from the Continent. Remarkably, humans, horses and the mollusc
Corbicula fluminalis
, so common previously, fail to reappear, a consequence, perhaps, of being cut off by rapidly rising sea-level at the end of stage 6. A very characteristic fauna, including hippopotamus, straight-tusked elephant, narrow-nosed rhinoceros, fallow deer and abundant carnivores, did nevertheless manage to become established throughout England and Wales at this time, some as far north as Durham.

Falling sea-level associated with the Devensian (isotope stages 5d-2) re-established the land connection. Hippopotamus had by this time disappeared and been replaced with a fauna including woolly mammoth, woolly rhinoceros and reindeer. Humans and horses returned once more. It was not until sea-level rose again during the Holocene that the British Isles became finally isolated from the Continent, as they are today.
Evidence for Pleistocene contact between the British Isles and the European Continent based on distributions of larger carnivores
Authors: Turner Alan 
Published: April 2008

Abstract
The generalized ecological tolerances of larger terrestrial carnivores, reflected in their wide distributions in fossil and living faunas, make them good potential indicators of the changing pattern of links between Britain and the continent of Europe over time. Extensive contact is indicated until the earlier part of the Middle Pleistocene, that is prior to the Anglian-Elsterian glaciation. The pattern after that is more complex, with evidence for some form of marine barrier by the time of the Hoxnian and for complete isolation during the Last Interglacial.
An overview of database analysis and design for geological systems
Authors: Rasmussen Ken 
Published: April 2008

Abstract
Techniques for database analysis and design are well established for the development of administrative systems. When the techniques are used to develop geological databases, however, a number of difficulties arise. This paper provides an introduction to the nature of these problems. The context for the discussion is first set by describing the standard techniques for database analysis and design. The difficulties that arise when the techniques are applied to geological data are then reviewed. The paper concludes with a discussion of some recent developments in database analysis and design which will assist designers of geological systems.
Improving the value of geological data: a standardized data model for industry
Authors: Saunders Michael R. , Shields John A. , Taylor Michael R. 
Published: April 2008

Abstract
The preservation of observed geological data in a standardized and digitally accessible form presents a challenge. Geological data objects range in scale from the macroscopic, e.g. outcrop and core, to the microscopic, e.g. drill-cuttings. Each change in scale has a direct effect on apparent heterogeneity, which may result in contradictory data, and the providers of the observations may have widely differing degrees of experience. A system has been developed for the definitive description and preservation of features in core and drill-cuttings using workstations. It provides the opportunity to extract definitive individual attributes from geological descriptions with a minimum of extra effort. These digitally stored data are represented graphically, textually and symbolically to construct geological logs. Geological data may be presented in combination with drilling and mud gas data, Measurement While Drilling (MWD) and wireline logging data, and off-site analyses, to produce composite formation evaluation logs, as well as being exported in customized file formats, thereby enhancing the value of all data through integrated information management.
Towards the creation of an international database of palaeontology
Authors: Lhotak M. , Boulter M. C. 
Published: April 2008

Abstract
The Plant Fossil Record (PFR) database is being built to include biological, geological, geographical and bibliographic information of all authoritative plant fossil citations throughout the world. The interactions between these have created standardized records from different sources and programs have been written to add and reorganize data. Techniques such as optical character recognition (OCR), e-mail and diversity interfaces are used. Interdisciplinary and cultural aspects of this ambitious project are being considered. The work is to help as many different specialists as possible to use palaeontological data and to relate these data to evolutionary and biostratigraphic problems as well as to climatic aspects of global change. The structure of the database comprises some original features. It is a temporal facility: each edit or addition is timed and dated so that its state at any particular time can be recalled. Geological time and the associated global palaeogeography are also built into the database giving a time dimension to record likely evolutionary trends.
The use of text databases in the management of exploration data
Authors: Mallender S. C. R. 
Published: April 2008

Abstract
The management of exploration data concerns all the things that happen to a piece of exploration data during its life, and the management of the physical data is controlled by the information used to describe it. A description of the data forms part of a contract between a company and a recording contractor before the physical data even come into existence. Descriptive information about each data item and each dataset is recorded and re-recorded on many transmittals as the physical data move from recording contractor, to processing contractor, to storage contractor. The ‘computerized catalogue’ listing, which a storage contractor provides to an exploration company is often the only record of what is available, and the legal ownership records of these data are often stored elsewhere. The amount of this reference information used to describe exploration data (for example, the name and extent of a map or a line, the title of a report, the reference number of a tape) varies significantly from one data type to another, and the amount actually recorded often varies from one record to the next. Historically, there has been a lack of consistency throughout the industry in the terms used, and the number of those terms employed when describing and referring to exploration data. This poses problems in the management of exploration data.
The main problem concerns the storage, retrieval and transmission of this descriptive information; the information is rarely ‘processed’ as such. From a database point of view, the problem is to store large quantities of quite disparate and unstructured information, to find rapidly what has been stored, and to retrieve the information easily in a (re-)usable form.
Text databases are ideal in these circumstances: they can hold completely unstructured information, and allow users to find records using any data that appear anywhere in the content of the record. Accompanying software is used to provide a user interface to the text database, and this enables sophisticated systems which are very user-friendly to be developed easily.
The geological data manager: an expanding role to fill a rapidly growing need
Authors: Lowe D. J. 
Published: April 2008

Abstract
The management of geological data—raw, inferred and derived—has been neglected for many years. Where such management was attempted, the staff responsible were commonly non-specialists, and most were under-supported and under-valued. Expanding use of digital systems in the geological sciences and growing acceptance of a need for quality management of data in an increasingly business-orientated and competitive world have necessitated reappraisal of data management needs and the role of the geological data manager. The importance of supporting work to develop data verification and validation procedures and the means to assess and ensure data quality is gaining recognition. Some 20 years after the first major incursion of digital technology into the field of geology, the value of the data already gathered, and thus the importance of geological data management, is only now beginning to be appreciated and accepted. In the near future the geological data manager’s role is expected to expand rapidly to address the needs of geological activity.
The quality assurance of geological data
Authors: Duller Paul R. 
Published: April 2008

Abstract

The key to success in any geological investigation is access to accurate and reliable information. Clear strategies are required to ensure that geological information, often acquired at great expense, is not mislaid and is kept in a form that can benefit its owners. To meet this need requires the provision of a reliable data management strategy, a well-defined and efficient policy of administration and a clear understanding of the nature, origin and quality of data involved. Geological data by their very nature pose particular problems in terms of compilation, quantification and validation. However, the application of standard quality control, quality assurance and audit procedures can be used to ensure the
correctness
(or accuracy) of the data, thereby safeguarding the integrity of any associated investigation.
Project databases: standards and security
Authors: Henley Stephen 
Published: April 2008

Abstract
For technical applications in the mining industry, large institutional data models are the exception rather than the norm. Much more common, given the distributed nature of the business, and the scattered locations of the specialists involved, is the personal or project database. Such a database is set up for a project (or part of a project), and is developed using a data model defined specifically for that project. At the end of the project, the database may be archived or it may be supplied to a central group for integration with a corporate database. If uncontrolled, such methods of database management can lead either to direct drastic loss of data or to incompatibilities in data recording standards. The use of common software standards and data dictionaries throughout an organization can reduce radically these dangers and can produce positive benefits not only in data recovery but in reusability of techniques.
Database applications supporting Community Research Projects in NERC marine sciences
Authors: Lowry Roy K. , Cramer Raymond N. 
Published: April 2008

Abstract
Traditionally, oceanographic data management has been strongly cruise oriented. However, the organization of research into Community Research Projects, such as the North Sea Project and Biogeochemical Ocean Flux Study (BOFS), has produced a requirement for handling multidisciplinary data from a large number of research cruises as an integrated dataset. The code of practice for the project dictated that data were to be exchanged freely between project participants throughout the duration of the project, after which the data were to be brought into the public academic domain. The data management strategy therefore had to provide both a vehicle for data exchange within the project and a mechanism for subsequently making the data available to a wider community.
These problems were solved by BODC through the adoption of two technologies. Relational database technology was used to integrate the data and, through access over the UK academic wide area network (JANET), provide the data exchange mechanism. Electronic publication of the datasets on CD-ROM provided the mechanism for expanding the dataset user base.