bluuebunny/crossref_metadata_2025_split huggingface dataset:
A GPR study of sedimentary structures within a transgressive coastal barrier along the Danish North Sea coast
Authors: Møller Ingelise , Anthony Dennis 
Published: April 2008

Abstract
The Danish North Sea coast is characterized by the presence of coastal barrier systems. One of these systems, the Holmsland Barrier, is a transgressive wave-dominated barrier. For the purpose of studying large-scale architecture in a transgressive barrier, as well as small-scale sedimentary structures, a ground penetrating radar (GPR) field experiment has been carried out. The study focuses on the identification of high-amplitude reflections of the large-scale architecture of the barrier and the recognition of small-scale structures for interpretation of coastal processes. The observed radar facies fall into two groups, both interpreted as storm washover deposits. One group, dominated by parallel to subparallel reflection, is related to the seaward horizontal stratification in the washover fans. The other group, dominated by sigmoid and oblique clinoforms, is related to delta foreset stratification, indicating that the washover fans are terminated in standing water. The observations derived from the GPR study of the Holmsland Barrier suggest that this transgressive barrier is composed almost entirely of washover deposits with local small amounts of aeolian deposits. This study has shown that the GPR method is outstanding in mapping both large-scale architecture and small-scale internal structures in a coastal barrier.
Sedimentary architecture and radar facies of a fan delta, Cypress Creek, West Vancouver, British Columbia
Authors: Roberts M. C. , Niller H. -P. , Helmstetter N. 
Published: April 2008

Abstract
Fan deltas are common depositional features along the macro-tidal, fjorded coast of southern British Columbia. To determine the sedimentary architecture of the Cypress Creek fan delta, West Vancouver, British Columbia, a combined ground penetrating radar and geomorphological study was carried out. Five radar facies were identified and their associated geomorphic environments were established: oblique clinoform radar facies (delta front); mounded radar facies (debris-flow deposits); undulating subhorizontal radar facies (beach zone); concave radar facies (river channels) and horizontal radar facies (salt-water intrusion). The delta plain was formed primarily by debris flows, some of which reached the delta front to form prograding foreset beds. Radar facies analysis established the occurrence of arcuate scars and masses of slumped material, signifying mass movement on the delta front. Wave action, working over a 4.9 m tidal range, has reworked the distal delta-plain debris-flow sediments into an armoured gravel beach. A depositional model is proposed for a fan delta in a macro-tidal fjord setting.
The use and application of GPR in sandy fluvial environments: methodological considerations
Authors: Woodward John , Ashworth Philip J. , Best James L. , Sambrook Smith Gregory H. , Simpson Christopher J. 
Published: April 2008

Abstract
Ground penetrating radar (GPR) is a popular technique for imaging and interpreting sedimentary architecture. However, current literature shows a wide range in the quality of information provided on the GPR methodology and processing technique. It is therefore difficult to judge the validity of the GPR interpretations and this produces inherent difficulties for comparison between surveys. This paper describes the key steps required to collect, process and interpret GPR surveys in sandy fluvial sediments. GPR data from the South Saskatchewan River, Canada, are used to illustrate each stage of data collection and processing. Particular attention is given to the appropriate set-up conditions for the GPR software and hardware, the selection of data-processing techniques and velocity analysis. Methods for the interpretation of GPR reflectors are also investigated using ground-truth control provided by a cut-face exposure. This paper presents recommendations for a systematic and rigorous methodology for the collection, processing and interpretation of GPR data in sandy fluvial environments. The paper suggests that all data-collection parameters and processing steps should be recorded or tabulated in any GPR publication to facilitate comparisons between surveys.
GPR derived architecture of November 1996 jökulhlaup deposits, Skeiðarársandur, Iceland
Authors: Cassidy N. J. , Russell A. J. , Marren P. M. , Fay H. , Knudsen Ó. , Rushmer E. L. , Van Dijk T. A. G. P. 
Published: April 2008

Abstract

Skeiðarársandur in southeastern Iceland, with an area of > 1000 km
2
, is the world’s largest active proglacial outwash plain. In July–August 2000, a total of over 10 km of ground penetrating radar (GPR) profile data (at 50 MHz and 100 MHz) was collected from a variety of proglacial outwash sediments across the Gígjukvísl channel region of the Skeiðarársandur plain. GPR-profile results and their corresponding facies interpretations are presented for the flood deposits of a single supraglacial outwash fan and its associated source-proximal ice-walled canyon created entirely by the November 1996 jökulhlaup event. By combining the GPR data with ground surveying, photogrammetry and detailed sedimentary outcrop evidence, this study adds a new perspective to the large-scale analysis of single, high-magnitude flood events and the sedimentary record of former, ice-proximal outwash plains. The GPR derived architectures point to a higher degree of sediment reworking than predicted by previous sedimentary models and may provide a useful analogue for the study of sedimentation within similar bedrock fluvial and alluvial fan feeder systems.
Visualization and characterization of active normal faults and associated sediments by high-resolution GPR
Authors: Reiss Stefan , Reicherter Klaus R. , Reuther Claus-Dieter 
Published: April 2008

Abstract
Ground penetrating radar (GPR) is applied here to visualize sedimentary structures related to recent deformation. Several 200 MHz GPR profiles perpendicular to active normal faults in Spain and Italy were analysed. The El Camp normal fault with associated sedimentary and tectonic patterns in northeastern Spain serves as test site. Faulted alluvial and colluvial sediments of the Pleistocene were studied in a trench for direct comparison with GPR profiles. GPR investigations across buried faults from several localities are compared to these observations in a case study. The hanging walls of these faults form half-grabens or grabens, which are generally characterized by internal asymmetric, concave, displaced reflectors or wedge-like features comparable to sedimentary features in adjacent outcrops. The examples demonstrate that high-resolution GPR profiling provides not only the possibility to trace and map active normal faults but also to visualize the associated sedimentary hanging-wall patterns in the subsurface, such as heterogeneous graben and half-graben structures, including coarse-grained clastic wedges. Quantitative and qualitative GPR evaluation of those wedges yields a certain possibility of estimation of palaeomagnitudes and slip rates on active normal faults. We regard high-resolution GPR as an additional tool in pretrenching palaeoseismological investigations.
Tectonic control on changes in sediment supply: Quaternary alluvial systems, Körös sub-basin, SE Hungary
Authors: Thamó-Bozsó Edit , Kercsmár Zsolt , Nádor Annamária 
Published: April 2008

Abstract
The Pannonian Basin of Hungary is Europe’s largest inter-mountain basin, where an evolution in drainage development patterns during the Quaternary was caused by changes in sediment flux to the basin, the dynamics of basin morphology development and the uplift history of the Apuseni Mountains source area, all directly or indirectly related to the tectonic systems operating in the region. Micro-mineralogical data of detrital heavy minerals from modern rivers and two key boreholes covering a time span from the present back to 2.6 Ma have been grouped by statistical analysis into two main clusters and some sub-clusters. The samples within the same cluster have a similar composition, and originated from the same source area. Based on the similar palaeogeographical setting of the potential source areas during the Quaternary, it has been possible to extrapolate the present transport directions of the rivers with a well-known catchment area geology and the heavy mineral composition to Pleistocene borehole data. The changes in transport directions were clearly sharp and related to significant changes in the uplift history of the Apuseni Mountains catchment area. During the Pliocene and Early Pleistocene the compressional stress field operating in the East Carpathians region resulted in the thrust-driven uplift of the Apuseni Mountains and the formation of a syn-sedimentary trap at the western margin of the source area, which captured the sediments of short, transverse rivers. During this period the drainage of the study area was characterized by axial drainage parallel to this trap, and sediments were transported from the northeast, also shown by micro-mineralogical data of detrital heavy minerals. At about 1.95 Ma this trap stopped being active due to the release of the compressional stress field and the isostatic uplift of the Apuseni Mountains, together with the adjoining basin area. This resulted in the filling of the thrust-bounded trap, and the development of transverse drainage, which was shown by characteristic SE transport directions, based on micro-mineralogical data in the study area, and also by an increase of sediment flux. The axial capturing shifted further to the west, developing a configuration approaching to the present river course pattern. By analogy with the Himalayan foreland and retro-arc basins of the Cordilleran-Andean ranges, it was demonstrated that tectonic activity exerts a strong control on the drainage pattern through its influence on variations in sediment supply.
Sediment budgeting techniques in gravel-bed rivers
Authors: Brewer P. A. , Passmore D. G. 
Published: April 2008

Abstract
The difficulties in obtaining reliable sediment transfer data from direct field measurement or from sediment transport formulae are widely recognized by geomorphologists and river engineers. Quantifying morphological changes (erosion and deposition) in rivers by the analysis of archive data or by field survey, however, can overcome many of these difficulties and provide a mechanism by which sediment budgets can be calculated over a variety of spatial and temporal scales. This paper applies three sediment budgeting methods based on morphological changes in a hypothetical braided reach. These methods range from a simple two-dimensional planform budget to more sophisticated three-dimensional cross-profile and morphological budgets. The development of each budget technique is described and the limitations and applicability of each identified. The three methods are then used to calculated sediment transfer rates in a multi-thread reach on the River Severn in mid-Wales, UK. Results show that across four budget periods spanning 2.5 years the reach was a net exporter of sediment. Application of the planform budget to eight time periods since 1836 shows a similar pattern of net sediment export in the nineteenth century, but during the majority of the twentieth century the reach was a net sediment sink. Finally, the applicability of applying budgeting techniques to extended centennial and millennial timescales is discussed and an assessment made of the role they might play in advancing our understanding of Holocene river dynamics and informing sustainable river management practices.
Transverse rivers draining the Spanish Pyrenees: large scale patterns of sediment erosion and deposition
Authors: Jones Stuart J. 
Published: April 2008

Abstract

Data collected from six transverse rivers draining the Spanish Pyrenees highlight how the rate of change in river gradients downstream controls long-term deposition and erosion patterns acroos the mountain belt. The rivers draining the Spanish Pyrenees provide evidence for an important relationship between gradient (
S
) and distance from the drainage divide (
x
), such that
S
is proportional to
x
Ω
. This can be expressed quantitatively as a power function relation
S
∞
L
−R
. In areas dominated by erosion Ω has a value > − 5, while in areas of deposition Ω has a value < −0.4. The contrast between areas of erosion and deposition is also reflected in downstream increases and decreases, respectively, in stream power and bed shear stress along the whole of the mountain front.

It is proposed, based upon previous empirical studies of loose to semi-armoured channels, that the downstream variations of stream power and bed shear stress result in variations of bed-load transport rates, which in turn create the erosional and depositional patterns associated with variations of channel gradient.
These results highlight the complex response of the fluvial system, emphasizing the need for regional approaches for examining long-term changes in rivers draining orogenic belts and the importance for incorporation of hydraulic data into geomorphological models to assist interpretations of the mass distribution of sediment.
The flux of siliciclastic sediment from the Iberian Peninsula, with particular reference to the Ebro
Authors: Evans Graham , Arche Alfredo 
Published: April 2008

Abstract
Today, the main flux of sediment from the Iberian Peninsula is carried to the Atlantic Ocean by westerly or northwesterly flowing rivers. The only major contribution of sediment from Iberia to the Mediterranean is that carried by the Ebro River, which flows along a foreland basin before cutting through the Catalan Ranges to form a delta in the adjacent Valencian Trough of the Mediterranean. During the Cretaceous and Early Eocene the sediment flux was to the northwest in this part of Iberia. During Late Eocene-Tortonian times it was mainly centripetal, as in other Tertiary Basins in Iberia. Beginning in the Seravallian-Tortonian the main flux of sediment has been to the adjacent Valencian Trough of the Mediterranean. This change in direction, it is proposed, was initiated in Pre-Messinian times by a small river cutting back into the Ebro Basin by headward erosion and was possibly aided, or even induced, by changes in palaeo-slope during contemporaneous rifting along the Mediterranean coast.
Geology: from an Earth to a planetary science in the twentieth century
Authors: Marvin Ursula B. 
Published: April 2008

Abstract

Since the opening of the Space Age, images from spacecraft have enabled us to map the surfaces of all the rocky planets and satellites in the Solar System, thus transforming them from astronomical to geological objects. This progression of geology from being a strictly Earth-centred science to one that is planetary-wide has provided us with a wealth of information on the evolutionary histories of other bodies and has supplied valuable new insights on the Earth itself. We have learned, for example, that the Earth-Moon system most likely formed as a result of a collision in space between the protoearth and a large impactor, and that the Moon subsequently accreted largely from debris of Earth’s mantle. The airless, waterless Moon still preserves a record of the impact events that have scarred its surface from the time its crust first formed. The much larger, volcanic Earth underwent a similar bombardment but most of the evidence was lost during the earliest 550 million years or so that elapsed before its first surviving systems of crustal rocks formed. Therefore, we decipher Earth’s earliest history by investigating the record on the Moon. Lunar samples collected by the
Apollo
astronauts of the USA and the robotic
Luna
missions of the former USSR linked the Earth and Moon by their oxygen isotopic compositions and enabled us to construct a timescale of lunar events keyed to dated samples. They also permitted us to identify certain meteorites as fragments of the lunar crust that were projected to the Earth by impacts on the Moon. Similarly, analyses of the Martian surface soils and atmosphere by the
Viking
and
Pathfinder
missions led to the identification of meteorite fragments ejected by hypervelocity impacts on Mars. Images of Mars displayed landforms wrought in the past by voluminous floodwaters, similar to those of the long-controversial Channeled Scablands of Washington State, USA. The record on Mars confirmed catastrophic flooding as a significant geomorphic process on at least one other planet. The first views of the Earth photographed by the crew of
Apollo 8
gave us the concept of ‘Spaceship Earth’ and heightened international concern for protection of the global environment.
Arthur Holmes’ unifying theory: from radioactivity to continental drift
Authors: Lewis Cherry L. E. 
Published: April 2008

Abstract
Only ten years after the discovery of radium in 1897, Arthur Holmes (1890–1965) began his studies at the Royal College of Science in London where he completed the very first U/Pb age determination designed specifically for that purpose. His continued interest in radioactivity and its effect on the thermal history of the Earth led to his early recognition that the age of the Earth should be measured in thousands, not hundreds, of millions of years, a subject he pursued for the rest of his career, despite considerable opposition from traditional geologists. Following a short period in Burma, he returned in 1922 to find that not only had attitudes to the age of the Earth changed, but that geologists were embroiled in a new controversy over continental drift. Evidence is put forward that suggests Holmes may have been aware of Wegener’s theories virtually from the time they were proposed, and that by 1924 he was already searching for his own theory which would explain all geological processes. His profound understanding of the effects of radioactivity on the internal processes of the Earth, and his advanced knowledge of petrology, placed him in a unique position to develop a mechanism for driving continental plates around the globe. The progression of his ideas for this mechanism — convection currents in the mantle — and the unifying theory that that led to, is traced through his papers and letters to colleagues.
Russian geology and the plate tectonics revolution
Authors: Khain Victor E. , Ryabukhin Anatoly G. 
Published: April 2008

Abstract
The suggestion of the concept of ‘scientific revolution’ by Thomas Kuhn in 1962 was, in itself, a significant event in the history of science, and ‘crucial’ episodes or ‘paradigm shifts’ have come to be of special interest in the history of geology (as in other sciences). The appearance of a new paradigm is commonly associated with attempts by the most talented and well-established practitioners to consolidate or sustain the position of the previously prevailing paradigm. For almost 40 years, global theories in geology have been developing under the influence of mobilist ideas. It is no secret that in Russia the mobilist school initially met with serious opposition, and that even up to the present it has had numerous opponents. However, Western, and especially popular, scientific literature usually exaggerates the intensity of the situation and underestimates the contribution of Russian geologists and geophysicists to the development of mobilism and plate tectonics. The present paper describes some of the debates in Russia concerning mobilist doctrines, the work done in that country in the last three decades of the twentieth century from a mobilist perspective, and various theories that had currency in Russia at the end of that century.
‘As chimney-sweepers, come to dust’: a history of palynology to 1970
Authors: Sarjeant William A. S. 
Published: April 2008

Abstract
A brief overview is given of the various fields of palynology, their practical applications being stressed. Particular attention is thereafter paid to the history of palaeopalynology, here considered as the study of pre-Quaternary palynomorphs. This is presented as three stages: the period of pioneer discoveries (to 1918); years of slow progress (1919–1945); and a post-World War II period of accelerating discoveries (1946–1970). Developments concerning the different groups of palynomorphs during these periods are successively presented, under six headings: spores and pollen; dinoflagellates (and acritarchs); prasinophytes; scolecodonts; chitinozoans; and other palynomorphs. The changes brought about in palynology by improving preparation techniques and microscopical equipment are stressed. A brief overview is attempted concerning the developments since 1970, consequent upon ever-expanding research, new preparation techniques and new technology. As conclusion, an overview is presented of the history of palynology and likely future developments are discussed.
Collecting, conservation and conservatism: late twentieth century developments in the culture of British geology
Authors: Knell Simon J. 
Published: April 2008

Abstract
The last three decades of the twentieth century saw a transformation of the place and influence in British society of two cultural themes: environmental conservation and the values of political conservatism. These are here used to examine cultural change in the science of geology at two levels of resolution. First, the micropolitics of the science are revealed through a study of collecting in an era of conservation. Here the scientific hegemony confronted the more populist and commercially driven wings of geology. This was a period of campaign and conflict, leading to the eventual accommodation of opposing views. The second section examines the macropolitics of the science’s institutional infrastructure through a study of a science in a period of recession and under the control of an ideologically motivated Conservative government. The challenge for science was to acquire appropriate government patronage. Here patterns of decline and growth in the science are revealed, driven by supposedly ‘external’ factors. Both perspectives show how the notion of accountability became critical to the science at all levels, and how, in an era which saw the revolutionizing of mass communication, language became fundamental to the political progress of the science.
Phylogeny of the Reedocalymeninae (Trilobita): implications for Early Ordovician biogeography of Gondwana
Authors: Turvey Samuel T. 
Published: April 2008

Abstract

The shallow-water
Neseuretus
Association has been recognized by many authors as an important indicator of the former extent of Gondwana during the Early Ordovician. Phylogenetic relationships of the Reedocalymeninae (Arenig-?Early Silurian) were investigated using cladistic analysis, incorporating 22 species of
Neseuretus
as well as representatives of all other reedocalymenine genera. The area cladogram derived from this analysis contains four subclades each containing areas that span much of the palaeogeographic extent of Gondwana, which are interpreted as representing separate biogeographic events during the evolution of the subfamily. As the majority of taxa included in the analysis are associated with shallow shelf facies, this suggests that no significant environmental barriers existed across the continent during the Early Ordovician. Consideration of area relationships both for different subclades within the area cladogram, and within a consensus area cladogram, also supports the idea of a faunal cline between eastern and western Gondwana during this time interval. Further cladistic analysis of different trilobite taxa can be used to test these ideas.