bluuebunny/crossref_metadata_2025_split huggingface dataset:
Timing of Extension on the Büyük Menderes Graben, Western Turkey, and Its Tectonic Implications
Authors: Bozkurt Erdin 
Published: April 2008

Abstract
The Büyük Menderes Graben is one of the most prominent structures of western Anatolia (Turkey) and borders the Aegean. New structural and stratigraphic evidence demonstrates that the (?)Miocene fluvio-lacustrine, coal-bearing red clastic sediments exposed along the northern margin of the graben are northward back-tilted, locally folded and overlain unconformably by horizontal terraced Pliocene-Pleistocene sediments. Also, there is no evidence that these red clastics at the base of the Neogene sequence were deposited during neotectonic extension. It is suggested here that these sediments cannot be regarded as passive neotectonic graben-fill deposits.

This new evidence further indicates that the age of the modern Büyük Menderes Graben is Pliocene, younger than previously considered (Early-Middle Miocene) and that initiation of north-south neotectonic extensional tectonics in the graben, and thus in western Anatolia, is unlikely to have resulted from orogenic collapse. The Pliocene estimate of the start of extension is in close agreement with the start of slip on the North Anatolian Fault Zone. The north-south extensional tectonics, and associated east-west faulting and basin formation, commenced during the Pliocene due to the effect of westward tectonic escape of the Anatolian block along the North and East Anatolian Faults. New mammal evidence also constrains the start of slip on the younger faults which bound the present-day graben floor to
c
. 1 Ma.

The Büyük Menderes Graben has experienced a two-stage extension. An initial extension (latest Oligocene-Early Miocene) along initially moderately, steeply dipping normal faults was superseded by movement on steeper normal faults during the (?)Pliocene. The two phases of deformation appear to reflect significant changes in the tectonic setting of western Anatolia and are attributed to orogenic collapse followed by tectonic escape.
Petrogenesis of Basalts from Southern Turkey: the Plio-Quaternary Volcanism to the North of İskenderun Gulf
Authors: Yurtmen Sema , Rowbotham George , İşler Fikret , Floyd Peter A. 
Published: April 2008

Abstract

The Quaternary volcanicity north of the İskenderun Gulf in the eastern Mediterranean is represented by small basaltic scoria cones and flows. Approximately 115 km
2
of land area is occupied by young basalts which straddle both the main (the Karataş-Osmaniye Fault Zone) strike-slip fault system which forms the Africa-Turkey Plate boundary and the suture of the southern arm of the former Neotethys Ocean. Detailed petrological and geochemical analyses of these rocks have been carried out, with the aim of trying to understand why they have erupted in this locality. The rocks consist mainly of basanites (43–46ilica; 3.9–6.5% alkalis) and some alkali olivine basalts (45ilica; 3.8–4.2% alkalis). Both the basanites and alkali olivine basalts are porphyritic, vitrophyric and highly vesiculated with euhedral and subhedral olivine (Fo
82
-Fo
78
) phenocrysts set in a fine-grained groundmass of olivine (Fo
70
), plagioclase (An
71
-An
66
), clinopyroxene and titanomagnetite. Olivine phenocrysts contain abundant Cr-spinel and titanomagnetite inclusions. Some geochemical characteristics of these basalts indicate similarity with extension-related alkali basalts; others indicate similarity with ocean island basalt; and yet others indicate subduction-related characteristics. This complexity leads to difficulties with interpretation, especially since there is no demonstrable local extension, subduction or mantle plume activity in the vicinity.
Relationship between current measurements and sonographs of subtidal bedforms in the macrotidal Tay Estuary, Scotland
Authors: Duck Robert W. , Wewetzer Silke F. K. 
Published: April 2008

Abstract

Near bottom current measurements have been compared with sonographs revealing a variety of subtidal dune geometries at eight stations in the middle reaches of the macrotidal Tay Estuary, Scotland. At six stations, dune asymmetries did not support the tidal dominance expressed in terms of maximum or average current speeds. Determination of bottom tidal current dominance according to the length of time during which a speed of 0.5 ms
−1
was exceeded, as a proxy for the inequality of the total ebb and flood tide bedload sediment transports, provides a better, but not perfect, correlation with sonographs. Other controls on dune asymmetry and reversal are height, sediment discharge rate and bottom current velocity fluctuations. The study has shown that bedload transport processes and pathways in this relatively small (
c.
8 km
2
), dynamic part of the estuary are far more complex than previously inferred and near bed flows do not simply correspond with the surface water circulation pattern. Neither sonographs nor current data alone are adequate to gain an understanding of subtidal bedforms in such an environment.
Marine sand supply and Holocene coastal sedimentation in northern France between the Somme estuary and Belgium
Authors: Anthony Edward J. 
Published: April 2008

Abstract
From the Somme estuary to Belgium, much of the French coast is characterized by aeolian dunes, sand-choked estuaries and nearshore sand banks. The lack of sand-bearing rivers in this area and the abundance of sand in the English Channel point to the latter as the source of this important sandy accumulation. A comparison of patterns of nearshore and coastal accumulation with results from studies of the hydrodynamics and marine sand transport pathways suggests long-term drift of sand towards the French coast and the North Sea in response to tidal flows and meteorological forcing. This has occurred through sand bank migration onshore, and sand transport alongshore in a pathway hugging the French coast. From this tide-driven ‘conveyor belt’, fine sand moved onshore to form aeolian dunes, while sand of all sizes has accumulated as thick estuarine fill. This mode of Holocene coastal development emphasizes the joint action of tidal currents, storm waves and wind activity, within an overall framework of tidal dominance in this macrotidal setting.
Storm surges and erosion of coastal dunes between 1957 and 1988 near Dunkerque (France), southwestern North Sea
Authors: Vasseur Bruno , Hequette Arnaud 
Published: April 2008

Abstract
The comparison of aerial photographs of eroding coastal dunes located between Dunkerque (Northern France) and the Belgium border revealed that the retreat rate of the dune front increased between 1957 and 1988. Analyses of hourly water levels from the Dunkerque Harbour tide gauge showed an increase in the frequency of high water levels associated with storm surges during the same period. Significant wave heights that could be generated during these high water level events were computed according to a wave hindcast model and using wind data collected at Dunkerque. These analyses show an increase in storm magnitude and frequency during the last two decades of the study period, and suggest a strong relationship between dune front erosion and frequency of storm surge conditions. Since relative sea-level is rising in the southern North Sea, coastal dunes will probably be more frequently reached by storm waves in the future. Consequently, more severe coastal dune erosion may take place during the next decades, increasing the risk of flooding of coastal lowlands.
Erosion and recycling of aeolian dunes in a rapidly infilling macrotidal estuary: the Authie, Picardy, northern France
Authors: Anthony Edward J. , Dobroniak Christine 
Published: April 2008

Abstract
The Authie is a rapidly infilling macrotidal (mean estuary-mouth spring tidal range = 8.5m) estuary in Picardy, northern France, whose mouth is affected by strong tidal currents and wind waves generated in the English Channel. The estuary cuts across a major sand dune barrier and has been sourced by sand derived from offshore and alongshore, as well as from recycling of the aeolian dunes lining its north bank. Sand released by the severe erosion of these north bank dunes is temporarily stored on the beaches. A small fraction of the sand is back-cycled into the dunes via blowouts. The rest is transported towards the inner estuary where it forms longitudinal aeolian dune ridges and sand sheets that are ultimately recycled into sandy-muddy intertidal flats that develop into salt marshes. The erosion of the dunes lining the north bank of the estuary represents a morphodynamic adjustment to concentration of the tidal flux against this north bank by massive accretion and progradation of a south-bank sand platform. This erosion contributes in giving a funnel-shaped estuary mouth and probably in accommodating the tidal prism following large-scale reclamation of the inner estuary. The estuary-ward recycling of aeolian dune sand enhances overall accretion of the estuary whose ultimate fate is complete silting up in the decades to come.
Textural and geochemical evidence for the provenance of aeolian sand deposits on the Aquitaine coast, SW France
Authors: Saye Samantha E. , Pye Kenneth 
Published: April 2008

Abstract

The coastal dune system of the Aquitaine region, SW France, is the largest in Europe. At the present time the dunes are mostly stabilized by forest vegetation which is largely the product of dune stabilization schemes undertaken since the late 18th century. Much of the shoreline is currently eroding at rates of 1–2ma
−1
, which are likely to increase if predictions of accelerated sea-level rise and increased storminess are correct. The sources of the beach and dune are poorly understood, and need to be identified in order to assess the sand budgets and likely dynamic response of the dune systems to changes in environmental forcing factors. This paper presents the results of an investigation to characterize the beach and aeolian sand in the region, and to identify its origin. The dune sands were found to be texturally and compositionally similar to the Quaternary Sable de Landes which occurs landward of, and partially beneath, the coastal dune belt. The results suggest that marine, aeolian and local fluvial reworking of the Sable de Landes has provided the main source of coastal dune sand, although marine erosion of Pleistocene deposits exposed in the coastal cliffs of the Medoc has made a secondary contribution.
The use of Nuclear Magnetic Resonance Imaging (MRI) to assess impact of oil-related waste on estuarine sediments and sediment dynamics
Authors: Reeves Alison D. , Chudek John A. 
Published: April 2008

Abstract
The Marine Pollution Control Unit of the Department of Transport are at present testing the suitability of burial and landfarming of oily residues in sandy coastal environments as an alternative to landfill sites. The tendency for oil related compounds to sorb to sediments (and hence to affect their cohesiveness) has been extensively investigated, but this has not involved or permitted the ‘observation’ or measurement of advection/diffusion processes or the breakdown of these residues within sediments.
MRI, which is a multidimensional technique allowing the position of nuclei (most commonly protons) to be located within a known volume of substrate, for example sediment, provides a means of monitoring the change in position and the eventual breakdown of oil within sediments, thus offering a method of assessing the harming potential of oils in near-shore environments. Two dimensional (2D) and three dimensional (3D) MRI analysis of the movement of oil in estuarine sediments show that, using appropriate parameters, movement of the oil can be both observed and quantified. To aid quantification a sample holder fabricated from polyvinylsiloxane, an inert material visible in magnetic resonance images has been used as an internal intensity standard. The results show the great potential of MRI in studying protonated contaminants in these materials, notwithstanding the presence of paramagnetic species in estuarine sediments, which might distort the image. Sediments studied thus far have been collected from the Tay Estuary, NE Scotland.
Stratigraphic architecture, relative sea-level, and models of estuary development in southern England: new data from Southampton Water
Authors: Long A. J. , Scaife R. G. , Edwards R. J. 
Published: April 2008

Abstract

This paper presents the results of an investigation into the Holocene depositional history of Southampton Water, southern England. A three phase history of estuary development is proposed. Between
c.
7500 and 5000
bp
(8200 to 5700 cal. a
bp
), mean sea-level rose rapidly from
c.
−9m to −4 m
od
. During this interval thin basal peats which developed in present outer estuary locations were inundated and the area of intertidal and subtidal environments within the estuary expanded. Relative sea-level (RSL) rise began to slow between 5000 and 3000
bp
(5700 and 3200 cal. a
bp
) and a phase of saltmarsh and freshwater peat accumulation occurred. In this interval freshwater peat-forming communities extended outwards and seawards across former saltmarsh and mudflat environments and caused a reduction in the extent of the intertidal area within the estuary. During the late Holocene there was a switch to renewed minerogenic sedimentation as most of the freshwater coastal wetlands of Southampton Water were inundated. This tripartite model is broadly applicable to the Thames and the Severn estuaries, suggesting that regional processes have controlled their macroscale evolution. RSL change and variations in sediment supply emerge as key controls during the first two phases of estuary development. The late Holocene demise of the estuary wetlands probably reflects a propensity for increased sediment reworking and unfavourable conditions for the accumulation and preservation of organogenic deposits due to reduced rates of long-term RSL and watertable rise.
Coastal development and human activities in NW Germany
Authors: Petzelberger Bianka E. M. 
Published: April 2008

Abstract

The flat coastal region of NW Germany is constructed of siliciclastic and organic sediments which were deposited during the Holocene sea level rise. By 7500
bp
the marine transgression had reached the present coastal area which is proved by brackish-marine sediments. Nearly coinciding with this there was an evident deceleration of the sea-level rise. A reconstruction of the coast-line for the last 2000 years on the basis of the sediment and settlement distribution shows that the coast remained more or less in the same position during this period of time. However this does not apply to certain regions. Thus, bays which existed around the time 0
ad
, gradually became mainland. In other areas late Medieval and early Modern storm floods were responsible for great losses of mainland, such as the Jade Bay. These losses of mainland are especially noteworthy, because these area had been protected with dykes. Until the beginning of dyke building the settlers of the flat coastal region raised their dwelling areas artificially and built dwelling mounds (so-called Wurten) in order to be protected against flooding. By doing this men reacted to the influences of their environment, but by building dykes they started to shape their environment actively.
Intertidal peats and the archaeology of coastal change in the Severn Estuary, Bristol Channel and Pembrokeshire
Authors: Bell Martin 
Published: April 2008

Abstract

Dates for the beginning and end of intertidal and coastal peat formation are reviewed in the Severn Estuary, Bristol Channel and Pembrokeshire. Peat formation at many sites started between
c.
6000–4000 Cal
bc
and in the Severn Estuary continued until
c.
200 Cal
bc
. Archaeological evidence is concentrated at two main stages within the coastal sequences. Throughout the area Mesolithic sites underlie the earliest peat and relate to coastal exploitation just prior to the transgression represented by peat formation. During the main period of peat formation from the later Mesolithic to the early Bronze Age there is only small-scale human activity within the coastal peats. A second episode of concentrated human activity is confined to the Severn Estuary and occurs in the middle Bronze Age and Iron Age. Round and rectangular buildings and trackways are associated with the initial stages of marine transgressions which led to the burial of a coastal bog by minerogenic silts. A transgression in the middle Bronze Age
c.
1400 Cal
bc
was followed by a regression phase, the main period of human activity at Goldcliff, this ended with a widespread transgression centred on in the third century
bc
. The factors which attracted human activity at particular stages within the coastal sequence are considered, as is the relative visibility of human activity during each sedimentary stage. The contribution which archaeological evidence, particularly dendrochronological dating of wooden structures, can make to the dating of coastal change is emphasized.
Basal ice formation and deformation in central Greenland: a review of existing and new ice core data
Authors: Souchez R. , Vandenschrick G. , Lorrain R. , Tison J.-L. 
Published: April 2008

Abstract
In this paper we review, and supplement, existing data to investigate the character, origin and deformation of the basal silty ice of the centre of the Greenland ice sheet as revealed in the Dye3, GRIP and GISP2 cores.

A major process of basal silty ice formation in the central part of Greenland is incorporation of relict non-glacial ice at the base of the ice sheet during its development. The evidence for this can be found in a stable isotope composition study, both in δD and δ
18
O, in a total gas content and gas composition study, in a comparison of the dielectric conductivity profile and chemical profiles. Ice crystallographic investigations and the study of the isotopic compositions in Nd, Sr and Pb of the mineral particles embedded in the silty ice help to clarify the situation.

The processes proposed to explain the stacked sequence developed in the basal silty ice of these central areas are folding resulting in the interbedding of silty ice and glacial ice, and flow-induced mixing related to circular motion of ice in bedrock depressions with flow separation accompanied by some entrainment of the underlying ice.
Ice crystallographic evolution at a temperate glacier: Glacier de Tsanfleuron, Switzerland
Authors: Tison Jean-Louis , Hubbard Bryn 
Published: April 2008

Abstract
Ice crystallographic measurements have been made on eight cores retrieved from temperate Glacier de Tsanfleuron, Switzerland. Cores are aligned approximately along a flow-parallel transect, allowing a stratigraphic model of crystallographic evolution at the glacier to be constructed.

Results indicate the presence of four crystallographic units at the glacier. Unit 1 composed of homogeneous, fine-grained ice with a uniform fabric, is located within
c.
20 m of the ice surface in the accumulation area of the glacier. Crystal growth within this unit occurs in the absence of significant stresses, and its rate is closely described by an Arrheniustype relationship. Unit 2 ice, characterized by the local development of coarser crystals, forms after some decades of Arrhenius growth, marking the initial influence of processes of dynamic recrystallisation. Unit 3 ice, characterized by an abrupt increase in minimum crystal size, occurs at a depth of
c.
33 m throughout the glacier. In the accumulation area, this increase coincides with the first evidence of systematic fabric enhancement, interpreted in terms of dynamic recrystallisation. Unit 4 ice, characterized by large, interlocking grains with a multi-modal girdle fabric, develops within
c.
10 m of the glacier bed. Here, the measured minimum crystal size is consistent with a steady-state balance between Arrhenius processes of grain growth and strain-related processes of grain-size reduction. These changes are interpreted in terms of the effects of intense, continuous deformation in this basal zone.
The effect of H
2
SO
4
on the stress exponent in ice single crystals
Authors: Baker I. , Trickett Y. L. , Pradhan P. M. S. 
Published: April 2008

Abstract

Sulphuric acid is a naturally occurring contaminant in ice. Recently, it was demonstrated that, during compression tests at −20°C and a strain rate of 1 × 10
−5
s
−1
, as little as 0.1 ppm H
2
SO
4
reduced both the peak strength and the subsequent flow stress of ice single crystals that deform primarily by basal slip. In the present work, compression tests were performed at −20°C at a variety of strain rates on both undoped ice single crystals and ice single-crystals containing 6.8 ppm sulphuric acid of various orientations again deforming primarily by basal slip. The results show that sulphuric acid dramatically decreases both the peak stress and the subsequent flow stress of ice single crystals at all strain rates. In contrast, the stress exponent was determined to be 1.89–1.97 and was unaffected by the dopant. This value is similar to values found by previous workers for undoped ice crystals.
Structural styles and deformation fields in glaciers: a review
Authors: Hambrey Michael J. , Lawson Wendy 
Published: April 2008

Abstract
Early structural glaciological research focused on analysis of particular structures or on mapping of structural features at particular glaciers. More recently, glacier structures have been interpreted in the context of deformation rates and histories measured or estimated using a range of techniques. These measurements indicate that glacier ice experiences complex, polyphase deformation histories that can include a wide range of types, rates and orientations of strain. Deformation styles in glacier ice resemble those in rocks, but occur at a much faster rate, allowing direct measurements to be undertaken, and providing potentially useful models of rock deformation. Structural analysis in the context of measured deformation shows that a wide range of structures (e.g. folds, foliations, boudins, shear zones, crevasses and faults) develop in response to complex strain environments, but strain does not necessarily result in the generation of structures. In the future, three-dimensional numerical modelling may be able to interpret and predict deformation histories and structural development.
Experimental work on the effect of pre-existing anisotropy on fabric development in glaciers
Authors: Wilson Christopher J. L. 
Published: April 2008

Abstract

Localization of deformation in ice is known to be important at all scales in deforming glaciers. However, relatively little is known of the significance of shear localization and the influence of fabric development in anisotropic ice at microscopic scales (<mm-cm). In this experimental study, the effect of initial
c
-axis preferred orientation and the inclination of the primary layering in anisotropic ice masses, during both plane strain-compression and combined simple shear-compression, have been examined. A series of creep tests in the temperature range of −5 to −1°C over a range of shortening strains varying from 10 to 40% and compressive stresses ranging from 0 to 0.7 MPa have been undertaken. Significant variations in the strain rate and microstructural development have been observed in the plane strain-compression experiments that reflects the varying orientations of the anisotropy and its relationship to easy-glide directions in the ice mass. In the unconfined combined compression and shear experiments minimum shear stress rates vary between the variously oriented anisotropic ice masses and deviate from the normal power flow law for isotropic ice. Where annealing occurs, such ice masses preserve the pre-existing
c
-axis fabric and hence may reflect a contribution from both the recrystallized and inherited ice components.