bluuebunny/crossref_metadata_2025_split huggingface dataset:
Holocene development of the east bank of the Gironde Estuary: geoarchaeological investigation of the Saint Ciers-sur-Gironde marsh
Authors: Mellalieu Simeon J. , Massé Laurent , Coquillas Didier , Alfonso Stéphanie , Tastet Jean-Pierre 
Published: April 2008

Abstract
The nature of postglacial sea-level change and sediment infilling of the Gironde Estuary, SW France, has previously been reconstructed using a sequence stratigraphic model. This paper examines specifically the development of the St Ciers-sur-Gironde marsh during the late Holocene. The study area forms the largest expanse of coastal wetlands on the east bank of the Gironde. A geoarchaeological approach is used incorporating borehole survey, sedimentological and diatom analysis, radiocarbon dating, archaeological, documentary and cartographic evidence, which aims to test and refine the previous model of estuarine development.

The later Holocene sequence is characterized by alternating clay-silt and peat facies. Diatom evidence indicates that clay-silt units represent sedimentation under marine-brackish estuarine conditions in intertidal mudflat, and potentially saltmarsh, environments. The palaeoenvironmental conditions represented by the main upper peat unit, dated to 5600-2600
bp
, are currently unknown due to the absence of diatom evidence from these levels. Within an overlying trend of rising relative sea-level over the past 6000 years, 3 negative sea-level tendencies appear to have occurred. There is insufficient resolution in the present data set to determine the exact nature of each or their duration.
Holocene coastal change in the north of the Isle of Man: stratigraphy, palaeoenvironment and archaeological evidence
Authors: Gonzalez Silvia , Innes Jim , Huddart David , Davey Peter , Plater Andrew 
Published: April 2008

Abstract

New multidisciplinary work at Phurt in the north of the Isle of Man using stratigraphy, radiocarbon dating, pollen, diatoms, foraminifera and archaeology has reevaluated the sedimentological and archaeological sequence located in a series of basins containing organic peats, silts and sands at the south end of the Flandrian Ayres raised beach succession. From this work it is clear that all the Mesolithic finds from the beach have been reworked and are not significant in terms of human occupation in this area and there is no evidence for human modification of the Mesolithic vegetation from Phurt. The radiocarbon dates for the middle peat fit into the Neolithic phase and although all the
in situ
artifacts are from layers above the peat from a sandy palaeosol, these layers are likely to have been deposited rapidly after the peat formation. Although the artifacts are Middle Neolithic in typology it is considered that the dates from the peat are not inconsistent with the archaeological dating framework.

The pollen indicates an early woodland phase but there are indicators of the close proximity of the sea from coastal pollen taxa, foram test linings in the upper peat layer and diatoms. In the middle peat tree pollen was much less frequent, there was a wide range of open ground herb taxa, mainly of freshwater type but again there were salt marsh taxa present, indicating the close proximity of the sea. In the upper organic horizon and the burnt mound profiles the lack of coastal pollen must indicate a relative sea-level drop. The depositional environment envisaged to account for the litho- and pollen stratigraphy in these small basins is predominantly a freshwater lake behind shingle bars, with the close proximity to seaward of a saltmarsh. On occasions there must have been brackish water in these lagoons and a marine connection through the shingle barrier based on the diatom evidence, which is similar to the interpretation at nearby Lough Cranstal. This is in contrast with the Liverpool Bay sequences where there is evidence for several marine transgressions, but in both areas the coastal or near coastal environments indicate much well preserved evidence for Neolithic and Bronze Age occupation and vegetational alteration by these populations.
Doggerland: the cultural dynamics of a shifting coastline
Authors: Coles Bryony J. 
Published: April 2008

Abstract
The landmass now covered by the North Sea, here referred to as Doggerland, has had an important but neglected influence on the course of prehistory in northwestern Europe. The physical character of Doggerland in the Late Glacial and earlier Holocene is assessed, together with its re-colonization by humans after the Last Glacial Maximum. The development of a maritime-based society along the northern coast of Doggerland is postulated, and it is argued that the coastal inhabitants, with their specialized adaptation to this zone, will have moved with the coast as relative sea-levels changed. The interactions of coastal and inland populations are considered, including the probable influence of the coastal groups in delaying the spread of farming into the region.
Development-led archaeology in coastal environments: investigations at Queenborough, Motney Hill and Gravesend in Kent, UK
Authors: Firth Antony 
Published: April 2008

Abstract
This paper reviews a series of investigations undertaken by Wessex Archaeology in North Kent in advance of major construction projects. Three sites have been investigated on areas of former saltmarsh at Queenborough, Motney Hill and Gravesend. All three sites currently contain wastewater treatment works (WTW) which are being enhanced in order to meet new water quality standards, involving the construction of new buildings on dense grids of piles driven through the alluvium to more solid strata up to 15 m below ground surface. The paper discusses each investigation in terms of the archaeological and geotechnical background, the evaluation and mitigation strategy adopted, and the contribution that the results may make to our understanding of human activity on the North Kent coast over the past 10 000 years. The paper also looks ahead to development-led investigations at other coastal locations, to show how such work can make a direct contribution to geoarchaeological research while reconciling the objectives of construction and conservation.
Folding in the Johnsons Glacier, Livingston Island, Antarctica
Authors: Ximenis L. , Calvet J. , Garcia D. , Casas J. M. , Sàbat F. 
Published: April 2008

Abstract

An active fold system revealed by interbedded tephra layers is visible on the ablation surface of Johnsons Glacier (Livingston Island, South Shetland Islands, Antarctica). Johnsons Glacier is a cirque-shaped glacier of 5 km
2
area located in a temperate ice cap. Converging flow-lines as a consequence of the reducing channel section extend from ice divides and terminate in a calving ice-cliff. Recent tephra layers from the volcano on Deception Island constitute excellent markers of the internal structure of the glacier and, when dated, provide valuable information about deformation kinematics.

Detailed field mapping of the clearly visible tephra markers revealed several folded layers that define a set of folds with sub-horizontal and fan-distributed axes being sub-parallel to the converging flow-lines. Folds become tighter towards the centre of the channel, where a cylindrical anticline is clearly exposed. Related deformational structures, comprising minor folds, foliations, thrust faults and crevasses, are observed in the ablation area. Strain-rates reflect extensional flow and higher deformation values where maximum confluence occurs.
We examine how the occurrence of this structure results from the transverse shortening in response to the reducing channel section and the consequent confluence of ice masses, increase in differential flow-rates between the centre of the glacier and the margins, and the development of passive folding processes.
The Pasterze glacier, Austria: an analogue of an extensional allochthon
Authors: Herbst Paul , Neubauer Franz 
Published: April 2008

Abstract
Structures of the Pasterze glacier (Austria) have been studied in detail and interpreted as representing a natural model of an extensional allochthon formed on top of an orogenic wedge, and also a model for raft tectonics at passive continental margins. Structures of the lower, ablation-controlled portion of the glacier, including ductile structures at the base, are forming close to the melting point of ice, with predominantly brittle structures close to the surface of the glacier. Formation of these structures results from self-weight, gravity-driven spreading, similar to extensional allochthons.
S-planes are common and clearly related to three individual flow units. They show a typical, spoon-like arrangement. These three flow units are bordered by centimetre- to decimetre-wide shear zones which also include shear folds. Brittle structures include ice-mineralized tension gashes, thrust and normal faults, and hybrid, shear-extensional fractures. Together, these structures show that glacial flow is more rapid in middle to upper sectors of the glacier than along the lateral, and lower margins. The coherent upper sheet is behaving in a brittle manner and is elongating slightly along the flow direction by tensional deformation.
The distribution of structures allows three structural domains within the lower, ablation-controlled sector of the glacier to be distinguished: (1) an upper sector with predominant extensional structures due to rapid flow; (2) a lower sector with ductile and brittle thrust faults, penetrating from the ground and dipping strictly opposite to the local flow direction; (3) a few normal faults at the terminus that developed by rapid melting along the steep lower frontal margin of the glacier. These three structural domains are also found within extensional allochthons as exemplified by the Neogene Alpine-Carpathian system where a huge allochthon, partly driven by gravity, extruded from the Eastern Alps towards the Carpathian arc. Three similar structural domains are also found in recent analogue models and field examples of passive continental margins.
Behaviour of subglacial sediment and basal ice in a cold glacier
Authors: Fitzsimons Sean J. , Lorrain Regi D. , Vandergoes Marcus J. 
Published: April 2008

Abstract
Tunnels in glaciers offer unique opportunities for examining basal processes. At Suess Glacier in the Taylor Valley, Antarctica, a 25 m tunnel excavated into the bed of the glacier provides access to a 3.2m thick basal zone and the ice-substrate contact. Measurements of ice velocity over two years together with glaciotectonic structures show that there are distinct strain concentrations, a sliding interface and thin shear zones or shear planes within the basal ice. Comparison of ice composition, debris concentrations and the shear strength of basal ice samples suggest that strength is controlled by ice chemistry and debris concentration. The highest strain rates occur in fine-grained amber ice with solute concentrations higher than adjacent ice. Sliding occurs at the base of the ice that experiences the highest strain rates. The substrate and blocks of the substrate within basal ice are characterized by brittle and slow ductile deformation whereas ice with low debris concentrations behaves in a ductile manner. The range of structures observed in the basal ice suggests that deformation occurs in a self-enhancing system. As debris begins to deform, debris and ice are mixed resulting in decreased debris concentrations. Subsequent deformation becomes more rapid and increasingly ductile as the debris and sedimentary structures within the debris are attenuated by glacier flow. The structural complexity and thickness of the resulting basal ice are considerably greater than previous descriptions of cold glaciers and demonstrate that the glacier is or was closely coupled to its bed.
Molecular phylogeny of the Bivalvia inferred from 18S rDNA sequences with particular reference to the Pteriomorphia
Authors: Steiner Gerhard , Hammer Sabine 
Published: April 2008

Abstract
The classification of the Pteriomorphia, a major division of the Bivalvia with Ordovician origins, is controversial both among palaeontologists and neontologists. To elucidate phylogenetic relationships new near-complete 18S rDNA sequences of 26 Pteriomorphia, three Protobranchia, three Heterodonta, one Anomalodesmata and three Scaphopoda were obtained, aligned with 71 other published molluscan sequences, and analysed with parsimony, maximum likelihood and spectral analysis. Although Bivalvia appear diphyletic due to heterogeneity of substitution rates among lineages, monophyly of Protobranchia, Heteroconchia and Pteriomorphia is supported. The heteroconch Lucinida, Myoida and Venerida are not monophyletic, and Anomalodesmata arise from within Heteroconchia. The basal nodes of Pteriomorphia have little support but two major clades, [Pinnoidea (Ostreoidea + Pterioidea)] and [(Anomioidea + Plicatuloidea) + (Limoidea + Pectinoidea)], are resolved with more confidence. The strongly supported clade of Anomioidea + Plicatuloidea, the separation of Pinnoidea from Pterioidea and most of the intrafamiliar relationships are not in accordance with morphological classifications. Combining these results with selected morphological characters, a phylogenetic hypothesis is proposed showing Mytiloidea and Arcoidea as the basal pteriomorph groups, the latter giving rise to the clade uniting the pinnoid-ostreoid-pterioid and the anomioid-limoid-pectinoid lines.
Prodigious polyphyly in imperilled freshwater pearly-mussels (Bivalvia: Unionidae): a phylogenetic test of species and generic designations
Authors: Lydeard Charles , Minton Russell L. , Williams James D. 
Published: April 2008

Abstract

Unionid bivalves or freshwater pearly-mussels (Unionoidea: Unionidae) serve as an exemplary system for examining many of the problems facing systematists and conservation biologists today. Most of the species and genera were described in the late 1800s and early 1900s, but few phylogenetic studies have been conducted to test conventional views of species and classification. Pearly-mussels of Gulf Coastal drainages of the southeastern United States from the Escambia (southern Alabama to Florida) to the Suwannee Rivers (Florida) are a unique fauna comprised of approximately 100 species, with about 30 endemic to the region. In this study, mitochondrial cytochrome c oxidase subunit I and 16S rRNA gene sequences were used to test the monophyly and to estimate evolutionary relationships of five unionid species representing three different genera. The molecular phylogenies depict all three genera as polyphyletic. The prodigious polyphyly exhibited within unionids is due to incorrect notions of homology and false assumptions about missing anatomical data. In contrast, the molecular phylogeny provides evidence to support the recognition of all five unionid species as distinct evolutionary entities. Furthermore, molecular genealogical evidence supports the elevation of
Quincuncina infucata
(Conrad) of the Suwannee River to species level, for which
Q. kleiniana
(Lea) is available.
Early Cretaceous giant bivalves from seep-related limestone mounds, Wollaston Forland, Northeast Greenland
Authors: Kelly Simon R. A. , Blanc Eric , Price Simon P. , Whitham Andrew G. 
Published: April 2008

Abstract

Anomalous mound-forming limestones, here termed the Kuhnpasset Beds, occur within Late Barremian (Early Cretaceous) mudstones on Wollaston Forland, Northeast Greenland. The normal mudstones contain a sparse fauna of small nuculoids, arcoids and inoceramids; by contrast, the mounds contain an unusual faunal assembage, dominated by large bivalves. These include an abundant lucinid,
Cryptolucina kuhnpassetensis
sp. nov., and, less commonly,
Solemya
, both known seep-associated genera. Locally, a large modiomorphid,
Caspiconcha whithami
gen. et sp. nov., is common and reaches > 300 mm in length and has a shell up to 28 mm thick. Also, the wood-boring bivalve
Turnus
is abundant in driftwood. Gastropods are rare, but the associated cephalopod fauna includes ammonites, belemnites, nautiloids and a remarkable large orthoconic phragmocone. The form of the mounds with calcite-cemented tube systems, associated laminated calcite crusts and void fills, together with the fauna, is analogous to those of methane-based cold-seep complexes. However, preliminary studies indicate that much of the original aragonitic shell is now replaced by silica. This precluded conclusive geochemical studies based on the shells themselves. It is believed that the mounds formed on the seafloor in a mid- to outer shelf situation at the end of a period of extensional rifting on the eastern Greenland passive Atlantic margin. The vents occur near the footwall crest of a tilted fault block. The underlying faults may have provided routes or influenced direction of movement for nutrient migration. Source rocks were probably the Late Jurassic black shales from depths of < 600–1200 m. If methane was being generated, it was probably forming by shallow-depth organic breakdown rather than by thermogenic processes, which require greater burial.
The function of pallial eyes within the Pectinidae, with a description of those present in
Patinopecten yessoensis
Authors: Morton Brian 
Published: April 2008

Abstract

The structure of the pallial, ectopic eye of
Patinopecten yessoensis
is described and shown to be of the typical pectinid form, located on the middle mantle fold. The cornea is, however, a tall epithelium and, with the lens, forms a Cartesian oval, unlike the lens alone in other pectinids which functions to counter spherical aberration. The basal cell layer beneath the retina and argentea is poorly pigmented, although this may be countered by the fact that the optic tentacle epithelium itself is apically heavily pigmented.

It is generally assumed that pectinid pallial eyes, being able to perceive a moving image, are used to warn of vicinal predators, resulting in swimming. However, this does not seem to be the case; although crabs and starfish, in particular, are known predators of scallops, which respond by swimming to the latter, they do so (usually) on receipt of mechanical and chemical stimuli, not visual. Some scallop species live in seagrass beds and there is evidence that these may afford protection. Scallops are visually attracted to the waving fronds.

Scallops may also make relocation movements and, in more specialized taxa, e.g. species of
Amusium
, can swim for several metres. The visual sense of scallops is poorly understood and although pallial eyes may have developed early in the ancestry of the Pectinidae, as an antipredation sense organ, they may, in the descendants, now have a different, but perhaps related, function, although what this is, is unknown. Pectinid pallial eyes may improve the efficiency of photon capture in low light intensity subtidal habitats but for what purpose is unclear, since even if they are functioning as optical ‘burglar alarms’, what could they see in such a situation, especially as there is no brain to formulate an image?
Functional anatomy of the digestive system of
Neoteredo reynei
(Bartsch, 1920) and
Psiloteredo healdi
(Bartsch, 1931) (Bivalvia: Teredinidae)
Authors: Lopes Sônia G. B. C. , Domaneschi Osmar , De Moraes Daniela T. , Morita Marisa , Meserani Georgeana De L. C. 
Published: April 2008

Abstract

Studies on the digestive system of the Teredinidae are useful for a better understanding of the evolution of these bivalves in relation to the xylophagous habit.
Neoteredo reynei
and
Psiloteredo healdi
, two common species in Brazilian mangroves, have evolved differently in their methods to use wood as food, despite the similarities in the anatomy and functioning of their globular type II stomachs.
N. reynei
is predominantly xylophagous throughout its life, while
P. healdi
, despite its predominant suspension-feeding habit, uses wood more efficiently as the animal grows older. The outstanding differences that allow these conclusions are the large size of the appendix and anal canal in
N. reynei
, always conspicuous and packed with wood, and the small appendix of
P. healdi
, which increases in size with age. Based on anatomical data and revision of the literature, it is suggested that in both species the appendix, and also the anal canal in
N. reynei
, is of primary importance in the digestion of wood and absorption of nutrients, counterbalancing the reduced specialized digestive diverticula.
Evolutionary trajectories of a redundant feature: lessons from bivalve gill abfrontal cilia and mucocyte distributions
Authors: Beninger Peter G. , Dufour Suzanne C. 
Published: April 2008

Abstract
Recent data on the distributions of cilia and mucocytes on the bivalve gill abfrontal surface are analysed with respect to evolutionary relationships of the principal autobranch gill types. From the primitive function as a mucociliary cleaning surface in the protobranchs, two evolutionary trajectories are evident: (1) progressive reduction of both cilia and mucocytes with resultant loss of surface function, seen in the homorhabdic filibranchs studied; (2) reduction of cilia but retention or increase in acid mucopolysaccharide-secreting (AMPS) mucocyte density in the eulamellibranchs, corresponding to the assumption of a new function, probably in the reduction of frictional resistance to flow in the water canals. Heterorhabdic gill abfrontal surfaces present a mixture of these characteristics: reduction of cilia and mucocytes on the ordinary filaments, and retention of both on the principal filaments. The retention of AMPS mucocytes on the abfrontal surface of the pseudolamellibranchs may be related to the degree of interlamellar fusion, reducing frictional resistance to water flow as in the eulamellibranchs. The gill abfrontal surface thus constitutes an excellent candidate for the study of the different evolutionary options and trajectories of a redundant feature.
Morphodynamics of
Bryopa
and the evolution of clavagellids
Authors: Savazzi Enrico 
Published: April 2008

Abstract

Typical clavagellids are either tube dwellers in soft sediments or facultative semiendolithic borers.
Bryopa
deviates from this pattern by being fully and obligatorily endolithic. The left valve in
Bryopa
is permanently attached to the wall of the borehole. In spite of this, the bivalve migrates forwards within the substrate throughout growth. These seemingly incompatible feats are achieved by continuously elongating the shell in the anterior direction and sliding forwards the soft parts, hinge and right valve within the shell. While the left valve becomes elongated, the posterior region of the right valve is continuously destroyed by resorption. The resulting strongly inequivalve condition is unique among clavagellids, as well as endolithic bivalves.

In the lack of direct evidence, the evolution of clavagellids from less specialized stocks remains open to alternative hypotheses. Probable parallel evolution within the clavagellid stock further complicates the problem. Evolution of tube-dwelling clavagellids directly from burrowing ancestors is as likely as their evolution from a hypothetical, endolithic protoclavagellid. In the latter case, however,
B. lata
is probably too specialized to reflect the adaptations of such an ancestor.