bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulated aeolian abrasion of Pannonian sands and its implications for the origins of Hungarian loess
Authors: Smith B. J. , Wright J. S. , Whalley W. B.
Published: February 2007

Quartz sand from southern Hungary was agitated for 128 hours in an abrasion chamber using a constant airstream. The fines produced by abrasion were collected from the exhaust air using an electrostatic precipitator. Analysis of the fines at set intervals by Coulter Counter show particle size distributions after 16 hours with > 50 per cent in the 20‐60 μm range (the size range normally associated with loess deposits). Results demonstrate the feasibility of a local, abrasion derived contribution to Hungarian loess.
Alluvial cutoffs as indicators of former channel conditions
Authors: Erskine Wayne , McFadden Christopher , Bishop Paul
Published: February 2007

Although alluvial cutoffs record accurately the geometry, bedforms, and bed material of the channel when last active, few attempts have been made to use cutoffs in studies of channel changes. A detailed record of historical channel changes on the lower Hunter River in southeastern Australia has shown that this channel responds to naturally alternating periods of high and low flood activity, called flood‐ and drought‐dominated regimes respectively. Sinuosity decreased from 3·84 in 1870, to 2·66 in 1893 and to 1·38 in 1970 through the development of eight cutoffs. The channel also aggraded with medium sand burying the former bed material of mixed mud, coarse sand, and gravel. Channel straightening was a response to increased flood frequencies during the flood‐dominated regimes of the late 19th and 20th centuries, combined with localized river engineering works and increased sand load.

Detailed stratigraphic studies were carried out on three neck cutoffs and one chute cutoff which were abandoned in 1890, 1950, 1952, and 1956. A comparison of former and present bed elevations and bed material size showed similar trends to those determined by the historical record, confirming the reliability of cutoffs as indicators of former channel conditions.

The sedimentary infills of the cutoffs are not uniformly fine grained as recorded previously in the literature. Relatively thin, fine‐grained fills were deposited during the drought‐dominated regime of the first half of this century but thick, coarser‐grained fills were deposited after 1949 during the flood‐dominated regime. All fills fine upwards. Cutoff infills provide a record of changing flood activity and sediment loads.
Analysis of spatial relationships among geomorphic, petrographic and structural characteristics of the dartmoor tors
Authors: Ehlen Judy
Published: February 2007

The granite tors of Dartmoor are characterized by using the regional spatial patterns of 21 geomorphic, petrographic, and structural variables. The data were derived from topographic maps, field measurement, and laboratory analysis of rock samples collected in the field. Identification of spatial patterns and comparison of patterns between variables were made on contour maps generated from the data using ARC/INFO. Three tor types—summit tors, valleyside tors, and spur tors—are semiquantitatively characterized using these data and procedures.

The three types of tors are distinguished with respect to variations in relative relief, joint spacing and joint type, rock texture, grain size, and composition. Summit tors have the highest relative relief (mean: 125·7 m), contain the most potassium feldspar (>30 per cent), and have the most widely‐spaced primary vertical (>300 cm) and secondary horizontal joints (> 10 cm). The rocks are the most megacrystic (> 15 per cent) and the coarsest grained. Plagioclase is also abundant in summit tors. Valleyside tors have the lowest relative relief (mean: 72·9 m) and the most widely‐spaced horizontal joints (primary, 60‐200 cm; secondary, > 10 cm). Grain size, vertical joint spacing, and quartz and potassium feldspar abundances are intermediate. The shapes of valleyside tors are controlled by horizontal joints and the rocks are either very feebly magcrystic or equigranular in texture. Spur tors have intermediate relative relief (mean: 115·4 m), the narrowest joint spacing (vertical joints, < 200 cm, 50‐75 cm; horizontal joints <60 cm, < 10 cm) and the finest grain. In addition, the rocks are feebly magacrystic.
Geomorphic activity of rabbits on a coastal sand dune, De Blink dunes, the Netherlands
Authors: Rutin J.
Published: February 2007

A study of the erosion rate and the stability of sandy slopes was conducted on an eastern arm of a parabolic coastal sand dune, De Blink, central Netherlands. The contribution of rabbits to these processes was found to depend on two types of activity; the building of caves and sand mounds of up to 1·5 m2 in area; and the digging of shallow burrows, whereby amounts of sand up to 1 kg per burrow were excavated. The burrowing activity was found over the whole dune, while cave holes were dug mainly on the northern slope. The total amount of sand actually transported on the dune due to this activity is not clear yet, but their influence on the development of stepped slopes is well established.
Long‐term landscape evolution in Australia
Authors: Gale Stephen J.
Published: February 2007

The main features of the Australian physical landscape are of the order of 107‐108 years old. This contradicts the widely held view that little of the Earth's topography predates the Quaternary and that erosion cycles are carried to planation within tens of millions of years. Much of the Australian landscape must have developed over similar timescales to that of the tectonic evolution of the continent itself. The study of the geomorphology of such ancient terrains may therefore be seriously deficient unless it is considered within the context of continental‐scale tectonic development. Application of this approach shows that there are strong links between the geomorphology of Australia and plate movements, ocean spreading, plate convergence, tectonostratigraphic terranes, orogenesis and epeirogenesis.

The most important factor contributing to the survival of ancient landscapes in Australia is the low rate of denudation which the continent has experienced during the Mesozoic and Cenozoic. This is largely a consequence of orogenic stability, although the absence of significant Quaternary glaciation may also be of importance. However, in order for landforms to have survived over such timespans, denudation must not only have been low, but must also have been highly localized over space and time. This has been the case both on a regional scale, with long‐term denudation rates of 0‐2 m Ma−1 in central Australia contrasting with higher rates along the continental margins, and on a local scale, with denudation confined to valleys, leaving divides and interfluves almost unscathed.
Geomorphological development of the eastern margin of the Australian Craton
Authors: Twidale C. R. , Campbell E. M.
Published: February 2007

The denudation chronologies of five uplands of contrasting geological structure located at the eastern margin of the Australian Craton are examined. They are the Isa Highlands, MacDonnell Ranges and Flinders Ranges (fold mountains, orogenic setting); the Arcoona Plateau (dissected plateau, platform setting); and the Gawler Ranges (massif of old silicic volcanics, cratonic setting). In each, surfaces of Mesozoic age, many of them exhumed and of pre‐Cretaceous age, are preserved. Each also appears to have been uplifted recurrently. Each was either overwhelmed or bordered by the Early Cretaceous (Neocomian‐Aptian) sea.

Tectonism associated with the break‐up of Gondwana probably allowed this important marine transgression. Thereafter, thalassostatic and erosional/depositional isostatic responses have maintained the uplands as uplands and the intervening basins as negative topographic and structural units; the pattern of topography has been constant for the last 60–100 Ma.
Problems in automated recognition of valley features from digital elevation models and a new method toward their resolution
Authors: Tribe Andrea
Published: February 2007

Valley recognition methods given in the literature fail to produce valley networks suitable for locating valley heads for one of two main reasons: (a) they are based on the concept of [higher than] or (b) they are based on contributing area thresholds. In this paper a new method for recognizing valley bottoms is presented. This is based on two improvements of Carroll's (1983) method, and produces a network that reflects the topography well. The network is used to locate valley heads. Once located, the valley heads are delineated using criteria suggested by geomorphologists and hydrologists. The resultant valley heads are generally well recognized although two problems are evident: (a) there are a number of commission errors; and (b) the valley heads recognized by the method are too small.
Relationship between discharge, velocity and flow area for rills eroding loose, non‐layered materials
Authors: Govers Gerard
Published: February 2007

A relationship between discharge, flow velocity and flow area in rills is established using data from four field and laboratory studies. The proposed relationship is shown to predict successfully flow velocities measured in six other studies. Although slopes range from 0.035 to 0.45 and soil materials range from stony sands over silt loams to vertisols, mean flow velocity can be well predicted from discharge alone. Thus, there is no important influence of slope and/or soil material characteristics on flow velocities in rills. The proposed relationship may be used to improve performance of deterministic flow routing models when applied to rilled catchments. Furthermore, it allows the calculation of unit stream power, which has been shown to be related to the transporting capacity of overland flow, in terms of slope and discharge.
Floodplain storage of mine tailings in the belle fourche river system: A sediment budget approach
Authors: Marron Donna C.
Published: February 2007

Arsenic‐contaminated mine tailings that were discharged into Whitewood Creek at Lead, South Dakota, from 1876 to 1978, were deposited along the floodplains of Whitewood Creek and the Belle Fourche River. The resulting arsenic‐contaminated floodplain deposit consists mostly of overbank sediments and filled abandoned meanders along White‐wood Creek, and overbank and point‐bar sediments along the Belle Fourche River. Arsenic concentrations of the contaminated sediments indicate the degree of dilution of mine tailings by uncontaminated alluvium.

About 13 per cent of the 110 × 106 Mg of mine tailings that were discharged at Lead were deposited along the Whitewood Creek floodplain. Deposition of mine tailings near the mouth of Whitewood Creek was augmented by an engineered structure. About 29 per cent of the mine tailings delivered by Whitewood Creek were deposited along the Belle Fourche River floodplain. About 60 per cent of that sediment is contained in overbank deposits. Deposition along a segment of the Belle Fourche River was augmented by rapid channel migration. The proportions of contaminated sediment stored along Whitewood Creek and the Belle Fourche River are consistent with sediment storage along the floodplains of perennial streams in other, similar sized watersheds.
Textural analysis and modelling of a flood deposit: River severn, U.K.
Authors: Marriott Susan
Published: February 2007

Samples of sediment collected from the Severn floodplain between Worcester and Gloucester following the severe flooding in January and February 1990, were analysed for their grain size distribution. The results show that most sand was deposited within 20 m of the channel bank, but that fine sand may contribute to flood sediment across the width of the floodplain. James' (1985) numerical model of overbank sedimentation attempts to predict the transfer of sediment to the floodplain during flooding. Geometrical and hydraulic data relating to the Severn flood are used as input for a computer program of James' (1985) model. The pattern of sediment concentrations predicted by the model was compared with that obtained from statistical analysis of the flood sediment. The patterns were found to be similar, so James' (1985) model was considered to predict in a relative sense the distribution of flood sediment.
Fault‐generated mountain fronts in the central apennines (Central Italy): Geomorphological features and seismotectonic implications
Authors: Blumetti Anna Maria , Dramis Francesco , Michetti Alessandro Maria
Published: February 2007

The morphotectonic framework of the Central Apennines is given by faulted blocks bounded by normal faults, mostly trending NW–SE, NNW–SSE and NE–SW, which cut previous compressive structures. Such a structural setting is consistent with the focal mechanisms of the earthquakes which often occur in this area.

In this paper, three lithologically different normal fault‐generated mountain fronts are analysed in order to assess the relations between their geomorphic features and active tectonics. They border the Norcia depression (Sibillini Mts, Umbria), the Amatrice–Campotosto plateau (Laga Mts, Lazio) and the Fucino basin (Marsica Mts, Abruzzi).

The Norcia depression is bounded by a N20°W trending normal fault to the east and by a parallel antithetic fault to the west. The main fault has a 1000 m throw and gives rise to a wide fault escarpment, characterized by: (1) sharp slope breaks due to low angle gravity faults; (2) important paleolandslides; and (3) several fault scarplets on the piedmont belt affecting Quaternary deposits.

The Amatrice–Campotosto plateau is delimited by the western slope of Mt Gorzano which runs along a N20°W trending normal fault having a 1500m throw. Minor parallel faults dislocate Quaternary landforms. Large‐scale massmovements also occur here.

The Fucino basin was struck by the 1915 Avezzano earthquake (I=XI MCS) which produced extensive surface faulting along two parallel NW trending normal fault escarpments on the eastern border of the basin. There is paleoseismic evidence including buried gravity graben in Late Glacial gravels and tectonic dip‐slip striations on Holocene calcitic crusts covering bedrock normal fault planes.

These data suggest that active extensional tectonics plays a major role in the slope morphogenesis of the Central Apennines and they indicate the importance of geomorphic analysis in seismic zonation of this area.
Salt weathering simulation using a single‐immersion technique
Authors: Goudie A. S.
Published: February 2007

Samples of concrete were subjected in an environmental cabinet to six different diurnal cycles of temperature and humidity change representative of desert surface conditions in the presence of a range of saturated salt solutions. The samples were not subjected to repeated immersion or continuous partial immersion as has been the case in most previous experiments. Breakdown did occur nonetheless. The two most effective cycles were one from Egypt (with a very high daytime maximum) and one from the Negev (with high nocturnal humidity conditions). Cycles with relatively modest temperature and humidity cycles were ineffective in causing debris liberation.
Identification of topographic settings conducive to landsliding from dem in Nelson county, Virginia, U.S.A.
Authors: Gao Jay
Published: February 2007

The steep terrains in the Blue Ridge Mountains of Virginia are potentially vulnerable to landsliding. Hundreds of slope failures were initiated by a severe storm in 1969 in Nelson County, Virginia. The outlines of 87 landslide scars were delineated on aerial photographs within a 28·8 km2 area. A digital elevation model (DEM) of the same area was constructed, from which three topographic variables (slope orientation, gradient and form) were derived. Overlay analyses of the landslide data and the topographic data, followed by chi‐square tests, revealed that the topographic variables studied are statistically significant to the spatial distribution of the sites disturbed by landslide paths. While the landsliding potential is low at very low and high elevations, it is found to be high in the median range of elevation. West‐, northwest‐, north‐ and northeast‐facing slopes are consistently more vulnerable to landsliding than their east‐, southeast‐, south‐ and southwest‐facing counterparts. Terrains with a gentle gradient are stable, but the potential for landslides to develop increases greatly as the terrains become steeper. The slopes with a concave cross‐section are more susceptible to landsliding than those having other shapes. Furthermore, the landsliding potential does not vary significantly with slope forms in the profile direction. It is concluded that the introduction of a DEM to this study has provided renewed insight into topographic settings conducive to landsliding which could not have been achieved otherwise.
A decade of surface change on a Namib linear dune
Authors: Livingstone Ian
Published: February 2007

Survey data from return visits to a linear dune in the Namib Desert provide information about change in dune form over a decade. The data demonstrate that, although change on these large features is slow, there is none the less considerable movement over this time‐scale. The dunes are therefore confirmed to be currently active and not Pleistocene relics.
The measurement of river bank erosion and lateral channel change: A review
Authors: Lawler D. M.
Published: February 2007

A detailed review and chronological survey is presented of the various techniques which have been used for the measurement of river bank erosion and channel change. The techniques are classified according to the time scales involved (long, intermediate and short) and each is discussed with respect to accuracy and repeatability. The methods covered include sedimentological evidence, botanical evidence, historical sources, planimetric resurvey, repeated cross‐profiling, erosion pins and terrestrial photogrammetry. Prospects for future developments are also discussed.
Analysis of riverbank instability due to toe scour and lateral erosion
Authors: Thorne Colin R. , Abt Steven R.
Published: February 2007

This paper provides instruction in the use of the computer spreadsheet to undertake the calculations necessary to apply the Osman–Thorne bank stability analysis for steep, eroding riverbanks. The guide explains how to input the necessary parameters into the LOTUS 123 spreadsheet in order to:

find the initial factor of safety of the bank with respect to slab‐type failure;

test the sensitivity of bank stability to changes in the engineering properties of the bank material;

analyse the response of bank stability to toe scour and/or lateral erosion and find the critical condition;

find the geometry of the failure surface and failure block;

analyse the response of bank stability to further toe scour and/or lateral erosion;

find the geometry of the failure surface and failure block in subsequent failures.
Erosional effects of cattle on streambanks in Tennessee, U.S.A.
Authors: Trimble Satanley W.
Published: February 2007

The geomorphological effects of cattle on streambanks in a humid region, which have consequent potential effects on water quality, are examined. Field observations suggest that cattle are important agents in causing streambanks to erode, but so many variables are involved that it is difficult to isolate the role of cattle. Instead, an empirical approach based on long‐term controlled experiment was adopted along a small perennial stream in the Central Basin of Tennessee. The results showed that uncontrolled grazing caused about six times as much gross bank erosion as occurred on the protected control stretch. However, most of this difference was due to breakdown of banks by trampling and consequent erosion, rather than by bank scour caused by removal of bank vegetation by grazing. That is, bank vegetation alone did not appear to be a primary control. A relatively inexpensive grade‐control structure reduced the gross bank erosion by about 50 per cent. The rapid destruction of streambanks observed in this study suggests that reduction of geomorphic resistance by uncontrolled stock access to streambanks has been an important factor in the stream widening that has taken place during historical time in the eastern United States.
Steady state behaviour of the black ven mudslide: The application of archival analytical photogrammetry to studies of landform change
Authors: Chandler J. H. , Brunsden D.
Published: February 2007

The concept of dynamic equilibrium has provided geomorphologists with a challenging paradigm for studying landform evolution but quantitative evidence for its existence has proved illusive, particularly for complex geomorphological systems. The authors believe that the principle has now been verified through the application of the ‘archival photogrammetric technique’ to a sequence of historical photographs spanning 50 years of process at the Black Ven mudslide complex in Dorset, U.K.

The principles and limitations of the archival photogrammetric technique are described. The method is applied to oblique and vertical aerial photographs of Black Ven at five epochs, commencing in 1946, continuing at approximately 10 year intervals until 1988. The technique is used to generate plans/contours/sections and a dense and accurate digital elevation model (DEM) of the whole site at each epoch. This is used to generate ‘DEMs of difference’ and a ‘distribution of slope angle’ which suggest that the mudslides are in equilibrium despite the removal of 200 000 m3 of sediment between 1958 and 1988. Extrapolation of the slope distribution through time suggests that the frequency of an episodic landform change model at Black Ven may be approximately 60 years.
Sediment routing analyses based on chronological changes in hillslope and riverbed morphologies
Authors: Nakamura Futoshi , Maita Hideji , Araya Tohru
Published: February 2007

Recent studies of sediment delivery and budgets in the United States indicate that upland erosion rates at a given time may not explain contemporaneous sediment yields from a drainage basin. This suggests temporal discontinuities in sediment delivery associated with hillslope and channel storage processes. Integration of sediment production, storage and transport is essential to understand sediment routing in basins. We analysed each process chronologically using aerial photographs, monitoring data of sediment movement and annual tree‐rings, and then compared estimated temporal changes in sediment production from hillslopes, floodplain disturbance areas and sediment transport in river channels. Toeslopes, floodplains and alluvial fans together contained 59 per cent of sediment eroded from uplands over the last 30 years. Monitoring results of riverbed changes showed that the volume of stored sediment on floodplains decreased exponentially with succeeding floods. The age distribution of floodplain deposits reflected the disturbance history of a river channel, and followed an exponential decrease with age. The results of this study may have important implications for sediment control plans for watersheds in steep regions.
Rapid formation of rock varnish and other rock coatings on slag deposits near Fontana, California
Authors: Dorn Ronald I. , Meek Norman
Published: February 2007

Manganiferous rock varnish, silica glaze and iron skins have formed on 20‐ to 40‐year‐old slag piles near Fontana, southern California. Rapid rock‐varnish formation is associated with an unidentified cocci bacterium that grows rapidly in culturing experiments, combined with the likelihood that Mn‐rich solutions flow over slag surfaces. A new model is proposed for the formation of silica glaze, involving soluble Al‐Si complexes and the nature of wetting films. Iron skins occur where runoff is concentrated, and where iron bacteria grow.

Observations indicate: (i) substrate can be important in supplying Mn, as well as maintaining a stable surface and channelling runoff to microspots where varnish grows; (ii) ignorance of boundary layer pH/Eh conditions makes chemical‐physical models of varnish formation speculative; (iii) the balance between cementation of recently nucleated varnishes and erosional shear stresses is poorly understood, but is probably an important limiting factor on varnish growth rates; and (iv) there must be at least two steps in biotic varnishing‐accretion of Mn‐Fe in casts, followed by cementation of clays by either in situ cast residue or Mn‐Fe remobilized from casts. Varnish accretion may be limited by the rate at which both steps occur. Rapid development of readily distinguishable manganiferous rock varnishes at this post‐1952 site highlights the danger of speculation on the ages of landforms based solely on the appearance of rock‐varnish coatings.
Rates of rock surface lowering, Princess Elizabeth land, Eastern Antarctica
Authors: Spate A. P. , Burgess J. S. , Shevlin J.
Published: February 2007

A series of micro‐erosion‐meter sites on different rock types and in differing wind regimes was established and re‐read after four years on two sites in the Larsemann and Vestfold Hills. These two oases in Eastern Antarctica are subjected to both wind abrasion and salt wedging. The measurements displayed bimodal distributions, indicating that both abrasion and single‐grain detachment could be observed. Surface lowering rates of 0·015 and 0·022 mm a−1 were demonstrated for the Larsemann and Vestfold Hills, respectively.
Estimating the probability of river channel adjustment
Authors: Downs Peter W.
Published: February 2007

River channels respond not only to natural external controls, and natural controls internal to individual drainage basins, but also to the influence of human activity. Although many site‐specific instances of change have been documented, the complexity of the process interactions means that very little is known about the general nature of different styles of adjustment, or their relative sensitivity to drainage basin controls. Data obtained from the Thames Basin, southeast England, are used in a probabilistic approach to differentiate between four styles of river channel adjustment and a variety of drainage basin characteristics. Adopting a probabilistic approach quantifies the degree of confidence attributable to any prediction of river channel adjustment while acknowledging that certainties are difficult to obtain in studies of the natural environment. This approach could thus allow environmental planning decisions to be made with a quantified degree of uncertainty.

Four multivariate logistic regression models are described which use a combination of continuous and categorical variables to associate drainage basin characteristics with four styles of river channel adjustment derived from a reconnaissance evaluation survey. In comparison, it is shown that laterally migrating river channels are the most common ‘natural’ channel type in the Thames Basin, and their probability of occurrence rises to 71 per cent in sand/gravel environments. In channels regulated by low weirs, deposition is the most likely channel activity where gradients are lower than 0·0040, whilst above this threshold the majority of channels are morphologically inactive. In urban channels, many of which are also lined by concrete, the likelihood of obtaining a stable channel is mostly in excess of 80 per cent. In channels straightened during this century, deposition is most likely in gradients below 0·0050, whereas erosional enlargement is most probable above this value. In channels which were initially channelized prior to this century, deposition gives way to stability at a threshold gradient of 0·0080.
The holocenic evolution of a stretch of an eastern italian alpine valley
Authors: Friz Corrado , Villi Vigilio , Turrini Maria Chiara
Published: February 2007

The morphological evolution of a stretch of an alpine valley located in the Eastern Italian Alps is described. This has been conditioned by a great alluvial fan that was formed as a consequence of interconnected events, deriving from large rockfalls which occurred in the late glacial period at the head of the Missiaga–Bordina valley, on the left side of the Agordo basin. The aggradation of the alluvial fan blocked the Cordevole valley south of the Agordo basin and produced a lake that is documented by lacustrine sediments. Age determination by 14C techniques on wood remnants found in these sediments fixes the life of the lake at between approximately 5880 and 5300 years BP. This represents, indirectly, the age of the main phase of the development of the fan. After the building up of the alluvial fan, an erosional phase began, leading to the formation of the present landscape. A series of illustrations depicts the sequence of the fan's development.
Comprehensive linkage and linkage heterogeneity analysis of 4344 sibling pairs affected with hypertension from the Family Blood Pressure Program
Authors: Greenwood Tiffany A. , Libiger Ondrej , Kardia Sharon , Hanis Craig , Morrison Alanna C. , Gu C. Charles , Rice Treva , Miller Michael , Turner Stephen T. , Myers Richard H. , Grove John , Hsiao Chin‐Fu , Weder Alan B. , Schork Nicholas J.
Published: February 2007

Linkage analyses of complex, multifactorial traits and diseases, such as essential hypertension, have been difficult to interpret and reconcile. Many published studies provide evidence suggesting that different genes and genomic regions influence hypertension, but knowing which of these studies reflect true positive results is challenging. The reasons for this include the diversity of analytical methods used across these studies, the different samples and sample sizes in each study, and the complicated biological underpinnings of hypertension. We have undertaken a comprehensive linkage analysis of 371 autosomal microsatellite markers genotyped on 4,334 sibling pairs affected with hypertension from five ethnic groups sampled from 13 different field centers associated with the Family Blood Pressure Program (FBPP). We used a single analytical technique known to be robust to interpretive problems associated with a lack of completely informative markers to assess evidence for linkage to hypertension both within and across the ethnic groups and field centers. We find evidence for linkage to a number of genomic regions, with the most compelling evidence from analyses that combine data across field center and ethnic groups (e.g., chromosomes 2 and 9). We also pursued linkage analyses that accommodate locus heterogeneity, which is known to plague the identification of disease susceptibility loci in linkage studies of complex diseases. We find evidence for linkage heterogeneity on chromosomes 2 and 17. Ultimately our results suggest that evidence for linkage heterogeneity can only be detected with large sample sizes, such as the FBPP, which is consistent with theoretical sample size calculations. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Presidential address to the liverpool geological society. The glacial geomorphology of the south‐eastern part of the lake district
Authors: Gresswell R. Kay
Published: February 2007

The south‐eastern part of the Lake District was glaciated almost entirely by local ice. The valleys show many typical features: cirques, cirque tarns, valley‐heads, U‐shaped troughs with over‐steepened sides, and change of slope above the maximum glacier‐ice level, hanging valleys, valley‐steps, rock barriers, paternoster lakes, rock‐basins, ice spillways, and a large variety of moraines, drumlins and roches moutonnés. The glaciers from Grasmere and Langdale converged on Windermere and there produced the northern rock‐basin. Ice spillways into the Kent and Winster valleys resulted in the shallow central part of the present lake. The addition of ice from the Esthwaite glacier produced the southern rock‐basin. The glacier moved southwards by Cartmel, but the present fluvial drainage follows Backbarrow Gorge to the Greenodd estuary.
Notes on the genera Prolecanites and Epicanites with descriptions of two new species
Authors: Moore E. W. J.
Published: February 2007

The type species of the genus Prolecanites is discussed. The generic name Paraprolecanites Karpinsky 1889 is invalid, being founded on a hypothetical suture line. Forms showing this type of suture line have since been found and the genus Epicanites was erected by Schindewolf 1926 to include such forms. A possible development from Prolecanites to Epicanites is suggested.
The lower carboniferous rocks of ireland
Authors: Turner J. Selwyn
Published: February 2007

Following introductory notes on the historical aspect of the subject, this review of Irish Carboniferous Limestone and associated beds discusses the distribution of the principal lithological types in Ireland. The zonal stratigraphy is then reviewed throughout the island, opportunity being taken to incorporate certain unpublished results of recent work. Then follows a résumé of the history of the period from the palaeogeographical point of view. Detailed bibliographies (a) by counties, (b) of more general papers, are prefixed to the paper.
Composite minor intrusions, and the slieve gullion complex, ireland
Authors: Bailey E. B. , McCallien W. J.
Published: February 2007

The paper consists of two parts, both furnishing evidence that partially consolidated basalt can chill against penetrating acid veins. This recalls work by R. E. Wilcox on a mixed lava at Gardiner River, 1944. Part I is mainly concerned with certain composite intrusions where basic margins carry quartz xenocrysts and acid interiors carry quartz phenocrysts. It is argued that basalt magma rose from a deep source through quartz‐porphyry rock, melting and incorporating contacts. Presently the quartz‐porphyry melted bodily, and, no longer penetrable, followed its basaltic forerunner into the upper world. Being cooler than the basalt, it often appreciably chilled what it did not drive forward. Part II introduces some new features into the structural interpretation of the North‐West Belt of intrusions at Slieve Gullion, and claims that these intrusions and also the ring‐dyke of earlier date have been accompanied by marked distortion of country‐rock. The granophyre of the North‐West Belt seems to be essentially earlier than the associated dolerites. These latter melt the granophyre at contact and chill against rheomorphic veins. Much of D. L. Reynolds' work from 1937 onwards is accepted, including extensive remaking of Newry Devonian granodiorite under Tertiary conditions; but certain hypotheses of surface volcanitity and deep‐seated metamorphism are criticised.
New record of the gastrioceras listeri marine band in flintshire
Authors: Shanklin J. K.
Published: February 2007

Recent brings by the National Coal Board/Opencast Executive in the Mostyn Area have shown the presence of the Grrctrioceras listen' Marine Band some 90 feet above the Garrrioceru subcrenatm Marine Band. Faunal assemblages from these horizons are here lisred and a sketch map (Fig. 1) of the area is presented.

The sigdicance of the record is noted and an earlier record of G. lisrm' near Connah's Quay referred to.
Mobilisation of Granophyre in Eire and sinking of Olivine in Greenland
Authors: Bailey E. B.
Published: February 2007

I. Two quarries show Tertiary dolerites of the Carlingford Complex traversed by granophyric veins against which the dolerites chill. The veins have almost certainly resulted from remelting.

II. A picritic sill in Ubekendt Ejland, West Greenland, can be harmoniously interpreted as owing much of its character to pre‐intrusion sinking of olivine in an underlying supply‐reservoir. It also shows repeated evidence of marginal magmatic erosion during intrusion, and this has affected its post‐intrusion cooling.
The Nantglyn Flags; Mid‐Salopian basin facies in Wales
Authors: Cummins W. A.
Published: February 2007

The Nantglyn Flags consist of very thinly interbedded mudstones and laminated muddy siltstones with less frequent thin beds of calcareous siltstone. The lithology, sedimentary structures and fauna of these three rock types are described and discussed. It is concluded that the calcareous siltstones bed were deposited by turbidity currents.
New work on petrofabrics
Authors: Voll G.
Published: February 2007

Recent work on petrofabrics, particularly work written in German, is reviewed in the light of the author's own experience. Topics discussed include quantitative comparison of fabric diagrams, the thermodynamics of crystal growth under stress, interpretation of grain boundaries, comparison of fabrics of metal and silicate crystal aggregates, recrystallisation fabrics, quantitative evaluation of rock deformation using parameters of ooliths, fossils and folds, and structural sequence in orogenic zones.
A Ludlovian facies boundary in south Central Wales
Authors: Bailey R. J.
Published: February 2007

Over much of its outcrop in south Central Wales, the earliest facies of the Ludlovian, comprising grey shaly mudstones, is overlain by an important turbidite facies. In the present paper these two facies are described and the boundary between them is fixed at the first appearance in the succession of numerous thick turbidite beds. While its horizon cannot be precisely defined with reference to the faunal sequence, there are grounds for believing that this boundary is not significantly diachronous in the area considered. Finally, some suggestions are made as to the possible significance of the facies boundary.
Natural liquids and the phonolitic minimum
Authors: Carmichael I. S. E.
Published: February 2007

The composition of the feldspar phenocrysts, and the enclosing glassy or finely crystalline ground‐masses, of three phonolites suggests that the addition of calcium or the addition of excess sodium (molecular ratio Na2O + Ka2O > Al2O3) to compositions in the feldspar field of the system NaAlSiO4‐KAlSiO4‐SiO2 will change the composition of the minimum on the nepheline‐feldspar boundary when this is projected into this system.
Palaeozoic deformation at Woodstown, Co. Waterford
Authors: Dewey J. F. , Rast N.
Published: February 2007

Structures in an Ordovician inlier are described and regional conclusions are reached from the evidence at this critical locality.
Late Caledonian dyke‐swarms in Southern Scotland: New field, petrological and geochemical data for the Wigtown Peninsula, Galloway
Authors: Barnes R. P. , Rock N. M. S. , Gaskarth J. W.
Published: February 2007

Several hundred, dominantly NE‐trending dykes invade Silurian flysch sediments of the Wigtown Peninsula. The most basic dykes are K‐rich biotite‐lamprophyres, hornblende‐lamprophyres and appinites ('diorites' of previous maps). More acidic (qz and cm normative) dykes include restricted andesitic compositions ('porphyritcs', c. 57 per cent SiO2) and a continuum from dacitic to rhyolitic compositions ('acid porphyrites' and 'porphyries', c. 63–71 per cent SiO2). The relative abundance of basic to intermediate + acidic dykes, based on examination of 180 thin sections and 70 new whole‐rock analyses, is approximately 7:1. The biotite‐ and hornblende‐lamprophyres are distinct in chemistry and distribution, biotite‐lamprophyres being confined to the south of the Peninsula. Neither type has any compositional equivalent among the plutonic rocks of the area. Porphyrite and porphyry dykes do not represent simple lamprophyre fractionates, but may be derived from at least two (intermediate and acidic) parent magmas, which may represent crustally‐contaminated lamprophyre or entirely separate crustal melts. Emplacement of all dyke compositions was apparently episodic through Wenlock to early Devonian times (c. 425‐395 Ma). Early dykes post‐date the main deformation (D1) but predate minor (D2) folding, both D1 and D2 being related to thrusting. On the current accretionary model for the Southern Uplands, this implies that dyke emplacement commenced before the end of accretion in a compressional tectonic regime—scarcely consistent with the moderate (up to 6 per cent) crustal extension represented by the dykes. The geochemistry of the lamprophyres requires a deep mantle origin several hundred kilometres behind any subduction zone. This suggests that the 'lapetus suture', at the time of dyke emplacement, was much farther south than its currently inferred position and places the Southern Uplands in a back‐arc situation.
Dinantian sedimentation and the basement structure of the Derbyshire Dome
Authors: Gutteridge Peter
Published: February 2007

The depositional history of the Dinantian on the Derbyshire Dome can be divided into three phases: (1) pre‐Holkerian: onlap of an irregular basement surface by evaporite and carbonate sediments, (2) Holkerian to Asbian: sedimentation on a carbonate shelf formed by the merging of early Dinantian depocentres following burial of the basement topography, and (3) Brigantian: formation of intrashelf basins and the development of a carbonate ramp on part of the pre‐existing shelf.

A model of the basement structure underlying the Derbyshire Dome is presented to explain the location of the Brigantian intrashelf basins and carbonate ramp. The basement consists of two main tilted fault blocks separated by a smaller tilt block. Movement on faults bounding the tilt blocks caused the development of intrashelf basins. The basin margins were controlled by structures which developed in the cover sediments. The carbonate ramp present during the late Brigantian developed in response to an eastward tilting of the basement.
The stratigraphy and structure of the Galley Head culmination zone: An area of enhanced shortening related to basin geometry within the Irish Variscides
Authors: Ford Mary
Published: February 2007

In southwest Ireland an Upper Devonian to Lower Carboniferous clastic succession was deposited in an ENE–WSW trending half‐graben, known as the South Munster Basin. Across the Galley Head peninsula on the south coast, this stratigraphical succession is attenuated due to the presence of a palaeogeographical feature called the Glandore High. Evidence suggests that the Glandore High was an east–west feature, faulted to the north and east, which was part of the southern flank (hangingwall rollover) of the South Munster Basin.

During post‐Carboniferous Variscan deformation the relatively thin stratigraphy of Galley Head underwent prolonged folding, causing a local periclinal fold pair to develop within the hinge zone of a regional syncline. The main cleavage then developed parallel to bedding on the overturned south limb of the anticline of this fold pair. The local enhanced shortening caused the development of a structural culmination, and south facing, tight to isoclinal folds. The culmination was enhanced and tightened by a fault system of contractional, strike‐parallel faults linked by cross faults. Secondary folds occur across the hinges of regional anticlines and also on major fold limbs as isolated fold pairs and in monoclinal fold zones, some of which may have nucleated on irregular sandstone bodies. Local crenulation cleavages are related to late fault movements. Syn‐cleavage, conjugate, wrench faults record 10 per cent to 15 per cent strike‐parallel extension in the culmination.

The deformation chronology of the Galley Head area is somewhat anomalous for the Irish Variscides in that the folds were well established before the onset of the main cleavage development. The enhanced shortening across the area was compartmentalized by major cross faults and a minor component of north–south sinistral shear was also active across the area causing a swing in strike and a late set of minor cross faults.

Structural facing directions in southwest Ireland appear to be directly linked with the geometry of the deformed basins. Hence the southward facing along the south coast is due to the proximity of the southern margin of the South Munster Basin. Structural facing directions fan northwards across the basin and major folds are overturned to the north at the northern margin of the basin.
Cleaved microgranite dykes of the Shap swarm in the Silurian of NW England
Authors: Soper N. J. , Kneller B. C.
Published: February 2007

Felsite‐microgranite dykes, chemically comparable with the Shap swarm and associated with the Shap intrusion, are present in Silurian sediments of the southern Lake District. They were emplaced after the country rocks had undergone Acadian (late Caledonian) folding and cleavage‐formation but are themselves weakly cleaved. This confirms a ‘flattened buckle’ model for the Acadian deformation in NW England, which in turn establishes the link between sinistral transpression in this region and the clockwise transection of the folds by cleavage. The evidence also shows that the Acadian cleavage developed episodically, and that the Shap‐Skiddaw magmatism occurred during one or more stress‐relief episodes. The emplacement age of these intrusions thus constrains the age of the Acadian orogeny in NW England which was late in the Lower Devonian (according to currently available isotopic evidence), significantly later than the Silurian deformation of the Southern Uplands.
Per migma ad magma downunder
Authors: White Allan J. R. , Chappell Bruce W.
Published: February 2007

According to some early definitions, ‘magma’ had to be completely molten so that granitic rocks containing residual material from their source (restite) were not considered to be magmatic. Granites and volcanics with abundant recognizable restite were called migmatites or migmatitic rocks, and this terminology appears to be still in use by some. However, many felsic granites and volcanics commonly contain at least some restite, and for this reason we suggest that magma be defined either as melt or as rock material with enough melt for it to become mobile and intrusive or extrusive. The rocks crystallizing from these magmas are igneous. They are not migmatites. On the other hand, we suggest that migmatites be defined as rocks that did not have sufficient melt to become mobile; they retain a structural coherency even though the structures may be complex. Differences between the two rock types result from the amount of melt phase. When a critical melt fraction is reached during partial melting, there is a rapid change from migma to magma (migmatite to granite).

The geochemistry and mineralogy of migmatites tell us little about reactions that produce more melt and hence about granite formation because of back reactions and other processes that occur during the cooling of migmatite. Back reactions mostly involve H2O that is not lost from the migmatitic system. Because H2O is lost by processes of second boiling and pressure quenching during the crystallization of granite magmas at or near the surface, it is these rocks and their inclusions, not migmatites, that provide the most information about sources and processes of granite formation.