bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional morphology and affinities of extant Chelicerata in evolutionary perspective
Authors: van der Hammen L. 
Published: November 2011

ABSTRACTA survey is given of the functional morphology of extant Chelicerata with special reference to segmentation of the body, segmentation and articulation of the legs, coxal glands, mouthparts and ingestion, respiratory organs, sperm transfer, and development. This is followed by a discussion of primitive types, evolution and diversity, the transition from aquatic to terrestrial life, and the affinities of extant chelicerate groups.
Pelagic trilobites as an example of deducing the life habits of extinct arthropods
Authors: Fortey R. A. 
Published: November 2011

ABSTRACTThis paper reviews the methods which have been used to deduce the life habits of trilobites. The most reliable conclusions are those that satisfy three independent criteria of evidence: (1) functional morphology of the exoskeleton; (2) analogy with living arthropods; and (3) geological evidence, as from facies relationships, or palaeogeography. Pelagic trilobites are one of the better examples for life habit reconstruction. The Ordovician trilobites that were most probably pelagic are those with hypertrophied eyes—Telephinidae, Opipeuteridae, Bohemillidae and Cyclopygidae—which satisfy the threefold requirements for evidence.Opipeuter, Carolinites(and other telephinids) were probably epipelagic, whereas cyclopygids andBohemillawere likely to have been mesopelagic, living in exterior sites around the perimeter of Gondwana in the earlier Ordovician. These pelagics divide into two morphological groups: poorly streamlined, sluggish species somewhat like the living hyperiidParathemisto, and well-streamlined species which are larger, and are considered to have been fast and active swimmers, with predatory habits. The streamlining of this group has been demonstrated by experiment. Other trilobites may also have been pelagic, but the evidence is less complete:Irvingellaand its homeomorphs, andRemopleurides. Most Olenidae, however, which have been supposed to have been pelagic, were benthic forms inhabiting a specialised environment low in oxygen and possibly below the thermocline; only the leptoplastines may have been pelagic.It is also shown that there are cases where ventral terrace ridges did not function to grip sediment during filter feeding. This applies not only to pelagic trilobites, but also to benthic ones in which the width and disposition of the doublure renders engagement with the sediment unlikely.
Trilobite abnormalities
Authors: Owen Alan W. 
Published: November 2011

ABSTRACTThere is abundant evidence of injury, teratology and pathological conditions in trilobites although it is commonly difficult to distinguish between their morphological results. Many injuries were probably sustained during moulting, with spines, bilamellar fringes and narrow gaps between dorsal exoskeleton and doublure being most vulnerable. Some injuries were the result of predaceous attack and provide important clues to the trophic structure of Palaeozoic communities. Many injuries show evidence of repair. Some supposedly teratological conditions, most notably the number of paradoxidid thoracic segments, are so common that they must be considered part of normal variation. Others represent genetic mutation or ontogenetic malfunction, the latter possibly externally induced. Undoubted pathological conditions are restricted to swellings and borings presumably caused by parasitic infestation.Abnormalities affecting lateral areas are more common than those involving the rachis and glabella and this probably reflects both greater mortality when the axial region is involved, and greater vulnerability of peripheral regions to predaceous and moulting damage. The first explanation also accounts for the rarity of cephalic abnormalities compared to those of the pygidium.
Life habit and enrolment in Calymenacea (Trilobita) and their significance for classification
Authors: Hammann W. 
Published: November 2011

ABSTRACTThe life habit ofNeseuretusis reconstructed on the basis of functional analysis and compared with that of other Calymenacea.Neseuretus, like all Calymenidae, was probably a filter feeder, burrowing downward into the sediment, where it rested hidden in a U-shaped attitude. Homalonotidae developed frontal burrowing and Bathycheilidae probably lived on the sediment. These calymenid families have different enrolment and behavioural patterns. Enrolment structures are developed, analysis of which leads to an understanding of phylogeny. Bathycheilidae maintained an unspecialised spiral enrolment. Flexicalymeninae and Calymeninae developed an advanced spiral enrolment, while a pseudosphaeroidal enrolment was achieved along independent lines in Kerfornellinae and Homalonotidae.
Collision zone between the Kohistan arc and the Asian plate in NW Pakistan
Authors: Pudsey C. J. , Coward M. P. , Luff I. W. , Shackleton R. M. , Windley B. F. , Jan M. Q. 
Published: November 2011

ABSTRACTThis paper describes the suture zone between the Asian plate and the accreted Kohistan island arc in the Chitral district of NW Pakistan.The southern part of the Asian plate consists of two tectonic units separated by the N-dipping Reshun fault. The northwestern unit comprises Devonian carbonates and quartzites overlain by Devonian to Permian shales and slates with some limestones (Lun shales). Its structure is complex with S-verging thrusts and isoclinal folds. Along the Reshun fault, the relatively undeformed Reshun Formation may represent molasse. The central unit includes N-dipping Upper Palaeozoic slates and quartzites (Darkot Group), probably faulted against an antiformal tract of slates, schists derived from a volcanic assemblage and Cretaceous limestones (Chitral slate, Koghozi greenschist, Krinj and Gahiret limestones). Asian plate sediments are intruded by granitic and granodioritic plutons, variably deformed and locally porphyritic.The Northern suture melange of volcanic, sedimentary and serpentinite blocks in a slate matrix separates the Asian plate from the southeastern unit, the Kohistan arc. This comprises Cretaceous volcanic rocks with some sediments (Shamran Volcanic Group, Drosh, Purit and Gawuch Formations) intruded by aphyric diorites, tonalites and granites. These intermediate plutonic rocks pass southwards into a mafic layered complex and amphibolites representing deep levels of the arc. The volcanic rocks and sediments dip to the N and have a horizontal lineation. The structural history of southern Asia and Kohistan is consistent with an originally curved Northern suture: motion of the arc was initially to the NE relative to Asia and subsequently to the NW.
Palaeoecology and sedimentology of the Achanarras fish bed of the Middle Old Red Sandstone, Scotland
Authors: Trewin Nigel H. 
Published: November 2011

ABSTRACTThe Achanarras fish bed of Middle Devonian age in the Orcadian Basin was deposited in a large freshwater lake of variable productivity in which thermal stratification was normally developed. The fish bed consists of lacustrine laminites of organic, carbonate (dolomite and calcite) and clastic types. Carbonate laminae were precipitated as a result of photosynthetic activity and organic laminae were deposited following algal decay, clastic material was introduced by processes including overflow and interflow currents and wind transport.The fish bed represents a major lacustrine transgression during a wetter climatic period which provided connections to other lakes and by overflow to the sea. Calcitic laminites represent the deepest water (>60 m) phase with greatest faunal variety due to availability of migration routes and stability of environments caused by lake overflow.Initial lake transgression was characterised byDipteras-dominated faunas which reappear as the last surviving fish during lake regression. Further regression resulted in the introduction of turbidites to the laminites.Many fish were preserved following mass mortalities induced by algal blooms, mixing of waters by storms and lake overturn. Most of the fish inhabited shallow areas of the lake and drifted as rotting carcases to their final site of deposition. The fauna comprises a variety of benthonic and nektonic fish including predators, scavengers and omnivorous forms. Fish such asCoccosteusrepresented almost exclusively by adults may have bred outside the area of the lake.
Arthropod larvae from the Upper Cambrian of Sweden
Authors: Müller Klaus J. , Walossek Dieter 
Published: November 2011

ABSTRACTFour tiny obvious larvae unassignable to larger “Orsten” arthropods are described and reconstructed. Two of them have a naupliar appearance and may belong to crustaceans, whereas the other two represent as yet unknown types of euarthropodan larvae.
The structural evolution of the Dalradian of the Central Highlands of Scotland
Authors: Treagus J. E. 
Published: November 2011

ABSTRACTThe first section of the paper is concerned with a detailed account of the structure of the classic Schiehallion area. The account is extended to the flat belt via the Glen Lyon-Ben Lawers area. It is demonstrated that major D1 folds involve the whole of the Appin and Argyll groups and now face SE. However, the original D1 folds were probably open upward-facing folds which have been refolded and modified by the dominant D2 deformation. D2 is represented by an antiformal complex which culminates downwards in the Boundary Slide, a zone of strong deformation associated with NW translation of Dalradian over the ‘young Moine’ rocks. D3 has been responsible for the rotation of the originally flat D2 structures into their present ‘steep’ attitudes N of Glen Lyon. D4 is represented by the strike-swing of the lower Dalradian formations, possibly related to early movements on the two major faults that bound the area. The concept of a D1 Tay Nappe which roots in the ‘young Moine’ to the N is retained, although the scale and flat attitude of that fold is regarded as in part a product of D2.
Sedimentology of part of the Lower Oil-Shale Group (Dinantian) sequence at Granton, Edinburgh, including the Granton “shrimp-bed”
Authors: Cater John M. L. 
Published: November 2011

ABSTRACTThe Dinantian Lower Oil-Shale Group of the Edinburgh area records the evolution of a SW–NE trending basin within an area of fluvial-dominated deltaic sedimentation, with rare marine incursions from the E. The sequence at Granton records the abandonment of a delta lobe, with deltaic sandstones overlain by lagoonal mud-shales. These thinly-laminated non-bioturbated mud-shales record low-energy, stagnant conditions. Fish, ostracodes and conchostracans inhabited the lagoon at this time.Within the mud-shale sequence is the dolomitic Granton “shrimp-bed” which contains fenestrae, possible gypsum pseudomorphs andin situshrinkage breccias suggesting periods of emergence. The “shrimp-bed” contains a number of laminae packed with soft-bodied fossils including marine forms, which resulted from brief marine incursions into the stagnant lagoon. The fluctuating salinity conditions seem to have favoured the development of an unusual fauna of shrimp-like crustaceans, fish, conchostracans, ostracodes and bellerophontid gastropods. This fauna appears to have suffered periodic mass mortalities during marine incursions which brought orthocone cephalopods, polychaete worms and conodonts into the lagoon, according to our current knowledge of the distribution of these marine taxa in the sequence.The Granton sequence displays a variety of ductile and brittle deformation features most of which can be attributed to local SW-directed extension related to regional dextral strike-slip across the Midland Valley of Scotland.
Niveo-aeolian sand deposits on An Teallach, Wester Ross, Scotland
Authors: Ballantyne Colin K. , Whittington Graeme 
Published: November 2011

ABSTRACTDeposits of windblown sand up to 4 m thick on the Torridon Sandstone massif of An Teallach are shown to be of predominantly niveo-aeolian origin, a form of sedimentation hitherto unrecognised in upland Britain. Sand grains weathered from bedrock and from exposed clasts on plateau areas are blown on to the winter snowpack on surrounding slopes. When the snow melts, the grains are lowered on to the underlying vegetation, which traps the sand and thus allows a stable deposit to accumulate. The deposits formed in this way are massive, poorly sorted and coarser than most aeolian deposits, comprising mainly medium sand (212–600μm) with a substantial proportion of coarse sand and even very small pebbles. The coarseness and poor sorting of the sands reflect the size of grains available for transportation, the strength of the wind, short transport distances and admixture of different grades of sand during deposition. Sand accumulation began in the Early Flandrian before c. 7900 BP, but was eventually much reduced by the establishment of vegetation cover over the plateau source area. Recent disruption of this vegetation cover triggered either by increased storminess or overgrazing resulted in extensive erosion of sand deposits on the plateau and their redeposition on surrounding slopes. Niveo-aeolian deposition continues on lee slopes at present, but is offset by erosion of unvegetated scarps at the margins of the deposits.
Formation of late Caledonian subvolcanic breccia pipes at Cruachan Cruinn, Grampian Highlands, Scotland
Authors: Platten I. M. , Money M. S. 
Published: November 2011

ABSTRACTPipe-shaped breccia bodies associated with diorite intrusions are composed mainly of angular clasts of local schists with a few transported clasts of quartzite. Plate shaped fragments are commonly oriented to define planar fabrics in the breccias. These features indicate the operation of gas fluidisation within the pipes and both entrainment and expanded bed conditions are inferred. The fabrics result from the collapse of the fluidised suspensions as the gas flow declined. Dilational fracture patterns in the country rock comparable with the stress release patterns found around mine shafts can be matched with the fractures required to produce the angular schist clasts. It is concluded that fracturing and the introduction of fragments into the fluidised breccia system was a continuous process and that the pipe diameter increased progressively with time. Microdiorite sheets and related stock like bodies of diorite cut and metamorphose the breccias. Compaction, hornfelsing and hydrothermal alteration also contributed to breccia formation.
The use of long-term rainfall records for augmenting historic flood series: a case study on the upper Dee, Aberdeenshire, Scotland
Authors: McEwen L. J. 
Published: November 2011

ABSTRACTEstablishing the magnitude and frequency of floods within upland catchments on the basis of short-term gauged runoff records is crucially dependent upon the extent to which the record is truly representative. In the case of the River Dee, upstream of Crathie in Aberdeenshire, gauged discharge records are limited in length. Although the middle Dee has been gauged since 1929, the gauge within the upper catchment has only ten years of record. Thus, reliable estimates of the return intervals of extreme floods for this part of the Dee can only be obtained by using a variety of historical sources to extend the flood series.Long-term rainfall records, where available, provide a valuable independent check on the reconstructed flood series. Such rainfall records, when analysed in terms of the magnitude, frequency and duration of major events, should, in general terms, correspond with the flood series. In this paper, the recurrence interval of extreme rainfalls of varying magnitude and duration in upper Deeside is estimated by extreme value analysis of the annual maximum series. The frequency of rainfall events above varying thresholds is also assessed. The existence of climatic fluctuations giving highly variable recurrence intervals for rainfall events of the same magnitude is demonstrated. Finally, the seasonality of frequent flood-producing storms is analysed. Patterns observed within the rainfall record are compared with those previously established within the historic flood series to substantiate and augment the flood record.
The hydrology of a drained, afforested peat bog in southern Scotland, 1977–1986
Authors: Ledger D. C. , Harper S. E. 
Published: November 2011

ABSTRACTThis paper reports on the progress to date of a long-term investigation of the effects of drainage and afforestation on the hydrology of a peat bog near Edinburgh based on the use of runoff plots and other related equipment. The hydrology of the area immediately after ploughing is described and recently collected data are presented to show how this has changed over a six-year period. The main changes appear to be a substantial reduction in water yield and a move towards a less flashy runoff regime. Data are presented to show that these are most probably due to an increase in the amount of rainfall intercepted by the vegetation now covering the area and to a deterioration in the hydraulic efficiency of the drainage network.
Flood frequency estimation in Scotland using index floods and regional growth curves
Authors: Acreman M. C. , Werritty A. 
Published: November 2011

ABSTRACTThe index flood/regional growth curve method is the most commonly used procedure for estimating a design flood at an ungauged site in the United Kingdom when only the instantaneous peak discharge is required. This paper summarises recent work in Scotland in which the authors have refined the equations for estimating the index flood from the physical characteristics of the drainage basin and have proposed new methods for classifying basins to increase the hydrological homogeneity of the regions on which the growth curves are based. A new algorithm for estimating regional growth curves is reported which allows for correlation between flood magnitude at different sites. Simulation experiments are described which highlight the consequences of the data failing to meet the assumptions of the models used.
Solute leaching in light-textured soils: prediction of solute leaching in light-textured soils using a chromatographic plate method
Authors: Vinten A. J. A. , Yazid S. , Naysmith D. B. , Parkes M. E. 
Published: November 2011

ABSTRACTThe leaching of non-adsorbed tracer ions was studied at two field sites and in undisturbed columns. Results of field work are compared with leaching predicted using a simple chromatographic plate model. This comparison shows that in most cases less leaching than predicted occurs. This suggests that nitrate ions may be protected from leaching in field soils because of the presence of immobile water, and column experiments support this hypothesis. The extent of protection is larger than observed in other work for soils of similar texture.
A re-assessment of phosphorus inputs to Loch Leven (Kinross, Scotland): rationale and an overview of results on instantaneous loadings with special reference to runoff
Authors: Bailey-Watts A. E. , Kirika A. 
Published: November 2011

ABSTRACTConcern over the effects of eutrophication of Loch Leven led to an assessment of the phosphorus (P) loading and the contributions from runoff (from a catchment area of 145 km2), rain on the loch, roosting wildfowl, treated sewage effluent and P-rich industrial waste. Integrated programmes of flow gauging and nutrient analyses on twelve stream systems were carried out at eight-day intervals from January 1985 to February 1986. The paper concentrates on runoff and is restricted largely to total phosphorus (TP) loadings estimated from instantaneous flow and concentration data. The potential for deriving continuous loadings is discussed; examination of instantaneous and continuous discharge figures for a major inflow suggests that the present sampling regime has characterised its hydrological behaviour well. Nearly 90% of the water enters the loch in four streams of 0·1–1·0 m3 s−1 mean flow. The total input of water was high in 1985–134·4 × 106 m3 which is equivalent to a flushing rate of 2·6 (loch volumes); the effect on the loading results of the unusually wet study period is discussed.Inflow concentrations of TP ranged from <10μg 1−1 to c. 4 mg 1−1; they generally increased with increasing flow but co-efficients of determination (r2 values) were only ≦0·57. Rating curves based on log load/log flow gave, for most waters, r2 values of 0·85, suggesting that load-flow, rather than concentration-flow models, will prove more favourable for predicting loads on non-sampling dates.The total TP loading in runoff in 1985 was 9·4 tonnes, 38% of which was in soluble reactive form (SRP). Losses of P varied between sub-catchments, with 0·41–1·67 kg TP ha−1 yr−1 and typically <0·25 kg SRP ha−1 yr−1—representing only 5% of the annual agricultural applications of P. Initial calculations of inputs from sewage treatment works and industry suggest that these point-sources together contribute at least as much TP as in runoff, and twice the SRP in runoff. The significance of these findings for P control is discussed.
Petrology and geochemistry of post-obduction dykes of the Ballantrae complex, SW Scotland
Authors: Holub F. V. , Klápová H. , Bluck B. J. , Bowes D. R. 
Published: November 2011

ABSTRACTDoleritic intrusions known to post-date the obduction of the Ballantrae complex during Arenig times record changing magma provenance during the cooling and serpentinisation of obducted peridotite. There are two groups of dolerites with different petrographical and geochemical characteristics.The earlier emplaced group, which is subordinate, is characterised by amphibole formed under low metamorphic facies conditions and the virtual absence of Fe–Ti oxides. Chemically these rocks are of primitive tholeiitic character and are similar to modern island-arc basalts. They were derived from a strongly depleted mantle source region. The source region of the later emplaced group, which is predominant, was much less depleted. Clinopyroxene and plagioclase, much of it albitised, are the dominant minerals. Fe–Ti oxides also are common and there are pronounced chilled margins and well-preserved ophitic textures. Although showing mildly alkaline tendencies, these rocks originated from a tholeiitic parental magma of “within-plate” type.Both groups show evidence of rodingitisation and associated alteration related to serpentinisation of the peridotite. During the metasomatic activity, only some elements were mobile, while Al2O3, total Fe, MgO, TiO2, Cr, Ni, Nb, Y and Zr remained almost constant. Assessment of original magma type and geotectonic environment, and demonstration that both groups of doleritic rocks show the products of fractionation, has relied heavily on data for the apparently immobile elements and on petrographical study which identified those rocks least affected by alteration.