bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stratigraphy and sedimentology of the Devonian Rhynie chert locality
Authors: Trewin N. H. , Rice C. M. 
Published: January 2010

Synopsis
Recent drilling in the vicinity of the Rhynie chert locality in the Rhynie outlier of Lower Old Red Sandstone allows a local stratigraphic succession to be established. A basal lithic sandstone and pebbly sandstone unit of local derivation rests unconformably on basement, and was deposited in an alluvial fan environment. An andesitic lava flow, now highly altered, overlies the pre-lava sandstone, but is of limited lateral extent. The lava is succeeded by tuffaceous sandstones and shales which grade upwards into a shale-dominated sequence, with greatly diminished volcanic input. The volcanic debris is of local origin, probably derived from eroding tuff cones, but the general depositional environment was an alluvial plain with ephemeral lakes. The Rhynie cherts are siliceous sinters, comprising more than 10 plant-bearing beds and 2 non-plant-bearing cherts and are equivalent to part of the post-lava tuffaceous sandstone and shale sequence. A second plant-bearing chert, together with evidence of a hot-spring vent, has been discovered 700 m from the original locality.
The borehole evidence casts some doubt on the validity of the previously accepted stratigraphy of the Rhynie outlier, particularly with regard to the stratigraphic position of the Dryden Flags and Shales.
Lower Cambrian echinoderm ossicles from the Fucoid Beds, northwest Scotland
Authors: McKie Thomas , Donovan Stephen K. 
Published: January 2010

Synopsis
The Lower Cambrian Fucoid Beds of northwest Scotland contain a fauna that includes locally abundant, disarticulated, echinodern ossicles. These plates probably derive from an eocrinoid or some other, unknown primitive pelmatozoan. Available stratigraphic evidence indicates that the Fucoid Beds are Elankian or possibly upper Atdabanian, making this echinoderm one of the oldest known.
Reversals of movement sense in Lewisian brittle–ductile shear zones at Gairloch, NW Scotland, in the context of Laxfordian kinematic history
Authors: Shihe Lei , Park R. Graham 
Published: January 2010

Synopsis
Narrow (10–100 m wide) brittle–ductile shear zones in the Lewisian high-grade metamorphic complex of Gairloch, occur within broader ductile shear zones tens of kilometres across. The narrow belts contain ductile mylonites showing a sinistral sense of movement, which are cut and disrupted by brittle cataclasites indicating a dextral movement sense. These are in turn affected by sinistral brittle folds, and finally by N–S dextral pre-Torridonian faults.

The ductile mylonites are thought to represent strain concentration during later stages of the high-grade Laxfordian D2 event at
c.
1.7 Ga, associated with north-westwards overthrusting. The reversal to dextral shear shown by the cataclasites is linked with the regional D3 folds, steep shear zones and widespread, retrogression at
c
. 1.5 Ga, and ascribed to a re-orientation of the regional movement direction from NW–SE to N–S. The reversal of shear sense to sinistral during the D4 folding may be explained by clockwise rotation of the shear belts with respect to the regional shear direction as movement continued. The final change to N–S dextral faulting could be related either to late Lewisian strike-slip movements at
c.
1.4 Ga or to Grenvillian movements at
c.
1.1 Ga.
Evidence for Carboniferous thermochemical overprinting in the Cheviot Complex
Authors: Mitchell J. G. , Storetvedt K. M. , Robson D. A. , Abranches M. C. , Ineson P. R. 
Published: January 2010

Synopsis
Previous studies of the Lower Devonian lavas of the Cheviot Hills have shown them to contain an unusually complex remanent magnetization, and many lavas have given Carboniferous K-Ar ages which are not compatible with the geological evidence. Furthermore, the Cheviot volcanics display pronounced low temperature alteration, significant jointing and faulting, and a phase of post-volcanic siliceous veining. Further palaeomagnetic and radiometric studies have been carried out in order to establish whether or not the anomalous magnetic and isotopic results are related to the tectono-thermochemical processes and mineral alteration. K-Ar analyses of clay mineral concentrates of lava and vein material from eight sites all give Carboniferous ages; the lava-derived clay ages cluster around 325 Ma, while the clays from veins have ages close to 300 Ma. Palaeomagnetic studies of the intrusive rocks also show extensive low temperature oxidation of the Fe–Ti oxides, even in the compact and subglassy varieties. Magnetization is typically multicomponent (dual-polarity) and is no less complex than that observed in the lavas. Inferred single-component directions are consistent with those recognized in the extensive Permo-Carboniferous intrusive sheets of the region (the ‘Whin Sill’). It is concluded that Hercynian tectonic reactivation in the Cheviot region led to chemical and mineralogical modification of all of the rock units examined, finding explicit expression in low temperature oxidation, remagnetization, isotopic setting (or resetting) of the K-Ar system in clay minerals from the lavas, and the development (or rejuvenation) of siliceous veining in the SE of the Cheviot massif.
Glossary of Scottish mineral species—an update
Authors: Livingstone A. 
Published: January 2010

Synopsis
A literature survey over the period January 1981 to December 1990 reveals that about 132 mineral species new to Scotland have been discovered. This is a 32% increase over the previous decade and results mainly from electron probe-microanalyses. Silicates, oxides, hydroxides, sulphides and sulphosalts form the bulk of the compilation. Highlights of the decade include the discovery of platinum group minerals in Shetland, work on manganese oxides and hydroxides and clay minerals, tellurium and selenium minerals and the discovery and description of five new mineral species.
The structure of the Sea of the Hebrides Basin: an integrated gravity and seismic model
Authors: O'Neill P. S. , England R. W. 
Published: January 2010

Synopsis
By combining seismic and gravity data for the Sea of the Hebrides Basin it has been possible to overcome problems of sea bed multiples and poor energy transmission in seismic data where a sediment starved sea floor and extensive igneous intrusions and volcanic rocks close to the sea bed have previously inhibited detailed interpretation of the basin structure. Models for the basin structure, partly constrained by the seismic data, parallel to the dip and strike of the basin show a good correlation between calculated and observed gravity anomalies and are consistent with the onshore geology. The basin has a half graben geometry with late-Triassic syn-rift sediments thickening toward the eastward dipping Minch Fault, overlain by post-rift Jurassic sediments. Early Tertiary volcanism was followed by Oligocene extensional faulting.
Sedimentology of the upper Dinantian Charlestown Main Limestone: implications for the controls on cyclothem deposition, eastern Midland Valley of Scotland
Authors: Pickard Neil A. H. 
Published: January 2010

Synopsis
The Charlestown Main Limestone of the upper Dinantian (Brigantian) Lower Limestone Group was deposited in an intracratonic basin undergoing differential subsidence. In the eastern Midland Valley two areas of increased susidence are recognized, the Fife-Midlothian Low and the Central Low, separated by an area of reduced subsidence, the Burntisland High, centred on West Lothian and Central Fife. The Charlestown Main Limestone forms the base of a typical Yoredale cyclothem and the area of deposition was flanked to the NW and NE by fluvio-deltaic systems.
Five distinct lithofacies are recognized within the Charlestown Main Limestone (CML); bioclastic wackestones, argillaceous lime mudstones, mottled limestones, bioclastic grain-stone/packstones and carbonate buildups. Bioclastic wackestones are present at the base of the CML throughout the eastern Midland Valley. However, distinct regional differentiation of lithologies followed: buildups and bioclastic grainstones and packstones developed on, or near, the Burntisland High whereas fine terrigenous material (introduced from the flanking fluvio-deltaic systems) preferentially accumulated in the bounding lows where the CML is dominated by more argillaceous lithologies (the argillaceous lime mudstone and mottled limestone lithofacies). Progradation of prodeltaic muds from the NE curtailed carbonate deposition earlier in East Fife and accounts for the thinning of the CML towards this area. In distal areas, such as Midlothian, this progradation was heralded by an influx of fine terrigeneous sediment reflected in an increasingly argillaceous upper part of the limestone.
Eustasy appears to have been the primary control on the deposition of the Charlestown Main Cyclothem: sea level rise resulted in transgression and initiation of carbonate sedimentation while delta progradation, which curtailed carbonate production, was probably triggered by a sea-level fall. Differential subsidence and autocyclic processes (such as major channel avulsion) were secondary factors and controlled the distribution and thickness of lithofacies within the limestone and the nature of the overlying deltaic sediments.
The geochemistry of Llandovery and Wenlock age K-bentonites in the Southern Uplands
Authors: Pearce R. B. 
Published: January 2010

Synopsis
A stratigraphical and geochemical investigation of Silurian age K-bentonites from the Central and Southern belts of the Southern Uplands of Scotland indicates temporal differences in both the prevalent type of magmatism and possible tectonic settings. The data support current evidence of peralkaline to high-K subalkaline within-plate volcanicity during Llandovery times. However, new analyses of Wenlock age K-bentonites from the Raeberry Castle Formation in the Southern Belt indicate a predominantly calc-alkaline volcanic arc source for these ash deposits. This Wenlock age volcanism coincides with a pause, or slowing down, in subduction prior to closure of the Iapetus Ocean during the Late Silurian times.
Depositional setting of Permian and Upper Carboniferous strata of the Thornhill Basin, Dumfriesshire
Authors: McMillan A. A. , Brand P. J. 
Published: January 2010

Synopsis
Data from the field and Survey boreholes show the Coal Measures (Westphalian) in the Thornhill Basin to comprise an attentuated sequence of paralic strata in which restricted marine faunal assemblages, including representatives of the Vanderbeckei and Aegiranum Marine Bands, have been recognized at four horizons. The Thornhill Basin developed under an extensional regime as a result of dextral displacement on structures of Caledonoid (NE–SW) trend. However, intermittent normal dip-slip displacement on these faults caused uplift of the Southern Uplands, relative to the Midland Valley and Northumberland Basin, resulting in limited Dinantian sedimentation and only intermittent marine access during the Namurian. More sustained subsidence occurred during Westphalian time. Late Carboniferous to early Permian rifts along re-activated NW–SE-trending faults acted as foci for basaltic volcanicity prior to the deposition of sheetflood breccias and accumulation of desert dune sands. Oxidation beneath the late Carboniferous to early Permian land surface was responsible for reddening of the Coal Measures and replacement of coal.
A multiple till sequence near Ellon, Grampian Region: T. F. Jamieson’s ‘indigo boulder clay’ re-examined
Authors: Hall A. M. , Jarvis J. 
Published: January 2010

Synopsis
Jamieson in 1906 described an ‘indigo boulder clay’ lying beneath younger glacial deposits in the Ellon area, Grampian Region. A pitting survey has revealed that this unit (the Pitlurg Till) lies beneath Late Devensian glacial and glacifluvial deposits (the Hatton Till and the Kippet Hills Gravels and Sands) and rests on a basal till (the Bellscamphie Till). The Pitlurg Till contains palynomorphs of Kimmeridge Clay age and shows weak northerly fabrics, suggesting ice transport from the Moray Firth. Amino acid ratios for sparse included shells indicate that the Pitlurg Till is younger than Oxygen Isotope Stage 7 and may post-date Stage 5e. The Bellscaphie Till lies beneath weathered gravels at Tillybrex and probably predates Stage 5.
Late Devensian meltwater movement and storage within the Ochil Hills, central Scotland
Authors: Russell Andrew J. 
Published: January 2010

Synopsis
This study examines the origin and significance of spectacular bedrock channel forms and sedimentary sequences in the Ochil Hills, central Scotland. Channels and terraces form a discontinuous system extending 4 km from the main Forth valley into central Glen Devon via Glen Quey. It is suggested that as the Ochil Hills emerged above the Late Devensian ice sheet, large amounts of glacial meltwater flowed into the ice free area mainly from the margins of the Forth valley glacier. Meltwater entered Glen Devon via a series of deeply incised meltwater channels passing into a large ice-dammed lake with an overflow into Glen Eagles. Boulder-sized sediment forming a large delta confirms the tremendous erosional and transport capacity of flows entering the former ice-dammed lake. Glaciofluvial and glaciolacustrine sedimentation within the Ochil Hills was very sensitive to changes in ice-margin position and ice thickness due to the configuration of outlet spillways and cols. The Ochil Hills therefore acted as a major storage area for meltwater during deglaciation. The release of such stored meltwater may have taken place suddenly resulting in high magnitude floods or jökulhlaups whose erosional and depositional effects may have extended beyond the immediate area.
Mineral magnetic analyses of glacial diamicts from the Midland Valley of Scotland
Authors: Walden J. , Smith J. P. , Dackombe R. V. , Rose J. 
Published: January 2010

Synopsis
Mineral magnetic measurements are applied to samples from Late Devensian glacial diamicts from the Midland Valley of Scotland to assess the effectiveness of the mineral magnetic approach as a tool for sediment provenance indication. The results indicate that the magnetic mineral assemblages within the diamict sediments are strongly related to the underlying and up-ice lithologies and suggest ice-flow directions from west to east. Such inferences are consistent with published data on ice-flow patterns based upon other evidence (clast lithology, diamict matrix colour, drumlin orientations, striations, etc.). These data also stress the need for measurements of mineralogical or chemical components to be made on a particle size specific base.
The Moniaive Shear Zone: a major zone of sinistral strike-slip deformation in the Southern Uplands of Scotland
Authors: Phillips E. R. , Barnes R. P. , Boland M. P. , Fortey N. J. , McMillan A. A. 
Published: January 2010

Synopsis
The Moniaive Shear Zone is a recently delineated major zone of enhanced ductile deformation (up to 5 km wide) within the Southern Uplands of Scotland. The northern margin of the zone coincides with the Orlock Bridge Fault at the boundary between Ordovician and Silurian grey-wackes. Outwith the shear zone, the greywackes are typically weakly deformed, with the regional S1 fabric being developed within mudstone interbeds. Within the shear zone, Silurian Gala Group greywackes are deformed by locally pervasive linear and planar fabrics which yield a consistent sinistral sense of shear. The shear-zone fabric, in general, dips steeply towards the NW with its strike being sub-parallel to that of the regional S1 cleavage. Detailed petrological and micro-structural studies have demonstrated that the Moniaive Shear Zone comprises several zones of high strain enclosing lenticular domains of relatively low strain. The relationship between the Moniaive Shear Zone and the Cairnsmore of Fleet Granite indicates that the main phase of ductile movement on the zone occurred prior to 392 Ma although the exact age of ductile deformation on the shear zone is uncertain.
The geology of the Succoth–Brown Hill mafic–ultramafic intrusive complex, near Huntly, Aberdeeenshire
Authors: Gunn A. G. , Styles M. T. , Rollin K. E. , Stephenson D. 
Published: January 2010

Synopsis
The Succoth–Brown Hill Intrusion is a deformed mafic-ultramafic body exhibiting multiple phases of recrystallization and alteration as a result of regional metamorphism and shearing deformation associated with the Portsoy Lineament. It comprises dominantly metagabbro within marginal belts of ultramafic rocks, the latter commonly rich in clinopyroxene. The effects of late brittle faulting and attendant hydrothermal alteration are superimposed locally on the sheared lithologies. Primary magmatic features are rarely preserved.
The gross structure of the complex, deduced from field mapping, ground magnetic surveys and diamond drilling, has been modelled as a series of sheets steeply dipping to the SE. New gravity observations have revealed a local residual anomaly of about 7 mGal which indicates that the intrusion could extend to a depth of 2.5 km.
A comparison of lithological, mineralogical and structural features with those of the nearby Huntly Intrusion reveals many contrasts. It is suggested that the two intrusions are not related, having been derived from magmas of different compositions. A structural separation of the two bodies is indicated by the geophysical data. Furthermore, the much simpler history of alteration and deformation in the Huntly Intrusion suggests that the Succoth–Brown Hill Intrusion may be an earlier body.
Landform–sediment distributions within the northern part of the Younger Dryas Highland ice-field, Scotland
Authors: Bennett Matthew R. 
Published: January 2010

Synopsis
The aim of this paper is to describe the landform–sediment distribution within the northern part of the Highland ice-field, which existed in the Scottish Highlands during the Loch Lomond Stadial or Younger Dryas. Strong spatial variations in the distribution of both subglacial and ice-marginal landforms are described. The role of geology and variations in the dynamics of this former ice-field are discussed as possible explanations for the observed patterns.
The thermal aureole of the Lochnagar Complex: mineral reactions and implications from thermal modelling
Authors: Goodman S. , Lappin M. A. 
Published: January 2010

Synopsis
The Caledonian Lochnagar Complex in the NE Highlands of Scotland comprises a central granite and earlier marginal quartz diorites. Contact metamorphism of the Dalradian country rocks has caused a thermal overprint on upper amphibolite facies regional metamorphic assemblages. Distinctive assemblages in metapelites and amphibolites can be mapped across the aureole, showing that the thermal effects are greatest where the marginal quartz diorites occur. Mineral chemistry in the metapelites can be related to contact metamorphic reactions and to a change in bulk rock chemistry due to partial melting of the metasediments in the high-grade parts of the aureole. Amphibolites within the aureole show no evidence of partial melting; their mineral chemistry is controlled by contact metamorphic reactions.
The form of the aureole is a function of the different phases of intrusion, and mathematical modelling has been applied to distinguish between different intrusive scenarios. It is likely that two phases of contact metamorphism, related to early quartz diorite and later granite intrusion, were necessary to produce the highest grades of metamorphism. Mismatch between the modelled aureole shape and that observed in some areas is probably due to enhanced local heat flow and the lateral extension of the intrusion below the present erosion level.
The Sigmundur Complex, a ?Tertiary igneous centre in the northern Rockall Trough
Authors: Ritchie J. D. , Hitchen K. , Edwards J. W. F. 
Published: January 2010

Synopsis
Seismic reflection data have revealed the presence of a large dome-like volcanic structure in the northern Rockall Trough, known as the Sigmundur Complex. The complex comprises a single, nearly circular platform marked by scarp edges, with some evidence for intra-basalt sequence reflectors, representing the original depositional attitude of former lava flows, dipping away from an eroded central volcano. The complex is mostly buried beneath Lower Eocene–Recent sediments although the culmination of the structure does crop out at sea bed. A free-air gravity anomaly over the complex reaches a peak value of +600 gu. Gravity modelling suggests the presence of a large mafic plutonic mass immediately underlying the volcanic pile. The intrusion possesses an asymmetric shape with a sloping top and base at depths of 2.4–3.0 km and 24.8–25.4 km respectively. The diameter increases downwards from 3.6–7.2 km at the top to 14.5–21.1 km at the base.
The origin and significance of sheet joints in the Cairngorm granite
Authors: Glasser Neil F. 
Published: January 2010

Synopsis
The development of sheet joints parallel to topographic surfaces is a characteristic of granitic rocks. These sheet joints are well developed in the granite of the Cairngorm Mountains. Both preglacial and glacial origins have been proposed for these joints and their genesis i s an area of considerable uncertainty. In this study, a quantitative analysis of joint characteristics of the granite sheets in the Cairngorm Mountains was undertaken. Sheet joints can be divided into two distinct categories: a first set of near-horizontal sheets parallel to the upper plateau surfaces of the area and a second, steeply dipping set developed parallel to the walls of glacial troughs. Both the near-horizontal and the steeply dipping sheet joint s contain the same set of primary structural joints. In all localities the sheet joints lie parallel to the surrounding topography, suggesting that they represent unloading surfaces. The near-horizontal sheets are interpreted as the result of gradual surface lowering through the Quaternary, whilst the steeply dipping sheets exposed in trough walls may be the result of more rapid erosion during Quaternary glaciations.
The Ben Nevis Intrusive Ring Tuff, Scotland: re-interpretation of the ‘Flinty Crush Rock’ as part of an ignimbrite conduit in the roots of an ancient caldera
Authors: Burt R. M. , Brown P. E. 
Published: January 2010

Synopsis
Intermittently exposed around the margins of the Ben Nevis volcanic pile is a thin (< 5m) rhyolite with a well developed magmatic flow foliation that includes rock previously described as ‘flinty crush rock’. Previous models for the development of this ‘flinty crush rock’ suggested that it developed as a result of intense mechanical shearing during subsidence of the volcanic pile into the underlying Inner Granite. New field, petrographic and geochemical evidence presented here, indicate that the ‘flinty crush rock’ is magmatic and part of a larger body of flow-foliated rhyolite that represents the remains of an ignimbrite conduit formed during caldera collapse. Post-eruption closure of the conduit imposed a well developed flow-foliation on the rhyolite destroying any primary pyroclastic textures. The rhyolite is compositionally identical to a small outcrop of amphibole-biotite Inner Granite, suggesting an intimate and probably co-genetic relationship between flow-foliated rhyolite and Inner Granite magmas. It is recommended that the term ‘flinty crush rock’ be abandoned and replaced by ‘Ben Nevis Intrusive Ring Tuff. This unit affords a rare opportunity to examine a ring fracture conduit associated with a caldera-forming eruption.