bluuebunny/crossref_metadata_2025_split huggingface dataset:
The tectonic evolution of a Lewisian complex on Coll, Inner Hebrides
Authors: Drury S. A. 
Published: January 2010

Synopsis
The heterogeneous Lewisian rocks of Coll show the effects of at least six phases of deformation. The absence of common, penetrative linear fabrics, and of representatives of the Scourie swarm of basic dykes, so useful in relative dating in most areas of Lewisian, limits rigorous analysis and regional correlation of tectonic events. To some extent the limitations have been overcome by examination of the effects of each phase on earlier structures, and of the geometry of the fold forms produced.
Although some evidence points to earlier structures, the oldest decipherable event took place during granulite-facies metamorphism. Basic dykes were emplaced under the same conditions and were suitably modified. Since the intrusive episode the complex has been subjected to several tectonic episodes, each characterised by distinctive structural features. In each case, compositionally contrasted lithologies were affected in different ways. The rheological state of the whole complex is suggested to have varied during its evolution.
Torridonian volcanic sediments
Authors: Lawson D. E. 
Published: January 2010

Synopsis
Detailed evidence of volcanic activity within the Torridonian is provided for the first time. A distinctive sedimentary unit within the Stoer Group contains abundant angular volcanic fragments including pumice, shards and devitrified glass (interpreted as palagonite) which comprise from 40 to 80% of the sediment. The unit, which averages about 12 m in thickness, forms a significant marker horizon which can be traced some 50 km from Stoer southwest along the coast to Poolewe. Accretionary lapilli are the best indication of contemporaneity of volcanic activity with deposition of the unit. Their best development is at Coigach where they occur throughout 10 m of the upper portion of the unit which attains its maximum thickness here. This abundance, in combination with thickness, suggests that the eruptive source-vent was within several kilometres of Coigach.
Indications of geometry and areal extent are in the main limited to a section along the strike. Throughout most of the outcrop conformable stratigraphic relations exist with the underlying and overlying sediments. The sharp, clear-cut basal contact is an erosional surface, broadly planar with minor relief. At Stoer, however, the unit abuts and laterally intrudes a high (>3 m) bank of sandstones and mudstones, warping and contorting them and carrying away blocks as large as 2.5 m.
Irregular, branching, pipe-like segregations of pink authigenic feldspar (which originated during emplacement of the unit and in some cases are slightly post depositional but not unrelated in time) are of late vapour phase origin; some may represent fossil fumaroles.
This volcanic sediment horizon was deposited as an ash flow resulting from a highly explosive eruption of phreatic nature. Deposition occurred primarily in the shallow water, near-shore environment where conditions were favourable for local transition to hot lahars.
Sedimentology and palaeogeography of the Upper Old Red Sandstone in the Scottish Border Basin
Authors: Leeder Michael 
Published: January 2010

Synopsis
The Upper Old Red Sandstone of the southern Scottish Borders is a wholly fluviatile succession. The basal unconformity with the Silurian shows evidence of exhumed, ?pre-Upper O.R.S. topography.
Facies association 1 comprises fining-up cycles of sandstone and siltstone deposited by high sinuosity stream systems. Facies association 2 comprises fining-up cycles deposited by low sinuosity streams which may have been braided or non-braided. Facies association 3 comprises conglomerates, pebbly sandstones and sandstones deposited by low sinuosity, braided stream channels. Facies association 4 comprises thick sequences of thinly bedded sandstones, siltstones and conglomerates laid down in persistent flood basins.
Palaeocurrents show persistent stream flow from south west to north east and grain and pebble compositions are consistent with igneous and sedimentary sourcelands in Galloway. A gross upward trend to coarser, braided channel facies may have resulted from isostatic uplift in the hinterlands. The southern Border streams formed part of an interior drainage basin (Border Basin) with its centre to the north west of the present day Cheviot hills.
Granophyre pebbles in Tertiary conglomerate on the Isle of Canna, Inverness-shire
Authors: Emeleus C. H. 
Published: January 2010

Synopsis
Porphyritic granophyre pebbles in Tertiary conglomerate on Sanday, Isle of Canna, are identical with granophyre exposed in western Rhum. It is suggested that a west-flowing river, postulated by Geikie to account for features of the Canna conglomerates, received detritus from a tributary draining north-west Rhum. Porphyritic felsite associated with conglomerate on Compass Hill (Canna) may have been derived from eastern Rhum. The Tertiary lavas of Rhum, Canna and Sanday appear to be of distinctly later date than lavas on Eigg and Muck.
A gravity survey of the Cairnsmore of Fleet granite and its environs
Authors: Parslow G. R. , Randall B. A. O. 
Published: January 2010

Synopsis
A regional gravity survey of part of Galloway has defined two major negative anomalies, one centred over the Cairnsmore of Fleet granite and the other over Wigtown Bay. The former indicates that the granite probably continues to a depth of 11 km, has outward dipping contacts, and a sub-surface cupola-like protruberance to the south-west of the exposed portion of the massif. The gravity low in Wigtown Bay is thought to be indicative of an unexposed sedimentary basin which has a depth between 220 and 720 m. This basin extends in a north-westerly direction at least as far as the Cree estuary.
The offshore extension of the Loch Gruinart Fault, Islay
Authors: Dobson M. R. , Evans D. , Whittington R. 
Published: January 2010

Synopsis
A seismic survey has been carried out in the eastern Malin Sea between Colonsay, Islay and the Donegal coast of Eire, and has revealed the presence of major dislocations both to the north and south of Islay. These faults are considered to be the submarine extensions of the Loch Gruinart Fault. It is proposed that the Loch Gruinart Fault is connected to the Leannan Fault in the south-west and to the Great Glen Fault in the north-east. To the south-west of Islay, the fault forms the north-west boundary of a sedimentary basin in which about 1 km of sedimentary rocks (probably Permo-Triassic) is preserved; post-Palaeozoic fault movements appear to be dip-slip.
Lower Border Group (Tournaisian) stromatolites from the Northumberland basin
Authors: Leeder Michael 
Published: January 2010

Synopsis
Lower Border Group stromatolites contain detrital, micritic and calcareous algal filament laminae. Growth forms include domes, blisters, polygons, pillars, clubs, cusps, crinkles, bioherms and oncolites. Environments of growth are interpreted from comparisons with Recent stromatolites and from the evidence of associated carbonate lithofacies. Stromatolites in the Liddel Formation are often of intertidal origin and their outcrops mark the former northern shorelines of the Northumberland gulf sea. Seaward accretion of algal flats over shallow subtidal carbonate lithofacies gave rise to shoreline regressional sequences, now seen in vertical sections. Stromatolites in the Main Algal Formation are of shallow subtidal origin and accreted in central parts of the gulf sea.
Recent discoveries of Carboniferous fishes in Edinburgh
Authors: Wood S. P. 
Published: January 2010

Synopsis
A recent collection of fossil fishes from concretions in the Lower Oil Shale Group (Lower Carboniferous) of the Wardie Shore north of Edinburgh has enabled the fish-bearing strata, originally described as 70 ft of black shale, to be subdivided on characteristics of the concretions. Other horizons above and below these strata also yielded specimens. The numbers of various genera collected from these beds have been expressed as a table, which may form the basis for future studies on palaeoecology. The abundance of well preserved elasmobranchs is the most important result of this work, and may make necessary a reconsideration of the environment.
Petrochemistry of the Early Carboniferous (Dinantian) Lavas of Scotland
Authors: Macdonald R. 
Published: January 2010

Synopsis
This review is focussed on the early Carboniferous (Dinantian) stage of the complex Carboniferous-Permian volcanic cycle in central and southern Scotland (The “Midland Valley petrographic province”). Stress is particularly laid on aspects of the petrochemistry and petrogenesis not previously recognized or sufficiently discussed in the literature. The scarcity of analytical data for rocks from critical parts of the province means that much of the discussion must be of a preliminary nature; areas where further research is required are indicated.

The Dinantian lavas, dominated by a range of mildly undersaturated and hypersthene-normative (transitional) alkaline basalts, have associated nepheline or hypersthene-normative hawaiites, mugearites, benmoreites, quartz-trachytes and rhyolites. Several geographically distinct magmatic lineages are recognized, varying in such parameters as degree of silica undersaturation, Fe/Mg ratios and Na
2
O/K
2
O ratios at comparable values of differentiation index. TiO
2
and P
2
O
5
contents also vary from suite to suite.

The proportions of each lava type are variable in different areas, but three volcanic associations are rather arbitrarily distinguished; one showing a spectrum of rocks from ankaramitic basalt to trachytes and rhyolites: a second dominated by plagioclase-phyric basalts and hawaiites: and thirdly, an association consisting largely of olivine-clinopyroxene-phyric basalts, with more differentiated rocks scarce or absent. Though data are very scarce for post-Dinantian lavas, it is suggested that there has been a progressive change in basic magma chemistry with time during the Carboniferous, later alkaline magmas being increasingly silica-undersaturated. This change was accompanied by a change in the nature of the volcanism, which became more explosive, tuffs and agglomerates representing an increasing proportion of the eruptive products.
Some aspects of the petrogenesis of the Dinantian basic lavas are examined. A high-pressure (>10 kb) stage of fractionation variably involving clinopyroxene or olivine + clinopyroxene is required to explain the chemical variation in the basalts and hawaiites. More differentiated rocks may have evolved by crystal fractionation at lower pressures (within crustal magma reservoirs?) but insufficient data are available to test this hypothesis.
The age of the Allt na Cuile Sandstones (Upper Jurassic, Sutherland).
Authors: Brookfield M. E. 
Published: January 2010

Synopsis
New ammonite finds indicate that the Allt na Cuile Sandstones and overlying Loth River Shales range in age from at least basal Cymodoce Zone into the Mutabilis Zone (Kimmeridgian). These sediments differ markedly from the boulder bed facies of those zones to the north and south.
The Grampian Orogeny
Authors: Lambert R. St. J. , McKerrow W. S. 
Published: January 2010

Synopsis
Review of existing plate tectonic theories of the Lower Palaeozoic development of the north and northwest British Isles leads to the conclusion that ridge-trench impingement theory can be used to integrate all known geological observations within one unified plate tectonic theory for the area. Consideration of the consequences of the progressive impingement of a ridge-transform system with a northwesterly-dipping subduction zone in Arenig time gives explanations for: (a) termination of Dalradian sedimentation in the Arenig; (b) initiation of Barrovian metamorphism at the same time; (c) development and history of the Girvan-Ballantrae complex; (d) initiation of the Highland Boundary Fault as a dextral transform fault in the Arenig; (e) its absence in western Scotland; (f) the postulated presence of a boundary fault southeast of Connemara and perhaps at Pomeroy; (g) the peak of metamorphism (Barrovian and Buchan types) in the Dalradian and associated basic intrusions in the Arenig in both Scotland and Connemara; (h) the development of the Moine Thrust (and related foreland folds and thrusts) also in the Arenig and (i) the origin of the South Mayo trough on oceanic crust. Related events explained by this model include the location of the Donegal batholith, the generally low-grade metamorphism of Donegal and southwest Scotland, the location of the Great Glen Fault and all known faunal province and Ordovician sedimentological data from the Midland Valley and Southern Uplands. It is proposed that this Lower Ordovician sequence of related events be termed the Grampian Orogeny, distinct from the later Caledonian Orogeny, which is tectonically and geographically separate.
The paragenesis of spinel- and garnet-amphibole lherzolite in the Rodel area, South Harris
Authors: Livingstone A. 
Published: January 2010

Synopsis
The petrography and mineralogy of spinel- and garnet-amphibole lherzolites occurring in the granulite facies metasediments is described. Chemical analyses are presented for 7 lherzolites, 5 amphiboles, 5 orthopyroxenes, 3 clinopyroxenes, and a garnet. The spinel-amphibole lherzolites and chemically identical garnet-amphibole lherzolite conceivably represent spatially removed accumulates from the metagabbro-anorthosite complex. Garnet generation within the garnet-amphibole lherzolite and not the spinel-amphibole lherzolites is discussed, although both have probably been metamorphosed under identical conditions existing on the pressure-temperature boundary which separates the spinel and garnet lherzolite stability fields.
Seismic velocities in the Lewisian metamorphic complex, northwest Britain—‘in situ’ measurements
Authors: Hall J. , Al-Haddad F. M. 
Published: January 2010

Synopsis
Sixteen reversed seismic refraction profiles, each 1 km long, in Sutherland between Kylesku and Durness have demonstrated a difference in P-wave velocity between the northern and central belts of the mainland outcrop of the early Precambrian Lewisian rocks. The variably-retrogressed pyroxene granulites of the central belt (of andesitic-dioritic composition) yielded a velocity of 6.34 ± 0.17 km/s (6 observations); the quartzo-feldspathic gneisses of the northern belt yielded a velocity of 5.64 ± 0.18 km/s (6 observations); the rocks of the boundary region, near the Ben Stack line, yielded a velocity of 5.28 ± 0.23 km/s (4 observations). Correlations are made with the velocity layering of crustal models derived for the area, confirming the wide occurrence in the upper crust of granulite-facies rocks. Such high values of velocity in surface rocks place strict limits on velocity gradients in such rock types in the deeper continental crust.
A possible Lower Permian age for the onset of ocean floor spreading in the northern North Atlantic
Authors: Russell M. J. 
Published: January 2010

Synopsis
In the central and northern British Isles the Carboniferous period was marked by normal faulting, trough formation and alkali basalt vulcanicity typical of rifting environments. This tectonomagmatic activity may have been the precursor to the opening of the Rockall and Faeroe-Shetland troughs and a Norway-Greenland rift. The opening itself is held to have taken place shortly after the intrusion of the tholeiitic dykes and sills near the end of Carboniferous times, just as similar intrusions of Late Triassic age in eastern North America and West Africa heralded the opening of the southern North Atlantic. The newly formed upstanding continental margins slowly subsided partly by basin formation and partly by oceanward sagging finally permitting the Boreal ocean to flood a portion of northwest Europe in the Upper Permian.
Glacial Geomorphology of the Dulnain Valley, Inverness-shire
Authors: Young J. A. T. 
Published: January 2010

Synopsis
Moulding of bedrock, excavation of glacial breaches and carry of erratics indicate that a major ice sheet overran the Dulnain valley from the S and W. The ice sheet later wasted away, releasing meltwaters that cut glacial drainage channels and deposited eskers, kames and kame terraces whose distribution enables reconstruction of the deglaciation. Glacial drainage was concentrated on the northern side of the valley and was augmented by exotic meltwaters that flowed into the Dulnain valley at numerous locations across its northern watershed. As the ice sheet downwasted, the regional SW–NE flow of ice-directed meltwaters was disrupted by the underlying topography which increasingly influenced the courses followed by the glacial rivers. Meltwaters progressively sought out more direct downhill routes, but were unable to penetrate the ice mass completely until the later stages of deglaciation.
Petrotectonic environments of the Girvan-Ballantrae lavas from rare-earth element distributions
Authors: Lewis A. D. , Bloxam T. W. 
Published: January 2010

Synopsis
Rare-earth element abundances and distribution patterns in Arenig tholeiitic pillow lavas from the Girvan-Ballantrae ophiolitic complex, Ayrshire, are similar to those of mid-ocean ridges and island arcs. Rare-earth evidence alone does not distinguish between these two possibilities, but the thickness of the Arenig lavas is much greater than that of typical mid-ocean ridges and more comparable with island arc series. The absence of a sheeted dyke complex also supports this conclusion. The Caradocian pillow lavas have rare-earth element patterns resembling oceanic island (Hawaiian-type) tholeiites while others have more strongly enhanced light rare-earth abundances typical of continental tholeiites.
Polyphase generation of nappe structures in the Dalradian rocks of the southwest Highlands of Scotland
Authors: Roberts John L. , Treagus Jack E. 
Published: January 2010

Synopsis
A regional synthesis of the Dalradian structures in the South-west Highlands of Scotland is attempted, based on the conclusion that the Iltay Boundary Slide passes into the Ballachulish Slide as it is traced around the Glen Orchy Antiform and the Stob Bhan Synform. On this framework the primary and secondary folds are traced throughout the South-west Highlands within the constraints imposed by the stratigraphy and structural knowledge. The primary folds associated with the development of the Tay Nappe at a high structural level are themselves affected by secondary folds at a deeper level. These folds define the Glen Orchy Nappe with an amplitude exceeding 25 km, underlying the Tay Nappe. The primary structures are traced through the secondary structures to root at depth within the Moine rocks lying between the Glen Orchy Antiform and the Kinlochleven Antiform. It is concluded that the polyphase development of nappes in the SW Dalradian is essentially a superficial phenomenon.
The petrology of the Dippin sill, Isle of Arran
Authors: Gibb F. G. F. , Henderson C. M. B. 
Published: January 2010

Synopsis
The Dippin sill, which is emplaced into the Triassic sediments of SE Arran, is a basic alkaline intrusion of Tertiary age within which four main rock types have been identified. Examination of vertical sections through the sill, including two drill holes, indicates that it consists essentially of a thick central crinanite unit bordered by thin marginal teschenite facies with minor units of augite teschenite and basic pegmatite occurring at various levels. The compositions of crinanites, marginal teschenites and augite teschenites plus pegmatites define three distinct chemical trends which formed during a complex continuous differentiation and emplacement process. This process began with the intrusion of a mantle-derived, alkaline, basic magma into a deep crustal reservoir. Crystallization and gravitational settling of olivine and plagioclase resulted in the magma becoming compositionally stratified. Relatively fractionated magma was subsequently expelled from the top of this reservoir and intruded at a shallow depth to form the marginal facies of the sill. This was followed by the main intrusion of less fractionated olivine-bearing magma to form the thick central portion of the sill. Further differentiation occurred during and after the uprise and emplacement of these magmas resulting in the evolution of the three distinct trends.
Deformation of the Belhelvie Mass, Aberdeenshire
Authors: Boyd R. , Munro M. 
Published: January 2010

Synopsis
Evidence of shearing and mylonitization has been found to occur widely within and around the body of mafic and ultramafic igneous rocks that forms the Belhelvie intrusion. It is inferred that the original relations of these rocks were greatly disturbed when this deformation occurred and that the igneous mass has been largely detached from the country rocks into which it was emplaced and now has a complex structure. This disruption appears to have mainly occurred within 30 m.y. of the emplacement of the magma, but does not seem to be simply related to the development of the Buchan Anticline, the major, post-magmatic structure that earlier workers envisaged as occurring in this area.
The most recent glaciation of the Orkney-Shetland Channel and adjacent areas
Authors: Flinn Derek 
Published: January 2010

Synopsis
During the most recent glaciation Shetland was covered by an ice cap which flowed radially outwards from the islands, but was deflected in the SW so that it flowed in a northwesterly direction across Foula and in a southeasterly direction across Fair Isle. This pattern indicates that a flow to the SW from Shetland was blocked, possibly by a mass of ice lying over Orkney, but that there was no hindrance to flow towards Norway on the E side of Shetland. In the North Sea to the E of the Moray Firth there was an ice free area. Thus there is no evidence for a Scandinavian ice sheet in the area and consequently no reason for the deflection of Scottish ice from the Moray Firth to the NW across Orkney. It is suggested that the Scandinavian ice sheet covered the North Sea and deflected the Scottish ice across Orkney during the previous glaciation, but that in the last glaciation it did not cross the Norwegian Trench.
The late Quaternary climatostratigraphy of IGS Borehole SLN 75/33 and its application to the palaeoceanography of the north-central North Sea
Authors: Gregory Diane , Harland Rex 
Published: January 2010

Synopsis
The dinoflagellate cyst and benthonic foraminiferal analysis of the Quaternary sediments of borehole SLN 75/33 in the central-northern North Sea has resulted in the formulation of a climatostratigraphy which is believed to encompass sediments ranging in age from Ipswichian (Eemian) to Recent. Since the areal distribution of the organisms involved is thought to be controlled by water mass, an oceanographic history is attempted for the late Quaternary of the North Sea. This involves the penetration of North Atlantic water and the establishment of a homothermal water mass which allowed high percentages of “species of southern origin” into the area at times of strong climatic amelioration, and the loss of a North Atlantic influence during periods of climatic deterioration. Weaker ameliorations are more difficult to interpret but probably relate to some influence of North Atlantic water and a slight increase of water temperatures in relation to times of climatic deterioration, allowing only low percentages of “southern forms” into the area.