bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metamorphic index minerals in the eastern Dalradian
Authors: Porteous W. G. 
Published: January 2010

Synopsis
The geographical distribution of the minerals kyanite, andalusite, chloritoid, staurolite, cordierite (and garnet) in the eastern Dalradian is discussed in the light of their pressure–temperature relations. It is established that major regional features of index mineral distribution, such as the westerly restrictions of the chloritoid zone, can be explained solely in terms of pressure–temperature variations. A close correspondence between the map and the pressure–temperature grid is illustrated, and the transitional nature of the boundary between the Buchan and Barrovian zonal sequences is emphasized.
The Quaternary in Scotland: a review
Authors: Sissons J. B. 
Published: January 2010

Synopsis
Only two interglacial pollen sites are known in Scotland, both in Shetland. There is at present no satisfactory evidence that the decay of the last ice-sheet was interrupted by a significant readvance. Decay was probably complete by 12 500. The Loch Lomond Readvance, which probably began before 10 800, is associated with excellent end moraines (often, significantly, multiple) at more than 100 locations. Former firn lines can be calculated and palaeoclimatic inferences made. The mapped limit of the readvance accords with the distribution of 58 lateglacial pollen sites. Periglacial processes currently operate on the Scottish mountains but were extremely active during the Loch Lomond Readvance, when permafrost (with frost wedges) existed down to sea-level. A summary of the sequence of lateglacial and postglacial sea-level changes (especially in the southeast) includes re-dating of the low-level rock platform and cliff of western Scotland and leads to an unconventional mode of deglaciation for the Glasgow area.
The stratigraphy of late Precambrian metasediments between Glen Roy and Lismore
Authors: Hickman A. H. 
Published: January 2010

Synopsis

The Moinian and Dalradian stratigraphy of the Glen Roy-Lismore area is systematically described and its terminology and definition is revised. The highest formation of the succession, the Lismore Limestone Formation, is of Lower Dalradian age and stratigraphically underlies the Portaskaig Boulder Bed.

Succession, Glen Roy-Lismore.
Thickness
Islay

Middle Dalradian

Portaskaig B. B.

LOWER DALRADIAN
Ballachullish Group
Lismore Limestone Fmn.
~1200 m
Islay Limestone Fmn. (lower part correlated with Lismore Limestone Fmn.)

Cuil Bay Slate Fmn.
300 m

Appin Phyllite Fmn.
250 m

Appin Limestone Fmn.
150 m

Appin Quartzite Fmn.
300 m

Ballachulish Slate Fmn.
400 m

Ballachulish Limestone Fmn.
250 m

Lochaber Group
Leven Schist Fmn.
~2000 m

Glen Coe Quartzite Fmn.
400 m

Binnein Schist Fmn.
400 m

Binnein Quartzite Fmn.
300 m

Eilde Schist Fmn.
400 m

Eilde Quartzite Fmn.
600 m

Moinian
Eilde Flags Fmn.
>1000 m

At Loch Leven the Lochaber Group is 4 km thick and the entire Lower Dalradian succession 7 km thick. To the north and west the quartzite units wedge out and the succession thins to about 5 km. This regional disparity is attributed to major facies changes and not structural modification as previously maintained (Bailey, 1934). There is a sedimentary contact between the Moinian and Dalradian Assemblages across most of the area.
A detailed geological map of Lismore Island is presented together with a stratigraphic table of the Lismore Limestone Formation, which comprises a thick, partly cyclical sequence of alternating limestones and slates.
The Eilde Flags Formation, the Lochaber Group and the Ballachulish Group constitute three lithological associations, each diagnostic of particular depositional conditions within a shallow shelf sea environment.
The chemical compositions of the limestones and slates are tabulated and briefly discussed.
Variations in basalt chemistry with time in the Midland Valley province during the Carboniferous and Permian
Authors: Macdonald R. , Thomas J. E. , Rizzello S. A. 
Published: January 2010

Synopsis
New chemical data for lavas from the sequences at Burntisland, the Bathgate-Linlithgow Hills, the Passage Group succession of Ayrshire, Mauchline and Thornhill are used to examine changes in chemistry of basic magmas emplaced in the Midland Valley petrographic province during the Carboniferous and early Permian. These lava groups contain basic magma types not yet recorded from the earlier Dinantian suites, especially moderately to strongly silica-undersaturated varieties.
The Carboniferous-Permian alkaline magmatism is related to two thermal cycles, each of which produced a similar trend of magma compositions (towards increasing silica-undersaturation) with time; one cycle was early Dinantian to early Namurian, the other mid-Namurian to early Permian in age. Each cycle developed, however, under different tectonic conditions.
Layered ultramafic rocks within the Borralan Complex, Scotland
Authors: Matthews D. W. , Woolley A. R. 
Published: January 2010

Synopsis
Ground magnetic survey has delineated a 5000 γ anomaly over part of the south-western margin of the Borralan Complex. Drilling across the anomaly has revealed a suite of pyroxenites, cromaltites, and hornblendites similar to rocks known at outcrop and in addition olivine-, phlogopite-, diopside-, and tremolite-rich rocks not hitherto known from Borralan. Whole rock chemistry indicates a similarity to several other complexes. While textural and lithological evidence, including fine-scale layering, support a cumulus igneous origin for the pyroxenites, hornblendites, and olivine rocks, some or all of the other types are most probably due to metasomatic processes near the contact with marble.
Deformation around the Beinn an Dubhaich granite, Skye
Authors: Longman C. D. , Coward M. P. 
Published: January 2010

Synopsis
The Beinn an Dubhaich granite intrudes and deforms Cambro-Ordovician limestones and Tertiary dykes in west-central Strath on Skye. The limestones were intensely deformed by radial compression from a centre at the west end of the present granite outcrop, presumably due to the forceful intrusion of an early phase of the granite. Basaltic dykes associated with the Tertiary igneous centres of Skye were deformed co-axially with the earlier deformation in the limestones. Chilled boudin necks in the dykes suggest that this deformation took place before consolidation of the basalt. This was followed by passive intrusion of the main mass of the granite as a large, possibly funnel-shaped sheet.
The structure of NE Islay
Authors: Fairchild Ian J. 
Published: January 2010

Synopsis
The first phase of Caledonian deformation in NE Islay produced open folds with axial planar cleavage. At one locality two sub-phases of deformation are recognized. A probable syn-tectonic fault, the Bolsa Fault, is described. The Islay Anticline is a sinistral en-echelon anticlinorium whose axial region approximately parallels the Loch Skerrols Thrust.
Faulting and associated cataclasis in Eastern Ardgour
Authors: Stoker M. S. 
Published: January 2010

Synopsis
Three main sets of faults have been identified in Eastern Ardgour, the NE–SW faults, the NW–SE to W–E faults and the N–S faults. Each set has formed in response to a specific tectonic regime. Cataclastic rocks associated with the faults fall into two main series, the protomicrobreccia–microbreccia–cataclasite–ultracataclasite series, and the fault breccia–fault gouge series. These rock types are abundant in the hills and along the north-west shore of Loch Linnhe, but their distribution is far from uniform. The most intense cataclasis occurs along or adjacent to the main faults of the area which themselves lie within broader zones of variably shattered rock.
A history of fault activity has been established for the area; of particular interest are the NE–SW faults because they form part of the Great Glen fault zone. Study of these faults and their associated cataclastic rocks indicates that the Great Glen has been active, intermittently, as a brittle seismic fault zone since late Caledonian times.
Blocks of marine clay in till near Helensburgh, Strathclyde
Authors: Browne M. A. E. , McMillan A. A. , Hall I. H. S. 
Published: January 2010

Synopsis
An occurrence of till containing two large blocks of shelly marine clay is described. Radiocarbon dates on shells from the smaller block suggest that the till formed during the Loch Lomond Stade, although the locality is outside the conspicuous terminal moraine of the Loch Lomond glacier. The origin of the till is discussed.
The bathymetry and sedimentology of Loch Benachally, Perthshire
Authors: Al-Bayati K. M. , McManus J. 
Published: January 2010

Synopsis
During recharting of Loch Benachally echograms revealed an echostratigraphy which is compatible with lacustrine silts resting on till. Construction of an isopach map permitted the volume of post-glacial sediment to be estimated. After making allowance for water and organic contents and reservoir trap efficiency, catchment sediment yields of 0.62 cm per 1000 years are obtained for mineral matter alone.
Field relations in the north-eastern part of the Insch mafic igneous mass, Aberdeenshire
Authors: Leslie A. G. 
Published: January 2010

Synopsis
A total field ground magnetic survey, supplemented by a programme of bedrock exposure in shallow pits, has enabled considerable revision to be made to the position of the north-eastern margin of the Insch mass. In addition the distribution and attitude of the basic igneous rocks and their associated hornfelses and the nature of the external contact is shown to be strongly influenced by zones of shearing deformation trending between E–W and NE–SW.
Magnetic modelling has shown that the external contact of the mass, and the igneous rock units within the mass dip steeply (60°–70°) southwards, and that the igneous rocks are limited to a depth of about 5 km. New petrological information indicates that narrow but discrete zones of hornfelsed derivatives of the schistose and gneissose country rocks exist, and that major trends and discontinuities observed on the magnetic map correlate with zones of shearing and mylonitization which generate the complex distribution of the basic mass and its country rocks. The external contact is rarely undisturbed. Field relations in NE Scotland indicate a regionally important episode of shearing deformation about 470 Ma in age. Later faulting on NNW-SSE or NW-SE trends has further contributed to the disruption of the basic mass and its environs.
Sedimentation and tectonics in the Scottish Dalradian
Authors: Anderton Roger 
Published: January 2010

Synopsis
Sedimentological research on the Scottish Dalradian has progressed from the recognition of sedimentary structures in the 1930s, via the identification of sedimentary facies from the 1950s onwards, to the integration, in the 1970s, of sedimentological data with that from studies of stratigraphy, tectonics and volcanism. This has now led to an understanding of the pre-orogenic evolution of the Dalradian terrane in terms of progressive lithospheric stretching associated with the break-up of the Proterozoic Supercontinent.
The Appin and Argyll Groups were deposited on the NW side of a late Precambrian marine gulf which developed over a complex zone of crustal thinning between the Laurentian and Baltic parts of the Super-continent. As extension accelerated, subsidence rates increased and the Dalradian area of the gulf evolved from a relatively shallow shelf into a series of turbidite basins. Thinning of the lithosphere gave rise, in Argyll Group times, to locally intense igneous activity. Subsequently, complete continental rupture along the gulf axis led to the birth of the Iapetus Ocean. By Southern Highland Group times the Dalradian terrane had become part of the new, thermally-subsiding, Laurentian continental margin.
One can envisage the geometry and facies variations of many horizons within the Dalradian in terms of a pattern of numerous fault blocks defined by listric normal faults, dipping SE towards the site of continental rupture, and NW–SE trending transfer faults, which divided the gulf and subsequent margin into a series of compartments. It was movements on these faults that largely controlled Dalradian stratigraphic evolution. For example, pulses of rapid stretching, and consequent fault activity, produced basin-deepening sequences which mark the base of the Easdale and Crinan Subgroups.
Lithofacies and stratigraphy of a Dinantian non-marine dolostone from the Lower Oil-Shale Group of Fife and West Lothian.
Authors: Maddox Steven J. , Andrews Julian E. 
Published: January 2010

Synopsis
A Dinantian Lower Oil-Shale Group sedimentary rock sequence from Colinswell in the Burntisland district of Fife contains sandstones, shales and carbonate rocks. From facies analysis the sandstones are interpreted as proximal deltaic channel-mouth bars whilst the shales and carbonates represent low-salinity interdistributary bay facies. One distinctive dolostone unit which is laminated and brecciated is interpreted as a former stromatolitic mudflat which underwent subaerial exposure and desiccation. Given the general stratigraphic position of this sequence between the established marker horizons of the Burntisland Marine Band (= Pumpherston Shell Bed) and the Burdiehouse Limestone, rocks of similar age, the Queensferry Beds, were studied at outcrop in West Lothian. At both South Queensferry and Hopetoun (West Lothian) a remarkably similar dolostone unit to that at Burntisland was identified within the Queensferry Beds. It is proposed that these dolostone beds are lateral equivalents, formed during a basin-wide ‘regressive event’. Correlation of the dolostones not only improves the local Lower Oil-Shale Group stratigraphy, it provides a time marker from which to analyse local facies variation in the underlying and overlying delta-derived sandstones.
Rare earth element geochemistry of Lewisian grey gneisses from Gruinard Bay
Authors: Fowler M. B. , Plant J. A. 
Published: January 2010

Synopsis
Previous work has suggested that Lewisian grey gneisses from Gruinard Bay suffered hornblende-granulite sub-facies Badcallian meta-morphism, during which depletion of the large-ion lithophile elements (K, Rb, U and Th) proceeded to a degree intermediate between amphibolite-facies and pyroxene-granulite-facies counterparts. Rare earth element data for the gneisses are presented here, and used to test current theories of Lewisian petrogenesis, including the processes responsible for the observed LILE depletion. Intracrustal partial melting—as recently applied to the type Scourian pyroxene-granulites—is shown to be inappropriate to the specific conditions leading to an amphibole-bearing (hornblende-granulitic) residue, such as that required at Gruinard Bay. On the other hand, hydrous melting of Archaean tholeiite, retaining a mineralogically variable eclogitic residue, is apparently capable of accurately reproducing the REE patterns of the gneiss suite, especially when coupled with local amphibole fractionation. This model requires a subsequent phase of LILE loss during metamorphism.
Anorthosite xenoliths in Loch Maree Group meta-basalts
Authors: Cattell Alan , Williams Patrick 
Published: January 2010

Synopsis
Ellipsoidal bodies of plagioclase (lenticles), up to a metre long, occur within meta-basalts of the Loch Maree Group. They outcrop to the north-east of Loch Maree, but not in the better known Gairloch Schist Belt. The lenticles are contained within a strike-parallel belt of amphibolite (metamorphosed tholeiitic basalt). The lenticle bearing unit lies within lenticle free units of similar or slightly more fractionated composition.
The form and mineralogy of the lenticles is controlled by the metamorphism and deformation that they and their basic host have undergone; the mineralogy is amphibolite facies, partly retrogressed to greenschist, the lenticles are now prolate ellipsoids with long axes parallel to a mineral lineation in the host. The composition, petrology and field relations of the lenticles are consistent with their being xenoliths of anorthosite, and inconsistent with other possible origins for Ca and Al rich rocks. The lenticles are indistinguishable in composition from the early Proterozoic South Harris Anorthosite, and it is concluded that they were derived from a body of similar age and type. This body may represent an early part of the Loch Maree magmatic event. The association of anorthosite with the Loch Maree Group indicates a similarity to other supracrustal-anorthosite associations within the Lewisian (South Harris, Ness Complex of northern Lewis, Iona).
The Geikie igneous centre, west of Lewis: its structure and influence on Tertiary geology
Authors: Evans D. , Abraham D. A. , Hitchen K. 
Published: January 2010

Synopsis
The Geikie igneous centre is identified from a large positive gravity anomaly to the west of Lewis. The anomaly is satisfied by a simple two cylinder model with a maximum diameter of 26 km. The centre is covered by Palaeocene basalts which are domed and radially disposed around it. The centre occurs near the apex of a topographic bulge on the slope west of Scotland which overlies thinned crust. The intrusion has had a marked influence on the Tertiary development of the area, principally because it deflected faulting/flexuring associated with Eocene subsidence of the Rockall Trough to a zone seaward of the intrusion. Subsequent subsidence of the basalt and overlying Tertiary sediment wedge has been hinged at the transition between normal and thinned crust to the east of the centre. The curved bathymetric Geikie Escarpment is not faulted, but is an eroded feature cut into Oligocene sediments on this subsiding wedge.
Geochemistry, provenance and palaeoclimate of the Sleat and Torridon groups in Skye
Authors: Stewart A. D. 
Published: January 2010

Synopsis
Arkoses of the Sleat and Torridon groups in south-east Skye form a continuous succession 4500 m thick. Palaeocurrents came from the west. The source rocks were hornblende-biotite-gneisses, granite or granite-gneisses, quartzose sediments and acid volcanics, all with upper crustal geochemical signatures. Detritus from the basic gneisses predominates in the lowest sediments, but is gradually replaced by granitic material stratigraphically up the succession.
The lowest sediments accumulated in palaeovalleys with a relief of <200 m. They retain the geochemistry of the parental basic gneisses which formed the local basement. Subsequent rifting brought sediments tens of kilometres from the west, some from as far as the flanking highlands, where acid rocks were common.
The climate was initially arid. But the development of rift highlands attracted rainstorms, and the higher runoff leached Ca from hornblende as it weathered to chlorite. Small amounts of Na may also have been lost from plagioclase during weathering. The ratio of material transported in solid form to that in solution is estimated to lie in the range 15–20 for the lowest formation, but to have been <10 higher in the succession. By analogy with very large modern catchments, this suggests latitudes of 22–40 deg. Palaeolatitudes of 30–45 deg. have been deduced for the Torridon Group on the mainland of Scotland, using palaeomagnetism.
Fault displacements in the Dalradian of the Central Highlands
Authors: Treagus J. E. 
Published: January 2010

Synopsis
Existing map data across the five principal faults affecting the Dalradian of the Central Highlands have been examined to determine fault displacement history. The displacement of the axes and axial-traces of major folds show that each fault has suffered a significant component of dip-slip which leads to a reduction in the amount of the much-quoted sinistral strike-slip component. A consideration of the displacement of igneous bodies suggests that some of these have been emplaced between an early dip-slip movement and a later dominantly strike-slip movement. The Ericht Fault was probably re-activated with the initiation of the Pass of Brander Fault as part of the Etive ring-faulting. Faulting is considered to have started in the waning stages of the ductile folding of the Grampian Orogeny and significant displacements to have finished before the eruption of the late Silurian Lorne Lavas.
Red tuffs in the Palaeocene lava successions of the Inner Hebrides
Authors: Emeleus C. H. , Allwright E. A. , Kerr A. C. , Williamson I. T. 
Published: January 2010

Synopsis
Thin, sharply defined red deposits in the Palaeocene lava successions of the Inner Hebrides are interpreted as tuffs. They commonly contain plagioclase and augite, or in some instances, sanidine, aegirine-augite, amphibole, biotite and titanite; lithic fragments include basalt and, less commonly, trachyte and pumice, and even rarer glass. They contrast with the contemporaneously weathered and deeply decomposed, reddened lateritized, tops of lava flows that grade down into dark-coloured lava. The tuffs provide stratigraphical markers of at least local use and at some localities their distinctive petrography and mineralogy records magmatism not preserved in the contiguous lavas. The recognition that some of the inter-lava red beds are tuffs rather than laterites may imply a reduction in the time required for the lava successions to form.
Roscoelite associated with reduction spots in Devonian red beds, Gamrie Bay, Banffshire
Authors: van Panhuys-Sigler Michèle , Trewin Nigel H. , Still John 
Published: January 2010

Synopsis
Roscoelite, a vanadium mica, occurs in the cores of reduction spots within the Lower Old Red Sandstone that crops out in Gamrie Bay (Moray Firth). The finely crystallized mineral is seen both as a cement in the sandstone and replacing plagioclase feldspar in a lithic clast of granitic composition. It is suggested that roscoelite was formed by a complex reaction involving a change in the oxidation–reduction potential of the groundwater and the presence in the sandstone of sensitive associations of minerals containing vanadium-rich iron and titanium oxides. The reduction spots formed by diffusion as part of the same process.
Origin of the ‘Berwick Monocline’: geometrical and geophysical considerations
Authors: Roper H. 
Published: January 2010

Synopsis
Analysis of minor fold vergence and thrust directions in Carboniferous strata at Sea House, north Northumberland, has revealed the synclinal member of a major monoclinal fold pair and thus established the easterly vergence of the southern sector of the Berwick monoclinal disturbance or ‘Berwick Monocline’, a discrete NNW-SSE structure on the western shore of the North Sea. The most intense deformation within the Berwick structure is found in its central sector, where displacement on the steep east-directed Boundary reverse fault is about 0.5 km; the footwall is, however, almost undeformed, and extends offshore as the Marshall Meadows flat zone. The Berwick disturbance as a whole is arcuate in plan, the concave side facing east.
The association of a weak gravity anomaly low with higher amplitude aeromagnetic anomalies over the Marshall Meadows flat zone is explained by postulating a concealed anomalous basement massif, the Marshall Meadows block, in which a low density, possibly granitoid core is associated with a locally more strongly magnetized margin. The marked attenuation of Dinantian strata in the Marshall Meadows flat zone is consistent with lower density and consequent positive buoyancy of the underlying Marshall Meadows block as compared with adjacent basement.
A few tens of kilometres south of the Berwick ‘Monocline’, between Holburn and Lemmington, the Carboniferous cover rocks are affected by a pair of monoclinal structures. Their combined geometrical relationship (location, trend, extent, vergence and arcuate form) t o the adjacent granite-cored Cheviot block is comparable with the relationship of the Berwick structure to the postulated Marshall Meadows block.
It is suggested that during regional east-west shortening the Berwick and Holburn/Lemmington structures formed in response to contrasts in the Caledonian basement between the stronger, less dense igneous rocks of the Cheviot and postulated Marshall Meadows blocks, and the adjacent weaker, denser Silurian shale and greywacke host rocks.