bluuebunny/crossref_metadata_2025 huggingface dataset:
The ground moraines of Midlothian and East Lothian
Authors: Kirby R. P.
Published: January 2010

Synopsis

Three separate depositional units are described from the Esk and upper Tyne basins. Each unit comprises a till grading upwards into glacio-fluvium. The tills from the basal and middle units together correspond to what has previously been described as the Basal Boulder Clay of the area. Stone counts suggest the basal till was derived from a westerly quadrant. The high proportion of greywacke in the intermediate till suggests it was derived from a southerly quadrant.

The topmost depositional unit is represented chiefly by the Roslin Till, previously described as the Southern Upland Readvance Boulder Clay. This till is confirmed as the product of a local glacial readvance, but the stone count throws doubt on the former assumption that this readvance was from the Southern Uplands.

No organic material is known to occur between the three depositional units. Mechanical analyses do not serve to distinguish the three tills.
Volcanic sediments, stratigraphy and tectonic background of the Old Red Sandstone of Kintyre, W. Scotland
Authors: Friend P. F. , MacDonald R.
Published: January 2010

Synopsis

The Lower Old Red Sandstone of southern Kintyre is divided into three formations. The aggregate thickness (excluding the island of Sanda) is 1200 m. Breccias, conglomerates and sandstones are described which are similar to those of Arran. Also described are pyroclastic sediments, which are kaolinitic.

Three volcanic vents in the Southend region have been re-investigated and are thought to illustrate three stages in the same sequence of igneous activity. The composition of the sediments and palaeocurrent observations show that the sediment was derived from the north or north-west. The thickness of the Lower Old Red Sandstone succession is compared with that of other successions in the Midland Valley, and the differences are explained in terms of the geometry of crustal movement. The position and nature of the Highland Boundary Zone is briefly discussed. It is suggested that it extended across southern Kintyre during Lower and Middle Devonian times as a relatively broad zone of southward down-warping.
Analysis of a mica subfabric
Authors: Keppie J. D.
Published: January 2010

Synopsis

The mica (muscovite, biotite, and/or phlogopite) in the Lewisian rocks near Furnace, Loch Maree, exhibits two habits, phylloblastic and decussate nemato-blastic crystals, which are deduced to have grown during one period of deformation and metamorphism called main phase. All the micas, along with the associated mesoscopic fabric elements, are deformed by two subsequent periods of deformation, mid phase and late phase, during which no recrystallisation of mica occurred. These observations are supplemented by a petrofabric analysis, the interpretation of which involves the interplay of various factors: Schnitteffekt, the amount of minerals other than mica in the rock, the influence of active and passive s-planes versus the crystal boundary effect and interfacial tension, the degree of mid phase deformation, and the composition of the mica; all of these combine to produce the mica subfabric. The effect of late phase deformation on this subfabric is negligible within the area. On this evidence the age dates obtained by Giletti, Moorbath, and Lambert (1961) on two muscovite samples from this area—1510±40 m.y. and 1540±45 m.y.—represent the latter part of the main phase metamorphism, thus placing it in the Laxfordian orogeny.
Structure and metamorphism of the Lewisian of east Tiree, Inner Hebrides
Authors: Westbrook Graham K.
Published: January 2010

Synopsis

A study of the Lewisian of east Tiree has shown the presence of previously unmapped psammitic, calcareous and semipelitic paragneisses which occur, often with basic gneisses, in the ‘grey gneiss’ of the area. Four main phases of folding have been determined: F
1
—isoclinal intrafolial folds; F
2
—tight similar folds; F
3
—close and open folds with NW.–SE. axial planes; and F
4
—open and gentle folds with NE.–SW. axial planes. Fold phases (F
1
–F
3
) have been related to successive metamorphic episodes of granulite facies, upper amphibolite facies and lower amphibolite facies which have been assigned to the Scourian, Early and Late Laxfordian respectively on the basis of their structural relationship with intrusive basic bodies which are now amphibolites.

The relations of the ‘grey gneiss’ to the paragneisses and basic gneisses suggest the existence of a pre-Scourian basement. The region is cut by late shears associated with the formation of pseudotachylite.

The sequence in Tiree is related to the structural and metamorphic sequences given by other authors for the Outer Hebrides.
The composition of some kyanite-bearing regionally metamorphosed rocks from the Dalradian
Authors: Atherton M. P. , Brotherton M. S.
Published: January 2010

Synopsis

In the Dalradian of Scotland kyanite is confined to pelites with: (a) M/FM (mol. MgO/FeO + MgO) values greater than 0.540; (b) M/FM values below 0.540, but where the ‘available’ or matrix composition, from which the kyanite grew, had an M/FM value exceeding 0.540, due to the removal of FeO from the reacting system. This occurs in rocks with large amounts of refractory garnet or in rocks containing ore minerals whose composition is determined by the ambient oxygen content of the rock. The values for the regional Dalradian pelites are consistent with those found previously for the growth of kyanite in aureole rocks from Donegal, Eire, but in this case a model of ‘available’ composition, as well as the total rock composition has to be considered.
Stratigraphy and structure of Upper Dalradian rocks at the Highland Border
Authors: Harris A. L. , Fettes D. J.
Published: January 2010

Synopsis

Relationships between Dalradian slate and grit formations at Dunkeld, Callander and Aberfoyle are discussed. It is concluded that whereas slates at Aberfoyle lie in the core of a primary fold (the Aberfoyle Anticline), those at Dunkeld lie on the limb of such a fold and are flanked by grits which are respectively younger and older than the slates. At Callander the slates occupy the core of a major synform which has folded already inverted beds.

Since the slates at the Highland Border lie in different structural settings at separate localities their equivalence cannot be readily accepted as hitherto. Consequently, the grit bands which flank the slate bands can no longer be readily correlated over great distances. Correlation of the Lower Cambrian Leny Limestone bands along the Highland Border also becomes less convincing.
Tectonic control of sedimentation at the margin of a Carboniferous depositional basin in Kirkcudbrightshire
Authors: Deegan C. E.
Published: January 2010

Synopsis

The stratigraphy and sedimentation of the Lower Carboniferous rocks between White Port and Kirkbean, Kirkcudbrightshire have been re-investigated. The sediments fall into two distinct associations (i) light hued, fine-grained carbonate-rich rocks deposited by normal shallow marine and fluviatile agencies and (ii) red beds dominated by coarse conglomerates and deposited predominantly under sub-aerial conditions.

Within the red bed association there are at least two large-scale cycles of deposition commencing with coarse alluvial conglomerates, fining upwards into subordinate shallow marine fossiliferous sediments and then coarsening upwards into alluvial conglomerates again. The origin and preservation of these cycles is related to penecontemporaneous activity on a large basin margin fault, possibly aided by late–Caledonian upward movements within the Southern Uplands.
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 petrology of quartzite breccias from an early linear vent, Glen Coe, Argyll
Authors: Hardie W. G.
Published: January 2010

Synopsis

The petrology of two Lower Old Red Sandstone breccias associated with an early linear vent (Hardie 1968) is described. The vent, much of which is covered by later rhyolite originating elsewhere, is occupied by a pyroclastic breccia containing abundant fragments of quartzite as well as acid trachyte fragments. This is the first record of trachyte in the area, and chemical analyses show that it is unusually rich in potash (K
2
O 10–11%). The second breccia consists entirely of quartzite and has been mapped as explosion–breccia. It occurs as relatively short dykes, most of which line the vent wall.
The structure and structural dating of the Carn Chuinneag intrusion, Ross-shire
Authors: Shepherd J.
Published: January 2010

Synopsis

The Carn Chuinneag intrusion is a foliated granite pluton emplaced in the Moine rocks of the Northern Highlands of Scotland, containing large irregular inclusions of amphibolite. Minor sheet-like apophyses at the margin of the pluton extend into the Moine country rocks. The emplacement occurred after
D
1
in static conditions and the Moinian envelope was distended. Structure contours suggest that the intrusion was originally a sheet-like pluton about 4 km (2.48 miles) thick.
D
1
structures which are ubiquitous in the Moinian over a wide area surrounding the granite are entirely absent from the pluton. The widespread foliation of the pluton and sheet-like apophyses is equivalent to
S
2
in the Moine rocks, and it is folded by major and minor scale
D
3
folds closely similar in style to
D
3
folds developed in the Moinian both inside and outside the granite aureole.
D
4
deformed the whole of the pluton and its Moinian envelope.
D
1
and
D
2
structures of the Carn Chuinneag area and the Moine Thrust belt at Loch Eriboll are considered to be correlatives. Thus, pre-granite
D
1
structures are inferred to be post-Arenig in age.
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.
Fluvial sediments entering the Tay Estuary: sediment discharge from the River Earn
Authors: Al-Ansari N. A. , McManus J.
Published: January 2010

Synopsis

In the first in a series of studies of sediment transport into the Tay Estuary, the directly measured and indirectly estimated sediment loads passing two gauging stations are compared. Discharges of 154 000 tonnes per year pass the lowests station, and 98% of this is in suspension. None of the used indirect methods of calculating the load yields the measured discharge figures for either gauging station. Erosion rates of 187–238 t.km
−2
p.a. are established for the 782 km
2
drainage system.
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.
A new Carboniferous fenestrate bryozoan genus
Authors: Bancroft Adrian J.
Published: January 2010

Synopsis

A new fenestrate bryozoan
Polyfenestella
with the type species
Polyfenestella fenestelliformis
(Young, 1881) is described from the Carboniferous of the Midland Valley of Scotland. Colonies form reticulate expansions of branches connected by regularly spaced dissepiments. Branches bear two rows of autozooecia. In addition to autozooecia two types of heterozooecia occur. Type A-zooecia are common, and are irregularly arranged between autozooecia. Type B-zooecia are abundant, and occur on both the obverse and reverse surface of branches.
Polyfenestella
is distinguished from
Fenestella
on the basis of the occurrence of type A- and type B-zooecia.
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.
Age of the Corodale Gneisses, South Uist
Authors: Whitehouse Martin J.
Published: January 2010

Synopsis

Whole-rock Sm-Nd and Pb-Pb ages of 2770 ± 140 Ma and 2900 ± 100 Ma respectively are presented from a suite of samples from the Corodale Gneiss unit of eastern South Uist, Outer Hebrides. The initial ε
Nd
value of
c.
+ 2.4 and model μ
1
value of 7.9 are typical of late-Archaean mantle source regions in the Lewisian and are similar to values obtained from other Lewisian mafic-ultramafic complexes. These data confirm that the igneous protoliths to the Corodale Gneisses belong to the earliest crust-forming episode in the Lewisian, and are not correlated with younger mafic intrusive rocks in South Harris. Although the Corodale Gneiss unit has undergone extensive tectonic disruption during formation of the Outer Isles Thrust, there has been little post-Archaean disturbance of large-ion lithophile elements: U and Th have remained immobile in most samples, and there has been limited redistribution of Rb within the Corodale Gneiss unit itself.
A plesiosaur from the Linksfield erratic (Rhaetian, Upper Triassic) near Elgin, Morayshire
Authors: Taylor Michael A. , Cruickshank Arthur R. I.
Published: January 2010

Synopsis

An apparent series of eight plesiosaurian cervical vertebrae and an isolated tooth are described from the Rhaetian (or possibly Lower Jurassic) erratic block at Linksfield, Elgin, Morayshire. The vertebrae are comparable to Rhaetian and Hettangian material from SW England, especially the Rhaetian species
Plesiosaurus costatus
Owen, 1840 and
Plesiosaurus rugosus
Owen, 1840. The vertebrae comprise a rare occurrence of associated Rhaetian plesiosaurian skeletal material.
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.
Late Devensian and Holocene relative sea level and environmental changes from an isolation basin in southern Skye
Authors: Selby Katherine A. , Smith David E. , Dawson Alastair G. , Mighall Timothy M.
Published: January 2010

Synopsis

Detailed lithostratigraphical and biostratigraphical studies from an isolation basin at Inver Aulavaig on the Sleat Peninsula, Isle of Skye, Scotland, disclose changing environmental conditions during the Late Devensian and Holocene. In particular, they reveal three marine transgressions at the site since the Late Devensian, when the sea crossed the rock threshold at +5.10 m
od
. The radiocarbon dates obtained may incorporate hard water errors, but are considered broadly indicative of the ages of these events. The earliest event recorded at Inver Aulavaig, took place prior to
c
. 12600
14
C
bp
and probably occurred soon after deglaciation as relative sea levels rose while the area was isostatically depressed. The second, which occurred between 8850±170 and 5440+50
14
C
bp
, is correlated with the Main Postglacial Transgression. The third, which briefly took place between the statistically indistinguishable dates of 3160±40 and 3070±60
14
C
bp
is believed to correlate with a widespread transgression recorded at several sites around the periphery of the Scottish glacio-isostatic uplift centre. The results would also appear to indicate that relative sea level in this area during the Younger Dryas did not exceed +5.10 m
od
.
The use of magnetic separation techniques to detect basaltic microtephra in last glacial-interglacial transition (LGIT; 15–10 ka cal.
bp
) sediment sequences in Scotland
Authors: Mackie Elizabeth A. V. , Davies Siwan M. , Turney Chris S. M. , Dobbyn Kevin , Lowe J. John , Hill Peter G.
Published: January 2010

Synopsis

Basaltic tephra horizons dominate the Icelandic tephrochronological framework during the last glacial-interglacial transition (LGIT; 15–10 ka cal.
bp
), providing excellent potential for high precision correlation of palaeoclimate data-sets as recorded in ice, marine and terrestrial sequences of the North Atlantic region. Although significant advances have been made in identifying and extending the known provenance of rhyolitic tephras (in the form of microtephra horizons), the detection of basaltic layers has proved problematic. The bimodal Vedde Ash is an important chronological marker horizon that lies firmly within the GS-1/Younger Dryas chronozone (ca. 10.3 ka
14
C
bp
; 12.0 ka GRIP ice-core yrs) and provides an excellent opportunity to develop methodologies for extracting both rhyolitic and basaltic ash. The recent identification of the rhyolitic component across Europe using flotation techniques has significantly extended the known provenance of this eruption event. However, there is no routine methodology for the identification of basaltic microtephra horizons and the separation of this component of the Vedde Ash has therefore been limited to visible horizons in Iceland, western Norway and the Isle of Skye. Here, we use magnetic separation techniques to identify for the first time basaltic Vedde Ash as a microtephra horizon in minerogenic sequences from two sites in western Scotland.
The
Pristiograptus dubius
(Suess, 1851) species group and iterative evolution in the Mid- and Late Silurian
Authors: Rickards R. B. , Wright A. J.
Published: January 2010

Synopsis

Pristiograptus dubius
(Suess, 1851), one of the longest-known graptolites, is also one of the simplest and longest ranging (about 20 Ma). As well as giving rise to new genera, such as
Colonograptus
Přibyl (1943
c
) and
Saetograptus
Přibyl (1943
c
) amongst others, it also repeatedly gave rise to both broad and narrow short-lived pristiograptids, cases of iterative development. These closely resemble
P. d. dubius
and are often difficult to distinguish from it, especially in cases of indifferent preservation or tectonic deformation: a stratigraphy known on independent criteria is a great facilitator to identification! There is no difference in the overall range of broad versus narrow species, but the latter are more numerous. The parent species
P. d. dubius
survives them all and extends almost to the top of the Přídolí. The origin of the
P. dubius
lineages is probably through
P. initialis
Kirste (1919) and
P. pergratus
in the latest Llandovery, and
P. praedubius
(Bouček, 1931) in the earliest Wenlock.
Pristiograptus d. dubius
is a stem lineage in the sense of Urbanek (1998).
Alternatives in Paleocene exploration West of Shetland: a case study
Authors: Smallwood John R. , Prescott David , Kirk Wayne
Published: January 2010

Synopsis

This paper illustrates oil exploration in the West of Shetlands area from 1995 to 2001 by documenting the history of Block 205/9, awarded in the UK 16th Licensing Round in 1995. Good quality Paleocene sands had been encountered in the 1989 well 205/9-1 in the down-dip part of the block, and equivalent sands were absent on the adjacent Flett Ridge to the SE, setting up the possibility of a pinchout play. The first well testing the play, 205/8-1, was drilled on the overall pinchout on 2D seismic data, but 3D seismic data were acquired across the area to better delineate the depositional systems. The first well drilled on the 3D data to test the sand pinchout, 205/14-3, failed to encounter sands in communication with those in 205/9-1, so attention turned to alternative stratigraphic traps highlighted by seismic amplitude anomalies. Detailed evaluation of the seismic data revealed that the attractive seismic amplitude response of one potential prospect was actually an artefact associated with overlying basalt. Further analysis of the 3D seismic attributes identified a tongue of sand south of 205/9-1, and analysis of magnetic fabrics from core data in 205/9-1 revealed that sand was input to this area from the NE, contrary to previous models. Unfortunately the seismic attributes, supported by fluid inclusion data, suggested that the sand was water-wet. As a result of the evaluation work, the block was relinquished in 1999 without further drilling. While there is undoubtedly scope for stratigraphic traps in the area to prove hydrocarbon-bearing, experience on the 205/9 block and other studies led to a refocusing on dip-closed structures, and a resulting discovery, the first in the Faroes, consisted of 170 m of hydrocarbon-bearing sands in the T10 Paleocene interval.
An overview of groundwater in Scotland
Authors: MacDonald Alan M. , Robins Nick S. , Ball Derek F. , Ó Dochartaigh Brighid É.
Published: January 2010

Synopsis

Groundwater is an important, but undervalued, national resource in Scotland. Groundwater is present both in the bedrock, where much of the flow is through fractures, and in the superficial deposits, where intergranular flow dominates. The most productive bedrock aquifers are the Permian sandstones and breccia in SW Scotland and the Devonian sandstones in Fife, Strathmore and Morayshire. Alluvium and fluvio-glacial sands and gravels can also form important aquifers and provide some of Scotland’s most highly yielding boreholes. Groundwater is generally weakly mineralized with total dissolved solids in the range 100 to 500 mg l
−1
and is dominated by Ca and HCO
3
type waters.

There are in excess of 4000 boreholes in Scotland, and over 20 000 springs and wells used for private water supply. There are few available reliable data on the total volumes of groundwater abstracted; however, conservative estimates suggest that the total volume is approximately 330 megalitres per day for public water supply, industry, agriculture and private water supply. The volume of groundwater used in public water supply is growing annually; it is currently 7% of the daily 2400 megalitres per day supplied by Scottish Water. Scottish groundwater is under threat from agricultural activity, the mining legacy, septic tanks, localized high abstraction, and general land development. The implementation of the Water Framework Directive, and associated legislation, is an excellent opportunity to sustainably manage and develop groundwater in Scotland.
A groundwater recharge methodology for Water Framework Directive initial characterization in Scotland
Authors: Church Richard
Published: January 2010

Synopsis

Estimation of recharge to groundwater is an important component in the characterization of groundwater bodies for the Water Framework Directive (WFD). The time scale allowed for the WFD initial characterization required a pragmatic methodology for efficient assessment of recharge to each delineated groundwater body. An assessment methodology was developed through a project funded by the Scotland and Northern Ireland Forum for Environmental Research, although it has application throughout the UK. Few recharge calculations have previously been attempted in Scotland. The environmental influences on recharge processes differ from much of the rest of the UK and the ability of the groundwater body to accept recharge is a key criteria.

The method proposed is based on a water budget approach which estimates direct and indirect recharge flow components. It includes estimation of effective rainfall, actual evapotranspiration, surface run-off and interflow in addition to the potential impacts of snow-melt, bypass flows, urban recharge and surface water leakage where appropriate. This is calculated on a daily or monthly time step with the use of a spreadsheet software tool. The degree of uncertainty in the recharge estimation increases with the scarcity of data available to the groundwater body. Many recharge estimations in Scotland will rely on national-scale mapping of climatic, land use, soil and aquifer properties. It is important that the confidence in the estimation is balanced against the perceived risk of stress to the groundwater body. Validation of the recharge calculations is ongoing and the assessment of bypass flow and interflow has been determined as critical to the accuracy of the calculation.
Numerical testing of conceptual models of groundwater flow: a case study using the Dumfries Basin aquifer
Authors: Jackson C. R. , Hughes A. G. , Ó Dochartaigh B. É. , Robins N. S. , Peach D. W.
Published: January 2010

Synopsis

The current understanding of the groundwater flow regime in the Dumfries Basin aquifer has been developed over a number of years and encapsulated in a conceptual model. A numerical modelling study has been undertaken to test the confidence in this understanding. This study has included three activities: recharge estimation, water balance calculations and steady-state groundwater flow modelling. It has been confirmed that the highest recharge is found in the NW of the basin and that the peat and marine clay deposits limit direct recharge in the east and south. The water balance is dominated by surface water flow, in particular the River Nith brings over 3200 Ml day
−1
onto the basin. Conceptualized flow directions were confirmed by the steady-state modelling. The understanding and model validity are severely constrained by a lack of flow data in the lower River Nith and scarcity of water level and aquifer property information. These knowledge gaps could be filled by flow gauging just above the tidal limit of the river and additional drilling and testing.