bluuebunny/crossref_metadata_2025 huggingface dataset:
Dislocation surfaces in the Moine Thrust Zone, Ullapool
Authors: Cheeney Robert F.
Published: January 2010

Synopsis

Coward (1988)
inferred extension both parallel and perpendicular to the Moine Thrust based on his description of the section between Loch Broom and Strath Kanaird. A multitude of dislocations pervades these rocks, especially those between the Moine Thrust and the Foreland, the understanding of which requires commensurate levels of good exposure. Additional data from such areas permit interpretations supplementary to those of the earlier work. In particular, a well-exposed, supposedly exhumed dislocation surface is described; a scoop-like surface developed in Cambrian strata, concave up, traced over a distance of about 80 m. Similar forms may be detected in the upper Ullapool River valley, with intersections that suggest sequential emplacement, although the precise history remains undetermined. The present structural thickness of the zone between Foreland and Moine Thrust decreases markedly towards WNW. The kinematics remain conjectural, with some circumstantial evidence of high pore-fluid pressures that may have promoted gravitational instabilities in uplifted Lewisian/Torridonian masses.
Age of the Garantiana Clay (Middle Jurassic) in the Hebrides Basin
Authors: Morton Nicol , Dietl Gerd
Published: January 2010

Synopsis

Uncrushed ammonites belonging to the possible dimorph pair
Garantiana
(G.) aff.
garantiana
(d'Orbigny) (M) and G. (
Pseudogarantiana
)
dichotoma
Bentz (m) were found in nodules from the Garantiana Clay Member near Brae, Isle of Raasay. The age of this can now be established as
dichotoma
Subzone,
garantiana
Zone, Upper Bajocian, giving more precise dating of the subsequent change to non-marine conditions in the Hebrides Basin.
A tonstein from the Lower Limestone Group of Arran
Authors: Huff W. D. , Spears D. A.
Published: January 2010

Synopsis

A 4 cm tonstein, in an oxidised coal seam above the Corrie Limestone on the east coast of Arran, formed by the
in situ
alteration of air-fall volcanic ash. The tonstein consists predominantly of well-crystallised kaolinite as subparallel grains of altered biotite and more equidimensional vermiform rouleaux formed from pre-existing feldspar or pumice fragments. Accessory minerals include pyrite, apatite, quartz, anatase and illite.

SEM photos of some kaolinite grains exhibit cornflake texture described by
Keller (1978)
as characteristic of smectite in bentonites. Chemical analyses by XRF suggests a secondary quartz content between 10–14% which is supported by powder XRD data. Trace element plots show the precursor ash was basic in composition. Fe
2
O
3
content is near 10%, which is considerably higher than most other tonsteins and probably indicates extensive leaching and oxidation during either Permian or Tertiary time. Pyroclastics of the same age occur on the mainland near the top of the Hosie and Hurlet Limestones and may be the stratigraphic equivalent of the Arran tonstein.
Sedimentological evidence for a major subsurface fracture system linking the eastern Campsie and the eastern Ochil faults
Authors: Read W. A.
Published: January 2010

Synopsis

Evidence for intra-Carboniferous and end-Carboniferous right-lateral strike slip within the Midland Valley is concentrated along lineaments which reflect major subsurface fracture systems. One such lineament runs ENE below the Kincardine Basin and joins the eastern Campsie Fault to the eastern Ochil Fault. This moved right-laterally during the deposition of the Passage Group, as proved by contemporaneous movements of its associated oblique folds.

The hinge line between the Tulliallan Trough ‘low’ and the Bogside Saddle ‘high’ follows this lineament. The ‘low’ controlled the locus of the major Saline Channel Belt throughout most of the Namurian, whereas unusually thick peats commonly accumulated over the ‘high’. Reversals of apparent downthrow along this hinge reflected movements, probably right-lateral strike slip, along the underlying lineament. Low-angle detachments may explain the absence of any major ENE–WSW trending surface fracture above the lineament in the Kincardine Basin.

The lineament, which probably extends WSW below the eastern part of the Milngavie–Kilsyth Fault to underlie the Paisley Ruck, may have been initiated as a Riedel Shear by right-lateral strike-slip along the Highland Boundary Fault, or it may reflect a reactivated Late–Caledonian left-lateral strike-slip fault system.
The petroleum potential of the Old Red Sandstone of northern Scotland
Authors: Trewin N. H.
Published: January 2010

Synopsis

The Devonian of northern Scotland and the Moray Firth contains lacustrine oil source rocks in both the Lower and Middle divisions. In onshore areas the majority of the source rocks lie in the oil window with the least mature rocks situated both at the basin margin and at the top of the succession in the main basin area which contains thick Middle ORS. Hydrocarbons generated and reservoired in pre-Permian times were probably lost during faulting and erosion episodes at the end of the early Devonian, the end of the mid-Devonian and in Carboniferous-Permian times.

Devonian rocks preserved beneath Permian and Mesozoic basin fills in excess of 2 km in the Inner Moray Firth would have generated hydrocarbons from late Jurassic times onwards. These hydrocarbons could be preserved within fault blocks or have migrated to reservoirs in the Mesozoic as has been postulated in the case of the Beatrice Oilfield.

The most prospective exploration areas for Devonian-sourced oil are considered to be in the Great Glen and Wick Sub-Basins and the Smith Bank Graben.
The early Kimmeridgian ammonite succession at Staffin, Isle of Skye
Authors: Wright John K.
Published: January 2010

Synopsis

Detailed mapping of the Staffin Shales in the vicinity of the Oxfordian/Kimmeridgian boundary has revealed a succession of ammonite faunas, one of which was only known previously from Greenland. Recognition of distinctive marker bands has enabled correlation of scattered outcrops along 3 km of coastline and has revealed details of the manner of operation of the Quirang landslip.
Barrier island to tidal shelf transition in the early Cambrian Eriboll Sandstone
Authors: McKie Thomas
Published: January 2010

Synopsis

The Cambrian Eriboll Sandstone, 150–225 m of quartz arenites deposited on the western margin of the Iapetus Ocean, consists of a Lower Member (75–125 m thick) overlain by the Pipe Rock Member (75–100 m thick). The basal 10 m consists of tabular cross-bedded sands deposited within channels of a mesotidal barrier island system. These sands are truncated by an extensive ravinement surface overlain by thin cross-bedded and parallel-bedded shoreface sands with bimodal palaeocurrents. The ravinement surface reflects erosional retreat of the barrier foreshore and upper shoreface during transgression. Lower shoreface deposits were dominated by storm and tidal processes. Palaeocurrents in these were enhanced by superposition of northwards flowing geostrophic storm currents. Shoreface sands pass upwards into tidal shelf sands deposited as dunes and sandwaves. Sandwave cosets thicken upwards in the Lower Member indicating increased tidal current velocities. This may reflect resonant amplification of tides as the shelf became wider during sea level rise.

As the transgression proceeded the bioturbated Pipe Rock was deposited. Proximal deposition was by large compound sandwaves, similar to those below, and grading offshore into small, simple dunes and sandwaves. Distal fades were storm dominated. Both were populated by suspension feeding animals which produced abundant
Skolithos
burrows.
Late Devensian glaciation of southern Caithness
Authors: Hall A. M. , Whittington G.
Published: January 2010

Synopsis

A formal stratigraphy is proposed for the Quaternary deposits of south-east Caithness. A shelly till from the Moray Firth, the Forse Till, overlies an early till from inland, the Balantrath Till, which demonstrates an expansion of inland ice on to the edge of the plain of Caithness. Along its south-eastern margin the Forse Till is found interbedded with the Balantrath Till in the Dunbeath Water valley and a second inland till, the Ladies’ Tent Till, in the Langwell Water valley. The stratigraphy indicates that Moray Firth ice was contiguous with inland ice at this stage and evidence from striations shows that inland ice was diverted to run northwards parallel to the margin of the inland ice. After retreat of Moray Firth ice there was a minor advance of inland ice in the Berriedale area and formation of hummocky moraine. There is no evidence of any subaerial exposure within till sequences and the tills are therefore related to a single, complex phase of glaciation. The Forse Till and the Ladies’ Tent Till are overlain by peats of Windermere Interstadial age and by gelifluctates of Loch Lomond Stadial age. A variety of relative age criteria indicate that almost all the Quaternary deposits of south-east Caithness are of Late Devensian age.
Pressures and temperatures of Dalradian metamorphism and the andalusite–kyanite transformation in the northeast Grampians
Authors: Beddoe-Stephens B.
Published: January 2010

Synopsis

Pressures and temperatures have been derived from Dalradian pelitic schists within the area from Tomintoul to the Banffshire coast, predominantly in terrain west of the Portsoy–Duchray Hill lineament and straddling the andalusite–kyanite inversion isograd. These indicate that pressures up to 8–9 kb occur at the base of the Dalradian sequence compared to 4–5 kb immediately west and east of the lineament. There is also a sharp thermal break across the lineament. Replacement of andalusitc by kyanite at Portsoy and further south to the west of the lineament implies that rocks in this area underwent a significant pressure increase. P–T path calculation using garnet zoning confirms this and indicates the increase to have been about 2 kb.

Following
Baker (1987)
it is postulated that the Portsoy lineament represents a thrust plane and that low-P, high-T Dalradian rocks of the Buchan terrain were thrust westwards, deformation that can be related to the local D2 episode. This event postdated emplacement of the Newer Basic masses. Later D3 movements resulted in rapid differential exhumation of the Dalradian which was partly taken up by further shear movement on the Portsoy lineament steepening it to its present attitude.
Former ice movement in Assynt, Sutherland, as shown by the distribution of glacial erratics
Authors: Lawson T. J.
Published: January 2010

Synopsis

The distribution of glacial erratics shows that at some time in the past the Assynt area has been glaciated by an ice sheet of considerable thickness which, at the glacial maximum, probably covered all but the highest mountains. Whether this was the Late Devensian ice sheet or some earlier glacial phase cannot be determined from the evidence of glacial erratics alone. A model for the development of an ice sheet in this part of Scotland is proposed, whereby initial ice development occurred predominantly on the eastern side of the mountains, with glacial build-up continuing until the ice was thick enough to flow westwards as well as eastwards. The ice divide thus established always lay to the east of the Assynt mountains. The dispersal of erratics appears to have been limited in the ice-shed zone.
S.E.M. study of clastic fabrics preserved in calcareous concretions from the late-Devensian Errol Beds, Tayside
Authors: Duck Robert W.
Published: January 2010

Synopsis

S.E.M. studies of the clastic components of calcareous concretions from the late-Devensian, glaciomarine Errol Beds near the type site, east-central Scotland, reveal fabrics indicative of deposition from originally flocculated suspensions. Previously undescribed spherical cavities 30–350 μm in diameter, characteristically fringed by aligned platy particles, are thought to have been former gas bubbles around which the grains adhered by surface tension. It is suggested that the gas was ammonia, believed to have been derived from the decay of proteinaceous organic matter which promoted localised CaCO
3
precipitation through a rise in pH. The delicate, porous fabrics preserved via cementation indicate that the concretions are of early diagenetic origin and formed rapidly, close to the sediment–water interface. In contrast, the fabrics shown by the host clays are consistent with consolidation of originally flocculated materials.
A new Lower Ordovician conodont faunule from the Northern Belt of the Southern Uplands
Authors: Armstrong H. A. , Clarkson E. N. K. , Owen A. W.
Published: January 2010

Synopsis

A deep water
Periodon—Prioniodus—Protopanderodus
assemblage has been isolated from red cherts and mudstones in the Hawkwood Burn, a tributary of the Wandel Burn. Constraints provided by associated graptolites and the absence of
Pygodus
and Arenig taxa known to occur in the Southern Uplands suggest this part of the sequence is Llanvirn in age.
Tidal sandbank evolution in the Lower Cambrian Salterella Grit
Authors: McKie Thomas
Published: January 2010

Synopsis

The Lower Cambrian Salterella Grit is a 0–15 m thick sequence of quartzarenites, siltstones and mudstones and represents an inner shelf tidal sandbank and sandwave complex. The bank facies consists of a coarsening-upward unit up to 15m thick, containing metre-scale cross-bedded sets enclosed by bounding surfaces that dip gently in a direction perpendicular to the palaeocurrent direction. Bank apron sandstones are thinner bedded with a greater proportion of mud-stones, an increased faunal diversity and bimodal palaeocurrents. The Salterella Grit banks were initiated following an abrupt regressive phase, the sediment being derived from local erosion of the underlying Fucoid Beds. During the subsequent transgression the shelf deepened, mean tidal velocities were reduced and the banks became moribund. Moribund bank facies are characterised by thin, highly burrowed sandstones which were deposited on the flanks of banks and in troughs between the banks. Further reduction in tidal currents resulted in the deposition of a thin sandstone sequence of storm origin in the troughs between banks. Nearshore facies are represented by smaller cosets which also show a vertical increase in bioturbation and decrease in thickness.
An early-Proterozoic age for the Ness anorthosite, Lewis, Outer Hebrides
Authors: Whitehouse Martin J.
Published: January 2010

Synopsis

Whole-rock Nd-isotopic data from the Ness anorthosite are consistent with an early-Proterozoic age for this body rather than the late-Archaean (Scourian) age inferred from geological relationships. Sm–Nd isotope systematics are interpreted as the result of interaction of an early-Proterozoic (
c.
2200 Ma) mantle-derived anorthositic magma with late-Archaean Lewisian gneisses. An early-Proterozoic protolith age suggests a possible correlation with the South Harris anorthosite. A Pb/Pb isochron age of 1860 ± 240 Ma is thought to represent the same early-Laxfordian high-grade mctamorphism that occurred in the South Harris complex.

The similarity of Nd-isotope systematics, probable metamorphic history, and tectonic setting are considered to be strong evidence that the Ness and South Harris anorthosite bodies are coeval. However, a single early-Proterozoic anorthosite protolith body would need to be regionally extensive and is considered unlikely.
Authigenic sphene cement in Permian sandstones from Arran
Authors: van Panhuys-Sigler Michéle , Trewin Nigel H.
Published: January 2010

Synopsis

Permian sandstones from the Cock of Arran area contain small amounts of sphene cement. The sphene occurs as a minor phase (up to 2%) in small patches cementing several grains, and as individual crystals with well developed crystal faces grown into pore space from quartz, feldspar or lithic grain surfaces. The sphene postdates the growth of red grain pellicles and chlorite rosettes and probably formed at a time of calcite dissolution and creation of secondary porosity. Sphene is apparently absent from Permian sandstones at Corrie and Brodick. It is postulated that the sphene was deposited from convective fluids associated with the intrusion of the Arran Granite in Tertiary times. Ti was probably derived from the alteration of Ti-bearing oxides and volcanic rock fragments in the sandstones.
Palaemysis dunlopi
Peach 1908 (Eocarida, Crustacea) from the Namurian (Carboniferous) of the western Midland Valley
Authors: Clark N. D. L
Published: January 2010

Synopsis

Palaemysis
is one of five eumalacostracan genera obtained from Namurian shales in the western Midland Valley of Scotland. On the basis of the preserved morphology alone, it was concluded that
Palaemysis
should be retained within the Eocarida rather than being assigned to any extant group.

Palaemysis
differs substantially from
Anthracophausia
despite having been previously considered as synonymous. These differences include the presence of a large rostrum in
Anthracophausia,
the shape of the telson and uropods, the shape of the abdominal pleura, and the presence of a large pair of anterior spinose appendages (mandibular palps) in
Palaemysis.
The three species of
Palaemysis, P. dunlopi, P. couttsi,
and
P. tenuis,
were first erected on the basis of poorly preserved tail fans. These species could not be adequately, morphometrically or morphologically, differentiated and only one species of
Palaemysis
is therefore recognised. The species of
Palaemysis
is taken to be that of the original type species,
P. dunlopi.
New pollen-stratigraphic evidence for the deglaciation and lake drainage chronology of the Glen Roy-Glen Spean area
Authors: Lowe J. John , Cairns Peter
Published: January 2010

Synopsis

Pollen-stratigraphic evidence is presented from a number of sites in Glen Roy and lower Glen Treig. The new data do not support the chronology of the Glen Roy-Loch Laggan proglacial lake drainage proposed by Macpherson (1978). The evidence also has a bearing on the controversy over the age of outwash fan deposits in upper Glen Roy, and this problem is re-examined here. Since no Late Devensian Lateglacial deposits are found anywhere in the region, whereas early Flandrian (Holocene) successions are found in several basins, the evidence as a whole is interpreted as indicating that the outwash deposits at the Roy–Turret confluence are of Loch Lomond Stadial age.
Xenoliths in the lamprophyre dykes of Lomondside: constraints on the nature of the crust beneath the southern Dalradian
Authors: Dempster T. J. , Bluck B. J.
Published: January 2010

Synopsis

Xenoliths within a late-Caledonian lamprophyre dyke intruded into Dalradian metasediments reveal the presence at depth of Dalradian rocks of relatively high regional metamorphic grade and probable Highland Border Complex rocks. The xenolith suite is largely composed of fragments of cognate cumulate rocks together with metamorphosed country rocks both associated with a deep magma chamber. The latter formed close to the Highland Boundary Fault, which dips to the north beneath a thickened Dalradian pile. Pyrope-rich garnets within the xcnocryst assemblage may indicate that the lamprophyre magma originated in high pressure rocks within the mantle.
Geophysical evidence for a concealed Caledonian intrusive body at Sandhead, Wigtownshire
Authors: Kimbell G. S. , Stone P.
Published: January 2010

Synopsis

A marked magnetic anomaly at Sandhead, 11 km SSE o f Stranraer on the Rhins of Galloway, has been modelled in terms of an intrusive body which rises to within 50 m of the ground surface. Two culminations are apparent but both remain concealed beneath a cover of hornfelsed Ordovician and Silurian grey-wackes. The intrusion seems most likely to be a late Caledonian diorite. The controlling influence on its location and shape was possibly a late phase of dextral shear on the Cairngarroch (Orlock Bridge) Fault.
Geochemistry, weathering and diagenesis of the Diabaig Formation (Torridon Group) in NW Scotland
Authors: Rodd J. A. , Stewart A. D.
Published: January 2010

Synopsis

The late Proterozoic Diabaig Formation consists of alluvial red breccias and sandstones, and lacustrine grey shales, which accumulated in the lower parts of palaeovalleys eroded in gneiss. The sediments are significantly depleted in Ca and Na with respect to the local gneisses which provided 80% of the sediment. Geochemical mass balance calculations, taken together with the mineralogy, show that these losses occurred mainly during breakdown of plagioclase and amphibole during sediment transport and reworking. Mobilisation of Ca and Na during diagenesis was quantitatively insignificant, despite clear evidence for albitization of detrital plagioclasc. There is no evidence of primary carbonates or evaporites in the shales. The Ca and Na removed from the sediments was lost to a hydraulically open, regionally extensive lake.
The differentiated dolerite boss, Cnoc Rhaonastil, Islay: a natural experiment in the low pressure differentiation of an alkali olivine-basalt magma
Authors: Hole M. J. , Morrison M. A.
Published: January 2010

Synopsis

The Cnoc Rhaonastil dolerite boss is a differentiated minor intrusion elongated parallel to one of the four component sub-swarms of the Islay–Jura dyke swarm. Differentiation is from alkali olivine-dolerite to teschenite with minor nepheline-syenite locally. On the basis of field, petrographic, mineralogical and geochemical data, three distinct varieties of dolerite are identified, the most primitive of which represents the chilled margin of the intrusion, with a compositional continuum being evident for the boss as a whole. REE profiles and chondrite normalised ‘spidergrams’ exhibit a marked parallelism for the dolerites and teschenite, with ratios of incompatible trace elements being almost constant throughout differentiation. Both petrographic and geochemical data demonstrate that differentiation was controlled by early crystallisation of olivine and plagioclase, with clinopyroxene having little influence on the chemical evolution of the boss. The syenites represent residual liquids which were segregated from the partially crystallised dolerites and teschenite by dynamic processes. Differentiation occurred
in situ
at low pressures, with P

H
2
O

increasing with increasing degree of differentiation. This boss is a type example of the low pressure crystallisation of an alkali olivine-basalt magma.
Porphyroblast–fabric relationships: an example from the Appin Group in the Glen Roy area
Authors: Phillips E. R. , Key R. M.
Published: January 2010

Synopsis

The Neoproterozoic Grampian and Appin groups exposed in the Glen Roy area were deformed during an initial progressive tectono–thermal event of the Grampian orogeny. Prograde regional metamorphism to amphibolite facies accompanied deformation with the thermal peak coinciding with the second phase of folding (F2) and the imposition of an S2 crenulation to transposition fabric. In the pelitic to semipelitic schists of the Lochaber Subgroup (Appin Group), metamorphism resulted in the development of the assemblage: quartz + muscovite + biotite ± garnet, plagioclase (An 13 to 22%), staurolite and opaques. The complexity of porphyroblast–fabric relationships recorded from the schists varies systematically across the area and can be directly related to the intensity of S2. Six progressive stages of S2 crenulation cleavage development are recognized, preserved within multitextured, syn-kinematic garnet porphyroblasts. These stages show a progression from a planar S1 fabric to differentiated S2 crenulation cleavage, through to the development of a differentiated S2 transposition fabric. Porphyroblast–fabric relationships are further complicated by the localized reactivation of S1 in response to movement along the Grampian–Appin lithostratigraphic boundary during F2 folding. Biotite porphyroblasts developed early during the imposition of S2 and were subsequently deformed during D2 to form lenticular mica-fish. Staurolite (rare) nucleation and growth, representing peak metamorphism recorded by these schists, post–dated S2 development.
A new crinoid from the Ashgill Starfish Bed, Threave Glen
Authors: Donovan Stephen K.
Published: January 2010

Synopsis

A cincinnaticrinid disparid crinoid,
Serendipocrinus lamonti
gen et sp. nov., is described from the Rawtheyan (Ashgill, Ordovician) of the Threave Glen Starfish Bed, Craighead Inlier, SW Scotland. This species has a robust, skyphosiform dorsal cup with low basals; uniserial, apinnulate arm s which branch isotomously at 1Br
2
and 2Br
3
; and an anal series supported by the C superradial and D radial. This is the first true cincinnaticrinid to be described from the British Ordovician.
Evidence of tidal influences in Arnsbergian rhythmites in the Kincardine Basin
Authors: Read W. A.
Published: January 2010

Synopsis

Distinctive, vertically accreted rhythmitcs, in which evenly stratified bands of fine-grained silty sandstone alternate with much thinner bands of silty mudstone, overlie the thick marine mudstones above the Orchard and Calmy limestones in the Upper Limestone Group of the Kincardine Basin, east of Stirling. Each sandy band, together with the overlying mudstone band, is thought to represent a tidal bundle, with the sandstones being deposited during the more rapid stages of tidal flow and the mudstones during slack water.

Successive sandstone bands are alternately thick and thin, reflecting dominant and subordinate tides, so that the mudstone bands are grouped into pairs. The rhythmites are similar to some Holocene vertically accreted tidal deposits, but more closely resemble Pennsylvanian tidal rhythmites in the Illinois Basin in which regular neap—spring—neap tidal cycles have been identified.

Marine flooding was unusually widespread and deep during the major transgressions associated with the two limestones. This flooding may have produced wide, funnel-shaped inlets which amplified the tidal range, as well as ponding back rivers and consequently markedly reducing siliciclastic input into the basin.

Tidal processes probably influenced British Carboniferous sedimentation more commonly than has hitherto been supposed.
Geochemistry and provenance of red sandstones in the Upper Proterozoic Torridon Group in Scotland
Authors: Stewart A. D. , Donnellan N. C. B.
Published: January 2010

Synopsis

The Torridon Group consists mainly of alluvial red arkoses (Applecross and Aultbea Formations), over 4 k m thick. The arkoses have average whole rock ratios K/Rb ≈ 320 and La/Th ≈ 3, suggesting source areas on upper continental crust. Palacocurrents and geochemistry point to the Outer Hebrides as the provenance. Scourian amphibolite facies gneisses and Laxfordian granites, like those in the Outer Hebrides today, could have provided most of the arkoses. A small contribution, represented by pebbles, stems from supracrustal metasediments and volcanics not now exposed in Scotland.

The Rb and Sr contents of the feldspars, modelled from double ratio plots of whole rock analytical data, show major changes in source terrain at the Applecross—Aultbea boundary, and elsewhere.

The oldest Applecross sediment in Coigach was little weathered prior to deposition, but plagioclase becomes less abundant upward through the formation and is almost absent 800 m above the base. From this, the initial source area relief is inferred to have been 2—3 km, subsequently decreasing by an order of magnitude. On average all the amphibole and about three-quarters of the plagioclase was removed from the source rocks of the Applecross and Aultbea Formations by weathering before sedimentation.
Late Proterozoic and Late Palaeozoic movement on the Coigach fault in NW Scotland
Authors: Stewart A. D.
Published: January 2010

Synopsis

Movement on the NNE-trending Coigach fault in NW Scotland can be dated by reference to the late Proterozoic Stoer and Torridon Groups which it cuts. It behaved as a normal fault in late Stoer Group time, with downthrow to the east. The fault was reactivated after the Cambrian as a listric fault with a downthrow to the west, displacing Torridon Group sediments about 5 km. Roll-over near the fault suggests that it soles out at around 8 km below present sea level. Most of the post-Cambrian movement was probably Devonian or Carboniferous. Mesozoic and later movement was negligible. Other NNE-trending faults on the mainland resemble the Coigach fault in showing large pre-Triassic displacements of the Torridon Group.
Evaporites in the Middle Devonian of the Orcadian basin near Berriedale, Caithness
Authors: Donovan R. N.
Published: January 2010

Synopsis

A Middle Devonian Old Red Sandstone outlier at Berriedale, Caithness, is interpreted as a low energy, fluvio-lacustrine sequence which was deposited in an embayment on the southwestern margin of the Orcadian basin. The lacustrin e facies contains rare pseudomorphs and crystal casts, probably after gypsum. Replacement minerals are mostly ferroan and non-ferroan calcite but also include chert varieties, pyrite, haematite, siderite, and barite. It is suggested that drusy carbonate pseudomorphous textures are crystal-cast-filling cements, whereas anhedral sparite mosaics record pseudomorph replacement. The complexity of the salt diagenesis is a reflection of an interplay between lake, surface, and ground waters.
New K-Ar ages, and a provisional chronology, for the offshore part of the British Tertiary Igneous Province
Authors: Hitchen K. , Ritchie J. D.
Published: January 2010

Synopsis

New K-Ar whole-rock ages are presented from 13 offshore locations to the north and west of Scotland. Ten of these locations have yielded ages which are considered to be geologically significant. Together with previously published ages, these suggest that the earliest sills of the Faeroe-Shetland Intrusive Complex were intruded at
c.
80 Ma (Campanian), although the bulk of the complex was probably emplaced at 55–53 Ma (early Eocene). Lavas on the Hebrides Shelf exhibit a range of ages from
c.
63–46 Ma (Danian-Lutetian). New K-Ar ages from Rosemary Bank are inconclusive but, combined with calcareous nannofossil analysis and the known magnetic polarity of the bank, suggest that it may have formed during the Late Cretaceous (70–68 Ma or earlier). The new data are incorporated into the chronology of all the major onshore and offshore components of the British Tertiary Igneous Province. Sources for the offshore lavas include the Faeroe Islands, central igneous complexes and large fissures such as those beneath the Wyville–Thomson Ridge and the Hebridean Escarpment.
Regional geochemical variation across the Iapetus Suture zone: tectonic implications
Authors: Stone P. , Green P. M. , Lintern B. C. , Simpson P. R. , Plant J. A.
Published: January 2010

Synopsis

Regional geochemical data from the Southern Uplands of Scotland and the Windermere Group of the English Lake District are assessed in terms of the underlying greywacke-dominated lithostratigraphical units. Stratigraphical (time-related) trends apparent in a number of elements continue from the Southern Uplands, across the Iapetus Suture, into the Windermere Group of the Lake District. The principal geochemical break occurs within the central Southern Uplands coincident with a major strike-parallel fault, the Moffat Valley Lineament. To the north of this structure a late Ordovician to early Silurian back-arc basin sequence has elevated Pb and As levels and feldspar-related element (Rb, K, Sr) abundances compatible with derivation of the greywackes from a granodioritic provenance. The mineralization potential of this sequence is stressed. To the south of the Moffat Valley Lineament a mid to late Silurian foreland basin sequence spans the Iapetus Suture with relatively lower Pb and As levels and feldspar element abundances suggestive of a moderately-evolved provenance. Development of such a foreland basin requires the effective closure of the Iapetus Ocean by the early Wenlock.
Geochemical variations within metavolcanic rocks of the Dalradian Farragon Beds and adjacent formations
Authors: Goodman S. , Winchester J. A.
Published: January 2010

Synopsis

A detailed petrological and geochemical study of metavolcanic schists of the Dalradian Argyll Group of the southern Highlands of Scotland reveals the activity of five main centres of volcanicity. Volcanic activity started with the localized eruption of low HFSE tholeiites comprising the Laoigh Metabasites during the deposition of the Ben Lawers Schist protolith in the Daldhu–Fearnate area. Subsequent deposition of the Farragon Beds was characterized by simultaneous eruption from three centres: low HFSE tholeiitic lavas and tuffs were produced in the Ben Vrackie area and in the Farragon area to the SW, while more fractionated high HFSE tholeiites were erupted in the intervening Pitcastle–Derculich area. A final volcanic episode occurred in the NE of the area, where transitional to alkaline basalts were produced during deposition of the Queen’s Hill Gneiss protolith. The composition of these metabasaltic’ rocks is consistent with volcanism in an extensional tectonic regime. The low HFSE contents of some magmas may result from their contamination during a residence time in the lower crust, while the later phase of more alkaline magmatism is consistent with current models of volcanism associated with extensional regimes.
New evidence that the high temperature hornblende-schists below the Shetland ophiolite include basic igneous rocks intruded during obduction of the ‘cold’ ophiolite
Authors: Flinn Derek
Published: January 2010

Synopsis

The hornblende-schists associated with the imbricate zones beneath the ophiolite nappes in Shetland include some that were emplaced as igneous intrusions into the base of the serpentinized ultrabasic upper nappe and into the thrust beneath it. These intrusive hornblendic rocks have chilled margins of nearly pure chlorite against the serpentinite, but internally they are composed of such high temperature minerals as brown hornblende, garnet and clinopyroxene. It is concluded that the high-temperature hornblende-schists beneath the ophiolite nappes are not part of a dynamothermal aureole as usually concluded, but the product of a high temperature basic magma derived by adiabatic melting deep in the mantle, which was intruded up the obduction thrust during obduction. This new evidence supports the conclusion drawn in an earlier paper that the ophiolite nappes were already serpentinized and relatively cool when obducted.
Pre-Flandrian slope deformation in the Scottish Highlands: examples from Glen Roy and Glen Gloy
Authors: Peacock J. D. , May F.
Published: January 2010

Synopsis

Slope deformation at localities in Glen Roy and Glen Gloy became essentially inactive prior to the formation of glacial lake shorelines (Parallel Roads) that are related to the maximum of Loch Lomond Readvance glaciers (10 500–10 000 BP). As such it is distinct from, and predates, differential uplift that has been linked with catastrophic lake drainage, landslip and possible seismic activity. The deformation is tentatively ascribed, first, to stress relief during glacial unloading and, second, to high cleft water pressures associated with the retreat of the main Late Devensian (Dimlington Stadial) ice across the area shortly after 13 000 BP and with permafrost, particularly during the Loch Lomond Stadial (11 000–10 000 BP). Such deformed, but almost featureless slopes may be present elsewhere where topography and structure are favourable: their preservation in Glen Gloy suggests that the upper part of this valley was not glaciated during the Loch Lomond Stadial.
A re-evaluation of ‘metasedimentary xenoliths’ in the West Highland Granitic Gneiss of Inverness-shire
Authors: Highton Andrew J.
Published: January 2010

Synopsis

Unusual syn-kinematic amphibole-bearing ‘metasedimentary’ lithologies within the outcrop of the Neoproterozoic Moine of the northern Highlands of Scotland have previously been interpreted as evidence of metasomatism apparently contemporaneous with alkaline igneous activity at the onset of the Ordovician tectonothermal event in this part of the Caledonian nappe belt. Several of these localities coincide with apparent metasedimentary enclaves within components of the Neoproterozoic West Highland Granitic Gneiss. These ‘enclaves’ are reinterpreted as xenolith-rich intrusions of quartzose amphibolite which are compositionally unique in terms of known meta-igneous rocks in the Moine, with unusually low Al
2
O
3
and elevated trace element contents. Mineral parageneses comprise essentially quartz, hastingsitic amphibole and biotite, with feldspar, sphene, allanite, zircon, apatite and monazite. Xenolith populations include both granitic gneiss and metasedimentary rocks. At the level of emplacement evidence of hybridization is lacking, with compositions appearing to reflect partial unmixing. Emplacement of these unusual magmas appears structurally to be broadly contemporaneous with the Ordovician (D3) tectonothermal event in the Sgurr Beag Nappe. These intrusions are considered to provide evidence of minor intrusive activity coincident with the pre- to syn-D3 alkaline magmatic event represented by the deformed pluton of the Glen Dessary Syenite.
Revision of the late Dinantian sequence in Edinburgh and West Lothian
Authors: Chisholm J. I. , Brand P. J.
Published: January 2010

Synopsis

An appraisal of exposed sections, mainly in the Water of Leith, and of the faunas collected from them, suggests a reinterpretation of the link between the well-known sequence in the West Lothian oil-shale field and the more fragmentary sections in Edinburgh. The Humbie Shell Bed of West Lothian and the Redhall Marine Band of Edinburgh were formerly supposed to lie respectively above and below the Hailes Sandstone, but are now thought to be the same bed, and to underlie the Hailes Sandstone. The evidence now available suggests that this marine band is the lowest of the Macgregor Marine Bands in the area. Four more marine bands in the underlying sequence in the Water of Leith cannot at present be recognized elsewhere.

The lithostratigraphical units Wardie Shales and Queensferry Beds, as formerly defined, were separated by the Hailes Sandstone, but the revised correlation implies that the sandstone lies within, not below, the Queensferry Beds. These units can no longer be used in their original sense, therefore, and a new stratigraphical nomenclature is proposed. The top of the Wardie Shales, formerly drawn at the base of the Hailes Sandstone, is now taken at the Redhall Marine Band. The strata above the marine band already belong to the Calders Member of the West Lothian Oil-Shale Formation, so the term Queensferry Beds becomes redundant, and the Hailes Sandstone becomes a unit within the Calders Member.
Lithostratigraphy of the Dinantian Inverclyde and Strathclyde Groups, Cockburnspath Outlier, East Lothian – North Berwickshire
Authors: Andrews Julian E. , Nabi Ghulam
Published: January 2010

Synopsis

A revised lithostratigraphy at member level is proposed for part of the Dinantian (former Calciferous Sandstone Measures) of the Cockburnspath Outlier. Three members, the Eastern Hole, Horse Roads Sandstone and Hurker Members are recognised in the Tyninghame Formation (Inverclyde Group). The Gullane Formation (Strathclyde Group) is divided into the Kip Carle and Heathery Heugh Sandstone Members, and the Aberlady Formation (Strathclyde Group) into the Cove Harbour, Bilsdean, and Longcraig Members. Each member is formally defined, type sections are assigned, and detailed measured sections presented. The members are unambiguous over half of the outlier where they are known at outcrop or in core. Generalized lithofacies interpretations show that these members represent channel sandstone and floodplain-crevasse deposits in a near-coastal fluvial–deltaic environment.
Origin of felsic sheets in the Scourian granulites: new evidence from rare earth elements
Authors: Rollinson Hugh
Published: January 2010

Synopsis

Felsic sheets within the Scourian granulites of NW Scotland are shown to be granites, trondhjemites and tonalites. Their origin has been extensively debated. Previously they have been considered to be either a product of anatexis of Scourian gneisses during granulite facies metamorphism, or part of a Scourian igneous complex which predated the granulite facies metamorphism. The trace element geochemistry of the felsic sheets is, however, incompatible with an anatectic origin. It is proposed that the felsic sheets were formed by the partial melting of a mafic source at > 15 kbar and that their origin is linked to that of tonalite–trondhjemite–granodiorite suites common in Archaean cratons.
Late Quaternary valley floor evolution in the lower reaches of Carradale, Kintyre
Authors: Tipping Richard , Carter Stephen , Haggart B. Andrew
Published: January 2010

Synopsis

Field mapping, air-photograph interpretation and levelling delineated five discrete terrace accumulations within the buried bedrock valley of lower Carradale, Kintyre. These have been deposited at times from the Late Devensian (Dimlington Stadial) to the present day. The terraces are named from type localities. Two terrace surfaces can be related to prominent raised beach formations fronting the coast, a high-level beach at 12·30 m OD, inferred to be of Late Devensian age, and a lower and better developed beach at 7·90 m OD, of mid-Flandrian age. Radiocarbon dates on an estuarine fill related to the latter beach suggest maximum Flandrian sea-levels to have been attained after
c.
5800
14
C BP.

Incision due to falling sea-level from this highest Flandrian altitude commenced before
c.
4600
14
C BP. By that time, aggradation of the major fluvial fill in the valley was underway, and radiocarbon dates suggest that this terrace represented the active floodplain for over 4500
14
C years.
Former glacial lakes in the Dee valley: origin, drainage and significance
Authors: Brown Iain M.
Published: January 2010

Synopsis

Detailed geomorphological and sedimentological evidence is presented for a series of ice-marginal lakes in tributary valleys of lower Deeside. They developed during ice-sheet deglaciation due to damming by glacier ice which remained in the main valley. Drainage of these lakes occurred by both marginal and subglacial routes; in the latter case, the sudden outburst may be responsible for anomalously coarse flood deposits found downstream. It is argued that glacial lakes were a much more common feature of the deglacial landscape than recent reviews have suggested and their presence at the ice margin may have glaciological implications, as inferred by the often distinctive landform-sediment assemblages involved.
The peridotite plugs of northern Rum
Authors: Wadsworth W. J.
Published: January 2010

Synopsis

Minor intrusions of peridotite occur as plugs and dyke-like bodies within Torridonian country rocks to the north of the Rum Central Complex. These are collectively termed the satellitic plugs to distinguish them from three dyke-like apophyses (tongues) of peridotite which are contiguous with the main layered intrusion (intrusive peridotite plugs also cut the layered sequence locally). The satellitic peridotite plugs are characterized by their lithological uniformity, compared with the cumulates in the central complex. The only exception is the West Sgaorishal plug, which has a less mafic marginal facies, and also displays regular, but subtle, fine-scale matrix banding. This generally dips inwards at moderate angles from the near-vertical margins of the intrusion, and is locally colloform. The layering reflects relatively minor changes in the proportions of interstitial plagioclase and clinopyroxene. Mineral compositions, notably olivine (Fo
88–84
), are similar to those in the main cumulate succession. The tongues are petrologically similar to the satellitic plugs, and one of them displays the same type of fine-scale layering.

The satellitic plugs (and tongues) are thought to represent conduits emanating from the main subvolcanic magma chamber, that were filled with olivine-rich crystal mush displaced from the unconsolidated cumulus pile during major subsidence events, and lubricated by interstitial basaltic magma. The distinctive layering is attributed to a self-regulating oscillatory process affecting the nucleation of plagioclase and clinopyroxene in the intercumulus liquid; perhaps during unusually tranquil conditions.
Cornulatichnus:
a new trace fossil from the Old Red Sandstone of Orkney
Authors: Carroll Steven , Trewin Nigel H.
Published: January 2010

Synopsis

A large, sub-vertical, conical burrow,
Cornulatichnus edayensis
ichnogen. nov., ichnosp. nov. occurring in the Eday Marls and Upper Eday Sandstone of Orkney is described.
C. edayensis
occurs in both the massive sandy siltstone and in the laminated sandstone of the Eday Marls, suggesting excavation in a floodplain environment. A sub-aqueous origin is indicated by the presence of a well developed burrow lining and by the absence of cavities within the fill and of scratch-marks on the burrow walls. It is suggested to have been excavated as an open shelter burrow, possibly by an eel-like fish.
Middle Devensian ice-proximal gravels at Howe of Byth, Grampian Region
Authors: Hall A. M. , Duller G. , Jarvis J. , Wintle A. G.
Published: January 2010

Synopsis

Ice-proximal glaciofluvial gravels at Howe of Byth, Grampian Region, have given luminescence ages of 45 ± 4 and 37±4 ka BP. The gravels were laid down by meltwater draining from an ice margin in the Moray Firth and provide the first firm evidence of extensive glaciation in NE Scotland during the Mid Devensian.
Intra-continental rifting inferred from the major late Carboniferous quartz-dolerite dyke swarm of NW Europe
Authors: Smythe David K. , Russell Michael J. , Skuce Andrew G.
Published: January 2010

Synopsis

The late Carboniferous (Stephanian) quartz-dolerite dyke swarm of northern Britain extends eastwards from the Outer Hebrides on an arcuate trend for up to 200 km from the eastern UK coast, as far as the western margin of the Central Graben. The average trend of the swarm changes by about 45° between its western and eastern extremities. Individual dykes, which are generally up to 30 m wide onshore, attain widths of well over 1 km offshore. Magmatically and spatially, the swarm is closely related to the coeval Oslo Graben volcanic rocks and dykes of southern Norway, which lie on the extrapolation of the arcuate trend. The dyke trends point to a focus of relative tensile stress centred on the West Shetland Shelf region. Finite element modelling of the NW European area corroborates the stress-focusing hypothesis, which we interpret in the context of the major period of intra-continental rifting along the line of the proto North Atlantic (the Rockall Trough, Faeroe–Shetland Trough and eastern Norwegian Sea) at about 300 Ma. The regional distribution of Archaean and Caledonian lithosphere within Pangaea may account for the fact that both the dyke swarm and the Oslo Graben were located in northern Britain and southern Norway, rather than in the Faeroe–Shetland region.
Uppermost Telychian graptolites from the North Esk Inlier, Pentland Hills, near Edinburgh
Authors: Bull Elizabeth E. , Loydell David K.
Published: January 2010

Synopsis

The North Esk Inlier is an important outcrop of Silurian strata, well known for the abundance, quality and variety of fossiliferous material present. It records a significant segment of the sedimentary and tectonic history of the Midland Valley of Scotland. Numerous graptoloid specimens have recently been discovered and identified, and this has enabled the graptolite biostratigraphy of these deposits to be determined more accurately. The marine sediments of the North Esk Group have for many years been referred to as Upper Llandovery (Telychian),
Monoclimacis crenulata
Biozone age. The species now known to be present, are better and more precisely accommodated within the biozonal scheme of Bohemia, which is considered to be a refinement of the existing ‘British’ scheme, and correlation of relevant graptolite biostratigraphical schemes is considered. The sediments of the North Esk group are shown to range in age from the middle of the upper Llandovery
spiralis
graptolite interval, to lowest Wenlock. The graptolite species present are illustrated.