bluuebunny/crossref_metadata_2025 huggingface dataset:
Seismic velocities in the Lewisian metamorphic complex, northwest Britain—‘in situ’ measurements
Authors: Hall J. , Al-Haddad F. M.
Published: January 2010

Synopsis

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

Synopsis

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

Synopsis

Two spore assemblages from Ousdale and Sarclet in southern Caithness are described. The most likely age of the former is Lower Emsian, and of the latter Upper Emsian. At Ousdale a Lower Devonian age is indicated by
Pachytheca.
Glacial Geomorphology of the Dulnain Valley, Inverness-shire
Authors: Young J. A. T.
Published: January 2010

Synopsis

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

Synopsis

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

Synopsis

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

Synopsis

Evidence from thin sections, surface textures of separated grains, and from stratigraphic variations in the mineralogy of heavy-mineral concentrates, suggests an
in situ
origin for the red colour of Old Red Sandstone sediments. Haematite has been formed diagenetically from the break-down products of mafic minerals and increases as other heavy-minerals decrease in the older parts of the succession. Alteration was related to conditions of free circulation, over a relatively short period, of oxidizing ground waters in a warm climate. Two intervals of such weathering are recognized, one during the Lower Old Red Sandstone, the other during the Upper. The contribution of post-Devonian weathering seems to have been insignificant.
The petrology of the Dippin sill, Isle of Arran
Authors: Gibb F. G. F. , Henderson C. M. B.
Published: January 2010

Synopsis

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

Synopsis

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

Synopsis

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

Synopsis

The dinoflagellate cyst and benthonic foraminiferal analysis of the Quaternary sediments of borehole SLN 75/33 in the central-northern North Sea has resulted in the formulation of a climatostratigraphy which is believed to encompass sediments ranging in age from Ipswichian (Eemian) to Recent. Since the areal distribution of the organisms involved is thought to be controlled by water mass, an oceanographic history is attempted for the late Quaternary of the North Sea. This involves the penetration of North Atlantic water and the establishment of a homothermal water mass which allowed high percentages of “species of southern origin” into the area at times of strong climatic amelioration, and the loss of a North Atlantic influence during periods of climatic deterioration. Weaker ameliorations are more difficult to interpret but probably relate to some influence of North Atlantic water and a slight increase of water temperatures in relation to times of climatic deterioration, allowing only low percentages of “southern forms” into the area.
Recumbent folds between Glen Roy and Lismore
Authors: Hickman A. H.
Published: January 2010

Synopsis

Moinian and Lower Dalradian metasediments between Glen Roy and Lismore are folded by structures belonging to two main phases of deformation. D1 folds are isoclinal and regionally recumbent whereas D2 folds are tight to isoclinal and upright.

New information indicates that two structures previously regarded as major recumbent synclines can no longer be accepted as D1 folds. One, the Ballachulish Syncline, was postulated on false stratigraphic criteria and is considered to be non-existent. The other, the Appin Synform, is a D2 fold which locally refolds D1 isoclines, an example being the Balygrundle Syncline† on Lismore.

Recumbent folds up to 20 km in amplitude are confined to the area between Kinlochleven and Loch Treig where the Treig Syncline† underlines the Kinlochleven Anticline. Both these structures are refolded by the Blackwater Synform and the Inverlair Antiform†.

(†Structure described for the first time)
Correlation of metamorphic fabrics and the age of Lewisian metasediments near Loch Maree
Authors: Crane A.
Published: January 2010

Synopsis

Various views have been expressed concerning the age of the Lewisian metasediments and associated basites (Gleann Tulacha metasediments and Beinn Airigh Charr basite) near Loch Maree. Interpretation of their chronological status is complicated by:– (i) the absence of Scourie dykes intrusive in the metasediment-basite association. (ii) tectonic dislocation between the metasediment-basite outcrops and the surrounding gneissose complex.

Fabric analysis, with particular emphasis on shape-fabric anisotropy, shows that two NW–SE foliation-producing events in the gneissose complex were separated by Scourie-dyke emplacement. These foliations (coded S5 and S6) are respectively correlated with Late Scourian (Inverian) and Early Laxfordian structures elsewhere in the Lewisian.

Fabric and structural sequences in the metasediment-basite association are compared with those of the gneisses. It is concluded that Late Scourian metamorphism and deformation have affected the metasediments and associated basites. Similar findings were obtained from a narrow tract of metasediments and basites near Gruinard Bay (the Gruinard metasediment-basite association). These Gruinard rocks are probably the stratigraphical equivalents of the Loch Maree Group and contain S5 foliation cut by members of the Scourie-dyke swarm.

Absence of high grade Early Scourian (Badcallian) fabrics and structures in both the Gruinard and Loch Maree metasediment-basite associations is considered to be indicative of their post-Badcallian origin.

It is thus concluded that the metasediments near Loch Maree represent a post-Badcallian supracrustal cover which experienced penetrative metamorphism and deformation prior to Scourie-dyke emplacement.
A possible occurrence of
Remigolepis
in the topmost Old Red Sandstone of Berwickshire
Authors: Andrews S. M.
Published: January 2010

Synopsis

The occurrence of an incomplete fish plate of very large size in a loose block of Upper Old Red Sandstone at Pease Bay, near Cockburnspath, Berwickshire, is recorded. The bone is described, and identified as the anterior median dorsal plate of an antiarch (Placodermi),
?Remigolepis
sp., a genus hitherto known only from beds of debatable age (Famennian or Lower Carboniferous) in East Greenland and Australia. The British discovery may allow more accurate correlation with these beds, which bear very important vertebrate faunas including the earliest known land vertebrates, of which the ichthyostegid amphibians from East Greenland are best known. The actual age of these strata, however, remains to be evaluated. The possibility of amphibians occurring in association with
?Remigolepis
sp. in Berwickshire is considered extremely remote.
The limit of the Loch Lomond Advance in Glen Roy and vicinity
Authors: Sissons J. B.
Published: January 2010

Synopsis

The limit of the Loch Lomond Advance in an area extending from the Great Glen to the uplands around Loch Laggan is mapped and the evidence for the limit is described. In the north-eastern part of the area, despite high ground, only small glaciers were nourished. On part of the northern slope of the Ben Nevis range some corries lacked glaciers. In contrast major glaciers, up to 700 m thick, developed in uplands to the west and south-west and flowed into the area under consideration. Such differences imply pronounced contrasts in the distribution of snowfall and were a major factor in the development of ice-dammed lakes in Glen Roy and adjacent glens.
A Devensian Medial Moraine in Jura
Authors: Dawson Alastair G.
Published: January 2010

Synopsis

On the western side of Jura, there exists a remarkable 3.5 km linear suite of parallel boulder belts. The feature originates at 450 m O.D. at the western foot of Beinn an Oir, one of the Paps of Jura, and extends seaward to 30 m O.D. where it ends at a shallow lochan that lies at the junction between the feature and a high late-glacial marine shoreline. The boulder complex is composed in places of up to 4 parallel lines of dominantly angular Dalradian quartzite blocks (the local bedrock), each line rarely exceeding 27 m in width and 2.5 m in vertical thickness. The boulders, including several erratics, range from 0.2 to 1.3 m in length and are here interpreted as a large medial moraine that formed during the waning of the Devensian ice sheet in western Scotland.
Age of the Glen Dessary Syenite, Inverness-shire: diachronous Palaeozoic metamorphism Across the Great Glen
Authors: van Breemen O. , Aftalion Margaret , Pankhurst R. J. , Richardson S. W.
Published: January 2010

Synopsis

Apparently igneous zircons from the Glen Dessary syenite complex give concordant U-Pb ages averaging 456 ± 5 Ma which is taken to date crystallization. The complex was deformed and metamorphosed to amphibolite facies subsequent to emplacement so that this age is a maximum for these orogenic events in the western Moine Series. Other age data indicate that amphibolite facies conditions associated with pegmatite emplacement continued until ca. 430 Ma contrasting with the north-east Highlands where tectonism and metamorphism was completed by 460 Ma ago. The disparity between hornblende and mica K-Ar ages suggests that cooling from 500 to 300°C took about 20 Ma. Higher blocking temperatures are indicated for U-Pb in monazite and sphene than for U-Pb in apatite.
Palaeogeographical evolution of the Lower Old Red Sandstone basin in the western Midland Valley
Authors: Morton D. J.
Published: January 2010

Synopsis

Lower Old Red Sandstone rocks in the western Midland Valley form a red-bed sequence of probable alluvial origin. They accumulated in a NE-SW elongated basin linked in its early stages of development with similar depositional conditions in North Argyll. The basin, whilst changing its morphology with time, maintained a regional south-westerly dipping palaeoslope with deposition in a longitudinally draining floodplain environment replaced by laterally draining alluvial fans close to the inferred northern margins of the basin. A lithostratigraphy is proposed within which rocks are attributed to four distinct groups corresponding to those recognized in the NE Midland Valley. Within this lithostrarigraphical framework changes in sedimentation, palaeogeography and tectonic controls can be studied through time. The sedimentation time-trends suggest that along the northern margin deposition was controlled by faulting which, west of Loch Lomond, probably occurred along small normal faults shifting their location with time. Any extension of the Highland Boundary Fault into this western area was ineffective as a major feature either controlling deposition or defining the basin margins.
The Grampide Andalusite/Kyanite Isograd
Authors: Chinner G. A. , Heseltine F. J.
Published: January 2010

Synopsis

Separation of ‘regional’ from ‘contact’ andalusite in the vicinity of the newer granite intrusions of Aberdeenshire suggests that the andalusite/kyanite isograd runs as far south as Glen Callater before turning north east to pass along Deeside. The nature of the critical conjunction between this ‘solid’ isograd and the ‘dehydration’ kyanite isograd is still obscure but if we assume the Battock intrusion to have wedged the two apart, then both would dip to the north, the kyanite isograd surface therefore being inverted.
The chilled margin of the Ben Buie layered gabbro, Isle of Mull
Authors: Skelhorn R. R. , Henderson Paul , Walsh J. N. , Longland P. J. N.
Published: January 2010

Synopsis

The chilled margin is of tholeiite basalt composition, and the chondrite-normalized rare-earth element pattern is almost flat with a slight light rare-earth depletion. The composition has affinities with a number of other rocks in the Tertiary Igneous Province including some of the Preshal Mhor type dykes, Skye, and is further evidence for the possibly important role of high-calcium, low-alkali, tholeiite magma in the generation of major intrusions in the Province.
Tectonic contrasts in the Southern Uplands
Authors: Weir J. A.
Published: January 2010

Synopsis

The Southern Uplands Fault and the Ettrick Valley Fault define three tectonic domains exhibiting structural contrasts significant in elucidating the Caledonian tectonic history of the Southern Uplands. The Girvan area constitutes the northern domain, and is bounded to the SE by the Southern Uplands Fault. NW-verging asymmetrical folds and two generations of NW-translating thrusts are the dominant structures. The middle domain comprises the Northern Belt and the Central Belt southwards as far as the Ettrick Valley Fault. This domain is characterized by a series of listric faults, the Main thrust faults, associated with outcrops of Moffat Shales. These Main faults apparently cut NW-facing monoforms (
F
1
), and appear to be associated with SE-verging
F
2
monoforms. The faults display south-eastward translation, and culminations and depressions of plunge which may relate to the emplacement of igneous
plutons
. The southern domain includes the Southern Belt, and the outcrop of the Hawick Group immediately to the N.
F
1
folds prevail in this tract, and consist of NW-facing monoforms alternating with tracts of buckle folds, associated with steep strike faults considered to pre-date the Main thrust faults.

The significance of the contrasts rests firstly, in the dominance of listric faults in the middle domain, and secondly, in the confinement of these faults to a geographically restricted zone SE of the Southern Uplands Fault. The
F
1
structures are considered to have been formed initially by the buckling of a flysch cover in response to its
décollement
on an oceanic basement which was subducting north-westwards underneath the Laurentian continental plate. Continuing subduction generated an accretionary prism in
D
2
, defined by the successive south-eastward propagation of the listric faults, with complementary obduction of the Girvan foundation and its sedimentary cover. Later structures (
D
3
-
D
4
) are of lesser significance, and reflect a progressive deceleration of crustal shortening after the orogenic climax.
Structure of the Lower Palaeozoic rocks around Cairnsmore of Fleet, Galloway
Authors: Cook D. R. , Weir J. A.
Published: January 2010

Synopsis

The Lower Palaeozoic rocks around the Cairnsmore of Fleet pluton comprise representatives of the Moffat Shale Group, ranging from the Glenkiln or Lower Hartfell Formation (Llandeilo or Lower Caradoc) to the Upper Birkhill Formation (Fronian), conformably though diachronously overlain by greywackes of later Llandovery age. The Main folds (
f
1
) display two contrasting styles. Two tracts of northwestward dips, mainly steep and locally inverted, are separated by a tract of concentric folds, upright or overturned to the NW, with wavelengths mostly less than 500 m. The first phase concluded with the generation of complementary wrench fault sets, certain of which were subsequently reactivated. An episode of compressional faulting supervened, generating the southeastward-translating and strike-parallel listric faults of the Central Belt, of which four lie within the area. The tracts of steep NW dips were simultaneously modified by SE-verging open folds having axial planes with moderate SE dips (
f
2
). Later Caledonian movements, producing crossfolds associated with oblique-slip faulting (
f
3
) and kink bands (
f
4
), are of minor significance.
The geology of the Firth of Lorne, as determined by seismic and dive sampling methods
Authors: Barber P. L. , Dobson M. R. , Whittington R. J.
Published: January 2010

Synopsis

Marine studies in the Firth of Lorne have revealed the presence of heterogeneous basement and a constricted yet complex sedimentary basin. A total of forty three dive, dredge and borehole samples has allowed both the basement, which consists largely of Moinian, Torridonian and Old Red Sandstone, and the basin itself to be mapped.

Using the criteria first employed by Kennedy to identify the line of the Great Glen fault, the course of the structure is extended along the Firth. Divergent fault splays with normal throw probably emanate from the principal Great Glen structure and in turn control the size and nature of the basin. The fill includes proven Triassic and Jurassic together with probable Cretaceous and Tertiary and a complex Quaternary sequence. Permo-Triassic syndepositional movements and late Kimmerian adjustments, together with mid-Tertiary activity are thought to have been the main periods of movement affecting the region.
Structures at the south-western margin of the Glencoe fault intrusion on An-t-Sron
Authors: Bussell M. A.
Published: January 2010

Synopsis

Injection of early felsitic material was followed by the formation of an inward dipping coarse breccia zone with granitic permeations. A later phase of brecciation involved the injection of a mixture of fine-grained dioritic material and finely granulated schist, bearing abundant small schist fragments. Finally, the fault intrusion was emplaced as a crystal mush. A model of the intrusion process along this caldera hinge zone is presented, which involves the successive explosive advance of magmas from a gravity stratified chamber.
Surface features of heavy mineral grains from Palaeocene sands of the central North Sea
Authors: Morton Andrew C.
Published: January 2010

Synopsis

Scanning electron microscopy has revealed both mechanically and chemically produced surface textures on heavy mineral grains from Palaeocene sands of the central North Sea basin. Chemical activity initially modified irregular surfaces, producing mamillae. Further solution produced regular facets, the dimensions of which increase with intensity of etching. Variations in composition of the connate waters are thought responsible for slight variations in etching style.

Mechanically-produced surface features similar to those seen on quartz grains, including breakage blocks, V-shaped indentations, grooves, upturned cleavage plates and conchoidal fractures, mostly originated in a pre-Palaeocene phase of sedimentation. The possibility of retention of pre-existing surface textures on grains during the sedimentation process must therefore be considered when using such textures in palaeoenvironmental interpretation.
The Loch Lomond Advance on the Island of Rhum
Authors: Ballantyne C. K. , Wain-Hobson T.
Published: January 2010

Synopsis

On the Island of Rhum evidence is described for the former existence of eleven Loch Lomond Advance glaciers, nine in the Rhum Cuillin and two in the western hills, and is employed as the basis of a reconstruction of the area, volume, equilibrium firn line altitude and potential direct insolation received for each glacier at its maximal extent. Relict blockfields and associated large-scale patterned ground in upland areas not occupied by glacier ice during the Loch Lomond Stadial indicate that these areas were underlain by permafrost and subject to intensive frost action at this time. The distribution of the glaciers suggests that, as on the neighbouring island of Skye, the principal snow-bearing winds at the time of glacier accumulation were from the S. The balance between snowfall and insolation appears to have been most favourable for glacier accumulation in locations with aspects between W and NW and between E and NE.
Palaeogeographic setting of the Wrae Limestone: an Ordovician submarine-slide deposit in Tweeddale
Authors: Leggett J. K.
Published: January 2010

Synopsis

The Wrae Limestone occurs in association with alkaline lava and tuff as a thin horizon within Ordovician greywackes in Tweeddale. The limestone, containing a shallow-water fauna, occurs as clasts ranging in size up to large boulders several metres across, variously set in a muddy grit, clastic breccia, or tuff matrix. The greywackes of Tweeddale were deposited by mass-flow processes in deep water, and the limestone breccia was probably introduced into this environment by debris flow from a volcanic palaeo-high. The intimate association of tuff and limestone suggests that volcanic activity in the source area may have initiated the submarine sliding. Following recent plate tectonic models it is suggested that the original volcanic edifice is either not exposed at the present level of exposure in the Southern Uplands, or was not detached from the descending oceanic plate during subduction.

The Wrae Limestone occurs within a distinctive group of shaly mudstones and associated fine-grained and pebbly greywackes, known as the Lowther Shales. This unit is well-developed for several kilometres to the north of the Ordovician/Silurian boundary along a strip of the Northern Belt which extends from the Lowther Hills to the Moorfoot Hills. Sparse fossil evidence suggests that it is in large part of Upper Caradoc age. As with the majority of greywacke units in the Southern Uplands, biostratigraphic control is inadequate for the Lowther Shales association to merit formational status. On the grounds of its lithological heterogeneity, it is suggested that the unit is best renamed the Lowther Beds.
The stratigraphy of the Dalradian rocks around Loch Creran, Argyll
Authors: Litherland M.
Published: January 2010

Synopsis

An area of Dalradian rocks around Loch Creran, Argyll, has been mapped in detail. In this region
Bailey (1922)
produced a nappe model of two major Dalradian stratigraphic and structural divisions: the Ballappel Foundation and the Iltay Nappe—divided by the Iltay Boundary Slide. Later
Voll (1964)
interpreted these divisions as stratigraphic equivalents separated by a facies change.

The present work shows that the Dalradian rocks are composed of a single stratigraphic column with the ‘Ballappel’ rocks underlying the ‘Iltay’ rocks. The latter can be divided into two successions. The Ardmucknish Succession is the shallow water equivalent of the thicker Creran Succession, deposited on the northwest flank of the subsiding Dalradian trough. There are no nappe divisions, as defined by Bailey and no facies changes, as defined by Voll.
Distinctive pebbles as indicators of Dalradian provenance
Authors: Anderton R.
Published: January 2010

Synopsis

Ferruginous chert or jasper pebbles are described from the Jura Quartzite in Argyll. Very similar pebbles have been found in the Torridon Group and the Quartzite may therefore be partially derived from such late Proterozoic sediments. The ultimate source of the pebbles is considered to be an early Proterozoic iron-formation which lay in the area of the present Scotland-Greenland continental margin. The Jura Quartzite and other Dalradian psammites may have been derived from a largely sedimentary source area to the NW of their present outcrop, their mineralogical maturity resulting from sedimentary recycling. In contrast, the Port Askaig Tillite was probably derived from an igneous and metamorphic source area to the SE with the possible implication that the Iapetus Ocean did not start to open until Argyll Group times or later.
The geochemistry of Lewisian semipelitic schists from the Gairloch District, Wester Ross
Authors: Winchester J. A. , Park R. G. , Holland J. G.
Published: January 2010

Synopsis

The chemical composition of 63 samples of non-calcareous semipelitic schists from the Lewisian Loch Maree Group at Gairloch, Wester Ross is compared with that of 83 samples of the adjacent acid gneisses. The semipelitic metasediments can be clearly distinguished from the gneisses by their significantly higher Fe
2
O
3
(total), MgO, TiC
2
, Nb, Y, Zr, Zn, Cu, Cr and Ni contents, and lower concentrations of Al
2
O
3
, Na
2
O, Ba and Sr. These chemical differences can be used to distinguish sheared gneisses from sheared metasediments in certain transitional schist belts where the origin was formerly in doubt. Previous views that the semipelitic schists represented predominantly non-volcanogenic, greywacke-type sediments are confirmed, and the presence of two chemically distinct types representing different stratigraphic units is established. These metasediments are distinct from other Lewisian metasediments described in Assynt and Harris.
Basaltic macadam-breccias in the Girvan-Ballantrae Complex, Ayrshire
Authors: Lewis A. D. , Bloxam T. W.
Published: January 2010

Synopsis

Many supposed “volcanic agglomerates and tuffs” in the Girvan-Ballantrae complex of southern Ayrshire are considered to be non-pyroclastic in origin. These macadam breccias are accumulations of lava breccia derived mainly from the autoclastic disintegration of pillow basalts during, or shortly after, extrusion. The breccia-forming process is considered to be mainly a function of supercooling, glass formation and retention of volatiles, all of-which are directly related to external hydrostatic pressure.
Stratigraphy of the lower Calciferous Sandstone Measures in Fife
Authors: Browne M. A. E.
Published: January 2010

Synopsis

The Balcomie Beds of east Fife, formerly classified in the Upper Old Red Sandstone, are now considered to be of the same general age as the lithologically similar Downie's Loup Sandstones of Stirling and the Calcareous sandstones of west Fife. It therefore follows that Ballagan Beds (cementstones) may be present at depth at Balcomie. It is suggested that all three fluvial sandstone formations formed as a result of mid-Dinantian earth movements which caused a reduction in the size of the early Dinantian sedimentary basin.

In the extremely attenuated Calciferous Sandstone Measures sequence in the Lomond Hills a poor miospore assemblage supports the contention put forward on lithological grounds that only the Pathhead Beds of east Fife are present and that one or more major disconformities of mid-Dinantian age exist there.
On an exposure of the Ordovician
superstes
Mudstones at Colmonell, Girvan District, Strathclyde
Authors: Tripp R. P. , Williams A. , Paul C. R. C.
Published: January 2010

Synopsis

A small exposure of mudstones with nodular limestones has yielded a diverse shelly assemblage dominated by brachiopods and trilobites, but with a varied echinoderm fauna. Most of the trilobites occur in the basal
superstes
Mudstones of Aldons Quarry and nowhere else. The brachipods confirm that these mudstones are coeval with successions transitional between typical Stinchar Limestone and
superstes
Mudstones.
The Inner Moray Firth Central Ridge, a geophysical interpretation
Authors: Dimitropoulos K. , Donato J. A.
Published: January 2010

Synopsis

The Institute of Geological Sciences has acquired gravity, multichannel seismic and aeromagnetic data covering the Inner Moray Firth sedimentary basin. The seismic data reveal a Permian-Cretaceous sequence up to 5 km thick, in which the deposition was fault controlled. With the help of well data, the gravity effect of the sediments is removed to leave a residual anomaly of approximately −23 mGal. Once corrected for regional effects, this anomaly is interpreted in terms of a Devonian (Old Red Sandstone) basin and an underlying granite. The presence of the latter is consistent with magnetic data and may be the cause of an uplift in the centre of the basin.
Microfossils from the Aultbea Formation, Torridon Group, on Tanera Beg, Summer Isles
Authors: Zhang Z. , Diver W. L. , Grant P. R.
Published: January 2010

Synopsis

A biota of sphaeromorph and nematomorph cryptarchs has been discovered in a grey shale unit of the Aultbea Formation, on Tanera Beg, Summer Isles. The grey shale unit is 4.9 m thick but microfossils are contained only within very thin fine grained intercalated laminae. The composition and lithological association of the biota suggests sedimentological control of its character.
Mid Jurassic Stratigraphy and Facies at Brora, Sutherland
Authors: Hurst Andrew R.
Published: January 2010

Synopsis

The lithostratigraphy of the
Brora Coal Formation
is revised, so defining two new members, the Doll Member and the Inverbrora Member. A new section of outcrop, to the SW of the main outcrop, allows minor structural adjustments to be made to the line of the Brora fault. The sequence is interpreted as a fluvial sequence, initially dominated by freshwater, sideritic mudstones, passing upwards into organic-rich shales and coals. Some evidence of marine or estuarine conditions are found near the top of the sequence. The palaeoenvironmental significance of the sideritic beds is discussed.
Jasper pebbles in the Dalradian at the Highland Border
Authors: Henderson W. G.
Published: January 2010

Synopsis

Southern Highland Group (Upper Dalradian) conglomerates at the Highland Border contain subangular jasper pebbles, probably derived from a Precambrian iron-formation. The angularity of these pebbles suggests iron-formation rocks were formerly present in the source area for the Southern Highland Group. This source area is now concealed beneath the Midland Valley or possibly the Grampian Highlands. Jasper pebbles in the Torridon Group were probably derived from another, though petrographically similar, iron-formation to the NW of Scotland. Rounded jaspers in the Dalradian, therefore, are not distinctive of one particular source area, as has been recently proposed.
The ‘Pliocene’ gravels of Buchan: a reappraisal
Authors: Kesel Richard H. , Gemmell Alastair M. D.
Published: January 2010

Synopsis

Detailed investigations of the sedimentary characteristics and composition of the so-called ‘Pliocene’ gravels of Buchan reveal them to belong to lithologically distinctive units. One unit, called the Windy Hills Gravels, is composed of gravels containing 80 to 90 per cent rounded quartzite clasts set in a sandy matrix. The bedding characteristics, gravel imbrication and granulometric analyses indicate that this deposit is of fluvial or fluvio-glacial origin deposited by a flow emanating from a westerly or northwesterly source. The other unit, the Cruden Flint Gravels, is composed of flint and quartzite cobbles set in a sand to clay matrix with interbedded sands. This unit is considered to be of glacial and fluvio-glacial origin. Present evidence does not allow precise dating of the units, but they are suggested to be late Pliocene or early Pleistocene in age.
A revision of C. F. Davidson's arctic fauna from Inchcoonans Claypit, Errol, held by the Museum and Art Gallery, Perth
Authors: Graham D. K. , Gregory D. M.
Published: January 2010

Synopsis

Recent infilling of the Inchcoonans Claypit and the apparent scarcity of fossils in the Errol beds (Pleistocene) elsewhere in the type area have made Davidson's collection in the Museum and Art Gallery, Perth, especially valuable. The cold water fauna described by Davidson (Trans. Proc. Perthsh. Soc. Nat. Sci.,9, 58–68; 1932) has been re-examined and a revised list of species is presented. Microfaunas recovered from hitherto unprocessed clay samples in the Davidson collection are also listed.
The stratigraphy and faunas of the Upper Ordovician High Mains Formation of the Girvan district
Authors: Harper D. A. T.
Published: January 2010

Synopsis

Revision of the stratigraphy and faunas of the High Mains Formation at Girvan, SW Scotland indicates the presence of two distinctive shelly faunas, both interpreted as associations of the widely documented terminal Ordovician
Hirnantia
fauna; these occurrences confirm the correlation of the formation with the latest Ashgill Hirnantian Stage. Both sediment and faunal content may be taken to indicate a gradual regression of the late Ordovician sea in this area.
An occurrence of Lower Carboniferous lavas at Monksgrave (Powmill) near Dollar
Authors: Browne M. A. E. , Thirlwall M. F.
Published: January 2010

Synopsis

Volcanic rocks exposed at Monksgrave which were formerly assigned to the Lower Devonian Ochil Volcanic Formation are now assigned to the Lower Carboniferous Clyde Plateau volcanic rocks. The new correlation is made on the basis of chemical and lithological similarities of the Monksgrave rocks to Lower Carboniferous volcanic rocks in the neighbouring Cleish Hills.
Glossary of Scottish mineral species 1981
Authors: MACPHERSON H. G. , LIVINGSTONE A.
Published: January 2010

SYNOPSIS

A glossary of Scottish mineral species, listing some 443 mineral names, and containing 399 valid species has been Compiled to fulfil a long recognized need. Wherever possible x-ray diffraction and chemical data have been used in the selection of the species. Entries for the glossary have been derived from an extensive literature survey, examination of many specimens from various museums and from data provided by individuals. The value of museum collections in works of this nature is highlighted, for without them coverage would be inadequate. Modern nomenclature in reference works is used as a yardstick for species status, but in some instances personal decisions had to be taken regarding the status of certain minerals. The mineral lists of Heddle have been revised and are now accredited with 162 valid species; this forms the nucleus of the glossary. Entries follow a standard sequence of name, ideal formula, crystal system, assemblage and locality details, except for Heddle entries. The first, or earliest found, reference is given for minerals discovered after 1901. Some minerals well entrenched in the literature are unsubstantiated. The glossary is accompanied by a text and three appendices, viz, minerals grouped anionically; mineral groups; and minerals which were discovered first in Scotland. Some 15 per cent of the species listed in this glossary have not been recorded previously for the United Kingdom.
Tectonic sliding within the Moinian Loch Eil Division near Kinlocheil, W. Inverness-shire
Authors: Strachan R. A.
Published: January 2010

Synopsis

Recent mapping within the Moinian Loch Eil Division of West Inverness-shire has resulted in the erection of a lithostratigraphic succession for the Kinlocheil area which has been subdivided into psammitic, quartzitic and semi-pelitic formations. A series of tectonic slides have been identified within the lower stratigraphic levels of the Loch Eil Division. These slides formed at an early stage in the structural history of the Loch Eil Division, preceding major folding during the Grampian event. Sliding in the Na-h-Uamachan-Gulvain area, north of Loch Eil, has resulted in the interleaving of Glenfinnan and Loch Eil Division rocks. Structural considerations indicate that the stratigraphic level at which sliding occurred was probably controlled by an early-formed “steep belt” within a broadly sub-horizontal succession. Within this structure “older” rocks have been thrust over “younger” and vice versa during westerly-directed movement along slides.
Recent excavations at the Greensand locality of Moreseat, Grampian Region
Authors: Hall A. M. , Connell E. R.
Published: January 2010

Synopsis

Recent excavations at the Greensand locality of Moreseat, Grampian Region are described. The Greensand is thought to occur in several small, isolated, erratic masses. The erratics were probably derived from the Moray Firth basin and may have been glacially transported to the site prior to the Devensian cold stage.
Upper Old Red Sandstone sedimentation near the unconformity at Arbroath
Authors: Ramos Amparo , Friend Peter F.
Published: January 2010

Synopsis

Coastal exposures near Arbroath provide information about local sedimentation patterns of the Upper Old Red Sandstone (Late Devonian) and the relationship between these patterns and the underlying unconformity. Bluck's analyses of the morphology and internal structures of gravel and sand river bars have been used to interpret the conglomerates as the major components of river bars that formed on the edges of frequently shifting river channels. Sands accumulated as bar tails and also in overbank areas that seem to have formed preferentially in ‘shadow zones’ protected from channel action close to hillocks of bed-rock. Locally breccias accumulated near these hillocks and plugged steep-sided gullies that formed in the overbank areas. These gullies appear to reflect arid conditions and there are other features of the Upper Old Red Sandstone that support this conclusion.
Syn-depositional faulting and valley-fill breccias in the Permo-Triassic of Arran
Authors: Astin T. R. , Macdonald D. I. M.
Published: January 2010

Synopsis

Two outcrops of New Red Sandstone breccia at Brodick, Arran, are interpreted to be filling two steep-sided valleys. Valley formation is contrasted to the usual style of sedimentation of the enclosing Brodick Breccia, which was deposited on a low relief alluvial plain by a braided river system. The valleys are inferred to be a consequence of faulting creating local topography on the plain. The diagenesis of the New Red Sandstone breccia and the surrounding strata is described, to show that early lithification aided the formation of both steep valley walls, and the large blocks of sediment now filling the valleys.
Palaeocurrents and palaeo-environment of part of the Bearreraig Sandstone (Middle Jurassic) of Skye and Raasay, Inner Hebrides
Authors: Morton Nicol
Published: January 2010

Synopsis

Part of the Middle Jurassic Bearreraig Sandstone in Skye (Strathaird) and Raasay consists of cross-bedded sandstones and sandy bioclastic limestones with marine fossils. The cross-bedding sets are mainly planar or subplanar, but sometimes trough. Palaeocurrent directions were bimodal (approximately N–S) in Strathaird, and unimodal (to N–NE) in Raasay. The beds were deposited as tidal sand waves migrating parallel to the coastline, and possibly influenced in direction by the major Camasunary, Screapadal and Applecross faults. The great lateral variation in facies, apparently fault-related, is in marked contrast to the earlier (Toarcian) and later (Bathonian, Great Estuarine Group) situations in the Hebrides Basin.
Small scale syn-sedimentary faults in the Upper Jurassic ‘Boulder Beds’
Authors: Pickering Kevin T.
Published: January 2010

Synopsis

Syn-sedimentary faults are common in the Kimmeridge ‘Boulder Beds’ in Sutherland, NE Scotland. Various styles are recognised: (1) closely spaced normal faults, generated by earthquake shock waves or listric faulting in the basal region of sediment gravity glides; (2) isolated normal faults with soft-sediment dykes along fault planes, possibly due to hydraulic fracturing that relieved high pore fluid pressures; (3) isolated conjugate normal faults with the acute bisectrix oriented perpendicular to bedding, probably formed by sediment overburden pressures; (4) decollement surfaces along which sliding or slumping has occurred, and (5) isolated reverse faults or thrusts; (4) and (5) possibly resulting from shear stresses generated as a result of sedimentation on a relatively steep basin slope. Sediment draping is visible above most of the fault surfaces, indicating that failure occurred in the superficial sediment cover and affected packets of beds up to a few metres thick. Stereograms of poles to the fault planes indicate a NNE–SSW girdle, with a concentration of poles showing fault planes dipping at about 45° to the ESE: the fault plane orientations corroborate earlier interpretations of a southeasterly dipping basin slope.
Graptolite faunas from the Ballantrae ophiolite complex and their structural implications
Authors: Stone P. , Rushton A. W. A.
Published: January 2010

Synopsis

Graptolites from the Bennane Head area of the Ballantrae complex indicate ages ranging from lowest Arenig (Lancefieldian, with
Tetragraptus approximates)
to middle Arenig (Chewtonian). The distribution of the graptolite faunas strongly suggests a tectonic repetition of the sequence of lavas and interbedded clastic sediments in which they are contained. This throws some doubt on previous assumptions of an anomalously thick volcanic succession within the complex, a feature which has been widely quoted in support of the various proposals for its origin. Instead it seems likely that volcanic sequences of different ages and origins have been structurally juxtaposed. The origins of the older, lower-middle Arenig volcanics are confused but a younger, middle-upper Arenig sequence seems likely to be the product of an island arc. A phase of major thrusting intervened between the two volcanic episodes.