bluuebunny/crossref_metadata_2025 huggingface dataset:
The Lochnagar granitic ring complex, Aberdeenshire
Authors: Oldershaw W.
Published: January 2010

Synopsis

The Lochnagar granitic ring complex consists of nine concentric annular and crescentic masses of adamellite and granodiorite. The successive members of the complex were emplaced in order of increasing potassium and silica content and decreasing size and grain size from the margin towards the centre of the complex. The early members of the complex, the granodiorites and the first adamellite, are foliated and crowded with inclusions of the contiguous wall rocks. They are partly circumscribed by an adamellite cone sheet and appear to have been forcibly intruded into the complex. The later finer-grained adamellites appear to have been emplaced into the central part of the complex by cauldron-subsidence; the last two phases, the smallest, finest-grained and most felsic adamellites, being emplaced into the centre of the complex under flat roofs of earlier adamellite.
Triassic sedimentation and palaeogeography in Central Skye
Authors: Steel R. J. , Nicholson R. , Kalander L.
Published: January 2010

Synopsis

The Triassic sediments are described including a number of new localities which extend the known area of cover.

A new map shows the Mesozoic/Palaeozoic boundary at Camas Malag on Loch Slapin, where the basal Mesozoic sediments provide some critical evidence about the position of the latest Triassic and/or earliest Jurassic upland areas in central Skye.

Lateral and vertical variation in the Triassic facies, pebble size and composition of the conglomerates are plotted and show that there were two distinct physiographic environments:

an alluvial fan system which drained local Palaeozoic and Torridonian areas between Beinn an Dubhaich and Ben Suardal, and dispersed eastwards.

a floodplain system which drained a metamorphic region north-east of Broadford and dispersed south-westwards.

Their age relationship is uncertain, but local evidence suggests that they may have been penecontemporaneous.

The succession is seen to represent the youngest and the most easterly Triassic sedimentation in the Minch region. Regional thickness changes suggest that the Minch basin-complex enlarged eastwards, towards the Scottish mainland, through the Triassic Period.
Geophysical evidence on the nature of the Hebrides Terrace Seamount
Authors: Buckley J. S. , Bailey R. J.
Published: January 2010

Synopsis

A magnetic and seismic reflection survey of the Hebrides Terrace Seamount (56°28′N., 10°17′W.) is supplemented by gravity data obtained by the Ministry of Defence (Hydrographic Office). The Seamount has a guyot-like morphology, and is supposed to be a volcanic feature. Seismic reflection profiles suggest that it ante-dates a succession of sediments on the continental slope to which a tentative Eocene–Recentage is assigned; and there are indications that its flat summit may represent an erosional bevel coeval with a (?Palaeocene) phase of erosion of the adjacent continental shelf margin. The associated magnetic anomaly is complex and cannot be simply modelled, but its general character is consistent with the presence of basic igneous rocks emplaced during an epoch of reversed polarity. The gravity profile is consistent with a model invoking a deep-rooted cylindrical core of density 3.0 gm cm
−3
, flanked by pyroclastics and sediments of density 2.4 gm cm
−3
. Thus the assembled data tend to confirm that the Seamount is an early Cenozoic volcanic feature.
Organic remains and traces from the Dalradian of Benderloch, Argyll
Authors: Litherland M.
Published: January 2010

Synopsis

Organic remains from Dalradian slumped deposits, identified as oncolites, catagraphs and possible Bryozoa, are described. Correlation with organic forms from U.S.S.R. is noted. Borings into organic limestone clasts are mentioned and regarded as being due to parasitic algae.
The stratigraphy of the Callovian and Oxfordian stages (Middle-Upper Jurassic) in northern Scotland
Authors: Sykes Richard M.
Published: January 2010

Synopsis

Outcrops of Middle-Upper Jurassic rocks in northern Scotland are restricted to two sedimentary basins. In the east exposures at Brora (Sutherland) and Balintore (Ross-shire) are part of the Moray Firth basin. In the west major exposures at Staffin and in Strathaird (Isle of Skye) belong to the Minch basin. A formal lithostratigraphy is erected with five formations and twenty-six members, which have been correlated with the standard ammonite zone. Each basin presents a pair of sections, with thick sandy onshore sequences at Brora and Strathaird and condensed argillaceous offshore sequences at Balintore and Staffin. The two onshore/offshore localities show marked facies similarities, but are affected by different transgressions in the Oxfordian.

A new species of
Longaeviceras
is described. It is the first authenticated record of this genus from the Oxfordian.
Hapsidaulax
, new genus of dinoflagellate cysts from the Jurassic (Bathonian) of the Isle of Skye
Authors: Sarjeant William A. S.
Published: January 2010

Synopsis

A new genus of trabeculate dinoflagellates,
Hapsidaulax
, is described from the Middle Jurassic (Bathonian; pre-Discus Zone) of the Isle of Skye, Inverness-shire; it is characterised by a reflected tabulation entirely lacking cingular plate-equivalents and with seven precingular and six postcingular plates, a precingular archaeopyle being apparently developed. The single species currently assigned to this genus,
H. margarethae sp. nov.
, is described in detail and the variation in its morphology discussed. The stratigraphical and palaeontological significance of this new genus is discussed.
Lower Border Group (Tournaisian) limestones from the Northumberland Basin
Authors: Leeder Michael
Published: January 2010

Synopsis

Limestones in the Lower Border Group form parts of deltaic clastic-carbonate cycles. They contain a variety of grain types, including ooliths, algal grains and their derivatives and invertebrate bioclastic debris. A Q-mode cluster analysis of samples defines six facies: oolite–intraclast–peloid; oolite; bivalve–ostracod–peloid; intraclast; oncolite and brachiopod–crinoid–bivalve. An additional micrite facies is subjectively defined. The sediments were deposited in nearshore and offshore environments of the gulf-like Northumberland basin. Those of shallow subtidal origin are associated with stromatolites. Northward shelving of the gulf sea and bathymetric changes subsequent to periodic delta abandonments were the major controls upon the lateral and vertical successions of facies. Cements are dominantly of ferroan calcite composition, reflecting mudstone intercalations between carbonate members. Patchy ferroan dolomite is of late-diagenetic origin.
A re-interpretation of the deglaciation of Abernethy Forest, Inverness-shire
Authors: Young J. A. T.
Published: January 2010

Synopsis

Field investigations of the Abernethy Forest area, including large-scale geomorphological mapping, show that ice sheet wastage has produced meltwaters that have eroded and deposited sequences of fluvioglacial landforms whose patterns reflect the local topography and changing condition of the wasting glacier ice. Successively lower drainage outlets were utilised as the meltwaters sought out the most direct escape routes. Marginal drainage was never widespread and there is no evidence of former ice-dammed lakes.
Potassium-Argon evidence of a Permian age for the camptonite dykes: Orkney
Authors: Brown John Flett
Published: January 2010

Synopsis

Potassium-argon whole rock ages on three camptonite dykes from the west coast of the Orkney Mainland yield an average age of 245 ± 12 my. A possible correlation is suggested between these intrusions and the Permian alkalic intrusions of Oslo Fjord.
Sediment and macrofaunal distributions in the eastern Malin Sea, as determined by side-scan sonar and sampling
Authors: Pendlebury D. C. , Dobson M. R.
Published: January 2010

Synopsis

A bathymetric, sediment and macrofaunal analysis has been made of the eastern Malin Sea off the west coast of Scotand using shallow seismic, side-scan sonar, and the results from 53 bottom samples.

The distributions of the sediment types and the mobile bed-forms which reflect the prevailing hydrodynamic regime are presented in chart form.

An assessment of the relative contributions of the shelly macrofauna to the sediment has been made; in addition four major benthonic fauna/associations have been recognized.

The quantitative and qualitative details of the bottom fauna are summarized in table form. Total sediment analyses reveal that cool water limestones may be currently forming within the area.
The Moine Thrust and Moine Nappe at Loch Eriboll, Sutherland
Authors: Soper N. J. , Wilkinson P.
Published: January 2010

Synopsis

The western part of the Moine Nappe in north-west Sutherland consists of a thick belt of blastomylonite of greenschist facies overlain by non-mylonitic Moinian metasediments. It rests on a complex dislocation zone, the Moine Thrust Zone. A four-fold deformation sequence, similar to that established by earlier workers in the Moine Thrust Belt in Wester Ross, is described and interpreted in terms of repeated displacement of the orogen north-westwards relative to the Caledonian foreland. The composition and fabric of the mylonites are described; they are shown to have been derived from both the basement and cover rocks of the foreland. Evidence is adduced that the whole deformation sequence is of post-Cambrian age. Some regional implications are discussed.
The stratigraphy of the North Esk Inlier, Midlothian
Authors: Tipper John Charles
Published: January 2010

Synopsis

The stratigraphic succession in the North Esk Inlier is redescribed and four new formations recognized. These together form the North Esk Group. The lowest (Reservoir) formation is composed of more than 1000 m of alternating mudstones and siltstones, generally poorly fossihferous. The overlying Deerhope Formation is a sequence, up to 155 m thick, of cross-stratified sandstones, including one major conglomeratic interval. The 250 m thick sequence of highly fossiliferous siltstones forming the third (Wether Law Linn) formation contains several beds of volcanic ash, one of which is used to provide time-correlation throughout the inlier. The uppermost (Henshaw) formation is a red bed succession at least 740 m thick: apart from two fish beds it is unfossiliferous. With the exception of the Henshaw Formation which is, at least in part, Wenlock in age, the whole North Esk Group is considered to be of Upper Llandovery (Telychian) age.
The history of the Western Lewisian in the Glenelg Inlier, Lochalsh, Northern Highlands
Authors: Barber A. J. , May F.
Published: January 2010

Synopsis

A detailed field and petrographic study has been made of Lewisian rocks forming the western half of the Glenelg inlier. It is concluded that in this part of the inlier an earlier metamorphic and igneous complex was affected by Scourian metamorphism and intruded by a series of dykes (Scourié dykes) before the ‘Caledonian’ orogeny. There is no evidence of a Laxfordian event.

From the metamorphic and deformational episodes recognised in the adjacent Moines a sequence of Caledonian events is established for the rocks of the inlier. It is found that although the rocks have been texturally and mineralogically modified, the outline of their earlier Lewisian history and their essential Scourian characteristics have been preserved.

Correlation o f the later Caledonian events with the formation of mylonites in the Moine Thrust Belt supports the Precambrian age of the early metamorphic and structural events in the Moines indicated by isotopic age dating.
Potassium-argon ages for basic dykes from East Finnmark: stratigraphical and structural implications
Authors: Beckinsale R. D. , Reading H. G. , Rex D. C.
Published: January 2010

Synopsis

K–Ar age determinations for basic dykes from both sides of the Trollfjord-Komagelv fault zone of eastern Finnmark fall into three groups. Group A dykes occur on both sides of the fault zone, in the autochthon and in the Raggo and Barents Sea Groups. They are post-tectonic and give an age of 340 m.y. (Upper Devonian). Group B dykes occur in the Båtsfjord area of the Barents Sea region. They cut the thrust between the Raggo and Barents Sea Groups and give ages of about 640 m.y. One dyke (B2) from the Raggo Group, is cleaved and gives an age of 542 m.y. Group C dykes are syntectonic within the Barents Sea Group and give ages of more than 1,000 m.y. but the low potassium content of all but one (1,950 m.y.) dyke reduces the significance of these ages. The age of the Group B dykes shows that the folding and thrusting of the Barents Sea and Raggo Groups of the Båtsfjord area is significantly older than deposition of apparently similarly deformed Cambro-Ordovician of the autochthon. Therefore the Trollfjord-Komagelv fault zone separates two regions, with distinct early geological histories, possibly within different plates. Later, early Ordovician deformation, Silurian sedimentation and late Silurian/early Devonian deformation progressively affected both regions as movement along the fault zone from Ordovician to Devonian times brought the two regions together.
Sandstone-boulder conglomerates and a Torridonian cliffed shoreline between Gairloch and Stoer, northwest Scotland
Authors: Lawson David E.
Published: January 2010

Synopsis

A highly irregular and, in places, steep erosion surface overlain by sandstone-boulder conglomerate marks the angular unconformity where the Torridon Group overlies the gently dipping sediments of the Stoer Group. Intermittent exposures suggest a lithosome with an overall linear shape. Locally, infilled embayments and gorges with fossil relief over 30 m occur along the surface of the unconformity. The surface varies from smoothly stepped and gently bevelled with small runnels and channels to strongly bevelled and undercut to near vertical. Using size distribution, roundness and fabric the conglomerate is subdivided into chaotic, boulder and stratified ‘facies’. Size, shape and lithology of the clasts implies local derivation from the underlying Stoer Group and, in places within the chaotic facies where blocks reach 4 by 11 m, very little transport. Imbrication within the boulder facies indicates transport towards the fossil relief.

The nature of the unconformity, the apparent linear lithosome, alignment of large blocks along the cliff trace, local clast derivation, vertical and lateral fining away from the unconformity, imbrication and fabric, combined with heavy mineral bands and associated features of the sand portion of the stratified facies indicate erosion and deposition along a cliffed shoreline by a transgressing sea.

Some 70 m of sands and grey shales transitional between the conglomerate and the Applecross Formation are interpreted as beach and tidal flat deposits.
The Ettrick Valley Thrust and the upper limit of the Moffat Shales in Craigmichan Scaurs (Dumfries & Galloway Region : Annandale & Eskdale District)
Authors: Fyfe T. B. , Weir J. A.
Published: January 2010

Synopsis

The Moffat Shales crop out in the Selcoth Burn, a northwestward flowing tributary of the Moffat Water (Dumfries & Galloway Region : Annandale & Eskdale District) in a series
of schuppen
related to the southwestward continuation of the Ettrick Valley Thrust through Craigmichan Scaurs. These
schuppen
confirm the status of the latter as a major thrust carrying wedges of Moffat Shales southeastwards across higher beds of the Gala Group. The thrust is considered to have developed in relationship to a major
décollement
of Patagonian type. This
décollement
was itself probably controlled by the Moffat Shales.

Diagnosis of strata of higher
Monograptus turriculatus
Zone age in the Craigmichan Scaurs outcrop of the Moffat Shales indicates a continued southeastward ascent of the base of the flysch facies of the Gala Group, and suggests that the axial rise of the Moffat Geosyncline does not crop out within the Southern Uplands. The rise is probably concealed under, or involved with, the postulated
décollement.
Sedimentary sequences from the Upper Limestone Group of Northumberland
Authors: Elliott T.
Published: January 2010

Synopsis

The Namurian Upper Limestone Group on the Northumberland coast is dominated by a variety of clastic sedimentary sequences which accumulated in an interdistributary bay complex. Small-scale, current-dominated coarsening upwards sequences reflect repeated infilling of the bay by minor mouth bars, crevasse splays and levees. Associated with these sequences are minor crevasse channels and major fluvial channels, one of which is an easterly flowing low sinuosity channel characterised by transverse bars. Transgressive marine carbonate facies periodically interrupt bay sedimentation and are overlain by wave-dominated coarsening upwards sequences which resulted from beach-spit progradation at the bay mouth.
Palaeomagnetic dating of haematite genesis in Orcadian Basin sediments
Authors: Tarling D. H. , Donovan R. N. , Abou-Deeb J. M. , El-Batrouk S. I.
Published: January 2010

Synopsis

Stable directions of remanence in samples of the red facies of the Old Red Sandstone in the Caithness region correspond to a complex magnetisation mainly acquired in Carbo-Permian times. This indicates that haematite in these sediments formed or passed through a growth stage in late Palaeozoic Permian times that obscured most pre-existing magnetisation and was not seriously affected by any later chemical changes. The timing of this period of haematite growth illustrates the application of palaeomagnetic techniques to the dating of certain post depositional processes in sedimentary rocks and raises problems about the mechanism involved in such changes in the case of the Old Red Sandstones of northern Scotland.
A strain study of the Strathan Conglomerate, North Sutherland
Authors: Mendum J. R.
Published: January 2010

Synopsis

The Strathan Conglomerate lies in the Lower Moinian of Sutherland and has been strongly deformed by two events, f
1
and f
2
. Minimum finite strain values X:Y:Z, calculated from deformed pebbles, range from 51:44.5:1 to 32:25:1 respectively. The size, shape and composition of the pebbles is compared to the nearby undeformed Watch Hill Conglomerate of Old Red Sandstone age. A simple method for estimating the minimum finite strain is outlined.

The f
2
deformation has resulted in folding of the pre-existing flattened pebbles in some areas. During this folding and accompanying lower amphibolite grade metamorphism (M
2
) quartz migration to low stress areas has occurred, resulting in a strong f
2
lineation and quartz rodding, both parallel to the X axis of the f
2
strain ellipsoid. On Ben Hutig a similar event has occurred; pre-f
2
planar quartz veins form a series of rods when folded by f
2
folds. The consequences of these results are discussed.
Regolith development and modification on the Morven-Cabrach basic intrusion, Grampian Region
Authors: Dare-Edwards A. J. , Livesey N. T.
Published: January 2010

Synopsis

Investigation of the mineralogy of the regolith upon the Morven-Cabrach basic intrusion reveals that there is no glacial contamination, and hence little direct modification by the Pleistocene glaciation, above 450 m. There is evidence of intense chemical weathering of presumed Tertiary age and indication of severe periglacial physical activity in the Late Pleistocene, with minor alteration during the Holocene.
The Ballachulish rocks of the Blair Atholl District
Authors: Smith R. A. , Harris A. L.
Published: January 2010

Synopsis

A succession of quartzites, limestones and pelitic schists formerly correlated with various parts of the Dalradian Supergroup is described in stratigraphic order, determined by sedimentary structures. Lithological similarities indicate correlation with Ballachulish Subgroup rocks and sedimentary structures strongly suggest that the formations described are older than the Blair Atholl Subgroup of the type-locality.
The geochemistry of the Lewisian and Moinian of the Borgie area, North Sutherland
Authors: Moorhouse S. J.
Published: January 2010

Synopsis

The geochemistry of the Lewisian and Moinian of the Borgie area is compared and contrasted. Using various element plots (TiO
2
/SiO
2
,TiO
2
/total Fe, CaO/Y, CaO/Ce, Rb/Sr), it is shown that the Moinian and Lewisian are clearly distinguishable. Furthermore the Borgie Lewisian can be divided into Scourian and Laxfordian areas on the basis of characteristic element ratios (K/Rb, K/Sr, K/Ba, Rb/Sr, Ba/Rb), the wider implications of which are briefly discussed.
Different Moinian amphibolite suites in northern Ross-shire
Authors: Winchester J. A.
Published: January 2010

Synopsis

Two different suites of amphibolite with a basaltic composition occur in the Moinian of northern Ross-shire, where they are associated with pelitic schists. They may be distinguished both texturally and by their differing trace-element geochemistry. The Sgurr Mor amphibolite suite occurs as small schistose bodies in the Sgurr Mor pelite of Fannich Forest and similar schists elsewhere in northern Ross-shire; and the Meall an t-Sithe amphibolite suit comprises massive bodies widely distributed within the Meall an t-Sithe pelite occupying the core of the Fannich Synform.

Most of the trace-element differences between these amphibolite suites can be explained by the Sgurr Mor group consisting o f metamorphosed alkali basalts, and the Meall an t-Sithe group being metamorphosed tholeiites—a division which facilitates recognition of the separate stratigraphic divisions in the Moinian.

Both amphibolite suites differ chemically from the metamorphosed appinitic dykes which intrude all the Moinian divisions of the Western Highlands.
Trace Fossils from the Permo-Triassic of Arran
Authors: Pollard J. E. , Lovell J. P. B.
Published: January 2010

Synopsis

The first identifiable trace fossils recorded in the Permo-Triassic of Arran come from an exposure within the Auchenhew Beds near King’s Cave on the west coast. The forms cf.
“Siphonites”,
cf.
Cylindricum
and epichnial burrows, preserved in micaceous sandstones and mudstones, indicate the activity of an ephemeral invertebrate, probably arthropod, fauna in a shallow fluvial-lacustrine environment of unknown salinity. These trace fossil bearing sediments occur in a regional sequence of facies indicating an upwards change in environment from fluvial through aeolian and fluvial-lacustrine to marine.
The Loch Lomond Readvance in southern Skye and some palaeoclimatic implications
Authors: Sissons J. B.
Published: January 2010

Synopsis

The former existence of 13 glaciers is inferred, comprising 9 in the Cuillins and 4 in the Eastern Red Hills. For each glacier when at its maximal extent the area, volume and equilibrium firn line are determined, and the probable relative importance of direct insolation in the mass balances of the various glaciers is calculated. Glaciers that flowed S and SSW from the radiating corries of the Cuillins were larger and had much lower equilibrium firn lines than those that flowed N and NE, even though direct insolation was of sufficient importance to affect the distribution and size of end moraines. It is inferred that the principal snow-bearing winds were from the south, snowfall being much higher in the S Cuillins than in the NE. For the 8 external corries of the Cuillins there is a very high correlation between corrie volume and glacier volume, suggesting that the relevant climatic parameters had approximately the same relative values during the Loch Lomond Stadial as during numerous earlier periods of limited glaciation.
A Fossil Lobate Rock Glacier in Jura
Authors: Dawson Alastair G.
Published: January 2010

Synopsis

A detailed field investigation has been made of a lobate boulder accumulation at the foot of Beinn Shiantaidh on the island of Jura in the Scottish Inner Hebrides. The debris accumulation is interpreted as a fossil lobate rock glacier which formed during the Loch Lomond Readvance. The feature has a minimum volume of 185 000 m
3
and a backing cliff area of 20 000 m
2
. By assuming a maximum length for the Loch Lomond Readvance of 1000 years, cliff erosion during this period is estimated at 2.6–9.2 mm/yr. The morphological characteristics of the fossil feature are analogous to those of active lobate rock glaciers observed and measured elsewhere. The inferred climatic environment in which the rock glacier developed is incompatible with the view of Charlesworth (1955, pp. 881–3) that 19 valley glaciers developed in Jura during the Highland Readvance (generally considered equivalent to the Loch Lomond Readvance in the Western Highlands).
Anomalous glacial erratics in the southern part of the Outer Hebrides
Authors: Coward M. P.
Published: January 2010

Synopsis

On South Uist, in the Outer Hebrides, the Lewisian gneisses are of two distinct types. Glacial erratics from these indicate that during the latest glaciation ice moved from W to E, contrary to evidence of glacial movement o n the Scottish mainland.
A preliminary fission track dating survey of Caledonian “newer and last granites” from the Highlands of Scotland
Authors: Hurford Anthony J.
Published: January 2010

Synopsis

The published radiometric age determinations for Scottish Caledonian Newer and Last Granites are reviewed briefly. A short description is given of the theory and techniques of fission track dating. The results of 66 fission track determinations on sphene, zircon and apatite from 17 Newer and Last Granites from the Highlands are presented and their interpretation discussed in relation to previously published ages and the geology of the intrusions. The mean sphene date is 389 ± 8 Myr and the mean zircon date 387 ± 18 Myr; these dates are interpreted as the mean age of initial post-intrusion cooling. Dates from co-existing apatite are substantially lower, showing maxima of ∼ 230 Myr and ∼ 280 Myr. Various interpretations of the apatite data are suggested: the discrepant ages may result from either the slow cooling of the granites at a rate of ∼ 0.8°C/Myr, or from the partial or complete resetting of the dates by subsequent thermal events, or from a combination of slow cooling and resetting.
A possible submerged wave-cut platform in the Firth of Lorne
Authors: Hall J. , Rashid B. M.
Published: January 2010

[Synopsis]

Evidence is presented of a possible wave-cut erosion surface at about 30 m below sea level in the Firth of Lorne. Possible origins are discussed—an early-glacial age is preferred.
A Lewisian basement sheet within the Moine at Ribigill, north Sutherland
Authors: Moorhouse Steven J. , Moorhouse Valerie E.
Published: January 2010

Synopsis

A Lewisian basement sheet, consisting of hornblende and hornblende-biotite gneiss and amphibolite with a central zone of feldspathic migmatite, tectonically emplaced within the Moine is described using 98 major and trace element analyses of Lewisian and Moine rocks.

The Lewisian rocks are quite distinct from the unmigmatized local Moine metasediments and can be distinguished from a Moine pre-metamorphic basic intrusion (the ‘Ben Hope Sill’) which forms part of the boundary of the Lewisian sheet.

It is inferred, by comparison with published data, that the Ribigill Lewisian originally had a ‘Scourian-type’ geochemistry depleted in K, Rb, Pb, etc., during an early Lewisian high grade metamorphism. The rocks were retrogressed and migmatized during a later Lewisian event, with the introduction of Ce, Th, K, Rb, and possibly Na.

The Ribigill migmatites differ from published accounts of Laxfordian migmatites in several respects most notably in having high K/Rb ratios.
The date of deglaciation of the Paisley-Renfrew area
Authors: Browne M. A. E. , Harkness D. D. , Peacock J. D. , Ward R. G.
Published: January 2010

Synopsis

Marine shell radiocarbon ages from Late-glacial strata suggest that the Paisley-Renfrew area was deglaciated before 13 150 B.P.
(Arctica islandica).
A younger minimum date of about 12 000 B.P.
(Modiolus modiolus)
is explained by the fact that this species is epifaunal and was living on a foundation of gravel containing already sub-fossil
Arctica
shells.
Oxygen isotope studies on Cenozoic temperatures, oceans, and ice accumulation
Authors: Hudson J. D.
Published: January 2010

Synopsis

The most successful application of oxygen isotope studies on fossils has been the elucidation of the relationship between temperature changes, glaciation, and the isotopic composition of the oceans during the Pleistocene, from analyses of planktonic and benthonic foraminifera. This work is now being extended into the earlier Cenozoic, and is revealing the history of the accumulation of the Antarctic ice, and much else about Cenozoic climates. A review of the principles, limitations and future promise of the method is given by critically comparing some recent contributions.
Correlation of the Scottish Upper Limestone Group (Namurian) with that of the North of England
Authors: Ramsbottom W. H. C.
Published: January 2010

Synopsis

Re-examination of goniatites described by Currie (1954) suggests that the base of the Arnsbergian (E
2
) Stage is at the base of the Orchard Limestone rather than at the Index Limestone as Currie supposed. The Calmy and Castlecary limestones are at the
E. bisulcatum
and
Cravenoceratoides nitidus
horizons respectively. The Plean Limestones are believed to be at the level of the
Ct. edalensis
beds of England and to fill a lacuna in the north of England at this level.
Jurassic (Toarcian to ?Bajocian) ammonites of the Shiant Islands, Outer Hebrides
Authors: Penn I. E. , Merriman R. J.
Published: January 2010

Synopsis

Ammonites from the Jurassic outcrop nearest to the United Kingdom continental shelf margin have been preserved despite Tertiary thermal metamorphism of, in some cases, pyroxene-hornfels grade. Their redetermination shows lower beds to belong to the Lower Jurassic, Lower Toarcian,
falciferum
Zone and the higher beds may be of Middle Jurassic, Lower Bajocian (Aalenian),
concavum
Zone age. Poor preservation and imprecise stratigraphical location of specimens prevent precise comparison of thickness with the sequence of NE Skye where equivalent beds are found in similar sedimentary facies.
The structure of the eastern part of the Insch Mafic Intrusion Aberdeenshire
Authors: Ashcroft W. A. , Munro M.
Published: January 2010

Synopsis

A ground magnetic survey and a programme of shallow drilling have enabled considerable revisions to be made to the position of the margin of the Insch mass at its eastern end and revealed that the distribution and attitude of the igneous rock units have been strongly influenced by shear zones trendin g ENE.

New petrological information shows that, except in a restricted area, there is a lack of regular relationships between the cumulate igneous rock units and it is established that the major trends and discontinuities in the contoured magnetic map can be correlated with zones of shearing and mylonitization. Magnetic modelling indicates that the shear zones dip steeply (65–80°) to the south and that the mafic units extend no further than about 2 km in depth. Later faults on N or NW trends have also contributed to the disruption of the intrusion.

These findings are discussed in relation to regional structure and it is suggested that such shearing is more important than has been recognized hitherto and may constitute a discrete and extensive episode of deformation about 470 m.y. in age.
Dispersal of glacial erratics from Lennoxtown, Stirlingshire
Authors: Shakesby R. A.
Published: January 2010

Synopsis

Dry stone walls are used to trace fans of glacial erratics from outcrops of two small, adjacent but distinctive bodies of essexite near Lennoxtown, Stirlingshire. Contour maps of data point values representing erratic frequency in the walls reveal classic patterns of fans of erratics. A marked contrast in the rate of decline in the frequency of the two varieties in the walls down-ice from the outcrops is attributed to the difference in the spacing of joints in the two rock types. The action of crushing on the closely-jointed variety during glacial transport is believed to have produced erratics generally too small for wall-building within a short distance of the outcrop, whereas blocks of the more massively-jointed variety are still common in the walls up to 20 km from the source. Divergent flow of erratic-bearing ice is suggested as the main agent responsible for spreading erratics in directions at variance to that of general ice flow. Although inferences about glacial processes are made from the wall data, the restricted size range of wall stones has necessitated careful interpretation of the results.
The age of sediments on Foula, Shetland
Authors: Donovan R. N. , Collins A. , Rowlands M. A. , Archer R.
Published: January 2010

Synopsis

A spore assemblage dates the sediments on Foula as Middle Devonian (top Eifelian or lower Givetian).
Pollen chronology of the Glen Roy-Loch Laggan proglacial lake drainage
Authors: Macpherson Joyce Brown
Published: January 2010

Synopsis

Palynological evidence confirms that the Glen Roy-Loch Laggan proglacial lakes were impounded by ice of the Loch Lomond (Late Devensian) readvance. The highest stage of the lakes persisted until the time of the juniper pollen zone; the lowest stage had disappeared by the time of the beginning of the birch pollen zone. Drainage from the Pattack basin continued to discharge eastward through the Feagour, the lowest of the lake overflow channels, until the time of the birch-hazel pollen zone.
A complete Lower Dalradian succession in the Schiehallion district, Central Perthshire
Authors: Treagus J. E. , King G.
Published: January 2010

Synopsis

Remapping of the Schiehallion district of Central Perthshire has led to the recognition of a new succession, stratigraphically interposed between the Moine and the Blair Atholl “Series”. A description of the lithologies and comparison with type areas in the SW Highlands clearly shows that this succession comprises the Ballachulish and Lochaber Subgroups of the Lower Dalradian. The succession, although greatly compressed, is considered to be the most complete sequence of the Lower Dalradian yet described.
The geological significance of magnetic anomalies in the region of Islay
Authors: Westbrook Graham K. , Borradaile Graham J.
Published: January 2010

Synopsis

Upward continuation of the aeromagnetic map for the Islay region has been used to clarify the major anomaly caused by Lewisian rocks which are more strongly magnetized than the overlying metasediments. Interpretation of the magnetic anomaly indicates that the interface between the Lewisian and overlying rocks dips SE and flattens out under the plunge depression of the Loch Awe Syncline of SW Argyllshire, where the maximum present day vertical thickness of metasediments above the interface is estimated to be of the order of 15 km. This interface has played an important part in controlling the structure of the Dalradian rocks in this area, and it is likely that at depth the Loch Skerrols thrust runs along it.

A small prominent anomaly persisting in the upward continued aeromagnetic map may be attributed to a major Dalradian volcanic or igneous complex between Jura and the mainland.

The Loch Gruinart Fault, passing through the area occupied by the main anomaly, cannot be the continuation of the Great Glen Fault and probably has a net sinistral strike-slip component of only a few kilometres.
An Appalachian View of the Moine Thrust
Authors: Barton C. M.
Published: January 2010

Synopsis

Deformation in advance of the Moine thrust sheet was essentially in the cover, and was mechanically similar to that in the western Appalachians. Shearing along zones of décollement in the autochthon eventually guided the crystalline sheet into position. The décollement was not located within a single stratigraphic horizon, but rather, changed position along the strike of the fault. Steep fractures connected different glide zones and nucleated fold culminations during movement of the Moine sheet. The final shape of the Assynt culmination is a result of emplacement across an anticlinal fracture in the platform. Shortening normal to the direction of emplacement is required and may have been accommodated in part by small-scale folds which plunge down the dip of the fault.
Upper Old Red Sandstone near Kirkbean, Dumfries and Galloway
Authors: Leeder M. R. , Bridges P. H.
Published: January 2010

Synopsis

Two small inliers of Upper Old Red Sandstone facies near Kirkbean contain thin successions of alluvial redbed facies and pedogenic cornstones. The clastic deposits are thought to be derived locally, probably from the adjacent Criffel uplands. Lateral facies variations indicate deposition in small, isolated depositional hollows sculptured in Silurian greywackes. Deposition may have been at the same time or slightly earlier than the eruption of the basal Carboniferous Birrenswark Lavas along the northern margin of the Northumberland basin to the north-east and was finally terminated by basalt lavas covering the area.
Heavy mineral distribution in the Old Red Sandstone of the North-Eastern Midland Valley of Scotland
Authors: Braithwaite C. J. R. , Ali A. Jawad
Published: January 2010

Synopsis

Heavy minerals from the Old Red Sandstone in the eastern part of the Midland Valley of Scotland include haematite (grouped with
limonite and
goethite), ilmenite (with leucoxene), amphiboles, pyroxenes, garnet, staurolite, epidotes, apatite, rutile, tourmaline, zircon and monazite.

Although individual sources and transport paths cannot be recognized, the distribution of stable minerals demonstrates the presence of groups of streams draining particular families of source rocks.

The three older formations of the Lower Old Red Sandstone have insufficient outcrop to reveal any general picture, but the Arbuthnott, Garvock and Strathmore Groups have a number of well defined centres of distribution related to sources both north of the Highland line and, probably, to the east of the present coastline. One of these centres lay in the vicinity of Stonehaven and others to the west, notably near Blairgowrie. There is insufficient evidence to reach general conclusions on the Upper Old Red Sandstone.
Crystalline manganese oxides in till, from Bridge of Don, Aberdeen
Authors: Chew K. J.
Published: January 2010

Synopsis

Highly crystalline manganiferous blocks consisting mainly of manganite and pyrolusite occur in a supraglacial flow till. Field evidence indicates that mineralization, which is of high chemical purity and notably free of iron, occurred
in situ.
The segregation of manganese from iron probably occurred as a result of selective dissolution of manganese in waterlogged organic-rich soil or sediment. Manganese and associated barium may have been transported by groundwater to its present location largely in the form of colloidal hydrous manganese dioxide. Initial deposition appears to have been localized by impersistent clay bands, with further deposition being catalysed by previously deposited manganese oxides. Local topography and depth of the clay bands relative to a fluctuating water table were probably critical in localizing the mineralization.
Glen Garry vein complex
Authors: Fettes D. , Macdonald R.
Published: January 2010

Synopsis

The vein complex is one of several phases of late Caledonian igneous activity NW of the Great Glen. It post-dates the regional suite of microdiorites and the Cluanie Granodiorite. The veins which are massive and cross-cutting are predominantly of granodiorite composition although they range from quartz-diorite to leucogranite. Cross-cutting relationships consistently indicate that the more acid members are the youngest in the intrusive sequence. Major element analysis defines the complex as a chemically coherent suite which is readily distinguishable from other Caledonian calc-alkaline rocks. The complex has evolved by fractional crystallization. Major and minor element analyses as well as textural relationships indicate that the suite was dominated by fractionation of firstly hornblende and then plagioclase. Comparisons of this sequence with published experimental data and consideration of feldspar analyses suggests that the suite may have evolved at relatively high water pressures. The source of the parent quartz-diorite magma is problematical. The Moine host rocks are too silicic and too potassic. Also, trace element chemistry indicates some differences from published analyses of Lewisian basement rocks. Intrusion of the suite may be related to late Caledonian stresses associated with faulting on the Great Glen Fault.
An underwater television survey of facies variation on the inner Scottish shelf between Colonsay, Islay and Jura
Authors: Farrow George , Scoffin Terence , Brown Brian , Cucci Maurice
Published: January 2010

Synopsis

Using underwater television, eleven recurrent bottom facies have been identified and mapped over an area of about 250 km
2
. Bare rock areas are rare:
Turritella
-rich fine sands with trails, and crustacean-burrowed muds widespread. Coarse sands, fining northwards from megaripple fields in the Sound of Islay and the Passage of Oronsay are dominantly of biogenic origin. The kelp
Laminaria saccharina
was seen rooted in gravelly parts of the megaripple field in the former area (one of strong tidal currents but reduced wave action) where the calcareous alga
Lithothamnium
is an important contributor. Barnacles and molluscs dominate in the latter region, which is more exposed to Atlantic swell. Extensive spreads of
Modiolus
seem to rest on a tough clay surface, possibly of eroded late-Glacial material which also probably underlies Tarbert Bank, since it crops out along its eastern margin. The rippled sand body located on the Bank could represent residual out-wash.

Facies analysis by combined underwater television and grab/dredge/box coring is optimal for shelf waters of intermediate depth (10–100 m): it reveals particularly well vagile epifauna, normally missed by conventional grabbing. In addition, it permits sediment/faunal samples to be studied in a truer perspective.

Differentiation of facies by television scores over bottom sampling in higher energy, coarser sediments; but in lower energy muds and fine sands of the level bottom, where infauna dominate, biofacies analysis by faunal clustering and resin impregnation of internal structures will probably achieve greater refinement
Anatomy of a Lower Permian aeolian sandstone complex, Southern Scotland
Authors: Brookfield M. E.
Published: January 2010

Synopsis

Aeolian sandstones of Lower Permian age occur in the centres of fault-bounded intermontane basins in the southern Uplands of Scotland. At Locharbriggs, Dumfriesshire, three quarries expose vertical faces up to 20 metres high and 150 metres long in which the aeolian cross-lamination is cut by three different bounding surfaces of different hierarchical order. These surfaces indicate that the aeolian sandstones can be interpreted in terms of dunes climbing over larger bedforms called draas. Analysis of the cross-lamination and grain sizes show that the bedforms responsible for the strata were of transverse type with longitudinal elements.
A sequence of Lateglacial ice-dammed lakes in East Argyll
Authors: Ballantyne C. K.
Published: January 2010

Synopsis

During the period of glacial retreat that followed the Loch Lomond Advance maximum, a sequence of ice-dammed lakes formed in the Loch Tulla area of East Argyll, Scotland. The main evidence for this lake sequence consists of abandoned shorelines at altitudes of 332 m, 323 m, 319 m, 315 m and 248 m above sea level. These shorelines are restricted to the eastern part of the Tulla basin, and their altitudes correspond with these of local outlet cols. It is considered that the lakes formed on the eastern margin of a mass of downwasting glacier ice and did not occupy the entire basin, as has previously been suggested. The lowest lake probably drained englacially through the downwasting ice mass.
General structure of the Skye Tertiary igneous complex and detailed structure of the Beinn an Dubhaich Granite from magnetic evidence
Authors: Hoersch Alice L.
Published: January 2010

Synopsis

On the Isle of Skye, a series of Tertiary igneous rocks, including a central layered gabbro and associated granites occurs in an area of basement gneiss overlain by sediments of Cambrian to Cretaceous age. Two-dimensional computer modelling of aeromagnetic data (this paper) agrees reasonably well with the three-dimensional gravity model of Bott and Tuson (1973). Both models indicate that the gabbro pluton is a large, slightly cone-shaped mass, with a width of approximately 12 km at the top and 18 km at the base, penetrating to a depth of about 14 km, and that the granites are a shallow, near-surface phenomenon (less than 2.5 km deep), comprising about five to ten per cent of the total mass of the igneous assemblage.

The Beinn an Dubhaich granite is approximately 0.8 km wide and 3.2 km long in outcrop and contains numerous patches of limestone. Ground magnetic measurements and the relationship between the granite-limestone contact and the topography indicates that the granite is a stock which extends to depth and underlies the limestone. Further, the granite surface beneath the limestone is not smooth but rather consists of many lobes which intrude the limestone, possibly along pre-existing fractures.
The Early or Middle Devensian peat at Burn of Benholm, Kincardineshire
Authors: Donner J. J.
Published: January 2010

Synopsis

Radiocarbon assay of a sample of the Burn of Benholm peat gave an age of >42 000 B.P. This age and the stratigraphical position of the peat within the basal part of the till of the Strathmore glaciation places the peat in the Early or Middle Devensian stage. Pollen spectra show that the peat was formed in a tundra environment but do not give a more detailed dating of the peat.
Isotopic age determinations on the composite sill and associated olivine dolerite, South Bute
Authors: Buist D. S. , Ineson P. R. , Mitchell J. G.
Published: January 2010

Synopsis

K-Ar isotopic age determinations on the Tertiary composite sill indicate it is at least 56.3 ± 1.0 Ma old. The olivine dolerite sheet is likewise of a Tertiary age, with a similar age to the composite sill, and may be related to the crinanite sills of southern Arran. The whole almost certainly belong to the ‘Major Phase’ of igneous activity identified as occurring at 59 Ma in the British Tertiary igneous province.
Variations of strain and microstructure in folded Pipe Rock in the Moine Thrust Zone at Loch Eriboll and their bearing on the deformational history
Authors: Allison I.
Published: January 2010

Synopsis

Using deformed
Skolithos
pipes as strain markers, a folded sequence of Pipe Rock quartzites in the Heilam Nappe at Loch Eriboll is shown to have deformed dominantly by flexural flow. However, elliptical pipe sections on bedding evince a pre-folding strain. Microstructures observed in the hinge zone imply deformation dominated by the intercrystalline diffusion mechanism, pressure solution. On the limbs microstructural evidence for dislocation creep has almost obliterated features associated with pressure solution. It is concluded that the quartzite sequence deformed by pressure solution during an initial phase of layer parallel shortening and subsequently, when buckling was initiated and fold amplification occurred, the mechanism switched to dislocation creep. It is argued that this change in mechanism is related to changes in strain rate.
Evidence for a glacial readvance pre-dating the Loch Lomond Advance in Wester Ross
Authors: Robinson Mary , Ballantyne Colin K.
Published: January 2010

Synopsis

A series of lateral moraines and other ice-marginal features in the Wester Ross area of the NW Highlands is described. These total nearly 30 km in length, and indicate the former existence of a lobe of ice nearly 25 km in width across Lochs Gairloch and Ewe and the surrounding low ground. The ice-marginal features are interpreted as marking the limit of a glacial readvance that took place in this area sometime between the Late Devensian maximum of 17 000–18 000 B.P. and the onset of the Lateglacial Interstadial. The name Wester Ross Readvance is suggested.