bluuebunny/crossref_metadata_2025 huggingface dataset:
Transported graptolites and associated tool marks from Grieston Quarry, Innerleithen, Peeblesshire
Authors: Trewin Nigel H.
Published: January 2010

Synopsis

Graptolites transported by weak turbidity currents act as tools producing characteristic tool marks with impressions of thecae on bed bases. Graptolites are found preserved within the fine lamination of the D interval; generally associated with coarse silt or very fine sand. Both large unbroken stipes and debris of broken stipes are present; some sorting of the debris appears to have occurred during transport.
Monograptus drepanoformis
and
Climacograptus nebula
are recorded
in situ
from the quarry for the first time.
The base of the Lower Limestone Group (Viséan) in North Ayrshire
Authors: Wilson R. B.
Published: January 2010

Synopsis

A critical review is made of the evidence for correlating the Lower Carboniferous marine limestones of the upper Calciferous Sandstone Measures and Lower Limestone Group of the Paisley area with those of North Ayrshire. Of the three different schemes of correlation made in the past, one is supported by recently acquired palaeontological information from IGS boreholes. The main conclusion reached is that the Hurlet and Blackhall limestones of the Paisley area are respectively equivalent to the Broadstone and Dockra limestones of Ayrshire so that the base of the Lower Limestone Group should be drawn at the base of the Broadstone Limestone.
A fossiliferous lower Canadian (Tremadoc) boulder from the Benan Conglomerate of the Girvan district
Authors: Rushton A. W. A. , Tripp R. P.
Published: January 2010

Synopsis

A limestone boulder from the Benan Conglomerate (low Caradoc Series?) of the Girvan district yielded a few fossils of North American aspect, including
Clelandia reliqua
sp. nov., which are indicative of an early Canadian (Tremadoc) age. It is suggested that the boulder originated from a shallow-water limestone deposited on a land-mass on the SE margin of the Dalradian trough.
The Tertiary sediments of the Canna Basin, Sea of the Hebrides
Authors: Evans D. , Wilkinson G. C. , Craig D. L.
Published: January 2010

Synopsis

Analysis of the sediments recovered from a shallow borehole drilled into the Canna Basin, Sea of the Hebrides, has demonstrated that they are Upper Oligocene (Chattian) non-marine deposits. The basin is the most northerly of the presently known terrestrial Oligocene basins found on the western side of Britain.
A Tertiary igneous centre north of the Shetland Islands
Authors: Chalmers J. A. , Western P. G.
Published: January 2010

Synopsis

Marine gravity and magnetic data show the existence of a dense cylindrical body of approximately 14 km diameter centred at about 61°50′N, 00°30′W, north of the Shetland Islands. The density and remanent magnetization values derived for this body show it to be similar to the Tertiary basic intrusive bodies along the west coast of Scotland.
Palynological evidence of an early Portlandian age for the uppermost Helmsdale Boulder Beds, Sutherland
Authors: Riley Leslie A.
Published: January 2010

Synopsis

The Helmsdale Boulder Beds have for some years been cited in literature as being entirely of Kimmeridgian age. Recent palynological studies do, however, now indicate that the age of the youngest beds exposed in Navidale Bay is, in part, early Portlandian.
Lacustrine cycles, fish ecology and stratigraphic zonation in the Middle Devonian of Caithness
Authors: Donovan R. Nowell
Published: January 2010

Synopsis

Lacustrine Middle Devonian (Old Red Sandstone) sediments show climatically-controlled cycles resulting from the long-term rise and fall of lake levels in an enclosed basin. Lithologies present were deposited in deep (stratified), shallow and impermanent lakes. Varves, the common recurrence of specific lithologies and the cyclic growth of cosmoid fish scales suggest a marked seasonal climate. Fish faunas were subject both to minor seasonal controls and more profound long-term effects. When lake level was low the faunas may have died out. When the lake overflowed, population replenishment and/or exchange with neighbouring basins was possible. Consequently fish faunas show erratic distributions (involving sudden influxes and extinctions) and no undoubted phylogenetic lineages. Discrete faunal assemblages form internally correlatable “stratigraphic zones”.
Moine and Lewisian near the Great Glen Fault in Easter Ross
Authors: Rathbone P. A. , Harris A. L.
Published: January 2010

Synopsis

Two inliers of metamorphic rock—the Cromarty and Rosemarkie inliers—occur adjacent to the Great Glen Fault and within the Devonian sediments of Easter Ross. The Cromarty Inlier consists of striped psammitic Moine rocks, probably Glenfinnan Division, which have suffered high grade regional metamorphism and which have probably been locally transformed into mobilised granite. In the Rosemarkie Inlier, which corresponds to a well marked positive anomaly on the aeromagnetic map, Moine metasediments are accompanied by Lewisian hornblendic gneisses. The earliest of at least four episodes of deformation (D1–D4) is inferred to have interleaved the Moine and Lewisian while the Moine/Lewisian boundary was folded during three subsequent episodes. Granitic veins, including pegmatite, were emplaced in the Rosemarkie Inlier during or before the second deformation episode and carry intense D2 LS fabrics involving strains of 18:2.5:1 which have locally been modified during the third episode. Pegmatites and microgranites which occur in the Cromarty Inlier have not suffered comparable ductile deformation and postdate garnetiferous metabasic intrusions which are a feature of the Cromarty Inlier. Details of lithology and igneous history serve so to distinguish the two inliers that it is possible that, pre-D3, they were much further apart than at present.
Mineral reactions in a granulite facies calc-silicate rock from Scourie
Authors: Rollinson H. R.
Published: January 2010

Synopsis

A calc-gneiss from the type area of the granulite facies Scourian complex contains the mineral assemblage plagioclase (An
43–46
), scapolite (Me
63–65
, SO
4 26–30
), clinopyroxene, ilmenite-magnetite, rutile and minor amounts of pyrite, chalcopyrite, carbonate, uralite, sericite, quartz and apatite.

Mineral reactions can be written which define the maximum pressure and minimum temperature of the granulite facies metamorphism and stages in the cooling history of the rock. The distribution of Na and Ca between plagioclase and scapolite, calibrated by Goldsmith and Newton (1977) yields excessively high temperatures (c. 1200°C). This is revised using thermodynamic data from their experimental work and suggests a minimum temperature of 915°C for the granulite facies metamorphism; a maximum pressure of 11 kb for the metamorphism is obtained from the stability of plagioclase with respect to clinopyroxene and quartz.

Ilmenite-magnetite pairs equilibrated between 512° and 430°C and oxygen fugacity conditions were probably externally controlled. Ilmenite and clinopyroxene may have exchanged Fe and Mg to temperatures as low as 540°C, but at lower temperatures Mn replaces Mg in ilmenite.
Lewisian pyroxene gneisses from Barra and the geochemistry of the Archaean lower crust
Authors: Drury S. A.
Published: January 2010

Synopsis

Tonalitic, pyroxene gneisses from the pre- 2.6 Ga Lewisian complex of Barra are characterized by: (1) low K, Rb and Th; high Sr and Ba; high K/Rb ratios and low Rb/Sr and K/Ba ratios; (2) enriched light REE and depleted heavy REE; (3) positive Eu anomalies. These features, when considered in conjunction with evidence that a possible Archaean lower/upper crust interface may occur on Barra, are compatible with two models for lower crustal evolution: (A) the purging of hydrous tonalitic precursors in the lower crust of H
2
O and K, Rb and Th by mantle-derived, CO
2
-rich fluids carrying Sr and Eu during granulite facies metamorphism; (B) the primary igneous crystallization under high P

co
2

of new tonalitic additions to the crust, from which the hydrous residual melt fraction was expelled upwards. Pyroxene gneisses may be the repository of the extra Eu in the crust which is needed to complement the deficiency of that element in post-Archaean sediments and the upper crust.
The fluvioglacial landforms of mid-Strathdearn, Inverness-shire
Authors: Young J. A. T.
Published: January 2010

Synopsis

Glacier ice from the west overran Mid-Strathdearn and built up to become part of the SW–NE moving ice sheet that enveloped the Grampian Highlands 17–18 000 years ago. As the glacier ice wasted away, two contrasting networks of meltwater rivers evolved. Most of the glacial drainage flowed directly downhill and eventually joined the arterial channel of the fluvioglacial River Findhorn, although this route was not completely open to meltwaters until relatively late in the deglaciation. Other meltwater rivers followed ice-directed routes across the slopes and cut channels into intervening spurs and pre-existing cols. There was a major trans-watershed outflow of meltwaters from Mid-Strathdearn to the SE, and a lesser inflow of meltwaters from the NW.
Late-Devensian marine limits and the pattern of deglaciation of the Strathearn area, Tayside
Authors: Browne M. A. E.
Published: January 2010

Synopsis

In situ occurrences of fossiliferous marine clay up to 45 m O.D. in the Methven Depression between Crieff and Almondbank prove that this area, as well as the Earn Valley below Crieff, was deglaciated before the formation of the Main Perth Shoreline. Ice contact features around Almondbank and Dunning, previously thought to be associated with active ice-margins when this important shoreline was forming, were probably produced by local masses of dead-ice isolated by the earlier retreat of the Tay and Earn Glaciers. Following deglaciation a delta, which graded to a sea-level consistent with the minimum marine limit of 46 m O.D. at Strageath, developed in the vicinity of Crieff. Subsequently three series of terraces formed in response to the relative fall of sea-level brought about by the isostatic recovery of the land. The middle series is considered to be associated with the Main Perth Shoreline.
Lithostratigraphy of the Great Estuarine Group (Middle Jurassic), Inner Hebrides
Authors: Harris J. P. , Hudson J. D.
Published: January 2010

Synopsis

Revised lithostratigraphical terminology for the Great Estuarine Group in Skye, Raasay, Eigg and Muck is proposed. The group comprises the Cullaidh Shale Formation, Elgol Sandstone Formation with Kildonnan Member and Lonfearn Member, Valtos Sandstone Formation, Duntulm Formation, Kilmaluag Formation and Skudiburgh Formation. The type sections of these formations are defined, new measured sections of 5 of them are illustrated and their lateral variations described. The Group is predominantly Bathonian in age, having its base in the Garantiana Zone (Upper Bajocian) and its top in the Macrocephalus Zone (Lower Callovian). The mainly argillaceous formations show wide lateral continuity indicating that a single depositional basin must have occupied the Inner Hebrides—Minch area during the Bathonian.
James Hutton and Robert Jameson
Authors: Flinn Derek
Published: January 2010

Synopsis

In a recently published book “James Hutton's theory of the earth: the lost drawings” and in many accounts of Hutton including that in Geikie's “Founders of Geology” the failure of Hutton's theories to gain general acceptance for many decades after his death has been blamed on Robert Jameson. It is shown that Jameson's students had plenty of opportunity to learn of Hutton's theories which were rejected by many geologists of the time as too philosophical, and based on speculation. Huttonian theory was only later confirmed by field observation at a time when field observation and geological mapping were coming to be considered of paramount importance.
Trace element variation at the contact of the Dumbarton Rock basalt
Authors: Whyte F.
Published: January 2010

Synopsis

Ba and Sr decrease towards the margin of the plug and there is a pronounced concentration of Ba in the contact sandstone which may have been expelled by volatiles migrating from the basalt.
Floridiscus girvanensis
, a new Edrioasteroid (Echinodermata) from the Ordovician of Ayrshire
Authors: Smith A. B.
Published: January 2010

Synopsis

Floridiscus girvanensis
gen. et sp. nov. is described from the Ashgillian (Upper Ordovician) of Girvan, Ayrshire. Oral plating, ambulacral structure and hydropore arrangement link
Floridiscus
with the Lebetodiscidae, but the outward-flaring rosettes of peripheral rim plates are a pyrgocystid feature. It is suggested that the highly specialised
Pyrgocystis
evolved from an isorophid ancestor.
Rate of sedimentation in Kelly Reservoir, Strathclyde
Authors: Ledger D. C. , Lovell J. P. B. , Cuttle S. P.
Published: January 2010

Synopsis

Measurements made on the floor of the temporarily drained Kelly Reservoir indicate that sediment with a wet volume of
c.
2.7 × 10
4
m
3
was deposited there between 1895 and 1978. This corresponds to an estimated average rate of erosion in the catchment of
c.
41 tonnes km
−2
yr
−1
, or 1.8 cm per 1000 years.
On the age of the Donegal Granite
Authors: Fitch F. J. , Miller J. A.
Published: January 2010

Synposis

Argon–40/argon-39 step heating analysis of a muscovite concentrate from the pegmatitic facies of the main Donegal granite indicates an age of 400 ± 2 Ma (IUGS standard constants) for this important intrusive event in British Caledonian history. This suggests that the previously accepted Rb-Sr regression line age of 498 ± 5 Ma (
λ
87
Rb = 1.39 × 10
−11
y
−1
) may be in error.
A thrust fault at Welshman's Rock, Isle of Rhum
Authors: Emeleus C. H.
Published: January 2010

Synopsis

Evidence is presented for a thrust fault at Welshman's Rock, eastern Rhum. The thrust is considered to be the southern continuation of the western edge of the broad zone of Lower Palaeozoic thrusting seen on Skye. Possible implications for the distribution of rocks within the Rhum Tertiary Main Ring Fault are discussed.
p-forms from the Isle of Mull
Authors: Gray J. M.
Published: January 2010

Synopsis

Large numbers of well preserved p-forms occur along the southern shore of Loch na Keal on the Isle of Mull. The main forms are curved and sinuous channels up to 20 m long, 3 m wide and 1.5 m deep, but bowls, sichelwannen and other forms are also present. Field measurement of the orientation of 142 channels shows that they are consistently orientated parallel to the direction of ice movement as indicated by striae, and striae are present on the floors and sides of many of the channels. The mode of origin of the p-forms is discussed and it is concluded that meltwater erosion by corrasion and/or cavitation is the most likely process with active ice later moving through them. It may be significant that the p-forms occur along the former boundary zone between mainland and Mull ice.
A trimline method for defining the upper limit of Loch Lomond Advance glaciers: examples from the Loch Leven and Glen Coe areas
Authors: Thorp P. W.
Published: January 2010

Synopsis

Trimlines, indicated by marked contrasts between smooth ice-moulded and severely frost-affected bedrock surfaces, are used to map Loch Lomond Advance limits in an area extending from Rannoch Moor in the east, to North Ballachulish in the west. Supplementary evidence is provided by the distribution of hummocky moraines, thick till, erratics, fossil periglacial screes, lobes and terraces, and by abundant glacial markings. Reconstructed glacier surfaces indicate two large outlet glaciers flowing westwards towards Loch Linnhe from an ice cap on Rannoch Moor. The two glaciers were joined by ice flowing from numerous corries and tributary troughs.
Some aspects of intrastratal alteration of biotite in the Old Red Sandstone
Authors: Wilson M. J. , Duthie D. M. L.
Published: January 2010

Synopsis

Biotite separated from Lower Old Red Sandstone sediments of varying shades of redness has been characterized chemically, and by X-ray diffraction, infrared spectroscopy and optical microscopy, thus enabling an assessment to be made of the extent to which the mineral has been altered. It is concluded that alteration is still at a relatively early stage, although some of the biotites are quite highly oxidized. However, there is no evidence that the minerals have lost much, if any, structural iron, a finding inconsistent with the concept that the diagenetic alteration of biotite is important in the colouration of red beds.
Pressures of metamorphism in the thermal aureole of the Etive Granite Complex
Authors: Droop G. T. R. , Treloar P. J.
Published: January 2010

Synopsis

The Etive Complex was intruded into low grade Moine and Dalradian schists, including psammites, metabasites, calc-silicates and metapelites. Pressures of the contact metamorphism in the southern section of the thermal aureole have been calculated using an internally consistent dataset derived from published phase equilibrium data. Calculated pressures lie within the range 1.0 to 2.0 kb, corresponding to 3 to 6 km of overburden during intrusion. Pressures derived from a quartz-bearing metapelite, a SiO
2-
undersaturated metapelite and a calc-silicate are in good agreement both with each other and with regional constraints. The average rate of uplift between the Caledonian regional metamorphism between 475 and 500 Ma and the intrusion of the Etive Complex at about 400 Ma was 0.1 to 0.2 mm per year.
Probable Old Red Sandstone conglomerates around Tongue and adjacent areas, north Sutherland
Authors: Blackbourn Graham
Published: January 2010

Synopsis

Small outliers of conglomerate and sandstone occur on the N Sutherland coast at Kirtomy, Tongue and on the Roan Islands.

At Kirtomy sediment has infilled three N–S trending valleys cut into the Moine metasediments. The following three-stage depositional history is recorded in outliers near Tongue: (1) dissection of Moine and Lewisian terrain forming N–S valleys; (2) quiescence,
in situ
weathering of metamorphics, probable meandering rivers on alluvial plain; and (3) tectonic rejuvenation, thick conglomerate sequences laid down in braided rivers flowing north.

On the Roan Islands 350 m or more of coarse conglomerate was deposited by a braided river system flowing from the NW probably from uplands bordering the Orcadian Basin. A Lower or Middle Devonian age for all the outliers is preferred.
Riebeckitic arfvedsonite and aenigmatite from the Ailsa Craig microgranite
Authors: Howie R. A. , Walsh J. N.
Published: January 2010

Synopsis

The well-known Ailsa Craig microgranite has been found to contain aenigmatite as well as a riebeckitic amphibole; both minerals are extremely iron-rich and contain virtually no magnesium. Major- and trace-element analyses of the microgranite and of the two dark minerals by wet chemical methods are compared with results from an inductively-coupled plasma spectrometer.
Investigations into the Quaternary deposits and bedrock topography of central Glasgow
Authors: Menzies J.
Published: January 2010

Synopsis

Central Glasgow is an area dominated by the influence of glacial deposition. The landscape is a drumlinized till lowland and in areas close to the River Clyde, up to 26 m O.D., raised beaches were mapped at three distinct levels with patches of fluvioglacial deposits, peat and lacustrine-like sediments within interdrumlin hollows. Till partially covers the fluviatile sediments that infill the Clyde buried bedrock channel. Rockhead and drift thickness maps were constructed revealing the above deposits and their stratigraphic inter-relationships. The buried channel seems to have been cut subglacially and the infilling deposits deposited subglacially. Probably both events occurred prior to and/or during the last major ice advance into the area. The drumlinized till dates from this advance; the raised beaches from Lateglacial times.
Geological relationships within an Ordovician shale belt in Galloway
Authors: Stone P.
Published: January 2010

Synopsis

Several narrow, lenticular belts of black cherty mudstone and siltstone (the Moffat Shales), alternating with thick greywacke sequences, strike NE–SW across Galloway. One such belt is hornfelsed and considerably broadened near the SW margin of the Loch Doon granitic pluton. The broadening is caused by the interference of a major reclined fold (F
2
) with axis plunging SE, and earlier structures (F
1
) associated with a mélange-like fabric.

A third set of open folds (F
3
) with axes plunging steeply south is thought to have formed in response to the intrusion of the Loch Doon pluton. Major sinistral strike faulting followed by minor conjugate NW–SE and NNE–SSW faulting occurred between the F
2
and F
3
fold episodes.

A dioritic dyke swarm can be divided on structural evidence into four intrusive phases; pre-F
2
and probably pre-F
1
, post-F
2
but pre-faulting, post-faulting but probably pre-F
3
, and post-F
3
.
The Upper Brigantian (Lower Carboniferous) of Central Strathclyde
Authors: Whyte M. A.
Published: January 2010

Synopsis

The stratigraphy of the upper Brigantian (Lower Limestone Group and upper Calciferous Sandstone Measures) of the south-west margin of the Central Coalfield, of North and Central Ayrshire and of the Douglas Coalfield and Muirkirk Syncline is reviewed. The prolonged basal overlap of the upper Brigantian on to an upland area is seen to have been complicated by both gradual and intermittent tectonic activity. Sequences have thus been affected by a number of disconformities of varying extent and magnitude. A new correlation between Ayrshire and the Paisley district is proposed. The Dockra, Broadstone and Upper and Lower Old Mill Limestones of Ayrshire correlate respectively with the Hurlet, Blackbyre, Hollybush and Dykebar Limestones of Paisley. The major complication is associated with the supra-Dockra (Hurlet) disconformity which caused the Dockra Limestone to be exhumed over a wide area in Ayrshire. In the subsequent overlap of this surface the Blackhall Limestone transgression failed to reach North Ayrshire. The Hosie Limestones A–D of Ayrshire correlate with the Main to Top Hosie Limestones of Paisley. The disconformity at the Hosie Fireclay (Lillie's Shale Coal) position has caused the local erosion of Hosie Limestone B (Mid Hosie) and perhaps also of Hosie Limestone A (Main Hosie).
Depositional Environments and Palynology of the Devonian South-east Shetland Basin
Authors: Allen P. A. , Marshall J. E. A.
Published: January 2010

Synopsis

The sediments of the SE Shetland basin were deposited in six major depositional environments, (1) the breccias of basement screes, (2) the conglomerates of alluvial fans, (3) the sandstones and conglomerates of braided streams, (4) the fine-grained alluvium of high-sinuosity streams, (5) the clastic and carbonate deposits of lakes and (6) the sandstones of desert dunes.

Palynological evidence from the age suggests a stratigraphic position at or near the Givetian/Frasnian boundary and certainly younger than the Eday Flags of Orkney. Deposition may have occurred earlier in the northern part of the basin. Kerogen typing suggests the lacustrine environment was less evolved than Orkney and Caithness.

The Devonian SE Shetland basin occupied an elongate depression which was oriented NNW—SSE. A major drainage system flowed to the SSE and may have connected this basin to the larger Orcadian basin in the south. Prevailing winds blew up-valley to the north. Small lakes with shallow shoaling margins expanded and contracted in this basin.
Geochemistry of the western part of the Moinian assemblage
Authors: Winchester J. A. , Lambert R. St J. , Holland J. G.
Published: January 2010

Synopsis

Comparison of chemical analyses of the principal units of the Morar Division suggest that the inter-relationship between psammites and pelitic rocks is dominated by mechanical rather than chemical processes. This conclusion is drawn from similar ratios of Fe
2
O
3
/MgO, K/Rb, K/Ba and Ca/Y, and dissimilar ratios of Ti, Nb and Zr to Fe. Rocks of the Glenfinnan Division differ from comparable members of the Morar Division in having higher Nb/P
2
O
2
and Nb/Y for any given Sr or Fe
2
O
3
/Ni ratio, and higher Sr/Y for any given SiO
2
level. These distinctions may reflect consistent differences in the ratios of quartz and feldspar, ferromagnesians, and accessory minerals. Samples from the Loch Eil Division tend to have higher Zr/P
2
O
5
, Y/P
2
O
5
, CaO/P
2
O
5
, Rb/Sr and lower Ca/Y and K/Rb than their counterparts in the Morar and Glenfinnan Divisions. The Morar Basal Pelite has an immature chemistry showing affinity with the Lewisian basement upon which it rests. It can be distinguished from other Moinian pelitic units by its high Sr/Y. Certain individual psammitic horizons can be distinguished by their contents of P, Ti, Nb and Zr, and sometimes by Cr/Fe. The Morar Division has a chemistry consistent with deposition in a basin close to its supposed Lewisian source. In contrast, the Loch Eil Division may have been partly derived from a (post-Lewisian) sedimentary source, and may rest unconformably upon the underlying Moinian rocks.
Geothermometry and geobarometry of Dalradian metapelites and metabasites from the Central Scottish Highlands
Authors: Sivaprakash C.
Published: January 2010

Synopsis

Temperatures and pressures of metamorphism have been estimated for a suite of Dalradian garnetiferous mica schists, calcareous pelites, and hornblende schists (‘Green Beds’) from Central Perthshire. Garnet-biotite, calcite-dolomite, and muscovite-paragonite geothermometers indicate temperatures ranging from about 500°C, corresponding to the lowest grade, to a maximum of about 580°C, corresponding to the highest grade. Garnet-kyanite-plagioclase-quartz, and epidote-plagioclase-garnet-quartz equilibria indicate pressures of 8–11 kb. These temperature, pressure estimates agree well with the experimentally determined phase stabilities. A thermal gradient of 60–65°C/kb (20–22°C/km geothermal gradient) characterizes this area.
Devonian calcretes (cornstones) near Tain
Authors: Donovan R. Nowell
Published: January 2010

Synopsis

A calcrete (cornstone)-bearing sequence at Port an Righ on the Tarbat Peninsula is probably of Upper Devonian age. The sequence was deposited by braided pebbly streams flowing to the northeast. The calcretes indicate a semi-arid climate and geomorphic stability.
The Bajocian ‘Cornbrash’ of Raasay, Inner Hebrides: palynology, facies analysis and a revised geological map
Authors: Bradshaw M.J. , Fenton J. P. G.
Published: January 2010

Synopsis

The ‘Cornbrash’ of Raasay, so long an enigma of Upper Bathonian facies reconstructions for the Inner Hedrides, is shown to be of late Bajocian (
subfurcatum
Zone) age. Informally renamed the Glam Sandstone, it forms the uppermost part of the Raasay Sandstone Member of the Bearreraig Sandstone Formation and correlates with similar facies on the neighbouring Isle of Skye. The palynofloras of the Glam Sandstone and strata of known late Bathonian–early Callovian age on Skye are compared.

The Glam Sandstone was deposited in a marine sand belt on an exposed shelf, and the coarse-grained terrigenous component reflects severe erosion of basin margins and surrounding hinterland during eustatic sea-level fall. Upward facies change to ammonitiferous shale reflects the late Bajocian global sea-level rise.

A revised geological map of eastern central Raasay is presented. NW-SE trending step-faults explain the repetition of the Middle Jurassic sequence across the island.
Old Red Sandstone sedimentation and deformation in the Great Glen Fault Zone, NW of Loch Linnhe
Authors: Stoker M. S.
Published: January 2010

Synopsis

An outlier of Old Red Sandstone, comprising the Camas Chil Mhalieu and Rubha na h-Earba Formations, crops out in the Great Glen fault zone, on the NW shore of Loch Linnhe. Formerly classified as Middle Old Red Sandstone (Middle Devonian), new evidence suggests that it may be Lower Old Red Sandstone (Lower Devonian). The Camas Chil Mhalieu Formation—a coarse scree breccia—is overstepped by the more extensive Rubha na h-Earba Formation, which is characterised by an interdigitating conglomerate/sandstone sequence. The conglomerate facies represents sheetflood deposition, whilst the sandstone facies suggests deposition on a braided alluvial plain. The two formations have been variably deformed; the scree breccias have been subjected to brittle faulting, while the conglomerate and sandstone sequence has been folded and overthrust. Sedimentation and deformation of the sequence is believed to have been fault controlled.
The distribution of graptolites in south–east Scotland, with notes on the fauna of Old Cambus Quarry
Authors: Strachan I.
Published: January 2010

Synopsis

The general distribution of graptolites in the south-east of Scotland shows Ordovician faunas along the northern edge beside the Southern Uplands Fault and progressively younger faunas to the south-east, Birkhill Shale faunas being followed by widely dispersed Gala Group faunas. South of Eyemouth the beds are unfossiliferous but match the Hawick sequence along the strike. Old Cambus Quarry yields a fauna of some eight species which are briefly described but most of the Gala Group localities have only 2 or 3 species. Beds with
Monograptus exiguus
and with
M. crispus
as sole species suggest that these are local occurrences in a region of rapid deposition and not single horizons repeated by folds or faults. The occurrence of an Ordovician fauna near Coldingham suggests that there is a major structural line in the southeast of the area.
Petrogenesis of Lewisian amphibolite dykes from Clashnessie Bay, Near Stoer, Sutherland
Authors: Sills Jane D. , Windley Brian F.
Published: January 2010

Synopsis

Six thin amphibolite dykes cut the c. 2 7 b.y. old Scourian gneisses in Clashnessie Bay, near Stoer, Sutherland. They have a different orientation to the Scourie dykes, a prominent c. 2.4 b.y. old tholeiitic dyke swarm. These amphibolite dykes were intruded, metamorphosed and folded some time between the end of the Scourian granulite facies metamorphism and the intrusion of the Scourie dykes. They are possibly associated with the Inverian period of folding and retrogression. They are chemically distinct from Scourie dykes and have a very uniform composition being low-K tholeiitic andesites with a SiO
2
content of 54–57 wt%. They could have formed from a tholeiitic magma by hornblende fractionation.
A gravity investigation of the deep structure of the Lewisian rocks of Gairloch, Wester Ross
Authors: Thompson M. W. H. , Westbrook G. K.
Published: January 2010

Synopsis

The positive gravity anomaly of 150 gu associated with the Lewisian metabasites of Gairloch has been investigated along two profiles with closely spaced observations. Models of the structure, constrained by the surface outcrops and measured rock densities, and which have an overall synformal shape, fit the anomaly well. They indicate that the metabasites extend to a depth of between 4 and 6 km, and are compatible with an interpretation of the Gairloch structure as supracrustal metabasites and metasediments folded and faulted into the basement gneisses on which they were originally laid down.
The structure of the Loch Creran Dalradian and a new model for the SW Highlands.
Authors: Litherland M.
Published: January 2010

Synopsis

The structure of the Dalradian rocks around Loch Creran is described in terms of NE-trending upright D1 folds becoming recumbent to the east, accompanied by a primary D1 swing to the SE at the head of Loch Creran. The rocks are cut by a major slide, the Benderloch Slide, which formed prior to the first cleavage, S1. D2, D3 and D4 deformation-events are also described but these have little effect on the D1 outcrop pattern. The major fault system has been revised.

The mapping reveals various objections to the regional structural model proposed by Roberts and Treagus (1977), and a new, simple, ‘mushroom’ model is proposed for the SW Highlands. This involves the presence of a deep-seated massif within the fold belt which controlled the regional fold pattern. The writer concludes by emphasising that the structure of the SW Highlands of Scotland is by no means established.
Late glacial sea-level changes and ice-limits in Islay, Jura and Scarba, Scottish Inner Hebrides
Authors: Dawson Alastair G.
Published: January 2010

Synopsis

Ice-marginal landforms produced at the edge of the last (Late-Devensian) ice-sheet in Islay, Scottish Inner Hebrides are described. A glacial stillstand is indicated by the central Islay moraine and is associated with a fall in the marine limit of
c.
12 m. Deglaciation occurred initially in western and central Islay and was associated with the formation of a series of raised coastal terrace fragments. Slightly later, western Jura was deglaciated. This was followed by the development of two prominent Lateglacial shorelines (LI and L2). The latter features decline in altitude SW from
c.
40 m in NW Jura to
c.
15 m in central Islay and possess regional gradients of 0.59 m/km and 0.56 m/km. The relative regression of the Lateglacial sea was accompanied in western Jura by the widespread development of beach ridges. Measurement of the ridge altitudes shows that in this area the relative retreat of the Lateglacial sea was uninterrupted by any major transgressions, relative stillstands or renewed periods of glacio-isostatic downwarping.
The stratigraphy and structure of the southern Monadhliath Mountains between Loch Killin and upper Glen Roy
Authors: Haselock Paula J. , Winchester John A. , Whittles Keith H.
Published: January 2010

Synopsis

Psammitic and semi-pelitic metasediments in the Corrieyairack and Loch Killin areas form part of the Grampian Division and underlie the Dalradian Leven Schist of Glen Roy. Two stratigraphic successions, the Corrieyairack and Glenshirra Successions, have been recognized which share a common structural and metamorphic history, although they are separated by a well-defined zone of high strain, here termed the Gair-beinn Slide.

An early foliation (S
1
) associated with the development of isoclinal F
1
folds and movement on the Gairbeinn Slide, is refolded by tight near-upright, NE-SW trending major F
2
folds, in particular the Corrieyairack Syncline. These structures are refolded by open F
3
folds with variably oriented axial traces.
A gravity slide in the lower coal measures at Swallow Craig, near Kirkconnel, Dumfries and Galloway
Authors: Kirk Martin
Published: January 2010

Synopsis

A NNW dipping listric normal fault affecting a 6 m stratigraphic interval and displaying evidence of syn-sedimentary activity is described from the Sanquhar Coalfield, and interpreted as a gravity slide.
Lower Carboniferous biota of Glencartholm, Eskdale, Dumfriesshire
Authors: Schram Frederick R.
Published: January 2010

Synopsis

The unusual biota of the Glencartholm Volcanic Beds, Lower Carboniferous of Scotland is restudied in the first overall treatment since the turn of the century. Examination of the large collections now housed in the IGS Edinburgh and the Royal Scottish Museum afforded a complete list of the biota (some species never having been previously recorded from Glencartholm) and relative proportions among species. Selective diagenesis has occurred, calcareous fossils being dissolved, but organic/phosphatic forms preserved. Attempts to re-excavate the original site proved only partially productive; however, a new locality for the Glencartholm biota is herein recorded.
The classification and chemistry of the Tertiary intermediate lavas of Northeast Ireland
Authors: Lyle P. , Thompson S. J.
Published: January 2010

Synopsis

On the basis of recent chemical analyses the nomenclature of the Tertiary intermediate lavas in Antrim is reviewed and the overall petrogenic relationships between all the Tertiary volcanic rocks in Antrim are assessed. The conclusion is drawn that the intermediate and acid lavas result from differentiation of the basalts along a tholeiitic trend via silica-saturated intermediate compositions. Therefore the use of the terms mugearite and trachyte as previously applied to the intermediate derivatives in Antrim should be discontinued and a tholeiitic nomenclature substituted.
Palaeomagnetic studies of the Torridonian sediments, NW Scotland
Authors: Smith R. L. , Stearn J. E. F. , Piper J. D. A.
Published: January 2010

Synopsis

This study covers thermal demagnetisation results from 172 localities distributed through the Upper Proterozoic Stoer Group and Torridon Group sediments of NW Scotland. Chemical leaching experiments and results from slump horizons confirm earlier studies showing that the bulk of the total NRM in these rocks resides in specularite grains and is related to deposition and/or initial lithification processes; in the Stoer Group and Aultbea Formation a considerable fraction of the remanence is held by magnetite. Thermal demagnetization partially, but not completely, removes that part of the small secondary remanence residing in the high blocking temperature fraction overlapping with the initial remanence. Demagnetization trends suggest that this secondary remanence is a composite one including both a Caledonian (
c
. 400 Ma) and a Tertiary/Recent component. The palaeopole estimates in stratigraphic order are: Stoer Group (main outcrop) 253°E, 46°N (A
95
= 10°), Stoer Group (Enard Bay) 263°E, 37°N (A
95
= 11°), Diabaig Formation 233°E, 17°S (A
95
= 21½°), Cape Wrath sediments 237°E, 37°S (A
95
= 16°), Lower Applecross Formation 230°E, 40°S (A
95
= 16½°), Upper Applecross Formation 212°E, 27°S (A
95
= 14½°), - Applecross Formation (Loch Maree), 231°E, 23°S (A
95
= 17°), Aultbea Formation (Coigach Area) 231°E, 12°S (A
95
= 8½°) and Aultbea Formation (main outcrop) 207°E, 7°S (A
95
= 17°). The sampled sections complement and extend earlier studies to define in outline the magnetostratigraphy of these formations, and show that the contact between the Applecross and Aultbea Formations is strongly diachronous.

The time-sequence of poles from the Lower and Upper Torridonian coincide with the Laurentian a.p.w. path at
c
. 1100 and
c
. 1040 Ma respectively and imply that deposition and magnetization of these sediments predated isotopic closure by
c
. 130 Ma (Stoer Group, Rb–Sr isochron 968 Ma) and
c
. 260 Ma (Torridon Group, Rb–Sr isochron 777 Ma). This supports the views that the Torridonian and Moinian rocks are broadly coeval.
Inter-relationship of igneous activity and thrusting in Assynt: excavations at Loch Borralan
Authors: Parsons Ian , McKirdy Alan P.
Published: January 2010

Synopsis

The western margin of the Loch Borralan alkaline complex is bounded, in part, by Cambrian quartzites mapped (in poorly exposed ground) as forming part of the Cam Loch klippe, and therefore lying above the Ben More thrust. Excavations show that these quartzites are not in thrust relationship to the igneous rocks, but that the igneous types, melanite-nepheline syenites and pyroxenites, are intruded into them. The simplest interpretation is that the main movements on the Ben More thrust were complete before the emplacement of the Loch Borralan complex.
A Laxfordian age from the Inishtrahull Platform, County Donegal, Ireland
Authors: Roddick J. C. , Max M. D.
Published: January 2010

Synopsis

40
Ar/
39
Ar step heating analysis of an amphibole concentrate from a metagabbro on Tor Beg, north of Inishtrahull and Malin Head in County Donegal, Ireland has yielded an age of about 1710 Ma for a major amphibolite facies metamorphic event. No significant isotopic re-equilibration within Precambrian times subsequent to 1710 Ma is recorded. Subsequent reheating probably reflects a Caledonian event.
John Playfair on a Glacial Erratic in the Isle of Arran
Authors: Tinkler K. J.
Published: January 2010

Synopsis

A careful reading of Playfair’s Illustrations of the Huttonian Theory of the Earth reveals that he identified a large granite erratic on the Isle of Arran as a specific example in Britain of the type of problem posed by the famous Jura erratics: massive granite blocks transported 90 kilometres from their source in the Mt. Blanc massif. Both Playfair and Hutton invoked glaciers, together with torrents, (flash floods and/or mudflows) as potential agents in moving such erratics together with the supposition that the mountains had been more elevated and the regional slopes more continuous. Both applied the idea to any granite mountains and Playfair gives a specific Scottish case. It is concluded that Playfair, and probably also Hutton, should be given credit for first extending the glacial idea to Scotland.
A lower Rotliegend Flora from Ayrshire
Authors: Wagner Robert H.
Published: January 2010

Synopsis

Plant impressions from a single locality in the Mauchline Volcanic Group at the base of the ‘New Red Sandstone’ show a pterophyllsphenophyte assemblage probably of early Permian (Autunian) age. Abundant fragments of
Lobatopteris geinitzii
are accompanied by less common remains of
Pecopteris pinnatifida, Pecopteris
cf.
monyi, Mixoneura subcrenulata
var.
gallica, Annularia stellata, Annularia
cf.
spicata,
and
Asterophyllites equisetiformis.
Comparison is made with the lower Rotliegend flora of eastern Germany, although
N. subcrenulata
var.
gallica
is known primarily from the Stephanian C of south-central France. A brief discussion on the lower Rotliegend/Autunian relationships is followed by comments on the sparse records of presumed lower Permian floras in Britain.
Reaction softening in mylonites from the Arnaboll thrust, Sutherland
Authors: Dixon John , Williams Graham
Published: January 2010

Synopsis

Mylonites from the Arnaboll thrust, NW Scotland show considerable evidence for having been produced as a result of reaction softening or reaction-enhanced ductility. The effect has been to degrade an original, coarse-grained, granitic Lewisian gneiss to an extremely fine grained mylonite. Grain size reduction which relates to increasing strain has been accompanied by both a mineralogical and chemical change. Notably, feldspar disappears to be replaced by a fine-grained muscovite plus quartz assemblage at the highest strain. Chemical analyses and mass balancing suggest that this change is related to the addition and removal of material during shear deformation along this ductile shear zone. This has aided the reaction softening process and, possibly, superplastic behaviour in the rocks which characterises the highest strain ultramylonites found at the Arnaboll thrust.
Note on the correlation of the Upper Limestone Group (Namurian) in south Ayrshire
Authors: Wilson R. B.
Published: January 2010

Synopsis

The correlation of the principal limestones of the Upper Limestone Group (Namurian) of south Ayrshire with the standard succession in central Scotland has hitherto presented great difficulty. Recent boreholes sunk by the National Coal Board in the New Cumnock area have provided faunal evidence which makes it possible to correlate the limestones from Douglas to the New Cumnock and Dalmellington areas of Ayrshire. The Index, Lyoncross, Orchard, Calmy and Plean limestones can now be recognised in south Ayrshire.
A gravity study of the eastern Berwickshire Devonian basins, SE Scotland
Authors: Lagios E.
Published: January 2010

Synopsis

The Eyemouth and Oldhamstocks Basins of eastern Berwickshire have been studied and the Bouguer gravity anomaly map of these areas has been interpreted. It is concluded that both basins are fault-bounded.

The maximum sediment thickness of the Eyemouth Basin may be as large as 1900 m and, from a three-dimensional model of the area, the throws of the Eyemouth and Coldingham Faults are calculated to be 600 m.

Two- and especially three-dimensional modelling of the Oldham-stocks Basin reveals a structure which extends eastwards into the sea with a sequence of synclines and anticlines, bounded on the west by the Innerwick Fault, the offshore continuation of which has been proved by IGS marine seismic studies. The thickness of the post-Silurian sedimentary sequence is about 1500 m and is expected to be even greater a few kilometers offshore, where the lowest gravity values occur. The Cove and Innerwick Faults bounding the main Oldhamstocks Basin have estimated maximum throws of 900 m and 600 m, respectively.

Finally, the Great Conglomerate of Monynut Edge, west of Oldhamstocks, has a thickness of about 400 m.
The distribution of hydrocarbon minerals in the Orcadian Basin
Authors: Parnell John
Published: January 2010

Synopsis

Shows of hydrocarbon minerals are widespread in the Old Red Sandstone of the Orcadian Basin. They are derived from lacustrine laminites within the basin. Hydrocarbon minerals resulting from local diagenesis occupy tension gashes and vugs in cherts and carbonate rocks. Other deposits occur in joints and mineral veins, particularly those relating to the Permo-Carboniferous intrusion of a monchiquite-camptonite suite of dykes and vents. Hydrocarbon minerals replaced sediments to a very limited degree.
The Cothall Limestone
Authors: Parnell John
Published: January 2010

Synopsis

The Upper Old Red Sandstone Cothall Limestone in Morayshire shows the concretionary and laminar structures typical of a mature calcrete. The calcrete is locally silicified and includes length-slow chalcedony, typical of alkaline environments. Segregations of barium-rich agaric mineral occur in the calcrete.
A late-Devensian Marine and Non-marine sequence near Dumbarton, Strathclyde
Authors: Browne M. A. E. , McMillan A. A. , Graham D. K.
Published: January 2010

Synopsis

A marine shell (
Mytilus edulis
) radiocarbon age from late-Devensian clays at 29.5 m O.D. at Dumbarton indicates that the lower Clyde area may have been deglaciated around 13 700 BP. The clays are succeeded by plant-rich, shelly, freshwater sediments which are in turn locally overlain by peat. On the basis of one of two radiometric assays of plant material, the non-marine deposits are considered to have formed much later, towards the end of the Loch Lomond Stade (c.10 300 BP).
Hydrothermal fluid pathways at the contact of the Beinn an Dubhaich epigranite, Isle of Skye
Authors: Dickin A. P.
Published: January 2010

Synopsis

Field observations and Sr and Pb isotopic evidence point to the existence of two phases of hydrothermal activity at the margin of the Beinn an Dubhaich epigranite. An early flux of magmatic fluids carried Pb and Sr outwards from the granite, passing along major channels in the Durness Limestone to form skarn deposits, but not penetrating into the body of the rock. A later inward flux of meteoric fluids carried Sr from the limestone into the margins of the granite, where it penetrated along small cooling joints and grain boundaries, causing minor contamination.
Altyre and Lethen Bar, two Middle Old Red Sandstone fish localities?
Authors: Andrews S. M.
Published: January 2010

Synopsis

The Altyre Collection of Middle Old Red Sandstone fishes (made by Lady Gordon Cumming between 1839 and 1842) contained many specimens initially described by Louis Agassiz in his
Monographie des Poissons Fossiles du Vieux Grès Rouge,
of 1844–1845. There is a contradiction in the literature as to whether this material came from Lethen Bar, Nairnshire as recorded by Agassiz or the Altyre Burn as stated by Murchison in 1859. Its recent curation together with related historical research, have shown that the collection was made at Lethen Bar and that Murchison was wrong, although it is difficult to pinpoint a good reason for his error. The strata in the Altyre Burn are
Upper
Old Red Sandstone and the small wedge of Middle Old Red, which was included in this area on the 1″/1 mile Geological Survey map on the strength of Murchison’s 1859 statement, apparently does not exist. The most probable location for the original quarry at Lethen Bar is deduced from historical sources, and a short account of its working is given.