bluuebunny/crossref_metadata_2025_split huggingface dataset:
The geochemistry and significance of plugs intruding the Tertiary Mull-Morvern lava succession, western Scotland
Authors: Kerr Andrew C. 
Published: January 2010

Synopsis
The Tertiary plugs of north Mull and Morvern, can be divided into three broad groups; (1) trachytes and mugearites; (2) diorites and tholeiitic dolerites with < 6 wt. % MgO and; (3) predominantly tholeiitic dolerites with > 6 wt. % MgO. Two trachytic trends are discernible, a low-iron and a high-iron trend. However, only the high-iron trend is found within the Tertiary Mull lava sequence. The origin of these two differentiation trends may be related to the composition of the primary magma, with more tholeiitic magmas fractionating to produce the lower-iron trachytes. The more MgO-rich plugs are invariably tholeiitic and are chemically unlike any of the preserved lavas within the Mull succession. The absence of this composition and of the low-iron trachyte compositions within the lava succession suggests that these magmas were possibly erupted near the top of the lava pile and have since been eroded away. The plugs may have acted as substantial feeders of the lava succession during its later stages of formation, while in the earlier stages the lavas were probably erupted from fissures. The absence of plugs associated with the Skye lavas, contrasts with the Mull and Antrim lava fields, and may be due to the more-intermittent nature of the Tertiary volcanic activity on Skye.
Estimates of the eroded overburden and the Permian–Quaternay subsidence history of the area west of Orkney
Authors: Evans D. J. 
Published: January 2010

Synopsis
Due partly to the perceived lack of preservation of strata younger than Devonian in age, the area onshore mainland Scotland and that offshore occupied by the West Orkney Basin, has long been regarded as emergent or close to sea level since end-Devonian times. Boreholes drilled within the West Orkney Basin have revealed much of the assumed Devonian fill of the West Orkney Basin to be Permo-Triassic in age, questioning this long held view. The post-Triassic subsidence history of the basin remains unknown. Well 202/19-1 penetrated Triassic mudstones, from which sonic and density data may provide evidence of an eroded overburden and thereby information regarding the subsidence or burial history of the West Orkney Basin. The availability of just one borehole does not permit the establishment of a porosity-depth relationship (shale burial curve) for shales/mudstones within the basin. However, available data when plotted against published shale depth–density and depth–velocity curves, provide eroded overburden estimates of between 1.3 and 1.6 km for the basin. Additionally the deposition of 250 m of post-erosional Late Tertiary/Quaternary sediments indicates that the eroded overburden was 1.85 km prior to reburial, which it is suggested, represents a reasonable estimate of the total amount of eroded late and post-Triassic overburden. Absolute uplift of 1.75–2.25 km from end-Cretaceous to Late Tertiary times is then calculated for the basin in general. Implications arise for palaeogeographic reconstructions and the timing of Devonian age source rocks entering the oil window. In addition to hydrocarbon generation during Late Devonian–Carboniferous times, further phases would be likely during Permian–Cretaceous burial. The eroded overburden and absolute uplift values suggest the submergence beneath Cretaceous seas of areas long considered at or close to sea level since end-Devonian times. This includes large areas of the Scottish Highlands.
The stratigraphy and depositional context of a temporary exposure in the Anstruther Formation (Strathclyde Group), Anstruther Wester, Fife
Authors: Kassi A. M. , Weir J. A. , Browne M. A. E. , McManus J. 
Published: January 2010

Synopsis
A temporary exposure in the Anstruther Formation (Strathclyde Group: Viséan, Asbian) behind the now-demolished Anstruther Wester swimming pool uncovered 13 m of strata within a cyclical sedimentary succession. A total of 68 m of this succession were logged from an arbitrary 10 m below the base of the Johnny Dow’s Pulpit sandstone to 5.2 m above the Billow Ness Marine Band.
The measured section includes two complete and two incompletely measured cycles representing variations on a primitive ‘Yoredale’ pattern, in which the transgressive marine shale–carbonate shelf facies is largely suppressed in favour of upward-coarsening progradational prodelta and delta front, and aggradational delta plain facies.
Each cycle commenced in a non-marine to marginal marine coastal environment in which shales, thin dolostones (some oncolitic), and ‘musselband’ shales and dolostones were deposited (the mussels are non-marine bivalves). Shales were succeeded by progradational channelized delta front facies, and aggradational delta plain facies also including channel-fill sandstones, typically with pedogenic tops. Variations in cycle thickness relate partly to fluctuations in the supply of sand-grade sediment, and partly to contemporary subsidence, possibly related to tectonic processes.
Comparisons are made with the late Brigantian Lower Limestone Formation at St Monans, which together with the Anstruther Formation forms part of a transgressive megasequence initiated late in the Devonian with continental, alluvial, redbeds.
A geological perspective on the Stone of Destiny
Authors: Fortey N. J. , Phillips E. R. , McMillan A. A. , Browne M. A. E. 
Published: January 2010

Synopsis
The petrography of a sample detached from the Stone of Destiny during the late nineteenth century by the Geological Survey of Great Britain, is described. The observations are compared with past geological descriptions of the Stone of Destiny and speculation regarding its origin, and are set against new petrographic descriptions of samples of Old Red Sandstone lithofacies from Geological Survey collections. The lithology of the Stone resembles that of Lower Devonian sandstones from the Perth area. In particular, the texture, mineral assemblage and colour are similar to those of sandstones from the Scone Formation in the vicinity of Quarry Mill, near Scone Palace itself. It is thus possible that this area contains the bed from which the Stone was hewn, although comparable rocks may exist within other exposures of the Old Red Sandstone lithofacies in Scotland.
A welded pyroclastic deposit within the Dinantian Clyde Plateau Volcanic Formation, near Eaglesham, in the East Renfrewshire Hills of the Midland Valley
Authors: MacPherson K. A. T. , Phillips E. R. 
Published: January 2010

Synopsis
This paper describes the first recorded occurrence of a welded lapilli-tuff in the Dinantian, Clyde Plateau Volcanic Formation. The pyroclastic succession which is exposed near Eaglesham, in the East Renfrewshire Hills, comprises three principal units. The lowest, a coarse volcaniclastic breccia formed by mass movement, is overlain by two fining-upward sequences which grade from a basal pyroclastic breccia into lapilli-tuff. The fining-upward and bedded nature of these upper units, coupled with their lack of diagnostic features indicative of pyroclastic ash flows, has led to the conclusion that they are ashfall deposits. Each deposit probably represents an eruptive unit, with the basal breccia indicating a vent-clearing episode during the initial stages of eruption. The heterogeneously welded lapilli-tuffs from the lower of the two cooling units may, therefore, be interpreted as primary, welded ashfall tuff.
Laxfordian metamorphic conditions of the Palaeoproterozoic Loch Maree Group, Lewisian Complex, NW Scotland
Authors: Droop G. T. R. , Fernandes L. A. D. , Shaw S. 
Published: January 2010

Synopsis
The supracrustal rocks of the Loch Maree Group (LMG), which form a Palaeoproterozoic cover to the Scourian basement of the Lewisian complex, underwent amphibolite-facies regional metamorphism during the Laxfordian orogeny. Micro-structural studies indicate that the peak of metamorphism in both the Loch Maree and Gairloch outcrops of the LMG was preceded by at least one major phase of ductile deformation, recorded by annealed lineations and foliations and by inclusion trails in minerals. At Loch Maree, this involved intense WNW–ESE stretching. The metamorphic peak occurred statically and was followed by (i) intense top-to-NW shearing, recorded by mylonitic fabrics particularly associated with the Loch Maree Thrust and (ii) several generations of open folding. These retrograde fabrics and folds reflect tectonically-induced uplift and exhumation during late Laxfordian times.
Thermobarometric studies were undertaken on low-variance rocks that had experienced relatively little retrogressive deformation. A garnetiferous calc-silicate rock, an ironstone and two dolomitic marbles from the Gairloch outcrop yielded Laxfordian peak-metamorphic conditions of 530 ± 20°C and 6.5 ± 1.5 kbar consistent with the epidote–amphibolite–facies assemblages. In general, the mylonites of Loch Maree outcrop proved unsuitable for thermo-barometric work, but a protomylonitic garnet–staurolite–mica schist yielded peak-metamorphic conditions of 630 ± 30°C and 6.5 ± 1.5 kbar. Temperatures during mylonitization were still high enough to stabilize garnet (i.e. > 470°C) which recrystallized as tiny neoblasts in the mylonites.

The peak-metamorphic pressures imply burial of the supracrustal LMG to
c.
24 ± 5 km, requiring substantial early Laxfordian tectonic thickening of the crust. Thus the main phase of basement–cover interleaving occurred before the development of the mylonitic fabric marked by the Loch Maree Thrust. Geothermal gradients at the metamorphic peak were moderate (
c.
20–30°C km
−1
), consistent with metamorphism in tectonically thickened crust. Existing tectonic models for the Laxfordian fail to account for the tectonic burial of the LMG to mid-crustal depths.
Xenoliths of Southern Uplands ‘basement?’ in a lamprophyre dyke, Central Belt, Glenluce, SW Scotland
Authors: Floyd J. D. , Phillips E. R. 
Published: January 2010

Synopsis
Lamprophyre dykes intruding Gala Group (Upper Llandovery) metagreywackes in the Central Belt of the Southern Uplands commonly contain a few xenoliths, usually of quartzite or vein quartz. However, on the coast south of Glenluce, one dyke contains a suite of incognate xenoliths of foliated and non-foliated meta-igneous rocks in addition to quartz, meta-greywacke and cognate xenoliths. These incognate xenoliths may represent samples either of the basement underlying the Southern Uplands or dioritic/tonalitic intrusions emplaced at depth into the sedimentary cover.
The Glen Tilt diorite: crystallization, petrogenesis and relation to granitic rocks
Authors: Beddoe-Stephens B. 
Published: January 2010

Synopsis
The Glen Tilt diorite forms a significant component of a late Caledonian, calc-alkaline, predominantly granitic intrusive complex on the north-west side of the Loch Tay Fault. It intrudes Grampian Group and lowermost Appin Group Dalradian metasedimentary rocks. The diorite is massive and contains common to abundant hornblende, variable amounts of biotite and clinopyroxene and late-stage intergranular quartz and K-feldspar. Opaque oxide and titanite ar e minor components. Associated granitic rocks comprise biotite granodiorite/granite and muscovite-bearing leucogranite. Dominantly north-easterly trending porphyritic microdiorite dykes are common in the area and cut elements of the granitic plutons.
Petrographical, mineralogical and chemical variation in the diorite is the result of crystal fractionation and accumulation processes. Comparison with experimental studies together with thermobarometric estimates suggests the body crystallized at 2–4 kbar and under hydrous conditions; early clinopyroxene exhibits a reaction relationship with later crystallizing hornblende. Pressure estimates are consistent with phase assemblages developed in contact metamorphosed pelitic rocks. Bulk rock and mineralogical chemical comparison suggest the porphyritic microdiorite minor intrusions are co-magmatic with the main diorite.
Field relations and petrographical observations indicate that biotite granodiorite/granite is emplaced early in the intrusive sequence and that localized melt remobilization and back-veining accompanied diorite emplacement. Leucogranite probably occurs later in the intrusive sequence although the complex as a whole was probably emplaced in a short time span. The chemical compositions of the main plutonic elements suggest they are not directly related by differentiation of a common magma but more likely represent contribution s from differing mantle and crustal sources. The complex as a whole probably represented the site of a magma chamber that fed coeval Siluro–Devonian volcanism, the ascent of magma probably being focused along the Loch Tay Fault and an intersecting NW trending structure.
‘Where ignorance is bliss ‘tis a folly to be wise’ (Thomas Gray 1716–1761) – controversy in the basement blocks of Scotland
Authors: Bluck B. J. 
Published: January 2010

The Millennium Issue
The year 2000 is the Millennium year and it is appropriate that the Scottish Journal of Geology should mark it in some way. The Editorial Board feel that at this time, at the beginning of what is arguably its 4th century, it is important to bring out the unique and varied character of Scottish geology. After some discussion it was decided to invite short essays from scientists for whom the geology of Scotland has had a special importance and who have themselves had a particular influence on Scottish Geology.
We asked for personal approaches to what is significant about the geology of Scotland. In what way has it inspired? Is it because of the intrinsic importance of the discoveries made here or more simply the influence of the environment? We hoped that some contributions would take a more geopolitical view. How much influence has Scotland had on the development of the science of geology as a whole and is there anything left here to discover?
We have been delighted with the contributions we have received. A recurrent theme has been the influence of place and it is clear that many of our contributors are as aware of the scenery and their feelings about this important legacy as they are about the (in some ways) more mundane geological issues. Many have included a historical viewpoint, and have reminded us how great a part was played in the last century by observers in Scotland in putting the science of geology together from its diverse beginnings.
These contributions appear in both issues of this volume of the Journal and are identified by photographs of the authors and brief notes on their careers.
Platinum-group element mineralization within ultramafic rocks at Corrycharmaig, Perthshire: implications for the origin of the complex
Authors: Power M. R. , Pirrie D. 
Published: January 2010

Synopsis
Alloys and complexes of the platinum-group elements (PGE) Pt, Pd, Ru, Rh, Ir and Os occur as discrete platinum-group minerals (PGM) throughout the chromite-dominant lithologies of the Corrycharmaig ultramafic body. PGM are either enclosed by chromite or occur in association with secondary Ni sulphide (heazlewoodite). The PGM enclosed by chromite are large (up to 40 μm), euhedral and interpreted to be primary magmatic in origin. Those that occur in association with heazlewoodite are small (<2 μm) and appear to have partitioned into the sulphide phase during alteration and metamorphism and subsequently exsolved. The dominance of Ru, Ir and Os (Ir PGE or IPGE) suggests that either the Corrycharmaig protolith was enriched in these elements relative to Rh, Pd and Pt (Pt PGE or PPGE) or that primary PPGE have been removed from the system. Previous interpretations for the genesis of the Corrycharmaig body have included ophiolite complexes or, more recently, komatiitic intrusions. The nature of the chromite mineralization and chemistry along with the presence of large laurite (IPGE-rich) grains enclosed by chromite are more indicative of an ophiolitic origin.
Silurian cephalopods from the Pentland Hills
Authors: Holland Charles Hepworth 
Published: January 2010

Synopsis
The nautiloid cephalopod fauna of the Silurian rocks of the Pentland Hills, Scotland is described. Though fragmentary, the available material permits assignment to 14 genera, for 10 of which specific names are given. Nearly all of the material is from the Wether Law Linn Formation and mostly from its lower part. Implications as to stratigraphical age are discussed. The fauna of the Wether Law Linn Formation has something of a Wenlock flavour.
The significance of a Hastingsite granite in the Carn Chuinneag–Inchbae Complex
Authors: Harker R. Ian , Leahy Timothy 
Published: January 2010

Synopsis
The discovery of a late stage hastingsite gneissic granite in the Inchbae mass (possibly coeval with the riebeckite gneissic granite in the Carn Chuinneag mass) indicates that different physico-chemical conditions prevailed during the last granitic stages of the two masses. This, along with other evidence at the North and SE contacts, is in accord with a previous view that the Inchbae mass is at a different stratigraphic level (lower) relative to the Carn Chuinneag mass.
Igneous rocks of the Georgeton burn, Cleish Hills
Authors: Hamill Brendan J. 
Published: January 2010

Synopsis
Basaltic rocks in the Cleish Hills of Kinross-shire, previously described as lavas of the Clyde Plateau volcanic series, are shown to be later intrusions. This re-interpretation raises doubts about published correlations of these rocks and the possible origin of igneous rocks and breccias in the Loch Leven area during the period 325–295 Ma.
Late Devonian–Carboniferous tectonic evolution within the Firth of Forth, Midland Valley; as revealed from 2D seismic reflection data
Authors: Ritchie J. D. , Johnson H. , Browne M. A. E. , Monaghan A. A. 
Published: January 2010

Synopsis
Results of integrated seismic mapping, within the Firth of Forth in the offshore Midland Valley of Scotland, are presented and illustrate aspects of the subsurface structure and tectonic evolution of the Upper Devonian to Carboniferous succession. Evidence for three main phases of tectonic activity has been recognized: (1) Late Devonian to Dinantian fault-controlled subsidence; (2) basin-wide Silesian subsidence, localized inversion and growth folding; (3) Late Silesian dextral transtensional and transpressional strike-slip faulting. During the first phase of tectonic activity, the NNE-trending Mid Forth Fault is interpreted to represent a Late Devonian to Dinantian extensional fault, with a small, mainly Dinantian depocentre developed in the hangingwall block that has subsequently been inverted during Silesian times. A major Late Devonian to Dinantian depocentre also occurs in the hangingwall block of the NE-trending offshore continuation of the Crossgatehall Fault, although it remains unclear whether this mainly Dinantian depocentre was developed during pull-apart as a result of extension or transtensional strike-slip fault movement. The NNE-trending Leven Syncline and Mid Forth Anticline within the hangingwall block of the Mid Forth Fault are interpreted as Silesian synsedimentary growth folds that formed during the second phase of tectonic activity. The peak of this activity occurred during intra-Westphalian B to Westphalian C times. In the third phase, the ENE-trending Inchkeith Fault Zone is interpreted as a Late Silesian transtensional–transpressional strike-slip fault that dextrally offsets the axial trace of the Leven Syncline. Evidence from the Firth of Forth could provide support for regional tectonic models involving mainly dextral strike-slip fault activity during Devonian–Carboniferous times, or mainly sinistral strike-slip during Devonian to Early Carboniferous followed by dextral strike-slip during Late Carboniferous times, for the development of the Upper Devonian and Carboniferous succession. However, the latter model is preferred as it provides the more convincing explanation for our interpretation that the NNE-trending Mid Forth Fault represents a Late Devonian to Dinantian extensional or transtensional fault that was inverted during Silesian times. This inversion may therefore reflect a major change in the regional stress field.
The Loch Tay Fault: type section geometry and kinematics
Authors: Treagus J. E. 
Published: January 2010

Synopsis
The Loch Tay Fault in the Central Highlands of Scotland is the easternmost of six major faults that transect the Dalradian. Examination of the limited exposure along the sub-vertical fault walls in the type area demonstrates that it has undergone a history of left-lateral strike-slip as well as dip-slip. Evidence from the displacement of formation boundaries and of fold traces shows that the fault has undergone a finite history of 6.5–7.5 km of left-lateral strike-slip and a dip-slip, down to the NW, of 750–1000 m in the SW and central area, diminishing to 200 m or less in the NE. A major fault lens to the NW of the main fault (the Braes of Foss Fault Complex) has similarly undergone dip-slip (but down to the SE) and left-lateral strike-slip; however, two fault lenses to the SE of the major fault (the Glen Goulandie Fault Complex and a smaller lens to its SW) and associated splays have undergone right-lateral displacement. Displacements on the Frenich Burn Fault, a minor fault to the east of the Loch Tay Fault, are again dominantly left-lateral with small displacements down to the NW, whereas faults in an adjacent mine pit illustrate that displacements in the country rock are dominantly dip-slip. By analogy with the Tyndrum Fault, the main left-lateral and dip-slip movements are considered to be pre-Devonian, whereas the right-lateral and late extensional movements are interpreted as Carboniferous.
Air-fall tuffs in the Southern Highland Group, Dalradian Supergroup, at Birnam, Perthshire
Authors: Batchelor Richard A. 
Published: January 2010

Synopsis
Ten ‘brown beds’ representing air-fall tuffs in the Southern Highland Group of the Dalradian Supergroup of Scotland are described for the first time from near Birnam, Perthshire, close to the Highland Boundary Fault. Their composition suggests an origin more silicic than the traditional Dalradian ‘green beds’. Expressions of volcanism in the upper Dalradian are preserved as the Tayvallich (Argyll Group) and Loch Avich (Southern Highland Group) basaltic lavas. The Tayvallich lavas are associated with minor quartz keratophyre intrusions and pink felsic tuffs. On the basis of the currently accepted stratigraphic correlation of the upper Dalradian, the ‘brown beds’ at Birnam would have been derived from eruptions of currently unidentified quartz keratophyric magmas in Southern Highland Group times. Alternatively, if the source of the ‘brown beds’ can be traced to the Tayvallich volcanism, then the upper Dalradian stratigraphy of the Birnam area would need to be revised.