bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pre-Seminulan Main Limestone of the Avonian Series in Breconshire
Authors: George T. Neville 
Published: October 2009

Summary

The Avonian Main Limestone underlying the
Seminula
Zone in Breconshire has hitherto been referred to the
Zaphrentis
, Lower
Caninia
, and Upper
Caninia
zones in apparently conformable but attenuated sequence, lithologically not greatly different from that of the South Crop in Glamorgan. A remapping of the eastern outcrops, however, shows that a widespread development of dolomites, supposedly equivalent in part to the “
laminosa
Dolomites”, is misleading as a guide to stratigraphy; and that thick oolites, variously ascribed to the “
Seminula
Oolite” and the “
Caninia
Oolite”, belong to neither of those zonal limestones. The succession consists of two major rock groups : an Oolite Group of Zaphrentidan age below, and a Calcite-Mudstone Group of Upper-Caninian age above. The Lower
Caninia
Zone is not represented.

The Oolite Group is in primary lithology a generally uniform series of almost quartz-free, light-grey, massive crinoidal oolites resting directly on the Lower Limestone Shales. At the plane of the sub-Viséan unconformity it thins rapidly westwards through overstep by the Calcite-Mudstone Group.
Most of the beds of the Calcite-Mudstone Group are quartz-rich finely fragmental algal and foraminiferal limestones, pellet-rocks, and calcite-mudstones. Apart from a prominent band of gritty oolite they consist mainly of organic detritus, the finest grades probably being algal muds.

Variations in thickness of the Calcite-Mudstone Group, especially notable in the neighbourhood of the Vale of Neath disturbance, are partly internal, but arise mainly because of Seminulan overstep. The greater part of the Upper
Caninia
Zone is everywhere missing. The Calcite-Mudstone Group is completely transgressed in
The Lower Carboniferous Stratigraphy of the Omagh Syncline, Northern Ireland
Authors: Simpson Ian Morven 
Published: October 2009

Summary

The Omagh syncline is a large outlier of Lower Carboniferous rocks in Counties Tyrone and Fermanagh, Northern Ireland. The succession, about 8000 feet thick, is divisible into four lithologically distinct groups. At the base, resting unconformably on Dalradian rocks, is the Omagh Sandstone, a group of siliceous sandstones and conglomerates. It is confined to the eastern half of the outlier and its zonal position is indeterminable. The Claragh Sandstone which follows is characterized by abundantly felspathic sandstones. It overlaps the Omagh Sandstone in the west and rests on Dalradian and Moinian rocks. The fauna suggests a C
1
age.

The third group, the Pettigo Limestone, is dominantly calcareous with a rich fauna indicating a C
2
S
1
age. The Clonelly Sandstone Group at the top of the succession, though mainly arenaceous, is more variable in lithology than the preceding groups. It is referred to the S
2
Subzone.

The gentle folding of the Lower Carboniferous along an E.-W. axis is ascribed to Armorican compression, as is the development of four major faults by lateral slipping along NE.-SW. fault-planes.
The source rocks of the Lower Carboniferous clastic sediments were the Moine and Dalradian rocks of the west and north. Virtually all the sediments were deposited in a marine environment.
I. Introduction
In North-West Ireland several extensive outliers of Lower Carboniferous rocks rest unconformably on an irregularly eroded surface of Dalradian and Moinian metamorphic rocks (Fig. 1). The outliers are the remnants of a once widespread covering of sedimentary rocks. One of the largest of the
Analysis of Minor Structures Near Ardmore, County Waterford, Eire
Authors: Dawson-Grove Glascott Eyre 
Published: October 2009

Summary
Geologically, the Ardmore area consists of Upper Devonian and Lower Carboniferous rocks lying in E.—W. folds which are transected by N.—S. faults.
The orientations of all planar features were measured in localities chosen for detailed examination. The joints, veins and shear-planes were plotted stereo-graphically, and, from the resulting contour diagrams, structural maps were prepared.
It has been established that the area has suffered three main phases of deformation—N.—S. compression, E.—W. tension, and clockwise shear, probably in that order. Deductions are drawn on the interrelation of the fracture-planes exemplified by the cleavage, joints, faults and other manifestations of crustal deformation.
The Lithology and Structure of a Boulder-Bed in the Dalradian of Mayo, Ireland
Authors: Elwell Royston William Dunlop 
Published: October 2009

Summary
Exposures of a boulder-bed resembling those of Donegal have been found in North-West Mayo. The boulders are granitic in aspect, though severely affected by cataclasis, and the matrix is foliated and generally semi-pelitic. The probable succession in North-West Mayo and the position of the boulder-bed in it have been determined, but no correlation with other areas has yet been established.
For the most part the boulders are about equidimensional, but locally they are intensely deformed. Many of the deformed boulders are markedly elongated and flattened. The elongation is parallel to the regional lineation, which generally plunges to the south-east.

Although several analyses of pebble deformation in other areas are interpreted as indicating a main movement parallel to the elongation, it is considered that the Mayo boulders have been rolled and thus extended in
b
. This conclusion is strongly suggested by more than one line of evidence. Firstly, certain mullion structures (with a south-easterly plunge corresponding to the direction of boulder elongation) were found to have their peripheries determined by complex folds that have required considerable movement at right angles to the mullion trend. Secondly, mapping in North-West Mayo has revealed large-scale folding that plunges to the south-east. Thirdly, the shapes of many of the deformed boulders are not such as would be expected if they had been extended in
a
, though they might well have been produced by rolling and flattening.

Petrofabric investigations have been carried out on some of the boulders, and the relationship between fabric orientation and deformation is briefly discussed in the paper.
The Conodont Fauna of the Keisley Limestone
Authors: Rhodes Frank Harold Trevor 
Published: October 2009

Summary

Conodonts are comparatively rare in the Keisley Limestone, but the fauna includes a variety of forms, comprising 17 genera. Three of these genera,
Keislognathus
,
Rosagnathus
and
Strachanognathus
are new, and five new species are also described. The fauna is compared with others of a similar age, and the ranges and stratigraphical value of the conodont genera are considered.
An Appinitic Facies Associated with Certain Granites in Jersey, Channel Islands
Authors: Wells Alfred Kingsley , Bishop Arthur Clive 
Published: October 2009

Summary
The rocks here referred to as appinites form part of the essentially dioritic facies marginal to both the north-western and south-eastern complexes in Jersey. Mineralogically they are characterized by abundant long prismatic amphiboles, rich in titanium. Many of these contain cores of mica or felsic material, the nature and origin of which are discussed.
The country rock commonly occurring in association with the appinitic rocks is dioritic in both complexes; and at Ronez in the north of the island it contains relicts which prove it to be, at least in part, metasomatized gabbro. The diorites and appinites both consist of essentially the same mineral assemblage and, whilst the latter are not metasomatic in the generally accepted sense of the word, there is no doubt that a large proportion of their substance has been derived from gabbro by way of a series of changes initiated by the nearby granites. The changes by which gabbroic material was converted into dioritic have been continued and accentuated, presumably by emanations from the granite, with the local building up of strong flux concentrations, which led to the formation of " pockets " consisting of crystal mush with interstitial liquid. It was from this " magma " that the appinitic rocks crystallized, under essentially pegmatitic conditions. It was demonstrably mobile, and a turbulent fluxional structure is highly characteristic.
Textural interpretation receives critical attention in the paper, particularly in so far as it concerns replacement phenomena. The observed changes in mineral contents are consistent with crystallization from a magma, and follow the lines of Bowen's discontinuous reaction series, which must be extended at the low temperature end to include phases usually regarded as secondary, but here unquestionably primary.
An unusual feature, occasioned by the special environmental conditions, has been the growth of amphibole and apatite crystals of a hollow-shell type, in which crystallization starts on the outside and progresses towards the centre.
In the sequence of paramorphic changes, the inheritance by a later phase of the internal structure of the earlier one which it is replacing, in accordance with the principle of least disturbance of the original Si-0 lattice, is strikingly displayed in these rocks.
Problems of classification and nomenclature are involved and receive due attention in the paper.
The Silurian Rocks of the Talerddig District, Montgomeryshire
Authors: Bassett Douglas Anthony 
Published: October 2009

Summary
The paper deals with the ground between Dinas Mawddwy (Pugh 1928) and Tarannon (Wood 1906). The rocks of the area are grits, siltstones, shales and mudstones forming part of a greywacke suite. They are subdivided into the Gelli, Talerddig and Dolgau groups (Upper Valentian) and the Denbighshire Group (Lower Wenlockian).
Some of the beds, for example the blue shales in the Dolgau sequence, are remarkably constant throughout the area, but in general, beds, members and groups exhibit pronounced variation in thickness and, to a lesser extent, in lithology. There is a general thinning eastward and southward, the latter being contrary to the regional attenuation towards the geosynclinal axis.
The rocks are folded into a series of major and minor folds associated with which there is well-developed cleavage and jointing but little faulting. Three fold-sets are distinguished : a predominant NNE.-SSW. set, a less-pronounced E.-W. and an insignificant NW.-SE. set. The area is, therefore, dominated by the NNE.-SSW. structures prevalent in the Harlech, Plynlimon and Van domes to the west and south, but also contains some E.-W. structures related to the Berwyn dome to the north-east.
The Geological Evolution of Wales and the Adjacent Regions
Authors: Jones Owen Thomas 
Published: October 2009

Summary
The thicknesses of the Lower Palaeozoic rocks in the region are represented by isopachytes, and by summation isopachytes are constructed for the Cambrian, Ordovician and Silurian systems, as well as for the Lower Palaeozoic. In the centre of the geosyncline the rocks may have reached a thickness of nearly 40,000 feet and the slope at the base of the Palaeozoic on its eastern flank was about 16°. The average rate of accumulation of the sediments is estimated for each system.
Earth-movements which preceded the deposition of the Old Red Sandstone affected an area extending for some miles on each side of the Irish Sea. Within this area the Old Red Sandstone rests unconformably on all earlier formations, but to the eastward it follows conformably on Silurian rocks.
Evidence is adduced that the so-called Caledonian movements which folded the Lower Palaeozoic rocks of Wales occurred after the deposition of the Lower Old Red Sandstone, and, further, that the formation probably attained a thickness of many thousands of feet over large areas in Wales and in England where it no longer occurs.
It is inferred that the sediments were derived largely from the products of tropical or sub-tropical weathering and that they were mainly products of river action. The Upper Palaeozoic is estimated to have attained a thickness in South Wales of 20,000 to 24,000 feet.
The effects of post-Carboniferous movements and the subsequent history of the area are briefly reviewed.
Pediplanation and Isostasy: An Example from South Africa
Authors: King Lester C. 
Published: October 2009

Summary
An outline is given of late Mesozoic and Tertiary erosional and depositional cycles in South Africa. The elevations of these surfaces are compared with elevations calculated, allowing for isostatic recovery between successive cycles of erosion. Concurrence between the two sets of elevations is noteworthy. Isostatic recovery thus seems to occur as a simple function of erosion and deposition under the pediplanation principle.
A geophysical study of the granite problem
Authors: Bott Martin Harold Phillips 
Published: October 2009

Summary
Following an introductory account of granite petrography, hypotheses for source and emplacement of granite are classified in a form suitable for geophysical assessment. The evidence of the negative gravity anomalies associated with post-tectonic granites is summarized and considered in its various aspects of space, mass and density. For comparison with observations, gravity fields are calculated for the types of mass distribution expected for the various hypotheses. The seismological evidence of Gutenberg's low-velocity lithosphere channel is also considered.
The gravity results indicate that batholiths have considerable extent in depth and hence forcible intrusion is unlikely to be the main mechanism in post-tectonic granite emplacement. The negative anomalies demonstrate that the emplacement involves a considerable over-all removal of mass from the regions now occupied by the granite, but there is no support from the gravity anomalies for the hypothesis that the bulk of this now resides in the country rocks as a basic front. The evidence suggests that both downward diffusion of surplus mass and stoping are possible primary mechanisms. Geophysical, geochemical and geological observations conspire to support the idea that a true granitic layer, underlying the metasedimentary rocks, provides the source material for granite.
Syn- and post-emplacement uplift of granite batholiths and the origin of mantled gneiss domes are attributed to isostatic-type phenomena depending on the granite mass deficiency.
The glaciations of East Anglia and the East Midlands: a differentiation based on stone-orientation measurements of the tills
Authors: West Richard Gilbert , Donner Joakim Jalmar 
Published: October 2009

Summary
Measurements of the long-axis orientation of stones in Older Drift tills of East Anglia and the East Midlands have been made to determine the direction of ice movement. The directions of preferred orientation of the long axes of the stones, together with the stratigraphical evidence of certain of the tills measured, give a pattern of direction and stratigraphy in which three successive episodes of ice advance may be distinguished. These are named the Cromer, Lowestoft and Gipping advances. The Cromer Advance deposited the North Sea Drift, the Lowestoft Advance Pennine Drift in the East Midlands and chalky boulder-clay (including Baden-Powell's Lowestoft Boulder-clay) in East Anglia, and the Gipping Advance chalky boulder-clay (including Baden-Powell's Gipping Boulder-clay) both in the East Midlands and East Anglia. Measurements of the long-axis orientation of stones in Older Drift tills of East Anglia and the East Midlands have been made to determine the direction of ice movement. The directions of preferred orientation of the long axes of the stones, together with the stratigraphical evidence of certain of the tills measured, give a pattern of direction and stratigraphy in which three successive episodes of ice advance may be distinguished. These are named the Cromer, Lowestoft and Gipping advances. The Cromer Advance deposited the North Sea Drift, the Lowestoft Advance Pennine Drift in the East Midlands and chalky boulder-clay (including Baden-Powell's Lowestoft Boulder-clay) in East Anglia, and the Gipping Advance chalky boulder-clay (including Baden-Powell's Gipping Boulder-clay) both in the East Midlands and East Anglia.
The presence of interglacial deposits below the till of the Cromer Advance (Cromer Forest Bed Series), and between the tills of the Lowestoft and Gipping advances (Hoxne Interglacial) makes it possible (a) to recognize two glaciations, the first including the Cromer and Lowestoft advances, the second the Gipping Advance, and (b) to correlate the two glaciations respectively with the Elster and Saale glaciations of North-West Europe. The Lowestoft and Gipping glaciations as now defined correspond with those so-named by Baden-Powell except that the Lowestoft Glaciation is taken to include the Cromer Advance.
A Late-glacial deposit at St. Bees, Cumberland
Authors: Walker Donald , Godwin Harry 
Published: October 2009

Summary
Peat and mud beds lying in the Middle Sands at St. Bees have been reinvestigated. The peat which was described underlying the Scottish Readvance boulder-clay has been eroded away. None of the three remaining organic layers within the Middle Sands is of interglacial age. Pollen analysis has shown two of them to be Post-glacial and one Late-glacial. The latter covers a complete interstadial period, probably, but not certainly, the Allerød.
The Buchan anticline of the Banff nappe of Dalradian rocks in North-East Scotland
Authors: Read Herbert Harold , Farquhar Oswald Cornell 
Published: October 2009

Summary
The Dalradian rocks involved in the Buchan anticline in Aberdeenshire belong to four groups: (1) the Ellon Gneisses, in part migmatitic, equated with the Ben Lui-Ben Lawers groups of the standard Lower Dalradian of Perthshire, (2) the Mormond Hill Quartzite, placed in the Upper Dalradian, and conformably followed eastwards by (3) the Collieston Beds of greywacke facies, and lastly, (4) the Fraserburgh Beds of similar facies occurring west of the Mormond Hill Quartzite, from which they are separated by a dislocation.
The Buchan anticline is a structure imposed on the great recumbent fold of the Banff nappe, this being made of a migmatitic core of the Lower Dalradian Ellon Gneisses, separated from the Upper Dalradian by a dislocation, the Boyne lag. The anticline is considered to result from the eastward and upward movement of the migmatized core of the great fold. As a consequence, the Collieston Beds are piled up to the east in front of the brow in a gigantic stack of small recumbent folds. West of the tectonic aggregation of Mormond Hill Quartzite which caps the Ellon Gneiss anticline, the Fraseburgh Beds have slid down a gentler tectonic slope into the Turriff syncline—they are characterized by broad, gentle, synclinal portions and narrow, steeply overtuned, anticlinal portions. These cover movements are considered to be activated by a bulging upwards deep down in the migmatitic core of the Banff nappe; the Collieston and Fraserburgh Beds are shed off on the two sides of the maximum rise.
As the movements ended, an essentially thermal metamorphism, effected by heat-conduction from the migmatite core and characterized by regional andalusite and cordierite, was overprinted on the folded cover. The metamorphic zones form a metamorphic "anticline" two miles west of the tectonic anticline. In the centre of this metamorphic "anticline", the migmatite front has risen highest into the cover folds.
The geographical distribution of brachiopods in the British Middle Lias
Authors: Ager Derek Victor 
Published: October 2009

Summary

A study of the rhynchonelloid and terebratuloid faunas of the zone of
Pleuroceras spinaturn
in the Lower Jurassic of the British Isles has revealed a pronounced lateral variation in the distribution of genera and species. Four distinct faunal provinces are distinguished within the British area, and two of these are subdivided into two and three subprovinces respectively. The palaeo-ecological and palaeogeographical implications of the distribution are discussed.

The Mendip, Moreton in Marsh and Market Weighton axes are shown to have acted as faunal barriers in
spinatum
Zone times. The ironstone facies of the Midlands provided a strongly selective environment. There are marked affinities between the brachiopod fauna of South-West England and that of Normandy, and also between those of Yorkshire and western Germany. The Hebridean region is believed to have been populated by migratory streams from both the above faunas, together with a third stream coming presumably from the north. A strong and ,effective faunal barrier existed along the line of the Pennines, possibly connecting with the Moreton in Marsh axis.

Certain forms are thought to have been restricted to particular areas throughout considerable spans of Jurassic time.
The Criffell-Dalbeattie granodiorite complex
Authors: Phillips William John 
Published: October 2009

Summary
The Criffell-Dalbeattie granodiorite complex is composed of three granodiorie' and associated quartz-dioritic rocks. Four-fifths of the area of exposed “ granitic ” rocks is occupied by the main Criffell-Dalbeattie granodiorite and the greater part of the paper is devoted to a study of the petrology, structure and emplacement of this granodiorite pluton. It is concluded that the main granodiorite was emplaced as a magma by the forceful displacement and some assimilation of the country rooks.
The western end of the complex is considered in relation to the main pluton. The her-grained intermediate granodiorite was emplaced before the main pluton and itself intrudes the Bengairn quartz-diorite which flanks its north and west' margins. The Bengairn quartz-dioritic rocks are considered to have developed by the metasomatic transformation and mobilization of permeated hornfelsic material. It is suggested that the intermediate granodiorite magma may represent the h a 1 result of the metasomatic transformation of the country rooks, and it is postulated that a relatively small movement and internal circulation of the mobilized permeated material would be sufficient to give the essentially magmatic features exhibited by the intermediate granodiorite. The close association of the intermediate granodiorite with the Bengairn quartz-dioritio rocks may well be an indication of the possible origin of the granodioritic magmaa by the “ magmatization ” of permeated hornfelees in regions not much lower than the one now exposed in this area.
The more basic composition of the later main granodiorite is attributed to the effect of the assimilation it accomplished during its longer and more active life as a magma. The porphyrite-porphyry minor intrusions and the fine-grained granodiorite may be related to various stages in the crystallization of the granodiorite magma which finally consolidated as the central porphyritic granodiorite.