bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional distribution and thickness of post-Palaeozoic sediments on the continental margin of southern Africa
Authors: Dingle R. V.
Published: May 2009

The asymmetry of the continental margin around southern Africa can be related to Mesozoic sediment thicknesses, which were in turn controlled by the local structural setting. On the west coast, the Orange Basin sediments were built out as a thick wedge over the margin of the continent by discharge from the Orange River, whereas on the Agulhas Bank, sedimentation was confined to continental areas. Off the east coast the extremely narrow margin of the continent did not form an effective trap for sediments, which were readily carried beyond it. Cainozoic sediments are thin, and modify the Mesozoic sediment pile only locally on the outer shelf and slope.
Uralites and uralitization in the ultramafic belt of southern New Caledonia
Authors: Rodgers K. A.
Published: May 2009

Chemical examination of uralites and their parent pyroxenes from associated eucrites and bronzitites indicate that the alteration can proceed by diverse paths and yield differing actinolites. Alteration in eucrites can be interpreted as occurring in a near closed system but in the bronzitites an external source of Ca and Al is required.
The origin of kink bands near Tintagel, North Cornwall
Authors: Hobson D. M.
Published: May 2009

Near Tintagel, southerly verging kink bands cut flat-lying Upper Palaeozoic Plates and schists. The bands are about 2 cm wide and most of them terminate by a Decrease of amplitude but not wavelength. The length of the kinked limb and the frequency of the bands were probably determined by lithology when the deformation began, The bands may have formed under a N-S directed maximum principal stress which was Slightly oblique to the layering.
Sedimentary facies of the Forest Marble (Bathonian), Shipton-on-Cherwell Quarry, Oxfordshire
Authors: Allen J. R. L. , Kaye P.
Published: May 2009

The unrivalled exposures of the quarry show the Forest Marble to comprise a complex association of vertically and laterally changing facies. These are interpreted to represent environments ranging from subtidal-intertidal fully marine sand shoals and hard substrates colonized by corals, to mud flats and tidal channels associated with coastal swamps. An earlier interpretation of calcarenites in the Forest Marble is inapplicable at Shipton-on-Cherwell.
The form of the Beinn an Dubhaich granite, Skye, Scotland
Authors: Raybould J. G.
Published: May 2009

The Beinn an Dubhaich granite has previously been interpreted as a boss, and as a sheet intrusion. The present paper suggests that the structure of the granite is more complex than either of these interpretations implies, and the form is probably that of a shallow funnel intrusion.
The Lewisian Geology of the Little Sand Dioritic Mass, Gairloch
Authors: Bhattacharjee C. C.
Published: May 2009

A study of the geological history of a small dioritic mass near Gairloch has revealed the presence of rock types and structural elements not represented in most of the Lewisian of the district. Coarse grained diorite, showing intrusive relations to granulitic rocks of possible sedimentary derivation, has been foliated and subsequently intruded by microdiorite during pre-Laxfordian episodes. The Little Sand mass has subsequently been involved, probably as a thrust slice of basement, in the sequence of Laxfordian (about 1,500 m.y.) structural and metamorphic episodes which affected the more common Lewisian metasediments and metabasites.
Notes on some Ferruginous Strata in Buckinghamshire and Wiltshire
Authors: Casey R. , Bristow C. R.
Published: May 2009

The name Whitchurch Sands is proposed for patches of ferruginous strata scattered for 75 miles along the western edge of the Cretaceous from Stewkley, Buckinghamshire, to the Vale of Pewsey, in Wiltshire. They are interpreted as the vestiges of a marine-brackish formation of Middle Purbeck age indicating the transgressive front of an advancing sea thought to have come from the north and which left its mark farther south in the Cinder Bed of Dorset. In the past they have been regarded as Lower Greensand, Wealden, or Portland Sand. In places, e.g. Quainton, Buckinghamshire, they are overlain by undoubted Lower Greensand (Seend Ironsand) of Upper Aptian date. Both in faunal characters and in stratigraphical relations the Whitchurch Sands have much in common with the Serpulite of Hanover and the basal “Wealden” of the Bas Boulonnais.
Age Relations of Lewisian Basic Rocks, South of Gairloch, Ross-shire
Authors: Bowes D. R. , Ghaly Tharwat S.
Published: May 2009

During the Laxfordian orogenic period dolerite intrusions crosscut and were chilled against vertical bands of hornblende schist that trend N.W.–S.E. Subsequent metamorphism affected both the regional hornblende schists and the dolerites, and narrow bands of hornblende schist were formed in places at the expense of doleritic chilled margins. Previous interpretations of Lewisian geochronology, tectonics and metamorphic history made on the basis of a unique pre-Laxfordian basic dyke phase, cannot be applied to the rocks south of Gairloch.
Joint Patterns at Dalrymple Hill, North-east Tasmania
Authors: Williams Emyr
Published: May 2009

Patterns of joints in flat-lying Permian rocks have been compared with those of folded Mathinna beds, of Siluro-Devonian age, across an exposed unconformity, and with those of a nearby Late Devonian granite. The patterns of the Permian rocks and the granite are similar, and each joint set appears to be related to parallel-trending post-Permian faults in the region. However, there is no representation of the joint sets of the Permian rocks in the Mathinna beds, considered to be due to shear failure either along bedding up to 18 degrees from the expected position, or along pre-existing open joints up to 65 degrees away. Lack of apparent order in the deflection and termination of joints against one another in the Mathinna beds indicates contemporaneity of formation of the open continuous fractures of differing attitudes, suggesting that the initial form of joints is as minor discontinuous cracks, which later develop into the open joints examined in surface outcrops.
The Trilobite Anacheirurus frederici (Salter) from the Tremadoc Series of North Wales
Authors: Whittard W. F. , Dean W. T.
Published: May 2009

Cheirurus (Eccoptochile) Frederici Salter, 1864, the type species of Anacheirurus is redescribed. It is considered to be synonymous with Lehua, thus extending the stratigraphical range of Anacheirurus upwards to the Llanvirn, or perhaps Llandeilo, Series.
The Lower Carboniferous Limestone Knolls of Clitheroe, Lancashire
Authors: Parkinson Donald
Published: May 2009

The problem of the genesis of these biohermal structures is re-examined to test the hypothesis that they are bank sediments and not knoll-reefs. The study is based largely on the field work of the Geological Survey (Earp et al., 1961). It is argued that depositional dips have not been increased by differential compaction and it is demonstrated, by elimination of the tectonic component of the existing divergent dips, that original dips locally exceeded 60 degrees. It follows that the knolls possessed some rigidity of frame and the term “reef” seems appropriate. It is argued that the Worsaw and Twiston knolls rose upwards of 600 feet above the surrounding muds.

The conclusions of the Clitheroe Memoir that certain beds of the Worston Shale Group formerly thought to post-date the knoll limestone are in fact of the same age is accepted, but it is argued that these sediments, which are not differentiated from other deposits by the Survey officers, follow a non-sequence.
A Note on Costellae in Orthid and Strophomenid Brachiopods
Authors: Kemežys K. J.
Published: May 2009

The costellae of a population of brachiopods can be quantitatively described by plotting the total number of costellae on a valve against the length of its margin. The resultant curve describes the continuous change of the average distance between adjacent costellae during growth. When costellae first appear, this distance has the value of about 0·06 mm and it increases during growth to various degrees in different brachiopod species.

If it is assumed that costellae mark the sites of setae, then the magnitude of the distance between adjacent costellae can be discussed in terms of the function of setae.

The magnitude of the parameters of the distribution of setae and punctae are compared to the silt/sand dividing line.
Osculocystis, a New British Silurian Cystoid
Authors: Paul C. R. C.
Published: May 2009

Osculocystis, a new scoliocystine cystoid, is characterized by reduced oral plates which form a tubercle; three pectinirhombs, B2: IL2, L2: R1, and L4: R4; and apparently only one brachiole. Osculocystis is based on a single specimen of the type species, O. monobrachiolata, from the Lower Silurian of Buildwas, Shropshire. It is the first recorded Lower Silurian cystoid from Britain and is most closely related to Glansicystis Paul.
The Alkaline Centre of Yelele and its Bearing on the Petrogenesis of other Eastern Uganda Volcanoes
Authors: Nixon P. H. , Clark L.
Published: May 2009

An account is given of Yelele, a Miocene volcano, situated on the Turkana escarpment, north-east Uganda. It is composed of lavas and dykes of nephelinite, phonolite, tephrite, and trachyte together with olivine-bearing varieties, and has a central plug of ijolite and nepheline syenite.

The lavas are described and compared with those of other eastern Uganda centres and the petrogenesis discussed in the light of experimental data from the Geophysical Laboratory of the Carnegie Institution of Washington.

A northern (Yelele) plagioclase-bearing suite of lavas and a southern (Elgon) melilite-bearing suite are derived by different fractionation trends from an olivine melanephelinite parent which itself is the dense portion of a nephelinitic parent magma.
Ordovician Conulariids from the Bosphorus Area, Turkey
Authors: Sayar C.
Published: May 2009

Four species of Exoconularia, including E. istanbulensis, sp. nov., and one Archaeoconularia, are recorded from beds hitherto regarded as Silurian, but which are now shown to be of Middle Ordovician age. A revised stratigraphical succession is proposed.
The Luxembourg Colloquium and the Revision of the Stages of the Jurassic System
Authors: Lloyd A. J.
Published: May 2009

A report is given of the origin, aims, proceedings, and conclusions of the “Colloquium on the Jurassic” held in Luxembourg, August, 1962. The English version of its recommendations to the International Geological Congress are quoted in full; the effects of their adoption on current English usage are discussed and some critical opinions on the report of the International Sub-Commission on Stratigraphical Terminology are expressed.
The Petrogenesis of Hornblende-mica-lamprophyre Dykes at South Hill, Jersey, C. I.
Authors: Bishop A. C.
Published: May 2009

At South Hill, 1/2 mile south-east of St. Helier, two hornblende-mica-lamprophyre dykes cut the Fort Regent granophyre. They are themselves displaced by two gently dipping shear zones and a dolerite dyke belonging to the main Jersey dyke swarm cuts the granophyre, lamprophyres, and shears, Petrographically the lamprophyres are of the spessartite-kersantite type, but the presence of euhedral brown amphibole invites comparison with the camptonites. The genesis of the lamprophyres is discussed and a significant role is assigned to volatile constituents.
The Early Development of Gryphaea
Authors: Swinnerton H. H.
Published: May 2009

The material for this work came from an extensive temporary exposure in the Vale of Belvoir (South Notts) which cut across the outcrops of some 70 feet of Lower Liassic Beds. Approximately one–third of the Gryphaea shells carried developmental stages. The youngest of these consisted of larval shells closely resembling those of the modern Ostrea. During the breeding season larvae settled at least twice. The growth of spat is described. The great majority of these died in early life and relatively few grew to later stages. About 5 per cent broke loose. Many of the host shells started life attached to small shells or fragments. A study of life conditions throws light on the course of deposition in Liassic waters.
Tectonic Slides
Authors: Fleuty M. J.
Published: May 2009

The usefulness of the term slide for a fault formed in close connection with folding is discussed, and a definition suggested.
Some Structures in the Dalradian Pillow Lavas of the Tayvallich Peninsula, Argyll
Authors: Wood Dennis S.
Published: May 2009

Pillows are described in various stages of production from small parent lava flows. The lavas flowed into water–laden sediments down to depths at which the latter were capable of supporting the weight of lava. Because of their lack of systematic relationship to tectonic axes, certain structures observed in these sediments are interpreted as pushing folds induced by the “intrusion” of lava flows. The direction of flow of the lavas was towards the north.
A Re-Interpretation of the Ben Lui Fold
Authors: Roberts John L. , Treagus J. E.
Published: May 2009

A re-interpretation of the Ben Lui Fold (and its equivalents) is suggested on the basis of correlating the structures in the South-West Highlands (Roberts, 1963) with those in Upper Glen Lyon (Treagus, in preparation) and the Tummel (Sturt, 1961) and Blair Atholl (Harris, 1963) districts. In all these districts the Cowal-Loch Tay flat belt and the steep belt to its north-west define a structure previously interpreted as the hinge of the primary and recumbent Ben Lui Syncline. As primary structures are themselves folded round this hinge, and as minor secondary structures are congruent with it, the authors interpret the Ben Lui Fold as a secondary structure.
Cross-bedding in the Millstone Grit of the central Pennines and its Significance
Authors: Wright M. D.
Published: May 2009

Most of the cross-bedding in the Central Pennine Millstone Grit occurs in the coarse sandstones and indicates that they are probably fluvial in origin. The cross-bedding often occurs within sheets of sandstone, and it is suggested that each sheet was deposited during one episode of flooding. Medium-grained arenaceous rocks show other varieties of cross-bedding that could have been formed on tidal flats, but this evidence is inconclusive.
Observations on the Nepheline Syenites of Koraput, Orissa
Authors: Bose M. K.
Published: May 2009

The nepheline syenites of Koraput, Orissa, in eastern India, are described for the first time with mineralogical details. The major rock type is a hypersolvus nepheline syenite. The mafic minerals are iron-rich biotite and subordinate alkali ferrohastingsite, the latter coexisting with titanomagnetite. The crystallization history of the magma has been interpreted in the light of chemical data on the rock and coexisting nepheline and alkali feldspar.
The Association of Amphibolite and Albitite, Kragerø, South Norway
Authors: Elliott R. B.
Published: May 2009

In the Kongsberg-Bamble series of South Norway leucocratic albitites are associated with amphibolites. The plagioclase of the albitites is An2-An13, that of the amphibolites is commonly An28-An40. The metamorphic facies is upper almandine amphibolite and the inferred P. T. conditions are about 700° C. and 7,000 to 8,000 bars. Recent experimental work indicates that at these temperatures and pressures amphibolites will begin to melt and the first liquid will be of albitic composition. It is suggested that the albitites owe their origin to the partial fusion of their enclosing amphibolites.
An Association of Rhyolite and Ignimbrite in the Kilchrist Vent, Skye
Authors: Ray Prem S.
Published: May 2009

A small mass consisting of three intrusions of fine-textured acid rocks occurs within the basaltic agglomerates of the Kilchrist Vent of Tertiary age. One of the intrusions comprises flow-layered rhyolite and ignimbrite. It is thought that the rock-types represent two distinctive eruptive waves. A form of ovoidal structure not seen elsewhere in the Kilchrist area occurs in another rhyolite intrusion.
An Analysis of the Deformation in a Fold in North-east Tasmania
Authors: Williams Emyr
Published: May 2009

Microscope studies of a flattened fold are consistent with conclusions from macroscopic observations that whereas mudstone cleavage development may have resulted from a laminar-type flow governed by competent confining sandstone beds, the sandstone cleavage appears to be related to the dilation of texture during the early stages of deformation. Continued deformation results in a textural disruption of the initially competent sandstone, which is considered to allow flattening.
Crystal Size Frequency Distribution of Garnets in Some Analysed Metamorphic Rocks from Mallaig, Inverness, Scotland
Authors: Galwey A. K. , Jones K. A.
Published: May 2009

In an attempt to obtain information about garnet nucleation a series of eleven apparently homogeneous metamorphic rocks, from a small area near Mallaig, Inverness, Scotland, have been analysed to determine bulk chemical and modal compositions, garnet grain size and number of garnet crystals occurring in unit volume of rock (N). No correlation of N with any function of chemical and modal compositions could be found, and it is therefore concluded that, if the influence of trace components can be neglected, externally imposed factors (for example, time-temperature variation) or internal physical factors (for example, the surface area of the rock just prior to garnet formation) must exert a controlling influence on garnet nucleation. It was found, however, that in each specimen, there was a preferred crystal radius and the relative frequency of occurrence about this preferred value was constant for all samples studied. Preliminary comparison with other systems, investigated by the authors, suggested that the nature of this relationship may provide evidence of the conditions under which these rocks recrystallized.
Combined Palaeomagnetic and Petrological Delineation of Faults in Miocene Basalts of Oregon
Authors: Watkins N. D. , Larson E. E.
Published: May 2009

Distinct variations of the natural remanent magnetism in a section of volcanic rocks in Greaser Canyon, Lake County, Oregon, correlate with faulting inferred independently. The palaeomagnetic data is also consistent with the occurrence of a suspected diastem in the local volcanic sequence.
The ‘Precambrian’ in Cambria
Authors: Challinor J.
Published: May 2009

The history of investigation of the rocks at present classed as Precambrian in the type region of the Cambrian system in the north-west corner of wales (Cambria), where that system was first named and its lower limit locally defined, is reviewed. The Arvonian volcanic series was originally included in the Cambrian System, the Monian metamorphic group remaining as Precambrian.
A classification diagram for fold orientations
Authors: Rickard M. J.
Published: May 2009

A new structural diagram is proposed that allows simple precise classification of fold orientations. The diagram is also useful for the analysis of the relationship between fold style and orientation.
Tectonic transpression in Caledonian Spitsbergen
Authors: Harland W. B.
Published: May 2009

In addition to the well-established extension, compression and transcurrent relative movements between plates of the lithosphere, this paper considers intermediate or oblique relative movements, namely, transtension and transpression. Transtension is already well established in oblique zones of ocean spreading which consist of stepped transform faults. Transpression is a more complex process. The tectonic consequences of a transpression model are outlined and it is suggested that the tectonic style in Caledonian Spitsbergen provides evidence for this transpression regime as an intermediate stage between compression and transcurrence. It is also suggested that transpression should occur generally and may relate the development of transcurrent faults in orogenic belts.
Palaeozoic glacial rocks recently discovered in northern Ethiopia
Authors: Dow D. B. , Beyth M. , Hailu Tsegaye
Published: May 2009

Tillite and other glacial rocks have been found at the base of a sedimentary sequence in the northern part of Tigre Province, Ethiopia. Their glacial origin cannot be doubted, for in addition to beds of tillite containing abundant striated boulders, glaciated bedrock has been found.
The rocks are correlatives either of the Upper Carboniferous glacial rocks of southern Africa or of Ordovician glacial rocks recently mapped in the Hoggar District of southern Algeria.
Alpine serpentinites, oceanic ridges, and continental drift
Authors: North F. K.
Published: May 2009

It is suggested that Alpine serpentinites are not a characteristic of eugeo-synclinal mountain development, but represent a special case in which the leading edge of a drifting continental mass overrode an oceanic ridge. Serpentinites younger than Caledonian are overwhelmingly of Mesozoic age, and essentially contemporaneous with the latest principal episode of continental drift. Furthermore, they occupy the leading edges of continental blocks which must have been moving during that episode.

Older serpentinite belts of comparable proportions may reflect geosynclinal seaways originally wide enough to accommodate oceanic ridges. The Baltic-Breton and Siberian continents must in that case have drifted westward (with respect to their present alignments) in early Caledonian time, and Australia eastward in early Hercynian. The principal episode of Mesozoic drift is thought to have occurred during Triassic and Jurassic times, and not during Jurassic and Cretaceous.
An alternative to the ‘clastic trap’ interpretation of oolitic ironstone facies
Authors: Brookfield M.
Published: May 2009

The rarity or absence of clastic grains in oolitic ironstones is often explained by the hypothesis of a ‘clastic trap’ in which the clastic grains are deposited before reaching the zone of iron oolith formation. If the hydrodynamic behaviour of the iron ooliths and clastic grains is considered, this is unnecessary. The two components are spatially separated due to their different densities and different behaviour, depending on whether they are in suspension or saltating, or rolling. Iron ooliths can be rolled more easily than the equivalent clastic grain size, whereas clastic grains are more easily saltated or moved in suspension than the equivalent size of iron oolith. These differences cause spatial separation of the two facies.
Problematical Microfossils from the Gault Clay
Authors: Black Maurice
Published: May 2009

Four species of calcareous microfossils whose systematic position is unknown occur in very small numbers in the English Gault (Middle and Upper Albian). They are associated with much more abundant coccoliths, and are believed to be the hard parts of planktonic organisms whose possible relationships are discussed, but cannot at present be determined.
The Pre-Cambrian rocks of the N.E. Ox Mountains, Eire
Authors: Lemon G. G.
Published: May 2009

Moinian and Dalradian metamorphic rocks occur in the north-east extension of the Ox Mountains. The petrology and migmatization of the Moinian are discussed and Dalradian rocks are described for the first time from this area. Reference is made to the structure and brief comparisons are made with adjacent areas. The status of the so-called ‘eclogites’ in the Moinian is also discussed.
Coexisting chloritoid and staurolite and the staurolite–chlorite isograd from the Agnew Lake area, Ontario, Canada
Authors: Fox J. S.
Published: May 2009

Chloritoid and staurolite bearing rocks from the Agnew Lake area in northern Ontario were studied petrographically and with the electron microprobe. A staurolite–chlorite isograd is postulated, above which chloritoid and staurolite coexist in equilibrium, and a Schreinemakers-type petrogenetic grid is constructed to illustrate how the isograd might fit into a paragenetic sequence.

The staurolites from the area are observed to be more ‘siderophile’ than the chloritoids and this suggests that the chlorite participating in the isograd reaction is prograde. This is confirmed in the ‘real’ isograd reaction:

1.559ctd+5.000and+0.009rut+0.058ilm=0.881st+0.039chl+1.366qtz+1.040H2O the coefficients of which are calculated using the mineral analyses of the ideally univariant assemblage staurolite–chloritoid–chlorite–andalusite. Variations in the activity of the unsaturated component ZnO would affect the equilibrium temperature of the reaction and the reaction coefficients.
Porphyroblast rotation and the kinematic analysis of a small fold
Authors: Kennan Pádhraig S.
Published: May 2009

The sense and amount of rotation of small garnet porphyroblasts is found to vary from place to place on a fold. By correlating this variation with a proposed mechanism of formation of the fold, a tentative profile for the fold at the time of garnet growth is constructed.
The petrography and chemistry of the Obudu type hornblende peridotite (cortlandtite), Ogoja Province, Eastern Nigeria.
Authors: Orajaka S.
Published: May 2009

The Obudu hornblende peridotite is described and briefly compared with similar rock types from other areas. Field evidence, petrographic studies, mineralogical and chemical composition have led to the conclusion that this rock is an independent magmatic intrusion into the hypersthene tonalite (enderbite) with which it is associated, and not a member of a differentiated series.
Zircon populations in Lewisian quartzite, gneiss and granite north of Loch Laxford, Sutherland
Authors: Chowdhary P. K.
Published: May 2009

Zircon populations in quartzo-feldspathic gneisses of the Rhiconich group of the Lewisian are indicative of a sedimentary derivation of the rocks. They are similar to the zircon population of an interbanded quartzite but differ markedly from that of an intrusive granite vein.
Geochronology of the Pre-Cambrian rocks of Singhbhum and adjacent regions, Eastern India
Authors: Sarkar S. N. , Saha A. K. , Miller J. A.
Published: May 2009

Tectonic implications of 32 new potassium-argon age determinations of minerals and rocks of Singhbhum and adjacent regions are discussed along with those of recent structural, stratigraphic and petrologic studies, and some pre-existing geochronologic data. Three distinct orogenic cycles with closing dates atc. 3200, 2700 and 850 m.y. respectively have been recognized. The earliest cycle is represented by the Older Metamorphic Group of metasediments with associated basic intrusives and biotite granodiorite gneiss; they occur mainly as relics within the huge Singhbhum granitic complex. Emplacement of the latter (c. 2700 m.y.) marks the culmination of the Iron Ore orogenic cycle which is characterized by the low-grade metamorphic Iron Ore Group sediments and volcanics and associated basic intrusives. Along the northern and eastern edges of the stabilized Iron Ore orogenic belt, thick sedimentation of the Singhbhum and Gangpur Groups (?2000–1700 m.y.) was followed by large scale basic volcanic activity (1700–1600 m.y.); these rocks were folded and regionally metamorphosed in several phases betweenc. 1550 andc. 850 m.y. (Singhbhum orogenic cycle); extensive thrusting and granitization occurred in the later part of the cycle.
The stratigraphical distribution of Bathonian ammonites in Central England
Authors: Torrens H. S.
Published: May 2009

A correlation of the predominantly limestone deposits of the Bathonian (Middle Jurassic) stage in Central England is presented on the basis of the available ammonites. This is related to the standard sequence of Bathonian zones, which are briefly discussed in the introduction. All ammonites from the area of stratigraphic importance are listed. There is nothing to suggest that any of the zones are absent because of erosion or nondeposition, except in the East Midlands at the base of the Bathonian.
A redescription of the Llandoverian monograptid “Graptolithus” tenuis, Portlock, 1843
Authors: Hutt Jana
Published: May 2009

The type specimen, other figured specimens and supplementary material of Monograptus tenuis (Portlock, 1843) have revealed the presence of pronounced ventral apertural processes which place this species in a unique position in the Monograptina. The affinities of M. tenuis are discussed.
The main features of the tectonic structure of Spitsbergen
Authors: Sokolov V. N. , Krasiltchikov A. A. , Livshitz Ju. Ja.
Published: May 2009

The Spitsbergen archipelago is situated in the north-westernmost part of the Barents Shelf. The structural position of the archipelago and the variety of its geological complexes make this region very important for understanding the tectonic history of the Atlantic sector of the Arctic.
An aberrant species of Fibularia from Kenya and Madagascar
Authors: Stephenson D. G.
Published: May 2009

Echinocyamus woodi Currie from the Miocene of Kenya is reexamined and considered to be conspecific with Fibulina gracilis Tornquist and Fibularia voeltzkowi Tornquist. This echinoid is a fibularid, not a laganid.
Pyrite Staining of Pellety Debris in Carbonate Sediments from the Middle East and Elsewhere
Authors: Sugden W.
Published: May 2009

Various limestones of Middle Jurassic and younger age in the Middle East and Britain, and certain Recent calcareous marine sediments contain pellety debris stained grey or black with finely divided pyrite. The staining appears to involve deposition on pellety debris of limonite, followed by its reaction with bacterially produced hydrogen sulphide to form first ferrous sulphide and subsequently pyrite.
Lower Cretaceous Palaeogeography of North-West Europe
Authors: Kaye P.
Published: May 2009

The Lower Cretaceous Palaeogeography of the British Isles and surrounding areas is postulated from micropalaeontological and stratigraphical evidence and its implications discussed.
On the occurrence of Parabrograptus and Sinograptus from the Middle Ordovician of Western Canada
Authors: Jackson D. E.
Published: May 2009

Specimens of Parabrograptus and Sinograptus from western Canada are described for the first time. An amended diagnosis of Parabrograptus is given. One pyritized fragment of a sinograptid stipe exhibits characters intermediate between Holmograptus and Sinograptus.
A New Occurrence of Sapphirine and Related Anthophyllite from Central Australia
Authors: Hudson D. R. , Wilson Allan F.
Published: May 2009

Phlogopite-spinel-bronzite rocks, in which aggregates of bronzite and sapphirine appear to be pseudomorphs of aluminous anthophyllite, occur in a restricted low-granulite terrain in the Strangways Range, central Australia. The form of the postulated reaction is gedrite + ΔH = enstatite + sapphirine + silica + escaping “ water ”.
The Emplacement of the Main Glencoe Fault-Intrusion at Stob Mhic Mhartuin
Authors: Roberts John L.
Published: May 2009

The contact relationships of the Fault-Intrusion are described, in detail, from the type locality. Textural and mineralogical evidence indicates that the fine-grained marginal facies of the Fault-Intrusion is not a priori evidence for magmatic emplacement. The production of “ flinty crush-rock ” from brecciated quartzites downfaulted within the Glencoe cauldron is described from the south-western inner contact, and is shown to be a result of gas attrition. “ Flinty crush-rock ” is recorded for the first time from the north-eastern contact with the country rocks outwith the cauldron, separated from the latter by a sheared microbreccia not found at the inner contact. The contact relations of the Fault-Intrusion with these “ flinty crush-rocks ”, more properly termed pseudotachylites, indicates that the Fault-Intrusion was emplaced as an entrained fluidized system of gas, solid phenocrysts and, probably, liquid droplets. The production of the sheared microbreccia at the outer contact is thought to be due to shearing stresses exerted by the entrained system on the heated wall-rocks.
Minnivola sapolwanaensis, new species, from the Miocene of Zululand, South Africa
Authors: Carter A. N.
Published: May 2009

A new species of Minnivola is described, from late Miocene lime-stone occurring in the valley of the Umfolosi River in Zululand, South Africa. The species extends the known range of the genus into the East African region and is distinguished by the presence on the adult right valve of about thirty-two ridges arranged in bundles of four, with prominent grooves between the bundles.
Amygdaloid Textures in the Lewisian Rocks of the Island of Tiree
Authors: Sinclair I. G. L.
Published: May 2009

Certain amygdaloid textural features have been observed in a diopside-potash felspar rock within the Lewisian of the Island of Tiree; so far as the writer is aware, such features have not previously been noted in Lewisian rocks.

Evidence as to the genesis of these textures is sparse but they appear to have attained their present nature after the principal metamorphic events which have affected the enclosing rocks.
A Miocene Gravity Slide Deposit from Eastern Timor
Authors: Audley-Charles M. G.
Published: May 2009

A formation composed of unbedded scaly bentonitic clay containing abundant scattered exotic blocks, boulders, pebbles, and smaller fragments is described from eastern Timor. It is proposed to call this formation the Bobonaro Scaly Clay. This formation is compared closely with the Argille scagliosa of the northern Apennines. Its origin is ascribed to submarine sliding of an unstable clay mass from the area north of Timor under the influence of gravity, closely associated with the emplacement of large overthrust slices of strata that marked a climax of the mid-Tertiary orogeny in Timor. The discovery of this formation has helped to bring about a radical revision of the published views of the stratigraphy and structure of Timor.
Late Orogenic Events in the Northern Part of the Moine Nappe
Authors: Soper N. J. , Brown P. E.
Published: May 2009

Conjugate folds are recorded in Moine rocks some 15 miles east of the Moine thrust zone and their association with lamproschists and regional joint systems is described. This, and other evidence, is used to establish a sequence of late Orogenic events for the interior of the Moine nappe. A correlation with events in the thrust zone is suggested. It is concluded that the Moine thrust movements took place in Lower Old Red Sandstone times and that this coincided with a period of rapid isostatic uplift of the axial region of the Caledonian orogen.
The Torridonian Succession on the Islands of Fladday, Raasay, and Scalpay, Inverness-shire
Authors: Selley R. C.
Published: May 2009

The succession of the Torridonian rocks seen on the islands of Fladday, Raasay, and Scalpay is described. Three lithological fades indicative of three distinct sedimentary environments are recognized. Breccias and grits, believed to be sub-aerial in their lower part, are overlain, or pass laterally into, grey shales and sandstones of lacustrine or shallow water marine origin. These are succeeded by red fluviatile sandstones and shales, which, except near the base, are coarse grained and pebbly throughout much of the succession. Three cases of lateral facies variation are described and their significance discussed with regard to the Torridonian succession elsewhere in the Inner Hebrides and on the mainland.
Non-Metasomatic Chlorite in Igneous Rocks
Authors: Lehmann E.
Published: May 2009

The determination of the stability conditions of chlorite, especially the stability temperature between 500° and 700° C. by B. W. Nelson, D. M. Roy, R. Roy, and H. S. Yoder complements the conclusions arrived at from the microscopical study of the interstitial chlorite in the diabase-minverite series of south-west England. These disprove the assumption that the chlorite generally originates from metasomatic reaction or devitrification of a glassy residue. Considering the formation of chlorite at a late stage of solidification, an explanation of its genesis is attempted on that basis. Possible effects on the petrologic evolution are discussed.

The chlorite taking part in the filling of amygdales and pseudoamygdales has formed preferentially by replacement of carbonates. Variation in form, degree, and associated products is exemplified. The appearance of a liquid carbonate phase, ascertained by P. J. Wyllie, O. F. Tuttle, and R. I. Harker in the system calcitewollastonite-water at temperatures between 640° and 680° C. seems to be realized likewise under natural conditions, and to provide a basis for the understanding of certain phenomena, especially in reaction zones.
On the Symmetry Principle and the Deformation Ellipsoid
Authors: Flinn Derek
Published: May 2009

According to the symmetry principle the fabric of a tectonite reflects the symmetry of the deforming movements. Where the symmetry of the deformation varies from place to place this should be reflected in a similar variation in the fabric. The possible variation in homogeneous strain is best shown by the range of variation possible in the deformation ellipsoid. It is argued in the paper that rocks commonly occur which show a variation in fabric from place to place similar to the whole or part of the possible variation in shape of the deformation ellipsoid. It is concluded that such rocks have deformed by homogeneous strain. This conclusion is supported by the shapes and orientations of pebbles in deformed conglomerates.
Quartz Keratophyre Sills Intruded into Unconsolidated Sediments in North Queensland, Australia
Authors: Morgan W. R.
Published: May 2009

Quartz keratophyre sills interbedded with folded Devonian sediments in the Annan River Tinfield area in North Queensland have probably been intruded when the sediments were unconsolidated or only partly consolidated. The sills are compared with similar occurrences in Wales, Alaska and Australia. Some of these may have been extruded prior to burrowing into sea-bottom muds but the North Queensland examples are probably true, though very high-level, sills.
The Niger Delta Region in the Light of the Theory of Continental Drift
Authors: Stoneley R.
Published: May 2009

A recently computed fit of the African and South American continents is astonishingly close, apart from an overlap of some 120 miles in the vicinity of the Niger delta. This paper attempts to determine whether there is a genuine misfit at this point or whether the delta may have grown beyond the continental margin after the continents separated. The evidence suggests that final separation took place in Albian times, and that the bulge of the present continental edge into the Atlantic Ocean has resulted from post-Cretaceous development of the delta. The gross structure of the delta region and also the associated minor structures are considered to represent a passive response to the influx of sediment from the Niger River.
On the Magnetic Age of some Devonian Lavas from Devonshire
Authors: Cornwell J. D.
Published: May 2009

The directions of magnetization of samples from two sites in the Devonian Ashprington Volcanic Series, Devonshire, are similar in spite of the difference in the dip of the lavas. They are close to the mean direction for the Keuper Marls and it is concluded that they resulted from remagnetization of the lavas during the Triassic.
Fold Structures in the Mylor Beds, near Porthleven, Cornwall
Authors: Stone Maurice
Published: May 2009

Early folds (F1) in the Mylor Beds are upright or overturned to the north-west and trend north-easterly. They are cut by a flat-lying cleavage (S2) which is related to small-scale recumbent folds (F2) superimposed on the steep limbs of the early folds. The sequence of development of folds can be found elsewhere in the Mylor-Gram-scatho Beds and also in the Lizard Head mica schists. It is shown that F2 folds and S2 cleavage resulted from vertical shortening, which is believed to have been caused by the superimposition of slide sheets. It is suggested that the previously accepted age order of the Mylor and Gramscatho Beds should be reversed.
Kaolin Tonsteins in the Westphalian of North Staffordshire
Authors: Barnsley G. B. , Clowes J. M. , Fowler W.
Published: May 2009

The character, horizon, and extent of ten kaolin tonsteins occurring in the Westphalian strata of the North Staffordshire Coalfield are described, and four additional horizons considered worthy of further study, when this is possible, are noted. The value of these kaolin tonsteins in correlation, and the possibility that they may fall into two groups having different origins, is briefly discussed.
Geophysical Investigations on the Boundaries of the Mountsorrel Granite
Authors: Davies D. , Matthews D. H.
Published: May 2009

As a result of magnetic, seismic, and gravitational studies it has been possible to describe the nature of the boundaries of the Mountsorrel granite massif in more detail. Confirmation has been found of faulting postulated on other grounds; and also it is shown that there is no substantial underground extension of the granite beneath the surrounding Triassic countryside to the west of the outcrop.
A Columnar Growth of Dendritic Pyroxene
Authors: Preston J.
Published: May 2009

One of the internal contacts of a doleritic intrusion, Co. Donegal, is lined with large augite dendrites. The habit is revealed by parting on a median zone of chlorite which is regarded as an altered exsolution feature. It is suggested that an initial platy dendrite grew, in response to undercooling, as a metastable phase with the composition and structure of a high-calcic pigeonite. A later overgrowth of augite preserved the delicate crystal against destruction.
Cordierite and wollastonite-bearing rocks of south-western Ceylon
Authors: Hapuarachchi D. J. A. C.
Published: May 2009

In the region east of the south-western belt of Ceylon, garnet is stable in biotite-bearing pelitic rocks which belong to the hornblende-granulite subfacies. In the south-western belt, which includes Zone B of the eastern part of the Gampaha sheet, garnet is unstable in biotite-bearing pelitic rocks, garnet reacting with biotite to produce cordierite which has a widespread occurrence in the belt to which it is confined. To accommodate the stable cordierite-bearing pelitic assemblages the erection of a cordierite-granulite subfacies is necessary. Wollastonite-bearing rocks, which commonly occur in the belt and are confined to it, belong to the cordierite-granulite subfacies.
Cruziana: A stratigraphically useful trace fossil
Authors: Crimes T. P.
Published: May 2009

Cruziana semiplicata (Salter) is recorded, generally in abundance, from previously known and new localities within Upper Cambrian (Ffestiniog) sediments in Snowdonia, and the Portmadoc area, North Wales. C. furcifera (D'Orb) is recorded for the first time in the British Isles from four localities within Lower Ordovician (Arenig) sediments on St. Tudwal's Peninsula, North Wales.

It is shown that each of these species is of limited but different range, and it is suggested that they could be useful in distinguishing between otherwise unfossiliferous Cambrian and Ordovician strata.
A note on some garnetiferous biotite schists from Gangpur, Eastern India, and their polyphase metamorphism
Authors: Choudhuri A.
Published: May 2009

Textural features of two types of garnetiferous biotite-schists from the Iron-ore Series, Gangpur, developed at and near Potob, Ranchi District, indicate stages of development of the two rocks and their polyphase metamorphism.
Oolites and deformation
Authors: Kumar Surendar
Published: May 2009

A study in the deformational patterns of oolites from the Krol Series of the Simla Himalayas has been made in the type area. The deformation in the oolites is the result of the tectonic phenomenon coupled with folding movements during the Himalayan orogeny. The deformation varies with the amount and type of the matrix surrounding the oolites. The angle between the long axis of the ellipse and the principal tectonic extension is smallest in the axial regions of the folds.
The quartz-plagioclase gneisses of Western Connemara, Ireland
Authors: Benjamin R. E. K.
Published: May 2009

Chemical analysis of twenty-six amphibolite facies gneisses from western Connemara are treated statistically, and used in conjunction with petrographic evidence to elucidate their origins. It is shown that the gneisses are of igneous ancestry, and have been invaded by material of silica-soda potash composition. The conditions of temperature and pressure prevailing at different times is related to the evolved mineral assemblages, and the whole sequence fitted into the general pattern of events in Connemara.
On Pyroxene Molecules in the CIPW Norm
Authors: Chayes F.
Published: May 2009

Barth argued that the CIPW conventions governing the calculation of normative pyroxenes and olivines are based upon inadequate or incorrect mineralogical information and should be abandoned. The real occasion for the conventions appears to be petrological, not mineralogical. Qualitative agreement between norms and modes of undersaturated rocks requires the use of these or very similar conventions. Ease of calculation is no longer a major consideration and a more realistic set of rules could now be adopted if it were available.
A Possible Fossil in a Graphitic Marble in the Connemara Schist, Cornamona, Co. Galway, Ireland
Authors: Leake Bernard E.
Published: May 2009

A network texture made of graphite with calcite filling the holes is described from an area of staurolite-garnet grade of metamorphism. It is pointed out that this is the earliest texture preserved in the rock, and that it resembles a cellular structure and may therefore be of organic origin, possibly a primitive plant. At present, however, it is not certain that the structure is organic in origin.
On the Occurrence of Two Intersecting Pre-Cambrian Orogenic Belts in Singhbhum and Adjacent Areas, India
Authors: Sarkar S. N. , Saha A. K.
Published: May 2009

Intensive structural and stratigraphic studies, supplemented by nine new absolute age data, have led to the recognition of two distinct orogenic belts in the Pre-Cambrian tract of Singhbhum and adjacent areas in India. The Iron Ore orogeny in the south, characterized by the generally low grade metamorphic, N.N.E.–S.S.W. trending formations, had its culmination in the emplacement of the batholithic body of Singhbhum granite (c. 2,000 m.y.). These rocks are separated by a prominent thrust zone (Copper Belt thrust) from the E.–W. striking, generally high-grade meta-morphic rocks of the Singhbhum orogeny whose closing age is 905 to 934 m.y.
Pyrothalassite and the evolution of volcanic islands
Authors: Middlemost Eric A. K.
Published: May 2009

It is proposed that the term pyrothalassite should be used to describe the materials that form the outer and upper covering of a volcanic edifice that rises from the sea bed, and it includes the fragmental materials produced by hydroexplosions and surf action in the upper layers of the sea. This material is both porous and enriched in thalassophile elements. These two characteristics give a pyrothalassite layer the ability to exert a profound influence on the magmatic evolution of volcanic islands that contain, or contained, such a layer.
The Caledonoid faults of northern Lleyn (North Wales)
Authors: Tremlett W. E.
Published: May 2009

Evidence of substantial dextral strike-slip displacements along the Caledonoid fault-set of northern Lleyn is revealed by the distribution of Pre-Cambrian igneous and metamorphic rocks, Ordovician volcanic rocks and Caledonian ‘early granodioritic’ intrusions. These apparently occurred prior to some smaller sinistral strike-slip movements which left total net dextral displacements of 91/2 km. Both types of movement were completed before the Caledonoid faults were disrupted by NNW sinistral faulting and more intrusions of Lower Old Red Sandstone age were emplaced.
A Pyroxene – Hornfels from the Basic Plutonic Complex, Co. Tyrone, Ireland
Authors: Angus N. S.
Published: May 2009

A basic augite-hypersthene-hornfels, which escaped a subsequent regional amphibolite facies metamorphism, is preserved adjacent to a gabbroic intrusion of the Basic Plutonic Complex. The hornfels and two dolerites have been analysed and their compositions compared with similar rocks from Duluth and Skye. It appears that Si, Na and K have been removed from the dolerites, and the resultant hornfels relatively enriched in Fe, Mg, Ti and Ca.