bluuebunny/crossref_metadata_2025 huggingface dataset:
The petrology and geochemistry of the Creag Dubh composite sill, Whiting Bay, Arran, Scotland
Authors: Rogers N. W. , Gibson I. L.
Published: May 2009

Analysis of 17 samples for both major and trace elements reveals that, unlike most other Tertiary composite intrusions, the Creag Dubh sheet possesses silicic margins and a doleritic centre. The two rock types grade together rapidly without chilling at the upper and lower internal contacts. However, there is evidence for mixing of the two magma types prior to or during emplacement with the production of limited amounts of intermediate hybrids. The central dolerite appears to be later than the marginal felsites which in places back-vein the dolerite. The sequence of intrusion is tentatively related to the upward draining of a strongly zoned magma chamber.
Submarine volcanic and associated sedimentary rocks of the Fuerteventura Basal Complex, Canary Islands
Authors: Robertson A. H. F. , Stillman C. J.
Published: May 2009

On Fuerteventura, inner Canary Islands, a phase of early Cretaceous deposition on a passive continental margin was terminated in Albian time by strong localized uplift associated with onset of calcareous pelagic sedimentation. Later, during early Tertiary times, spasmodic episodes of submarine alkali volcanism led to the construction of a thick lava pile. After folding of the lower submarine volcanic rocks, and the underlying pre-volcanic sedimentary rocks, parts of the Basal Complex were emergent by Oligocene to Miocene times, fringed by coral and algal reefs. With renewed early Miocene uplift, the reefs disintegrated, followed by block faulting, intrusion of plutons, and a final phase of submarine dyke intrusion. There was then strong uplift coupled with deep erosion, extrusion of sub-horizontal Neogene plateau lavas and further intrusion of plutons. Regional comparisons suggest that tectonic events on Fuerteventura may have a bearing on sedimentary hiatuses and gravity sliding events which affected the adjacent West African continental margin.
Coccolith-rich marker bands in the English Kimmeridge Clay
Authors: Gallois R. W. , Medd A. W.
Published: May 2009

Thin coccolith-rich bands, in which coccoliths make up a major part of the rock, have been recorded at 11 horizons in the Kimmeridge Clay of Yorkshire, Lincolnshire, Norfolk, Surrey and Wiltshire and also in cliff sections at and adjacent to Kimmeridge Bay, Dorset. It seems likely that at least nine of these bands form persistent markers throughout southern and eastern England. The coccolithophorid assemblages are discussed and some species of Stradnerlithus are systematically described.
Tektites probably wholly terrestrial and related to continental movement
Authors: Crawford A. R.
Published: May 2009

The four groups of tektites are now widely regarded as the product of splash from a meteoritic or cometary impact melt of terrestrial rock. They include two groups (Moldavites and Ivory Coast tektites) attributed to the Nordlinger Ries and Bosumtwi craters. These craters seem unlikely to be of impact origin, though hyper-explosive. Tektites are, therefore, more probably all wholly terrestrial. For much the largest group, those of the combined Southeast Asian-Australian strewnfield, no satisfactory source is known. An origin in Southeast Asia, even by impact, is improbable. A possible source lies in Central Asia. The hyper-explosive activity is regarded as an extreme form of volcanism, a consequence locally and rarely of the continual combined vertical and ‘horizontal’ movements of continents, here termedtribulation.
Rootless vents in welded ash-flow tuffs from northern Snowdonia, North Wales, indicating deposition in a shallow water environment
Authors: Wright J. V. , Coward M. P.
Published: May 2009

In northern Snowdonia welded ash-flow tuffs, correlated with the Pitt's Head Tuff Formation occur intercalated with Caradoc shallow marine shelf sediments. Within the tuffs there are vent-like structures which have a diapiric form where fiamme are drawn in towards a central core. The cores may have a constrictional linear fabric of streaked out fiamme, or may consist of vitrous tuff surrounded by a zone of buckled planar fiamme. There are associated zones of quartz nodules which are thought to represent quartz filled vesicles. The diapiric structures are believed to be rootless vents. Steam generated by the heat of the flow in contact with shallow water is thought to have caused explosive disruption of the tuffs as consolidation and welding occurred. These structures are thus themselves indicators of deposition of ash-flow tuffs in a shallow water environment.
Comparative petrography of deformed and undeformed migmatites from the Grampian Highlands of Scotland
Authors: Ashworth J. R.
Published: May 2009

Fabrics in migmatites from Portsoy in the NE Dalradian are compared with those in paratectonic and pretectonic migmatites from deeper structural levels of the Northern Grampain Caledonides. Paratectonic leucosomes, from Portsoy and Mid-Strathspey, have weak biotite fabrics. They lack the biotite foliation which is strongly developed in pretectonic leucosomes from the Upper Findhorn area. In conjunction with the sequence of deformation, intrusion and metamorphism in Banffshire, the fabric data indicate that migmatization at Portsoy was paratectonic with respect to the local F, folding. Partial melts generated in the aureole of the pre-F3 basic intrusions were, in some rocks, still mobile during F3 and completely crystalline only after the formation of small F3 folds. Granitic leucosomes in Mid-Strathspey were formed within the time-span of a deformation episode. Petrographic measurements show that these leucosomes have approximately minimum-melting compositions in Qz-Ab-An-Or, despite some deformation and retrograde alteration. They are comparable with the Portsoy migmatites in grain size and in complexity of leucosome shapes, and they are tentatively interpreted as products of incipient partial melting without dehydration of biotite.
Mixed benmoreite/trachyte flows from Kenya and their bearing on the Daly Gap
Authors: Jones W. B.
Published: May 2009

Blebs of anorthoclase-phyric purple rock, usually up to 10 cm but occasionally up to 30 cm in diameter, occur in trachyte lavas of the volcanoes Kilombe and Kapkut, Kenya. The blebs have bulbous outlines and chilled margins and are therefore considered to have been liquid when incorporated in the trachyte. Chemically similar to the benmoreites of Hawaii, Skye and the southern Kenya Rift Valley, they bridge a gap in an otherwise complete sequence of lavas from basalt to trachyte. The failure of benmoreite to erupt as a lava is attributed to viscosity reaching a maximum among intermediate lavas.
The occurrence of Mesozoic oceanic floor and ancient continental crust on South Georgia
Authors: Storey B. C. , Mair B. F. , Bell C. M.
Published: May 2009

The Larsen Harbour Formation of southern South Georgia is part of an ophiolite sequence of submarine lavas and sheeted dykes emplaced into metasedimentary country rocks. The metasediments are remnants of a pre-Cretaceous continental crust which had been subject to regional metamorphism and polyphase deformation prior to intrusion by a variety of acid and basic igneous rocks (roots of the ophiolitic sequence). It is proposed that the segment of continental crust and the Larsen Harbour Formation formed the floor of a back-arc basin which was infilled during Early Cretaceous time by a thick sequence of volcaniclastic sediments (Cumberland Bay Formation).
The sillimanite zones of the Huntly-Portsoy area in the north-east Dalradian, Scotland
Authors: Ashworth J. R.
Published: May 2009

The distribution of andalusite, kyanite and sillimanite in an important part of the NE Dalradian is mapped. Sillimanite represents a late episode overprinted on the regional Andalusite and Kyanite Zones. The spatial distribution of sillimanite confirms that the heat source for the sillimanite-grade metamorphism in this area was the Newer (or Younger) Basic magma. The sillimanitic aureole of the Newer Basic intrusives is divisible into a Sillimanite Zone and a higher-grade Sillimanite—potash feldspar Zone. Relict andalusite is common in the Sillimanite Zone. Coarse muscovite replacing other minerals is primary in both zones, and should not be confused with late retrograde effects. Electron-probe analytical data on the Sillimanite–potash feldspar zone paragenesis of muscovite are presented. In this, its type area, the so-called ‘Boyne Line’ does not exist; the concept of such a tectonic dislocation arose through misinterpretation of the metamorphic effects.
A postulated post-Hercynian rift valley system in southern Britain
Authors: Whittaker A.
Published: May 2009

It is suggested that post-(Hercynian)orogenic tensional forces may have initiated a major rift valley system in the Palaeozoic rocks of southern Britain. Large graben structures may underlie the Bristol Channel, the Severn Basin and the Weald Jurassic trough. Smaller graben structures are present in Devon and are associated with extrusive, potassium-rich lavas. The bounding faults of the larger postulated grabens may have been active during early Mesozoic times and may have fundamentally controlled sedimentation in local sags. A model is proposed which ascribes the development of fault-bounded Permo-Triassic basins and Jurassic axes of uplift to fracturing in the Palaeozoic basement.
Late Precambrian glacial climate and the Earth's obliquity
Authors: Williams G. E.
Published: May 2009

Late Precambrian (∼ 750±200 Ma) glaciogenic sequences exhibit substantial evidence for marked climatic inequability of seasonal and longer periodicity (10° to ∼ 106yrs): (1) tillites are closely associated with dolomites, limestones and evaporites apparently of warm-water origin; (2) tillites occur with red beds and iron-formations whose iron probably was derived ultimately from lateritic weathering; (3) glacial dropstones occur locally within carbonates and iron-formations; (4) laminae, interpreted asvarvesby many workers, are common in argillites, carbonates and iron-formations; and (5) permafrost structures attributable to repeated seasonal changes of temperature are locally abundant. Such climatic, particularlyseasonalinequability apparently conflicts however with the probable low (≲30°) palaeolatitudes of deposition of numerous late Precambrian glaciogenic sequences.

The contradictions presented by such sequences may be resolved by postulating a considerably increased obliquity of the ecliptic (ε) in late Precambrian time. Substantial increase in e would: (1) greatly amplify global seasonality; (2) weaken climatic zonation, thus allowing warm-water sedimentation and lateritic weathering over wide latitudes; and (3) increase the ratio of radiation received annually at either pole to that received at the equator, so when 54° < ε < 126° low and middle latitudes (≤ 43°) would be glaciated in preference to the poles. Ice sheets and permafrost thus can be envisaged principally in low and middle latitudes with contiguous warm-water and iron-rich facies under a markedly seasonal climate. The concept of secular change of e is supported by other geological evidence.
The crystallization of the teschenite from the Lugar Sill, Ayrshire
Authors: Phillips W. J.
Published: May 2009

Twelve stages in the crystallization of the teschenite are defined by the commencement or cessation of crystallization of particular minerals. Ocellar structures, outlined by tangentially arranged biotite flakes, developed in liquid pockets after the sill had begun to consolidate, due to the coalescence of crystalline masses. It is thought that these ocellar structures were formed by the growth of gas bubbles and that this caused the expansion and fracturing of the partially consolidated sill. It is argued that the separation of the gas phase was the result of a retrograde increase in the vapour pressure during crystallization.
Sedimentary and igneous trends on AFM diagrams
Authors: Robinson D. , Leake B. E.
Published: May 2009

It is pointed out that some chemically analysed sedimentary rock series when plotted on AFM diagrams (A = Na2O + K2O; F = total iron as FeO; M = MgO) partly mimic trends generally considered characteristic of igneous variation, especially the calc-alkali trend. Although the scatter in sedimentary rock plots is generally greater than that given by igneous rocks this is not necessarily so for calc-alkali suites often show considerable scatter. These observations should be considered when deducing the origin of highly metamorphosed gneisses and quartzo-feldspathic rocks that might be meta-arkoses, meta-granites or meta-volcanic rocks.
Petrochemistry of Paleozoic spilites of the eastern Alps (Austria)
Authors: Loeschke J.
Published: May 2009

In the Karawanken Mountains (SE Austria) spilites (pillow lavas and sills) are found intercalated in a sequence of Paleozoic slates and graywackes. The petrogenesis of these spilites is interpreted as follows: The pillow lavas and sills consolidated as mugearites and hawaiites, which were derived from an alkali olivine-basaltic magma by fractional crystallization. Under low temperature metamorphic conditions water entered into the rocks predominantly from external sources. The primary minerals (Na-Ca plagioclase, pyroxene and glass) were thus replaced either partially or completely by minerals characteristic of spilites (albite, chlorite, epidote and others). The spilites analysed are of secondary origin. They are compared with spilites and basalts of other (continental and oceanic) areas.
Evidence of Precambrian block-faulting in the western margin of the Afar depression, Ethiopia
Authors: Kazmin V. , Garland C. R.
Published: May 2009

Regional mapping in the eastern escarpment of the Ethiopian plateau indicated Precambrian block-faulted structures which have been felt in sedimentation and tectonics for more than 1000 m. y. and which controlled to some extent the opening of the Afar.
Some conventional potassium–argon and 40Ar/39Ar age studies of glauconite
Authors: Brereton N. R. , Hooker P. J. , Miller J. A.
Published: May 2009

40Ar/39Ar age studies of some glauconites from well-known stratigraphical horizons reveal unexpectedly high ages compared with the conventional K–Ar age determinations. These have been interpreted in terms of nuclear and physico-chemical reactions sustained by the glauconites in the reactor. These impose severe limitations on the use of glauconite in the 40Ar/39Ar irradiation technique.
Coignouina decora sp. nov. and Carbonocoryphe hahnorum sp. nov. (Trilobita) from a Viséan fissure deposit near Clitheroe, Lancs
Authors: Miller J.
Published: May 2009

The fauna of a Lower Carboniferous (S1) fissure near Clitheroe, Lancashire, is listed. Coignouina acanthina sp. nov. (Otarionidae) is described, together with its unusual ‘eye-mound’ which bears tubercles rather than lenses. Note is made of new material of C. acanthina (Coignou) which necessitates modification of Osmólska's (1967) reconstruction of the cephalon. Carbonocoryphe hahnorum sp. nov. (Proetidae) is also described and a brief account presented of its variation, postlarval ontogeny and palaeo-ecology.
The Metamorphism of the Manx Slate Series, Isle of Man
Authors: Simpson Alexander
Published: May 2009

Previous research by the present author has established the Caledonian tectonic history of the Manx Slate Series. In particular three episodes of folding (F1, F2, F3) were recognized. The present contribution describes the sequence of metamorphic textures impressed on these metasediments during this polyphase deformation.

Two distinct episodes of metamorphism have affected the Manx Slate Series. A syn-tectonic F1 metamorphism produced a chloritezone alteration throughout the Island. A later F2 metamorphism was primarily responsible for the growth of small porphyroblasts of several minerals within the pre-existing F1 fabric. This second metamorphism is confined to the hinge of the large-scale F2 Manx synform and its effects are visible in an elongate belt following the middle of the Island. The emplacement of the porphyroblasts began during the F2 movement and continued into the static interval which preceded the third (F3) movement-phase. It was completed prior to the F3 deformation.
A Study of Possible Factors concerning Garnet Formation in Rocks from Ardara, Co. Donegal, Ireland
Authors: Jones K. A. , Galwey A. K.
Published: May 2009

Chemical and modal analyses have been made for a series of ten homogeneous specimens of meta-sediments, with identical metamorphic histories, from the aureôle of the Ardara pluton. Results showed that total amount of garnet was determined by the quanity of “free ferrous oxide” (assuming that the reaction: FeO + Fe2O3→ Fe3O4, has gone to completion) in the rock. Size distribution curves showed that each specimen contained crystals with a preferred radius and throughout the series a quantitative relation between the preferred radius and the frequency distribution about this value was observed.

Measurement of the number of crystals per unit volume showed that this gave trends with functions of the chemical composition of the rock. A discussion of the mechanism of garnet formation in terms of chemical laws of nucleation and growth is given.
The Pre-Cambrian and Lower Palaeozoic Rocks of South-east Co. Wexford, Eire
Authors: Crimes T. P. , Dhonau N. B.
Published: May 2009

The pre-Carboniferous rocks exposed along the coast of Co. Wexford from Rosslare to Bannow Island have been re-examined. Four distinct units are recognized: the Rosslare Complex, the Cul-lenstown Group, the Tagoat Group and the Bannow Group.

The Rosslare Complex and the Cullenstown Group are suggested to be of Pre-Cambrian age. A correlation is proposed between the Cullenstown Group and part of the Mona Complex of Anglesey; the Rosslare Complex is thought to be much older. It is suggested tentatively that all the Bannow Group may be of Ordovician age.
The Polarisbreen Series and other evidences of late Pre-Cambrian Ice Ages in Spitsbergen
Authors: Wilson C. B. , Harland W. B.
Published: May 2009

Details of the Infra-Cambrian Polarisbreen Series are given, arising partly out of observations made since they were defined in outline by the authors in 1956. The Polarisbreen Series includes the distinctive Polarisbreen Tillite Formation, which correlated with the neighbouring Sveanor Formation of Nordaustlandet and with other tillites in Vestspitsbergen. They are regarded as a product of the great infra-Cambrian ice age and are correlated with world-wide tillite horizons of this age.
On the Association of an Indurated Basic Tuff and a Felsite Intrusion in the Kilchrist Vent, Skye.
Authors: Ray Prem S.
Published: May 2009

A metamorphosed basic tuff and a felsite and a felsite intrusion are described. Presence of laminar structure in the matrix of the tuff and of veinlets of tuff penetrating and acid xenolith enclosed in the tuff indicates that the fragmental assemblage moved in a manner similar in final effect to fluid injection. A felsite-tuff which grades into the felsite is thought to be the remnant of the emplaced material subsequently metasomatized in situ to produce the felsite.
Brood Pouches in the Devonian Brachiopod Uncites
Authors: Rudwick M. J. S.
Published: May 2009

Some, but not all, specimens of Uncites have a pair of pouches formed by invagination of the shell margin. These are interpreted as brood pouches. They are compared with the brood pouches of Lacazella and other living brachiopods, and of the living bivalves Thecalia and Milneria.
A Note on the Pleistocene Deposit at Grantchester, Cambridgeshire
Authors: Sparks B. W.
Published: May 2009

Examination of material from this locality kept in the Sedgwick Museum since 1881 has revealed much more about its molluscan fauna, especially about the frequency of species. It seems to have been a deposit of the main river Cam in the middle of the Last Interglacial.
The Graptolitic Mudstone and Associated Facies in the Silurian Strata of the Howgill Fells
Authors: Rickards R. B.
Published: May 2009

The graptolitic mudstones, which constitute an important facies of the Silurian strata of the region, are described, and their evolution in time is considered to reflect gradually changing conditions in the depositional environment. The associated facies are discussed and, where possible, their roles assessed.
The Late Pre-Cambrian Stratigraphic Sequence in the Scandinavian Mountain Chain
Authors: Hernes I.
Published: May 2009

A late Pre-Cambrian eugeosynclinal stratigraphic sequence in the western part of the Scandinavian mountain chain is established. In the Möre region the succession is about 11 km thick. The wellknown late Pre-Cambrian miogeosynclinal sequence in the eastern part of the chain corresponds to the upper part of the eugeosynclinal sequence.
The London Clay Surface in Part of Suffolk
Authors: Carr A. P.
Published: May 2009

The pre-Pliocene sub-aereal surface of the London Clay in the Orford area of Suffolk is discussed. It is shown that south of Aldeburgh the slope of the London Clay towards the north must be less than previously thought and that prior to the deposition of the Coralline Crag a major river ran approximately from south to north in the area studied. This river course may help to explain the sudden drop of the London Clay surface north of Aldeburgh which has not been fully accounted for previously.
Range, proportionate representation, and demise of brachiopod families through Permian Period
Authors: Waterhouse J. B. , Bonham-Carter G.
Published: May 2009

The time range and proportional distributions of Permian brachiopod families are summarized for the Permian Period. The ‘imperfection’ of the record is calculated from the apparent absences of families known to have survived. It is shown that the phylum changed in composition during the late Middle and Late Permian, with increased importance of Orthida, Strophalosiacea, and Oldhaminida at the expense of the Productacea. Changes were over-printed by loss of families, markedly later than the extensive contraction of shelf-seas, concurrent probably with significant changes in geo chemistry and trophic resources. A number of highly significant families survived into the time of renewed transgression during the Otoceras and Ophiceras ammonoid zones, usually classed at the base of the Triassic Period. The demise of most Permian families proceeded in concert with climatic changes, but the initial deaths of families appear to have been caused by some other unknown factor, which may have severely disrupted Permian communities and biomes, and caused them to respond more than usual to climatic oscillations.
Isotopic age data from Scourian intrusive rocks on the Isle of Barra, Outer Hebrides, north-west Scotland
Authors: Francis P. W. , Moorbath S. , Welke H. J.
Published: May 2009

Rubidium–strontium and potassium–argon measurements on Lewisian intrusive rocks, considered to be late Scourian in age on general geological grounds, have indeed yielded dates in the range 2450–2600 m.y. This demonstrates that rocks of Scourian age that have escaped substantial Laxfordian reworking are preserved in the Eastern Gneisses of Barra. The relevant geological consequences and correlations are briefly discussed. A cross-cutting late pegmatite yields a typical Laxfordian date of 1679 m.y.
Petrogenesis of Cenozoic sediments of north-western Himalayas
Authors: Chaudhri R. S.
Published: May 2009

Cenozoic rocks of north-western Himalayas (excluding the sub-Recent, Recent and Karewa deposits) are represented by the Subathu, Dagshai, Kasauli and Siwalik rocks, which together have a thickness of over 10,000 m and range in age from Upper Palaeocene to Middle Pleistocene. From field and laboratory investigations it is propounded that these sediments, except the Middle and Upper Siwalik, have been derived from low and medium grade metamorphic rocks, acid plutonics and sedimentary rocks of the nearby Himalayan terrains. For the Middle and Upper Siwalik rocks, detritus was supplied by sedimentary and trap rocks as well as by the underlying medium and high grade metamorphic and plutonic rocks. A major part of these sediments has been derived from the rising Himalayas rather than from the Peninsular Shield as believed hitherto. The Subathu rocks were deposited in shallow to moderately deep marine environments; the Dagshai rocks under shallow freshwater conditions; and the Kasauli and Siwalik rocks in a shallow fast-sinking basin. All these sediments accumulated under conditions of rapid erosion, short transportation and rapid deposition.
A Tertiary thrust fault on the southern margin of the Bovey Basin
Authors: Bristow C. M. , Hughes D. E.
Published: May 2009

Geological investigations and borehole drilling on the southern margin of the Bovey basin around Mainbow ball clay mine and Ringslade open pit have shown that Devonian slate up to 30 m thick is superimposed on Tertiary sediments. A drag fold beneath the slate indicates that the slate has moved eastwards over the Tertiary material. As the slate is relatively intact and not disaggregated, hillcreep cannot be responsible for the superimposition. A large landslip involving a rotational shear cannot be responsible, as the movement plane dips into the hill over too large an area. The southern margin of the Bovey basin is therefore interpreted as a thrust fault of Tertiary age, with thrust plane dipping 10° to 30° S.
It is suggested that this is a rejuvenation of the Variscan thrust recognized in the Bickington area and further west in the Holne area and that the movement on the Tertiary thrust is related to the dextral wrench movement on the Sticklepath fault.
The origin of the Kunavaram amphibolites, Khammam District, Andhra Pradesh, India
Authors: Subbarao K. V.
Published: May 2009

Chemical and modal analyses of five Kunavaram amphibolites, together with mineralogical data on the pyroxenes and amphiboles, are given. Using petrochemical plots based on Niggli numbers, the trends of variation suggest an igneous origin.
The structure and intrusive mechanism of the Kap Edvard Holm layered gabbro complex, East Greenland
Authors: Elsdon R.
Published: May 2009

The complex can be divided into three units, here named the Lower, Middle and Upper Layered Series respectively, on the basis of petrochemical data and correction of the dips of the layering for the effects of post-consolidational flexuring. There are no chilled margins, and the contact with the country rock consists of granular basic and ultrabasic rocks, older than the cumulates of the layered series. The intrusive mechanism is considered in the light of field and chemical data.
Stromatolites from the Middle Old Red Sandstone of Western Orkney
Authors: Fannin N. G. T.
Published: May 2009

The structures are comparable with stromatolites seen in modern “flats” environments and tufa occurring in joints in the granite—gneiss basement is compared with modern and fossil forms. Finely laminated (? varved) carbonates with a large lateral persistency (1: 50,000) are referred to periods of high water level and are believed to show evidence of seasonal algal bloom. The presence of widespread stromatolite structures is consistent with earlier environmental interpretations of the Orkney rocks.
Taxonomy and stratigraphy of the Indian species of Discocyclina (foraminifera)
Authors: Samanta B. K.
Published: May 2009

Twenty-seven specific and subspecific names have been proposed for discocyclines from the Indian region. Only 18 of them are considered to be valid. The morphological features used for distinguishing these forms are listed and their distribution in different parts of this region is described. On the basis of the character of the megalospheric embryonic apparatus, size of the test and the thickness of the equatorial chamber layer they are arranged in three groups. The tentative phylogeny of these three closely related groups of forms is discussed.
A new genus of Polyzoa (Cryptostomata) from the Devonian of New South Wales, Australia
Authors: Wass Robin E. , Byrnes J. G.
Published: May 2009

Ignotrypa multivincula gen. et sp. nov., (Polyzoa, Cryptostomata), is described and figured from the Lower Devonian Garra and Nubrigyn Formations of central western New South Wales. It has a typical fenestrate meshwork but the carinae are thickened and joined laterally by numerous connections.
Formation of the Red Sea Depression
Authors: Whiteman A. J.
Published: May 2009

Various views have been expressed about the origin of the Red Sea Depression. Many earth scientists favour large-scale crustal separation and rotation of Arabia with respect to Africa—the paar theory; whereas a minority believe in a simple tensional origin. In the writer's view the almost “timeless” models presented by Drake & Girdler (1964) and Laughton (1966) are unacceptable because little of the available stratigraphic, structural and geo-morphological data was utilized in their construction. A tension system may have existed in the Red Sea area in late Pre-Cambrian and early Palaeozoic times. A depression existed in the northern part of the region in Carboniferous times and during Cretaceous times a tongue of Tethys occupied the northern and central portions of the depression. In Miocene times an extensive evaporite basin developed occupying most of the depression. The sill was situated in the Gulf of Suez Ayun Musa area.

The main and central troughs developed as a result of tension in Pliocene and later times. The Gulf of Aqaba Depression was formed by a fault system continuous with Dead Sea System which originated in (?) early Cretaceous times. The northern and central parts of the gulf were invaded by the sea in Pleistocene times.

The escarpments which bound the Red Sea Depression are in very few places fault or fault line scarps. Primarily they appear to be erosional features developed by pediplanation across the downwarped margins of the depression. In places, the shoulders and flanks were faulted later. In this way the uncon-formable nature of the contact, between the Mesozoic-Tertiary sediments and the Basement Complex (mainly Pre-Cambrian) which occurs at the foot of the escarpments, is best explained.
A gravity interpretation of the Liruei Younger Granite Ring Complex of Northern Nigeria
Authors: Ajakaiye Deborah E.
Published: May 2009

Gravity readings were taken on a 40-km traverse running roughly NE-SW across the Liruei Younger Granite ring complex of Nigeria. A negative Bouguer gravity anomaly of about 16 milligals amplitude was observed over the complex.

Electronic computing methods were used in the interpretation to obtain the best 2-dimensional and 3-dimensional structures which would fit the observed anomaly. The best computed models indicate that the contacts between the Liruei Complex and the surrounding Basement Complex dip outwards from the ring complex and, based on the surface density contrast of 0·10 gm/cc, the depth to the base of the density contrast is of the order of 7,500 metres.
Mineral layering in the Galway Granite, Connemara, Eire
Authors: Claxton Charles W.
Published: May 2009

Examples of semi-horizontal mineral layering in adamellites from the Galway Granite Batholith of Co. Galway, Eire, are described and illustrated. The layering results from variation in the amounts of the constituent minerals in successive horizons of the granite. It is suggested that the layering originated by settling of the early crystallizing minerals during quiescent periods in the emplacement of the granite, and that it may have been much more extensively developed than it is at present. Volatile constituents are thought to have reduced the viscosity of the magma periodically.
Soda-granites from South of Tatanagar, Bihar, India
Authors: Banerji A. K. , Talapatra A. K.
Published: May 2009

The nature and origin of some soda-granites from the western part of the Singhbhum shear zone, Bihar, India, are discussed. These soda-granites are responsible for copper sulphide, apatite-magnetite, and uraniferous mineralization within the shear zone. Earlier workers regarded these rocks as sheared materials representing a portion of the high sodic residual liquid from the neighbouring Singhbhum granite magma. The present work indicates that these rocks are migmatitic in nature and are the products of progressive replacement of pre-existing pelitic and semi-pelitic schists by felspathic materials. Migmatization is essentially post-shearing in age while the Singhbhum granite is pre-shearing in age. The migmatitic materials appear to have been derived by the partial melting of the Singhbhum granite during shearing, particularly in depth, as a result of sudden release of confining pressure consequent upon shearing and generation of heat caused by friction at the base of the shear zone. The resulting liquids, which were albite rich, found easy passage through the shear zone and brought about migmatization and mineralization in its wake.
A Model of the Structural Development of Israel and Adjacent Areas Since Upper Cretaceous Times
Authors: Freund Raphael
Published: May 2009

The rifting of the Red Sea, the folding of the Zagros-Taurus range (in Turkey and Iran), and the development of the structures in and near Israel appear to have resulted from a northward anti-clockwise rotational movement of Arabia, which occurred in several phases during Upper Cretaceous to Pleistocene times. The sinistral strike slip fault of the Dead Sea Fault system participated in this movement. It is hereby suggested that the fold and fault structures in Israel and adjacent areas are drag effects along this strike slip fault.
The Siluro-Devonian Boundary
Authors: Holland C. H.
Published: May 2009

The positioning of the Siluro-Devonian boundary is reviewed in the light of recent studies in both shelly and graptolitic facies in Europe and elsewhere. A case can be made for retaining the present position at the base of the Ludlow Bone Bed; but international opinion may demand a new standard section in the graptolitic facies, for example in Central Europe. In this event, it is suggested that a position at the base of the Monograptus uniformis Zone might prove the most widely satisfactory solution.
The Liassic Succession in a Clay Pit at Kirton in Lindsey, North Lincolnshire
Authors: Howarth M. K. , Rawson P. F.
Published: May 2009

A new clay pit at Kirton in Lindsey, Lincolnshire, gives continuous exposures of 21 feet of clays and limestone nodules of the davoei Zone at the top of the Lower Lias, 18 feet of similar beds and 8 feet of Marlstone Rock Bed belonging to the Middle Lias, and 38 feet of shales and limestones of the tenuicostatum and falciferum Zones of the Upper Lias. Liparoceratid, Amaltheid, Dactylioceratid and Hildoceratid ammonites occur and allow the zones to be delimited with some accuracy.
Origin of Ultrabasic and Basic Gneiss Masses in the Lewisian
Authors: O'Hara M. J.
Published: May 2009

It has been suggested that the ultrabasic and basic gneiss masses in the Lewisian near Scourie and Drumbeg are layered igneous bodies possibly containing primary igneous mineral assemblages. This hypothesis is reviewed in all its aspects and rejected on the grounds of field relationships, mineralogy, and geochemistry.
Significance of Punctae and Pustules in Brachiopods
Authors: Kemežys K. J.
Published: May 2009

A geometric model is proposed to explain the quincunx pattern of punctae which characterizes most terebratuloids. This model gives the two parametersdandg, which together express the density of punctae. The pattern of punctae in dalmanelloids does not differ in its basic geometry from that of the terebratuloids and can be defined by the same parameters. This also holds for the punctate spiriferoids and the punctate orthotetid genusStreptorhynchus. The pattern of pustules in the taleolate brachiopods differs from that of the model for the quincunx pattern of punctae, but can still be expressed in terms ofdandg. In this casedcorresponds to the wavelength of the costellae.

Both punctae and pustules are morphologically and numerically related to the marginal setae.
Undersaturated Potassic Lavas and Hypabyssal Intrusives in North Johore
Authors: Grubb P. L. C.
Published: May 2009

An interesting occurrence of highly potassic lavas and hypabyssal intrusives of assumed Tertiary age is described from North Johore. The thickest lava flow is gravitatively differentiated showing a basal horizon of potassic ankaramite and basanite grading up into highly potassic bolitized flow tops of leucite-tephrite composition. Evidently the parent magma was close to a biotite pyroxenite in composition and possibly an assimilation product of peridotite by granite.
The sub-surface shape of part of the Loch Ailsh Intrusion, Assynt, as deduced from magnetic anomalies across the contact, with a note on traverses across the Loch Borralan Complex
Authors: Parsons Ian
Published: May 2009

Local magnetic anomalies of large magnitude are found over the marginal ultrabasic rocks of the Loch Ailsh intrusion. An intrepretation of these anomalies based on the measured magnetic properties of the pyroxenites shows that they are not reconcilable with a low-angle structure as required by the hypothesis that the intrusion is a stratified laccolite, and suggests that they form a steeply dipping sheet at the syenite-limestone contact. Similar anomalies occur along the southern margin of the Loch Borralan complex, suggesting steeply dipping marginal ultrabasic rocks.
Zeolite Facies and Regional Rank of Bituminous Coals
Authors: Kisch Hanan J.
Published: May 2009

Diagnostic analcime-, heulandite-, and laumontite-bearing mineral assemblages from four areas in the Upper Carboniferous and the Permian of New South Wales have been correlated with the rank of the associated coals, represented by the carbon content of vitrinite. The coals are high-volatile bituminous to semi-anthracitic; their vitrinites contain from about 82 per cent up to an estimated 91 per cent carbon. Analcime-quartz is found associated with the lower-rank, the laumontite-rich assemblages with the higher-rank coals. Comparison with a similar correlation in Northern Yakutia (U.S.S.R.) indicates that diagnostic zeolites are not necessarily associated with coals of the same range of rank in different areas. Unlike the occurrence and stability range of burial metamorphic zeolitic assemblages, degree of coalification is probably independent of partial pressures of H2O and CO2: it is controlled mainly by maximum depth of burial, its duration, and the geothermal gradient.
Notes on cystoids
Authors: Paul C. R. C.
Published: May 2009

“Strobilocystites? kearsargensis Stauffer,” a supposed rhombiferan cystoid from the Kennett Formation, Kearsarge, California, is a diploporite cystoid tentatively assigned to Revalocystis Jaekel. This extends the stratigraphic range of the Dactylocystidae into the Silurian and is the first reported occurrence of Dactylocystidae from North America. An unusual specimen of Glansicystis baccata (Forbes) with IL1 represented by two small pentagonal plates is described. Glansicystis had four short ambulacra: I and IV have only one brachiole; II and V may have one to three brachioles.

An isolated echinoderm plate with structures which may represent pectinirhombs is described from the Whipple Cave Formation, Near Lund, Nevada. The structures differ from typical pectinirhombs and are older (Uppermost Cambrian or Basal Ordovician) than any previously described pectinirhombs.
Interglacial deposits at Wortwell, Norfolk
Authors: Sparks B. W. , West R. G.
Published: May 2009

Interglacial organic deposits, at Wortwell in Norfolk, containing bones of Elephas antiquus, plant remains and molluscs, are shown to be of Ipswichian age. The plant and molluscan assemblages of an early part of the interglacial and of the mixed oak forest zone are described and compared with similar assemblages from Ipswichian and Hoxnian deposits. The relation between this deposit and other local Pleistocene deposits in the Waveney Valley is discussed.
Some Nomenclatural Problems in the Inarticulate Brachiopods
Authors: Rowell A. J.
Published: May 2009

Five nomenclatural problems in the inarticulate brachiopods are discussed and solutions suggested for them. Two new genera, Eodinobolus, type species Obolellina magnifica Billings, 1872 and Orthisocrania, type species Pseudocrania divaricata M'Coy, 1851 are erected. Clistotrema nom. nov. for Orbicella d'Orbigny, 1847 non Orbicella Dana, 1846 is proposed.
Tonstein Bands in the Coalfields of the East Midlands
Authors: Eden R. A. , Elliot R. W. , Elliott R. E. , Young B. R.
Published: May 2009

Kaolinite-mudstone bands, widely recoginzed in the Carboniferous of Western Europe, where they are known as tonsteins, are also represented in Britain. On the basis of the probable correlation eight such bands have so far been found in the Coal Measures of the East Midlands. Laterally two of these bands are thought to pass into rocks intermediate in type between tonstein and more normal Coal Measures mudstones.
On the Age Relations of the Connemara Migmatites and the Galway Granite, West of Ireland
Authors: Leake B. E. , Leggo P. J.
Published: May 2009

Contrary to a previously published view, evidence is given to show that the Galway Granite is entirely later than both the quartzandesine migmatization and the potash-felspar migmatization in Connemara, and that the Oughterard Granite is probably earlier than the Galway Granite, not later. There is also strong evidence against regarding the foliated marginal granite of the north and north-east border of the Galway Granite as being different in origin from the marginal granite often found in the southern, western, and north-western borders. These results agree with the radio-chemical date of 365 m.y. determined for part of the Galway Granite.
Evolution of the Caledonides in the northern Trondheim region, Central Norway: a review
Authors: Roberts David , Springer Janet , Wolff Fr. Chr.
Published: May 2009

A résumé of the stratigraphy, sedimentation and volcanism of the Lower Palaeozoic rocks in the northern Trondheim region is presented. Spatially the Caledonian rocks occupy a shallow trough which plunges south-west. Within the trough the rocks have been subject to four episodes of deformation; the essential structure of the region is an anticline flanked by recumbent fold nappes (F1) which spill outwards on either side of the NE-trending spine. These are deformed by further major folds (F2). The F3 folds, developed widely but only on a mesoscopic scale, show a constant down-dip sense of overturning. It is thought that they were formed in response to gravitational sliding. F4 is represented only by local kink bands. It is probable that large areas of these Cambro-Silurian rocks are allochthonous, the marginal thrust being of late-F2 age. Examination of the structures is illuminating many other aspects of the geology of this segment of the Caledonian chain, making it possible to visualize the changing sequences of deformation, the relationship of metamorphism to tectonic level and the tectonic behaviour of domal granitic masses. In conclusion, comments are made on the relative significance of the orogenic ‘disturbances’ described from this part of Norway.
The Upper Eocene Brockenhurst Bed
Authors: Martini E.
Published: May 2009

Calcareous nannoplankton from the Brockenhurst Bed of Whitecliff Bay, Isle of Wight, belong to zone NP 20 of the standard Palaeogene calcareous nannoplankton zonation, indicating that the stratigraphic position of the Brockenhurst Bed is in the uppermost Eocene, and not equivalent to the type Lattorfian (Lower Oligocene).
Notes on the Triassic biostratigraphy of Svalbard
Authors: Tozer E. T. , Parker J. R.
Published: May 2009

A revised interpretation of the sequence of marine invertebrate faunas from the Svalbard Triassic is given. Correlations are made with the unusually complete sequence now recognized in Canada. The position of the faunas is given in terms of the recently proposed lithostratigraphic scheme. In the Lower Triassic, Griesbachian, Dienerian, Smithian and Spathian faunas are represented; in the Middle, Anisian and Ladinian. In the Upper Triassic only a small part of the Karnian is represented by a marine fauna. No new faunas are recorded but for the first time three ammonoid zones are discriminated within the Anisian.
Upward movement of granitic magma
Authors: Cann J. R.
Published: May 2009

The negative P-T slope of the wet melting curve of granite sets limits on the degree of upward movement of granitic magma formed at particular partial pressures of water vapour. Wet granite magma cannot rise very far from its place of formation, and only dry granite magma can be erupted as a liquid. This observation leads to a better understanding of the granitic structure of orogenic belts, and explains some of the apparently paradoxical aspects of granites. Other wet magmas would also not be expected to be erupted as liquids.
Palaeogene warping in the Isle of Wight
Authors: Daley B. , Edwards N.
Published: May 2009

Gentle folding or warping, of Lower Oligocene age, pre-dating the main post-Hamstead Beds folding, is indicated where the Bembridge Marls rest unconformably on eroded Bembridge Limestone. The folding appears to have been along generally NW–SE trending axes. This trend is compatible with penecontemporaneous and even earlier folding in Southern England and adjacent parts of north-western Europe. In Southern England, the main folding may have been earlier than the Miocene age generally accepted.
Intra-Lower Palaeozoic faults in the Southern Irish Sea Area
Authors: Baker J. W.
Published: May 2009

The deep-seated caledonoid lineaments which developed in conjunction with the L. Palaeozoic basins in Wales, S. Irish Sea and Co. Wexford, bounded elongated fault-blocks within the resistant basement and its cover; it is suggested that under compression these broke internally along contemporary, strike-slip cross-faults. In the Central Wales and N. Wales–SE Co.Wexford blocks the latter were principally E–W and N–S faults respectively. Repeated movements of diverse styles along members of all three suites have influenced sedimentalogic, volcanic, plutonic and geomorphologic events throughout the Phanerozoic; in particular, they permitted the Irish Sea Geanticline to rise above the roots of the Monian tectogene, and determined the form of the younger Irish Sea sedimentary basins.
Hydrothermal Alteration in the Carrock Fell Area, Cumberland, England
Authors: Ewart A.
Published: May 2009

Within this area are developed a series of quartz veins which cut three rock types, the Grainsgill granite, part of the southern margin of the Carrock Fell gabbro to the north, and an intervening area of hornfels belonging to the Skiddaw Slate Series. Both the hornfels and the gabbro have suffered thermal metamorphism due to the granite, and in addition, the hornfels has undergone a very localized metamorphism due to the gabbro. All three rock types have undergone a further hydrothermal alteration due to the quartz veins. The microscopic changes involved in this alteration are described and it is shown that the end product in each case is essentially similar to a greisen, with the addition of pyrite and arsenopyrite.
A Conglomeratic Grit at Knowle Wood, near Woolley, South Devon
Authors: Blyth F. G. H. , Shearman D. J.
Published: May 2009

An outcrop of siliceous, conglomeratic grit is described on the margin of the Dartmoor granite near Woolley, and is considered to be probably of Oligocene age.