bluuebunny/crossref_metadata_2025 huggingface dataset:
Granite beneath Viséan sediments with mineralization at Rookhope, northern Pennines
Authors: DUNHAM KINGSLEY CHARLES , DUNHAM ANSEL CHARLES , HODGE BRIAN LESLIE , JOHNSON GEORGE ANTHONY LOBJOIT
Published: October 2009

The geological results of a borehole drilled to investigate the coincidence of centres of a zonal pattern of mineralization (
Dunham 1934
) with areas of strong negative Bouguer anomaly are presented. The presence of a granite batholith with cupolas, postulated by Bott & Masson-Smith (1957) has been proved; the top surface of the granite was found at 1281ft depth and the boring was continued to 2650 ft in granite.

The section begins in the Great Limestone at the base of the Namurian; a normal succession in the Middle Limestone Group (Lower Carboniferous) is revealed, the Smiddy Limestone with
Girvanella
Band being reached at 1056 ft 6in. The Lower Limestone Group differs from the section in Teesdale and the Pennine escarpment; in particular, beds equivalent to the Melmerby Scar Limestone, identified by their fauna of algae, corals, and brachiopods, have a rubbly lithology and are split by bands of seatearth, sandstone, and shale. Beneath them, clastic sediments 38 ft thick with marine fossils rest on the weathered surface of the granite.

Two quartz-dolerite sheets were proved; the Little Whin sill, 6ft, is in the Three Yard Limestone as at Stanhope, while the Great Whin sill, 192ft 9in, lies beneath the Jew Limestone, stratigraphically lower than in Upper Weardale.

The Weardale granite, carrying biotite and abundant muscovite, has a low-dipping foliation in the upper part, but this becomes less obvious below 2225ft depth. Preliminary X-ray studies indicate that low albite, orthoclase, maximum microcline, and forms intermediate between the last two are present. Analyses of representative rocks for major and trace elements are given. Xenoliths are conspicuously absent, but aplites and pegmatites are common. The mineralogical and chemical effects of weathering before Carboniferous sedimentation, and of the mineralization, are described.

The borehole was sited near the crossing of the Boltsburn lead vein
(ene-wsw)
and the Red fluorite-iron vein
(ese-wnw),
both of which dip towards it. Strong metasomatic mineralization, including green fluorite, blende, and quartz occurs in the Tynebottom, Jew, and Lower Little limestones. Numerous small veins were also cut both in the sediments and the granite. Though chalcopyrite is present against the lower sediments, there is no evidence of a concentrated copper zone. Fluorite continues into the granite, and pyrrhotine, not present above, is found from 1355 ft depth. Mineralization continues to much greater depths than have previously been proved in the area; its source presumably lies beneath the granite cupolas, which may, however, have guided the rising fluids.
Normal faulting in British Pleistocene deposits
Authors: SHOTTON FREDERICK WILLIAM
Published: October 2009

Examples of normal faulting affecting Pleistocene deposits of Gipping (Riss) age are described and discussed. It is concluded that small-scale trough-faulting at Stretton on Fosse, Warwickshire, is due to tension induced by cooling of frozen ground in winter. Largerscale faulting has been temporarily exposed in motorway cuttings near Kilsby, Northamptonshire, and near Narborough, Leicestershire. The faults resemble those at Stretton, but are more widely spaced, have much larger throws, and lack associated minor faults. This largerscale faulting is interpreted in terms of reactivation of earlier fractures as a result of updoming due to isostatic recovery after retreat of the ice. There is some correlation in trend-direction between the Pleistocene faults and the post-Triassic faults in the Pre-Cambrian rocks of Charnwood Forest. The fault-movements appear to have been completed shortly after the Gipping Glaciation. Comparable faulting in the Netherlands and Germany and a few possibly similar cases in Britain are mentioned.
A preliminary magnetic survey of the Western Approaches to the English Channel
Authors: HILL MAURICE NEVILLE , VINE FREDERICK JOHN
Published: October 2009

A preliminary magnetic survey of the Western Approaches to the English Channel reveals a marked wsw-
ene
lineation of the anomalies. This is considered to reflect the relief of the metamorphic and igneous basement, which in turn delineates an Hercynian structural trend. Variations in the amplitudes of individual anomalies are probably due largely to the variety of rock-types within the basement rather than to large-scale variations in its topography. It is suggested that the Cornubian batholith and the outcrops of basement material in the Lizard and Start Point districts are related to the structural accommodation of the change in the Hercynian trend direction in the south-west peninsula.

The possible extension of the anomaly pattern over the continental shelf edge points to the need for further surveying over the continental rise off the Western Approaches, and over the Grand Banks off Newfoundland, in order to test current ideas on the nature of the continental margin.
Isotopic age-determinations of rocks from the British Isles, 1955–64
Authors: SABINE PETER AUBREY , WATSON JANET VIDA
Published: October 2009

Over 475 individual age-determinations of British rocks, recorded in some sixty papers, have appeared during 1955–64, the decade in which isotopic dating reached practical maturity and began to have great effect in establishing the scale of events in historical geology, including that of the Pre-Cambrian. The willing co-operation of all the British laboratories in which isotopic ages are determined has enabled abstracts of these papers to be prepared for publication; the emphasis of the abstracts lies in the geological implications.

In an introductory section (by P. A. Sabine& J. Watson), the number of determinations of British rocks is plotted against apparent ages. The resulting histograms are broadly similar to those derived from world-wide sources and from other countries, showing that they record not only the incidence of laboratory determinations but fundamentally significant geological events. Major peaks of activity are indicated, the implications of which are reviewed. Periods of plutonic activity are shown in the Lewisian at 2600 to 2200m.y. (Scourian) and 1600 to 1450m.y. (Laxfordian). Metamorphic rocks, migmatites, and granites from the Caledonian Belt are spread from about 750 to 360 m.y. with a weak maximum at 750 to 650 m.y. and a stronger one at 450 to 360 m.y. In south-west England metamorphic activity yields dates from 400 to 350m.y., and Hercynian granites dates from 300 to 250 m.y. Tertiary granites and allied rocks are mainly 65 to 50 m.y. old.

In each abstract an attempt is made to include geographical locality, character and geological relationships of specimens investigated, method employed, and constants used, ages obtained, and conclusions drawn. Full indexes are provided.
Intrusive tuffs of west Cork, Ireland
Authors: COE KENNETH
Published: October 2009

Minor intrusions in west Cork include pipes and dykes believed to have originated by a process of fluidization. These bodies are described, emphasis being placed on features known to be characteristic of fluidization. The intrusions are pipes or dykes with sharp contacts with the country-rock, which plunge vertically or at high angles. Some show a zonal form based on the xenolith content; xenoliths moved upwards in the central zones but there is evidence of downward movement in some of the outer zones. Matrices are devoid of igneous material. The west Cork bodies are distinctive in occurring between phases of deformation of a fold-belt and in having their positions controlled by pre-existing structures. Petrologically they are distinguished by having a carbonate content that is variable but attains a maximum of 95 per cent.

The bodies are compared with certain carbonatites that are held to be high-level developments of kimberlite pipes.
Clay fractions and colours of some Devonian red beds in the Catskill Mountains, U.S.A
Authors: FRIEND PETER FURNEAUX
Published: October 2009

The fine fractions of samples from a cyclothemic section in the Catskill facies, Appalachian region, have been analysed by X-ray diffraction and determinations of iron content made. All the samples contain both illite and chlorite, and some contain kaolinite. Two of the cyclothems are richer throughout in kaolinite. This is attributed to a change in provenance and demonstrates the relative unimportance of diagenetic alteration of the clays.

The redness is due to the presence of fine-grained hematite, much of it in hexagonal crystalline form. The clay content does not vary with the red or non-red state of the rocks, and this colour differentiation did not therefore involve alteration of the clays. A hypothesis to explain the red-non-red differentiation within the cyclothems is put forward.
Modern concepts of the structure and development of the structure and development of the Earth’s crust and the upper mantle of continents
Authors: BELOUSOV VLADIMIR VLADIMIROVICH
Published: October 2009

In recent years geological concepts of the structure, history, and development of the Earth’s crust have been rapidly modified in the light of new geophysical and geochemical data. It is now possible to formulate with greater precision the problem of the inter-relationships between geological structure and geological processes observed at the surface on the one hand, and the deep structure of the crust and upper mantle on the other hand.
Erosion-surfaces, tectonics and volcanic activity in Uganda
Authors: BISHOP WALTER WILLIAM , TRENDALL ALEC FRANCIS
Published: October 2009

The historical development of the erosion-surface nomenclature previously used in Uganda is reviewed briefly. Several surfaces are defined, or re-defined, and together with their component physiographic units are described and given local names referring to areas in eastern and central Uganda.

For eastern Uganda the sub-volcanic (broadly early Miocene) topography is reconstructed in detail and its subsequent modification is described. In central Uganda two major erosion-surfaces are recognized. Post-formational amendments to these former landscapes are discussed in relation to the present drainage-pattern and to tectonic deformation associated with the development of the Lake Albert-Edward graben. The stratigraphical-geomorphological history of the Western Rift south of the Murchison Falls is summarized.

Sequences of events in the formation of the present landscape are outlined for eastern, central and western Uganda, and extrapolation is made from the eastern region into adjacent areas of Kenya. Some recasting of established sequences is suggested. It is concluded that insufficient attention has been paid previously to the local physiographic setting (often dominated by the form of the sub-volcanic landscape) controlling the stratigraphical relations and lithology of the fossiliferous Miocene volcanic and other sediments. The extent of late Tertiary and Quaternary tectonic deformation of erosion-surfaces has in the past been underestimated.
The structural development of the Gulf of Alaska sedimentary province in southern Alaska
Authors: STONELEY ROBERT
Published: October 2009

The Mesozoic and Cainozoic beds of the Gulf of Alaska sedimentary province were deposited respectively in an active trough and on a rapidly subsiding shelf at the Pacific margin of the North American continent. They have been deformed by repeated oceanwards thrusting and folding, which decrease in intensity towards the ocean away from a currently active dextral strike-slip fault at the inner edge of the basin: it is estimated that a lateral shortening of the order of 10 miles in the Cainozoic sediments alone is represented by this thrusting. The processes whereby these structures could have developed are examined: it is concluded that they have resulted essentially from a continuous movement of the Pacific Ocean floor relatively towards, and perhaps underneath, the continental margin, with two culminations of intensity during which the sedimentary layers above were stripped off and thrust back towards the ocean. This movement took place simultaneously with an independent dextral displacement on the bounding strike-slip fault-system, which may have contributed to the lateral shortening in the sedimentary province to the south and was at least strong enough to influence the strike-directions of the late Cainozoic structures.
The Pleistocene deposits of the Isles of Scilly
Authors: MITCHELL GEORGE FRANCIS , ORME ANTONY RONALD
Published: October 2009

The paper establishes the presence of a till and an outwash gravel (both containing far-travelled erratics and heavy minerals) along the northern margin of the Scilly Isles. The glacial deposits rest on a Lower Head, raised beach and shore platform, and are overlain by a younger beach and an Upper Head. The sequence is compared with similar deposits in the south of England and of Ireland, and a Gipping age is claimed for the glacial deposits.
Aegirine-gneisses in central Malawi
Authors: BLOOMFIELD KEITH
Published: October 2009

A sixty-mile-long zone of interbanded psammites and aegirine-gneisses occurs within the paragneisses of the Mozambique belt in central Malawi at about the 13°30's parallel. The typical mineral assemblages are quartz-micro-cline-oligoclase/andesine-magnetite-zircon and aegirine-(Na amphibole)-quartz-microcline-oli-oclase/andesine-zircon-magnetite. Two chemical analyses show that the Fe/Mg ratios are very high and that Ca is present in only small amounts.

A syngenetic origin from glauconite-rich feldspathic sandstones is suggested, the sedimentary environment being near-shore deltaic or marine.
Gravity and magnetic surveys of the younger gabbros of Aberdeenshire
Authors: McGREGOR DAVID MARSHALL , WILSON CHARLES DOUGLAS VERNON
Published: October 2009

About 700 gravity and 1200 magnetic measurements have been made in north-east Aberdeenshire in order to find the attitudes of the basic intrusions. The surveys have covered the younger gabbros, the Bennachie granite and the intervening areas. A marine magnetic survey has covered an area about 40 × 30 km offshore from Banff.

The Bouguer anomalies are positive over almost the whole area except the Bennachie granite; together with prominent magnetic anomalies these indicate that the exposed gabbros form part of a continuous basic sheet. This sheet varies in thickness from 1 or 2 km near Huntly to 7 km at Cabrach.

Positive magnetic and negative gravity anomalies are found from Dufftown to the Moray Firth, suggesting that there are extensive granite intrusions in this area. Hidden extensions of the Cabrach mass and the Bennachie granite have been approximately delineated. Positive gravity anomalies extend from Cabrach over the northern part of the Morven mass.

Models have been constructed which fit the anomalies over the Insch and Belhelvie masses; these suggest that there has been post-consolidation folding at Belhelvie.

In five localities the gravity and magnetic anomalies are closely correlated and the direction of magnetization has been computed for each of these areas. These are compared with the directions found by Blundell & Read (1958) and the deformation of the basic intrusions is discussed. Gravity and magnetic anomalies at the east end of the Insch mass suggest that this mass also has been deformed.
Some observations on burrows of thalassinidean Crustacea in chalk hardgrounds
Authors: BROMLEY RICHARD GRANVILLE
Published: October 2009

Upper Cretaceous Chalk hardgrounds (horizons of early-diagenetic cementation beneath intraformational erosion surfaces) characteristically contain extensive, branching systems of burrows. The morphology of these burrows is described and compared with that of the ichnogenus
Thalassinoides
Ehrenberg. They were constructed before the sea-floor was cemented, and are attributed to sediment-feeding crustaceans similar to the living
Callianassa.
The burrows remained occupied after the sea-floor sediment was cemented. This may be explained either by a change in feeding-habits of the burrower, or by the occupation of the burrow by another crustacean which fed by plankton-straining or predation. The existence of burrows comparable to those in hard-grounds, throughout much of the White Chalk, is evinced by (i) the appearance of burrows at sedimentary junctions where a change of colour takes place; (2) the common occurrence of burrow-shaped flint nodules; and (3) the development of ‘nodular chalk’.
The Wenlock and Ludlow succession in the Howgill Fells (north-west Yorkshire and Westmoreland)
Authors: RICKARDS RICHARD BARRIE
Published: October 2009

Eleven zones, based upon sixty graptolite species and subspecies, are defined in the Wenlock and Ludlow series of the Howgill Fells. Good stream sections enable accurate zonal thicknesses to be given in several cases, and correlation with other regions is attempted. Two new graptolites are described.
Geological sciences in the world scientific community
Authors: HARRISON JAMES MERRIT
Published: October 2009

T
his
is the second time in three years that you have honoured a Canadian by inviting him to present the William Smith Lecture. From this I conclude that Tuzo Wilson gave you such a stimulating and enthusiastic address that you felt that perhaps another Canadian might be able to do the same. I hope, at the end, you will feel that the reasoning was sound. I warn you, however, that I shall make no attempt to emulate what he has done. Wilson, Gilluly, Størmer, and other distinguished William Smith Lecturers gave you reviews of some of the stimulating international scientific developments in geological sciences, whereas I propose to deal rather with some of the more bureaucratic relationships, which, of course, help the scientific domain to develop. After all, I am a professional bureaucrat!

Because William Smith prepared the first reasonable geological map, I take it that the geological map is considered fundamental by the Geological Society. Certainly, I consider a geological map as fundamental for geological science. Without it geology cannot exist, but because of it geology has encountered 150 years of difficulties. To be most useful a geological map must be an expression of carefully thought out conclusions based on examinations made by a field geologist, supplemented by whatever laboratory improvements can be provided, and whatever philosophical speculation he may find necessary to include on the map. This highly subjective result of his activities looks like a completely objective portrayal of facts as they exist, and hence the controversy.
The Kilonwa syenite, Tanzania
Authors: KEMPE DAVID RONALD CHARLES
Published: October 2009

The sheared Kilonwa aegirine-arfvedsonitebiotite syenite, central Tanzania, is described, with three analyses and some mineralogical data. The syenite is compared with aegirine-granulites, -schists and -gneisses, from various localities, to which are ascribed metamorphic or metasomatic origins. The Kilonwa rocks, however, are considered to be of igneous parentage, forming an example of the small syenitic masses to be found in highly metamorphosed Pre-Cambrian terrains
Pleistocene deposits of the north-western Allegheny Plateau, U.S.A
Authors: WHITE GEORGE WILLARD
Published: October 2009

In North America Pleistocene ice sheets entered the lowland now occupied in part by Lake Erie and expanded far southward in several lobes in the Interior Plains, but less far in two lobes in the Allegheny Plateau to the east in north-eastern Ohio, north-western Pennsylvania and western New York. This maturely dissected plateau, composed of essentially horizontal Carboniferous strata, has a summit level ranging from about 1200 ft in the west to about 1800 ft in the east.

In recent years excavations as deep as 135 ft for strip mines (coal), highways and quarries (limestone) in that part of the plateau in Ohio and Pennsylvania have exposed complete sections as much as a mile in length, which reveal lower drifts, mainly till, that have been previously almost unknown. Each till sheet has a characteristic texture and mineral composition and separate sheets can be traced for more than 100 miles, and treated as rock stratigraphical units. The younger tills are much higher in clay than the older tills. The feldspar content of the sand fraction ranges from about 5 per cent in the oldest till to 30 per cent in the youngest till. Carbonates range from less than one per cent in the oldest till to about 15 per cent in the youngest.

Within each till sheet there is a decrease in feldspar and an increase in quartz toward the margin. Statistical studies, in part by trend-surface analysis by computer methods, confirm the regularity of this variation, which is ascribed to dilution by local feldspar-poor sandstone. The dilution is much greater in the older tills; at their margins 90 per cent of the quartz content may be locally derived.

The lowest till, of pre-Illinoian age, entirely a sub-surface unit, is everywhere thoroughly weathered. The overlying till of probable Illinoian age, consists of two sheets, the upper one of which has a thick palaeosol. The bulk of the drift is early Wisconsinan in age and consists of three or more till sheets. It is named (in Pennsylvania) the Titusville Till and has a
14
C age of about 40 000 years. It is sandy, very compact and oxidizes to a distinct olive-brown colour. The weathering on it is not as intense as that of the two lower tills. The oldest till of late Wisconsinan age, the Kent Till, is a distinctive coarse yellow-brown, sandy till. It is overlain by the chocolate-brown, silty, more highly calcareous Lavery Till, which in turn is overlain by the brown, silty-clayey Hiram Till.

Each of the older tills, except the pre-Illinoian, extends farther south and south-east than the later tills, so that each forms the surface drift in a belt, ranging from 2 to 20 miles in width, in which its surface morphology and soil characteristics can be studied and its general character compared with that in the sub-surface.
Geosynclinal theory and the organizational pattern of the North-west Borneo Geosyncline
Authors: HAILE NEVILLE SEYMOUR
Published: October 2009

The North-west Borneo Geosyncline occupied most of Sarawak, Brunei and western Sabah, extending over a distance of about 800 km in a ne–sw direction. The very thick sequence of strata deposited in the geosyncline ranges in age from late Cretaceous to late Cainozoic; over thirty formations have been defined and these may be classified into four groups:

(i) Rajang Group (late Cretaceous to early Miocene): thick intensely folded typical flysch with chert-ophiolite at or near the base.

(ii) Baram Group (late Eocene to late Miocene): predominantly argillaceous, with some sandstones and thick limestones.

(iii) Plateau Group (late Cretaceous to? Miocene): thick molasse-type continental deposits in the south.

(iv) Brunei Group (Oligocene to Recent): estuarine and marine deposits with molasse affinities in the north.

Previous syntheses have regarded western Borneo, lying to the south, as the probable foreland, but the author seeks to show that this region acted as a eugeanticlinal ridge and intermediate hinterland. The main eugeosynclinal furrow occupied the present outcrop of the Rajang Group, whereas the later miogeosynclinal furrow lay further north; a submerged miogeanticlinal ridge, not so clearly defined, separated the furrows. The Baram Group was deposited mainly in the miogeosynclinal furrow. A marked dynamic polarity is shown by migration of flysch deposition, orogeny, and molasse deposition, from south to north across the geosyncline; these processes also seem to have migrated along the geosyncline from west to east and north-east.

The distribution of the main chert-ophiolite belt along the internal side of the eugeosynclinal furrow and of the late-geosynclinal and post-geosynclinal lavas and acid intrusions in western Sarawak and western Kalimantan follows the typical pattern, with some minor exceptions. A terminal volcanic phase is represented by late Cainozoic lavas on the eugeosynclinal deposits.
Five boreholes in Shropshire and the relationships of shelly and graptolitic facies in the Lower Silurian
Authors: COCKS LEONARD ROBERT MORRISON , RICKARDS RICHARD BARRIE
Published: October 2009

The shelly Lower Silurian in the classic area of Shropshire is correlated with the graptolite zones erected in Central Wales and the Southern Uplands of Scotland. Middle Llandovery rocks (previously unrecognized in the Welsh Borderland) are proved and the complete sequence of Upper Llandovery zones is probably present. In the Wenlock the two basal zones,
centrifugus
and
murchisoni,
are unproven in the boreholes and part at least of the succeeding
riccartonensis
Zone is also missing. The Middle Wenlock is complete.

The shelly communities in the Llandovery show a complete sequence from a basal shallowest-water
Lingula
community to a deepest-water
Clorinda
community at the top. Above the latter, west of the Longmynd spur, is defined a ‘Marginal’
Clorinda
community, with many usual elements absent.

Other records of graptolites from the Shropshire Lower Silurian are re-assessed. The age of the lowest Wenlock Buildwas Beds (and hence the true position of the base of the Wenlock in the graptolite sequence) remains open, but the boundary is probably correctly placed at the bottom of the
centrifugus
Zone.
The stratigraphy and structure of part of west Finistère, France
Authors: BISHOP ARTHUR CLIVE , BRADSHAW JOHN DUDLEY , RENOUF JOHN THOMAS , TAYLOR ROGER THOMAS
Published: October 2009

The area described includes the Plougastel and Crozon peninsulas and the south-west Pays de Léon. There are two distinct rock sequences: Pre-Cambrian Brioverian greywackes and their metamorphic equivalents, overlain unconformably by Lower Palaeozoic and Devonian shelf sediments.

The Brioverian sediments were folded and metamorphosed during the late Pre-Cambrian Cadomian orogeny. The main folding occurred before the emplacement of the Gneiss de Brest granodiorite (previously regarded as granitized Brioverian) and impressed on the area an
ene–wsw
axial-plane cleavage. There followed regional metamorphism that reached almandine amphibolite grade.

After peneplanation, Lower Ordovician seas transgressed northwards across the area and subsequently sedimentation continued, though with breaks, until Middle Devonian times. Posthumous movement on
ene–wsw
Cadomian structures influenced sedimentation from time to time. A shelf sea stretched southwards to Iberia and was bounded immediately to the north of the area studied by a land mass whose northern limit is unknown.

Variscan movements threw the Palaeozoic sediments into asymmetrical folds with trends parallel to the
ene–wsw
Cadomian structures whilst the underlying Brioverian rocks deformed largely by shearing on pre-existing planes. Along the Elorn Valley Variscan folding and faulting combined to produce a major dislocation zone that separates the dominantly crystalline Pays de Léon from the Palaeozoic sedimentary area to the south.

The
ene–wsw
structural trend of western Brittany is of Pre-Cambrian initiation. Structures of similar trend in the English Channel may well have been initiated at the same time.
Structural geology of the Malvern, Abberley and Ledbury hills
Authors: PHIPPS COLIN BARRY , REEVE FREDERICK ARTHUR EDWARD
Published: October 2009

The geological structure of the Malvern, Abberley and Ledbury Hills is described in detail. The apparently anomalous association of high- and low-angle reverse faults, vertical faults, high- and low-angle normal faults, wrench faults and isoclinal folding is interpreted as the result of upthrust tectonics related to the differential movement of basement blocks. The western boundary of the Pre-Cambrian outcrop appears to be the outcrop of an upthrust fault, with downthrow to the west, and with a vertical separation as large as 4000 ft. Upthrust faults are characterized by a strongly curved profile, and their geometry is a function of the tectonic level at which they are viewed. The curved fault-planes can be shown to plunge in such a manner that highly complex outcrop patterns emerge. The mechanics of plunging upthrust faults are discussed. All folding adjacent to the major Malvern upthrusts appears to be related to them and important variations in the type and intensity of folding can be discerned in vertical sequence. The Ledbury and Mathon folds appear to have originated as the result of major sinistral wrench movement along the Ledbury and Colwall faults respectively. The eastern boundary of the Pre-Cambrian and Palaeozoic rocks appears to be a fault in most areas, but it is unlikely that it anywhere has a vertical separation in excess of 1000 ft. The presence of the deep Worcestershire basin immediately to the east of the Pre-Cambrian outcrop suggests the existence of a major upthrust fault with downthrow to the east, now covered by Mesozoic sediments. This fault, together with the upthrust fault which forms the western boundary of the Pre-Cambrian outcrop, would have defined the Malvern horst during late Palaeozoic times.
The structure and stratigraphy of the Dalradian rocks of north Achill Island, County Mayo, Ireland
Authors: KENNEDY MICHAEL JOHN
Published: October 2009

Achill Island is underlain by a mixed suite of low-grade metamorphic rocks. The lithological units of the northern part, the subject of this paper, are systematically described. The deformation history can be divided into five separate phases. The first phase,
D
1, produced isoclinal
F
1 folds and
S
1 flattening schistosity in mica schists; and an
L
-tectonite fabric associated with some tight
F
1 folds in psammitic rocks. The second phase,
D
2, produced tight to isoclinal reclined
F
2 folds and
S
2 strain-slip schistosity in mica schists; and
S
2 flattening schistosity or an
L–S
fabric in psammitic rocks. This was followed by the third phase,
D
3, which produced tight to close upright folds and
S
3 strain-slip schistosity. The folds formed during these phases plunge gently between north-east and south-east. This variation in the trend of the plunge is the result of open
F
4 refolding. Finally, the latest deformation,
D
5, resulted in the development of kink bands. Three tectonic slides, of
D
1 age, are recognized in the area, one of which separates rocks of two separate stratigraphical successions. This slide can be mapped around the major southward-facing
F
2, folds of the area. One large dextral strike-slip fault is present. The two stratigraphical successions are compared with the Scottish Dalradian; one with the Islay Succession, and the other with the Moine Series. In North Achill large-scale
F
2 folding places the equivalents of the Moine Series structurally above the Islay succession in the core of an
F
2. anticline.
The age of the Vindhyan System of Peninsular India
Authors: CRAWFORD ARTHUR RAYMOND , COMPSTON WILLIAM
Published: October 2009

New isotopic data, mainly Rb–Sr, are given for the Vindhyan System of Peninsular India, the underlying Gwalior Series and Bijawar Series, and a pipe of kimberlitic affinities which intrudes the Upper Vindhyan. The Vindhyan System is shown to have a base with an age of at least 1200 and possibly 1400 m.y. The Gwalior Series is shown to have an age of between 1600 and 2000 m.y. while the Bijawar Series is very much older at about 2500 m.y. The necessity for revision of palaeomagnetic interpretations based on very different age estimates is shown, and it is recommended that because of its probable long time span any evidence for glaciation in the Vindhyan, at present poor, needs to be carefully attributed stratigraphically.
The geology of Socotra Island, Gulf of Aden
Authors: BEYDOUN ZIAD RAFIQ , BICHAN HERBERT ROY
Published: October 2009

Basement rocks crop out in three main uplift areas; elsewhere they are overlain by a veneer of Cretaceous and Tertiary plateau limestones. The oldest basement rocks are amphibolite facies meta-sediments and meta-igneous rocks which have been intruded by synkinematic granites and late-kinematic gabbros; younger weakly metamorphosed tuffs and mudstones also occur. Post-kinematic igneous activity gave rise to a sequence of volcanic rocks, hornblende/biotite and peralkaline granites, gabbros and minor intrusions which make up the bulk of the Haggier mountains. Of these the large occurrence of peralkaline granites is considered in detail. Following a long period of basement peneplanation, sediments were deposited which consist of Lower and Middle Cretaceous limestones, with some basal sandstones, followed without apparent break by cliff-forming shelf limestones of Palaeocene-Eocene age. Oligo-Miocene chalky deposits are only preserved in structural depressions. Vertical movements were predominantly responsible for the structure which is simple in the east but dissected by
wnw–ese
block faulting in the west. Correlation with southern Arabia and Somalia suggests that the basement metamorphic association is Pre-Cambrian and the post-kinematic igneous rocks are early Palaeozoic; the sedimentary formations broadly correlate with those of southern Arabia and the Oligo-Miocene deposits in particular are most closely related to those of Dhufar.
A gravity survey of a region of the Highland Boundary Fault in Scotland
Authors: QURESHI IFTIKHAR RASUL
Published: October 2009

The results of 1591 gravity measurements made in parts of the Midland Valley and the Grampian Highlands of Scotland, flanking the Highland Boundary Fault-zone between Callander and Cowal are described and density units in the Palaeozoic rocks of the area distinguished on the basis of some 800 laboratory measurements.

Steep gravity gradients across the Highland Boundary Fault at Callander and Aberfoyle show that its small hade to the north-west, observed at surface, is maintained to a depth of 2400 ft below sea-level, indicating that the fault behaved as a high-angle reversed fault in mid-Devonian times. West of Loch Lomond, the fault continues in general alignment with its course to the east and is inferred to underlie the Carboniferous cover in the Greenock–Inverkip region.

The existence of a deep sedimentary basin bounded to the north-west by three step faults and to the south-east by the Highland Boundary Fault is revealed by a gravity low west of Loch Lomond. The basin is probably partly filled by Lower Old Red Sandstone.

The maximum thickness of the Lower Old Red Sandstone sediments in the surveyed area is between 5000 and 6000 ft and the formation thins south-eastwards in the region of the Ochil Fault.

On the flanks of the Highland Boundary Fault, the survey has provided information of regional importance: the slate-belt probably occupies a downfolded synform within the Dalradian rocks; the Ochil Fault can have only a small magnitude in the surveyed area; the maximum thickness of the Lower Old Red Sandstone sediments in the area is between 5000 and 6000 ft and the formation thins south-eastwards in the region of the Ochil Fault.
Chemical data from the Malvernian of the Malvern Hills, Herefordshire
Authors: BLYTH FRANCIS GEORGE HENRY , LAMBERT RICHARD ST JOHN
Published: October 2009

This account, prepared from Dr A. Brammall's notebooks, presents thirty-six analyses of Malvernian rocks and eleven analyses of their constituent minerals, together with a statement of Brammall's views on the metasomatic changes affecting the epidiorite group.
The first Lower Palaeozoic fauna proved from South Africa
Authors: COCKS LEONARD ROBERT MORRISON , BRUNTON CHARLES HOWARD CAMPBELL , ROWELL ALBERT JOHN , RUST IZAK CORNELIS
Published: October 2009

A fauna is described from the Cedarberg Formation of the Table Mountain Group, western Cape Province. New taxa of brachiopods are
Trematis taljaardi
sp. nov.,
Marklandella africana
sp. nov.,
Eostropheodonta discumbata
sp. nov., and
Plectothyrella haughtoni
sp. nov. These indicate an age close to the Ordivician–Silurian boundary. This is the first Lower Palaeozoic fauna to be found in Africa south of the Sahara.
Stratigraphical correlation of the Triassic rocks of the British Isles
Authors: AUDLEY-CHARLES MICHAEL GEOFFREY
Published: October 2009

Traditional ideas of the stratigraphical correlation of the British Triassic rocks are reviewed briefly. A revised scheme of stratigraphical correlation is proposed, mainly on the basis of sub-surface information from borings made after 1940. Six principal lithostratigraphical divisions are tentatively proposed. The base of the Bunter Pebble Beds is taken as the base of the Trias, and the top of the Rhaetic is considered to be the top of the Trias. The principal elements in this correlation are the recognition of two major lithostratigraphical units in the Keuper Marl, the recognition of the usefulness and widespread extent of the Waterstones Formation, and the re-interpretation of many borelogs of 'Bunter Sandstone' in terms of two lithostratigraphical units. The stratigraphical correlations suggested in this paper have important implications for the study of the palaeogeography of the Triassic period in Britain.
The Triassic salt deposits of north-western England
Authors: EVANS WYNDHAM BOWEN
Published: October 2009

A brief account is given of the present state of knowledge regarding the stratigraphy of the salt-fields in north-western England. It is stressed that salt solution has taken place on a considerable scale, and that old and shallow provings can be most misleading.

Interpretations of the British Keuper as a desertic continental deposit have been based largely on condensed non-saliferous sequences. In contrast the evidence in the salt-fields is capable of being interpreted differently. It is contended (i) that the clastic and chemical rocks of the salt-fields were deposited beneath water; (ii) that this water is likely to have been deep; (iii) that it was in continuous contact with the open ocean across a shallow shelf area occupying much of west-central Europe.

It is further contended that the importance of local factors in each salt basin so outweighed that of surface climatic fluctuations that it is unwise to assume that a particular salt formation in a particular basin necessarily correlates with a salt formation in another basin. Consequently it is argued that, away from the shelf-areas, no sound basis yet exists for long-range lithological correlations of the British Keuper.
Problems of Rhaetian stratigraphy with special reference to the lower boundary of the stage
Authors: PEARSON DAVID AMORY BAPTY
Published: October 2009

The use of ‘Rhaetic’ as an international lithostratigraphical term is rejected in favour of a national terminology. The establishment, type-region and a possible standard section for the Rhaetian, and a marker point for its base are discussed. A critical examination is made of the evidence involved in the suggestion that the Norian and Rhaetian are contemporaneous and that the latter cannot be used as a chronostratigraphical unit. World-wide reinterpretation of faunal and field observations does not support this proposition. Alterations to the lower boundary of the Rhaetian are found to be unnecessary and the suggestion that the Germanic facies should be split from the remainder of the stage and placed in the Jurassic is rejected. The Rhaetian is reaffirmed as the final stage of the Triassic, and the base of the Pre
-planorbis
Beds supported as the lower boundary of the Jurassic.
The stratigraphy and palaeontology of the 'Keuper' Series of the central Midlands of England
Authors: WARRINGTON GEOFFREY
Published: October 2009

A reappraisal of the stratigraphical status of the formations constituting the series traditionally termed 'Keuper' in central England is given, based on palaeontological and sedimentological evidence. The 'Keuper' Sandstone is a fluvial facies representing a sub-aerial deltaic environment and is of upper Scythian and Anisian age. At the base of the 'Keuper' Sandstone is a significant disconformity which is probably equivalent to the Hardegsen Disconformity of Germany.

The 'Keuper' Waterstones are a marine or semi-marine facies of transgressive nature and represent the distal facies belt of the delta complex. The Waterstones facies is of lower Ladinian age in the central Midlands but is probably older in more northerly districts (Cheshire, Yorkshire, etc).

The Keuper Marl is of Keuper age, representing at least the upper Ladinian and Carnian stages of the European Keuper, and is largely the deposit of a hypersaline epeiric sea.

A correlation chart and a series of palaeographical maps, based on the new evidence provided in this paper, are presented.
Graptolite succession across the Ordovician–Silurian boundary in south-eastern Alaska
Authors: CHURKIN MICHAEL , CARTER CLAIRE , EBERLEIN GEORGE DONALD
Published: October 2009

The first discovery in North America of a succession of graptolite faunas across the Ordovician–Silurian boundary has been made on Esquibel Island, in south-eastern Alaska, where five graptolite zones are represented in an 18 m interval of shale in the Descon Formation. Despite the thinness of the graptolite zones, no stratigraphical breaks can be inferred from more complete graptolite successions known elsewhere. The Alaskan faunas can be closely correlated with those of the standard British zones—the
Dicellograptus anceps
Zone (uppermost Ordovician), the
Glyptograptus persculptus
Zone (lowermost Silurian) and the immediately overlying
Akidograptus acuminatus, Orthograptus vesiculosus
and
Monograptus cyphus
Zones of the Lower Silurian. They thus give evidence of the cosmopolitan distribution of graptolite faunas during latest Ordovician and earliest Silurian time.
On the Older Palæozoic (Protozoic) Rocks of North Wales
Authors: Sedgwick A.
Published: October 2009

Introduction

In a paper read before the Geological Society in June, 1843, and intituled, “ An Outline of the Geological Structure of North Wales,” the author gave a description of those stratified rocks in the northern counties of the principality which are of anterior date to the mountain limestone. Those rocks he separated into the following three principal groups:—

1.

Chlorite-slate and mica-slate. These form a band along the north-western side of the promontory of Carnarvonshire from Porth Dilleyn to Bardsea island.

2.

Greywacke and roofing slate, often containing calcareous bands, and alternating with Plutonic rocks of cotemporaneous formation: and these rocks the author terms, in his present paper, the
Protozoic
, group. They extend in an east and west direction, from the borders of Shropshire to the western coast of Carnarvonshire; and their north-western boundary, from the confines of Shropshire to Yspytty Evan, coincides nearly with the Holyhead road; and from Yspytty Evan to Conway, with the Conway river.

3.

An overlying and sometimes unconformable deposit of flagstone, &c., coterminous along the Holyhead road and Conway river with the last-mentioned principal group; but bounded towards the north-west by an overlying range of mountain limestone.
Some Account of a Fossil Tree found in the Coal Grit near Darlaston, South Staffordshire
Authors: Dawes John S.
Published: October 2009

Within the last few days (Jan. 1844), an exceedingly well-preserved and extraordinary specimen of a fossil tree has been discovered in a stone quarry near the town of Darlaston. The rock, which also contains Calamites and other drifted coal fossils, is the White Grit, which overlies the thin carboniferous measures, on the north-eastern side of the South Staffordshire coal field; the fossil, 39 feet in length, lies in the ripple-marked stone, at a depth of 16 yards from the surface, the nearest bed of coal being ten yards below it. The root end is towards the deep, and in a westerly direction. Its angle of inclination is about 6°, which also corresponds with the dip of the strata; distinct traces of four branches may be observed upon the stem, three of which, when it was found, were still attached, and apparently in the position in which they grew, but one of them was moved aside from its original direction. They extended in length from 6 to 8 or 9 feet, having a diameter varying from 6 to about 4 inches, and the upper one yet remains attached, and shows a remarkable uniformity in its thickness. The others were in part broken to pieces, and some of them lost before I was aware of the specimen being in the quarry; but I understand that each appeared to terminate abruptly, having a small portion of coaly matter adhering to the end.
On the Trap-rock of Bleadon-hill, in Somersetshire
Authors: Williams D.
Published: October 2009

Since the author's last communication on this subject, the completion of the Railway cutting through the western point of Bleadon Hill has disclosed several new and remarkable facts; and these have so materially changed his views respecting the origin of trap and other rocks, that he has been led to draw up a supplement to his former papers.

The Mountain Limestone of Bleadon Hill and that of Uphill have been disconnected by two great downcast faults since the lias was deposited, that on the Bleadon side ranging E. by N. and W. by S., and that on the Uphill side N. E. and S. W. In the space between them, which is about a quarter of a mile broad, the surface consists of lias and new red sandstone.

In the cutting the Bleadon fault is finely exposed, and its southern side presents a great slickenside wall of limestone and trap, which dips to the south at an angle of 70°. On the northern side of the fault, the lias is seen, curiously faulted, to some little distance; it then dips considerably towards the fault, the inclination increasing, and the beds at last going down with the fault, the lias inclining towards it at an angle of 45°. The lias, where abutting against the trap, has no appearance of having been altered, by it.
On the Occurrence of Phosphorite in Estremadura
Authors: Daubeny Charles , Widdrington
Published: October 2009

A Statement having frequently been made by mineralogical writers, that there exists in the Spanish province of Estremadura an extensive formation of Phosphate of Lime, it was considered by some leading Members of the Royal Agricultural Society of England an object of importance to learn the truth of these statements; and the authors were, therefore, commissioned to ascertain where and under what circumstances the substance in question was found; what facilities existed in the country for procuring it and conveying it to the coast; and whether, if used as a manure, it was of a nature to serve as a substitute for the bone earth, now employed extensively in husbandry.

The original authority for the statement, that there occurs in Estremadura a certain mineral which, when thrown upon live coals, becomes phosphorescent, was found to be William Bowles, who, in his introduction to the Natural History and Physical Geography of Spain (2d edit. 4to. Madrid, 1782, p. 6.), relates, that, at the foot of a range of mountains running E. and W., and called the Mountains of Guadaloupe, and in the immediate vicinity of a place called Logrosan, the royal road is traversed obliquely, from N. to S. by a
vein
of Phosphoric stone. This stone was said to be of a pale colour, and without taste; and, when sprinkled upon live coals, to emit a blue flame, but no smell.