bluuebunny/crossref_metadata_2025 huggingface dataset:
IV.—Note on Remains of the Emu from the Wellington Caves, New South Wales
Authors: Davies William
Published: May 2009

A few bones of birds are recorded by Mr. Gerard Krefft as having been found in association with the remains of the extinct mammalia, which abound in the breccias of the caves and fissures in the limestone rocks of the Wellington Valley, New South Wales. The bird bones belong to various genera and species, but only those of the Emu seem, as yet, to have been identified, and these were in the possession of the late Rev. W. Branthwaite Clarke. They do not appear to have been described, nor is the number of fragments in the collection stated. Unfortunately Mr. Clarke's valuable collection was deposited for exhibition in the “Palace Garden,” a temporary building erected for the Intercolonial Exhibition at Sydney in 1879–80, and was consumed in the disastrous fire which destroyed the building and its contents soon after its close; and, as regards Mr. Clarke's specimens, the destruction of the material evidence on which the early appearance of the Emu in Australia was founded. However, there is preserved in the palæontological collections in the British Museum, South Kensington, a portion of a shin bone, that I discovered some years ago in a collection of fragmentary remains from the Wellington caves, presented to the National Collection by the Trustees of the Australian Museum, Sydney. The specimen is the distal end of a right tibia, somewhat mutilated, but is interesting as being additional evidence, still existing, of the Emu having been contemporary with the great extinct Marsupials; as such, and on account of the rarity of its remains, I have thought it worthy of a short notice. Compared with the tibia of an adult Emu (Dromaius Novœ-Hollandiœ), it is indistinguishable from it, but has belonged to a larger individual, as shown by the annexed few measurements, in inches and tenths.
II.—Contributions to the Palæontology of the Yorkshire Oolites
Authors: Hudleston Wilfrid H.
Published: May 2009

Several trochiform shells found in the Jurassic rocks, which were formerly referred either to Trochus or to Solarium, have in more recent years been regarded as related to the genus Onustus. I am not aware who was the first author to adopt this view, but we find Hébert and Deslongchamps (1860) recognizing the genus in the Callovian of Montrueil Bellay. Subsequently Lycett (Suppl. to the Great Ool. Moll. p. 103) gave a diagnosis, more especially as applicable to the Jurassic species, and described Onustus Burtonensis from the Forest Marble of Burton Bradstock.
V.—Metalliferous Deposits
Authors: Ochsenius Carl
Published: May 2009

The origin of metalliferous deposits has long been a subject of discussion. Professor Joseph Le Conte, however, seems to have arrived at a very decided opinion on this question, for in a contribution to the “American Journal of Science” (3rd series, xxvi. p. 1—19, July, 1883), after referring to Sulphur Banks and Steamboat Springs in California, he says: “Thus then subterranean waters of any kind, but especially alkaline, at any temperature, but mostly hot, circulating in any direction, but mainly upcoming, and in any kind of waterway, but mainly in open fissures, by deposit, form metalliferous veins.”
I.—Contributions to the Palæontology of the Yorkshire Oolites
Authors: Hudleston Wilfrid H.
Published: May 2009

Bibliography, etc.—The type specimen of Turbo lævigatus, Phil., has not been seen by me; but since there are some grounds for regarding the fossil, usually so described, as a Neritopsis, the identification becomes important. We must therefore fall back upon Phillips's figure, and upon such collateral evidence as, in the absence of description, may be available. Phillips in the early editions of the G.Y. considered Bean's specimen from the Dogger as identical with Nerita lævigata, Sow. (M. C. t. 217, fig. 1), which he regarded as a Turbo rather than a Nerita. This identification of Phillips has not been endorsed by subsequent writers. D'Orbigny believed that he recognized in Turbo lævigatus, Phil., Delphinula gibbosa, Thorent (Mém. S. G. Fr. 3, p. 260, pl. 22, fig. 10). D'Orbigny's figure, making due allowance for enlargement, is very similar to the one by Phillips.
I.—On the Close of the Highland Controversy
Authors: Lapworth Charles
Published: May 2009

All those British geologists who have interested themselves in the long-vexed question of the geological position and true mode of origin of the Metamorphic rocks of the Highlands of Scotland must have read with the greatest interest and pleasure the clear and vivid “Report on the Geology of the North-West of Sutherland,” by Messrs. Peach and Horne, in the pages of “Nature” for November last; and the manly and candid Introductory Observations by the Director-General of the Geological Survey. Not only does the publication of this Report put an end to one of the most keenly agitated controversies in the history of British Geology, but it explains and harmonizes the diverse views of the contending parties. The issue appears to me to be most creditable to all concerned. For many years the Highland controversy has appeared to outsiders, and to those geologists who were unaware of the difficulties attending the stratigraphy of the older rocks, as a trivial dispute between the Geological Survey on the one hand and a few misguided amateurs on the other.
VI.—Contour-Lines on Geological Maps
Authors: Lyman Benjamin Smith
Published: May 2009

AS one of your reviewers now some years ago criticized unfavourably the method of representing geological structure in maps by contour lines upon a bed of coal or other rock, and as, like him, most geologists are not yet practically familiar with the method, useful though it be, and nobody that might be thought wholly unbiassed has replied in your pages to his attacks, it may not be improper to call your attention to the unprejudiced opinion and explanation of Mr. Charles A. Ashburner, the geologist in charge of the survey of the anthracite region, under the Geological Survey of Pennsylvania, who has up to this time published 26 large sheets of most elaborate maps and sections with one volume of text. After careful examination before adopting the method and after using it several years he writes of it in the report (page 8) as follows:—
The palaeogeographic position of the Lake District in the early Ordovician
Authors: Fortey R. A. , Owens R. M. , Rushton A. W. A.
Published: May 2009

The early Ordovician was a time of maximum continental separation and hence a time when faunal evidence can be used to assess palaeogeography in a critical way. We summarize the known trilobite occurrences (18 genera) from the Arenig–Llanvirn of the Lake District, and record some genera for the first time. Maps of the distribution of some of these forms are given. All genera exceptCyclopygewere confined to the Gondwana continent at the time, and some are known from many localities; and two species are widespread in England, Wales, France, Iberia and Bohemia. The fauna is entirely distinct from those of Scandinavia and North America. All the palaeontological evidence points to the Lake District being adjacent to Ordovician Gondwana. In the earlier Ordovician it is not reasonable to suggest that the Iapetus Ocean lay to the south of the Lake District as did Allen (1987).
The Cenozoic evolution of the Lundy Pull-Apart Basin into the Lundy Rhomb Horst
Authors: Arthur M. J.
Published: May 2009

The NW–SE Cornubian fault zones (FZs) continue to southwest Wales, where they caused dextral offsets during the late Stephanian. A fault bounded area of Devonian–Carboniferous strata, intruded by the Tertiary Lundy Igneous Complex, forms the Lundy Rhomboid. It originated as the Lundy Rhomb Graben, created by 28–40 km of Tertiary sinistral strike–slip faulting along the left-stepping NW–SE Sticklepath–Lustleigh FZ (SLFZ). Tertiary sedimentation in the graben was accompanied by intrusion of the 2.5–4.0 km thick igneous complex into its basement. Sedimentation later spread beyond the graben to form a ‘steer's horns’ basin, of which the Stanley Bank and West Lundy basins are remnants. The strata of the rhomb graben and the ‘steer's horns’ basin constituted the perhaps 4 km deep Lundy Pull-Apart Basin. Subsequent relatively minor dextral faulting on the left-stepping SLFZ inverted the graben into the Lundy Rhomb Horst; the basement of the graben was uplifted ≮ 1–2 km (net) and exposed by erosion of the Tertiary strata. The pull-apart basin developed at the intersection of reactivated Hercynian NW–SE transform FZs, and E–W subduction zone thrusts. Cenozoic N–S tensional and compressional reactivations of the thrusts were respectively associated with transtensional development of the pull-apart basin, transpressional of the rhomb horst.
Sedimentation of a Lower Cretaceous (Aptian) coral mound complex, Zaraya Mountains, northern Spain
Authors: Fernandez-Mendiola P. A. , Garcia-Mondejar J.
Published: May 2009

A Lower Cretaceous mixed carbonate-siliciclastic sequence is well exposed in the Zaraya Mountains in Guipuzcoa Province, northern Spain. The sequence begins with interfingering deltaic platform facies and marine patch-reef carbonates. This unit is dominated by mudstones and sandstone with minor interbeds of shallow-water carbonates (calcareous mudstones and sandstones and grainstone-packstones). A thick mixed carbonate-terrigenous unit overlies the siliciclastics and is composed principally of limestones and marls. Periodic influx of terrigenous sediments over a dominantly carbonate sea-floor gave rise to repeated cycles typical of a mixed shallow-water platform. Demise of the southerly derived deltaic input allowed the development of a mainly carbonate third unit. Large (several metres across) bioherms resulted from high in situ organic productivity (mechanical breakage of bioclasts, algal-induced precipitation, trapping and baffling of lime mudstone). The mounds grew making up a coral carbonate mound complex. This prograded to the south, towards a small backreef basin, and slightly retreated in its forereef margin. A period of tectonic instability is thought to have been responsible for the drowning of the shallow-water complex, which was unable to keep pace with relative sea-level rise.
Accuracy of historical earthquake locations in Britain
Authors: Musson R. M. W.
Published: May 2009

If historical earthquake data are to be used in studies of regional seismotectonics, it is essential to include information on likely locational uncertainty. Contributory factors include both geophysical parameters and the social environment of the event. A reconstruction of how a recent earthquake might have appeared had it occurred 300 years ago is used to demonstrate the effects of documentary survival. Limits of uncertainty are estimated for two historical earthquakes (7 October 1690 and 28 November 1880) and shown to be large. It is recommended that such events should be shown on epicentral maps as areas rather than points.
The Mathry Dyke, a quartz-dolerite intrusion of probable Carboniferous age in southwest Wales
Authors: Cave R. , Cornwell J. D. , Evans A. D.
Published: May 2009

A previously unrecorded quartz-dolerite dyke some 40 km long and up to 15 m wide intrudes Lower Palaeozoic rocks in southwest Wales between Mathry and Llanboidy. It is of discontinuous subcrop but has an overall WNW trend. This crosscuts the Caledonian strike of the country rocks but is parallel with the line of the Hercynian front to the south. The dyke is probably related to the suite of Dinantian basalts and dolerites near the Bristol Channel, to the east of the South Wales Coalfield.
Sm—Nd isotopic age of Precambrian—Cambrian boundary in China
Authors: Jie-Dong Yang , Wei-Guo Sun , Zong-Zhe Wang , Yin-Xi Wang
Published: May 2009

By the new method of Sm—Nd isotopic dating on phosphatic small skeletal fossils and collo-phanite minerals, the Zhongyicun Member of the earliest Cambrian Meishucun Stage at Meishucun in Yunnan, southern China, has been dated at 562.8 ± 7.9 Ma and 562.1 ± 5.7 Ma. Another Sm—Nd age, 570.3 ± 17.1 Ma, has been obtained with samples from the Zhongyicun Member in Yunnan and its stratigraphic equivalents in Sichuan and Xinjiang. These data tend to suggest that the best age estimate of the Precambrian—Cambrian boundary is very likely within the range of 560–570 Ma. As biophosphates and sedimentary phosphates are widely distributed in sequences of the Precambrian—Cambrian transition, the Sm-Nd isotopic method is recommended as an effective approach for precise dating of the initial Cambrian boundary.
Biotite porphyroblast nucleation and growth: control by microfracture of pre-existing foliations in schists in the Robertson River Metamorphics, Australia
Authors: Davis B. K.
Published: May 2009

A macroscopic fold formed during the fourth deformation, D4, in the Robertson River Metamorphics, north Queensland, Australia. Growth of biotite, garnet, staurolite and andalusite porphyroblasts also occurred synchronous with D4. Only biotite porphyroblasts have formed preferred alignments across the fold, and they define two dominant orientations. The more common is parallel to D4 fold axes, which is also parallel to D1 D2 and D4 intersection lineations. The other varies up to 90° from this within the D4 axial plane. Mineral elongation lineations do not reflect the extension direction of the deformation in which they formed (D4), but are a function of pre-existing anisotropics in the rock parallel to intersection lin-eations. Porphyroblast growth is inferred to be a result of microfracturing along favourably oriented linear anisotropics formed by multiple intersection of foliations, as well as parting of the the S1, and S2 foliations.
Trace fossils and biofabrics at the Precambrian–Cambrian boundary interval in western Mongolia
Authors: Goldring R. , Jensen S.
Published: May 2009

A small suite of trace fossils from the Zavkhan Basin (Govi-Altay) includes many of the ichnotaxa typical of the Nemakit-Daldynian, Tommotian and younger Cambrian stages, and other indeterminate forms. The traces are almost entirely from the sandstone intervals of the large-scale alternations of carbonate and siliciclastic sediments, thus emphasizing the facies and taphonomic controls on trace fossil distribution, and hence the inherent difficulties in using trace fossils in detailed global correlation, especially in using first appearances. The assemblage of traces and biofabrics is seen as resulting from the partly non-uniformitarian (non-actualistic) sedimentary environments that pertained over the boundary interval, rather than as evolutionary failures and subsequently vacated environments.
Integrated chemo- and biostratigraphic calibration of early animal evolution: Neoproterozoic–early Cambrian of southwest Mongolia
Authors: Brasier M. D. , Shields G. , Kuleshov V. N. , Zhegallo E. A.
Published: May 2009

Five overlapping sections from the thick Neoproterozoic to early Cambrian sediments of western Mongolia were analysed to yield a remarkable carbon-isotope, strontium-isotope and small shellyfossil (SSF) record. Chemostratigraphy suggests that barren limestones of sequences 3 and 4, which lie above the two Maikhan Uul diamictites, are post-Sturtian but pre-Varangerian in age. Limestones and dolomites of sequence 5, withBoxonia grumulosa, have geochemical signatures consistent with a post-Varangerian (Ediacarian) age. A major negative δ13C anomaly (feature ‘W’) in sequence 6 lies a shortdistance above anAnabarites trisulcatusZone SSF asemblage with hexactinellid sponges, of probable late Ediacarian age. Anomaly ‘W’ provides an anchor point for cross-correlation charts of carbon isotopes and small shelly fossils. Trace fossil assemblages with a distinctly Cambrian character first appear in sequence 8(PurellaZone), at the level of carbon isotopic feature ‘B’, provisionally correlated with the upper part of cycle Z in Siberia. A paradox is found from sequence 10 to 12 in Mongolia: Tommotian-type SSFs continue to appear, accompanied by Nemakit-Daldynian/Tommotian-type87Sr/86Sr ratios but by increasingly heavyδ13C values that cannot be matched in the Tommotian of eastern Siberia. The steady rate of generic diversification in Mongolia also contrasts markedly with the Tommotian ‘diversity explosion’ in eastern Siberia, which occurs just above a major karstic emergence surface. One explanation is that sequences 10 to 12 in Mongolia preserve a pre-Tommotian portion of the fossil record that was missing or removed in easternSiberia. The Mongolian sections certainly deserve an important place in tracing the true course and timing of the ‘Cambrian radiation’.
Pb-isotope evidence on the origin of the West Shropsh orefield, England
Authors: Haggerty R. , Rohl B. M. , Budd P. D. , Gale N. H.
Published: May 2009

Pb-isotope data on ore galenas from the West Shropshire orefield show a significant spread of20pb/204pb values, with minor variation in 207Pb/204Pb and 208Pb/204Pb ratios. These indicate that lead was derived from multiple sources, some of them uranium-enriched and incompletely mixed prior to ore deposition. Four possible mineralizing agents are considered: circulating sea-water, metamorphic waters, basinal brines and convecting formation waters. Pb-isotope data exclude a circulating sea-water origin for the mineralization, and best support a convecting formation water mineralizing agent. A model involving a single fluid tapping multiple lead sources is proposed to explain the observed Pb-isotope variation.
An interpretation of the gravity anomaly at Warlingham, Surrey
Authors: Kearey P. , Rabae A. M.
Published: May 2009

An interpretation of the negative gravity anomaly at Warlingham, Surrey, controlled by a seismic reflection profile and several boreholes, suggest that it may be caused by a wedge-shaped body of lowdensity Upper Palaeozoic rocks. The seismic reflection data suggest that the upper boundary of the body may be thrust-controlled and originated during Variscan compression. The location of the thrusting appears to be controlled by the southern margin of the stable London Platform. Comparison with similar structures of this type elsewhere suggests that the Variscan Front in this area lies just to the north of Warlingham.
Sedimentary rhythms in the Jurassic and Cretaceous of Svalbard
Authors: Dypvik Henning
Published: May 2009

The Janusfjellet Subgroup on Svalbard consists on a 400 to 500 m thick sequence representing shallow marine depositional environments. Coarsening-upward units, often separated by carbonate beds, are commonly found in rhythmic developments. Rhythmicities (285000(?) and 850000(?) years) in the sedimentary sections show periods which may reflect pulses in nearby sea-floor spreading or strike-slip fault regimes. An astronomical control of the cycles cannot be excluded, although such changes most probably should be expected in superimposed episodes of shorter duration.
The geology and geomorphology of the Beacon Cottage Farm Outlier, St Agnes, Cornwall
Authors: Jowsey N. L. , Parkin D. L. , Slipper I. J. , Smith A. P. C. , Walsh P. T.
Published: May 2009

The mid-Oligocene sediments forming the Beacon Cottage Farm Outlier at St Agnes, Cornwall, have a stratigraphical and geomorphological importance which is out of all proportion to their modest residual bulk (some 300000 m3). During 1986–8 61 holes were sunk into the area surrounding Beacon Cottage Farm; many penetrated the Palaeozoic floor beneath the outlier. Collectively, these show that the outlier mostly covers rotten granite and Killas. The sub-Oligocene unconformity is uneven and varies in altitude by at least 20 m. The local Bovey Formation succession comprises two members: Basal Sand, which is often pebbly, and sandy silts, known commercially as Candle Clay, the whole totalling a maximum of 8.9 m. There is indirect evidence either that slopes on the rotted Palaeozoic floor locally exceed 45° or that several post-mid-Oligocene faults affect the outlier. We conclude that the Beacon Cottage Farm sediments probably represent aeolian, colluvially and fluvially redistributed rotten rock residues, formed locally during a break in the long period of late-Palaeogene subtropical weathering and pediplanation. The outlier is considered in relation to the geomorphological evolution of the Cornubian Massif.
Is Gaia endothermic?
Authors: Hsü K. J.
Published: May 2009

Geological evidence suggests that Gaia is endothermic: her body temperature has varied, but within limits; there has been no runaway greenhouse like Venus, nor deep freeze like Mars. This paper presents a hypothesis that the Earth's climate has been ameliorated by living organisms: they have served either as heaters or air-conditioners, and their ecological tolerance is the sensor of Gaia's thermostat. At the beginning, 3.8 or 3.5 Ga ago, only anaerobic autotrophs capable of tolerating high temperatures thinned out the atmospheric CO2 through carbon fixation. Fossil organic carbon was utilized by anaerobic heterotrophs to reinforce the effectiveness of the late Archean greenhouse, when solar luminosity was weaker than it is now. With the increasing solar luminosity during early Proterozoic time, new life forms such as cyanobacteria evolved, removing CO2 from the atmosphere and storing it in stromatolitic carbonates. Over-eager cyanobacteria may have consumed too much greenhouse CO2 to cause glaciation. Their decline coincided in timing with the rise of the Ediacaran faunas which had no carbonate skeletons. The change in the mode of carbon-cycling may have started the warming trend after the Proterozoic glaciation. The Cambrian explosion was an event when skeletal eukaryotes usurped the function of prokaryotes in removing greenhouse CO2 through CaCO3 precipitation. With the evolution of land plants, coal-makers took over the ‘air-conditioning’ duty. They over-did it, and Permo-Carboniferous glaciation ensued. After a wholesale turnover of the faunas and floras at the end of the Palaeozoic, more CO2 was released than fixed in early Mesozoic time. The warming trend reached its zenith in the early Cretaceous, when flowering trees and calcareous plankton began to flourish. The decline since then, with a temporary restoration during early Palaeogene time, could be a manifestation of the varying efficiency of extracting and burying carbon dioxide, in the form of inorganic and organic carbon. The relation of atmospheric CO2 and climatic variation is documented by study of air bubbles in ice cores. Yet there is also correlation to astronomical cycles. The latter seem to have triggered changes which are amplified by feedback mechanisms of carbon cycling.
Neotectonic development of the Struma (Kraištid) Lineament, southwest Bulgaria and northern Greece
Authors: Zagorčev I. S.
Published: May 2009

The Struma (Kraištid) Lineament is a part of a fault belt of regional importance. It strikes NNW-SSE and cuts through different Alpine tectonic zones along the whole Balkan Peninsula. Normal and strike-slip faults occurred in environments of extension and graben formation during collapse after or between collision epochs in the Palaeogene and Early Neogene, and in a back-arc extensional environment during the neotectonic (end of Middle Miocene-Quaternary) stage. The last Alpine compression phase occurred in the beginning of the Miocene, and Early-Middle Miocene planation formed the initial peneplain. New intense faulting marked the beginning of the neotectonic stage (Late Badenian), and the neotectonic development, including sedimentation, proceeded in four regional macrocycles: Badenian-Sarmatian; Maeotian; Pontian-Dacian; and Eopleistocene-Pleistocene. The neotectonic development was marked by formation of the Serbo-Macedonian Swell as well as by rifting (the Vardar and Struma rifts).
The age of the Büyük Menderes graben (west Turkey) and its tectonic implications
Authors: Seyіtoǧlu Gürol , Scott Barry C.
Published: May 2009

The age of formation of the Büyük Menderes graben (middle Burdigalian-middle Serravallian) is earlier than previously considered (Tortonian). This supports the contention of Seyitogˇlu & Scott that north-south extensional tectonics in west Turkey commenced at the latest during early Miocene time, following a Palaeogene compression.
Chronometric calibration of mid-Ordovician to Tournaisian conodont zones: a compilation from recent graphic-correlation and isotope studies
Authors: Fordham Barry G.
Published: May 2009

Three available graphic-correlation analyses are used to calibrate mid-Palaeozoic conodont zonations: Sweet's scheme for the mid- to Upper Ordovician; Kleffner's for the mid- to Upper Silurian; and Murphy & Berry's for the lower and middle Lower Devonian. The scheme of Sweet is scaled by applying the high-precision U-Pb zircon date of Tucker and others for the Rocklandian and linked with that of Kleffner by scaling the graptolite sequence of the Ordovician-Silurian global stratotype section to fit two similarly derived dates from this sequence. The top of Kleffner's scheme, all of Murphy & Berry's, as well as standard zones to the Frasnian are calibrated by using tie-points of the latest Cambridge-BP time-scale (GTS 89). However, the recent microbeam zircon date by Claoué-Long and others for the Hasselbachtal Devonian-Carboniferous auxiliary stratotype is used to calibrate the standard Famennian zones. Also the similarly derived but preliminary determination reported by Roberts and others from the Isismurra Formation of New South Wales is tentatively taken as the top of the Tournaisian and so used to calibrate Tournaisian zones. Despite the considerable extrapolation required to compile these schemes and their inherent errors, the resultant time-scale closely agrees with other dates of Tucker and others from the Llanvirn as well as the GTS 89 Homerian-Gorstian tie-point. This suggests that stratigraphic methods can be usefully applied to geochronometry. The Llandovery appears to have lasted longer (16 m. y.) than usually envisaged and the Ordovician-Silurian boundary may need to be lowered to approximately 443.5 Ma. Certainly, chrons varied widely in duration and further stratigraphic studies to estimate their relative durations as well as high-resolution dating for their calibration will be crucial to more accurate biochronometries.
The lichid trilobiteRadiolichasin the Silurian of Arctic Canada and Gotland, Sweden
Authors: Adrain Jonathan M. , Ramsköld Lars
Published: May 2009

Radiolichashas been a poorly known and exclusively Devonian genus of very limited diversity.Radiolichas raydaviesisp. nov. andR. davedaviesisp. nov. are the best-known members of the genus, and extend its stratigraphic and geographic range to the Wenlock of the central Canadian Arctic. A further Silurian occurrence is an unnamed species from the Wenlock Slite Beds of Gotland, Sweden.Radiolichasis most similar toDicranogmus. Together, the genera lack any of the robust trochurine apomorphies (linear pygidial postaxial ridge, prominent pygidial border, prominent cranidial fossula) and appear to fall outside the phylogenetic structure of that subfamily. They are similar to members of the Tetralichinae, particularly in pygidial features, but lack the composite cranidial lobe characteristic of that subfamily. Their systematic position is presently unresolved.
Pluton emplacement by wall-rock thrusting, hanging-wall translation and extensional collapse: latest Devonian plutons of the Cobequid fault zone, Nova Scotia, Canada
Authors: Koukouvelas I. , Pe-Piper G. , Piper D. J. W.
Published: May 2009

Latest Devonian A-type granite-gabbro plutons, in part ductilely deformed, are spatially associated with the strike-slip Cobequid fault zone. The youngest intrusions are close to the Cobequid fault zone, which was the main conduit for magma. Two phases of deformation accompanying magma emplacement are recognized. Early magmas intruded ductile rocks during left-lateral oblique thrust movements. A second stage of right-lateral oblique slip normal faulting accommodated uplift of the plutons when coarse granite was emplaced in the crestal regions. Cross-cutting late stage porphyries, granitic clasts in marginal basins cut by granitic dykes, and superposition of brittle on ductile structures all indicate rapid uplift of the plutons. The geometry of the Cobequid fault zone shows that pluton emplacement was not the result of extension in releasing bends during transcurrent shear. Rather, flower-structure high-angle faults acted as magma conduits and space was created by two processes: translation of wall rocks along thrust faults at depth, developing space away from the master fault zone and backward collapse of the uplifted magma chamber creating space towards the fault zone.
On the first partial skull of an ankylosaurian dinosaur from the Lower Cretaceous of the Isle of Wight, southern England
Authors: Norman David B. , Faiers Tamsin
Published: May 2009

The specimen is identified as the partial cranium of a nodosaurid ankylosaur (Ornithischia: Thyreophora) on the basis of the presence of bone which is fused to the dorsal surface of the skull and has secondarily closed the upper temporal fenestrae. The only unequivocally nodosaurid material recovered from the Isle of Wight to date comes from Wealden facies, and has been referred to the genusPolacanthus; it is considered highly probable that this new skull is referable to the same genus. Despite having undergone abrasion, through post-emergence water-rolling, the skull and cranial walls have proved to be relatively informative of the general anatomy of the braincase and the neural and vascular anatomy of this part of the head. The anatomy of the braincase of most ankylosaurs (with the notable exception of the juvenile specimens of the ankylosauridPinacosaurus) is surprisingly poorly known, despite the relative abundance of cranial material in North American and Asian collections.

The cranial neural and vascular anatomy is well shown in this specimen and enables the first detailed description of nodosaurid endocranial structures. The general form of the brain can be outlined from the structure of the endocast and the principal lobes can be identified; the majority of the cranial nerves have been identified, and a significant component of the associated vascular system is also visible. In most respects the endocast shows a neural anatomy which is common to that known in most dinosaurs. When compared to their nearest relatives, the ankylosaurid ankylosaurs (Euoplocephalus), the nodosaurid endocranial cast shows a more pronounced cerebral flexure, a forebrain which is broader and more expanded dorsally, and a more prominent cerebellum (although there is no evidence for a floccular lobe); there are minor differences in the arrangement of the cranial nerves, and the dorsal portions of the vascular system are better shown.

Because of erosion, the olfactory lobes of this specimen of cf.Polacanthusare not preserved, and cannot be compared to those of ankylosaurid ankylosaurs; the latter are unusual in the strong separation of the lobes (reflected in the divergent olfactory stalks); this feature may be associated with the very complex passages within the nasal region of the skull, which are lacking in the nodosaurids described to date.
Plio-Quaternary volcanism in Ecuador
Authors: Barberi F. , Coltelli M. , Ferrara G. , Innocenti F. , Navarro J. M. , Santacroce R.
Published: May 2009

Extensive sampling, major element chemistry on over 300 samples and K-Ar radiometric dating have been carried out on the Ecuadorian Upper Tertiary–Quaternary volcanoes. The results show important space–time variations of the volcanic activity, between Late Miocene time and the present. In Late Miocene time a continuous volcanic belt, located approximately along the present volcanic front (VF), affected the whole country from the Cuenca basin to the south, up to Colombia to the north. Major changes occurred at about 5 Ma: volcanic activity stopped south of the Guayaquil fault belt and never resumed; to the north the active volcanic axis shifted eastward to the Cordillera Real (CR) area with a simultaneous relative decrease in intensity. Since Early Quaternary time the volcanic belt widened westward to the Western Cordillera where the volcanism resumed at about 1.5–1.0 Ma, giving rise to the very wide active volcanic zone of Ecuador.

The Plio-Quaternary products show significant longitudinal and latitudinal chemical and mineralogical changes. Volcanics of the VF and Interandean Depression contain amphibole and define a calc-alkaline trend with a K2O content lower than that of the CR products, which are characterized by a mostly anhydrous phenocryst assemblage. In both areas andesites dominate, but extreme compositions (basaltic andesites and rhyolites) are more diffuse in the CR than the VF. No significant transverse zoning has been detected in the northern region (north of the Chota-Mira transverse tectonic line). The observed temporal and spatial variations are interpreted as a result of the subduction of the Carnegie Ridge anomalous oceanic crust, underthrusting of which began approximately 6 Ma ago.
Deformation of Anhydrite–gypsum rocks in central Spitsbergen
Authors: Harland W. B. , Mann A. , Townsend C.
Published: May 2009

Early Permian anhydrite–gypsum strata in central Spitsbergen show deformation of sulphate nodules in dolostone (chicken-wire structure) to varying degrees from imbricate to extreme flattening and elongation. These shear zones often occur between undeformed layers of apparently similar strata.

The shear zones indicate a minimum displacement of between 0.5 and 1.5 km to the ENE of Zechstein and later strata over the Nordfjorden Block. Resultant folding and faulting over the Billefjorden Fault Zone represent an eastward manifestation of the Eocene West Spitsbergen Orogeny.
Volcanism on Gough Island: a revised stratigraphy
Authors: Maund J. G. , Rex D. C. , Le Roex A. P. , Reid D. L.
Published: May 2009

Recent field work on Gough Island combined with K–Ar dating of the lavas requires revision of the age and volcanic stratigraphy. Four main periods of volcanic activity on the island are recognized. These comprise the eruption of the Older Basalt Group which ranges in age from 2.5 to 0.52 Ma, the intrusion of aegerine-augite trachyte plugs (0.8−0.47 Ma), voluminous trachyte extrusion (0.30–0.12 Ma) and finally to eruption of the Edinburgh Basalt (0.20–0.13 Ma).

Within the Older Basalt Group three phases of activity can be recognized; the earliest involving the eruption of pillow basalts and hyaloclastites when the island emerged from below sea level. This was followed by subaerial as-type lava flows and also dyke intrusion (phase two) which probably contributed to forming a large shield-type volcanic island, which in turn supported the eruption and deposition of flat-lying flows on an angular unconformity (phase three). Intrusion of aegirine-augite trachyte plugs occurred concurrently with the latter stages of Older Basalt eruption. After a period of considerable erosion the voluminous trachyte lavas and pyroclastics were erupted. The Edinburgh Basalt, erupted in the vicinity of Edinburgh Peak, represents the youngest volcanic activity on the island.
The nodular granite of Castanheira, north central Portugal: origin of the nodules and evidence for diapiric mobilization of granite
Authors: Reavy R. J. , Hutton D. H. W. , Finch A. A.
Published: May 2009

The Castanheira pluton in north-central Portugal is a small (1000 m × 600 m) granite body of Hercynian age which contains a remarkable abundance of granite-cored, biotite-rimmed nodules. The nodules are interpreted as representing original bubbles in the uppermost volatile-rich zone of a granitic pluton. Strong depletion in K and Rb in the host granite around the nodules suggests that the biotite is magmatic in origin. The nodules may have formed by reaction between chloroferrate(II) complexes in the vapour phase and silicate melt, possibly followed by condensation of the vapour phase to a small granitic core. Motion of the vapour bubble stabilized a gradient in chemical potential with respect to the host granite, giving rise to the nodules. Chemical, petrological and structural data suggest that the pluton was part of a larger granite body, which was forcefully emplaced during synchronous transcurrent shearing. The inferred presence of volatiles, in addition to the pervasive tourmalinization of the roof zone, suggest that the magma was halogen-rich; this may imply that the magma had low viscosity.
Accretion tectonics in northern Eritrea revealed by remotely sensed imagery
Authors: Drury S. A. , Berhe S. M.
Published: May 2009

New details from remotely sensed images of the structure and disposition of broad lithological variations in the Pan-African of northern Eritrea are discussed in the context of accretionary tectonics. The recognition of major north-south structural discontinuities allows the area to be divided into three discrete terranes with apparently different histories of deformation and metamorphism, magmagenesis and sedimentation. The central Hagar Terrane is dominated by large ultramafic masses with a volcano-sedimentary layered sequence, and shows the effects of major sinistral transpression and lateral expulsion. It is bounded to the west by a major fault, the Barka suture, and abuts the older Barka Terrane that comprises metasediments with evidence for polyphase ductile deformation and pre-kinematic dyke emplacement. The Hagar Terrane is thrust against the eastern Nacfa Terrane, which is dominated by low-grade calc-alkaline metavolcanics and immature volcanoclastic sediments intruded by syn-kinematic plutons. These units are pre-dated by an earlier high-grade basement and post-dated by high-level unmetamorphosed silicic volcanics and redbed sediments. The complex is suggested to have been assembled by oblique accretion from the southeast after arc volcanism in the Nacfa Terrane and back-arc extension in the Hagar Terrane ended with the cease of subduction.
An Acadian mountain front in the English Lake District: the Westmorland Monocline
Authors: Kneller B. C. , Bell A. M.
Published: May 2009

The structure of the southern and central English Lake District is that of a southeast-facing monocline, named here the Westmorland Monocline. This 10 km wide zone of highly cleaved, southeast-dipping rocks separates gently dipping, poorly cleaved Borrowdale Volcanic Group to the north from extensively folded but regionally subhorizontal Windermere Group (foreland basin) rocks to the south. The monocline formed early in the local Acadian deformation sequence, and accommodates at least 8 km of uplift. It coincides with the steep concealed margin of the Lake District batholith. A major northwest-dipping shear zone is revealed in the deepest levels now exposed within the monocline, in the Skiddaw Group rocks of the Black Combe inlier.

The monocline has the characteristics of a mountain front, providing significant tectonic elevation across a foreland-dipping panel of rocks, with no hinterland-dipping thrust visible at the surface. We interpret the uplift as the consequence of a southeast-vergent thrust with a gently northwest-dipping ramp beneath the central Lake District, continuing southeastwards as a flat detachment beneath the Windermere Group. A displacement up the ramp of about 20 km is accommodated by backthrusting within the monocline and by shortening within the Windermere Group of the hangingwall southeast of the monocline. The tip lies beyond the limit of the Lower Palaeozoic inlier, beneath Carboniferous cover.
A modern analogue for the Lower Ordovician Obolus conglomerate of Estonia
Authors: Hiller Norton
Published: May 2009

Phosphate-bearing rocks of the lower Ordovician Kallavere Formation, northern Estonia, contain diverse fragments and, more rarely, complete shells of the phosphatic inarticulate brachiopods Schmidtites and Ungula. In places the concentration of brachiopod debris in sandstones is so dense that economically exploitable seams of phosphorite are formed. A directly analogous situation occurs along the coast of Namibia today. In places the extant phosphatic inarticulate brachiopod Discinisca is washed up on the beach in such large numbers that its shells dominate the littoral sediment. The distribution range of this species suggests that it is a product of the Benguela upwelling ecosystem, and the inference is drawn that the Estonian deposits are the products of a similar palaeo-upwelling system.
Basement fractures in North Wales: their recognition and control on Caledonian deformation
Authors: Wilkinson I. , Smith M.
Published: May 2009

A detailed survey of the patterns of regional deformation in North Wales has revealed the presence of several discrete, linear zones of anomalous deformation. These zones are distinguished by atypical finite strain values, intense tight to isoclinal folding, non-axial planar cleavages and high metamorphic gradients. A history of prolonged tectonic activity along these zones is indicated by their influence on sedimentation and volcanism. It is proposed that these zones reflect the deformation of the Lower Palaeozoic cover above pre-existing basement fractures. These basement fractures form a framework which divides North Wales into a series of blocks and sub-blocks. The end-Caledonian deformation is explained by a transpression model dominated by SE-directed shear with minor components of strike-slip localized in these zones. The application of this model to other parts of the Welsh Basin is briefly considered.
Carbon- and oxygen-isotope stratigraphy of the English Chalk and Italian Scaglia and its palaeoclimatic significance
Authors: Jenkyns H. C. , Gale A. S. , Corfield R. M.
Published: May 2009

A detailed carbon- and oxygen-isotope stratigraphy has been generated from Upper Cretaceous coastal Chalk sections in southern England (East Kent; Culver Cliff, Isle of Wight; Eastbourne and Seaford Head, Sussex; Norfolk Coast) and the British Geological Survey (BGS) Trunch borehole, Norfolk. Data are also presented from a section through the Scaglia facies exposed near Gubbio, Italian Apennines. Wherever possible the sampling interval has been one metre or less. Both the Chalk and Scaglia carbon-isotopic curves show minor positive excursions in the mid-Cenomanian, mid- and high Turonian, basal Coniacian and highest Santonian–lowest Campanian; there is a negative excursion high in the Campanian in Chalk sections that span that interval. The well-documented Cenomanian–Turonian boundary ‘spike’ is also well displayed, as is a broad positive excursion centred on the upper Coniacian. A number of these positive excursions correlate with records of organic-carbon-rich deposition in the Atlantic Ocean and elsewhere. The remarkable similarity in the carbon-isotope curves from England and Italy enables cross-referencing of macrofossil and microfossil zones and pinpoints considerable discrepancy in the relative positions of the Turonian, Coniacian and Santonian stages.

The oxygen-isotope values of the various Chalk sections, although showing different absolute values that are presumably diagenesis-dependent, show nonetheless a consistent trend. The East Kent section, which is very poorly lithified, indicates a warming up to the Cenomanian–Turonian boundary interval, then cooling thereafter. Regional organic-carbon burial, documented for this period, is credited with causing drawdown of CO2and initiating climatic deterioration (inverse greenhouse effect). Data from other parts of the world are consistent with the hypothesis that the Cenomanian–Turonian temperature optimum was a global phenomenon and that this interval represents a major turning point in the climatic history of the earth.
A new Arenig (Ordovician) graptolite fauna from the Kerman District, east-central Iran
Authors: Rickards R. B. , Hamedi M. A. , Wright A. J.
Published: May 2009

A single slab of silicified silty and cross-bedded mudstone from the Katkoyeh Formation, east-central Iran yieldsYutagraptuscf.mantuanusRiva which indicates a late Arenig age. The slab also bearsDictyonema ghodsiaesp. nov., regarded as the only unequivocally planktonic dendroid from post-Tremadoc strata. The sicula is surrounded by at least twelve vesicular bodies which constitute a raft of floats. These are the only certain floats yet identified in the Order Dendroidea, and one of very few cases known in the Class Graptolithina.
Plio-Pleistocene radiolarian biostratigraphy and palaeoceanography of the mid-latitude North Atlantic (DSDP Site 609)
Authors: Haslett Simon K.
Published: May 2009

Radiolaria were examined throughout the Plio-Pleistocene of Deep Sea Drilling Project (DSDP) Site 609. Eight radiolarian datum-levels (first and last appearances) were identified, some for the first time in the North Atlantic. The recognition of these datums allows correlation between the Atlantic, Pacific and Indian oceans, through a previously published zonal scheme (Johnson et al. 1989). Zones NR1 to NR11 were recognized, although some zones had to be combined (NR1–2 and NR8–10) due to the absence of some stratigraphically important taxa. The relative abundance distribution of the radiolarian palaeoceanographical proxy Didymocyrtis tetrathalamus indicated three cool phases (0/0.56–0.75 Ma, 1.2–1.33/1.69–1.86 Ma, and 2.14–2.32/3.73– > 4.1 Ma) interrupted by two relatively warm episodes (0.56–0.75/1.2–1.33 Ma and 1.69–1.86/2.14–2.35 Ma). These fluctuations in sea-surface temperature (SST) correspond with palaeoclimatic events indicated by other proxies (e.g. Foraminifera), such as the onset of Northern Hemisphere glaciation. This study illustrates the usefulness of radiolaria in North Atlantic stratigraphical and palaeoceanographical analysis.
Relationships between distributed and localized shear in the tectonic evolution of a Caledonian fold and thrust zone, northwest Ireland
Authors: Alsop G. I.
Published: May 2009

Broad zones of distributed shear operating through mid-crustal regions of orogenic belts may incorporate narrow horizons of intense localized deformation culminating in discrete, large magnitude displacements. The relative importance and relationship between distributed and localized shear are influenced by a variety of factors including lithological variation, pre-existing structural anisotropy, strain rate and migration of fluids. Rigorous structural analysis of lower amphibolite facies Dalradian metasediments in northwestern Ireland demonstrates that an early (D1) discrete ductile detachment was subsequently reactivated during distributed non-coaxial D2 deformation operating in a broad zone through the structural pile. Regional shear was directed towards the southeast and resulted in the generation and translation of kilometre-scale, isoclinal, recumbent sheath folds which close and face towards the transport direction. The D1 detachment is clearly folded around the hinges of these major folds, whilst on fold limbs it was reactivated and acted as a local décollement within the zone of distributed shear. Shear criteria along the detachment indicate a southeast-directed translation of the major folds, in sympathy with regional shear. A broad zone of D3 translation operating through the nappe pile resulted in coaxial refolding of large scale F2 folds by the D3 Ballybofey Nappe producing a complex fold interference pattern. Non-coaxial D3 deformation resulted in continued reactivation of local decollements, together with the initiation of east-southeast directed oblique thrusts and partial dismemberment of D2 folds. Detailed structural investigation allows concepts of distributed and localized shear to be evaluated and models of crustal deformation to be assessed.