bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Bail Hill Volcanic Group: alkaline within-plate volcanism during Ordovician sedimentation in the Southern Uplands, Scotland
Authors: Phillips E. R. , Smith R. A. , Floyd J. D. 
Published: November 2011

AbstractThe Bail Hill Volcanic Group (Caradoc) represents the largest, single volcanic complex exposed within the Ordovician turbidite succession of the Northern Belt in the Southern Uplands of Scotland. The group comprises a heterogeneous sequence of submarine lavas, volcaniclastic and intrusive rocks (up to 2 km thick), and crops out in a small area (c. 4 km2) around Bail Hill, north of Sanquhar. The Cat Cleuch Formation (older) is dominated by a sequence of autobrecciated basaltic lavas which contain large, zoned diopsidic clinopyroxene. The overlying Peat Rig Formation comprises a more mixed sequence of plagioclase-amphibole-phyric lavas, volcaniclastic rocks and contemporaneous volcaniclastic sedimentary rocks. The Cat Cleuch and lower part of the Peat Rig formations are cut by a vent breccia, the Bught Craig vent breccia, which formed part of the feeder to the upper part of the Peat Rig Formation. The Bail Hill volcanic rocks are alkaline in character, ranging from alkali basalt to trachyandesite in composition, possessing trace element characteristics and enrichment patterns typical of oceanic within-plate basalts. The Bail Hill Volcanic Group, although geochemically distinct, forms part of a mixed assemblage of tholeiitic and alkaline withinplate lavas within the Southern Uplands which are of broadly similar age, some of which are intercalated within the greywacke sandstone sequence. This assemblage clearly indicates that a period of extension and within-plate volcanism occurred during the early stages of the development of the Southern Uplands sedimentary basin.
A redescription of the Carboniferous arachnid Plesiosiro madeleyi Pocock, 1911 (Arachnida: Haptopoda)
Authors: Dunlop Jason A. 
Published: November 2011

AbstractPlesiosiro madeleyi Pocock, 1911, the monotypic representative of the fossil order Haptopoda Pocock, 1911 from the British Middle Coal Measures (Upper Carboniferous, Westphalian B) of Coseley, Staffordshire, is redescribed. A specimen from Sparth Bottoms, Lancashire is not a Plesiosiro and is referred to Arthropoda incertae sedis. Plesiosiro was probably a predator, having tooth-like projections on the femora for prey capture, and shows adaptations of the limbs for crawling in narrow spaces. The uncertain nature of the chelicerae, eyes and respiratory organs makes resolving the phylogenetic position of Plesiosiro difficult, though Haptopoda deserves its status as a separate order. Plesiosiro resembles both cythophthalmid and trogulid opilionids. Its broad prosoma–opisthosoma junction could be interpreted as a synapomorphy for Plesiosiro + Opiliones, but this character is not unique to these orders. Alternatively, Plesiosiro has a large, ventral opisthosomal sclerite. This is interpreted here as a genital operculum, a synapomorphy for Tetrapulmonata, and Plesiosiro is tentatively referred to this clade. Based on the synapomorphies of a divided sternum and subdivided telotarsi a relationship of the form: (Plesiosiro (Amblypygi (Thelyphonida + Schizomida))) is proposed.
A new large lamniform shark from the uppermost Gearle Siltstone (Cenomanian, Late Cretaceous) of Western Australia
Authors: Siverson Mikael 
Published: November 2011

AbstractAn association of 100 teeth and 15 vertebrae from a large, lamniform shark, is described from the uppermost part of the Gearle Siltstone in the Giralia Anticline, Southern Carnarvon Basin, Western Australia. The material represents a new genus and species: Cardabiodon ricki. The taxon is referred to the new family Cardabiodontidae on the basis of its dental formula and uniquely oversized lower lateroposterior teeth. Other characteristic features include a strong dignathic heterodonty and the presence of four anterior and approximately 14 lateroposterior toothfiles in both the upper and lower jaw. The size of the recovered vertebral centra indicates that the shark measured at least 5 m in total length. The species had a wide but possibly patchy distribution with additional occurrences in England and Kazakstan, where it is present in strata of Cenomanian age. Cardabiodon shares several key dental characters with Parotodus, known from Oligocene–Pliocene deposits. The latter taxon was previously grouped with the ‘mega-toothed’ sharks of the genera Otodus and Carcharocles, but is here reassigned to the Cardabiodontidae.The nominal species Cretalamna woodwardi from the middle or late Cenomanian of southern England, is designated as the type species of the new genus Dwardius. The coeval nominal species Pseudoisurus tomosus from the Saratov region in Russia, is based on material that almost certainly includes C. ricki and/or D. woodwardi. Designation of a lectotype for P. tomosus and its proper documentation would probably allow either C. ricki or D. woodwardi to be synonomised with the older name P. tomosus. There is, however, a strong possibility that the syntypes of P. tomosus are lost. Until they are found, redescribed and compared carefully with the type material of C. ricki and D. woodwardi, P. tomosus is a name of doubtful application and therefore referred to as a women dubium
Late Miocene marine fossil-rich, rock-fall, avalanche, mud-flow and debris-flow deposits adjoining and near the western margin of the Tawhero Basin, outer forearc North Island, New Zealand
Authors: Neef G. 
Published: November 2011

AbstractA late Miocene marine, massive fossil-rich, rock-fall/avalanche deposit, >42 m thick (base unexposed) and mud-flow and debris-flow deposits, commonly 0.2–4 m thick, are present adjoining and near to either margin of a 12 km long segment of the NE-trending Waihoki Fault/fault zone, near Pongaroa, North Wairarapa, North Island, New Zealand. The Waihoki Fault/fault zone lies in the outboard part of the onland part of the forearc. It forms the western margin of the Tawhero Basin, a forearc basin overlying a subducting Pacific plate, during 6.6–25 Ma. The basin had a partly dextral transpression history (especially in the Late Miocene) but the amount of dextral displacement along the Waihoki Fault/fault zone is unknown. It is likely that lightly indurated fossil-rich, rock-fall, mud-flow and debris-flow deposits were derived from the tops of fault slivers that were pushed upwards along the Waihoki Fault/fault zone during dextral faulting to reach the neritic zone.
Exceptional REE-enrichment in apatite during the low pressure fractional crystallisation of alkali olivine basalt; an example from the British Tertiary Igneous Province
Authors: Preston R.J. , Hole M.J. , Still J. 
Published: November 2011

AbstractThe Cnoc Rhaonastil dolerite boss on Islay, NW Scotland represents a body of alkali-olivine basalt magma which differentiated at low pressure and in situ, from dolerite through teschenite to minor nepheline-syenite. The syenites occur as isolated pods and pegmatitic schlieren within the leucodolerite, and have an exotic mineralogy including Zr-aegirine, Zr-arfvedsonite, Ca-catapleiite, zirconolite and aenigmatite. Fluor-apatite occurs as an accessory phase in the dolerite, but becomes more abundant within the teschenite and syenites. Total REE contents within apatites in the dolerites are typically low (σREE = 0·57–3·21 wt.% oxide), the highest REE contents occurring in irregular, deuterically altered rims and internal patches. The REE-enriched rims also have slightly elevated SiO2 contents at 0·81–0·95 wt.%, suggesting that the substitution scheme Ca2++P5+ ⇔ REE3++Si4+ was operating. These apatites have up to 0·08 wt.% Cl and 3·7 wt.% F, with most being almost pure end-member fluor-apatite. The majority of the teschenite apatites show the least REE-enrichment (σREE = 0·27–0·45 wt.%), coupled with low Na (<0·12 wt.%) and low SiO2 (<0·39 wt.%) contents. However, within the syenites two distinct populations of apatite exist. The first, most common, variety consists of unzoned, low-REE apatites (max. 3·1 wt.% σREE, again in irregular rims and patches), whereas the second variety is often complexly zoned, and has variably enriched zones up to a maximum σREE content of 42 wt.%; this is by far the most REE-enriched natural fluor-apatite so far reported from the British Isles. The REE-enriched zones are often less than 3 μm wide, and have Na content up to 5·4 wt.% Na2O, implying that the substitution scheme Na+ + REE3+⇔2Ca2+ dominated over the more typical scheme involving Si4+ which operated in the dolerites and teschenite. Other zones are either variably enriched in Y (up 2·1 wt.% Y2O3) or Th (up to 0·85 wt.% ThO2). However, there is no correlation between Y and REE contents, suggesting that crystallographic factors were involved in apatite Y and REE partitioning. The REE-rich apatites have very low Cl content (<0·04 wt.%), but high F concentrations (<2·8 wt.%). It is believed that these strongly enriched apatites crystallised under disequilibrium conditions from isolated, variably REE-enriched domains, within the fluid-rich residual syenitic magma. These domains may have been generated by the prior crystallisation of monazite, Ca-catapleiite or zirconolite, which can be found as small inclusions within albite and interstitial analcime. The dynamic process of slumping of the denser teschenite back into the leucodolerite crystal mush is believed to have played an important role in the release of deuteric fluids and the concentration of residual magmas.
Dionidid and raphiophorid trilobites from the middle Ordovician (Viruan Series) of Jämtland, central Sweden
Authors: Månsson Kristina 
Published: November 2011

AbstractDionidid and raphiophorid trilobites are described from the middle Ordovician (Viruan Series) of Jämtland, central Sweden. The family Dionididae is represented by one genus,DionideBarrande, 1847, and the family Raphiophoridae by five genera,AmpyxDalman, 1827,AmpyxellaDean, 1960,AmpyxoidesWhittington, 1965,CnemidopygeWhittard, 1955 andLonchodomasAngelin, 1854. Seven species are described and discussed. Three of these are new:Dionide jemtlandicasp. nov.,Ampyxoides minorsp. nov. andLonchodomas striolatussp. nov.. The majority of the trilobites described are from the Andersön Shale, equivalent to theH. teretiusculus, N. gracilisand lowermostD. multidensZones (upper Llanvirn and lower Caradoc), and the Örån Shale, equivalent to the lowerD. dinganiand the uppermostD. multidensZones (middle Caradoc). Meraspid and early holaspid material ofD. jemtlandicais described.
Geochronological evidence for phased volcanic activity in Fife and Caithness necks, Scotland
Authors: Macintyre R. M. , Cliff R. A. , Chapman N. A. 
Published: November 2011

AbstractIn an attempt to establish a chronology for volcanic neck emplacement and so elucidate petrogenesis, isotopic studies have been carried out on various cumulate inclusions, blocks and megacrysts which occur chiefly in association with tuffs infilling several Scottish vents. K-Ar ages of 13 samples of low-pressure cumulate minerals (biotite, hornblende and pyroxene) from necks in East Fife indicate crystallisation at shallow depth at 314 Ma. U-Pb analyses of zircons are concordant at 318 Ma suggesting they are also members of this suite and their formation is penecontemporaneous with the Namurian volcanic activity which is welldocumented stratigraphically. By 295 Ma crystallisation of anorthoclase megacrysts had been completed, perhaps from the fractionated residuum. An eruption from considerable depth (within the stability field of garnet precipitation) then broke through to the surface bearing high-pressure megacrysts. This penetrated and disrupted the early cumulates carrying them to the surface and producing the diverse vent assemblages. K-Ar dating of basanites suggest that the Duncansby Ness neck in Caithness was emplaced around 270 Ma in the early Permian. For two Fife necks the balance of evidence favours an age of 290 Ma (Stephanian) for this final explosive activity associated with vent formation.
Stratigraphy of a flysch succession: the Ordovician of W Nithsdale, SW Scotland
Authors: Floyd James D. 
Published: November 2011

AbstractA thick Ordovician marine flysch succession including greywackes, conglomer- ates, siltstones and shales occurs in West Nithsdale in the Northern belt of the Southern Uplands. Five new formations of Caradoc and ?Ashgill age are defined based mainly on petrographical and lithological evidence. The proposed correlation with areas up to 80 km distant to the SW, emphasises the persistent nature of the greywacke formations in the Southern Uplands when traced along strike. It is demonstrated that the main inliers of black shale in the Northern belt cannot be simple anticlines but are closely associated with large strike faults. The position of the investigated flysch succession in the accretionary prism model for the development of the Southern Uplands during the evolution of the Caledonides is indicated and its significance assessed.
Palaeodrainage of the southern margin of the Caledonian mountain chain in the northern British Isles
Authors: Simon J. B. , Bluck B. J. 
Published: November 2011

AbstractLower Old Red Sandstone drainage of the Caledonian mountain chain in the northern British Isles converged in the region of the present North Channel between Scotland and Ireland. Calculations of possible catchment area of this drainage network suggest a major river systemc. 530 km in length comparable to parts of the present day drainage network of the Himalayas. Evidence from the Lower Old Red Sandstone sedimentary assemblages in Northern Ireland and Scotland indicates that tributaries flowed NE and SW parallel to the Caledonian mountain front. These tributaries joined a trunk stream which flowed southward from present western Scotland through the southern part of the present Inner Hebrides region, and on through the region of the present North Channel and terminated in the contemporaneous Devonian sea. The coastline of this sea stretched E-W across southern Britain.The essential drainage system established in Lower Old Red Sandstone times became re- established in Upper Old Red Sandstone times, but with a channel network with palaeoflow to the NE in Scotland. This probably joined a southerly flowing trunk stream in the North Sea region, possibly parallel with the western Scotland-Irish Sea drainage.
Review of the trilobites from the Middle Ordovician Barr Group, Girvan district, Scotland
Authors: Tripp R. P. 
Published: November 2011

AbstractCollections from the Barr Group (late Llanvirn to early Caradoc) of the Girvan district are described and occurrences of all trilobites from both the Barr and Albany groups are listed and their frequencies recorded. The close relationships with North American faunas are emphasised, and three Girvan and North American species are considered synonymous. One new species is described,Bevanopsis phyllisae. Pandaspinapygais considered a junior subjective synonym ofAcanthoparypha. The possibility thatAlwynulusmay be an aberrant staurocephalid is discussed.Growth stages of several genera are illustrated; some show unexpectedly large differences in size and morphology in comparison with North American silicified species at the same general stage of development.
The diamond deposits of the Mandala basin, SE Guinea, West Africa
Authors: Sutherland Donald G. 
Published: November 2011

AbstractThe Mandala drainage basin lies in the central part of the West African craton immediately to the south of the regional watershed. There has been frequent kimberlite dyke intrusion in the basin. The kimberlites range in grade from apparently barren to having a high diamond content. The presence of other undiscovered kimberlites can be inferred from the distribution, chemistry and abundance of kimberlite satellite minerals and variations in diamond size and character. Secondary diamond deposits are widespread with the main concentrations in the present and former Mandala valley bottoms. Tributaries have lower diamond contents. There are systematic variations in the alluvial diamond characteristics which can be explained in terms of diamond sources as well as transport of the diamonds away from those sources. The occurrence of the secondary diamond deposits is explained by the form and distribution of the primary sources, the nature of the drainage network and the long-term evolution of the drainage basin. Since the Pliocene or Early Pleistocene the Mandala has been rejuvenated with incision of the main channel by up to 26 m. This incision has led to flushing of the tributaries and storage of sediment, including diamonds, in the principal channel.
Cretaceous foraminiferal morphogroup distribution patterns, palaeocommunities and trophic structures: a case study from the Sergipe Basin, Brazil
Authors: Koutsoukos Eduardo A. M. , Hart Malcolm B. 
Published: November 2011

Foraminiferal studies have been used in palaeo-environmental reconstructions of the marine Cretaceous succession (upper Aptian to Maastrichtian) of the Sergipe Basin, in northeastern Brazil. The foraminiferal assemblages show broadly three types of response to changes in environment: (1) variations in morphotypes of the taxa present; (2) changes in specific and generic diversity; and (3) changes in relative abundance.Twelve palaeocommunities, characterised by the relative dominance of the major foraminiferal groups, can be recognised in the succession. Their palaeoenvironmental distribution is proposed as a model with reference to the Sergipe Cretaceous sequence.An intimate relationship is inferred among foraminiferal association distribution patterns, trophic structures (community feeding strategy, dwelling habits, substrate niche patterns) and water-mass conditions (depth-related in part). It is suggested that the distribution patterns may be a direct response of the functional adaptive morphology of the foraminiferal tests to individual characteristics of behavioural structure (preferential dwelling microhabitat and trophic strategy versus environment). The approach is a simple, yet very powerful tool, for the interpretation of foraminiferal palaeocommunities and palaeoceanographic research. It may also permit interpretation of palaeocommunity strategies in terms of adaptation rate and selection response (i.e. “r-selection” versus “k-selection”) to variable environmental conditions.
Agnostid trilobites from the Lower Ordovician of southern Sweden
Authors: Ahlberg Per 
Published: November 2011

AbstractAgnostid trilobites are described from the Lower Ordovician (Oelandian Series) of Öland, Östergötland, Västergötland and Närke, southern Sweden. In addition, a few agnostids are described from the Ceratopyge Limestone (upper Tremadoc) of Scania (Skåne), the southernmost province of Sweden. 24 species (of whichGalbagnostus nericiensisis new), assigned to four genera, are described or discussed. Species ofGeragnostusandArthrorhachisdominate numerically. Also recorded locally are species ofGalbagnostusandLeiagnostus. Most species have a markedly restricted vertical distribution, and many species appear to have a sufficiently short range to be of value in stage- and zone-level correlation. Agnostids are represented almost throughout the Lower Ordovician of southern Sweden, but they have not been recorded from the Tremadocian “Dictyonema” and Ceratopyge Shales, nor from the upper Holen Limestone (upper Kundan Stage). In the Ordovician of Baltoscandia, agnostids are largely restricted to the Central Baltoscandian Confacies Belt; they are very rare or absent in the adjacent belts to the east and in the graptolitic shales of the Scanian Confacies Belt.
Ashgill greywackes in the Southern Uplands of Scotland: an extension of the Ordovician succession in the Northern Belt
Authors: Floyd J. D. , Rushton A. W. A. 
Published: November 2011

ABSTRACTIn the Southern Uplands of Scotland, the youngest greywackes along the SE margin of the Northern Belt are shown to be of Ashgill age. Mudstones interbedded with the dominantly quartzose greywackes of the Shinnel Formation have yielded Dicellograptus anceps, indicating the anceps Biozone. In addition, the newly-defined mafic-rich Glenlee Formation, lying to the SE of the Shinnel Formation in the New Galloway-Moniaive area, has yielded fossils of the pacificus Subzone, the upper subzone of the anceps Biozone. Since the oldest greywackes of the Central Belt, separated from the Northern Belt by the Orlock Bridge Fault, are now confirmed as of basal Silurian acuminatus Biozone age, the stratigraphical break across the Orlock Bridge Fault is greatly reduced, lending support to the ‘single terrane’ model for the Southern Uplands.
Taphonomy of plant fossils from the Viséan of East Kirkton, West Lothian, Scotland
Authors: Brown R. E. , Scott A. C. , Jones T. P. 
Published: November 2011

ABSTRACTThe Viséan sequence at East Kirkton contains abundant plant fossils which show a wide range of preservation states. Most of the plant fragments are allochthonous, but stigmarian rootlets are foundin situat the top of the sequence and form mats near the base, where they are preserved in cherts. Axes have commonly been reworked within tuffs at the base. The majority of the plants are preserved as fragmentary compressions, although mineral replacement of the organic matter has occurred in some places. A number of woody axes which have been permineralised by phases of calcite and silica are found in the limestone and tuffs of the sequence. These axes often show complex mineralisation patterns and can occur at the centre of stromatolitic nodules. Some are well preserved and appear to have been permineralised rapidly whereas others show evidence of decay prior to calcite growth or degradation after stromatolite developed. Fusain (fossil charcoal) is abundant in the sequence, in addition to fusain transition fossils caused by partial charring, which suggests the occurrence of palaeowildfires in the area. The plant fossils have been assigned to a number of categories (some of which are new), based on their varied preservation states.