bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dolerite-pegmatites from the Whin Sill near Barrasford, Northumberland
Authors: Randall B. A. O. 
Published: December 2009

SUMMARY
Four varieties of dolerite-pegmatite occurring in the Whin Sill at Barrasford are described. They are (1) normal pegmatite (NP) which is similar to the dolerite-pegmatites of Teesdale occurring as concordant lenticular lenses parallel to the sill’s upper surface and confined to the upper portion of the sill; (2) intrusive pegmatite (IP) a discordant vein containing autoliths of dolerite; (3) pegmatite (QP) below partially filled vesicles containing quartz and calcite and (4) pegmatite (PP) below amygdales completely filled with pectolite. QP and PP only occur below the amygdales and have the form of basal layers about 10mm thick. The pegmatites developed at an early stage in the consolidation of the sill and QP and PP had vesicular space above them. The filling of the vesicles took place later at lower temperature in two separate hydrothermal episodes yet there is an invarient relationship between pegmatite composition and amygdale fill. A chemical study of the four pegmatites, the normal dolerite (ND), intrusive basalt (IB) and aplite veins (IA) and their component minerals shows that all the rocks except PP lie on the normal differentiation trend of the Whin Sill.
Final consolidation temperatures as indicated by feldspar geothermometry are:- ND 1025°C; NP 713°C; IP 748°C; QP 572°C and IP 590°C. A temperature of feldspar equilibration of 460°C for PP supports the conclusion that PP is the metasomatic product of QP, altered by the solutions that deposited the pectolite. Some of the pectolite has been subsequently replaced by stevensite which has X-ray characteristics of heat treated (400°C) stevensite.
The biostratigraphic age of the Ordovician Skiddaw Group in the Black Combe Inlier, English Lake District
Authors: Rushton A. W. A. , Molyneux S.G. 
Published: December 2009

SUMMARY

Graptolites and acritarchs from several localities on the NW side of the Whicham Valley, Black Combe, show that the beds there (the Whicham Blue Slates of Helm 1970) are of late Arenig
Didymograptus hirundo
Biozone age. Acritarch floras show that the beds underlying the Borrowdale Volcanic Group on the SE side of the Whicham Valley are of latest Arenig age. Probable latest Arenig acritarchs have also been recorded from a tuffite at the base of the volcanic sequence of Millom Park. The possible age of this tuffite is discussed.
A ‘North-west Passage’ to the southern Zechstein Basin of the UK North Sea
Authors: Smith D. B. , Taylor J. C. M. 
Published: December 2009

SUMMARY
Sedimentary structures and variations of facies in late Permian marine carbonate rocks of the Raisby, Ford and Concretionary Limestone formations of Northumberland and Durham suggest that these rocks were formed on subaqueous slopes along the western margin of water at least 100m and perhaps more than 200m deep. This conflicts with the view expressed in some earlier works that Northumbria faced central parts of the Mid North Sea High, over which the later Permian marine strata were thought to be mainly of shallow water facies, and leads us to postulate the former existence of a north-south passage or channel across the high in late Permian time. The facies distribution of early Permian desert deposits is also consistent with the existence of a low-lying area here. The western margin of the postulated passage probably lay close to the present coastline and the scanty geophysical and borehole evidence suggests that its eastern margin may have lain perhaps 15 to 25 kilometres farther east. At least one other passage across the high has been identified previously.
Permo-Carboniferous mylonite formation in the Walls Boundary Fault system, Shetland
Authors: Roddom D. S. , Miller J. A. , Flinn D. 
Published: December 2009

SUMMARY

The Walls Boundary Fault system of Shetland is a major zone of transcurrent faulting which has been active on more than one occasion. It may include a northward extension of the Great Glen Fault. Evidence suggests that the latest major episode of movement, which resulted in the formation of a gouge filled fracture, is of Lower Jurassic age. Earlier movements suggested by lithological offsets across the fault are supported by the presence of bands and slices of mylonite within the fault zone. A mineralogical investigation of the mylonites shows that growth and recrystallisation of K-feldspar and white mica occurred during mylonitisation, and is responsible for partial overprinting of the potassium-argon age of the host rock.
40
Ar/
39
Ar stepheating spectra from two samples suggest that the phase of movement associated with the development of the observed ductile mylonites occurred during the latest Carboniferous or early Permian, although earlier movements are not ruled out.
Palynostratigraphy of the Scalby Formation (Middle Jurassic) of the Cleveland Basin, north-east Yorkshire
Authors: Riding J.B. , Wright J.K. 
Published: December 2009

SUMMARY
The precise age, Bajocian or Bathonian, of the Middle Jurassic Scalby Formation has proved controversial; a review of previous stratigraphical research on the Moor Grit Member and the overlying Long Nab Member is presented.
Palynofloras from the uppermost Long Nab Member of Newtondale, North Yorkshire, indicate a Bathonian age. Two palynomorph assemblages from the lowermost Long Nab Member from coastal exposures north of Scarborough have been re-examined and are suggestive of a late Bajocian to Bathonian age.
Přídolí graptolites from the Humevale Formation at Ghin Ghin and Cheviot, Victoria, Australia
Authors: Rickards R. B. , Garratt M. J. 
Published: December 2009

SUMMARY

Recent collecting has revealed three new graptolite-rich localities in the Humevale Formation above the Rice’s Hill Sandstone Member. Each indicates a Přídolí age for this part of the Humevale Formation, and reinforces earlier work by the authors attributing these
Baragwanathia
- yielding strata to the uppermost Silurian series. Two of the new localities, at Ghin Ghin (locs. B4 and B1A), have numerous specimens of
Monograptus
cf.
prognatus
Koren’ and
M
aff.
uniformis parangustidens
Jackson & Lenz respectively, whilst the locality at Cheviot (T2) contains abundant
M.
cf.
pridoliensis
Přibyl. Forms in any way referable to the last two species have not yet been recorded from the Australian continent before.
Lateral and vertical variations in pedogenesis and other early diagenetic phenomena, Middle Jurassic Ravenscar Group, Yorkshire
Authors: Kantorowicz J. D. 
Published: December 2009

SUMMARY
The effects of early diagenetic processes are widespread in shallow marine and non-marine (deltaic) sediments of the Ravenscar Group. These can be related to both lateral variations in ground water chemistry within the original depositional environment on the lower coastal plain, and to the introduction of sea water into the non-marine sediments and of fresh water into the marine sediments.

In the non-marine sediments lateral (catena) variations in soil profiles can be related to floodplain aggradation and abandonment. Near the major channel sands in the Saltwick Formation at Whitby West Cliff, a ganister and seatearth formed in elevated and well drained sediments that were frequently flushed with fresh water. In more distal floodplain areas, ground-waters were influenced by fresh water, but remained generally suboxic, as a result of which siderite cementation occurred. The influence of meteoric water is indicated by the isotopic composition of the cements that formed (
δ
13
C PDB −3.7 to −9.6 ‰,
δ
18
O PDB −6.0 to −8.5 ‰). Rhombic siderite cemented the sands, and siderite nodules formed in both sands and shales. Siderite spheruliths formed within more distal soil horizons (such as the Long Nab Member at Crook Ness) where bacterial processes dominated the supply of bicarbonate into the ground water, and in non-marine sediments on abandoned and subsiding delta lobes. Bacterial influence is reflected in the more negative carbon isotopic composition relative to that of the nodules (
δ
13
C PDB −16.2 ‰,
δ
18
O PDB −3.5 ‰). Sea water was introduced onto the floodplain locally, providing sulphate ions that were reduced and incorporated into the pyrite that precipitated in the siderite soil horizons.

In the marine Millepore Bed sediments at Yons Nab early diagenetic, possibly aragonite, fringes formed on bioclasts and ooliths. These were subsequently deformed by the weight of overburden following renewed progradation. Grain-to-grain contact dissolution and kaolinite precipitation occurred as the fresh groundwater invaded these marine carbonates from the prograding delta above.
Enigmatic boulders and syn-sedimentary faulting in the Carboniferous Limestone of the Isle of Man
Authors: Quirk D. G. , Ford T. D. , King J. A. , Roberts I. L. , Postance R. B. , Odell I. 
Published: December 2009

SUMMARY
A small area of Lower Carboniferous (early Brigantian) Limestone in a coastal inlet in the south of the Isle of Man contains boulders of pale bioclastic limestone lying upon and overlain by thin undulating beds of dark calcareous mudstone. It is shown that during deposition of this facies the sea bed dipped towards a syn-sedimentary fault on the north side of the inlet where approximately 3m of normal movement occurred prior to its deposition. 50m to the south, a limebank developed above the crest of a small rollover anticline in the hanging wall of the fault. Instability of this structure led to an episode of sediment collapse. A density flow, containing blocks and boulders of pale limestone, slid northwards over black muddy sediments that were accumulating in the deeper water close to the fault. Both lithologies also show evidence of soft sediment deformation. This study shows that carbonate boulder beds and other fault-related structures can be extremely local in nature.
A revised lithostratigraphy for the Lower and Middle Lias (Lower Jurassic) east of Nottingham, England
Authors: Brandon A. , Sumbler M. G. , Ivimey-Cook H. C. 
Published: December 2009

SUMMARY
Recent geological mapping by the British Geological Survey (BGS) of an area near Fulbeck, north of Grantham, together with examination of cored site investigation boreholes, has revealed the detailed stratigraphy of the lower part of the Lias Group (“Lower and Middle Lias”) in the region east of Nottingham for the first time. The stratigraphical classification used by previous authors is inadequate in several ways, and a new scheme is proposed. Under this new scheme, the beds between the base of the Lias Group and the base of the Marlstone Rock Bed are formally divided into two formations of approximately equal thickness. The Scunthorpe Mudstone Formation, forming the lower part of the sequence, is divided into five members for which Borehole F/B5, sunk on Fulbeck Airfield, is defined as the type section; the cores are held by BGS. These members consist alternately of mudstone with numerous limestone beds, and mudstone with few limestone beds. Many widespread limestone beds have been mapped and informally named. The overlying Brant Mudstone Formation consists of mudstone with common nodule beds. It has not been formally subdivided, although several marker beds have been mapped. Geophysical borehole log correlation and limited fieldwork show that the sequence extends virtually unchanged into the Vale of Belvoir to the south-west. Farther afield, the two formations and some component members and even some beds can be recognized throughout the area of the East Midlands Shelf.
The Fossil Sandstone — a shallow marine sand wave complex in the Namurian of Cumbria and North Yorkshire, England
Authors: Brenner R. L. , Martinsen O. J. 
Published: December 2009

SUMMARY

The Fossil Sandstone represents marine sand deposition during the Namurian E2
a(ii)
marine cycle on the Askrigg Block in northern England. Sand was shaped into sand waves in an offshore setting at least 10 km from the synchronous shoreline. These sands and associated muds are preserved in five lithofacies: 1) shale, 2) interstratified sandstone and shale, 3) wavy-laminated sandstone, 4) tabular cross-bedded sandstone, and 5) mottled sandstone. Delta progradation followed by transgressive submergence was the most likely primary basinward sand-moving mechanism. Wavy-laminated sandstone and interstratified sandstone and shale represent a sand buildup that formed as a result of marine reworking of deltaic sands. Periodic increases in current intensity caused the formation and eastward migration of sand waves on the higher portions of the sand buildup. Sand waves are represented by cross-bedded sandstone with easterly-dipping tabular foresets separated by gently dipping to nearly horizontal erosional surfaces. These foreset beds contain crinoid and brachiopod fragments and the lowermost erosional surface at each locality is overlain by a thin shale-chip and fossil hash lag. Bioturbated surfaces represent upper portions of sand bodies subject to biogenic activity between high-energy storm events or as the bodies became moribund.

The Fossil Sandstone is an example of sand deposition in a mud-dominated marine shelf setting. In some, but not all aspects, it is similar to some of the Upper Jurassic and Upper Cretaceous sandstones in the Western Interior of North America.
Stratigraphy of the Worston Shale Group (Dinantian), Craven Basin, north-west England
Authors: Riley N. J. 
Published: December 2009

SUMMARY

The Worston Shale Group of Earp
et al.
(1961) is made up of four formations: the Clitheroe Limestone, Hodder Mudstone, Hodderense Limestone and Pendleside Limestone. Within these formations fifteen members are defined: the Thornton Limestone, Coplow Limestone, Peach Quarry Limestone, Bellman Limestone, Limekiln Wood Limestone. Phynis Mudstone, Whitemore Limestone, Hetton Beck Limestone, Leagram Mudstone, Buckbanks Sandstone, Embsay Limestone, Rain Gill Limestone, Chaigley Limestone, Twiston Sandstone and Rad Brook Mudstone. A particular bed within the Hodder Mudstone Formation, the Dunbarella Bed, is also recognised. Four unconformities are recognised. The most widespread is at the base of the Hodder Mudstone Formation; the others, which are more restricted, occur at the base of the Embsay Limestone Member (and equivalents), at the base of the Twiston Sandstone Member and at the base of the Pendleside Limestone Formation. Diagnostic Viséan foraminifera and conodonts first enter within the basal part of the Hodder Mudstone Formation, suggesting that the Tournaisian-Viséan boundary lies much higher than previously supposed. All the Dinantian stage boundaries in the Arundian to Asbian interval have been re-correlated. The Craven Basin is thought to have been underlain by an asymmetric graben within the pre-Carboniferous basement and the depositional history of the basin to have resulted from a combination of both syndepositional tectonics and eustatic processes. Consequently, the basinal sediments portray a transition from carbonate shelf to slope (Gawthorpe 1987), involving a change during deposition of the Clitheroe Limestone and Hodder Mudstone formations from shallow-water carbonates, generated within the basin, to deep-water hemi-pelagic sediments with limestone turbidites fed from the surrounding carbonate shelves and platforms. Intermittent supply into the basin of terrigenous sand and reworked faunas is related to the emergence and erosion of the surrounding areas.
Depositional environments and palaeogeography of the Station Quarry Beds (Brigantian), Derbyshire, England
Authors: Gutteridge P. 
Published: December 2009

SUMMARY
The Station Quarry Beds were deposited during a transgressive episode at the beginning of the Brigantian in a structurally controlled basin on the Derbyshire carbonate platform. The initial flooding of this basin was marked by the deposition of sediment reworked from subtidal, shoreface and back barrier intertidal sediments on the karstified and calcretised surface of the Bee Low Limestones. As sea level continued to rise, low energy, sub-wave-base conditions, interrupted by occasional storms, were established within the intrashelf basin. The generally low-energy environment is attributed to the sheltered setting of the intra-shelf basin rather than water depth. The near normal to fully marine salinity, together with the well-oxygenated conditions of deposition, suggest that the intra-shelf basin was probably connected to a larger body of fully marine water.
The correlation of the Speeton Shell Bed, Filey Bay, Yorkshire, to an oxygen isotope stage
Authors: Wilson Sandra J. 
Published: December 2009

SUMMARY
The Speeton Shell Bed is a Quaternary estuarine deposit approximately 2m thick. It is overlain by late Devensian till that, in places, contains thin rafts of Basement Till.

Amino acid ratios of
Macoma balthica
shells allow correlations to be made with the well dated sequence of oceanic oxygen isotope stages. These suggest that the shell bed was deposited in Oceanic Stage 7, and that the Basement Till was probably deposited in Oceanic Stage 6. In view of the recent controversy over the status of the type Wolstonian in the Midlands the Basement Till seems to be the most likely remaining representative of the Wolstonian Stage glaciation in Britain.

There is now considerable evidence to separate an earlier (Oceanic Stage 7) interglacial from the classic Ipswichian (Oceanic Stage 5e) in Britain. This casts some doubt on the reliability of pollen analysis for exact dating, as assemblages from analogous (early temperate) zones of the two interglacials are apparently indistinguishable.
Ryazanian to Barremian mineral stratigraphy of the Speeton Clay in the UK southern North Sea Basin
Authors: Knox R. W. O’B. 
Published: December 2009

SUMMARY
Analysis of a late Ryazanian to early Barremian Speeton Clay section in a cored North Sea borehole has revealed a pattern of changing mineral composition that is believed to represent changes in sea-level, climate and palaeogeographical configuration. The lithological sequence can be broadly matched with that of the onshore Speeton Clay section, with precise onshore-offshore correlations being provided by sporadic bentonite layers. Because the factors controlling changes in the mineral assemblages are likely to have been of regional effect, the mineral stratigraphy established for the borehole sequence may prove to be of use not only in correlating within the North Sea marine realm, but also in relating the marine sequences to the paralic to non-marine Wealden sequences of southern England.
Bentonites from the Horton Formation (Upper Silurian) of Ribblesdale, Yorkshire
Authors: Romano M. , Spears D. A. 
Published: December 2009

SUMMARY

Previously unrecorded K-bentonites are identified from the lower part of the Horton Formation (Ludlow) in Horton in Ribblesdale. The thickest (14 cm) of these is unusual in that it contains a distinctive internal stratigraphy which allows unambiguous correlation with sequences on both limbs of the Studrigg-Studfold Syncline. A further feature of the bed is that a lower nodular part preserves shards and vesicles. Illite (1M polytype) is the major component of the bentonite. Illitisation of a precursor smectite took place during diagenesis, which approached the anchizone stage, with a percentage expandability of less than 5%. Quartz, albite, chlorite and muscovite (2M
1
, polytype) are also present; these are the detrital minerals that dominate the associated siltstones. The siltstones appear to have attained a higher diagenetic level than the bentonite because they incorporate detritus derived from higher grade source rocks. Immobile trace elements in the bentonite indicate a rhyodacite/dacite composition, possibly a high-K lava type within the arc lava field. Although carbonate nodules are present in the bentonite, diagenetic stages in the chemical evolution are not preserved.
A check list of brachiopods from Treak Cliff, Derbyshire, with reference to other Dinantian (Lower Carboniferous) localities
Authors: Brunton C. H. C. , Tilsley J. W. 
Published: December 2009

SUMMARY
As an aid to the identification of brachiopods from the Asbian (Lower Carboniferous) reef environments in the northern British Isles, 125 species known from Treak Cliff, Derbyshire, are listed and characterised. Their presence at other localities is recorded. A brief survey of literature related to Treak Cliff is provided.
Karstification and pedogenesis on a late Dinantian carbonate platform, Anglesey, North Wales
Authors: Davies J. R. 
Published: December 2009

SUMMARY

The late Dinantian (Lower Carboniferous) carbonate succession on Anglesey, North Wales, comprises over 20 transgressive/regressive shoaling upwards cycles. Cycle tops are marked by distinctive hummocky surfaces, interpreted as palaeokarstic, commonly overlain by green bentonitic clay palaeosols with fossil rootlets, and locally by red
terra-rossa
clays. Limestones immediately below the karstic surfaces display structures and fabrics typical of calcretes, including rhizoliths, calcrete ooids, micrite pellets, micritised grains and micritic vadose cements. These pedogenically altered limestones are commonly capped by laminar calcrete crusts of accretionary origin. The effects of contemporary brecciation and growth of microspar further contribute to a variety of emergent profiles developed at minor cycle tops. Profile development was in two stages. During the early syn-lithification stage, closely following emergence, plants and soil-dwelling faunas colonised unconsolidated platform carbonates. Micritic coatings and cements were deposited and wind-blown volcanic fines accumulated at the surface. During the ensuing post-lithification stage, roots and downward percolating rain waters could no longer penetrate the underlying case-hardened carbonates. Micrite was deposited as sheets at the soil/rock interface, building laminated crusts rich in rhizoliths, whereas elsewhere, or at other times, sub-soil dissolution led to the formation of the characteristic karstic morphology. Preferential dissolution within broad karstic depressions generated localised pockets of reddened insoluble residues. Brecciation re-exposed lower parts of some profiles to secondary phases of calcretisation and, with concomitant dissolution and downward infiltration of clay palaeosol material, created deep, regolith-like rubbly profiles within which there was extensive replacive and displacive growth of microspar.
Late Triassic and early Jurassic biostratigraphy of the Felixkirk Borehole, North Yorkshire
Authors: Ivimey-Cook H. C. , Powell J. H. 
Published: December 2009

SUMMARY
The Felixkirk Borehole proved late Rhaetian to Aalenian strata in the western part of the Cleveland (Yorkshire) Basin. The biostratigraphy deduced from the specimens recovered is presented and linked with previously reported data. Early Jurassic sedimentation in the Cleveland Basin is briefly discussed with reference to the Acklam boreholes which are located close to the southern margin of the Basin.
New evidence for the origin of distinctive quartz overgrowth textures in the Raisby Formation (Zechstein carbonate), north-east England
Authors: Benzagouta M. S. , Lee M. R. 
Published: December 2009

SUMMARY
Petrographic study of a dolomitic sandstone within the Upper Permian Raisby Formation in Northumberland has revealed distinctive quartz overgrowth textures on detrital sand grain surfaces. These textures, comprising discontinuous ridges of authigenic quartz in a regular pattern, have previously been interpreted to be the result of replacement of quartz by carbonate crystals. However, rare textural inter-relationships between dolomite and quartz in this sandstone demonstrate that the ridges result from the growth of authigenic quartz along narrow pore spaces between dolomite crystals. This process may have important consequences for the petrophysical characteristics of mixed carbonate - siliciclastic reservoir rocks.