bluuebunny/crossref_metadata_2025 huggingface dataset:
The correlation of the Speeton Shell Bed, Filey Bay, Yorkshire, to an oxygen isotope stage
Authors: Wilson Sandra J.
Published: December 2009

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

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

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

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

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

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

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.
The age of the Easington Raised Beach, County Durham
Authors: Bowen D. Q. , Sykes G. A. , Smith D. B.
Published: December 2009

The gravel of the Easington Raised Beach rests on a bevelled platform of Magnesian Limestone at about 32m above O.D. at the head of Shippersea Bay, Easington. It appears to underlie glacial drifts of supposed late Devensian age and contains marine shells with a radiocarbon age exceeding 38,000 years.

Calculations of amino acid ratios in molluscan shells from the deposit have shown that it can be ascribed to an inter-glacial high sea level event (Oxygen Isotope Stage 7) between the Hoxnian and the Ipswichian.
Lower Cretaceous calcareous nannofossil biostratigraphy of a North Sea borehole: implications for Boreal Cretaceous stratigraphy
Authors: Bralower T. J.
Published: December 2009

The calcareous nannofossil stratigraphy of a borehole from the southern North Sea has been investigated in detail. The results are used to evaluate the potential of previously proposed nannofossil marker species and to examine proposed correlation of Boreal nannofossil, and other fossil zones, with stage stratotype sections located in southern Europe. The results support the relative order of nannofossil events proposed in previous zonations based on studies of land sections. Certain intervals of continuous fossiliferous section in the borehole, such as the Upper Hauterivian, complement studies of land sections where these intervals are not complete. The observation of certain predominantly Tethyan nannofossil taxa, including
Cruciellipsis cuvillieri, Speetonia colligata
and
Tubodiscus verenae,
whose ranges have not been investigated in detail in Northern European sections, calls into question previous correlations of fossil zonations with chronostratigraphic boundaries. In particular, both the Valanginian/Hauterivian and Hauterivian/Barremian boundaries defined by ammonites may have been somewhat inaccurately placed in the North Sea region as a result of indirect correlations and secondary markers. The Hauterivian/Barremian boundary may have been placed some 4m too high in the Speeton section, and the Valanginian/Hauterivian boundary 7 to 11m too low at the same location. The results are by no means conclusive, but illustrate that further detailed studies of Tethyan nannofossil markers in Boreal sections are warranted.
The sedimentology of the Middle and Upper Border groups (Viséan) in the Stonehaugh Borehole, Northumberland
Authors: Smith S. A. , Holliday D. W.
Published: December 2009

A sedimentological study has been made of the core from the Stonehaugh Borehole, which proved strata from the Viséan Middle and Upper Border groups of central Northumberland. Much of the Middle Border Group was deposited in a fluvially dominated delta, in interdistributary bays, minor mouth bars, crevasse splays and backswamps. However, a significant part of the group was deposited under more arid conditions in temporary lakes and on muddy floodplains. Sediments of the Upper Border Group were more tidally influenced, being deposited on tidal flats and as bay in-fills. All of these associations are locally cut by major fluvial and delta distributary channels. The transition from fluvial to tidally influenced sedimentation close to the Middle/Upper Border Group boundary is broadly coincident with a period of volcanism, footwall uplift and changing palaeogeography associated with the transition from extensional to thermal relaxation subsidence in the Northumberland Trough.
The Dinantian stratigraphy of north-west Devon
Authors: Jackson P. C.
Published: December 2009

The Dinantian of north-west Devon is represented by a poorly exposed thin pelagic succession. New sedimentological and palaeontological data permit the recognition of five formations: Pilton Shales (partly Devonian), Landkey, Tawstock (three members), Hearson and Rubble Hills. The last four are newly named and defined, and form part of the Codden Hill (Chert) Group.

The two different stratigraphic successions previously proposed are shown to be based on incomplete sequences and erroneous age assessments. Instead, a fairly uniform stratigraphy is recognised. The local variations that do occur can be explained by either tectonic excision of strata (for which there is independent evidence) or basin floor morphology.

Redeposited pelagic carbonates suggest a submarine rise existed nearby through much of the Dinantian. Limestone turbidites of shallow-water debris also point to topographic highs in the region.
Late Devensian and early Flandrian environments at Dishforth Bog, North Yorkshire
Authors: Giles J. R. A.
Published: December 2009

Pollen and molluscan diagrams are presented from one of a group of kettle holes near Dishforth, North Yorkshire. The pollen diagram records the changes in the plant assemblages in and around the kettle hole during the late Devensian and early Flandrian and it is interpreted in terms of changing environmental conditions. The molluscan assemblages are of early Flandrian age and suggest that the kettle hole then contained quiet, shallow eutrophic water. The palaeoenvironments suggested by these data are discussed.
Gyrochorte
burrows from the Scarborough Formation (Middle Jurassic) of the Cleveland Basin, and their sedimentological setting
Authors: Powell J. H.
Published: December 2009

Gyrochorte
burrows are described for the first time from the Scarborough Formation (Middle Jurassic) of Yorkshire. The burrow consists of a low, winding, bilobate ridge with a paired braided structure and median furrow on the upper surface. It is considered to be the feeding trace of an organism whose body was inclined at an angle to the sediment–water interface. The
Gyrochorte
burrows are preserved in sandstones exhibiting current ripples and bidirectional “herringbone” cross-bedding, interpreted to have been deposited under high-energy, shallow water, tidal conditions of a coastal beach or barrier island facies. The absence of bioturbation in the
Gyrochorte
-bearing sandstones is in marked contrast to the burrow-mottling in the underlying sandstones and suggests that the
Gyrochorte
organism was an opportunistic animal ideally suited to exploiting highly mobile substrates.
The stratigraphy of the Ordovician rocks around Cardigan, Wales
Authors: McCann T.
Published: December 2009

Three formations are formally recognised in the Ordovician rocks between Dinas Head and Cardigan (south-west Welsh Basin). In ascending order, these are the Newport (
c.
200m), Ceibwr (
c.
50m) and Poppit (
c.
300m) formations. The informally named Parrog Shales (
c.
150m) underlie the Newport Formation. The succession is dominated by marine mudstones with sandstone-rich intercalations represented by the Newport and Poppit formations. The Newport Formation is in part of Llandeilo age (
Nemagraptus gracilis
Biozone) and the Poppit Formation in part of Caradoc age (
Dicranograptus clingani
Biozone).
A note on the mineralogy of the chilled margin of the Little Whin Sill at Turn Wheel Linn, Weardale, County Durham
Authors: Dunham A. C. , Wilkinson F. C. F.
Published: December 2009

The compositions of fresh olivine (Fa
30
), augite, pigeonite, orthopyroxene and plagioclase have been determined by electron microprobe analysis of the chilled marginal rock at the base of the Little Whin Sill, at Turn Wheel Linn, Weardale, County Durham. Olivine is altered to talc plus carbonates (pistomesite and calcite), plagioclase to kaolinite and K-feldspar. Pyroxene is little altered. The fresh olivine may have been in equilibrium with the magma on intrusion, but at the end of its range of crystallisation.
Developments in industrial mineralogy: II. Archaeological mineralogy
Authors: Dunham A. C.
Published: December 2009

The address explores the common ground between geology and archaeology, with particular reference to the applications of mineralogy and petrology. Building materials are examined first, with examples from Stonehenge, the Orkneys, Durham Cathedral, the Great Wall of China, Beverley and Hull. In each case the geology has played some part in the nature, utility and choice of the materials. The second section examines the composition, textures, raw materials and manufacturing conditions for a number of artefacts: Scandinavian honestones, a variety of coins and other metal objects, clay smoking pipes and Humberware pottery. The methods of the petrologist/geochemist are applied to these materials, leading at the least to an accurate description of the material, and at best offering some suggestions for the origin of the raw materials and the manufacturing conditions.
The characterisation of calcite-filled fractures from the Northern Pennine Orefield
Authors: Fairbairn R. A. , Ferguson J.
Published: December 2009

Calcite-filled minor fractures and thrusts associated with the major joints and structural features on the Alston Block area of the Northern Pennine Orefield are described in terms of their relationship with the major joints and their organic geochemistry. The field relationships observed show that some of these fractures and the thrusts were healed prior to the joint formation, whereas others are coincident with the principal WNW joint set. The light hydrocarbon gases held in fluid inclusions in the calcite infills are distinctive compared with similar gases held in minerals such as fluorite, deposited during the mineralisation of the orefield. Infills normally have between 10,000 and 20,000 vppm/cc methane, whereas fluorite from the orefield rarely contains more than 1,200 vppm/cc. Also, there are high correlations between the gases ethane, propane, I- and N-butane, which are not shown by these gases from fluorite. These and other factors lead to the conclusion that the calcite fracture infills examined were deposited at or about the same time as the joint formation, from a fluid which differed from that responsible for the main mineralisation event.
Fraipontite from Wensleydale, North Yorkshire
Authors: Young B. , Livingstone A. , Thomson N.
Published: December 2009

The rare zinc-rich kaolinite – serpentine group mineral fraipontite has been found in dump material derived from workings on the Virgin Moss Vein in Wensleydale, North Yorkshire. The mineral is interpreted as the product of supergene reaction between sphalerite, and aluminium and silica-rich ground-water derived from shale and chert wall-rocks.
The belemnite faunal changes across the Hauterivian–Barremian boundary in north-east England
Authors: Mitchell S. F.
Published: December 2009

Newly collected material from the Speeton Clay (Lower Cretaceous) indicates that the belemnite
Præoxyteuthis
ex gr.
pugio
enters the succession at the level of a widespread incursion of Boreal-derived
Acroteuthis (Boreioteuthis).
This is slightly earlier than previously recorded. Rare examples of
Præoxyteuthis danfordi
sp. nov. enter below this horizon indicating the existence of an earlier
Præoxyteuthis
fauna. Belemnite preservation indicates levels of non-sequence within the section corresponding to ammonite and belemnite zonal boundaries. The belemnite faunal changes do not coincide with the base of the Barremian as currently defined by ammonites. The new oxyteuthid
Præoxyteuthis danfordi
sp. nov. is described.
Storm, wave and tide-dominated sedimentation in the Dinantian Middle Limestone Group, Northumbrian Basin
Authors: Reynolds A. D.
Published: December 2009

Marine limestones divide the Dinantian Middle Limestone Group in the Northumbrian basin into a number of coarsening and shallowing-upwards siliciclastic sequences that are considered to have been deposited in a deltaic setting. Detailed facies analysis reveals that the delta fronts were dominated by storm and wave processes, and that tidal distributary channels occurred.
Spore-dominated assemblages from the lowermost Reading Beds (Palaeocene) of North Essex
Authors: Jolley D. W.
Published: December 2009

Palynological assemblages recovered from horizons within the late Palaeocene Reading Beds of north Essex contain an unusual Pteridopyte spore-dominated microflora. These assemblages are dominated by
Camerozonosporites heskemensis
(Pflanzl in Murriger & Pflanzl) Krutzsch 1959 and
Leiotriletes maxoides
Krutzsch 1962 and are lacking in significant numbers of angiosperm and gymnosperm pollen. It is suggested that this microflora was derived from a fern-dominated primary colonising community exploiting an unstable floodplain environment. The Pteridopyte-dominated community is contrasted with the angiosperm-dominated communities identified in south Essex, London and the North Sea Basin.
The Mercia Mudstone Group (Trias) of the Cheshire Basin
Authors: Wilson A. A.
Published: December 2009

New stratigraphic names are proposed for four of the clastic formations within the Mercia Mudstone Group. Detailed lithological correlation within the basin and beyond is made on the basis of degree of lamination and rock colour. A wealth of sedimentary structures provides clues to the likely genesis of the clastic deposits and the major beds of halite.
Sedimentology of the late Quaternary barrage tufas in the Wye and Lathkill valleys, north Derbyshire
Authors: Pedley H. M.
Published: December 2009

Related sequences of Holocene fluvial tufa deposits occur in two north Derbyshire valleys. The Lathkill deposits extend, with a break, back into the Devensian and are continuing growth at the present. The Flandrian Wye valley tufas were extinguished historically by pollution and siliciclastic input.

A three-dimensional facies framework has been constructed from subsurface data provided by percussion auger sampling and resistivity surveying. Phytoherm barriers are dominated by mosses and semi-aquatic plants heavily encrusted with isopachous sparry calcite fringe cements and lesser developments of micrite fringe cements. The pools and ponded areas upstream of the barriers are dominated by phytoclastic wackestones and cyanoliths (oncoids).

Palaeoenvironmental reconstruction indicates that both of the successions are part of a formerly extensive barrage tufa system comparable in type with the Plitvice systems of Croatia. It is suggested that the older Lathkill tufas were deposited under warmer, interglacial conditions.
A new specimen of
Protorosaurus
(Reptilia: Diapsida) from the Marl Slate (late Permian) of Britain
Authors: Evans S. E. , King M. S.
Published: December 2009

The reptilian genus
Protorosaurus
is well known from the late Permian Kupferschiefer of Germany, but until now there has been only one British specimen, a partial postcranial skeleton from a railway cutting near Middridge Quarry, Co. Durham. We report here on the discovery of a second specimen at Quarrington Quarry, near Durham. Parts of the cervical and caudal vertebral series are preserved, with fragments of the trunk, pectoral girdle and, more importantly, isolated bones of the skull.
Graptolites from the Manx Group
Authors: Rushton A. W. A.
Published: December 2009

A newly found
in situ
graptolite fauna from the Manx Group on the SE coast of the Isle of Man is prolific but fragmentary; it suggests an Arenig (early Ordovician) age for part of the Lonan Flags Formation. Bolton’s (1899) record of
Dictyonema
–like graptoloids from Cronk Sumark is considered valid. The ages suggested by the graptolites are comparable with those inferred from micropalaeontology, but are not compatible with Simpson’s (1963) stratigraphical succession for the Manx Group.
Silurian graptolite faunas of the Balbriggan Inlier, counties Dublin and Meath, and their evolutionary, stratigraphical and structural significance
Authors: Burns V. , Rickards R. B.
Published: December 2009

The Llandovery, Wenlock and Ludlow graptolites of the Leinster and Bellewstown terranes of the Balbriggan Inlier give a precise indication of their comparative stratigraphies. The earliest Silurian strata proven, north of the Lowther Lodge Fault that separates the Bellewstown (Northern) Terrane from the Leinster (Southern) Terrane, are referable to the
riccartonensis
Biozone (Wenlock). Comparisons are made between the Balbriggan and Skerries formations of the Leinster Terrane, the Silurian of the Bellewstown Terrane, and the Windermere Group (Silurian) of the English Lake District (Cumbria), the Howgill Fells (Cumbria) and parts of Yorkshire.

Twenty graptolite species have been identified in the Bellewstown Terrane enabling unambiguous recognition of mid-Wenlock (
riccartonensis
and
rigidus
biozones) to early Ludlow (
nilssoni
Biozone). The Denhamstown Formation is shown to encompass the
riccartonensis
to
lundgreni
biozones, whilst the Clatterstown Formation and Kennetstown Formation can be referred respectively to the
ludensis
(Wenlock) and
nilssoni
(Ludlow) biozones. The faunas are of palaeobiological interest on several counts, but most strikingly because of the presence of
Monograptus flemingii warreni
subsp. nov. (here described); an evolutionary intermediate between
Monograptus
ex gr.
riccartonensis
and
M.
ex gr.
flexilis;
and the possible occurrence of
Pristiograptus parvus,
a species currently critical in global correlations.
Alate halite in the late Permian Rotten Marl of Tees-side, north-east England
Authors: Smith D. B.
Published: December 2009

Scattered delicate, unusually alate crystals of displacive halite occur in the late Permian Rotten Marl of north-east England. Where they intersect, they locally give rise to complex networks of thin vein-like halite sheets. The alate halite appears to have been formed after compaction of the host sediment was complete or nearly so, but before it became brittle enough to fracture.
Thermal maturation of the Lower Carboniferous strata of the Northumberland Trough and Tweed Basin from conodont colour alteration index (CAI) data
Authors: Armstrong H. A. , Purnell M. A.
Published: December 2009

Conodont colour alteration (CAI) values for the Lower Carboniferous strata of the Northumberland Trough and Tweed Basin, northern England, can be attributed to three causes. On a regional scale, CAI values of 1.5 – 2 in the Solway and Northumberland basins are due to depth of burial. High values in excess of CAI 5 are localised in the thermal aureoles of Permo-Carboniferous intrusions. In southern Northumberland, CAI values for Brigantian strata are higher than those for Tournaisian and Chadian to Asbian strata. It is suggested that this was caused by the onset of hydrothermal circulation and release of hot brines from the lower crust during Late Carboniferous transpression. This heating event was short lived; it occurred during the earliest Stephanian and was coeval with the intrusion of the Whin Sill and the early phases of Pb-Zn mineralisation in the North Pennine Orefield.
Geophysical log signatures in the Eden Shales (Permo-Triassic) of Cumbria and their regional significance
Authors: Holliday D. W.
Published: December 2009

Comparison between the geophysical logs and the core descriptions of four boreholes in the Eden Shales of Cumbria shows fair correspondence between the two, although neither on its own is adequate to characterise fully the rock sequences. A number of basin-wide log markers allow detailed correlation between the boreholes. Regional comparison of geophysical log patterns suggests that evaporite deposition spread from the Southern North Sea Basin into the Vale of Eden at times of relatively high sea level, from late EZ1 times onwards, although sedimentation in the adjacent Carlisle Basin was not similarly affected. Regional uniformity of geophysical log patterns in rocks throughout northern England and adjacent areas, from EZ3 and, more particularly, EZ4 times onwards, reflects decreased basin isolation and the progressive elimination of the topographic expression of structural highs.
Lithostratigraphy of a concealed caldera-related ignimbrite sequence within the Borrowdale Volcanic Group of west Cumbria
Authors: Millward D. , Beddoe-Stephens B. , Williamson I. T. , Young S. R. , Petterson M. G.
Published: December 2009

A sequence of volcaniclastic rocks, more than 1200m thick, is described from beneath Permo-Triassic and Carboniferous rocks in the Sellafield area of west Cumbria. The rocks are locally weakly cleaved and are considered to be part of the Ordovician Borrowdale Volcanic Group which crops out a few kilometres to the east. Seven formations are defined from six of the deep boreholes drilled by UK NIREX Ltd. The rocks are predominantly high-grade welded ignimbrites. Abrupt lateral thickness changes and intraformational collapse mesobreccias characterize the sequence. The ignimbrites range from andesite to high-SiO
2
rhyolite. Individual formations show distinctive vertical zonation profiles. Compositions fall on a common magmatic trend, indicative of a similar fractionation history. There is no overall compositional trend with time through the succession, though the high-SiO
2
rhyolites were probably erupted early in the cycle. Deposition is considered to have been within an actively subsiding basin, probably a caldera complex. This is considered to have had an episodic history, with periods of caldera collapse following eruptions during which an evolving magma chamber was tapped.
Triassic sandy braidplain and aeolian sedimentation in the Sherwood Sandstone Group of the Sellafield area, west Cumbria
Authors: Jones N. S. , Ambrose K.
Published: December 2009

During the Permo-Triassic the Sellafield area formed part of the eastern margin to the East Irish Sea Basin. Basin-margin alluvial fan, shallow marine and coastal mudflat sedimentation created a locally thick Permian succession. Triassic sediments are represented by the Sherwood Sandstone Group, which comprises the St Bees, Calder and Ormskirk sandstone formations. The basal few metres of the St Bees Sandstone are characterized by sheetflood sandstones, interbedded with playa-mudflat deposits. These pass upwards into thick, multistorey fluvial sandbodies, formed on sandy braidplain. Rare aeolian units are interbedded with the channel facies. The top of the St Bees Sandstone is sharply defined and represents the regional abandonment of the fluvial system. The overlying Calder Sandstone Formation is coarser grained and dominated by aeolian sediments, with dune and interdune facies recognized. These sands were blown into the area from the east. Minor episodes of fluvial reworking punctuated aeolian deposition and the top of the Calder Sandstone is represented by a fluvially deposited unit. The lower part of the overlying Ormskirk Sandstone is of aeolian facies and can be distinguished from the Calder Sandstone by its finer grain size. The two formations can also be differentiated using geophysical logs, as aeolian and fluvial sandstones have diagnostic geophysical log characteristics allowing recognition of different sedimentary facies associations.
The petrology and diagenesis of Permo-Triassic rocks of the Sellafield area, Cumbria
Authors: Strong G. E. , Milodowski A. E. , Pearce J. M. , Kemp S. J. , Prior S. V. , Morton A. C.
Published: December 2009

A study of the petrology and diagenesis of the Permo-Triassic rocks of the Sellafield area has been undertaken as part of the Core Characterisation Programme for UK NIREX Ltd. This paper summarizes observations of the petrology and diagenesis from boreholes 1/1A, 2, 3, 7A and 7B of the Brockram, St Bees Evaporites, St Bees Shale and St Bees Sandstone and proposes a series of Diagenetic Episodes (denoted DE1 to DE10) to describe paragenetic relationships inferred from these observations.

As might be expected from closely spaced boreholes, overall paragenetic characteristics are laterally similar for each stratigraphic unit, although the degree of development and preservation of authigenic minerals, cements and porosity characteristics varies between boreholes. However, there are more significant differences in diagenetic characteristics between stratigraphic units. In general, the diagenesis of the Brockram breccias is characterized by precipitation of anhydrite, calcite, ferroan calcite, dolomite, ferroan dolomite, ankerite, hematite, barite, kaolinite and illite; the St Bees Shales and Evaporites by sulphates and dolomite; and the St Bees Sandstone by non-ferroan dolomite, quartz, ferroan and non-ferroan calcite and late illite.

Total porosity in the Brockram, St Bees Evaporites and St Bees Shales is negligible (<1 %), but there is significant porosity (
c.
15–25%) in the St Bees Sandstone, most of which is considered here to be secondary porosity attributed to removal of carbonates by present-day groundwaters, but ultimately due to early preservation of non-compacted fabrics by an inferred early evaporite cement, probably anhydrite, which was subsequently removed during diagenesis.
The post-Triassic structural evolution of north-west England and adjacent parts of the East Irish Sea
Authors: Chadwick R. A. , Kirby G. A. , Baily H. E.
Published: December 2009

Available data suggest that, subsequent to Triassic basin development, syn-depositional normal faulting continued in Jurassic and early Cretaceous times with subsidence of the East Irish Sea and Solway basins relative to the Lake District Block. Cessation of extension in the mid-Cretaceous led to regional subsidence with little distinction between blocks and basins. Palaeogene times heralded a period of regional uplift and erosion, associated with development of the Icelandic Plume and emplacement of the Scottish Tertiary igneous province. Superimposed upon this, Alpine crustal compression produced minor oblique-reversal of the basin-margin faults and weak basin inversion. Depth of burial estimates from well-log data agree with uplift values computed from thermal modelling of apatite fission-track palaeotemperatures. They indicate that post-Cretaceous uplift ranged from less than 1750 m over the Lake District Block, to 2000 m at Sellafield and more than 2200 m over the surrounding basins.
Deformation of the Upper Cretaceous Chalk at Selwicks Bay, Flamborough Head, Yorkshire: its significance in the structural evolution of north-east England and the North Sea Basin
Authors: Starmer I. C.
Published: December 2009

Four deformation phases (D1–4) can be recognized in the Upper Cretaceous Chalk of Selwicks Bay.

D1 ENE–WSW compression formed gentle NNW–SSE buckles in Selwicks Bay, with localized overturned folds and minor thrusts to the south. Regionally, D1 is correlated with Laramide sinistral slip on the Dowsing Fault, inversion of the Sole Pit Basin, and N–S to NNE–SSW folding in the Cleveland Basin. Subsequent D2 extensional fracturing developed during general post-Laramide tension, with a dominant E–W component at one stage.

D3 N–S compression produced gentle E–W folds, later tightened in the south of Selwicks Bay as sinistral E–W strike-slip faults formed in the north: subsequent southward and northward thrusting resulted from NW–SE transpression across the whole area. North of Selwicks Bay, the Bempton Fault Zone underwent E–W folding and N–S thrusting, and the E–W Cleveland Anticline was enhanced, causing some inversion of the Cleveland Basin. The strike-slip faulting is interpreted as a derivative of Alpine dextral slip on the Dowsing Fault, which subsequently caused the NW–SE transpression.

D4 deformation at Selwicks Bay produced N–S normal faults with later dextral shear, followed by northward spreading of faulting in a N–S extension complex. Regionally, this is correlated with E–W tension, caused by North Sea subsidence, becoming modified and eventually dominated by uplift (enhanced inversion) of the Cleveland Basin: this tilted the region south to Selwicks Bay, where hinging produced a classic N–S extension complex.
Bromine content of English Zechstein Cycle 3 chloride salts on Teesside and in the Staithes area of Co. Cleveland, N.E. England
Authors: Smith D. B. , Raup O. B. , Holmes R.
Published: December 2009

We present profiles of the vertical distribution of bromine in cores of the late Permian (Zechstein) Boulby Halite Formation (EZ3 Na) from lower Teesside and from the potash field around Boulby Mine, Staithes, North Yorkshire. The profile for the Teesside core shows that the bromine content of the halite there (and therefore the salinity of the originating brine) lies in the lower part of the range regarded as normal for marine-derived brines throughout deposition of the formation and increases only slightly near the top. The bromine content of the Boulby Halite in the potash field core is generally slightly greater than that in the Teesside core, but, as predicted by conventional theory, increases sharply in the Boulby Potash Member near the top of the formation. Comparison of the two bromine concentration profiles suggests a close correlation. This suggested correlation needs to be tested against other bromine profiles but, if correct, implies (a) that closely sampled bromine profiles are a useful tool in the correlation of salt deposits, and (b) the Boulby Potash is entirely, or almost entirely, younger than the Boulby Halite of Teesside, possibly indicating basin-shrinkage.
Calcite concretions in carbonate rocks of the late Permian Raisby Formation, north-east England
Authors: Lee M. R.
Published: December 2009

Calcite concretions have been discovered recently in metre-thick limestone beds close to the base of the Raisby Formation. They are composed of coarse, inclusion-rich, radiating calcite crystals and pass laterally into thin, impersistent, coarsely crystalline dolostone beds. The concretions are inferred here to have formed by aggrading neomorphism of partially dolomitized aragonite and high magnesian calcite-dominated carbonate sediments during early burial. Concretion calcite was precipitated from a radially advancing solution film in a relatively open diagenetic environment. After concretion calcite had ceased to precipitate, aragonite and high magnesian calcite in carbonate sediments surrounding the concretions continued to dissolve, leaving a porous residue of less soluble fossils, corroded dolomite crystals and non-carbonate grains. During Mesozoic burial, this residue was partially or completely cemented by coarse ferroan dolomite. Following regional uplift during the late Mesozoic/Tertiary, porosity remaining in the residue was occluded by zoned calcite cements, authigenic clays and iron sulphides. The morphological and petrographical similarities between calcite concretions in the Raisby Formation and those in other late Permian carbonates are probably the result of the independent recurrence of a distinctive style of replacive calcite crystal growth.
The age of Acadian cleavage in northern England, UK: K–Ar and TEM analysis of a Silurian metabentonite
Authors: Merriman R. J. , Rex D. C. , Soper N. J. , Peacor D. R.
Published: December 2009

K–Ar and
40
Ar–
39
Ar isotope analysis and transmission electron microscopy were used to study the cleavage developed in a metabentonite during the Acadian tectonometamorphic event in northern England. The Foredale metabentonite, from the Ribblesdale inlier in the Pennines, is one of numerous K-bentonites preserved in the hemipelagic Horton Formation of Lower Ludlow (Gorstian) age. It consists of over 90% phengitic white mica crystallized during deformation and cleavage development under mid-anchizonal metamorphic conditions. Temperatures approaching 250°C combined with strain energy to completely eliminate original smectite interlayers, producing stable crystallites of 1M and 2M mica polytypes. Mica concentrates analysed by the K–Ar method have a weighted mean apparent age of 397 ± 7 Ma;
40
Ar–
39
Ar total fusion analyses have a weighted mean apparent age of 418 ± 3 Ma. The true cleavage-forming event lies within this age range. An inferred geothermal gradient of <25°Ckm
−1
, based on the white mica
b
lattice dimension, suggests that the Foredale metabentonite was buried under at least 10km of overburden, much of it Lower Old Red Sandstone, prior to late Lower Devonian (Emsian) uplift in northern England.
Lithostratigraphy and biostratigraphy of the Hunstanton Formation (Red Chalk, Cretaceous) succession at Speeton, North Yorkshire, England
Authors: Mitchell S. F.
Published: December 2009

The Hunstanton Formation (Red Chalk), as interpreted here, is 24 m thick at Speeton and is divided into five members (Queen Rocks, Speeton Beck, Dulcey Dock, Weather Castle and Red Cliff Hole), each of which is characterized by a distinctive lithology. Above the Red Chalk, in the Ferriby Chalk Formation, a further member is established (Crowe’s Shoot Member) which extends the succession up to the regionally important marker, the First
Inoceramus
Bed. The lithological boundaries between the lowest three members of the Red Chalk are close to important changes in the belemnite assemblages and consequently belemnites, which are abundant, provide the most suitable fossils for placing small sections of Red Chalk within the lithostratigraphical scheme. The distribution of the most important macrofossils is described and used to suggest a correlation of the Red Chalk succession at Speeton with the standard ammonite zones and subzones established in southern England. This demonstrates that Red Chalk deposition began in early Mid-Albian times at Speeton, similar to other sections in north-east England (e.g. South Ferriby and Hunstanton), and the transition to ‘white chalk’ deposition occurred during the earliest Cenomanian. The Albian-Cenomanian boundary is recognized using the carbon isotope signature and compared with various biostratigraphical markers previously used for the Albian-Cenomanian boundary. A comparison of the Red Chalk succession between Speeton, South Ferriby and Hunstanton shows a number of regionally important erosional/flooding surfaces, and these have also been recognized in southern England. Three new species of brachiopod
(Concinnithyris microsubundata
sp. nov.,
Nerthebrochus nosetrapensis
sp. nov. and
Atactosia jeansi
sp. nov.) are described.
Three new early Namurian (E
1c
-E
2a
) marine bands in central and northern England, UK, and their bearing on correlations with the Askrigg Block
Authors: Brandon A. , Riley N. J. , Wilson A. A. , Ellison R. A.
Published: December 2009

Three new marine bands are recognized in the exceptionally thick Lower Namurian succession of the northern part of the Central Pennine Basin, namely the Blacko (late Pendleian), Cravenoceras gressinghamense (early Arnsbergian) and Saleswheel (early Arnsbergian) marine bands.

The stratotype of the Blacko Marine Band (E
1c
2) is within delta-slope siltstone and sandstone of the Surgill Shale Member at the top of the turbiditic Pendle Grit Formation of the Blacko Borehole (near Colne). It comprises marginal marine siltstone and contains the bivalve
Sanguinolites.
The band is correlated with a bivalve-spat phase in the Widmerpool Gulf, and a
Lingula
band lying within the delta-top Grassington Grit Formation on the south-eastern part of the Askrigg Block.

The Cravenoceras gressinghamense Marine Band (E
2a
2α) succeeds the Eumorphoceras ferrimontanum Marine Band (E
2a
2) in the Roeburndale and Sabden Shale formations. At its type locality, along Gressingham Beck, Hornby, near Lancaster, it has yielded the new name-bearing ammonoid. It also contains the lowest appearance of
Selenimyalina variabilis
(Hind) and is characterized by the presence of
Posidonia lamellosa
(de Koninck). In the Widmerpool Gulf, the band is represented by the
Posidonia
phase at two stratigraphical levels.

The Saleswheel Marine Band (E
2a
2β) lies between the C. gressinghamense and Eumorphoceras yatesae (E2
a
3) marine bands. Its type locality is in the lower part of the Sabden Shale Formation at Ribchester, near Blackburn, where it contains
Anthracoceras.
The marine band thickens dramatically towards the Lancaster district into siltstone beds of the Close Hill Siltstone Member containing a
Sanguinolites
-dominated faunal phase. In the Widmerpool Gulf it is represented by a
Lingula
band.

The dramatic thickness and facies changes of early Namurian marine bands across the Central Pennine Basin and on to the Askrigg Block appear to be controlled primarily by proximity to sediment supply, availability of accommodation space, and the duration, rate and amplitude of glacio-eustatic marine flooding events. A regional non-sequence is developed at the base of the Ward’s Stone Sandstone (and equivalents), associated with marked tectonic discordance. This boundary, together with the newly resolved marine band stratigraphy, necessitates lithostratigraphical revision and re-correlation of early Namurian sandstones in the northern part of the Central Pennine Basin and the Askrigg Block.

One new species,
Cravenoceras gressinghamense
sp. nov., is described.
Ecophenotypic variation in the early Silurian rugose coral
Palaeocyclus porpita
Authors: Scrutton Colin T.
Published: December 2009

Palaeocyclus porpita
(Linnaeus) is a highly distinctive and biostratigraphically important early Silurian rugose coral, widespread in north-west Europe and with scattered records in North America. In eastern North America,
Palaeocyclus rotuloides
(Hall) occupies a similar biostratigraphical position, but differs from
P. porpita
in possessing a thin or imperfectly developed epitheca with septal ridges or exposed septal plates and a distinct profile to the undersurface. The calicular surfaces of
P. rotuloides
and
P. porpita
are essentially indistinguishable. The relationship between
P. porpita
and
P. rotuloides
is resolved by material from the Coralliferous Group of Dyfed, south-west Wales. Collections from siliciclastic horizons have
P. porpita
type epitheca, whereas material from thin bioclastic limestone beds has
P. rotuloides
type epitheca.
P. rotuloides
from eastern North America also appears to be associated with thin bioclastic limestones. It is suggested that these two forms were ecomorphs of the same species,
P. porpita
, in which epithecal development was influenced by the character of the substrate. The stratigraphical and palaeoecological distribution of the species is briefly reviewed.
A new specimen of the Carboniferous trigonotarbid arachnid
Maiocercus celticus
(Pocock 1902) from Lancashire, UK
Authors: Dunlop Jason A. , Horrocks Carl A.
Published: December 2009

A new specimen of the fossil arachnid
Maiocercus celticus
(Pocock, 1902) (Arachnida: Trigonotarbida), from the Upper Carboniferous (Westphalian A) Coal Measures of Westhoughton, Lancashire, UK is described. The taxonomy of
Maiocercus celticus
is revised and a new reconstruction is presented.
The
Amoeboceras
faunas of the Upper Calcareous Grit Formation (Jurassic, Upper Oxfordian) of North Yorkshire
Authors: Wright J. K.
Published: December 2009

The Yorkshire Upper Calcareous Grit Formation consists of a sequence of sandstones, impure limestones and argillaceous siltstones ranging from 9 m to 20 m in thickness. Though generally poorly fossiliferous, individual horizons at certain localities can be remarkably fossiliferous, and have yielded some 370 cardioceratid and perisphinctid ammonites. Two localities, Newbridge Quarry near Pickering and Laysthorpe Quarry near Nunnington, are the most prolific source of the cardioceratid ammonite
Amoeboceras
in the Glosense Zone in Britain. Six species are described and figured, of which one,
Amoeboceras newtonense,
is new.
Stratigraphy, microfossils and depositional environments of the lowermost part of the Welton Chalk Formation (late Cenomanian to early Turonian, Cretaceous) in eastern England
Authors: Dodsworth Paul
Published: December 2009

The lowermost part of the Welton Chalk Formation in eastern England conforms to a succession of eight beds, lettered here A to H in ascending order. Beds A and B are equated with the Plenus Marls (
Metoicoceras geslinianum
Zone) of southern England. The Black Band (beds C to E) has yielded palynological assemblages containing the dinoflagellate cysts
Adnatosphaeridium tutulosum
and
Carpodinium obliquicostatum.
Their presence, along with the absence of
Litosphaeridium siphonophorum,
indicates a late Cenomanian age (
Neocardioceras juddii
Zone) for the Black Band. Bed H contains the planktonic foraminiferan
Praeglobotruncana praehelvetica,
an early morphotype of a Turonian marker fossil. The dark, organic-rich marls of beds C to G are probably contiguous with those of the lowermost part of the Herring Formation in the North Sea Basin and together comprise the regional sedimentary record of a much more widespread ‘black shale’ depositional episode. Alternative hypotheses concerning the origin and timing of this episode are reviewed with reference to new microfossil evidence from eastern England. The late Cenomanian to early Turonian dinoflagellate cyst stratigraphy discussed here appears to be compatible with stratigraphies based on planktonic foraminifera, ammonites and geochemistry (δ
13
C) in north-west Europe and the western interior of the USA, possibly indicating connected basin water masses over much of the area during the Cenomanian–Turonian transition.