bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Welton Formation (Chalk Group) at Speeton, NE England: implications for the late Cretaceous evolution of the Market Weighton Structure
Authors: Mitchell Simon F. 
Published: December 2009

SUMMARY
The stratigraphy of the Welton Formation (Chalk Group, Upper Cretaceous) at Speeton, NE England, is described for the first time. The marker horizons of the standard succession on the East Midlands Shelf are clearly recognizable at Speeton and demonstrate that the succession is of comparative thickness to that developed on the East Midlands Shelf. The succession is divided into three: the Flixton, Buckton and Bempton members, which can be traced throughout NE England. Considerations of changes in the rates of sedimentation between the East Midlands Shelf, Market Weighton Structure and Cleveland Basin suggest that the Market Weighton Structure, which had dominated sedimentation styles throughout the Jurassic and Lower Cretaceous, had ceased to be an influence on sedimentation rates during the late Cretaceous.
Early Holocene environments of the River Ure near Ripon, North Yorkshire, UK
Authors: Howard A. J. , Keen D. H. , Mighall T. M. , Field M. H. , Coope G. R. , Griffiths H. I. , Macklin M. G. 
Published: December 2009

SUMMARYA sequence of peat and calcareous organic mud from the floodplain of the River Ure near Ripon has yielded pollen, plant macrofossils, Mollusca, Coleoptera, and Ostracoda which allow the first recorded reconstruction of earliest Holocene valley-floor environments for this area. A conventional radiocarbon date on a bulk sample of peat yielded an age of 9710 ± 60bp. The palaeontological evidence suggests that the sediments accumulated in a shallow, slow moving or stagnant water body, surrounded by marshy, damp, grassland, away from contemporary channel processes, probably of a single thread river system. The climate during deposition of the sediments was no warmer than the present, and possibly slightly colder.
Stratigraphic evolution of provenance characteristics in Westphalian sandstones of the Yorkshire Coalfield
Authors: Hallsworth C. R. , Chisholm J. I. 
Published: December 2009

SUMMARY
A combined study of heavy minerals and palaeocurrents shows that three main fluvial systems transported sediment to the Pennine Basin during Namurian and Westphalian times. The first, which brought a garnet-rich monazitic heavy mineral suite from the north, peaked in the Namurian and diminished through the Langsettian. The second flowed from the west, bringing heavy mineral suites with low garnet, low monazite and variable amounts of chrome spinel. It started in the late Namurian, replaced the first system in the Langsettian, and dominated thereafter until it was itself replaced in the late Duckmantian by the third system. This brought a garnetiferous heavy mineral suite with both monazite and chrome spinel from the E or SE and continued to the top of the preserved sequence, in the late Bolsovian. The first sourceland lay to the north, perhaps between Laurentia and Baltica, and included high grade metasediments or charnockites and granites. The second sourceland lay to the west and included mature, pre-existing clastic sediments of Devonian and possibly Lower Palaeozoic age. Ultramafic rocks such as ophiolites, possibly associated with Lower Palaeozoic ocean closure, were periodically exposed there. The third sourceland lay to the south, probably within the uplifting Variscan orogenic belt. It included low to moderate grade metasediments, high-grade gneisses, granites and ultramafic rocks.
The Eycott Volcanic Group, an Ordovician continental margin andesite suite in the English Lake District
Authors: Millward D. , Marriner G. F. , Beddoe-Stephens B. 
Published: December 2009

SUMMARY

The Eycott Volcanic Group, at the northern margin of the Lower Palaeozoic inlier in the Lake District, is the smaller of two substantial middle Ordovician (Caradoc) subduction-related volcanic successions that stratigraphically separate marine sedimentary successions of the Skiddaw Group and Windermere Supergroup. Tabular lavas and subordinate sills, in a sequence up to 2400 m thick, mainly comprise porphyritic basalt, basaltic andesite, andesite and dacite, and are locally interbedded with thin units of volcaniclastic sandstone and pyroclastic rocks; these are overlain by 800 m of acid andesitic pyroclastic rocks. The distribution and form of the lava/sill fades association are consistent with emplacement as a lava plateau sequence, remarkably similar to the Birker Fell Formation, the lower part of the Borrowdale Volcanic Group in the central Lake District. The Eycott Volcanic Group rocks are geochemically coherent with characteristics transitional between medium-K, continental-margin tholeiitic, and calc-alkaline andesite suites. Rocks within the suite can be linked by fractionation of an assemblage of plagioclase, pyroxene, Fe–Ti oxide and apatite. A prominent compositional gap between about 58 and 65% SiO
2
is attributed to the rapid precipitation and segregation of Fe–Ti oxide. Incompatible element concentrations in the mafic members suggest that magmas were derived possibly from a subcontinental lithosphere source, similar to that of the Borrowdale Volcanic Group. The geochemical differences between these two suites arose through the incorporation of different amounts of the subduction component and different fractionation histories.
Felsites and breccias in the Northern Marginal Zone of the Rum Central Complex: changing views,
c.
1900–2000
Authors: DONALDSON C. H. , TROLL V. R. , EMELEUS C. H. 
Published: December 2009

SUMMARY
As in several other parts of the British Tertiary Igneous Province, breccias and felsite sheets are closely associated on the Isle of Rum. This association has been described and interpreted by several workers over the last 125 years. Opinion has divided into an intrusive origin for both rock types, as explosion breccias and felsite intrusions, versus a sedimentary origin for the breccias and an extrusive origin for the felsite. Evidence is reviewed for both opinions and it is concluded that the latter is substantially correct, as indicated by the presence of sedimentary structures and interbedded tuffs in the breccias and eutaxitic textures in the felsites. The breccias formed by inwards slumping of rocks from the oversteepened walls of a caldera, whereas the felsites formed by eruption of pyroclastic flows which were thick and hot enough to weld. It is inferred that the caldera formed initially and subsided progressively without any accompanying eruptions, and this is attributed to growth of the underlying magma chamber. The breccias accumulated during this stage. There followed a resurgent stage in which caldera collapse occurred in response to repeated ignimbrite eruptions partially emptying the magma chamber. The chamber is inferred to have been chemically and mineralogically zoned.
Constraints on the genesis of the mineralization of the Alston Block, Northern Pennine Orefield, northern England
Authors: Cann J. R. , Banks D. A. 
Published: December 2009

SUMMARY
New evidence from fluid inclusion compositions and simple physical modelling provide important constraints on the genesis of the ores of the Alston Block in northern England. Evidence from fluid inclusions shows that probably at least four, hydrothermal fluids were involved, two of which are formed by evaporation of seawater, in some cases well beyond halite saturation. Some of the high-temperature fluid dissolved evaporites during its evolution. Physical modelling shows that neither compactional dewatering of the adjacent Carboniferous sedimentary basins nor compressional tilting and throughflow within the Northumberland Trough could have contributed significantly to the hydrothermal fluids of the orefield. Most of the high temperature hydrothermal flow must have been generated by penetrative circulation of surface brines to 8 to 10 km depth in the basement, with the upflow focused and accelerated by the high heat production of the Weardale Granite that unconformably underlies the Carboniferous rocks of the Alston Block. The orefield is considered to have formed during the Upper Permian by the following sequence of events. Initially, fluid movement in the basement was prevented by sealing of pre-existing cracks, and temperatures rose at depth. An episode of extension allowed saline water, probably from the Upper Permian Zechstein Sea, to penetrate deep into the basement, reacting with the rocks there, and becoming heated to as much as 200°C. Penetration to 10 km took a few tens of thousands of years. The granite, at 300°C at that depth, up to 100°C hotter than the surrounding basement, acted to focus the flow, and to generate concentric zones of increasing temperature fluid towards the centre. Once the basement had become cooled, the flow slowed, cracks became sealed, and the episode of hydrothermal circulation and ore formation was complete.
Advances in the study of ‘black shales’: source rocks for bricks and hydrocarbons
Authors: Hudson J. D. 
Published: December 2009

SUMMARY
Recent advances in methods and concepts in the study of organic-rich mudrocks are reviewed. Organic biomarkers, especially derivatives of isorenieratene, unambiguously identify anoxia within the photic zone of the water column in several well-known black shales. This demands a re-interpretation of much palaeoecological data in terms of intermittent anoxia, rather than only dysoxia, an endeavour aided by increased understanding of the life strategies of benthic invertebrates. The role of sulphur compounds in diagenesis, both organic-bound and as pyrite, is increasingly recognized. Pyrite studies afford anoxicity indices based on pyrite framboids and sulphur geochemistry. The role of organic sulphur is in stabilizing organic matter during kerogen formation, and in ‘fixing’ biomarker molecules. Recycling of nutrients is probably more important than previously thought in forming epicontinental black shales. Reworking of primary organic matter by heterotrophic organisms, especially bacteria, is indicated by isotopic studies on individual organic molecules. All these factors must be integrated with constraints from stratigraphical relationships and basin evolution. Some of these points are illustrated by reference to work by members of the Oxford Clay Working Group in understanding the palaeo-environment of the organic-rich Peterborough Member of that Jurassic formation, a famous source material for bricks and an analogue for hydrocarbon source-rock studies.
The Snelston Ridge: evidence for a concealed ridge of mineralized Dinantian rocks to the south of the Derbyshire Dome
Authors: Cornwell J. D. , Busby J. P. , Colman T. B. , Norton G. E. , Smith N. J. P. 
Published: December 2009

SUMMARY
Little is known of the southern continuation of the Lower Carboniferous (Dinantian) rocks of the Derbyshire Dome where they lie concealed beneath Triassic rocks at the margin of the Needwood Basin. Evidence from regional Bouguer gravity anomaly surveys pointed to the existence of a ridge of shallow Dinantian rocks, here called the Snelston Ridge, largely concealed by Triassic strata apart from two small inliers. The NNW–SSE trending ridge was proved by a borehole which intersected (Dinantian) Widmerpool Formation rocks at a depth of 61 m. Evidence from a seismic reflection profile indicates that the ridge, at least at Birchwoodpark (Snelston), is probably an asymmetrical, fault-controlled anticline. There is, however, no evidence for any significant changes in the thickness of Dinantian rocks hereabouts. The base metal potential of the Snelston Ridge was investigated using detailed geophysical and geochemical surveys and drilling. A borehole on the top of the mineralized mudmound that forms the Limestone Hill Inlier proved minor replacement galena–sphalerite–baryte mineralization with up to 10% Pb over an intersection of about 11 m. Two boreholes on the flanks of the feature revealed little sign of mineralization, indicating that it is restricted to the exposed dolomitized summit of the mudmound.
Biostratigraphy of Jurassic–Cretaceous boundary strata in the Terschelling Basin, The Netherlands
Authors: Abbink O. A. , Colloman J. H. , Riding J. B. , Williams P. D. B. , Wolfard A. 
Published: December 2009

SUMMARY

The Jurassic–Cretaceous boundary beds in the Scruff Greensand Formation from Dutch sector North Sea wells L06-2 (between 2245.36 m and 2262.76 m) and L06-3 (between 2028.90 m and 2037.80 m) have yielded both ammonite faunas and abundant marine and terrestrial palynomorphs. Ammonite endemism in Europe was intense at the Jurassic–Cretaceous boundary. This means that pan-European correlations of Jurassic–Cretaceous boundary beds based on macrofossils are problematical. The ammonite faunas of wells L06-2 and L06-3 provide the most extensive and complete marine macrofossil record so far across the Volgian–Ryazanian (Jurassic–Cretaceous) boundary in the Spilsby Province and the North Sea Basin. The Primitivus, Preplicomphalus, Lamplughi, Runctoni and Kochi Zones have been identified. In both wells, the occurrences of the dinoflagellate cyst
Gochteodinia virgula
mean that the successions are no older than latest mid-Volgian. The dinoflagellate cyst associations of L06-2 are indicative of the late Volgian/early Ryazanian. The range tops of
Gochteodinia virgula
and
Amphorula expirata
are revised as a result of correlations with the ammonite zonation. Dinoflagellate cyst floras in L06-3 are indicative of the latest Volgian–? earliest Ryazanian. In particular, the co-occurrence of
Batioladinium? gochtii
and
Gochteodinia virgula
at 2030.60 m in well L06-3, together with ammonite data, indicates that this horizon is of latest Volgian (Lamplughi Zone) age. Both wells contain reworked palynomorphs, including recycled older Late Jurassic dinoflagellate cysts. In addition, the palynological assemblages yield relatively diverse sporomorph associations. The sporomorph succession of both wells is used to establish an ammonite-calibrated sporomorph chronostratigraphy. Comparison with other studies suggests that the Jurassic/Cretaceous boundary occurs within the Cherty ‘Freshwater’ Beds of the Purbeck Limestone Group in Dorset, southern England, and within the Serpulite Member of Germany.
The Pennine Anticline, northern England – a continuing enigma?
Authors: Evans D. J. , Walker A. S. D. , Chadwick R. A. 
Published: December 2009

SUMMARY
The westward-verging Pennine Anticline extends along the length of the central Pennines. It is an important Variscan fold of flexuous N–S trend developed on the Variscan Foreland. It defines the eastern margins of the Blackburn–Burnley and South Lancashire coalfields, and is commonly viewed as having been formed by the inversion of an underlying down-east Dinantian syn-depositional fault. Seismic reflection and potential field data provide some evidence on the deep structure of the anticline along much of its length. Modelling of gravity data does not provide unique solutions to basement and deep crustal structure beneath the Pennine Anticline. However, the models are consistent with both a basement/upper crustal density boundary and with variations in the Moho topography. In the southern part of the study area, these gravity data appear to define an important NNW–SSE trending, down-east fault that, when traced north, dies out and diverges from the Pennine Anticline. Where imaged by seismic reflection data, particularly over the Central Lancashire High, the fold is underlain by a high-angle reverse fault at basement level. Unusually in this part of northern England, this fault shows little evidence of a Dinantian extensional precursor, perhaps because its trend lay sub-parallel to the Dinantian extension direction. Although the structure remains enigmatic, it is suggested that the two en echelon anticlines mark folding in the Carboniferous cover rocks, developed above a through-going N–S zone of weakness in the basement comprising structures of varying trends. Under NW–SE directed Variscan compression, these structures
The Millstone Grit of northern England: a response to tectonic evolution of a northern sourceland
Authors: Morton A. C. , Whitham A. G. 
Published: December 2009

SUMMARY
The Carboniferous succession of East Greenland is dominated by sandstones, deposited by a major northward-flowing fluvial system. The succession is divided into two parts by a major unconformity that spans late Visean to early Westphalian A times. This time interval corresponds to the development of the Millstone Grit of the Pennine Basin, which was deposited by a southward-flowing fluvial system. Heavy mineral analysis indicates that there are common elements to the provenance of Late Westphalian A sandstones in East Greenland and the Namurian Millstone Grit. It appears, therefore, that the southward extension of clastic facies into the Pennine Basin during the Namurian occurred when uplift in the Norwegian–Greenland Sea region diverted the northward-flowing fluvial system southwards. Supply of sediment from the northern sourceland diminished when rifting during the Westphalian allowed the northward fluvial system in East Greenland to be re-established.
The Memorial Lychgate at St Mary’s Church, Whitkirk, Leeds
Authors: Mitchell M. 
Published: December 2009

SUMMARY
The Memorial Lychgate of St Mary’s Church at Whitkirk in east Leeds was dedicated in 1949. It is an unusual, perhaps unique, War Memorial that commemorates symbolic features from the Second World War. Two stonework panels on the outside of the walls contain blocks from six important war damaged buildings. The stones can be identified as follows: Permian Magnesian Limestone (Cadeby Formation, Anston Stone) from the Houses of Parliament, London; Upper Jurassic Portland Stone from St Paul’s Cathedral, London; Triassic New Red Sandstone (Sherwood Sandstone Group, Hollington Formation) from Coventry Cathedral; Middle Jurassic Ketton Stone from St Martin-le-Grand in York (used for 1920–1930s restoration work); Carboniferous Millstone Grit (Lower Follifoot Grit) from Leeds Town Hall; and Carboniferous Coal Measures (Elland Flags, Harehills Stone) from the Leeds Philosophical Hall and Museum. All these stones played an important part in the history of British building stones, and it is remarkable to find examples of them all at one locality. Their source is discussed.
Early Palaeozoic magmatism in the English Lake District
Authors: Millward D. 
Published: December 2009

SUMMARY
The Lower Palaeozoic rocks of the Lake District record the rifting of the microcontinental terrane of Avalonia from Gondwana early in the Ordovician, its drift northwards across the Iapetus Ocean and collision with Laurentia and Baltica in the Silurian, and its Acadian deformation in Early Devonian times. Three discrete episodes of magmatism occurred during these events. In late Ordovician (Caradoc) times large volumes of magma were generated in response to subduction of Iapetus oceanic crust beneath Avalonia. Large-scale eruptions formed the basalt–andesite–rhyolite volcanic fields that are now preserved as the Eycott and Borrowdale volcanic groups. Large bodies of mainly granitic magma were emplaced beneath the Borrowdale Volcanic Group as part of the largely Ordovician Lake District batholith; these include, for example, the Eskdale and Ennerdale intrusions. Less than 10 Ma later, a brief episode of silicic volcanism is recorded within the marine sedimentary strata of the lowest part of the overlying Windermere Supergroup. A period of about 40 million years of apparent quiescence then ensued before further granitic masses, the Shap and Skiddaw plutons were emplaced around the margins of the batholith in Early Devonian times. All of these magmatic episodes were accompanied by minor intrusions. The Eycott and Borrowdale volcanic groups are rare examples in the geological record of the products of subaerial volcanism. Preservation is entirely due to subsidence keeping pace with the emplacement of new material. Subsidence resulted both from extensional tectonic processes and, locally, during the movement
Allochthonous and indigenous palynomorphs from the Devensian of the Warham Borehole, Stiffkey, north Norfolk, England; evidence for sediment provenance
Authors: Riding J. B. , Rose J. , Booth S. J. 
Published: December 2009

SUMMARY
Late Devensian glaciolacustrine sediments proved by the Warham Borehole, near Stiffkey, north Norfolk, have yielded abundant and diverse recycled palynomorphs of Carboniferous, Permian, Triassic, Jurassic, Early Cretaceous and Palaeogene age. Indigenous Quaternary palynomorphs are a relatively minor component of the palynofloras; Carboniferous and Jurassic palynomorphs are the most commonly occurring forms. Middle Jurassic spores and pollen and Toarcian (Lower Jurassic) and Kimmeridgian (Upper Jurassic) dinoflagellate cysts are prominent, and the latter may indicate derivation from particularly resistant Toarcian and Kimmeridgian lithologies. Surprisingly, few grains were derived from the Chalk Group, which crops out locally. The recycled palynomorphs are interpreted as having been derived from local glacial deposits and then incorporated into the glaciolacustrine sediments of proglacial Lake Stiffkey, at the margin of the Late Devensian ice sheet. The lowest sample studied was the most productive palynologically. It was probably derived from nearby Lowestoft Till, an interpretation that agrees with the sedimentological evidence. The allochthonous palynomorphs from samples collected higher in the glaciolacustrine succession were probably derived from glaciogenic sediments deposited at the margin of the Late Devensian ice sheet. Based on the palynofloras, the Late Devensian ice flowed south from Scotland across the northern Pennines and NE England, down the western flank of the North Sea Basin to north Norfolk. The terrestrial nature of the indigenous Quaternary palynomorphs recovered is consistent with an ice-marginal and glaciolacustrine depositional setting.
Late Visean and Early Namurian trilobites from the northern and eastern margins of the Derbyshire Dome
Authors: Tilsley J. W. , Owens R. M. 
Published: December 2009

SUMMARY

Strata of late Visean (P
1c
and P
2
) and early Namurian (E
l
and E
2
) age that crop out on the northern and eastern flanks of the Derbyshire Dome have yielded trilobites from several horizons in the Monsal Dale Limestones Formation (dark lithofacies), the Eyam Limestones Formation, the Longstone Mudstone Formation and the lower part of the Edale Shale Group. Certain levels are crowded with disarticulated exoskeletal parts, accompanied by some articulated specimens.
Paladin
is the most widespread genus in these formations, both geographically and stratigraphically, with
Cummingella, Baliothyreus
gen. nov. and
Eocyphinium
having more limited distributions. The dark lithofacies at the top of the Monsal Dale Limestones Formation is established as the type lithology for
Paladin bakewellensis
Osmólska,
Eocyphinium seminiferum
(Phillips) and for Martin’s ‘
Entomolithus Onicites
(
Derbiensis
)’, now referred to
Paladin.
In this paper,
Paladin derbiensis
(Phillips),
P. bakewellensis
Osmólska,
P. eakringensis
Osmólska,
Baliothyreus becki
gen. et sp. nov. and
B. fissisolanum
gen. et sp. nov. are described. The
Paladin
species contrast with those present in coeval strata in the Askrigg Block and farther north, in north and south Wales, and in the Bristol district; they appear to be restricted to Derbyshire and the adjacent East Midlands.
Baliothyreus
has not been found outside Derbyshire.