Northern Pennines Research Articles

Forestry Research in the British Uplands

Most British forests stand in the uplands of Scotland, Northern England, and Wales. ‘Uplands' is a broad rather than precise term for the extensive areas of Britain where land is generally above 200 m and thus includes the Highlands and Southern Uplands of Scotland, the northern Pennines and Yorkshire Moors in England, and the Cambrian Mountains which extend over most of Wales. The forests in these areas comprise about 80 percent of the 2 million hectares of productive forest in Britain.

Cooling and uplift patterns in the Lepontine Alps South Central Switzerland and an age of vertical movement on the Insubric fault line

96 new fission track (FT) apatite and zircon, K/Ar and Rb/Sr biotite and muscovite ages are presented for 19 samples (mainly acid gneisses) from a 40 km traverse through the Lepontine Alps in the Maggia Valley, South Central Switzerland. Plotting measured mineral ages against assumed system closure temperatures yields cooling rates for each sample. The entire profile shows a fairly uniform Late Neogene-Recent mean uplift rate of ∼0.5 mm/a, confirmed by a gradient of FT apatite age with elevation. Cooling from higher temperatures occurred earlier in the south, where uplift rates of ∼2.2 mm/a in the Steep Belt (root zone) indicate >9 km Early Miocene uplift of the northern Pennine block. This uplift started before 23 Ma and is interpreted as resulting from a major phase of backthrusting along the Insubric Line, and as dating the formation of the mylonite belt. Estimated cooling rates constrain the timing of Lepontine Mid-Tertiary metamorphism: 3 schematic models are proposed which also consider published Rb/Sr, K/Ar mica and hornblende and U/Pb monazite ages. Slow cooling, differential initial heating and subsequent cooling of different parts of the Central Alps and post-38 Ma cooling with syntectonic metamorphism at ∼27 Ma are postulated as alternative interpretations of isotopic data and geologic evidence. From extrapolation between K/Ar and Rb/Sr mica ages and apatite FT ages, 240±50° C is proposed as the closure temperature for the retention of fission tracks in zircon.

Peat slides in Teesdale and Weardale, northern pennines, july 1983: Description and failure mechanisms

AbstractPeat landslides that occurred in Upper Teesdale and Weardale in 1983 are described. The slides occurred after thunderstorm rainfall of a very rare intensity and return period. The slope geomorphological features and the vegetation associated with the slide areas are detailed.Baseline geotechnical data are used in a simple retrospective stability analysis, treating the peat slides as shallow translational slips. The analysis demonstrates the probable important role played by open moor drains, natural soil pipes, and prior cracking of the peat (owing to dessication or slow mass movement) in the rapid transfer of water to the failure zone within an impervious sensitive clay beneath the peat.The frequency of peat landslides and the visual persistence of sites is considered briefly in relation to substratum and peat stability within a context of climatic change. It is suggested that there may be a gradation of type from the classic Irish bog‐burst, through failures of intermediate character, to peat slips involving rigid peat blocks. Antecedent conditions and the mechanism of failure need not be similar for mass movements at either end of this spectrum.

Fluvial channel and overbank deposits from the Westphalian of the Durham coalfield, NE England

ABSTRACTThe Westphalian (Upper Carboniferous) Coal Measures of the Durham coalfield in NE England were deposited in lower and upper delta plain environments. Distributary channels crossed the plain and were separated by shallow, interdistributary lakes and bays. Detailed observation of three‐dimensional (3‐D) opencast (surface) mine exposures, in collaboration with subsurface borehole analysis, has revealed the existence of five varieties of channel deposits and two associated overbank facies within the Durham Coal Measures.Major distributary channels were the major avenues of sediment transport across the Coal Measures plain, were variably sinuous, mostly 1–2 km wide and deposited elongate belts of sand mostly up to 5 km wide. Proximal, major crevasse splay channels formed by the breaching of major channel banks during flood events, were straight, sand‐filled and up to 400 m wide. Minor distributary channels formed by the sustained operation of such crevasses, varied from straight to highly sinuous, and deposited ‘shoestring’ sand/mud belts up to a few hundred metres wide. Minor crevasse channels, generally straight and up to 50 m wide, were formed through bank breaching of minor, and in a few cases major, distributaries. Distal feeder channels formed down‐palaeocurrent extensions of minor distributaries which supplied interdistributary minor delta subsystems, were generally straight and up to 200 m wide.Of the two types of channel overbank (levee) deposits recognized, one, comprising thinly interbedded fine‐grained sandstone and siltstone/claystone, is mostly, though not exclusively, associated with major distributary channels. The other, consisting of ‘massive’ siltstones with regularly spaced, thin claystone bands, is uniquely developed at the margins of minor distributary channels.The lower part of the Westphalian A succession in the northern Pennines records a change in the depositional environment upwards from a lower to upper delta plain. Through this transition, major channel deposits show evidence of having evolved from being of dominantly low sinuosity to being more variable in morphology. Channel sedimentation was profoundly influenced by regular, possibly seasonal, variations in flow stage and sediment load.

The progressive illitization of interstratified illite-smectite from Carboniferous sediments of Northern England and its relationship to organic maturity indicators

AbstractInterstratified illite-smectites from Carboniferous sediments from the Alston and Askrigg blocks and the intervening Stainmore trough of the northern Pennines, UK, were examined by XRD. Both blocks are underlain by Caledonian granites. During late Carboniferous times sediments overlying the Alston block were intruded by the Whin Sill. The percentage smectite in illite-smectite (%S in I/S) varies from ∼35% to <5% only homogeneous mudstones give consistent results. In the case of the Askrigg block and Stainmore trough, a good inverse correlation was found between %S in I/S and vitrinite reflectance. Both illitization of illite-smectite and vitrinite reflectance increase towards the centre of the block. This is thought to be related to high heat-flow centred about the granite basement. In the case of the Alston block, there is no direct relationship between clay and vitrinite data, vitrinite reflectance being controlled by the position and thickness of the Whin Sill. Except where close to the contact, the Whin Sill had no apparent effect on %S in I/S. As observed for the Askrigg block, %S in I/S is directly related to the position of the underlying granite. The progressive illitization of illite-smectites of low expandability is very slow when compared to vitrinite alteration in response to rapidly increasing temperature. Consequently, %S in I/S is a potential indicator of thermal maturation in situations where vitrinites, by virtue of their rapid response to increasing temperatures, fail to provide a regional view of heat-flow patterns.

Strontianite from the northern Pennine orefield

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Litho-, Humic- and Pollen Stratigraphy at Quick Moss, Northumberland

This study involves the selection and use of suitable methods for measuring a) the rate of peat growth and b) the degree of humification of peat at Quick Moss, an area of blanket peat in the northern Pennines where the earliest peat is about 8,000 years old. The stratigraphy of the peat section is examined systematically for a) variations in peat growth by adding tablets containing spores of Lycopodium clavatum to peat samples during routine pollen analysis and b) the degree of humification of the peat by chemical extraction and assay of the humic acids present in each sample. Two distinct regions are identified in the peat section and a change in the relationship between growth and humification is found to take place at the boundary between the two. The growth rate and degree of humification of the peat, and consequently the relationship between growth and humification at a specific level in the section, appear to have been principally controlled by the prevailing climate, through its effect on humidity and temperature at the bog surface at the time the peat forming plants were growing. The radiocarbon-dated pollen diagram indicates possible local Mesolithic activity, small scale Bronze Age deforestation and an extensive clearance beginning in pre-Roman times and continuing through and beyond the Roman period. A late expansion of alder, the transition from woodland to bog and a rather prolonged elm decline can be seen on the diagram.

The Westgarth Forster Fault models

Four wooden models to illustrate slips in mineral veins were donated to the Geological Society of London in 1830. Labelled Fo(r)ster models, they are considered to represent two directions of faulting: moderately inclined mineral veins traversed by steep cross veins. Through an ingenious method of construction involving two sheets of wood joined by dovetail slides, one vein direction can be faulted by sliding the two sheets of the other fault one over the other. Two of the models, Nos. II and IV, can be related unequivocally to the ENE productive veins and the cross veins in the Northern Pennine orefield. The other pair of models, Nos. I and III, can be arranged as combinations of the NNW trending Slitt Vein and the ENE Veins. Models I and III would then represent conditions as found in the Weardale area east of the Burtreeford disturbance, whereas Models II and IV refer to the Nenthead district to the west. The models are probably contemporaneous with Thomas Sopwith's early experimentation with models to illustrate faulted strata in the same orefield although his models were not issued for sale until 1841. From the date of accession of the fault models, it is likely that they were made after the issue in 1821 of the second edition of Forster's very practical book: ‘A Treatise on a Section of the Strata from Newcastle upon Tyne to the Mountain of Cross Fell’.

The methane content of some Carboniferous limestones from the northern Pennines and its relationship to mineralisation

SUMMARY Anomalous amounts of methane gas have been detected in Carboniferous limestones collected in an area to the south-east of Rookhope in the Northern Pennines. The significance of this discovery is discussed in relation to the geology of the area. Two origins for the gas are postulated: either it has been generated as a direct result of the mineralisation or it is a consequence of the prolonged existence of a high geothermal gradient in the area. It is argued that, since these two events are likely to be related, the location of methane anomalies might prove a useful technique for mineral exploration in similar geological settings.

Subsidence and sedimentation in the Northumberland Trough

SUMMARY The Northumberland Trough has been recognised as a major east-west structural unit across northern England for almost a hundred years. Lying between the Northern Pennine Block to the south and the Southern Uplands of Scotland ridge to the north, the Trough stretches across Britain from the North Sea to the Solway Firth. Two basins have been described within the Trough – the Northumberland Basin in the east and the Solway Basin in the west. The basins are believed to be separated by a shelf, with shallow basement running northwards and continuing the line of the Pennine ridge across north-east Cumbria. The Bewcastle anticline is regarded as a drape over this basement high. The oldest deposits proved in the basins are Chadian (Lower Carboniferous), with no confirmed record of the lowest Courceyan Stage. A complete sequence of more than 3 km of Dinantian and Silesian sediments is known, ranging up to late Westphalian D. Strong differential subsidence in the Northumberland Basin came to an end in the Namurian, and the Westphalian was laid down under conditions of uniform epeirogenic downwarping that effected the marginal blocks in the same way as the Trough. The Solway Basin had very similar Dinantian deposition, but subsidence was more variable in the Silesian and persisted longer, at least until the late Westphalian. Shallow marine and deltaic sedimentation characterise deposition in both basins, with subsidence and rate of deposition having been approximately equal. Marine transgressions and deltaic regressions were a major feature of deposition and caused the development of well-ordered sedimentary cycles of coalbelt type. Four phases of trough filling can be recognised: 1. Progressive marine transgression. 2. Gradual marine regression. 3. Upper delta plain sedimentation. 4. Emergence, with lacustrine sedimentation.

The distribution of barytocalcite and alstonite in the Northern Pennine Orefield

SUMMARY The rare minerals barytocalcite and alstonite, the dimorphs of barium calcium carbonate, are shown to be of widespread occurrence in the barium-bearing deposits of the outer zone of the Northern Pennine Orefield where they generally accompany witherite. Barytocalcite in particular is present in much greater abundance than hitherto supposed and in several deposits is shown to be the dominant barium mineral. Both minerals are abundant only in deposits within a limestone wall rock and are considered to be the products of reaction between late-stage mineralising fluids and the wall rock.

Studies of the Seasonal Course of Carbon Uptake of Eriophorum Vaginatum in a Moorland Habitat: II. The Seasonal Course of Photosynthesis

(1) The seasonal pattern of photosynthesis of different age-classes of leaves of Eriophorum vaginatum was followed in the northern Pennines between May and October 1979. (2) Photosynthetic rates in two classes of overwintering leaves at the start of the season were 40-50% of the maximum rate observed over the whole season. The younger age-class continued to fix CO2 at appreciable rates until September. (3) By late June 1979, a new season's crop of leaves had developed with photosynthetic rates of 0.29-0-35 mg m-2 s-1; these were more than twice the rates of the overwintering leaves. Their photosynthetic rates declined towards the end of the season partly because of a deterioration in environmental conditions and partly because of leaf senescence. (4) The seasonal pattern of leaf development and photosynthetic capacity is compared with that of other graminoid species growing in similar environments.

Sphagnum -dominated peat bog: a naturally acid ecosystem

Sphagnum -dominated peat bogs are naturally acid and cover perhaps 1 % of the Earth’s land surface. The tem poral and spatial variations of pH in a peat-bog in the northern Pennines are used to illustrate the relative im portance of different sources of acidity. At this site, where the pH of rain in summer was 4.0-4.2, rain and cation exchange of metal cations in the rain for H + in the newly grown Sphagnum were of about equal im portance, though cation exchange probably dom inated on hummocks in summer. Strongly acid ‘events’ are likely to follow heavy rain that follows a dry spell. The effects of interconversion of sulphur- and nitrogen-containing compounds on acidity is obscure.

The Firestone Sill ganister, Namurian, northern England—the A 2 horizon of a podzol or podzolic palaeosol

The Firestone Sill is a sandstone of early Namurian age which outcrops in the northern Pennines. Occasionally the top of this sandstone contains a conspicuous white quartz arenite upto 1.5 m thick. This was formerly worked for refractory purposes and became known as the Firestone Sill ganister. The presence of roots, rootlets, soil horizons and pedogenically produced structures, e.g. cutans associated with the quartz arenite suggest that it represents the A 2 (eluvial) horizon of a podzol or podzolic palaeosol. The main processes operating during pedogenesis were the accumulation and incorporation of organic matter into the surface (A 1) horizon, destruction of sedimentary structures by bioturbation (principally rootlets), and the downward translocation of carbonaceous material, clays and other mineral breakdown products. The latter led to a relative quartz enrichment of a few percent in the A 2 (ganister) horizon and resulted in the development of a B-horizon of accumulation. The presence of occasional feldspars in the A 2-horizon and the rather small amount of quartz enrichment which took place in this zone suggest that pedogenesis was of fairly brief duration.

Particulate dynamics, dissolved and total load, in two small basins, northern Pennines, UK

ABSTRACT Suspended sediment and dissolved load were measured in two upland piedmont gravel-bedded streams for one year. In addition, the input of major cations from precipitation and the cation content of springs within the basins were monitored. The dynamics of the suspended load through a series of storm flows are examined in relation to sediment supply and progressive exhaustion effects. The variation in the grain size of the inorganic fraction of the particulate load during the passage of the floods is detailed and variations in the organic content of the load assessed. Two distinct models of dissolved cation concentration response to stream discharge variations are proposed which reflect differences in basin geology. Finally total load calculations are presented for the year.

Studies in the Vegetational History of the Northern Pennines: III. Variations in the Composition of the Mid-Flandrian Forests

Studies in the Vegetational History of the Northern Pennines: III. Variations in the Composition of the Mid-Flandrian Forests

NEW DATA ON TETRAHEDRITE, TENNANTITE, CHALCOPYRITE AND PYROMORPHITE FROM THE CUMBRIAN AND NORTH YORKSHIRE PENNINES

SUMMARY The occurrence and compositions of some copper ore-minerals are described from the Swaledale orefield and the surrounding region in the north of the Askrigg Block, northern Pennines. Tetrahedrite was found at Hanging Lund Scar in the quartz-chalcopyrite ‘feeder zone’ and tennantite at Fell End Clouds in the adjacent zone. Trace element contents in chalcopyrite are compared with those from the Groverake Mine on the Alston Block. A high cobalt/nickel ratio is found in chalcopyrite throughout, but no tin. A very pure pyromorphite was found at Gunnerside, this is thought to be the first record in the Askrigg orefield.

A HYDROGEOCHEMICAL AND STREAM SEDIMENT SURVEY OF THE ASKRIGG BLOCK IN THE NORTHERN PENNINE OREFIELD

SUMMARY A regional hydrogeochemical reconnaissance survey of the southern part of the northern Pennine orefield (Askrigg Block) was undertaken at a sampling density of 1 per 2km 2 . For comparison a stream sediment survey using a sample density of 1 per 7km 2 was also conducted. The water samples were analysed for Na, K, Ca, Mg, Fe, Mn, Sr, Zn, Cu, Ag, Pb, Cd, Co, and Ni by atomic absorption spectrophotometry. Colourimetric methods were used to determine NO 2 , B, and Si, and Fe, NO 2 and pH were analysed by a specific ion analyser. Li was determined by flame photometry and standard wet chemical methods were employed in the determination of SO 4 , Cl, CO 2 , Fe 2+ and Fe 3+ . The stream sediments were analysed by X-ray fluorescence spectrometry. The analytical results (>10,000) were interpreted using multivariate statistical techniques. Examples of geochemical patterns and anomalies related to geology, pollution and mineralisation are identified. Silica analyses have delineated the Namurian outcrop. Certain Pb, Zn, Cu, V, Na and Cl anomalies are attributed to pollution from agricultural fertilisation and old smelting and/or dressing sites. Zn, F, Pb, Cu, Ni, Co and Ba anomalies are coincident with known mineralisation as well as, as yet, unproven ore deposits.

Studies in the Vegetational History of the Northern Pennines: II. An Atypical Pollen Diagram from Pow Hill, Co. Durham

SUMMARY (1) A Flandrian pollen diagram from Pow Hill, Co. Durham, is presented. Its radiocarbon-dated pollen assemblage zones differ from those of other English sites and more closely resemble those of north-eastern Scottish sites. (2) Diagrams from three neighbouring sites show some of the same features. (3) Forest history at Pow Hill is characterized by a long pioneer phase, dominant pine woods from 7210 yr B.P., and a much delayed and limited expansion of oak and alder. (4) Pine remained a major species locally until the forests were felled in late prehistoric times. (5) Factors which may have affected the local forest history include slow weathering of the local sandstone to produce shallow soils, and the prevalence of cold north-east winds and low stratus cloud in spring and early summer.

An Account of a Small Nineteenth-Century Lead Mining Company on Alston Moor

Abstract Thanks to the efforts of Hunt, Raistrick & Jennings and others, working on the records of the Beaumonts, the London Lead Company and the Greenwich Hospital, the affairs of the large and successful mining companies working on the Northern Pennine Orefield are well known. However little has been written of the numerous small mining enterprises that flourished on Alston Moor in the eighteenth and nineteenth centuries. Because of this, the finding of a bundle of documents concerning the running of a small, and unsuccessful nineteenth-century mine is of considerable interest. Greenends was at one time the residence of the Waltons, who had interest in the local mines and the documents probably owe their survival to the fact that Jacob Walton of Greenends was the agent for the company concerned, the Nentsberry Green Lead Mine Co., from 1839 to 1841. Included in the bundle were rough accounts, bills and letters for the periods 1822-9 and 1839-41, as well as an account book for 1829-39. In the back of the...