North Pennines Research Articles

Significance of wind-driven rain (wind-splash) in the erosion of blanket peat

Wind-splash is a process in which wind and rain combine to cause soil erosion. In upland Britain, the conditions necessary for wind-splash erosion are relatively common and frequently occur in locations where blanket peat is an important land cover. A typical location is Moss Flats (North Pennines, northern England, UK). Wind-splash processes were monitored intensively at this site over 3 months using a circular configuration of mass flux sediment samplers, and meteorological data logged from an on-site automatic weather station. Maximum peat flux rates were measured between south-southwest and west-northwest directions in association with relatively moderate intensity, frontal rainfall, typically 4–6 mm h − 1 . Wind-splash processes operate in any direction due to changeable synoptic weather patterns. Windward peat fluxes were typically 2–13 times greater than those recorded at leeward orientations. Spatial patterns of erosion are reflected in the wider landscape through the development of small-scale, erosional landforms (peat hags), which frequently display preferred orientations within the range of maximum peat flux. It is suggested that wind-splash may be a more important process of peat erosion than hitherto reported in UK upland areas.

Spatial variation in concentrations of dissolved nitrogen species in an upland blanket peat catchment

The concentration of nitrogen (N), particularly as nitrate (NO3-N), in upland streams, lakes and rivers is frequently used as a diagnostic of the vulnerability of upland ecosystems to increased atmospheric nitrogen deposition and N saturation. The N content of running waters, however, is generally assessed on the basis of sampling at a limited number of points in space and time within the catchment under investigation. The current study was conducted at Trout Beck, an 11.5 km2 blanket peat-dominated catchment in the North Pennine uplands of the UK. Results from sampling at 33 sites within this catchment demonstrated that the concentrations of all dissolved N species were highly variable, even over short distances. Statistical relationships between the concentrations of NO3-N and dissolved organic nitrogen (DON) and percentage catchment cover of Calluna/Eriophorum and Eriophorum vegetation were found. However, it was also noted that in catchments containing limestone outcrops, NO3-N concentration was much higher than in catchments where runoff was sourced directly from the blanket peat surface. It is possible that NH4-N and DON leached from the blanket peat are mineralised and nitrified, providing a source for the NO3-N found in the river channels. Overall, the current study suggests that interpretations of N-saturation based on river water chemistry measurements at a single point must be treated cautiously, and that the influence of catchment-scale physical factors, such as vegetation and geology cover on the concentration of dissolved N species in upland river waters should not be ignored.

Direct evidence of fluid mixing in the formation of stratabound Pb–Zn–Ba–F mineralisation in the Alston Block, North Pennine Orefield (England)

The North Pennine Orefield Alston Block has produced approximately 4 Mt Pb, 0.3 Mt Zn, 2.1 Mt fluorite, 1.5 Mt barite, 1 Mt witherite, plus a substantial amount of iron ore and copper ore from predominantly vein-hosted mineralisation in Carboniferous limestones. However, a significant proportion of this production (ca. 20%) came from stratabound deposits. Though much is known about the vein mineralisation, the relationship between the veins and the stratabound mineralisation is not well-understood. New petrographic, isotopic and fluid inclusion data derived from samples of stratabound mineralisation allow us to present a unified model that addresses the genesis of both the vein and stratabound styles of mineralisation. The mineralisation can be considered in terms of three episodes:

Wind erosion of blanket peat during a short period of surface desiccation (North Pennines, Northern England)

AbstractStrong winds are a characteristic feature of UK upland areas. Despite this, understanding of aeolian processes in upland environments of the UK is limited. This paper presents direct measurements and observations of blanket peat erosion by wind action during a two week period of desiccation in the North Pennines, Northern England. A circular configuration of mass flux sediment samplers was used to collect peat eroded by wind action from 16 cardinal compass directions. Meteorological conditions (wind speed, wind direction, precipitation and temperature) were recorded by an automatic weather station set up adjacent to the site. Surface desiccation led to peat crust erosion and dust deflation. During short (≤1 hour) periods of precipitation, wind‐driven rainfall also caused erosion. Typically, dust flux rates were up to two orders of magnitude lower than recorded during periods of sustained wet weather. Measurements demonstrate the hitherto unreported rapid switch in process regime between wind‐driven rainfall and dry blow deflation in blanket peat environments. Dry blow processes of blanket peat erosion may become more important in UK upland areas if climate change promotes more frequent surface desiccation. Copyright © 2006 John Wiley & Sons, Ltd.

Sense of place in Northern England

This paper presents a summary of work undertaken by the authors as a contribution towards the International Centre for the Uplands Sense of Place project. The aims of this action research project are to identify if, and how, elements in the cultural landscape of upland Northern England (focusing on the three LEADER+ areas: Fells and Dales (Cumbria), North Pennines and North Northumberland) might contribute to community sustainability.

06/01143 Effect of rapid quenching on the microstructures and electrochemical performances of Co-free ABS-type hydrogen storage alloys: Zhang, Y. et al. International Journal of Hydrogen Energy, 2005, 30, (10), 1091–1098

Data are presented which evaluate the performance of a pilot-scale treatment system using pelletised hydrous ferric oxide (HFO; a waste stream from coal mine water treatment) as a high surface area sorbent for removing zinc (Zn) from a metal mine water discharge in the North Pennines Orefield, UK. Over a 10-month period the system removed Zn at mean area- and volume-adjusted removal rates of 3.7 and 8.1 g m−3 day−1, respectively, with a mean treatment efficiency of 32% at a low mean residence time of 49 min. There were seasonal effects in Zn removal owing to establishment and dieback of algae in the treatment tank. This led to increased Zn uptake in early summer months followed by slight Zn release upon algae senescence. In addition to these biosorptive processes, the principal sinks for Zn appear to be (1) sorption onto the HFO surface, and (2) precipitation with calcite-dominated secondary minerals. The latter were formed as a product of dissolution of portlandite in the cement binder and calcium recarbonation. Further optimisation of the HFO pelletisation process holds the possibility for providing a low-cost, low footprint treatment option for metal rich mine waters, in addition to a valuable after-use for recovered HFO from coal mine water treatment facilities.

Eroding blanket peat catchments: Global and local implications of upland organic sediment budgets

Globally, peatlands account for circa 50% of terrestrial carbon storage containing as much carbon as is present in the atmosphere. The uplands of the UK have an extensive cover of blanket peat but much of it is actively eroding. This paper presents a detailed organic sediment budget for a blanket peat catchment in the north Pennines and comparative data from a catchment in the southern Pennines. The catchments have total sediment yields (organic and mineral) of 44 and 267 t km − 2 a − 1 and organic sediment yields 31 and 195 t km − 2 a − 1 , respectively. They represent two extremes of a spectrum of eroded peat catchments. It is demonstrated that the lower sediment yields in the north Pennines are associated with extensive natural revegetation of the catchment and consequent reductions in slope-channel linkage. Construction of a carbon budget for the north Pennine catchment demonstrates that particulate carbon losses associated with the fluvial suspended sediment load are the largest single carbon loss from the system. The system is currently close to carbon neutral but much higher carbon losses associated with actively eroding systems such as the south Pennine site would make these systems a major carbon source. The possibility that enhanced summer temperatures and winter storminess will accelerate erosion of upland mires means there is a risk that physical degradation of peatlands could become a significant positive feedback on global warming. Mitigation of these potential global effects will depend on local management informed by a clear understanding of peatland sediment dynamics. The sediment budget data here suggest that in gullied peatlands revegetation of gully floors is an effective control on sediment flux so that techniques such as gully blocking are likely to be effective approaches to erosion control.

Influence of drought‐induced acidification on the mobility of dissolved organic carbon in peat soils

AbstractA strong relationship between dissolved organic carbon (DOC) and sulphate (SO42−) dynamics under drought conditions has been revealed from analysis of a 10‐year time series (1993–2002). Soil solution from a blanket peat at 10 cm depth and stream water were collected at biweekly and weekly intervals, respectively, by the Environmental Change Network at Moor House‐Upper Teesdale National Nature Reserve in the North Pennine uplands of Britain. DOC concentrations in soil solution and stream water were closely coupled, displaying a strong seasonal cycle with lowest concentrations in early spring and highest in late summer/early autumn. Soil solution DOC correlated strongly with seasonal variations in soil temperature at the same depth 4‐weeks prior to sampling. Deviation from this relationship was seen, however, in years with significant water table drawdown (>−25 cm), such that DOC concentrations were up to 60% lower than expected. Periods of drought also resulted in the release of SO42−, because of the oxidation of inorganic/organic sulphur stored in the peat, which was accompanied by a decrease in pH and increase in ionic strength. As both pH and ionic strength are known to control the solubility of DOC, inclusion of a function to account for DOC suppression because of drought‐induced acidification accounted for more of the variability of DOC in soil solution (R2=0.81) than temperature alone (R2=0.58). This statistical model of peat soil solution DOC at 10 cm depth was extended to reproduce 74% of the variation in stream DOC over this period. Analysis of annual budgets showed that the soil was the main source of SO42−during droughts, while atmospheric deposition was the main source in other years. Mass balance calculations also showed that most of the DOC originated from the peat. The DOC flux was also lower in the drought years of 1994 and 1995, reflecting low DOC concentrations in soil and stream water. The analysis presented in this paper suggests that lower concentrations of DOC in both soil and stream waters during drought years can be explained in terms of drought‐induced acidification. As future climate change scenarios suggest an increase in the magnitude and frequency of drought events, these results imply potential for a related increase in DOC suppression by episodic acidification.

Sole searching—wasting our time?

Sole searching—wasting our time?

Properties of Fluorite from the North Pennines England

(2004). Properties of Fluorite from the North Pennines England. Rocks & Minerals: Vol. 79, No. 6, pp. 399-400.

Geological controls on the sulphur content of coal seams in the Northumberland Coalfield, Northeast England

The sulphur content of coal is an important consideration when developing reserves for exploitation, driven by emission limits from power stations becoming more stringent. Variations in the sulphur content of Westphalian A and B coals from the predominantly freshwater Northumberland Coalfield, Northeast England, were studied according to their regional, stratigraphic and in-seam location. The observed variation in sulphur content spatially increases towards the source area away from more marine influenced areas, with increased sulphur content through time linked to changes in the general depositional environment as conditions became more marine-influenced. A model of basinal surface water and groundwater flow driven by post-depositional source area tectonism is thought to have played only a minor role in contributing secondary sulphur to the coal. However, the isotopic composition of coal pyrite shows a similar range in composition to that of pyrite and other sulphides from the North Pennine Orefield along the southern margin of the coalfield, suggesting an additional potential source of secondary sulphur, as sulphur-rich fluids were expelled northwards through the coal measures during early Permian Variscan transpression from the south. The Westphalian A and B are interpreted as third-order depositional sequences, defined by third-order maximum flooding surfaces. Each sequence is made up of several coal-bearing fourth-order parasequences, which tend to be more brackish to marine in character, on either side of the third-order maximum flooding surfaces when base level was relatively high. The lowest sulphur coals are confined to the lower to middle, relative low stand part of the Westphalian A third-order base level curve and the lowest part of the Westphalian B third-order base level curve. This difference is attributed to a more rapid rise of base level in the Westphalian B. The stratigraphic and spatial distribution of coal sulphur has been used as a guide to prediction of reserve identification for surface mining operations.

The Moorlands of England and Wales: An Environmental History 8000 BC to AD 2000. By Ian G. Simmons. Edinburgh: Edinburgh University Press Ltd.; distributed in the United States by Columbia University Press (New York), 2004. ix + 414 pp. Illustrations, maps, notes, select bibliography, glossary, index. Cloth $75.00, paper $27.00

This is a history of the moorlands and the part they have played in English and Welsh history over ten millennia. Ian Simmons combines the perspectives of natural science, archaeology, social history and historical geography, and draws on forty years of exploring and studying the moorlands. Starting with a description of their origins and how they have changed under the impact of human and natural forces, Simmons shows how perceptions of the moors have been influenced by writers, artists and the media (and how they have been inspired by the moors), and how these perceptions have resulted in great changes in attitudes to moorland use and management. The book begins by offering some concise understanding of the physical and natural characteristics of moorlands. It then gives an account of how hunter-gatherers of the Mesolithic period altered their surroundings using fire. It describes how millennia of agricultural production wrought distinctive moorland landscapes and how these in turn were affected and sometimes transformed by industrialisation, afforestation and changes in farming methods.The renewed impetus in the twentieth century for environmental management and conservation brings the story near to the present. The North Pennines, Dartmoor and South Wales are the subject of detailed accounts that reveal the common characteristics of the moorlands as well as their marked contrasts. Beyond the recent crises of overgrazing and the 2001 foot and mouth outbreak, Ian Simmons lays out some possible futures for the moors.

Hydrological controls of surficial mass movements in peat

Peat deposits occur in areas where water logging is common. Large areas of blanket mire occur throughout the temperate and cold regions of the Northern and Southern Hemispheres and are particularly extensive in the UK Uplands. Mass movements of peat, reported usually as peat slides and bog bursts, have been well documented for over 150 years. However, the fundamental controls of this form of shallow instability are still poorly understood. The aim of this paper is to review critically the available evidence linking peat hydrology and slope instability. Then, using data from the North Pennine uplands in Northern England, we examine the importance of rainfall, macroscale drainage conditions and peat hydrological processes in initiating slope instability. Shear failure by loading, buoyancy effects, basal liquefaction and surface or marginal rupturing have all been proposed as potential failure mechanisms. Data from Northern England demonstrate that hydrological processes are fundamental in determining the spatial and temporal occurrence of peat slides. Most instabilities are associated with convective summer thunderstorms, although instances of rapid snowmelt and intense winter rainfall have also triggered these events. All instabilities occur in association with distinct drainage features. Slides are initiated along natural drainage lines or in association with artificial drainage often brought about by mining activity or agricultural practices. At the scale of the soil profile the special hydrological properties of peat, in particular shallow water tables and low soil hydraulic conductivity, offer important clues to failure mechanisms. Pore water pressures are generally low and vary little in the peat profile and throughout the year. It is clear from observations of subsurface flow that significant volumes of runoff reach considerable depths in the soil. Macropores (flow occurring in pores greater than 1 mm in diameter) are important in delivering surface runoff to deeper parts of the profile and in some instances high pipe water pressures may develop. These findings define several important hydrological controls for surficial mass movements in peat but the prospect of predicting the location and timing of such events is still a long way off.

Hydrological controls of surficial mass movements in peat

Peat deposits occur in areas where water logging is common. Large areas of blanket mire occur throughout the temperate and cold regions of the Northern and Southern Hemispheres and are particularly extensive in the UK Uplands. Mass movements of peat, reported usually as peat slides and bog bursts, have been well documented for over 150 years. However, the fundamental controls of this form of shallow instability are still poorly understood. The aim of this paper is to review critically the available evidence linking peat hydrology and slope instability. Then, using data from the North Pennine uplands in Northern England, we examine the importance of rainfall, macroscale drainage conditions and peat hydrological processes in initiating slope instability. Shear failure by loading, buoyancy effects, basal liquefaction and surface or marginal rupturing have all been proposed as potential failure mechanisms. Data from Northern England demonstrate that hydrological processes are fundamental in determining the spatial and temporal occurrence of peat slides. Most instabilities are associated with convective summer thunderstorms , although instances of rapid snowmelt and intense winter rainfall have also triggered these events. All instabilities occur in association with distinct drainage features. Slides are initiated along natural drainage lines or in association with artificial drainage often brought about by mining activity or agricultural practices. At the scale of the soil profile the special hydrological properties of peat, in particular shallow water tables and low soil hydraulic conductivity , offer important clues to failure mechanisms. Pore water pressures are generally low and vary little in the peat profile and throughout the year. It is clear from observations of subsurface flow that significant volumes of runoff reach considerable depths in the soil. Macropores (flow occurring in pores greater than 1 mm in diameter) are important in delivering surface runoff to deeper parts of the profile and in some instances high pipe water pressures may develop. These findings define several important hydrological controls for surficial mass movements in peat but the prospect of predicting the location and timing of such events is still a long way off.

Can climate change explain increases in DOC flux from upland peat catchments?

Long-term increases in DOC concentration in rivers draining areas of upland peat are a ubiquitous phenomenon in the UK. Several hypotheses have been proposed to explain these increases, but one compelling explanation is the observed long-term increase in temperature in UK uplands causing increases in peat decomposition rates, and increasing the depth of oxidation as evaporation increases depth to the water table. The study constructed an empirical model for water table depth and decomposition rate calibrated against observations from the Environmental Change Network monitoring site at Moor House in the North Pennines, UK. The study shows: (i) Depth of the water table has not changed significantly over a 30-year period, reflecting the fact that blanket peat is well buffered against climate change. (ii) Increases in temperature are responsible for a 12% increase in DOC production while an approximate 78% increase in DOC production has been observed. (iii) Overall DOC production is predicted to rise by 6% but observation suggests increases on the scale of 97%. (iv) The model inadequately represents changes in production and supply of DOC during periods of severe drought. The study shows that temperature change alone is insufficient to explain observed increases in DOC production. Alternative explanations for large increases in DOC production could include changes in land management, but an enzymic latch mechanism, i.e. derepression of anaerobic degradation, causing increased decomposition rates in response to severe drought is preferred.

Lead ingots from a shipwreck off Poompuhar, Tamil Nadu, East Coast of India: evidence for overseas trade and their significance

Various types of lead ingots have been reported from a number of shipwrecks from different parts of the world. In 1991 exploration of a wreck off Poompuhar, Tamil Nadu, East Coast of India, at a depth of 19 m yielded a gun, rudder gudgeon, gunpowder boxes and a variety of lead ingots. The most significant ingots are those marked W: Blackett and D with a crown symbol on the obverse and 1791, 1792 and some merchant marks on the reverse. These are similar to Blackett lead ingots found in England, the Netherlands and Sumatra. Pb-isotopic analysis has revealed their source as the North Pennine lead mines of England. Further, the lead used was of high purity ∼93%. Records show that Blackett was a well-known lead-exporting company in England since 1694. The wreck off Poompuhar may be a Toni type cargo ship carrying traded lead ingots of different manufacturers.

Lead ingots from a shipwreck Off Poompuhar, Tamil Nadu, East Coast of India: evidence for overseas trade and their significance

Abstract Various types of lead ingots have been reported from a number of shipwrecks from different parts of the world. In 1991 exploration of a wreck off Poompuhar, Tamil Nadu, East Coast of India, at a depth of 19 m yielded a gun, rudder gudgeon, gunpowder boxes and a variety of lead ingots. The most significant ingots are those marked W: Blackett and D with a crown symbol on the obverse and 1791, 1792 and some merchant marks on the reverse. These are similar to Blackett lead ingots found in England, the Netherlands and Sumatra. Pb-isotopic analysis has revealed their source as the North Pennine lead mines of England. Further, the lead used was of high purity ∼93%. Records show that Blackett was a well-known lead-exporting company in England since 1694. The wreck off Poompuhar may be a Toni type cargo ship carrying traded lead ingots of different manufacturers.

Tracing element sources of hydrothermal mineral deposits: REE and Y distribution and Sr-Nd-Pb isotopes in fluorite from MVT deposits in the Pennine Orefield, England

Fluorite from Mississippi Valley Type (MVT) deposits in the South Pennine Orefield, England, displays significantly different distributions of rare earths and yttrium (REY) compared to fluorite from similar MVT deposits in the North Pennine Orefield. Samples from the South Pennine Orefield display negative Ce and positive Gd and Y anomalies but lack any Eu anomaly, indicating that the REY were mobilized from relatively pure marine sedimentary carbonates. In marked contrast, fluorite from the North Pennine Orefield lacks any Ce and Gd anomalies but shows a pronounced positive Eu anomaly, suggesting that the REY were provided by different source rock(s), that the mineralizing hydrothermal fluid had experienced higher temperatures prior to fluorite precipitation, and that it was derived from deeper crustal levels in the north compared to the south. The isotopic composition of Sr in Blue John fluorite from the South Pennine Orefield suggests that Sr was mobilized from Lower Carboniferous (Tournaisian) limestones, whereas Pb isotopes suggest that in contrast to REY and Sr, Pb was derived from aluminosilicate rocks. Neither Nd nor Sr or Pb isotopes can be used to radiometrically date the formation of Blue John fluorite. All isotope systems studied indicate that the limestone host rock of this fluorite mineralization did not contribute to the trace element budget of the hydrothermal fluid. Our results show that different solutes in a natural water (hydrothermal fluid, groundwater, etc.) may be derived from different sources, and that the study of a small set of elements or isotope ratios may not provide full insight into the genesis or history of a mineralization or a hydrothermal fluid. Our data provide evidence for the uncoupling of Sr, Nd and Pb during fluid-rock interaction and fluid migration, and show that the use of plots such as 87Sr/86Sr vs. eNd. to learn about mixing relationships (as is commonly done in igneous geochemistry) is unreliable when applied to natural waters and their precipitates.

Carbon budget for a British upland peat catchment

This study describes the analysis of fluvial carbon flux from an upland peat catchment in the North Pennines. Dissolved organic carbon (DOC), pH, alkalinity and calcium were measured in weekly samples, with particulate organic carbon (POC) measured from the suspended sediment load from the stream outlet of an 11.4-km 2 catchment. For calendar year 1999, regular monitoring of the catchment was supplemented with detailed quasi-continuous measurements of flow and stream temperature, and DOC for the months September through November. The measurements were used to calculate the annual flux of dissolved CO 2, dissolved inorganic carbon, DOC and POC from the catchment and were combined with CO 2 and CH 4 gaseous exchanges calculated from previously published values and the observations of water table height within the peat. The study catchment represents a net sink of 15.4±11.9 gC/m 2/yr. Carbon flows calculated for the study catchment are combined with values in the literature, using a Monte Carlo method, to estimate the carbon budget for British upland peat. For all British upland peat the calculation suggests a net carbon sink of between 0.15 and 0.29 MtC/yr. This is the first study to include a comprehensive study of the fluvial export of carbon within carbon budgets and shows the size of the peat carbon sink to be smaller than previous estimates, although sensitivity analysis shows that the primary productivity rather than fluvial carbon flux is a more important element in estimating the carbon budget in this regard.

Anatomy of a Pennine peat slide, Northern England

AbstractThis paper describes and analyses the structure and deposits of a large UK peat slide, located at Hart Hope in the North Pennines, northern England. This particular failure is unusual in that it occurred in the winter (February, 1995) and shows excellent preservation of the sedimentary structures and morphology, both at the failure scar and downstream. The slide was triggered by heavy rain and rapid snowmelt along the line of an active peatland stream flush. Detailed mapping of the slide area and downstream deposits demonstrate that the slide was initiated as a blocky mass that degenerated into a debris flow. The slide pattern was complex, with areas of extending and compressive movement. A wave‐like motion may have been set up in the failure. Within the slide site there was relatively little variability in block size (b axis); however, downstream the block sizes decrease rapidly. Stability analysis suggests the area at the head of the scar is most susceptible to failure. A ‘secondary’ slide area is thought to have only been initiated once the main failure had occurred. Estimates of the velocity of the flowing peat mass as it entered the main stream channel indicate a flow velocity of approximately 10 m s−1, which rapidly decreases downstream. A sediment budget for the peat slide estimates the failed peat mass to be 30 800 t. However, sediment delivery to the stream channel was relatively low. About 37% of the failed mass entered the stream channel and, despite moving initially as debris flow, the amount of deposition along the stream course and on the downstream fan is small (only about 1%). The efficiency of fluvial systems in transporting the eroded peat is therefore high. Copyright © 2003 John Wiley & Sons, Ltd.