Northern Pennines Research Articles

Provenance response to evolving palaeogeography recorded by Carboniferous sandstones in the northern Pennine Basin, UK

On the basis of a combination of heavy mineral data, provenance-sensitive heavy mineral indices, garnet major element chemistry, rutile trace element chemistry and zircon U–Pb geochronology, six major changes in sandstone provenance during Carboniferous deposition in the northern Pennine Basin, UK, have been recognised. These changes are a manifestation of both tectonic and climatic factors. The earliest Tournaisian sediment was supplied from the local Southern Uplands High, but the increasingly humid climate led to the establishment of the Pennine River system, which introduced northerly-derived sediment from farther afield in the mid Tournaisian. This system was operative until the mid Bolsovian, but shows stratigraphic variations due to changes in input from different parts of the Pennine River hinterland (East Greenland, northern Scotland, western Norway). These variations are believed to be at least partly related to tectonism, since the maximum supply from high-grade metamorphic sources in East Greenland in the Namurian was concurrent with a tectonically-driven change in drainage direction in this part of the northern sourcelands. In addition, at the base of the Visean, there was a temporary influx of mature sediment coincident with a climatically-driven regression and, at the base of the Duckmantian, sediment was briefly introduced from the west as a far-field manifestation of Alleghanian tectonism. Finally, continued uplift of the Variscan mountain belt to the south of the UK led to establishment of northward-directed transport systems that reached the northern Pennine Basin in the mid-Bolsovian, leading totermination of supply from the Pennine River.

Amor Loci: Auden in Rookhope

I present a conspectus of the imaginative geography of the English poet WH Auden. This imaginative geography is avowedly the product of a rootless, cosmopolitan which extols domestic virtues against the backcloth of an originary poetic homeland in Rookhope in the Northern Pennines of England. Auden’s poetry addresses eternal questions about the conditions under which communities thrive or decline, what dividends they bestow upon their members, the costs and benefits of choosing to cultivate local knowledge and attachments and how communities coexist at different scales. Auden’s topopoetics reflects his search for affective bonds in a life marked otherwise by placelessness. It is a quest for a sense of place in the absence of insideness – in this respect it affects more widespread concerns of how to belong to place in an age of hyper-globalisation. Although the landscape of the Northern Pennines held a profound aesthetic attraction for Auden, it was the numinous experience of his youth in Rookhope that allowed him to attach his poetic and personal biography to the place and ascribe its meaning. This amounted to a kind of elective belonging, albeit stripped of any sociological connotation or political commitment.

Discussion on: Supergene sulphuric acid speleogenesis and the origin of hypogene caves: Evidence from the Northern Pennines, UK in Earth Surface Processes and Landforms, 46, 455–464 (2021)

Discussion on: Supergene sulphuric acid speleogenesis and the origin of hypogene caves: Evidence from the Northern Pennines, UK in <i>Earth Surface Processes and Landforms</i>, 46, 455–464 (2021)

Reply to Discussion on: Supergene sulphuric acid speleogenesis and the origin of hypogene caves: Evidence from the Northern Pennines, UK in Earth Surface Processes and Landforms, 46, 455–464 (2021)

Reply to Discussion on: Supergene sulphuric acid speleogenesis and the origin of hypogene caves: Evidence from the Northern Pennines, UK in <i>Earth Surface Processes and Landforms</i>, 46, 455–464 (2021)

‘Block and basin’ style rift basins: sedimentological insights from the Mississippian Fell Sandstone Formation

The block and basin tectonostratigraphic framework for the northern Pennine (rift) Basin, within which buoyant granite intrusions core intra-basin fault-bounded blocks, has long held traction. However, many of the elements of this framework are rooted in primitive tectonic models and, perhaps unsurprisingly, corresponding depositional models often reflect this. Using sedimentological and sedimentary provenance approaches, the synrift (Mississippian) fluvio-deltaic Fell Sandstone Formation and age-equivalent strata within the northern Pennine Basin are examined. Highlighted divergences from classically depicted models relate to occurrences of pre-Carboniferous basement domes or monoclines, which are unbounded by major vertically displacing (&gt;100 m) fault systems. Such structures in the northern Pennine Basin are all granite-cored and their origins are associated with their buoyancy and flexural isostatic processes. One such basement dome, the Cheviot Block, confined and deflected the Fell Sandstone fluvio-deltaic system from the west, causing locally elevated net sand content and variations in the dominant palaeodrainage direction. Central parts of the Alston Block, which forms a regional monocline along an east–west axis, were comparatively uplifted because of flexural isostatic responses to granite intrusions. The findings presented are at variance not only with classically depicted depositional models for the region, but also with more general depictions of dominantly normal fault-driven rift basin systems. Supplementary material: Tables of data locations with derivation, trace element data and major element (oxide) data are available at https://doi.org/10.6084/m9.figshare.c.5733257

Supergene sulphuric acid speleogenesis and the origin of hypogene caves: evidence from the Northern Pennines, UK

AbstractThe maze caves of the Northern Pennines are rectilinear joint‐controlled networks of predominantly tall vertical rifts developed on one level towards the top of a ~20 m thick limestone bed; they were all intersected by underground mines and have no relationship to the present landscape. Passage walls commonly have large, non‐directional scallops; speleothems are uncommon. The caves were previously identified as hypogene in origin, i.e. formed by groundwater ascending from depth, but reassessment of their origin using published data shows that they lack diagnostic hypogene features (rising wall channels, ceiling channels, ceiling cupolas and dome‐pits), and the low permeability strata above and below the limestone bed greatly restrict vertical groundwater flow through the caves. Instead the maze caves were dissolved by the sulphuric acid released by oxidation of iron sulphides (and perhaps chalcopyrite) in the mineralized veins adjacent to all these caves; passage sizes decrease away from the veins and gypsum encrusts the walls of one cave. The maze caves were not formed by vertical groundwater flow, and dissolution was focussed in a relatively small area of limestone beneath an impermeable confining layer. The caves began to form when river incision due to the probably Late Cenozoic uplift of northern England exposed the iron sulphides to weathering and oxidation.The process that formed the maze caves is here termed supergene sulphuric acid speleogenesis, because generation of the acidity was due to near‐surface supergene sulphide oxidation, and differentiated from hypogene sulphuric acid speleogenesis, where the source is at depth beneath the cave.To clarify usage of the term hypogene, it should be restricted to Palmer's geochemical definition (Speleogenesis: Evolution of Karst Aquifers, eds Klimchouk et al., National Speleological Society: Huntsville, AL, 2000; 77–90): dissolution by a deep‐seated source of acidity. Caves dissolved by ascending groundwater containing carbonic acid with a near‐surface origin, e.g. on the rising limb of a phreatic loop, are better identified as epigene. © 2020 John Wiley &amp; Sons Ltd

The influence of low‐density granite bodies on extensional basins

The Carboniferous northern Pennine Basin remains the type locality for the ‘block and basin’ tectonic framework model. It has been widely believed that during periods of tectonic extension, large low‐density bodies within the basement permit buoyant blocks to resist isostatic subsidence. However, lithosphere‐scale structural and geodynamic modelling experiments dispute this; suggesting instead that the formation of intra‐basinal highs occurs prior to lithospheric extension. In northern UK, this tectonic framework is controlled by a combination of tectonic stress, isostasy and the buoyancy forces of low‐density granite, lithospheric flexure and, importantly, the inherited structural framework. It is hoped that further study can lead to a greater appreciation of the interplay of structural and geodynamic process that control the ‘block and basin’ framework.

Dynamic ice stream retreat in the central sector of the last British-Irish Ice Sheet

During the Last Glacial Maximum (LGM), ice streams of the last British-Irish Ice Sheet (BIIS) controlled ice discharge from various dispersal centres. Deglaciation was characterised by shifts in ice-divide location and changes in internal ice-sheet dynamics, resulting in substantial flow switches and significant ice-stream reconfiguration, and hence modification of their landform signatures. We present new geomorphological mapping and 11 10Be cosmogenic nuclide ages from Northern England (Stainmore Gap, Eden Valley and Vale of York), that constrain regional dynamic ice-stream retreat following the LGM. We identify complex decoupling of competing ice lobes, characterised by early retreat of the North Sea Lobe and a minor re-advance of Stainmore ice prior to ∼20 ka. This was followed by rapid recession of the central Stainmore Gap, which was ice-free by 19.8 ± 0.7 to 18.0 ± 0.5 ka, contemporaneous with the recession of the Tyne Gap Ice Stream. In the southern Vale of Eden, Crossby Ravensworth Fell became exposed between 19.2 and 20.3 ka. The northwards ice-flow reversal in the Vale of Eden was associated with the development of ice domes across the northern Pennines, Howgill Fells and the Lake District. This shift in dispersal centres and ice divide migration likely triggered the rapid collapse of eastward ice stream corridors. The central sector of the BIIS rapidly collapsed back up into upland dispersal centres between 20 and 17.5 ka. This work highlights the role internal factors, such as topography, in driving ice-divide migration and flow switches during externally and climatically forced ice-sheet thinning.

The Môn–Deemster–Ribblesdale fold–thrust belt, central UK: a concealed Variscan inversion belt located on weak Caledonian crust

Abstract The Ribblesdale fold belt, representing the Variscan inversion of the Bowland Basin, is a well-known geological feature of northern England. It represents a crustal strain discontinuity between the granite-underpinned basement highs of the northern Pennines and Lake District in the north, and the Central Lancashire High/southern Pennines, in the south. Recent seismic interpretation and mapping have demonstrated that the Ribblesdale fold belt continues offshore towards Anglesey via the Deemster Platform, beneath the Permo-Triassic sedimentary cover of the southern part of the East Irish Sea Basin. The Môn–Deemster fold–thrust belt (FTB) affects strata of Mississippian to late Pennsylvanian age. Variscan thrusts extend down into the pre-Carboniferous basement but apparently terminate at a low-angle detachment deeper in the crust, here correlated with the strongly sheared Penmynydd Zone exposed in the adjacent onshore. Up to 15% shortening is observed on seismic sections across the FTB offshore, but is greater in the strongly inverted onshore segment. Pre-Carboniferous thrusting post-dates formation of the Penmynydd Zone, and is probably of Acadian age, when basement structures such as the southward-vergent Carmel Head Thrust formed. Extensional reactivation of the Acadian structures in early Mississippian time defined the northern edge of the offshore Bowland Basin. The relatively late brittle structures of the Menai Strait fault system locally exhume the Penmynydd Zone and define the southern edge of the basin. The longer seismic records from the offshore provide insights to the tectonic evolution of the more poorly imaged FTB onshore.

Regional variations in fluid formation and metal sources in MVT mineralization in the Pennine Orefield, UK: Implications from rare earth element and yttrium distribution, Sr-Nd isotopes and fluid inclusion compositions of hydrothermal vein fluorites

The Pennine Orefield is one of the most important ore fields for Pb-Zn-Ba-F mineralization in Great Britain. It is subdivided into the Northern Pennine Orefield (NPO), consisting of the Alston and Askrigg Blocks, and the Southern Pennine Orefield (SPO). The Alston Block is underlain by the early Devonian Weardale Granite and the Askrigg Block by the coeval Wensleydale Granite. The potential relationship between the batholiths and the mineralization is a matter of debate. We here studied the rare earth elements and Y (REY) geochemistry, Sr-Nd isotopes and fluid inclusion (FI) compositions of fluorites from the two structural blocks in the NPO and found that the fluorite mineralization in these blocks differ substantially. The REY in Askrigg fluorites show features that are characteristic for leaching of adjacent Lower Carboniferous limestones. In contrast, Alston fluorites have significantly higher REY concentrations, lack REYSN limestone signatures and show a decoupling of redox-sensitive Eu from its trivalent REY ‘neighbours’. Neodymium isotopes indicate a similar crustal source of REY in both blocks, but higher REY concentrations and lower Y/Ho ratios suggest Lower Carboniferous shales as potential REY source in the Alston Block. The fluids that precipitated the Alston fluorites experienced temperatures > 250 °C prior to mineral formation, as evidenced by Eu geothermometry. Fluorite formation, however, occurred at much lower temperatures, as suggested by homogenization temperatures in FI, that fall within ranges of 105–159 °C in Alston and 99–160 °C in Askrigg fluorites. Mineralization of the Mississippi-Valley Type usually lack association with igneous activity. We show that some of the fluids responsible for the NPO mineralization were influenced by magmatic sources. The REY systematics in Alston fluorites may be linked to an interaction of the Permian-age Whin Sill dolerite with the basement granite, which heated fluids and focussed fluid flow into the overlying sedimentary rocks. In the Askrigg Block, where such a dolerite intrusion was not described, fluorites lack any positive EuSN anomalies, indicating that these fluids had never been subjected to temperatures exceeding 200–250 °C.

Emplacement of oil in the Devonian Weardale Granite of northern England

Oil residues occur as solid bitumen in mineralized zones within the Devonian Weardale Granite of the northern Pennines, northern England. Comparable residues are present in the overlying Mississippian rocks and were probably derived from a Carboniferous source, i.e. during later mineralization of the granite. The bitumen was already solidified during fluorite mineralization, which does not contain oil inclusions. The residues do not show the high thermal maturity of organic matter in the region altered by the earliest Permian Whin Sill. Like the sulphide-fluorite mineralization, oil emplacement post-dated intrusion of the sill. Pyrite associated with the oil residues is enriched in trace elements including lead, silver, gold, selenium and tellurium, which suggests that mineralizing fluids at least shared pathways with migrating hydrocarbons and possibly also suggests undiscovered valuable metal resources.

Glacial geomorphology of Teesdale, northern Pennines, England: Implications for upland styles of ice stream operation and deglaciation in the British-Irish Ice Sheet

The glacial geomorphology of Teesdale and the North Pennines uplands is analysed in order to decipher: a) the operation of easterly flowing palaeo-ice streams in the British-Irish Ice Sheet; and b) the style of regional deglaciation. Six landform categories are: i) bedrock controlled features, including glacitectonic bedrock megablocks or ‘rubble moraine’; ii) discrete mounds and hills, often of unknown composition, interpreted as weakly streamlined moraines and potential ‘rubble moraine’; iii) non-streamlined drift mounds and ridges, representing lateral, frontal and inter-ice stream/interlobate moraines; iv) streamlined landforms, including drumlins of various elongation ratios and bedrock controlled lineations; v) glacifluvial outwash and depositional ridges; and vi) relict channels and valleys, related to glacial meltwater incision or meltwater re-occupation of preglacial fluvial features. Multiple tills in valley-floor drumlin exposures indicate that the subglacial bedform record is a blend of flow directions typical of areas of discontinuous till cover and extensive bedrock erosional landforms. Arcuate assemblages of partially streamlined drift mounds are likely to be glacially overridden latero-frontal moraines related to phases of “average glacial conditions” (palimpsests). Deglacial oscillations of a glacier lobe in mid-Teesdale are marked by five inset assemblages of moraines and associated drift and meltwater channels, named the Glacial Lake Eggleshope, Mill Hill, Gueswick, Hayberries and Lonton stages. The Lonton stage moraines are thought to be coeval with bedrock-cored moraines in the central Stainmore Gap and likely record the temporary development of cold-based or polythermal ice conditions around the margins of a plateau-based icefield during the Scottish Readvance.

The Palaeogene Armathwaite–Cleveland Dyke in upper Teesdale, northern England: magnetic characteristics and relationship to mineralization

A magnetometer survey, conducted with the initial aim of delineating the extent of a magnetite-rich orebody within the Teesdale Fault in the Harwood Valley of Upper Teesdale, unexpectedly revealed a Palaeogene remanent magnetization. This is interpreted as reflecting the presence at depth of a hitherto unrecorded section of the Armathwaite–Cleveland Dyke, a member of the Palaeogene Mull Swarm of intrusions. The dyke has now been continuously mapped magnetically from the easternmost outcrop of its Armathwaite section in the South Tyne Valley, near Garrigill, to the westernmost outcrop of the Cleveland section in Ettersgill, Teesdale, where it follows the Teesdale Fault and undergoes a small dextral en-échelon offset. We retain the originally proposed mechanism for the formation of the orebody, by the interaction between Northern Pennine mineralizing fluids and the still hot, recently intruded Permo-Carboniferous Whin Sill and its contact rocks. We find no evidence of a wider distribution of ore, or of Permian magnetization. We conclude that the orebody was emplaced along the Teesdale fault and that its magnetic signature was thermally re-set during the Palaeogene intrusion.

Westgarth Forster’s Strata – a reappraisal of a geological pioneer

In 1809, Westgarth Forster, an agent in the Northern Pennine lead mines, published his only book. Entitled ‘A Treatise on a Section of the Strata…etc.’, it is more usually known simply as his ‘Section of Strata’. Although some contemporaries doubted its originality, the reputation of this work has grown since its publication and Forster is now widely regarded as one of the pioneers of northern England geology. This paper gives an overview of Forster’s life and unsuccessful career before closely examining the text of his work. It shows how most of Forster’s text was copied without acknowledgement from earlier authors and was not drawn from observations made in the Northern Pennine Orefield. Reference is made to earlier sections of strata from mines in the north of England, and Forster’s ‘Strata’ is shown to be drawn mainly from these. Westgarth Forster should not be seen as a pioneer of the geology of northern England, but as an author who pieced together his book very largely from the work of others.

Long-term trends in rain and cloud chemistry in a region of complex topography

Rain and cloud water from a high-elevation site and an adjacent lower-level site in the northern Pennines of England were sampled and analysed between 1994 and 2008. The comparison of wet deposition and rainfall depth at the high and low-level sites has been used to estimate the additional deposition of pollutants arising from ‘seeder–feeder’ enhancement by washout of the orographic cap cloud that forms over the high-level site. The derived ‘orographic scavenging ratio’ for different ions is used to map the orographic enhancement of wet deposition across the U.K. The ratio of ion concentrations in cloud and in rain at the high-level site is also important for estimating the input of pollutants through the direct capture of cloud water droplets at high elevation sites.Long-term trends in ion concentrations in cloud and rain showed significant downward trends in non-sea sulphate, and a weaker downward trend in nitrate, but no trend in other ions. There was also no trend in the orographic scavenging ratios, implying that the methods used to estimate orographic enhancement across the U.K. are robust over time.

A 3300-year atmospheric metal contamination record from Raeburn Flow raised bog, south west Scotland

There is now a plethora of records of atmospheric metal deposition across Europe based on total concentrations and calculated enrichment factors. However, to place such records into an archaeological context and to identify anthropogenic contamination signals more accurately, it is important to separate the signals derived from anthropogenic activities from those of a natural origin. This study presents a new 3300-year record from a bog in the vicinity of Hadrian's Wall and the Northern Pennine orefield in order to generate a new atmospheric metal deposition record for this archaeologically important part of the British Isles. For this purpose multi element geochemistry was undertaken to apportion the contribution of trace metals (lead, zinc, copper, arsenic and mercury) and sulphur as a result of mining/metallurgy and/or geogenic processes. To extract the different contributions through time we used total concentrations and enrichment factors (EF), and applied principal component analysis (PCA) to the dataset. The PCA extracted 7 components: at least two components are necessary to elucidate the trace metal distribution. Zinc, arsenic and lead are mostly related to atmospheric pollution, while mercury and copper appear to be more closely associated with organic matter. Based on these results four phases of lead contamination have been identified that date to: I, c. 2350–1500 cal BP; II, c. 1050–700 cal BP; III, c. 500–350 cal BP and IV, 250 cal BP–present. Copper enrichment also occurs during the Bronze Age (c. 3150–2800 cal BP). Peaks in other metals do not always correspond with lead and they may have been caused by other land use changes or processes that operate internally within the bog. Although the lead can be attributed to both anthropogenic and geogenic sources, its down profile pattern is in accordance with contamination records elsewhere in Britain and Europe, and the lead enrichment recorded at Raeburn Flow suggests that the Northern Pennine orefield was exploited for metals during the late Iron Age and Roman period.

On runoff generation and the distribution of storage deficits

A number of hydrological models use a distribution function to develop the non-linear rainfall–runoff catchment response. In this study the beta function is applied to represent a distribution of soil moisture storages in conjunction with a fast and slow pathway routing. The BETA3 and BETA4 modules, presented in this paper, have a distribution of discrete storage elements that have variable and redistributed water levels at each timestep. The PDM-BETA5 is an analytical solution with a similar structure to the commonly used probability distribution model (PDM). Model testing was performed on three catchments in the Northern Pennine region in England. The performances of the BETA models were compared with a commonly used formulation of the PDM. The BETA models performed marginally better than the PDM in calibration and parameter estimation was better with the BETA models than for the PDM. The BETA models had a small advantage in validation on the hydrologically fast responding test catchments.

Plumbogummite from Upper Teesdale, County Durham, Northern Pennines, UK

Summary The uncommon, lead-aluminium phosphate hydroxide mineral plumbogummite is reported here, for the first time in the Pennine orefields, derived from a highly oxidized lead-rich vein at Grasshill mines, Upper Teesdale, Co. Durham. The plumbogummite is undoubtedly supergene in origin, but whether it formed along with associated pyromorphite through natural, in situ weathering, or is a post-mining, dump-formed alteration product is unclear.

Abiotic drivers and their interactive effect on the flux and carbon isotope ( 14C and δ 13C) composition of peat-respired CO 2

Feedbacks to global warming may cause terrestrial ecosystems to add to anthropogenic CO 2 emissions, thus exacerbating climate change. The contribution that soil respiration makes to these terrestrial emissions, particularly from carbon-rich soils such as peatlands, is of significant importance and its response to changing climatic conditions is of considerable debate. We collected intact soil cores from an upland blanket bog situated within the northern Pennines, England, UK and investigated the individual and interactive effects of three primary controls on soil organic matter decomposition: (i) temperature (5, 10 and 15 °C); (ii) moisture (50 and 100% field capacity – FC); and (iii) substrate quality, using increasing depth from the surface (0–10, 10–20 and 20–30 cm) as an analogue for increased recalcitrance of soil organic material. Statistical analysis of the results showed that temperature, moisture and substrate quality all significantly affected rates of peat decomposition. Q 10 values indicated that the temperature sensitivity of older/more recalcitrant soil organic matter significantly increased (relative to more labile peat) under reduced soil moisture (50% FC) conditions, but not under 100% FC, suggesting that soil microorganisms decomposing the more recalcitrant soil material preferred more aerated conditions. Radiocarbon analyses revealed that soil decomposers were able to respire older, more recalcitrant soil organic matter and that the source of the material (deduced from the δ 13C analyses) subject to decomposition, changed depending on depth in the peat profile.

Radon concentrations in abandoned mines, Cumbria, UK: safety implications for industrial archaeologists

Abstract. This paper presents a number of surveys performed in a geographical area of the UK, part of which until recently was considered low radon risk. The Cumbrian region was identified by the Building Research Establishment (BRE) in its 1999 guide as an area without a significant radon problem in the built environment. The geology of the region, which includes the Northern Pennine Orefield is varied, but consists of granites, andesites, tuffs, carbonates, sandstones and shales. Mineralisation has taken place (mostly lead and copper ores) primarily along fault and fracture zones, one example being Copper Valley, northwest of Coniston village. This work quantifies the risk of exposure to radon in a number of abandoned mine environments. High radon levels, up to 28 589 Bq m−3, have been measured in parts of one mine. This study demonstrates that industrial archaeologists (such as the Cumbrian Amenity Trust Mining History Society or CATMHS members) and explorers of abandoned mines can be at risk from radon exposure and it proposes a management scheme to allow industrial archaeologists to continue exploration whilst minimising the risk to health from radon.