Mineralisation in SW England

SW England hosts the Cornubian Orefield, a world-class Sn-W-Cu province with subordinate As, Fe, Pb-Zn-Ag, U-Ni-Co and Sb-Au mineralisation as well as a number of other metal occurrences. Furthermore, the industrial mineral kaolinite has been mined extensively across the region. A summary of the major mining districts of SW England is presented in Figure 1.

Mineralisation is intrinsically linked to the structural geology of the area with the vast majority of deposits showing some degree of structural control. The development of the regional fault network and relationship to mineralised structures is illustrated in the Variscan Tectonics section and based on work by Shail and Alexander (1997) and Craig (2018). These are broadly aligned with the tectonic models of Hughes (2018), however, special exception surrounds the timing of D5 structures and mineralisation in the St Just Mining District.

Base metal Devonian-Carboniferous deposits are related to either Volcanic Massive Sulphide (VMS) or SEDimentary EXhalative (SEDEX) style mineralisation and orogenic gold deposits with Sb-Au associated with the Variscan Orogeny. The Permian mineralisation is largely magmatic-hydrothermal and associated with the Cornubian granite batholith. Polymetallic (Sn-Cu-As) lode orientations reflect the regional stress field resulting in NNW-SSE extension for the majority of the lodes, whereas mineralisation on the NW margin of the Land’s End Granite may reflect a change in the regional stress field to ENE-WSW extension (Hughes, 2018; Shail and Alexander, 1997; Shail et al., 2003). Further extension into the Triassic likely reactivated major NW-SE faults connected to Permo-Triassic basins that aided the low-temperature base metal cross-course mineralisation and oblique extension opened the N-S to NNW-SSE structures for mineralisation (Craig, 2018).

Devonian to Carboniferous Mineralisation

Devonian to Carboniferous mineralisation occurred as part of the passive margin succession often forming as small, stratabound deposits of variably concentrated base metals (Leake et al., 1985). Occurrences are often sporadic and difficult to trace along strike resulting in low tonnages. It has been suggested by Jackson et al. (1989) that these deposits could be a significant source of metals for later Permian and Triassic mineralisation. Rift-related, extensional massive sulphide mineralisation across Europe suggests these deposits may be prevalent in pre-Variscan rocks of SW England (Sawkins and Burke, 1980).

Much of the Devonian to Carboniferous mineralisation shows complex structures and mineral textures indicating that the deposits are likely to have been remobilised either during Permian or Triassic mineralisation events. The South Hams of Devon have been extensively explored for massive sulphide deposits, both VMS and SEDEX deposit types relating to Devonian rifting (Leake et al., 1985, 1992; Leake and Norton, 1993) and small Cu-Pb-Zn mineralisation in the Tamar Valley has been attributed to Devonian-Carboniferous VMS mineralisation similar to that of the Iberian Pyrite Belt (Benham et al., 2004). The North Devon Basin has been identified as hosting SEDEX mineralisation similar to the ores found in the Rheinisches Schiefergebirge in Germany (Scrivener and Bennett, 1980) and has been compared to SEDEX mineralisation at Rammelsberg (Benham et al., 2004). However, structural mapping of vein sets and associated fluid inclusion analysis has identified a Triassic origin to the mineralising fluids (Morris, 2016).

Some deposits, such as the Sb-Au mineralisation at Wadebridge, has an orogenic gold mineralisation style which was identified by Clayton et al. (1990) through fluid inclusion analysis. However, some lode structures in the area, suggested by Jackson et al. (1989) to be of cross-course origin, show a more diverse suite of metals and a more complex mineral assemblage including sulphosalts such as bournonite. Clayton et al. (1990) infer higher temperature mineralisation, similar to the Sb-Au veins despite a different fluid chemistry, and attribute sulphosalt formation to basalt decarbonisation during Variscan metamorphism (Clayton, 1993).

Early mineralisation in SW England is therefore diverse, wide-spread, and likely to have undergone significant remobilisation. This is highlighted by further major structures such as the Perran Iron Lode, described in detail by Scrivener et al. (2006), which shows Devonian SEDEX mineralisation, Variscan metamorphism, Permian metasomatism and Triassic remobilisation. Deposits are often small, but their significance as a source of metals for later mineralisation events should not be overlooked.

Permian Mineralisation

Permian mineralisation is dominated by magmatic-hydrothermal fluids directly associated with the emplacement of the Cornubian Batholith. Detailed studies of fluid inclusions form various mineralised areas in SW England have demonstrated that metamorphic, magmatic, hydrothermal and meteoric fluid phases have influenced mineralisation at different times in SW England with five primary fluids identified (Wilkinson, 1991, 1990; Wilkinson et al., 1995). Of these, a magmatic-hydrothermal fluid dominates Permian mineralisation (Fluid 3; Wilkinson et al., 1995). Shail et al. (2003) postulated that mantle-derived volatiles as part of a magmatic fluid component may be a key part of Cu and S enrichment in the region.

The fault network created largely during Variscan convergence and later extension, combined with the generation of multiple fluid phases and the extended period of granite magmatism, weakened the crust and allowed the pervading extensional stress regime to create dilatory fractures and a highly permeable rock mass (Jackson et al., 1989; Shail and Alexander, 1997; Shail et al., 2003; Willis-Richards and Jackson, 1989). There are three stages to Permian magmatic-hydrothermal mineralisation as defined by Chesley et al. (1993), these are described in Table 1. The stages group together different deposit types that largely reflect the changing metal assemblage and may be a reflection of cooling temperatures. A chronology is implicit, but may vary across the region due to diachronous granite emplacement (see Section [sec:PermianMagmatism]).

Table 2i> Summary table of Permian mineralisation styles grouped by stage based on Chesley et al. (1993) and compiled from various sources. 1 - Ussher et al. (1909), 2 - Dines (1956), 3 - Hall (1971), 4 - Jackson (1974), 5 - Jackson and Alderton (1974), 6 - N. J. Jackson (1975a), 7 - N. J. Jackson (1975b), 8 - J McM Moore and N Jackson (1977), 9 - Jackson et al. (1977), 10 - Allman-Ward et al. (1982), 11 - Beer and Scrivener (1982), 12 - Jackson et al. (1982), 13 - Shepherd et al. (1985), 14 - Scrivener et al. (1986), 15 - Bromley and Holl (1986), 16 - Scrivener et al. (1987), 17 - Jackson et al. (1989), 18 - Chesley et al. (1993), 19 - Dominy et al. (1995), 20 - Dominy et al. (1996), 21 - Camm and Dominy (1997), 22 - Camm and Dominy (1999), 23 - Shail et al. (2003), 24 - Scrivener (2006).

Stage	Style	Economic Metals	Gangue Minerals	Temp. (°C)	Examples	Comments	Sources
1	Skarns	Fe, Cu, Sn	Garnet, pyroxene, tourmaline, amphibole, axinite	375-450	Grylls Bunny, Land’s End; Treliver Farm, St Columb; Haytor, Dartmoor	Close proximity to granite	1, 4, 5, 12, 16, 18, 21, 22
2	Pegmatites	Sn, W ±Mo	Quartz, feldspar, muscovite, tourmaline	300-500	Megilligar Rocks	As, Mo, W, Sn, Bi aplite-pegmatite assemblages	15, 17, 18
	Sheeted greisen veins	Sn, W	Quartz, muscovite, tourmaline	300-500	St Michael’s Mount, Cligga Head, Hemerdon	Rare occurrences of Cu, Fe and Sn, native Bi observed at St Michael’s Mount	3, 8, 9, 12, 13, 17, 18, 19
	Tourmaline-bearing veins, lodes, breccia pipes and carbonas	Sn, W	Quartz, muscovite, tourmaline	300-500	Veins and Lodes - ‘Numbered Lodes’, South Crofty; Birch Tor and Vitifer, Dartmoor. Breccia pipe - Wheal Remfry; St Austell. Carbonas - Levant, St Ives and Wheal Roots, Wendron	Cassiterite-bearing quartz-tourmaline veins, deficient in sulphides when proximal to the granite. Breccia pipes can host cassiterite and rutile.	6, 7, 10, 13, 17, 18, 20, 24
3	Sn-bearing polymetallic lodes	Sn, Cu, Pb, Zn, As, Fe	Quartz, feldspar, chlorite, haematite, fluorite	200-400	Wheal Pendarves and Great Flat Lode, Camborne-Redruth district; St Agnes district	Complex history and overprint previous mineralisation. Generally trend ENE-WSW to E-W. NW-SE lodes occur at Land’s End	2, 11, 14, 15, 17, 18, 23, 24

Skarn mineralisation, also known as calc-silicate or “calc-flinta” mineralisation, forms a small portion of the total mineralisation related to Permian magmatic-hydrothermal activity and are often small, low-grade deposits (Jackson et al., 1989). Skarns are found in close proximity to the granite contact and have been described across the peninsula (e.g. Ussher et al., 1909; Camm and Dominy, 1999, 1997; Jackson, 1974; Jackson and Alderton, 1974; Jackson et al., 1982; Scrivener et al., 1987). The protolith prior to skarn mineralisation is usually considered to be a basic igneous intrusion (most likely of Devonian age) where tin mineralisation is often associated with tourmaline and chlorite (Jackson, 1974; Jackson and Alderton, 1974; Jackson et al., 1982).

Mineralised pegmatites are sparse and few have been worked economically. The best examples exist at Megiliggar Rocks where assemblages of lollingite, arsenopyrite and molybdenite with wolframite, cassiterite and native Bi have been noted within banded aplite-pegmatites (Breiter et al., 2018; Bromley and Holl, 1986). Tourmaline-bearing veins, lodes, breccia pipes and carbonas are more widespread. Tourmaline-bearing veins and lodes often host Sn and are pervasive although the best examples can be found at Birch Tor and Vitifer in the Dartmoor Granite (Shepherd et al., 1985) and the “Numbered Lodes” at South Crofty Tin Mine (Jackson et al., 1989; Williamson et al., 2010). Breccia pipes and carbonas are more rare, the most famous being those at Wheal Remfry breccia pipe (Allman-Ward et al., 1982) and the extensive carbona mineralisation exploited in the Wendron Mining District (Dominy et al., 1996; Jackson, 1975; Jackson et al., 1989).

Greisen vein systems, commonly referred to as sheeted vein systems, occur in cupola intrusions such as St Michael’s Mount, Cligga Head and Hemerdon or in the carapace of larger intrusions such as at Bostraze and Goonbarrow in the Land’s End and St Austell granites, respectively (Dominy et al., 1995; Jackson et al., 1989). The centre of greisen veins are generally composed of quartz and host metalliferous ores minerals such as wolframite and to a lesser extent cassiterite with accessory arsenopyrite (Hall, 1971; Jackson et al., 1977, 1989; Moore and Jackson, 1977). Sulphide minerals such as chalcopyrite and pyrite as well as stannite and native bismuth are also found in some deposits such as St Michael’s Mount (Dominy et al., 1995). Fluid inclusion data imply that, whilst showing structural simplicity, mineralisation may have been complex with a broad temperature range and distinct mixing of variable salinity fluids (Dominy et al., 1995). Furthermore, the Hemerdon deposit appears to be distinct from Cligga Head and St Michael’s Mount in that it has multiple vein sets and is largely deficient in arsenopyrite. Fluid inclusion studies also indicate a vapour phase separation which is unique to the deposit (Shepherd et al., 1985).

Polymetallic lodes display a complex history of magmatic-hydrothermal activity (Jackson et al., 1989; Scrivener, 2006). The lodes are dominated by generally high angle extensional faults or cavities but can be lower angle (e.g. Great Flat Lode, Camborne-Redruth Mining District). These lodes generally trend ENE-WSW to E-W although local variations occur such as NW-SE lodes on the northern margin of the Land’s End Granite (Dines, 1956; Jackson et al., 1989; Shepherd et al., 1985). Some areas show that polymetallic mineralisation overprints previous sheeted greisen veins or tourmaline-bearing Sn veins (Dines, 1956) demonstrating it is likely to be a later mineralisation event at the deposit scale.

Triassic Mineralisation

Triassic mineralisation is characterised by N-S to NNW-SSE trending cross-course mineralisation and forms an important deposit type for low temperature base metals, particularly Pb and Zn (Jackson et al., 1989; Scrivener et al., 1994). Lodes from the Tamar Valley have been dated by Rb-Sr isotope analysis of fluid inclusions. The study of N-S trending Pb-Zn-F mineralisation in the area yielded an age of 236 $\pm$ 3 Ma (Scrivener et al., 1994). Fluid inclusions demonstrate an affinity to oil-field brines with an evaporitic origin and most likely sourced from the Permo-Triassic basins (Gleeson et al., 2000, 2001; Scrivener et al., 1994). An evaporitic source infers seawater incursion which has been correlated to the Late Triassic (Gleeson et al., 2001), however, this may also indicate the Rb-Sr dating by Scrivener et al. (1994) requires refinement. The N-S to NNW-SSE structures are spatially related to significant NW-SE dextral faults; partial reactivation along these faults during Triassic extension may have acted as a fluid pathway from the sedimentary basins (Gleeson et al., 2000; Jackson et al., 1989; Stanley and Criddle, 1990).

The source of metals for Triassic mineralisation is unproven. The highly variable nature described by Craig (2018) may be a reflection of local controls on mineralisation (Gleeson et al., 2000). Local variations include Sb-bearing cross-courses in the Loddiswell area and at Herodsfoot Mine (Dines, 1956; Stanley and Criddle, 1990) which may be the result of remobilisation of earlier Devonian-Carboniferous Sb mineralisation similar to the Wadebridge area (Clayton et al., 1990). Other areas have been worked for U, Co and Ni which often occur proximal to granite plutons including mines such as South Terras, Dolcoath (South Crofty Mine), Roskrow United, East Pool and Agar, Great Dowgas, St Austell Consol, Chance, Pengelly and Fowey Consols (Dines, 1956); all of which are close to the granite margin. The variation based on the proximity to granite may indicate that the batholith may have provided a heat source necessary for an extended period of mineralisation (Jackson et al., 1989; Tammemagi and Smith, 1975; Tammemagi and Wheildon, 1974). Fluid inclusion studies at Porthleven and Menheniot support the suggestion of a heat source external to the source basins (Gleeson et al., 2000) and it is likely that tectonic activity was a major contribution to mobilising the fluids and creating permissive fractures.

Granite Kaolinisation

Kaolinite is an industrial mineral that has been mined historically from most of the granite plutons and remains an important commodity, however, production is now limited to the St Austell Granite and SW Dartmoor at Lee Moor. Economic deposits of kaolinised granite in SW England are not pervasive and generally associated with multiple intrusions and major fault zones (Jackson et al., 1989; Scrivener, 2006). Studies of kaolinisation mechanisms are focussed on the St Austell Granite; the main extractive centre. Early interpretations suggested that kaolinisation was a supergene process (Sheppard, 1977). Jackson et al. (1989) postulated a hydrothermal component to kaolinisation, however, it was not until extensive research by Psyrillos et al. (2003) that a mineralisation model was developed (Figure 2. Work by Psyrillos et al. (2003) resulted in a new model where hydrothermal kaolinite formed in extensional open fractures within the granite body at temperatures between 50 to 100 $^{\circ}$C and approximately 1 km depth. The hydrothermal activity is considered to be of mid-Jurassic age and relate to early Atlantic rifting. Unroofing in the Cretaceous allowed the percolation of meteoric fluids resulting in subsequent supergene alteration and re-equilibration of hydrogen isotopes.

The model of Cretaceous unroofing for the St Austell Granite is based on the assumption that unroofing of the Dartmoor Granite is synchronous. The evidence of Cretaceous unroofing of the Dartmoor Granite is based on detrital studies in the English Channel (Cosgrove and Salter, 1966), however, conglomerates near Newton St Cyres [SX 8829 9981] show felsic clasts of presumed Dartmoor affinity and have been dated using palynomorphs to mid- to late-Permian (Dangerfield and Hawkes, 1969; Edwards, 1999; Scrivener and McVicar Wright, 2014). Therefore it is likely that two phases of unroofing occurred, although, this does not preclude the possibility that the St Austell Granite was indeed unroofed later, during the Cretaceous.

References

Allman-Ward, P., Halls, C., Rankin, A.H., Bristow, C.M., 1982. An intrusive hydrothermal breccia body at Wheal Remfry in the western part of the St Austell granite pluton, Cornwall, in: Evans, A.M. (Ed.), Metallization Associated with Acid Magmatism. John Wiley & Sons Ltd, pp. 1–28.

Benham, A.J., McEvoy, F.M., Rollin, K.E., 2004. Potential for stratiform massive sulphide mineralisation in south-west England. Applied Earth Science 113, 227–246. https://doi.org/10.1179/174327504X27215

Breiter, K., Ďurišová, J., Hrstka, T., Korbelová, Z., Vašinová Galiová, M., Müller, A., Simons, B., Shail, R., Williamson, B., Davies, J., 2018. The transition from granite to banded aplite-pegmatite sheet complexes: An example from Megiliggar rocks, Tregonning topaz granite, Cornwall. Lithos 303, 370–388. https://doi.org/10.1016/j.lithos.2018.01.010

Bromley, A.V., Holl, J., 1986. Tin mineralisation in southwest England, in: Wills, B.A., Barley, R.W. (Eds.), Mineral Processing at a Crossroads: Problems and Prospects. Martinus Nijhoff, Lancaster, pp. 195–262.

Camm, G.S., Dominy, S.C., 1999. Tin mineralization and structure at Treliver, St. Austell, mid-Cornwall. Geoscience in South-West England 9, 370–373.

Camm, G.S., Dominy, S.C., 1997. Metasediment-hosted tin mineralization in the Indian Queens area, mid-Cornwall. Proceedings of the Ussher Society 9, 211–214.

Chesley, J.T., Halliday, A.N., Snee, L.W., Mezger, K., Shepherd, T.J., Scrivener, R.C., 1993. Thermochronology of the Cornubian batholith in southwest England: Implications for pluton emplacement and protracted hydrothermal mineralization. Geochimica et Cosmochimica Acta 57, 1817–1835.

Clayton, R., 1993. Basalt carbonatisation and its implications for antimony mineralisation in north Cornwall. Proceedings of the Ussher Society 8, 105–111.

Clayton, R.E., Scrivener, R.C., Stanley, C.J., 1990. Mineralogical and preliminary fluid inclusion studies of lead-antimony mineralisation in north Cornwall. Proceedings of the Ussher Society 7, 258–262.

Cosgrove, M.E., Salter, D.L., 1966. The stratigraphic distribution of kaolinite in the post-Armorican formations of south-west England. Proceedings of the Ussher Society 1, 249–252.

Craig, F.D.A., 2018. The characterisation of Cornish crosscourses (MSc Dissertation). University of Exeter.

Dangerfield, J., Hawkes, J.R., 1969. Unroofing of the Dartmoor Granite and possible consequences with regard to mineralization. Proceedings of the Ussher Society 2, 122–131.

Dines, H.G., 1956. The Metalliferous mining region of south-west England. Economic Memoirs of the Geological Survey of Great Britain.

Dominy, S.C., Camm, G.S., Bussell, M.A., 1996. Characteristics and development of carbona-style replacement tin mineralization in west Cornwall. Proceedings of the Ussher Society 9, 97–104.

Dominy, S.C., Camm, G.S., Bussell, M.A., Bennett, T.S., 1995. The structure and paragenetic evolution of cassiterite mineralized veins at Rosevale Mine, Zennor, West Cornwall. Proceedings of the Ussher Society 8, 374–378.

Edwards, R.A., 1999. The Minehead District - A Concise Account of the Geology. Memoir of the British Geological Survey, Sheet 278; part of 294. England; Wales.

Gleeson, S.A., Wilkinson, J.J., Shaw, H.F., Herrington, R.J., 2000. Post-magmatic hydrothermal circulation and the origin of base metal mineralization, Cornwall, UK. Journal of the Geological Society, London 157, 589–600. https://doi.org/10.1144/jgs.157.3.589

Gleeson, S.A., Wilkinson, J.J., Stuart, F.M., Banks, D.A., 2001. The origin and evolution of base metal mineralising brines and hydrothermal fluids, South Cornwall, UK. Geochimica et Cosochimica Acta 65, 2067–2079.

Hall, A., 1971. Greisenisation in the granite of Cligga Head, Cornwall. Proceedings of the Geologists’ Association 82, 209–230.

Hughes, S.P., 2018. The tectonomagmatic evolution of the Land’s End Granite (Unpublished PhD Thesis). University of Exeter.

Jackson, N.J., 1975. “Carbonas” - a review. Proceedings of the Ussher Society 3, 218–219.

Jackson, N.J., 1974. Grylls Bunny, a “tin floor” at Botallack. Proceedings of the Ussher Society 3, 186–188.

Jackson, N.J., Alderton, D.H.M., 1974. Discordant calc-silicate bodies in the Botallack area. Proceedings of the Ussher Society 3, 123–127.

Jackson, N.J., Halliday, A.N., Sheppard, S.M.F., Mitchell, J.G., 1982. Hydrothermal Activity in the St Just Mining District, Cornwall, England, in: Evans, A.M. (Ed.), Metallization Associated with Acid Magmatism. John Wiley & Sons Ltd, pp. 137–180.

Jackson, N.J., Moore, J.M., Rankin, A.H., 1977. Fluid inclusions and mineralization at Cligga Head, Cornwall, England. Journal of the Geological Society, London 134, 343–349.

Jackson, N.J., Willis-Richards, J., Manning, D.A.C., Sams, M.S., 1989. Evolution of the Cornubian ore field, Southwest England; Part II, Mineral deposits and ore-forming processes. Economic Geology 84, 1101–1133.

Leake, R.C., Brown, M.J., Smith, K., Rollin, K.E., Kimbell, G.S., Cameron, D.G., Roberts, P.D., Beddoe-Stephens, B.W., 1985. Volanogenic and exhalative mineralisation within Devonian rocks of the South Hams district of Devon. Mineral Reconnaissance Programme Report. British Geological Survey, No. 79.

Leake, R.C., Cameron, D.G., Bland, D.J., Styles, M.T., Rollin, K.E., 1992. Exploration for gold in the South Hams district of Devon. Mineral Reconnaissance Programme Report, Institute of Geological Sciences, No. 121.

Leake, R.C., Norton, G.E., 1993. Mineralisation in the Middle Devonian volcanic belt and associated rocks of South Devon. Mineral Reconnaissance Programme Report, Institute of Geological Sciences, No. 129.

Moore, J.M., Jackson, N., 1977. Structure and mineralization in the Cligga granite stock, Cornwall. Journal of the Geological Society, London 133, 467–480. https://doi.org/10.1144/gsjgs.133.5.0467

Morris, D., 2016. An Integrative Study into the Structural Controls of Pb-Zn Mineralisation in the North Devon Basin using Tellus South-West Project Data: Combe Martin, Devon (MSc Dissertation). Camborne School of Mines, University of Exeter.

Psyrillos, A., Burley, S.D., Manning, D.A.C., Fallick, A.E., 2003. Coupled mineral-fluid evolution of a basin and high: kaolinization in the SW England granites in relation to the development of the Plymouth Basin. Geological Society, London, Special Publications 214, 175–195. https://doi.org/10.1144/GSL.SP.2003.214.01.11

Sawkins, F.J., Burke, K., 1980. Extensional Tectonics and Mid-Paleozoic Massive Sulfide Occurrence in Europe. Geologische Rundschau 69, 349–360.

Scrivener, R.C., 2006. Cornubian granites and mineralization of SW England, in: Brenchley, P.J., Rawson, P.F. (Eds.), The Geology of England and Wales. The Geological Society, London, pp. 257–268.

Scrivener, R.C., Bennett, M.J., 1980. Ore genesis and controls of mineralisation in the Upper Palaeozoic rocks of north Devon. Proceedings of the Ussher Society 54–58.

Scrivener, R.C., Cooper, B.V., George, M.C., 1987. Mineralogy and paragenesis of the Haytor iron ore deposit. Proceedings of the Ussher Society 6, 558.

Scrivener, R.C., Darbyshire, D.P.F., Shepherd, T.J., 1994. Timing and significance of crosscourse mineralization in SW England. Journal of the Geological Society, London 151, 587–590.

Scrivener, R.C., Grant, J.B., Hollick, L.M., Smith, C.W., 2006. Nature and origin of the Great Perran Iron Lode, Perranporth area, Cornwall. Geoscience in South-West England 11, 255–256.

Scrivener, R., McVicar Wright, S., 2014. Dartmoor Granite and the Crediton Graben, in: Shail, R., Andersen, J., Simons, B., Williamson, B.J. (Eds.), EUROGRANITES 2014: Granites and Mineralisation of Sw England. Field Excursion Guidebook 12th-18th July 2014, pp. 63–84.

Shail, R.K., Alexander, A.C., 1997. Late Carboniferous to Triassic reactivation of Variscan basement in the western English Channel: evidence from onshore exposures in south Cornwall. Journal of the Geological Society, London 154, 163–168. https://doi.org/10.1144/gsjgs.154.1.0163

Shail, R.K., Stuart, F.M., Wilkinson, J.J., Boyce, A.J., 2003. The role of post-Variscan extensional tectonics and mantle melting in the generation of the Lower Permian granites and giant W-As-Sn-Cu-Zn-Pb orefield of SW England. Applied Earth Science 112, 127–129.

Shail, R., Scrivener, R., Simons, B., Müller, A., Andersen, J., Williamson, B.J., Halls, C., Hughes, S., 2014. Early Permian post-Variscan magmatism, in: Shail, R., Andersen, J., Simons, B., Williamson, B.J. (Eds.), EUROGRANITES 2014: Granites and Mineralisation of Sw England. Field Excursion Guidebook 12th-18th July 2014, pp. 14–36.

Shepherd, T.J., Miller, M.F., Scrivener, R.C., Darbyshire, D.P.F., 1985. Hydrothermal fluid evolution in relation to mineralization in southwest England with special reference to the Dartmoor-Bodmin area, in: High Heat Production (Hhp) Granites, Hydrothermal Circulation and Ore Genesis Conference, London. Institution of Mining; Metallurgy (Great Britain), pp. 345–364.

Sheppard, S.M.F., 1977. The Cornubian batholith, SW England: D/H and 18O/16O studies of kaolinite and other alteration minerals. Journal of the Geological Society, London 133, 573–591. https://doi.org/10.1144/gsjgs.133.6.0573

Stanley, C.J., Criddle, A.J., 1990. Precious and Base Metal Selenide Mineralization at Hope’s Nose, Torquay, Devon. Mineralogical Magazine 54, 485–493.

Tammemagi, H.Y., Smith, N.L., 1975. A radiogeologic study of the granites of SW. England. Journal of the Geological Society, London 131, 415–427. https://doi.org/10.1144/gsjgs.131.4.0415

Tammemagi, H.Y., Wheildon, J., 1974. Terrestrial Heat Flow and Heat Generation in South-west England. Geophysical Journal of the Royal Astronomical Society 38, 83–94.

Ussher, W.A.E., Barrow, G., MacAlister, D.A., 1909. The geology of the country around Bodmin and St. Austell. Memoirs of the Geological Survey, Explanation of Sheet 347. England; Wales.

Wilkinson, J.J., 1991. Volatile production during contact metamorphism: the role of organic matter in pelites. Journal of the Geological Society, London 148, 731–736.

Wilkinson, J.J., 1990. The role of metamorphic fluids in the development of the Cornubian orefield: fluid inclusion evidence from south Cornwall. Mineralogical Magazine 54, 219–230.

Wilkinson, J.J., Jenkin, G.R.T., Fallick, A.E., Foster, R.P., 1995. Oxygen and hydrogen isotopic evolution of Variscan crustal fluids, south Cornwall, U.K. Chemical Geology 123, 239–254.

Williamson, B.J., Müller, A., Shail, R.K., 2010. Source and partitioning of B and Sn in the Cornubian batholith of southwest England. Ore Geology Reviews 38, 1–8. https://doi.org/10.1016/j.oregeorev.2010.05.002

Willis-Richards, J., Jackson, N.J., 1989. Evolution of the Cornubian Ore Field, Southwest England: Part I. Batholith Modeling and Ore Distribution. Economic Geology 84, 1078–1100.