Content and licensingview original scan buy a printed copy

Geology of the New Cumnock district — a brief explanation of the geological map, 1:50 000 Sheet 15W New Cumnock

R A Smith

Bibliographic reference: Smith, R A. 1999. Geology of the New Cumnock district — a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 15W New Cumnock (Scotland).

Keyworth, Nottingham:British Geological Survey, 1999. © NERC 2004 All rights reserved

Copyright in materials derived from the British Geological Survey's work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. Contact the BGS Intellectual Property Rights Section, British Geological Survey, Keyworth, email ipr@bgs.ac.uk. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract.

(Front cover) Loch o'th'Lowes with the New Cumnock coalfield in the low ground and the former Knockshinnoch colliery and restored opencast in the distance. Glen Afton cuts through Ordovician rocks on the skyline (taken from [NS 600 152]) (D5369).

(Rear cover)

Notes

The word 'district' refers to the area of Sheet 15W New Cumnock. National grid references are given in square brackets; unless prefixed by NX, all lie within 100 km square NS. Symbols in round brackets after lithostratigraphical names are the same as those used on the geological map Sheet 15W.

Acknowledgements

This Sheet Explanation was compiled by D G Woodhall, Divisional Editor, Scotland and Northern England Unit, Edinburgh, and is based solely on the approved version of the Sheet Description for the New Cumnock district authored by R A Smith. Full acknowledgements are to be found within the Sheet Description.

The grid, where it is used on figures, is the National Grid taken from Ordnance Survey mapping.

© Crown copyright reserved Ordnance Survey licence no. GD272191/1999.

Geology of the New Cumnock district (summary from rear cover)

(Rear cover)

The New Cumnock district lies astride the Southern Upland Fault, taking in part of the Midland Valley of Scotland and part of the Southern Uplands massif. Industries in this area were formerly based on geological resources such as coal, ironstone and limestone, but at present only coal is being extracted.

Black mudstones and basic volcanic rocks are the oldest rocks in the district and are Arenig to possibly Llanvirn in age. They are overlain by Caradocian greywacke sandstones with some intercalated volcanic rocks in a series of fault-bounded blocks. The fault blocks were deformed during the Caledonian orogeny.

In the Midland Valley, Silurian strata are exposed in the cores of faulted periclines. Llandovery greywacke sandstones are succeeded by Wenlock terrestrial red beds that are overlain disconformably by a red bed sequence of Siluro-Devonian age. Subsequent sedimentation was predominantly volcaniclastic. At about this time a series of granodioritic complexes were intruded into the Ordovician rocks of the Southern Uplands massif.

Carboniferous rocks of Dinantian to Westphalian age are mainly fluviatile and fluviodeltaic in origin with pedogenic carbonates, and some volcanic rocks (Strathclyde Group). Seatrock and coal is a characteristic of the Namurian and Westphalian rocks (Clackmannan and Coal Measure groups). Contemporaneous faulting influenced the thickness and facies of the Carboniferous strata, and has given rise to local unconformities.

No Permian sedimentary rocks are present, but the reddening of the upper part of the Coal Measures may be due to oxidation associated with Permian weathering and erosion. A suite alkaline sills and dykes of early Permian age is probably related to volcanic activity represented by olivine basalt lavas and by vents cutting Westphalian rocks. There are some minor dykes and sills of Palaeogene age.

During the Pleistocene glaciation the district lay at the confluence of ice from the Scottish Highlands and ice moving northwards from the Southern Uplands. Alluvium and peat accumulated during the warmer and wetter climate of the Holocene.

Chapter 1 Introduction

The New Cumnock district is divided into the Midland Valley and Southern Uplands terranes by the Southern Upland Fault. The Midland Valley terrane lies north of the fault and is occupied predominantly by Upper Palaeozoic rocks forming rolling hills and moorland with the lower ground around New Cumnock and Muirkirk underlain by coal-bearing rocks. The higher ground of the Southern Uplands terrane is mainly formed of Lower Palaeozoic rocks interrupted by an Upper Carboniferous outlier north-west of Sanquhar. The main population centres are the towns of Muirkirk, New Cumnock and Sanquhar, and a few villages such as Kirkconnel. These are widely scattered and are separated by areas of agricultural land and wide expanses of moorland.

The bedrock consists mostly of sedimentary rocks of Ordovician, Silurian, Devonian, and Carboniferous age, deposited at various times between about 480 and 310 million years ago (Figure 1). Black mudstones and greywacke sandstone turbidites accumulated in deep water during the Ordovician and the earliest part of the Silurian (Llandovery), but later in the Silurian (Wenlock) gave way to terrestrial (fluviatile) red-bed sequences. Following a substantial period of deformation, uplift and erosion during the middle and late Devonian, deposition resumed during the Carboniferous. Marine, deltaic and fluviatile mudstones, siltstones, sandstones and limestones were deposited, along with some pedogenic carbonate, seatrocks and coal. There are volcanic rocks, with contemporaneous intrusive igneous rocks of Ordovician, early Devonian, early Carboniferous and early Permian age (about 285 Ma) together with a few minor intrusions of Palaeogene age (52 Ma). The Carboniferous and early Permian rocks were subjected to uplift, folding and faulting during the Permian (Hercynian orogeny). A major unconformity exists between the youngest bedrock (Permo–Carboniferous) and extensive drift deposits of Quaternary age. These deposits date mainly from the most recent of the major Quaternary (Pleistocene) glaciations, when the district was buried beneath an ice sheet. As the ice melted, till was deposited, mainly on the lower ground, and hummocky moraines and outwash sands and gravels were deposited locally along the river valleys. Meltwater produced marginal drainage channels, which remain today as small eskers and kames. A minor readvance affected the higher glens of the Southern Uplands. Small valley glaciers deposited hummocky moraines. Postglacial (Holocene) rivers reworked glacial debris creating terraced alluvium in the larger valleys. Small alluvial fans have built up at the junctions of side valleys. Peat mosses formed on poorly drained slopes and hollows.

History of research

The original geological survey of the area was published at the 1:63 360 scale in 1870, with an accompanying memoir (Geikie et al., 1871). Peach and Horne (1899) made a revision of the Lower Palaeozoic rocks. The Upper Palaeozoic geology was revised by the Geological Survey in the 1920s and 1930s, and a new 1:63 360 scale map was published (1937). Economic geology memoirs were produced covering the Muirkirk area (Eyles et al., 1930), New Cumnock area (Simpson and MacGregor, 1932) and the Sanquhar Basin (Simpson and Richey, 1936). A resurvey of the Clackmannan Group and Coal Measures by Lumsden (1964; 1965; 1967a; 1967c) and Davies (1970; 1972) was incorporated into a 1:50 000 solid edition of Sheet 15W (1986). A revised drift map at 1:50 000 was published in 1982.

Rolfe (1961), Rolfe and Fritz (1966) and Heinz and Loeschke (1988) have published details of the Silurian stratigraphy and palaeontology in the Hagshaw Hills Inlier. Bluck (1978), and his students (McGiven, 1968; Syba, 1989) studied the sedimentology and provenance of the overlying Lower Old Red Sandstone (Lanark Group). Floyd (1994) and Smith (1995c) have reviewed the main structural features including the Southern Upland Fault. Burgess (1961) described the pedogenic carbonate (cornstone) at the base of the Kinnesswood Formation. The Ordovician rocks in the Southern Uplands were described in the context of accretionary prism models (McMurtry, 1980a; b; Hepworth et al., 1982). Later models of the Southern Uplands involving either a back-arc basin (Stone et al., 1987) or an extending basin (Armstrong et al., 1996) have been proposed.

Chapter 2 Geological description

Ordovician of the Southern Uplands terrane

Ordovician rocks crop out extensively within the Southern Upland terrane (Figure 2). The Crawford Group (CRFD) consists of faulted lenses of red and grey bedded chert, cherty mudstone and volcaniclastic rocks, with some slivers of altered basic lavas, and locally dolerite, all of which crop out along the north-west side of the Leadhills Fault. The cherty mudstones are of uncertain age, but equivalent strata immediately east of the district (Sheet 15E) have yielded Arenig and Llanvirn conodonts (Floyd, 1996). Overlying black and dark grey mudstones of the Moffat Shale Group (MFS) are interpreted as the deposits of suspension sedimentation (hemipelagite) in deep water. They are cherty, contain disseminated pyrite, and are locally laminated. Graptolite faunas are of Caradoc age (Hughes, 1989; Rushton, 1995; 1996).

Most Ordovician rocks within the district form part of the Leadhills Supergroup (Figure 3). The Tappins Group occupies the tract between the Southern Upland and Carcow faults, and probably incorporates the oldest rocks of the supergroup (Floyd, 1999). The group is represented in the district by the Marchburn Formation (MCHB) (Figure 3), which young overall to the north-west (Floyd, 1982; 1996; 1999). No diagnostic fossils have been found within the district, but those from adjacent areas are indicative of the N. gracilis Biozone (Floyd, 1996).

The Bail Hill Volcanic and Barrhill groups occupy the tract between the Carcow and Leadhills faults. The Bail Hill Volcanic Group crops out on Bail Hill [NS 760 142], and consists of alkaline within-plate (oceanic) basalts (Phillips and Smith, 1996; McMurtry, 1980a). The Cat Cleuch Formation (CACL) consists mostly of pyroxene-phyric basalt lavas, with some intercalated volcaniclastic rocks, which rest conformably on slightly baked graptolitic mudstones. The Peat Rig Formation (PERG) dominates the Bail Hill Volcanic Group and consists of lavas containing numerous plagioclase microphenocrysts, and subordinate phenocrysts of amphibole, clinopyroxene and apatite. Biotite phenocrysts are particularly common within the upper part of the formation. Volcaniclastic rocks, in the form of weathered, poorly bedded lapilli-tuffs and volcanic breccias, occur mainly in the upper part of the formation. The Grain Burn Member (GRAB) is a distinct sequence of amphibole-porphyritic lavas (McMurtry, 1980a; Floyd, 1996).

The Kirkcolm Formation (KKF) of the Barrhill Group is at least 3 km thick, and locally interdigitates with the Bail Hill Volcanic Group. The volcaniclastic rocks of the Stoodfold Member (STOD) crop out north-east of the volcanic group, from which they appear to have been derived. The Spothfore Member (SPOT) is up to 700 m thick but thins away from the Bail Hill Volcanic Group; it appears to have lapped onto the Bail Hill volcano after it became extinct. Some of the volcaniclastic breccias of the Poltallan Member (POLT) contain clasts of sandstone as well as amygdaloidal lava. The Galdenoch Formation (GDF) is approximately 70 m thick and is intercalated with the Kirkholm Formation. The Blackcraig Formation (BLKC) rests conformably on the Kirkholm Formation, as seen in Craig Burn [NS 640 055], but the top is faulted (Floyd, 1996). The formation is petrographically distinct from the Galdenoch Formation, but is of approximately the same age (N. gracilis–C. peltifer biozones).

The Scaur Group occupies the tract between the Leadhills and Fardingmullach faults and includes the Portpatrick (PPF) and Glenwhargen (GWH) formations (Figure 3). The volcaniclastic turbidites of the Portpatrick Formation are over 2 km thick, and contain abundant andesitic detritus, accompanied by fresh detrital pyroxene and hornblende (Styles et al., 1989; 1995). The formation rests on Moffat Shale Group strata containing graptolites up to the P. linearis Biozone. The greywacke sandstones of the Glenwhargen Formation are up to 150 m thick and interfinger with the Portpatrick Formation. South of the Fardingmullach Fault, the Leadhills Supergroup is represented by the Shinnel Formation (SHIN), which consists of sandstones within a background of thick laminated siltstones and mudstones. The rare thick conglomerate units contain mudstone, igneous and metamorphic clasts.

Silurian of the Midland Valley terrane

Silurian rocks in the Midland Valley terrane form the Hagshaw Hills (Hagshaw, Glenbuck and Monks Water groups), and the Lesmahagow (Priesthill and Dungavel groups) inliers. Details are given in Paterson et al. (1998), consequently only a summary is given below and in (Figure 4).

The base of the Smithy Burn Siltstone Formation (SMBS) (Hagshaw Group) is faulted. The turbidites of the succeeding Ree Burn Formation (RBN) display sole structures indicating flow from the south. Some contain clasts with a shallow-marine shelly fauna (Rolfe, 1961). The Parishholm Conglomerate Formation (PHM) contains rounded to subangular clasts of fine-grained acid and basic igneous rocks, red and green chert, quartzite, vein quartz and intrabasinal greywacke fragments. The Hareshaw Conglomerate Formation (HRSC) (Monks Water Group) contains rounded pebble and cobble-sized clasts of vein quartz and quartzite, along with those of fine-grained and porphyritic igneous rocks, granite, schist, gneiss, chert and mudstone. McGiven (1968) interpreted the formation as alluvial fan deposits derived from the south-east. The Ponesk Burn Formation (PSKB) (Priesthill Group) occurs in a small partly faulted inlier [NS 675 280] to the south of the Lesmahagow Inlier. The strata dip and young to the north-west, and resemble those of the Ree Burn Formation in the Hagshaw Hills inlier (Paterson et al., 1998). The Plewland Sandstone Formation (PLWS) (Dungavel Group) crops out on the northern edge of the district [NS 640 280], and forms part of the Lesmahagow Inlier.

Siluro–Devonian of the Midland Valley terrane

The Siluro–Devonian rocks of the Midland Valley terrane consists of about 3000 m of sedimentary and volcanic rocks, which comprise the Lanark Group (Figure 5). The Greywacke Conglomerate Formation (GRWC) rests disconformably on the Quarry Arenite and Plewland Sandstone formations of the Hagshaw Hills and Lesmahagow inliers respectively. The formation varies considerably in thickness from 25 m to nearly 500 m. It is interpreted as alluvial fan deposits that accumulated from sheet floods derived from the south-east (McGiven, 1968). The geochemistry of the clasts (Syba, 1989) suggests that they probably came from a cryptic source within the Midland Valley of Scotland. The Swanshaw Formation (SWAS) is up to 700 m thick and the sandstones have a similar provenance to those of the Greywacke Conglomerate Formation.

The lavas of the Duneaton Volcanic Formation (DNV) range from aphyric to plagioclase- pyroxene-porphyritic, and incorporate thick amygdaloidal and auto-brecciated zones. Some of the andesites are hornblende bearing. A geochemical study (Phillips, 1994a) showed that the majority are basaltic andesites typical of calc-alkaline suites, and therefore similar to the Lower Devonian volcanic rocks elsewhere in the Midland Valley of Scotland (Thirlwall, 1981). The intercalated volcaniclastic sandstones and breccias are variable in thickness and composition; they were locally sourced and probably deposited from debris flows.

The maximum thickness (1000 m) of the Auchtitench Formation (AUC) (Smith, 1993; 1994; 1995a) is what remains after the uplift and erosion that followed middle Devonian tectonism. Conglomerates occur in coarsening upwards beds (Plate 1); they contain mainly rounded pebbles and cobbles of andesitic and basaltic lava in a sandstone matrix. Near the Southern Upland Fault, the conglomerates locally contain lava boulders up to 1.2 m across, and local clast imbrications indicate northerly flowing palaeocurrents. The upper part of the formation contains other detrital material sourced from either within the Midland Valley or Southern Uplands.

Carboniferous

The Inverclyde Group rests unconformably on Lower Devonian rocks. The basal cornstone of the Kinnesswood Formation (KNW) (Figure 6) represents a thick caliche developed in a palaeosol (Burgess, 1961). Sandstone units in the rest of the formation display cross-bedding, and some fine upwards into thinly interbedded finer grained sandstone, siltstone and silty mudstone. There are some slightly calcareous sandstones containing pebbles, up 2 cm across, of angular to subrounded chert, quartz, cornstone, silicified sandstone, greenish siltstone and silty mudstone. Near Garpel Water [NS 70 23], the Kinnesswood Formation represents the whole of the Inverclyde Group. This is because of either facies changes within the group or an unconformity with the overlying Strathclyde Group. The thickness of the succession favours the former, however, an unconformity is indicated south-east of the Kennox Fault [NS 79 25], where the Strathclyde Group oversteps the Kinnesswood Formation to rest on older rocks. The 'cementstone' beds of the Ballagan Formation (BGN) are up to 0.2 m thick and developed as algal mats. The Clyde Sandstone Formation (CYD) succeeds the Ballagan Formation, on the basis of evidence from the Limmerhaugh No. 10 Borehole.

The Strathclyde Group cannot be sub-divided in the district. In places, in the west of the district, for example beside the River Ayr [NS 603 258], basaltic lavas (miB) and/or volcaniclastic rocks occur at or near the base of the group, and may correlate with the Clyde Plateau Lava Formation. Around Gasswater Head e.g. [NS 691 214] the group consists mainly of yellow-brown, greenish or red-brown sandstone with some coarse-grained to conglomeratic beds. The latter contain angular to subrounded pebbles of chert, quartz and greywacke sandstone that were probably derived from the Southern Uplands to the south. Conglomerates in Glenmuir Burn [NS 625 207] are intercalated with sandstones containing carbonaceous flakes and are considered to be part of the Strathclyde Group.

The Muirkirk Under Limestone (Paterson and Hall, 1986) occurs in the upper part of the group. It is up to 0.9 m thick, rubbly bedded and packed with brachiopods (Gigantoproductid), corals and other marine fossils (Davies, 1972). In the Polwhannan Burn [NS 704 215] it was formerly considered to be the Hawthorn Limestone (Davies, 1972).

The Clackmannan Group (CKN) occurs as a condensed sequence on the western side of the Sanquhar Basin, where it was formerly known as the Millstone Grit Series (Davies, 1970). It incorporates the Polhote Marine Band, and the top of the group is taken at Tait's Marine Band (Davies, 1970) which was identified in the Fauldhead Underground Borehole [NS 7202 1346].

The Lower Limestone Formation (LLGS) comprises the strata between the base of the Hawthorn Limestone to the top of the McDonald Limestones (Davies, 1972). The basal Hawthorn Limestone Member is typically a fossiliferous, fine-grained limestone, up to 13.5 m thick, with calcareous silty mudstone intercalations. In the Muirkirk area, the upper part is nodular. In the Douglas Basin, in Kennox Water [NS 7780 2484], the equivalent Douglas Main Limestone (Lumsden, 1967a) consists of 2 m of limestone, overlying up to 6 m of calcareous silty mudstone, resting on 1 m of bioclastic limestone. Sandstone fining up into a seat-clay overlain by a thin coal commonly succeeds the Hawthorn Limestone. Overlying dark grey mudstones incorporate the shelly Muirkirk Wee Limestone, up to 1.3 m thick which is correlated with the Douglas Wee Limestone (Davies, 1972). Above the Muirkirk Wee Limestone, there are several metres of grey mudstone. The overlying McDonald Limestones Member consists of up to four limestone beds, with interbedded calcareous siltstones, altogether up to 9 m thick (Plate 2). The topmost limestone is taken to be equivalent to the Top Hosie Limestone found elsewhere in the Midland Valley (Wilson, 1989).

The Limestone Coal Formation (LSC) includes strata between the top of the McDonald Limestones and the base of the Index Limestone. Correlations within the formation are shown in (Figure 7). The Johnstone Shell Bed and Black Metals Marine Band have yielded marine faunas of calcareous brachiopods and Lingula sp. (Davies, 1972). Above the latter marine band, there are coarsening-upwards cycles capped by substantial coals some of which are affected by seam-splitting (Davies, 1972). Above the uppermost coal, the Ell Coal, some mudstone beds locally contain Lingula sp., harbinging the major marine transgression represented by the Index Limestone.

The Upper Limestone Formation (ULGS) includes the strata between the base of the Index Limestone and the unconformity at the base of the Passage Formation (Figure 8). In the Muirkirk area, the basal bioclastic Index Limestone is 1 to 3 m thick. Algal nodules and brachiopods such as Latiproductus cf. latissimus are fairly common in the limestone. The siltstones and mudstones above are commonly calcareous and shelly with some nodules of limestone or ironstone. The overlying sandy Birchlaw Limestone is followed by a cyclical succession including the Cokeyard Coal, Tibbie Pagan's Limestone, Orchard Limestones and the Blue Tour (Calmy) Limestone.

The Passage Formation (PGP), has pebbly sandstone immediately above the unconformity with the Upper Limestone Formation in the Muirkirk area, but in places (e.g. Proscribe Burn [NS 6724 2517]), the lowest part of the formation includes a marine band containing calcareous brachiopods (Davies, 1972). Farther south in this burn, a faulted section contains three thin bioclastic limestone beds intercalated with fine to medium-grained sandstones, siltstones and thin coals. In the Lochside Borehole (1980) [NS 6044 1502], the formation includes six limestones, the thickest of which is 1.3 m. The faunas include Lingula sp., productids, gastropods and crinoid fragments.

The base of the Lower Coal Measures (LCMS) is defined at the Lowstone Marine Band or its equivalent. In the Sanquhar Basin, the base of the Lower Coal Measures is taken at the locally developed Tait's Marine Band (Davies, 1970). The stratigraphy of the formation is based mainly on borehole information (Figure 9). The coal seams can be correlated with those around Cumnock (Eyles et al., 1930). In the Muirkirk–Cronberry area most of the formation has been downthrown to the south-east of the Bankend Fault, although near Airds Moss, part lies north-west of the fault. The Lower Coal Measures in New Cumnock area lie in a faulted syncline at the south-east end of the Ayrshire Coalfield (Simpson and MacGregor, 1932).

The base of the Middle Coal Measures (MCMS) is taken at the base of the Queenslie (Vanderbeckei) Marine Band (Figure 9). This contains Lingula and foraminifera. Coal seams occur mostly in the lower part of the formation around Muirkirk, but seams are better developed in the New Cumnock area.

The base of the Upper Coal Measures (UCMS) lies at the base of Skipsey's (Aegira­num) Marine Band (Figure 9). In the small outcrop around Muirkirk, the formation includes reddened medium to coarse-grained sandstones. In the Sanquhar Basin around Kirkconnel the Skipsey's Marine Band is either a distinctive dark grey/black carbonaceous siltstone, or locally an impure limestone, up to 0.25 m thick, containing a benthic fauna (Davies, 1970). Around Sanquhar, grey mudstones above the marine band contain Planolites ophthalmoides and this facies represents the final retreat stage of the marine incursion. Reddening of the rocks throughout the district could be an original feature (Simpson and Richey, 1936) but, as Permian lavas lie unconformably on the measures, some reddening could be due to a former Permian red-bed cover.

Permian

The Lower Permian Carron Basalt Formation (CnB) rests unconformably on Middle Coal Measures north-east of Sanquhar, where it is best exposed [NS 787 103]. The small inclined outcrop comprises weathered, vesicular and amygdaloidal, subaerially erupted olivine-basalt lavas, altogether 35 to 45 m thick.

Intrusive igneous rocks

Details of the numerous igneous intrusions in the district are given in (Figure 10). The Ordovician intrusions are closely associated with volcanic rocks of the Crawford and Bail Hill Volcanic groups. The steeply inclined sheets of dolerite (D_MCHB) occur near Rough Naze [NS 710 042] and Polshill [NS 650 128]; [NS 646 127]. Vent breccia (xW_v^H/M) occurs south of Bail Hill [NS 758 134], two trachyandesite sills (Ns) occur nearby [NS 7587 1321]; [NS 7583 1310] (Eyles, 1948; McMurtry,1980b; Phillips and Smith, 1996). The dykes of altered felsic rock (J) trend north–east to east–north–east, near the Bail Hill Volcanic complex e.g. [NS 762 135] and [NS 768 137].

The Early Devonian granodiorite and diorite intrusions (G^D) form a number relatively large plutons, and include the north-east tip of the Cairnsmore of Carsphairn granodiorite [NS 595 002]. The Spango granodioritic pluton [NS 78 18] is a medium-grained hornblende-biotite-granodiorite or quartz-diorite (Walker, 1928). The margins are melanocratic due to a higher proportion of biotite and hornblende. Pyroxene-biotite diorite and microdioritic bodies (H), for example at Windy Standard [NS 620 017] and Cannock Hill [NS 636 042] appear to be early mafic phases of the magmatism. Stephens and Halliday (1984) analysed several of the complexes and found that they were part of the south of Scotland calc-alkaline suite. Hornfelsed sedimentary rocks occur in the aureoles of the granodiorite-diorite complexes, and biotite is the most common metamorphic mineral.

Minor Early Devonian microdioritic intrusions (P), for example at Knockenshag [NS 755 180], lie close to the Spango Granodiorite and contain pink quartzo-feldspathic and pegmatitic veinlets suggesting that the main granodioritic intrusion was a later phase. Dykes of pyroxene and/or plagioclase-phyric microdiorite (PD) are intruded into the Ordovician rocks in the south of the district. Some contain biotite, for example in the Euchan Water [NS 705 063]. Many of the dykes have an east–north–east to north–east trend, which is roughly parallel to the regional strike of the Ordovician rocks and the elongation of the Spango pluton. The lamprophyric dykes (L), for example in the Kiln Burn [NS 767 144] and the Glenwharrie Burn [NS 715 518], are up to 5 m thick and trend north–north–east.

Most of the Early Devonian intrusions associated to the Lanark Group occur as dykes and sills within the Duneaton Volcanic Formation. A minor intrusive tuff dyke (X), [NS 767 231] also cuts this formation. Relatively thick sheets of microgranodiorite (hF^Gd), near Scar Hill [NS 744 225], contain aligned hornblende phenocrysts, whereas others are biotite bearing (bF^Gd). The quartz dolerite sills (qD) of Early Permian age are locally up to 100 m thick, for example near Cairnscadden Hill [NS 612 168], and in places are intruded by teschenite sills (DTe, alkali olivine-dolerite with analcime). Part of the classic differentiated Lugar Sill (Henderson and Gibb, 1987) crops out on the western margin of the district [NS 601 215]. It is 49 m thick with a central unit of ultramafic theralite-picrite (U) intruded into earlier sheets of teschenite. Other intrusions include the Early Permian olivine-basalt (oB) and olivine-monchiquite (L^Mo) dykes, south of the Kiln Burn [NS 774 130] and north-west of Sanquhar e.g. [NS 7755 1125] are north–west–trending. Simpson and Richey (1936) reported that one of these dykes, encountered during mining near Sanquhar, contains abundant inclusions of altered peridotite up to 50 mm in length. Camptonite dykes (LC), containing amphibole and usually some analcime, are exposed in the Kello Water [NS 732 101]. The vent breccias (Z^B_v), which crop out within the Sanquhar Basin, are related to the Lower Permian alkaline volcanic rocks. The vents are filled with predominantly angular pieces of olivine basalt and a few fragments of Carboniferous sedimentary rock. Small vents, e.g. south of Crawick [NS 774 107] and east of Sanquhar church [NS 783 102], are up to 100 m along their long axes and have a weak north-west trend. The vent north-east of Muirkirk [NS 704 284] contains basaltic fragments, whereas the vent breccia beside the River Ayr [NS 615 265] includes mainly sedimentary rock fragments.

A number of basalt (B^T) and dolerite (D^T) dykes of Palaeogene age occur within the district, and were intruded about 52 million years ago. A feldspar-phyric tholeiitic dolerite dyke (fD^T), up to 6 m thick e.g. [NS 702 152], is intruded along the Carboniferous and post Carboniferous faults on the northern side of the Sanquhar Basin. The north–west-trending Armathwaite–Cleveland basaltic andesite dyke (A^B) is exposed on the east side of Gallow Rig [NS 615 029]. Quartz-bearing dolerite dykes (qD^T) usually trend west–north–west, for example in the Kello Water [NS 688 090]. Analcime-bearing dolerites (aD^A) are a minor component of this dyke swarm.

Intrusions of uncertain age, but probably mostly of either Early Permian or Palaeogene age, include altered dykes (K) encountered in mine workings and at outcrop. A dolerite dyke crops out in Crawick Water [NS 785 123]. Olivine-bearing and xenolithic basalt dykes occur near Glenmuirshaw [NS 698 204] (Smith, 1996a). The large intrusive body near Meath Hill [NS 615 282], associated with a vent breccia, is probably Early Devonian in age.

Regional structure and metamorphism

In the New Cumnock district, the Midland Valley graben and the Southern Uplands massif display different Lower Palaeozoic structures. The intervening Southern Upland Fault (Figure 2) has had a long history of movement starting in Lower Palaeozoic times, with later activity mainly during Devonian and post-Westphalian orogenic episodes (Floyd, 1994; Smith, 1995c).

Early Palaeozoic (pre-Acadian) Deformation has affected the Ordovician rocks of the Southern Uplands (Floyd, 1982) which were deposited in either a back-arc basin (Stone et al., 1987) or fore-arc trench (McKerrow et al., 1977; Hepworth et al., 1982) on the southern edge of the Laurentian continent. Major north–east-trending steep reverse faults or rotated thrusts divide this succession into parallel tracts; younger strata occur to the south-east despite each tract younging internally to the north-west. These faults appear to have formed as the basin closed, probably during the Silurian. Within the tracts, there are some tightly folded zones, and others which are near vertical with a younging direction mainly to the north-west. F1 folds have axial planes roughly parallel to strike, but a slaty cleavage is developed only locally in mudstone interbeds. In many cases, fold pairs are found with the anticline to the north of the syncline, indicating an overall vergence to the south-east.

Within the Midland Valley, the Llandovery–Wenlock strata appear to have accumulated in transtensional strike-slip basins and are paraconformable or disconformable with the overlying Siluro–Devonian Lanark Group. Post-Wenlock to pre-Siluro–Devonian sinistral transpression noted elsewhere within the Midland Valley (Smith, 1995c) appears not to have affected the Llandovery–Wenlock rocks of this area, because they lay in releasing bends of precursors of the Kennox and Bankend faults. The Bankend Fault (part of the Kerse Loch system) separates the Lesmahagow and Hagshaw Hills inliers (Figure 2).

Regional metamorphism has affected the Lower Palaeozoic rocks. It has produced mineral assemblages indicative of the prehnite-pumpellyite facies in spilitic lavas from the Leadhills Imbricate Zone (Hepworth et al., 1982). The volcanic rocks around Bail Hill also contain zeolites, which may have formed either soon after the extrusion of the rocks or during later burial metamorphism. The volcaniclastic rocks of the Stoodfold Member (Kirkholm Formation) contain small patches of kaolinite, and Hepworth et al. (1982) concluded that the fault block containing the Bail Hill complex was metamorphosed to a lower grade than the blocks in the Leadhills Imbricate Zone. Illite crystallinity studies (Merriman and Kemp, 1998) indicate that diagenetic to anchizone metamorphism is common in the Ordovician mudstones and later epizone metamorphism occurred in aureoles around the Devonian intrusions.

Middle Devonian (Acadian) deformation (Soper et al., 1992) is marked by the unconformity between the Lanark and Inverclyde groups. The deformation is heterogeneous, probably because of the influence of pre-existing faults and sinistral transpression. Near the Southern Upland Fault the Lanark Group is folded in open, upright structures with east–north–east-trending axes oblique to the Southern Uplands Fault. At this time this fault also had a large component of down-throw to the north-west and a thick Lanark Group succession is preserved in the narrow graben between the Southern Upland Fault and the Kennox Fault (Figure 2). West of the Hagshaw Hills, there is only a moderate angular unconformity between the Lanark Group and the Inverclyde Group. This lower degree of deformation may relate to release in the sinistral strike-slip regime north-west of the Bankend Fault.

Carboniferous deformation is indicated by local unconformities and syndepositional movement on faults, particularly those having Caledonoid trends. The unconformity between the Inverclyde and Strathclyde groups is due to uplift within the Midland Valley, associated with the magmatic updoming prior to the eruption of the Clyde Plateau lavas (Forsyth et al., 1996). The resultant alkali basalts are typical of intra-plate rift systems (Smedley, 1986). The unconformity below the Passage Formation may be related to tilting of blocks between pre-existing Caledonoid faults due to dextral strike slip, but local channelling within the formation may be due to either eustatic, volcanic or sedimentary processes (Read, 1989).

Post-Carboniferous deformation is indicated by folding and faulting of the Westphalian strata. The north-east-trending, open, upright Muirkirk syncline (Figure 2) has an axial trace offset by the later north–west-trending faults. On the south-east side of the Crook Brae Fault (Smith, 1996b) is a tight north–east-trending syncline (Figure 2) with an interlimb angle of about 45Þ, which may have developed at the same time as the Crook Brae Fault.

The Carmacoup and Kennox fault zones, along with the Bankend Fault to the north-west of Muirkirk (Figure 2), have Caledonoid trends, probably inherited, which are slightly oblique to the Southern Upland Fault. The effective throw on the Bankend Fault is 60 to 600 m, down to the south-east (Davies, 1972). The Kennox Fault and the Southern Upland Fault had effective downthrows to the north-west in post-Westphalian times. Occurrences of near horizontal slickensides on the north–east-trending faults indicate that there was also a component of strike-slip. The Gass Water Fault downthrows to the south-west, but near horizontal slickensides indicate that there was some strike-slip displacement. The Glenmuir-Carmacoup Fault (Figure 2) is locally offset by an east–south–east-trending dextral strike-slip fault. South of the Glenmuir Water [NS 682 192], the Glenmuir Fault is associated with dextral shearing on near vertical, north–east-trending fractures. Similar dextral movements have been postulated elsewhere in the Midland Valley starting from Namurian times (Read, 1988). Some dextral shearing occurred on the Southern Upland Fault (Smith, 1995c) but this probably produced less than 10 km displacement (Stedman, 1988).

In the Southern Uplands, several major wrench faults trending north–north–west to north–west offset the tract-bounding faults; one of the largest lies along Glen Afton (Figure 2). These faults tend to be near vertical and locally offset dykes of Early Devonian age. The faults may have been initiated in the Devonian but were reactivated in Carboniferous times.

The Permian and Carboniferous rocks of the Sanquhar Basin lie in a half-graben bounded to the north-west by a splay of the Southern Upland Fault zone which allowed local downthrow to the south-east from Carboniferous times (Figure 2). The strata within the outlier lie in an open syncline trending and plunging gently north-east (Davies,1970). The Sanquhar Fault, a normal fault bounding the half-graben to the north-east, splits into several branches which generally downthrow to the south-west. Since Lower Coal Measures occur to the east of the fault, the development of the Sanquhar Fault (Figure 2) is considered to postdate initial deposition in the basin and continued its activity after the intrusion of the Lower Permian sills. The overall downthrow on the fault has been calculated at 580 m to the south-west (Davies, 1970).

During Mesozoic and Palaeogene times the entire region appears to have had positive relief. The intrusion of the Palaeogene dykes may follow tensional fractures related to initiation of seafloor spreading in North-east Atlantic.

Concealed geology

The results of regional gravity and aeromagnetic surveys are given as contoured insets on the 1:50 000 Series Sheet 15W New Cumnock. Only a very brief description of the main geophysical features and their relevance to the concealed geology is provided here. More details are given by Kimbell (in Smith, 1999), including discussion of detailed ground and airborne geophysical surveys (Dawson et al., 1977; Rollin, 1987).

The highest Bouger gravity anomaly values occur in the north-west corner of the district and are part of a positive gravity feature related to the adjacent Distinkhorn granodiorite/diorite complex. Elsewhere, the gravity anomaly pattern over the Midland Valley broadly reflects variation in the thickness of low-density Upper Palaeozoic sedimentary rocks above the Lower Palaeozoic basement. There is a residual low over the Sanquhar Basin, which is due to the density contrast between the Carboniferous rocks within the basin and the underlying Lower Palaeozoic basement. Simple modelling suggests that the observed effect could be explained by a basin with a total thickness of up to 500 m. A modest negative gravity effect occurs over the Spango pluton.

The rise in magnetic field values towards the north-west corner of the district is due to the influence of the Distinkhorn Complex. On regional magnetic images, the southern edge of the anomaly associated with the complex appears to lie on an east-trending magnetic lineament. Nearby there are local magnetic anomalies over early Permian vents, for example near Alder Burn [NS 615 265] and Meath Hill [NS 603 285]. A belt of magnetic anomalies crosses the central part of the district in a south-west–north-east direction. This is due to a variety of sources in the vicinity of the Southern Upland Fault, including: the Duneaton Volcanic Formation in the Midland Valley; the Marchburn Formation in the northern part of the Southern Upland Terrane (Floyd and Trench, 1989); Ordovician igneous rocks near Polshill [NS 650 130] (Rollin, 1978) and in the Bail Hill complex; the Early Devonian Hare Hill and Spango intrusions; possibly a concealed ophiolitic body analogous to the Ballantrae Complex (Floyd, 1999).

Quaternary

About 75% of the district is covered by Quaternary deposits (drift) of Pleistocene (Devensian) and Holocene (Flandrian) age. The nature of these deposits is shown in (Figure 11). Artificial (man-made) deposits locally cover the drift deposits and bedrock, and are the product of human modification of the natural environment, notably in areas of industrial development. The man-made deposits shown on the map represent those identifiable at the time of survey. They were identified by field recognition and by the examination of documentary sources such as topographical maps, aerial photographs and site investigation data. Only artificial deposits known to be in excess of 1.5 m thick are shown.

Most Quaternary deposits and landforms probably date from the last major glaciation of the Devensian Stage, which occurred during the Dimlington Stadial (28 000 to 13 000 years BP). At its maximum, ice converging from the Southern Uplands and the Firth of Clyde covered the entire district. In the area north of the Nith, the prominent hills and ridges are generally drift free and have been glacially eroded. The main movement of ice was to the east or south-east. North–east-trending fault lines were locally exploited, and glacially carved valleys, such as that along the Kennox Fault, were created. In the Southern Uplands glens, particularly Glen Afton, roches mouto­nées and associated striae indicate a northerly to north-westerly ice flow. A buried channel lies below the floodplain of the River Nith and was cut prior to the Dimlington Stadial. A buried channel below New Cumnock is mainly filled with clay and sand deposits at least 56 m thick. The marked change in depth of the buried channel of the Nith across the Southern Upland Fault was attributed to post-Cretaceous to pre-Flandrian fault movement (Lumsden and Davies, 1965) or possibly ice-gouging of the softer rocks.

Pleistocene (Devensian) deposits are dominated by till, the greatest thickness of which is in valleys such as that of the Garpel Water [NS 705 238]. In the Guelt Water [NS 664 172] and at Greenock Mains [NS 635 277] (Plate 3), an intercalation of irregularly stratified sand and gravel separates two tills (Smith,1898; Gordon, 1993). The dark brown lower till was a product of ice moving inland from the west, as indicated by the presence of boulders of Permian sandstone derived from the Mauchline basin (Bailey, 1930). It contains many other clasts derived from areas to the west, and which were probably transported by Highland ice moving along the Firth of Clyde (Holden, 1977). The upper till is up to 10 m thick, reddish brown and sandy with greywacke and Carboniferous sandstone pebbles. This till appears to be more locally derived, and was deposited by ice from the Southern Uplands. In the Sanquhar Basin, the till contains kylite boulders (Simpson and Richey, 1936) derived from intrusions between Dalmellington and Ochiltree in Ayrshire, confirming east-south-east transport by the ice. Within the Southern Uplands, till deposits are limited to the main valleys, many of which are north–south aligned, and were exploited by ice moving northwards.

Glaciofluvial sand and gravel is mainly glacial outwash and forms mounds and ridges commonly on the flanks of the larger valleys, such as the rivers Ayr, Nith and Bellow Water. Esker ridges occur locally, for example near Muirkirk [NS 690 266]. About 3 m of stiff, bluish grey, laminated clay near Cronberry [603 226] was probably deposited in a small proglacial or ice-dammed lake. Late-glacial meltwater channels commonly occur along the flanks of the valleys such as that of the Nith (around Kirkconne and Sanquhar) and they were associated with the deposition of the outwash sand and gravel. Hummocky glacial deposits are preserved in Southern Uplands glens, for example alongside Holm Burn [NS 636 003], and the upper reaches of the Euchan Water. These deposits probably accumulated from small glaciers during the Loch Lomond Stadial (11 000 to 10 000 years BP). However, the deposits to the south-west of New Cumnock [NS 602 127] and near the head of the Duneaton Water [NS 732 232], Bain's Burn [NS 766 211] and the Glenmuir Water [NS 687 196] formed earlier during ice sheet deglaciation.

Flandrian deposits accumulated during the warmer, wetter climate that began about 10 000 years BP at the beginning of the Holocene. Since then the modern drainage pattern developed. Alluvium is well developed along the larger rivers such as the Nith and the Ayr. Along the Crawick Water, the floodplain is up to 150 m wide. Alluvial terraces of sand and gravel are present along the Nith, mainly on the northern side. Locally, for example south of the Spango Water [NS 788 185], terraces are partly covered in peat. Alluvial fans occur, for example on the north side of the Nith valley [NS 760 115]. In smaller fans, such as the one north of the Spango Water [NS 762 181], the deposits have been quarried. Peat has been mapped where deposits are 1 m or more thick. Peat up to 5 m thick was proved in boreholes north of New Cumnock. On broad gentle slopes on both sides of the Ayr and Nith valleys, for example Airds Moss and Burnfoot Moss, raised mosses are up to 6 m thick. Blanket peat deposits in the Southern Uplands are generally thinner. Landslips have occurred locally where river meanders have cut into banks of oversteepened till, for example north of the Glenmuir Water [NS 679 195].

Chapter 3 Applied geology

The New Cumnock district has a long history of mineral extraction and industrial development, and although this activity has declined from its peak in the early part of this century its legacy affects the continued urbanisation and development of the area. Consideration is needed to ensure that continued urban development does not inadvertently sterilise natural resources.

Mineral resources

Peat mosses tend to occur in the more remote, upland parts of the district and are therefore unlikely to be of commercial interest. The Scottish Peat Committee has investigated Airds Moss, which lies north of Cronberry, as a resource for fuel. This raised peat moss is composed primarily of Sphagnum and it was estimated that peat between 0.5 to 8 m thick covered some 1066 hectares. The volume was estimated as 28.4 million cubic metres, which made the moss one of the twelve most important peat resources in Scotland. It may be considered for horticultural and agricultural use as well as for producing charcoal.

There are no significant resources of sand and gravel in the district according to Merritt and Gallagher (1989). The sand and gravel deposits tend to be thin, patchy and in environmentally sensitive areas. Some sand and gravel deposits overlie potential opencast coal sites and the sand and gravel overburden may be worked separately.

Building stone was worked locally for dry stone walls, usually from dolerites, Carboniferous sandstones or Lower Palaeozoic greywacke sandstones. Sandstone (freestone) was formerly quarried around Muirkirk and Sanquhar e.g. [NS 768 123]; [NS 781 106] for local buildings.

Large resources of stone are available for crushed rock aggregate in the area, but at present there is no commercial quarrying mainly due to remoteness from the larger markets. Sandstone, for example, should be available for fill from the opencast operations. The dolerites, granites and felsites of the district have been utilised locally.

Bings of colliery waste have potential for use as bulk fill or the recovery of their coal content. Some of the tips have been landscaped and much of the material has been removed.

Limestone, mainly from the Clackmannan Group (particularly the Hawthorn Limestone) and the base of the Inverclyde Group (e.g. Craigdullyeart) has been exploited in the past for agricultural lime and as a flux in blast furnaces. None of these sources are presently worked or likely to be economic for any large demand. At Craigdullyeart [NS 663 153], besides being quarried, the limestone was mined by pillar and stall methods (Smith, 1996b). Craigdullyeart limestone samples contain 10.7% SiO2 (Muir et al., 1956) but material of higher grade could be obtained (Robertson et al., 1949). In the Penbreck, New Cumnock and Muirkirk areas, limestones in the Upper Limestone Formation were quarried, for example Blue Tour Limestone [NS 621 163]. The McDonald Limestone was quarried around Muirkirk [NS 70 26]. Several formerly important coalfields were active in the Muirkirk, New Cumnock and Sanquhar areas. The Coal Measures and the Limestone Coal Formation were the main targets. Geological details are given in Eyles et al. (1930), Simpson and MacGregor (1932), Simpson and Richey (1936) and Davies (1970, 1972). All deep mining has ceased, and is likely to remain uneconomic. Opencast workings have largely been completed and restored in the Kirkconnel-Sanquhar area (Smith, 1995b) and south-west of New Cumnock. Coaling is being/has been investigated in the areas north-east of New Cumnock, north and west of Muirkirk, around Penbreck and along the Kennox Water. In the Glenmuir area small pits worked the McDonald Coal. The suitability of bituminous shales for hydrocarbons and gas prospects is unknown.

Ironstone in thin beds, such as the Lugar Blackband and the Knockshinnoch Blackband ironstones (both Lower Coal Measures), were worked in the 19th century within the Muirkirk–Cronberry and New Cumnock areas respectively. Clayband ironstones near Muirkirk were also worked. For all practical purposes, these resources are exhausted.

Mudstones associated with the McDonald Limestone were formerly used to make the bricks for the Muirkirk Ironworks (Geikie et al., 1871). Reddish mudstones in the Upper Carboniferous strata at Sanquhar were also used locally as brick clays and for terracotta (Simpson and Richey, 1936). Late-glacial or alluvial laminated clay at Cronberry was used in a former brick and tile works (Geikie et al., 1871).

A narrow quartz vein carrying coarse stibnite, previously worked on a very small scale for antimony (Dewey, 1920), cuts the Devonian Hare Hill Granodiorite at The Knipe. Boast et al. (1990) have shown that the granodiorite is host to zoned As–Sb– Cu–Pb–Zn mineralisation carrying significant concentrations of Au. The gold is closely associated with arsenopyrite within zones of sericitised granodiorite, the highest grades (> 1 ppm) occurring adjacent to late-stage, north–south Sb–Pb veins.

The intersections of major fractures such as the Southern Upland Fault and the Leadhills Fault with north and north–north–west-trending fractures offer potential sites for further metalliferous mineralisation in the district. Lead was reportedly mined (Wilson, 1921) or trialled (Geikie et al., 1871) on the west side of the Afton Water, 4 km south of New Cumnock, close to the trace of the Southern Upland Fault. There is a historical record of production from a lead vein in a limestone quarry near Old Cumnock (Wilson, 1921). A radioactive anomaly resulting from uranium minerals was found in the stream sediments associated with the Bail Hill Volcanic Group. Several baryte veins were recorded in the area in the 19th century (Geikie et al.,1871). Early accounts of the mines and outcropping veins are given by MacGregor (1944) and Hobson (1959). Before its closure in the 1960s, Gasswater Mine [NS 655 219] was the largest single producer of barytes in the UK (Dunham et al., 1979), yielding over 500 000 tons. Scott (1967) described the deposit, which occurs in veins with a north–west trend. Merritt and Gallagher (1989) concluded that this prospect is exhausted from the point of view of a mining company, but they recorded other small veins. The age of the baryte mineralisation is at least post-Westphalian since it occurs in faults affecting Westphalian rocks, and Scott (1967) concluded from geochemical evidence that all the baryte veins belonged to one phase of deposition which was likely to be pre-Palaeogene in age.

The water supply in the district comes mostly from surface sources. The groundwater supplies are unknown due to the lack of hydrogeological records from boreholes. Swallow holes and springs on the edge of the Kinnesswood Formation indicate some groundwater potential. Permeable sandstones in the Clackmannan Group and Coal Measures may also be aquifers.

Environmental geology

A summary of the key environmental issues within the New Cumnock district is given in (Figure 12).

Near mineshafts, considerable areas have been covered with made ground (mainly colliery tips), for example near Gateside [NS 764 114]; [NS 766 116]. The removal of tips for bulk fill and their coal content can be beneficial. Most opencast sites in the area have been worked and infilled, for example Libry Moor [NS 720 115]. Some small pits and quarries, for example the former clay pits south-east of Crawick [NS 781 106], are locally backfilled with refuse. The opencast pit near Edge Hill [NS 643 171] has not been restored, nor have pits north of Sanquhar [NS 783 104]. Disturbed ground is mapped where areas of mining and backfilling are complex and have not been delineated by plans.

Information sources

Further geological information held by the British Geological Survey relevant to the New Cumnock district is listed below. It includes published material in the form of maps, memoirs and reports and unpublished maps and reports. Also included are other sources of data held by BGS in a number of collections, including borehole records, mine plans, fossils, rock samples, thin sections, hydrogeological data and photographs. Searches of indexes to some of the collections can be made on the Geoscience Index System in BGS libraries. This is a developing computer-based system, which carries out searches of indexes to collections and digital databases for specified geographical areas. It is based on a geographical information system linked to a relational database management system. Results of the searches are displayed on maps on the screen. At the present time (1999) the datasets are limited and not all are complete. The available indexes are listed below:

• Index of boreholes
• Topographical backdrop based on 1:250 000 scale maps
• Outlines of BGS maps at 1:50 000 and 1:10 000 scale and 1:10 560 scale County Series
• Chronostratigraphical boundaries and areas from BGS 1:250 000 maps
• Geochemical sample locations on land
• Aeromagnetic and gravity data recording stations
• Land survey records

Details of geological information available from the British Geological Survey can be accessed on the BGS Web Home Page at http://www.bgs.ac.uk.

Maps

• 1:625 000
• United Kingdom (North Sheet), Solid geology, 1979; Quaternary geology, 1977
• 1:250 000
• Sheet 55N 04W Borders , Solid geology, 1986
• Sheet 55N 06W Clyde , Solid geology, 1985
• 1:63 360
• Sheet 22 Kilmarnock Solid & Drift 1928
• 1:50 000
• Sheet 8E Loch Doon, Solid 1994; Drift 1980
• Sheet 9W New Galloway, Solid 1978; Drift 1979
• Sheet 9E Thornhill, Solid 1996; Drift 1980 Sheet 14E Cumnock, Solid 1976; Drift 1980
• Sheet 15W New Cumnock, Solid 1986; Drift 1982
• Sheet 15E Leadhills Solid 1987. Drift 1981
• Sheet 22E Kilmarnock, in press.
• Sheet 23 Hamilton, Solid 1995; Drift 1993
• The New Cumnock district is the western half of the area which was formerly covered by Sheet 15 (Sanquhar) of the Geological Map of Scotland.
• 1:10 000 and 1:10 560
• Details of the original geological surveys are listed on editions of the 1:63 360 and 1:50 000 geological sheets. Copies of the fairdrawn maps of these earlier surveys may be consulted at the BGS Library, Edinburgh.
• The maps at six-inch or 1:10 000 scale covering the 1:50 000 Series Sheet 15W New Cumnock are listed below, together with the surveyors' initials and the dates of the survey. The surveyors were H F Barron, I B Cameron, J D Floyd, M J Gallagher, G I Lumsden, E A Pickett and R A Smith. The maps are not published, but are available for consultation in the Library, BGS Edinburgh, and also at BGS Keyworth and the BGS London Information Office, in the Natural History Museum, South Kensington, London. Dyeline copies may be purchased from the Sales Desk.

• Geophysical maps
• 1:500 000 000
• Colour shaded relief gravity anomaly map of Britain Ireland and adjacent areas, 1997.
• Colour shaded relief magnetic anomaly map of Britain Ireland and adjacent areas, 1998
• 1:250 000
• 55N 04W Borders, Aeromagnetic anomaly, 1980
• 55N 04W Borders, Bouguer gravity anomaly, 1981
• 55N 06W Clyde, Aeromagnetic anomaly, 1980
• 55N 06W Clyde, Bouguer gravity anomaly, 1985
• 1:50 000
• Geophysical information maps; these are plot-on-demand maps which summarise graphically the publicly available geophysical information held for the sheet in the BGS databases. Features include:
• Regional gravity data: Bouguer anomaly contours and location of observations.
• Regional aeromagnetic data: total field anomaly contours and location of digitised data points along flight lines.
• Gravity and magnetic fields plotted on the same base map at 1:50 000 scale to show correlation between anomalies.
• Separate colour contour plots of gravity and magnetic fields at 1:125 000 scale for easy visualisation of important anomalies.
• Location of local geophysical surveys.
• Location of public domain seismic reflection and refraction surveys.
• Location of deep boreholes and those with geophysical logs.
• Geochemical atlases
• 1:250 000
• Southern Scotland and part of Northern England, 1993.
• Point-source geochemical data processed to generate a smooth continuous surface presented as an atlas of small-scale colour-classified digital maps. Geochemical Survey Programme data are also available in other forms including hard copy and digital data.
• Hydrogeological maps
• 1:625 000
• Sheet 18 (Scotland) 1988.
• Groundwater vulnerability (Scotland), 1995.

Publications

The various books, memoirs, reports and papers relevant to the New Cumnock district are listed in the reference section. British Geological Survey Technical Reports and other special reports are not widely available but may be purchased from the British Geological Survey or consulted at the British Geological Survey and other libraries.

The district lies within the South of Scotland and Midland Valley areas of the British Regional Geology series of publications (Greig, 1971; Cameron and Stephenson, 1985), which are readily available in British Geological Survey and some other bookshops. Other aspects of the geology within and adjacent to the district can be found in British Geological Survey Memoirs (Geikie, 1871; Richey et al., 1930; Eyles et al., 1949; Paterson et al., 1998; Floyd, 1999; Floyd and MacMillan, in press), Technical Reports (Smith, 1993; 1994; 1995a–c; 1996a–b; 1997), Bulletins (Davies, 1970; 1972; Lumsden, 1964; 1965; 1967a–b) and special reports (Browne, 1980; Paterson, et al., 1986). Petrological and geochemical details appear in various British Geological Survey Miner­alogy and Petrology Technical Reports (Phillips, 1993; 1994a–b; 1995; 1998; Phillips and Smith, 1995; Merriman and Kemp, 1998). For details of a collection of internal biostratigraphical reports contact the Manager, Basin Analysis and Stratigraphy Group, BGS Keyworth.

Economic information on coal, ironstone and limestone can be found in British Geo­logical Survey Economic Geology Memoirs (MacGregor and Wilson, 1920; Eyles et al., 1930; Simpson and MacGregor, 1932; Simpson and Richey, 1932; Robertson, et al., 1949). Information on bulk minerals is located in Reports of the Institute of Geological Sciences (Cameron, 1977) and various open file reports of the British Geological Survey (1984–1986). That of metalliferous minerals occurs in wartime pamplets (MacGregor, 1944), special reports (Muir et al., 1956; Robertson et al., 1949) and Mineral Reconnaisance/ Technical Reports (Merritt and Gallagher, 1989). Records of water wells in the district were published in Water Supply Papers for 1:50 000 Series geological sheets 7 to 18 inclusive (1968). General hydrogeological information can be found in Robins (1990). Geophysical information appears in Technical Reports (Kimbell, in preparation). The geothermal potential of the district is briefly assessed by Holliday (1985).

Documentary collections

BGS holds collections of records of boreholes, which can be consulted at BGS, Edinburgh, where copies of most records may be purchased. For the New Cumnock district the collection consists of the sites and logs of about 1450 boreholes. Borehole index information, which includes site references, has been digitised. The logs are either handwritten or typed and many of the older records are driller's logs.

There is a collection of site exploration reports that describe foundation investigations on individual sites prior to construction. There is a digital index and the reports themselves are held on microfiche. For the New Cumnock district there are presently (1999) about 25 reports.

BGS maintains a collection of mine plans of underground workings for minerals other than coal and oilshale. Plans held which fall within the district include the working for fireclay (1), brickclay (6), limestone (6), antimony (2), ironstone (clayband, 2, blackband, 34) and barytes (11). Records of water boreholes, geochemical data including analyses of stream-sediment, gravity and magnetic data, and seismic data, are held at BGS, Edinburgh.

Material collections

About 100 Geological Survey photographs illustrating aspects of the geology of the New Cumnock district are deposited for reference in BGS libraries (Edinburgh, and Keyworth), and the Information Office (London). The photographs were taken at various times from 1937 to 1996. The photographs depict details of various rocks and sediments exposed either naturally or in excavations, along with some general views. A list of titles can be supplied on request. The photographs can be supplied as black and white or colour prints and 35 mm colour transparencies, at a fixed tariff, from the Photographic Department, BGS, Edinburgh. There is a petrological collection for the New Cumnock district consisting of over 800 hand specimens and thin sections. Most samples and thin sections are of the igneous rocks in the district. The sedimentary rocks are poorly represented. Information on databases of rock samples, thin sections and geochemical analyses can be obtained from the Group Manager, Mineralogy and Petrology Section, BGS, Edinburgh.

There is a bore core collection, taken from cored boreholes, for the district, which at present (1999) consists of over 153 samples (hand specimens) from more than 14 bores which are registered in the borehole collection.

There is an extensive palaeontological collection taken from surface and temporary exposures, and from boreholes, throughout the New Cumnock district. The collection is a working collection and is used for reference. The collection consists of 12 938 macrofossils held at BGS, Edinburgh (Ordovician, 324; Silurian, 297; Siluro–Devonian, 11; Dinantian, 3523; Namurian, 3912; Westphalian, 4848; Quaternary, 23). A list of fossil samples from the New Cumnock district can be obtained from the Curator, Scotland and Northern England, BGS, Edinburgh.

Other relevant collections

Coal abandonment plans are held by the Coal Authority, Mining Records Department, Bretby Business Park, Ashby Road, Burton-on-Trent, Staffs, DE15 0QD. Sites of Special Scientific Interest are the responsibility of Scottish Natural Heritage, Battleby Redgorton, Perth, PH1 3EW.

References

Most of the references listed below are held in the Library of the British Geological Survey at Keyworth, Nottingham. Copies of the references can be purchased subject to the current copyright legislation.

Armstrong, H A, Owen, A W, Scrutton, C T, Clarkson, A N K, and Taylor, C M. 1996. Evolution of the Northern Belt, Southern Uplands: implications for the Southern Uplands controversy. Journal of the Geological Society of London, Vol. 153, 197–205.

Bailey, E B. 1930. Ayrshire, Renfrewshire and Dumbartonshire. 72 in Summary of Progress of the Geological Survey of Great Britain for 1929. (London: H MS O.)

Bluck, B J. 1978. Sedimentation in a late orogenic basin: the Old Red Sandstone of the Midland Valley of Scotland. 249–278 in Crustal evolution in northwestern Britain and adjacent regions. Bowes, D R, and Leake, B E (editors). Special Issue of the Geological Journal, No. 10.

Boast, A M, Harris, M, and Steffe, D. 1990. Intrusive-hosted gold mineralization at Hare Hill, Southern Uplands, Scotland. Transactions of the Institution of Mining and Metallurgy (Section B: Applied Earth Science), Vol. 99, 106–112.

Browne, M A E. 1980. The Upper Devonian and Lower Carboniferous (Dinantian) of the Firth of Tay, Scotland. Institute of Geological Sciences Report, No 80/9.

Burgess, I C. 1961. The fossil soils of the Upper Old Red Sandstone of South Ayrshire. Transactions of the Geological Society of Glasgow, Vol. 24, 138–153.

Cameron, I B. 1977. Sand and gravel resources of the Dumfries and Galloway region of Scotland. Institute of Geological Sciences Report, No. 77/22.

Cameron, I B, and Stephenson, D. 1985. British regional geology: the Midland Valley of Scotland. (3rd edition). (London: H MS O for British Geological Survey.)

Davies, A. 1970. Carboniferous rocks of the Sanquhar Outlier. Bulletin of the Geological Survey of Great Britain, No. 31, 37–87.

Davies, A. 1972. Carboniferous rocks of the Muirkirk, Gass Water and Glenmuir areas of Ayrshire. Bulletin of the Geological Survey of Great Britain, No. 40, 1–49.

Dewey, H. 1920. Arsenic and antimony ores. Special Report on the Mineral Resources of Great Britain, Memoir of the Geological Survey of Great Britain, Vol. 15.

Dunham, K, and 5 others. 1979. United Kingdom. 263–317 in Mineral deposits of Europe. Bowie, S H U, Kvalheim, A, and Haslam, H W (editors). Vol. 1. (London: Institute of Mining and Metallurgy Society.)

Eyles, V A. 1948. British regional geology: the South of Scotland. (2nd edition (revised)). Pringle, J (editor). (Edinburgh: H MS O.)

Eyles, V A, Simpson, J B, and MacGregor, A G. 1930. The economic geology of the Ayrshire coalfields, Area III, Ayr, Prestwick, Mauchline, Cumnock and Muirkirk. Memoir of the Geological Survey, Scotland.

Eyles, V A, Simpson, J B, and MacGregor, A G. 1949. Geology of Central Ayrshire. Memoir of the Geological Survey, Sheet 14 (Scotland).

Floyd, J D. 1982. Stratigraphy of a flysch succession: the Ordovician of W Nithsdale, S W Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 73, 1–9.

Floyd, J D. 1994. The derivation and definition of the `Southern Upland Fault': a review of the Midland Valley–Southern Uplands terrane boundary. Scottish Journal of Geology, Vol. 30, 51–62.

Floyd, J D. 1996. Lithostratigraphy of the Ordovician rocks in the Southern Uplands: Crawford Group, Moffat Shale Group, Leadhills Supergroup. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 86, 153–165.

Floyd, J D. 1999. Geology of the Carrick–Loch Doon district. Memoir of the British Geological Survey, Sheets 8W and 8E (Scotland).

Floyd, J D, and MacMillan, AA. in press. Geology around New Galloway and Thornhill (Sheets 9W and 9E) Memoir of the British Geological Survey, Sheets 9W and 9E (Scotland).

Floyd, J D, and Trench, A. 1989. Magnetic sus­ceptibility contrasts in Ordovician greywackes of the Southern Uplands of Scotland. Journal of the Geological Society of London, Vol. 146, 77–83.

Forsyth, I H, Hall, I H S, and MacMillan, A A. 1996. Geology of the Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland).

Geikie, A, Peach, B N, Jack, R L, Skae, H, and Horne, J. 1871. Explanation of Sheet 15. Dumfriesshire (North-West part); Lanarkshire (South part); Ayrshire (South-East part). Memoir of the Geological Survey, Scotland.

Gordon, J E. 1993. Greenock Mains. 542–544 in Quaternary of Scotland. (Geological conservation review series: 6). Gordon, JE, and Sutherland, DG (editors). (London: Chapman and Hall.)

Greig, D C. 1971. British regional geology: the South of Scotland. (3rd edition). (London: HMSO for British Geological Survey.)

Heinz, W, and Loeschke, J. 1988. Volcanic clasts in Silurian conglomerates of the Midland Valley (Hagshaw Hills inlier) Scotland, and their mean­ing for Caledonian plate tectonics. Geologische Rundschau, Vol. 77/2, 453–466.

Henderson, C M B, Foland, K A, and Gibb, F G F. 1987. The age of the Lugar sill and a discus­sion of the Late-Carboniferous/Early Permian sill complex of S W Scotland. Geological Journal, Vol. 22, 43–52.

Henderson, C M B, and Gibb, F G F. 1986. The petrology of the Lugar Sill, S W Scotland. Transactions of the Royal Society of Edinburgh: Section B: Applied Earth Sciences, Vol. 77, 325–347.

Hepworth, B C, Oliver, G J H, and McMurtry, M J. 1982. Sedimentology, volcanism, structure and metamorphism of the northern margin of a Lower Palaeozoic accretionary complex; Bail Hill-Abington area of the Southern Uplands of Scotland. 521–34 in Trench-forearc geol­ogy: sedimentation and tectonics on modern and ancient active plate margins. Leggett, JK (editor). Geological Society of London Special Publication, No. 10.

Hobson, G V. 1959. Barytes in Scotland with special reference to Gasswater and Muirshiel mines. 85–100 in The future of non-ferrous mining in Great Britain and Ireland (London: Institute of Mining and Metallurgy.)

Holden, WG. 1977. Western Scotland. 1–17 in INQUA X Congress 1977. Guidebook for excur­sion A12. Price, RJ(editor). (Norwich: Geo Abstracts.)

Holliday, D W. 1985. Devonian and Carboniferous basins. 84–109 in Geothermal Energy – the potential in the United Kingdom. Downing, R A, and Gray, D A(editors), (London HMSO for British Geological Survey.)

Hughes, R A. 1989. Graptolite biostratigraphy of some sections in the Sanquhar region.British Geological Survey Technical Report, WH/89/476R.

Lumsden, G I. 1964. The Limestone Coal Group of the Douglas Coalfield, Lanarkshire. Bulletin of the Geological Survey of Great Britain, No. 21, 37–71.

Lumsden, G I. 1965. The base of the Coal Measures in the Douglas Coalfield, Lanarkshire. Bulletin of the Geological Survey of Great Britain, No. 22, 80–91.

Lumsden, G I. 1967a. The Carboniferous Limestone Series of Douglas, Lanarkshire. Bulletin of the Geological Survey of Great Britain, No. 26, 1–22.

Lumsden, G I. 1967b. Intrusive coal at Douglas in Scotland. Scottish Journal of Geology, Vol. 3, 235–241.

Lumsden, G I. 1967c. The Upper Limestone Group and Passage Group of Douglas, Lanarkshire. Bulletin of the Geological Survey of Great Britain, No. 27, 17–48.

Lumsden, G I, and Davies, A. 1965. The bur­ied channel of the River Nith and its marked change in level across the Southern Upland Fault. Scottish Journal of Geology, Vol. 1, 134–143.

MacGregor, AG. 1944. Barytes in Central Scotland. Wartime Pamphlet of the Geological Survey of Great Britain: Scotland, No. 38.

MacGregor, M, Lee, G W, and Wilson, G V. 1920. The iron ores of Scotland. Memoir of the Geological Survey, Special Report of the Mineral Resources of Great Britain, Vol. 11. Iron ores (continued).

McGiven, A. 1968. Sedimentation and proven­ance of post-Valentian conglomerates up to and including the basal conglomerate of the Lower Old Red Sandstone in the southern part of the Midland Valley of Scotland. Unpublished PhD thesis, University of Glasgow.

McKerrow, W S, Leggett, J K, and Eales, M H. 1977. Imbricate thrust model of the Southern Uplands of Scotland. Nature, London, Vol. 267, 237–239.

McMurtry, M J. 1980a. Discussion of evidence for Caledonian subduction from greywacke detritus in the Longford–Down Inlier. Journal of Earth Sciences of the Royal Dublin Society, Vol. 2, 209–212.

McMurtry, M J. 1980b. The Ordovician rocks of the Bail Hill area, Sanquhar, South Scotland: Volcanism and sedimentation in the Iapetus Ocean. Unpublished PhD thesis, University of St Andrews.

Merriman, R J, and Kemp, S J. 1998. Metamorphism of the Lower Palaeozoic rocks of the New Cumnock district, southern Scotland. British Geological Survey Technical Report, WG/98/9.

Merritt, J W, and Gallagher, M J. 1989. Mineral resources of Cumnock and Doon Valley. British Geological Survey Technical Report, WA/89/64.

Muir, A, Hardie, H G M, Mitchell, R L, and Phemister, J. 1956. The Limestones of Scotland. Special Report on the Mineral Resources of Great Britain, Memoir of the Geological Survey of Great Britain, Vol. 37 (Scotland).

Paterson, I B, and Hall, I H S. 1986. Lithostratigraphy of the late Devonian and early Carboniferous rocks in the Midland Valley of Scotland. Report of the British Geological Survey, Vol. 18, No. 3.

Paterson, I B, McAdam, A D, and MacPherson, K A T. 1998. Geology of the Hamilton district. Memoir of the British Geological Survey, Sheet 23W (Scotland).

Peach, B N, and Horne, J. 1899. The Silurian rocks of Britain, Vol. 1: Scotland. Memoir of the Geological Survey of the United Kingdom.

Phillips, E. 1993a. Petrology of a series of volcaniclastic sandstones and associated igneous rocks, Sheet 15W (New Cumnock), Lanarkshire, Scotland. British Geological Survey, Mineralogy and Petrology Brief Report, M PS R/93/46.

Phillips, E. 1993b. Petrology of a series of volcaniclastic sandstones and basaltic to andesitic lavas exposed in Sheet 15W, Midland Valley, Scotland. British Geological Survey, Mineralogy and Petrology Brief Report, M PS R/93/12.

Phillips, E R. 1994a. Whole-rock geochemistry of the calc-alkaline Old Red Sandstone lavas, Sheet 15W (New Cumnock), Lanarkshire, Scotland. British Geological Survey, Mineralogy and Petrology Brief Report, WG/94/1.

Phillips, E. 1994b. Petrology of a series of volcaniclastic sedimentary and associated igneous rocks, Sheet 15W (New Cumnock), Lanarkshire, Scotland. British Geological Survey, Mineralogy and Petrology Brief Report, WG/94/26.

Phillips, E. 1995. Petrology of a suite of sedimentary and igneous rocks Sheet 15W, New Cumnock , Scotland. British Geological Survey, Mineralogy and Petrology Short Report, WG/95/47.

Phillips, E R, and Smith, R A. 1995. The petrology and provenance of the Lower Old Red Sandstone, New Cumnock (Sheet 15W), Scotland. British Geological Survey, Mineralogy and Petrology Technical Report, WG/95/31.

Phillips, E R, and Smith, R A. 1996. The petrology and geochemistry of the Bail Hill Volcanic Group and its relationship to other Ordovician basaltic volcanic rocks in the Southern Uplands of Scotland. British Geological Survey Technical Report, WG/96/46.

Read, W A. 1988. Controls on Silesian sedimentation in the Midland Valley of Scotland. 222–241 in Sedimentation in a synorogenic basin complex: the Upper Carboniferous of northwest Europe. Besly, B M, and Kelling, G (editors). (Glasgow and London: Blackie and Son.)

Read, W A. 1989. The interplay of sedimentation, volcanicity and tectonics in the Passage Group (Arnsbergian, E2 to Westphalian A) in the Midland Valley of Scotland. 143–152 in The role of tectonics in Devonian and Carboniferous sedimentation in the British Isles. Arthurton, R J, Gutteridge, P, and Nolan, S C (editors). Occasional Publication of the Yorkshire Geological Society, No. 6.

Richey, J E, Anderson, E M, and MacGregor,A G. 1930. The geology of North Ayrshire. Memoir of the Geological Survey,, Sheet 22 (Scotland).

Robertson, T, Simpson, J B, and Anderson, J G C. 1949. The limestones of Scotland. Special Report on the Mineral Resources of Great Britain, Memoir of the Geological Survey of Great Britain, Vol. 35 (Scotland).

Robins, N S. 1990. Hydrogeology of Scotland. London H MS O for British Geological Survey.

Rolfe, W D I. 1961. The geology of the Hagshaw Hills Silurian inlier, Lanarkshire. Transactions of the Edinburgh Geological Society, Vol. 18, 240–269.

Rolfe, W D I, and Fritz, M A. 1966. Recent evidence for the age of the Hagshaw Hills Silurian inlier, Lanarkshire. Scottish Journal of Geology, Vol. 2, 159–164.

Rollin, K E. 1978. Geophysical observations over the igneous suite at Hare Hill, Southern Upland Fault, September 1978. Institute of Geological Sciences, Applied Geophysics Unit, Mineral Reconnaissance Report (unpublished).

Rushton, A W A. 1995. Graptolites from the area north of Sanquhar. British Geological Survey, Biostratigraphy and Sedimentology Group Report, WH/95/203R.

Rushton, A W A. 1996. Graptolites south of Kirkconnel, Sanquhar. British Geological Survey, Biostratigraphy and Sedimentology Group Report, WH/96/263R.

Scott, B. 1967. Barytes mineralisation at Gasswater mine, Ayrshire, Scotland. Transactions of the Institution of Mining and Metallurgy (Section B: Applied earth science), Vol. 76, B4–51.

Simpson, J B, and MacGregor, A G. 1932. The economic geology of the Ayrshire coalfields, Area I V, Dailly, Patna, Rankinston, Dalmellington and New Cumnock. Memoir of the Geological Survey, Scotland.

Simpson, J B, and Richey, J E. 1936. The geology of the Sanquhar Coalfield and adjacent basin of Thornhill. Memoir of the Geological Survey, Scotland (Economic).

Smedley, P L. 1986. The relationship between calc-alkaline volcanism and within-plate continental rift volcanism: evidence from Scottish Palaeozoic lavas. Earth and Planetary Science Letters, Vol. 77, 113–128.

Smith, J. 1898. The drift or glacial deposits of Ayrshire. Transactions of the Geological Society of Glasgow, Vol. 11 (Supplement), 1–134.

Smith, R A. 1993. Explanation for 1:10 000 Sheet N S72S E (Auchendaff). British Geological Survey Technical Report, WA/93/34.

Smith, R A. 1994. Explanation for 1:10 000 Sheet N S72S W (Cairn Table). British Geological Survey Technical Report, WA/94/09.

Smith, R A. 1995a. Explanation for 1:10 000 Sheet N S71N W (Auchtitench). British Geological Survey Technical Report, WA/95/18.

Smith, R A. 1995b. Explanation for 1:10 000 sheet N S71S W (Kirkconnel). British Geological Survey Technical Report, WA/95/34.

Smith, R A. 1995c. The Siluro-Devonian evolution of the southern Midland Valley of Scotland. Geological Magazine, Vol. 132, 503–513.

Smith, R A. 1996a. Explanation for 1:10 000 Sheet N S62S E (Gass Water). British Geological Survey Technical Report, WA/96/22.

Smith, R A. 1996b. Explanation for 1:10 000 Sheet N S61N E Craigdullyeart. British Geological Survey Technical Report, WA/96/28.

Smith, R A. 1997. Explanation for 1:10 000 Sheets N S71S E and N S71S E. British Geological Survey Technical Report, WA/97/21.

Smith, R A. 1999. Geology of the New Cumnock district. Explanation for 1:50 000 Sheet 15W, Scotland.

Soper, N J, Strachan, R A, Holdsworth, R E, Gayer, R A, and Greiling, R O. 1992. Sinistral transpression and the Silurian closure of Iapetus. Journal of the Geological Society of London, Vol. 149, 871–880.

Stedman, C. 1988. Namurian E1 tectonics and sedimentation in the Midland Valley of Scotland: rifting versus strike-slip influence. 242–254 in Sedimentation in a synorogenic basin complex: the Upper Carboniferous of northwest Europe. Besly, B M, and Kelling, G (editors). (Glasgow and London: Blackie and Son.)

Stephens, W E, and Halliday, A N. 1984. Geochemical contrasts between late Caledonian granitoid plutons of northern, central and southern Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 75, 259–273.

Stone, P, Floyd, J D, Barnes, R P, and Lintern,B C. 1987. A sequential back-arc and foreland basin thrust duplex model for the Southern Uplands of Scotland. Journal of the Geological Society of London, Vol. 144, 753–764.

Stone, P, Kimbell, G S, and Henney, P J. 1997. Basement control on the location of strike-slip shear in the southern Uplands of Scotland. Journal of the Geological Society of London, Vol. 154, 141–144.

Styles, M T, Perez-Alverez, M, and Floyd, J D. 1995. Pyroxenous greywackes in the southern Uplands and their petrotectonic implications. Geological Magazine, Vol. 132, 539–547.

Styles, M T, Stone, P, and Floyd, J D. 1989. Arc detritus in the Southern Uplands: mineralogical characterization of a “missing” terrane. Journal

of the Geological Society of London, Vol. 146, 397–400.

Syba, E. 1989. The sedimentation and provenance of the Lower Old Red Sandstone Greywacke Conglomerate, Southern Midland Valley, Scotland. Unpublished PhD thesis, University of Glasgow.

Thirlwall, M F. 1981. Implications for Caledonian plate tectonic models of chemical data from volcanic rocks of the British Old Red Sandstone. Journal of the Geological Society of London, Vol. 138, 123–138.

Wellman, C H, and Richardson, J B. 1993. Terrestrial plant microfossils from Silurian inliers of the Midland Valley of Scotland. Palaeontology, Vol. 36, 155–194.

Wilson, G V. 1921. The lead, zinc, copper and nickel ores of Scotland. Special Report on the Mineral Resources of Great Britain, Memoir of the Geological Survey, Scotland, Vol. 17.

Wilson, R B. 1989. A study of the Dinantian marine macrofossils of central Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 80, 91–126.

Index to the 1:50 000 Series maps of the British Geological Survey

The map below shows the sheet boundaries and numbers of the 1:50 000 Series geological maps. The maps are numbered in three sequences, covering England and Wales, Northern Ireland, and Scotland. The west and east halves of most Scottish 1:50 000 maps are published separately. Almost all BGS maps are available flat or folded and cased.

The area described in this sheet explanation is indicated by a solid block.

(Index map)

British geological maps can be obtained from sales desks in the Survey's principal offices, through the BGS London Information Office at the Natural History Museum Earth Galleries, and from BGS-approved stockists and agents.

Northern Ireland maps can be obtained from the Geological Survey of Northern Ireland.

Figures and plates

Figures

(Figure 1) Geological succession in the New Cumnock district.

(Figure 2) Simplified geology of the New Cumnock district.

(Figure 3) Ordovician: Leadhills Supergroup of the district.

(Figure 4) Silurian strata of the district.

(Figure 5) Siluro–Devonian rocks of the district.

(Figure 6) Carboniferous rocks of the district.

(Figure 7) Correlation of the Limestone Coal Formation.

(Figure 8) Correlation of the Upper Limestone and Passage formations.

(Figure 9) Representative sections of the Coal Measures.

(Figure 10) Details of igneous intrusions in the district.

(Figure 11) Quaternary deposits of the district.

(Figure 12) Key environmental issues within the district.

Plates

(Plate 1) Coarsening-up conglomerate bed containing andesitic lava clasts, above a medium-grained sandstone within the Auchtitench Formation [NS 6669 1510] (D5377).

(Plate 2) McDonald Limestones, the topmost member of the Lower Limestone Formation, showing a small fault downthrowing to the left in a quarry south of Muirkirk [NS 6925 2595] (D5378).

(Plate 3) Glaciofluvial sand and gravel below an upper till unit at Greenock Mains: a lower till is exposed in the river [6305 2745] (D5389).

(Front cover) Loch o'th'Lowes with the New Cumnock coalfield in the low ground and the former Knockshinnoch colliery and restored opencast in the distance. Glen Afton cuts through Ordovician rocks on the skyline (taken from [NS 600 152]) (D5369).

(Rear cover) Geology of the New Cumnock district

(Index map) Index to the 1:50 000 Series maps of the British Geological Survey

Figures

(Figure 3) Ordovician: Leadhills Supergroup of the district

(Figure 4) Silurian strata of the district

(Figure 5) Siluro–Devonian rocks of the district.

(Figure 6) Carboniferous rocks of the district.

(Figure 10) Details of igneous intrusions in the district

(Figure 11) Quaternary deposits of the district

(Figure 12) Key environmental issues within the district