Figures and photographs

Photographs

(Spireslack_1 P1): Section showing McDonald Limestones to the left of the rucksack and the Hurlet Limestone to the right of the rucksack. © BGS, NERC.

(Spireslack_1 P2): 3 m thick section of the brown-yellow bedded Hurlet Limestone overlying dark-grey fossiliferous mudstone (Lawmuir Formation). © BGS, NERC.

(Spireslack_1 P3): Crinoid columns and brachiopods seen within mudstone below the Hurlet Limestone, (Lawmuir Formation). © BGS, NERC.

(Spireslack_1 P4): Ironstone bands within the mudstones (Lawmuir Formation). © BGS, NERC.

(Spireslack_2 P1): Palaeogene dyke intruding mudstones and siltstones of the Limestone Coal Formation. © BGS, NERC.

(Spireslack_2 P2): The same dyke exposed in the main scarp, cutting the Limestone Coal Formation. Note, where the dyke is in contact with coal it is altered to white trap: the result of volatiles released during intrusion of magma into carbonaceous rocks (e.g. coals, mudstones). © BGS, NERC.

(Spireslack_2 P3) Development of small thrust faults within the Limestone Coal Formation, highlighted by ironstone layers. The stronger ironstone layer is buckled and faulted — the same structures are not observed in the mudstone as it is a weaker unit, and deforms along multiple internal fractures. © BGS, NERC.

(Spireslack_2 P4) Internal fractures display heavily polished surfaces, evidence of the rocks on either side moving past each other (see right image). © BGS, NERC.

(Spireslack_3 P1): The fault zone and associated relay ramp structures are spectacularly exposed, highlighting important fault architecture components such as displacement length profiles (important for predicting how long fault traces are and where their maximum displacement is), relay ramp evolution (geometries of these are important for modelling fluid migration across rock volumes) and damage zone features associated with a 5 m displacement fault. Looking up-slope, toward the north-east. © BGS, NERC

(Spireslack_3 P2): Detail of mineralised slip surface along fault plane. Calcite veining is extensive across the fault planes, and has also been polished by fault movement (evidenced by development of slickenlines). Multiple generations of calcite are found at the site suggesting multiple phases of faulting.© BGS, NERC

(Spireslack_3 P3): Trilobite (Paladin sp.) seen on the McDonald Limestone pavement but no longer present due to erosion of the flaky surface.© BGS, NERC

(Spireslack_4 P1): Two approximately 1 m thick quartz dolerite dykes merge near the top of the limestone pavement. The leftmost dyke has a linear trend, whereas the rightmost dyke curves to merge with it in the centre of the photograph. The intruding dolerite has locally distorted the limestone and baked it at its contact. © BGS, NERC.

(Spireslack_4 P2): Limestone which has been baked at the dyke margin. Calcite mineralisation associated with the intrusion runs parallel to the dyke's contact with the limestone. © BGS, NERC.

(Spireslack_4 P3): Much of the lower part of the dyke in the scarp is covered in spoil and vegetation. Where the dyke cuts organic rich layers (i.e. coal or mudstone) the dyke has been altered to white trap. © BGS, NERC.

(Spireslack_5 P1): Fossilised shark spine preserved in the McDonald Limestone. This shows that during the Carboniferous in Spireslack, sharks were swimming in shallow, warm seas when Scotland was close to the equator. © BGS, NERC.

(Spireslack_5 P2): Crescent shaped 2 m wide markings (outlined in dashed green circle) are found on the limestone surface, created by machinery during coal extraction. © BGS, NERC.

(Spireslack_5 P3): Trace fossils litter the surface of the McDonald Limestone pavement. The dark branching structures in the photo are the fossilised traces of creatures which would have travelled the seabed surface of the pre-lithified limestone for food. These tracks can be up to 10 cm long — there are also mm- long tracks preserved on this surface. © BGS, NERC

(Spireslack_6 P1): Fault plane with well-preserved slickenlines and smearing of limestone layers across fault plane. The dyke cross cutting the fault is indicated with an arrow. © BGS, NERC.

(Spireslack_6 P2): The same fault observed in the scarp, where it is seen in section cutting mudstones, coal and sandstones. © BGS, NERC. This fault is best observed from the northern limestone pavement as its features are obscured up close.

(Spireslack_7 P1): Spectacular fault structures, including relay ramps, limestone lenses and small faults have formed in response to faulting of the McDonald Limestone pavement . © BGS, NERC.

(Spireslack_7 P2): The fault is also seen in the scarp of the void — however, the damage associated with the west side wall of the fault is not as obvious in this section view as it is on the limestone pavement. The fault also displaces a Palaeogene dyke. © BGS, NERC.

(Spireslack_7 P3): Fault breccia, formed from fracturing and rotation of the stiff McDonald Limestone along the main fault plane. Fault rocks can give an indication of how intense the faulting was and how often the sequence has been faulted. © BGS, NERC.

(Spireslack_7 P5): Foreground shows the faulting style of the seatearth, sitting stratigraphically above the McDonald Limestone. The main fault displacing the units is to the right of the photos, but the intense deformation recorded in the west wall of the fault by the limestone is less obvious in the seatearth — a result of the differing mechanical strengths of the units faulted. © BGS, NERC.

(Spireslack_8 P1): Fossilised roots (stigmaria) of Lepidodendron sp., a tree-sized fern, are abundant within the McDonald seatearth. © BGS, NERC.

(Spireslack_8 P2): Lepidodendron sp. tree cast within McDonald seatearth. Note erosive nature of seatearth in lower left — this is comprised mostly of stigmaria root fossils. © BGS, NERC.

(Spireslack_8 P3): Detail of stigmaria root within McDonald seatearth. The circular scars on the root surface are the preserved remains of smaller rootlets (stigmata) which were once attached and arranged radially around the stigmaria. © BGS, NERC.

(Spireslack_9 P1): Ankerite mineralisation within coal cleats (fractures within coal) and fault zones cutting coal. Ankerite is a carbonate mineral containing ferrous iron, which turns the mineral brown as a result of weathering. It is thought to be a product of late-stage diagenesis (Younger, 2004). © BGS, NERC

(Spireslack_9 P2): Johnstone Shell Bed exposed in a water-washed gully. Note fissile nature of beds which make it an easily erodible unit. © BGS, NERC.

(Spireslack_9 P3): Detail of the Johnstone Shell Bed, a marine band containing abundant calcareous brachiopods. © BGS, NERC.

(Spireslack_10 P1): Fault in the south wall, displacing rocks in an apparent normal sense down to the east (left of the image), but also to the north in an oblique sinistral fashion. The weaker fault rocks have been eroded along the fault plane, leaving a cleft marking the position of the fault. Sandstone tends to fracture when faulted — the fractured sandstone has washed out of the fault plane to form a localised debris cone half way up the scarp. Photo facing south. © BGS, NERC.

(Spireslack_11 P1): Section with the Limestone Coal Formation in the scarp at Spireslack. The dark band is the Muirkirk Nine Foot Coal. The left hand side of the image shows the original thickness of this seam, before it narrows and is replaced by packed mine waste. Photograph looking south-west toward main scarp. © BGS, NERC.

(Spireslack_11 P2): Wooden pit prop in situ within the coal workings. The wooden props were used to hold up the roof of the workings as the coal was extracted. The prop, sitting above packed mine waste in the photo, has since collapsed due to the overlying weight of rock (sandstone) above. © BGS, NERC.

(Spireslack_12 P1): Section of Limestone Coal Formation, showing a 5 metre coarsening upward sequence through mudstones to sandstones. © BGS, NERC.

(Spireslack_12 P2): Crinoid fragments are abundant within the sandstone. © BGS, NERC.

(Spireslack_13 P1): 20 cm thick band of cannel coal set within the Muirkirk Nine Foot Coal seam. © BGS, NERC.

(Spireslack_13 P2): Section of the Limestone Coal Formation showing 2 metre section of coal with the light grey band of cannel coal, with overlying sandstone bed (brown-orange coloured rock). © BGS, NERC.

(Spireslack_14 P1): Eastward edge of old mine workings seen in the south wall. The thick 'pillars' of coal (P) beneath the sandstone bed were used to prop up the roof of the mine workings whilst the coal was extracted from between pillars. © BGS, NERC.

(Spireslack_14 P2): Western edges of old mine workings seen in the south wall. The random blocks of sandstone and coal can be seen to the left of the photo, this is infilling the space devoid of coal which has been extracted. The 'pillar' of coal (P) can be seen to the right of these blocks. © BGS, NERC. P

(Spireslack_14 P3): The middle pillar of this section (P) can be seen in the middle of the photograph. The sandstone bed above the coal, on either side of the pillar, has collapsed after the coal was extracted. © BGS, NERC.

(Spireslack_14 P4): Viewing platform, facing west. Good place for visualising the true dip of the strata (wall facing photo) compared to the apparent dip of the strata (seen on the scarp). © BGS, NERC.

(Spireslack_15 P1): The Calmy Limestone beds looking to the west. The Calmy Limestone is composed of three individual thick 'leaves', separated by marine mudstones. The Calmy Limestone here sits above the Gill Coal. © BGS, NERC.

(Spireslack_15 P2): Pyrite nodules are present in the upper half of the Gill Coal. The presence of pyrite (iron and sulphur rich) in the Gill Coal indicates oxygen starved conditions at time of deposition, and potentially within a more marine influenced environment (coals produced in fresh water environments contain less pyrite than those formed in marine). © BGS, NERC.

(Spireslack_16 P1): Peat overlying 'bleached' till above fining ponds. © BGS, NERC.

(Spireslack_16 P2): View south from access pond toward two generations of mining waste. Note the older generation on the right has been naturally colonised by shrubs, vegetation and low growing trees, whereas the newer generation on the left, piled against the older generation, is only just starting to recolonise. The boundary between the two generations is indicated with a black dashed line. © BGS, NERC.

(Spireslack_17 P1): Exposure of the Swanshaw Sandstone Formation, at the eastern edge of the Spireslack SCM. © BGS, NERC.

(Spireslack_17 P2): Peat overlying bleached till (formation of podzol) above the Swanshaw Sandstone

(Spireslack_18 P1): Stacked sandstone bodies within Area B1 at Spireslack. These thick tabular massive bodies of sandstone represent stacked bars formed as part of a channel complex. Closer inspection reveals cross- bedding within these stacked bars which can be used for palaeocurrent analysis. To improve access, spoil heap in front section should be levelled and the section cleared of loose material. © BGS, NERC.

Cover and cover photographs

(Front cover)

(Cover photo 1)

(Cover photo 2)

Overview of locality photographs

(Overview of Locality 1). Site boundary includes key rock exposures, immediate access to site and potential viewing points to the site. Photo looking to the west, taken from above the scarp looking down on to site.

(Overview of Locality 2). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. Photo looking north.

(Overview of Locality 3). Site boundary includes key rock exposures, a buffer zone around the exposures to place the fault in context, to include the damage zone of the fault in the limestone pavement and to allow room for viewpoints at the base of the site.

(Overview of Locality 4) and 4b (north and south wall respectively). Site boundary includes key rock exposures, immediate access to site and potential for viewpoints to the site at the base of the limestone pavement. Photo on the left looking to the north, photo on right taken looking south toward scarp.

(Overview of Locality 5). Site boundary includes key rock exposures (from the shark spine at the base of the pavement to the crescent shaped digger marks near the top), immediate access to site and viewpoints to the site. Photo taken from scarp looking south.

(Overview of Locality 6). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. Photo taken from scarp, looking north.

(Overview of Locality 7) and 7b (north and south wall respectively). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. Left photo taken from scarp looking to the north, and right hand photo taken looking to the equivalent fault on the south of the void.

(Overview of Locality 8). Site boundary includes key rock exposures, immediate access to site and suggested viewpoints to the site. Tree casts are highlighted by arrows.

(Overview of Locality 9). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. Photo looking toward the west-south-west in lower part of void.

(Overview of Locality 10). Site boundary includes key rock exposures, immediate access to site and potential viewpoints to the site (foreground in right of photo overview). Note active debris cone accumulating half way up main scarp. Photo looking to the south.

(Overview of Locality 11). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. View looking south onto scarp, at western edge of lower void.

(Overview of Locality 12). Site boundary includes key rock exposures and immediate access to site. Photo looking south toward the scarp, whilst standing at base of lower void.

(Overview of Locality 13). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site.

(Overview of Locality 14). Site boundary includes key rock exposures, from the underground coal workings to the trace of the dyke from locality 2.

(Overview of Locality 15). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. Photo taken looking south toward eastern edge of the scarp.

(Overview of Locality 16). Site boundary includes key geological exposures (in this case peat and till sections within the north of the boundary, and two generations of spoil heap within the south part of the site boundary), immediate access to site and viewpoints to the site.

(Overview of Locality 17). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site.

(Overview of Locality 18). Site boundary includes key rock exposures, immediate access to site and viewpoints to the site. View looking toward the north from the old car park levelled area at the south of the Spireslack SCM.

Figures

(Figure 1) Generalised Carboniferous geology of the Midland Valley of Scotland, showing the major faults that bound the Midland Valley. The map also shows the locations of prospected and active surface coal mines in Carboniferous strata. Sites owned by the Scottish Mines Restoration Trust (SMRT) are also indicated, with the locations of Spireslack (S) and Mainshill Wood (M) SCMs highlighted.

(Figure 2) Stratigraphical framework for coal-bearing strata at Mainshill Wood and Spireslack SCMs. The key coal units and lithological markers referred to in this audit are highlighted in the more detailed columns.

(Figure 3) 1:50 000-scale geological map within the Spireslack SCM site area. The oldest rocks within the site are exposed at the far east of the site boundary, and are sandstones belonging to the Swanshaw Formation (Devonian in age). These rocks are separated from the Carboniferous rocks by a major north-trending fault. The Carboniferous strata have been folded into a broad north-easterly syncline across the site, with the strata offset by many faults with a dominant north to north-north-easterly trend.

(Figure 4) 1:50 000-scale geological map within the Mainshill Wood SCM site area. The oldest rocks within the site belong to the Devonian age Biggar Volcanic Formation, situated to the south of the Kennox Fault in the southern portion of the site. The Carboniferous strata lie to the north of the Kennox Fault where they are sub-vertically arranged. The rocks become younger towards the north.

(Figure 5) Map showing locations of nearby SSSI and GCR sites in the areas neighbouring Spireslack and Mainshill Wood SCMs.

(Figure 6) Aerial view of Spireslack SCM, showing locations of the audited geodiversity sections within the mine. The number of the site corresponds with the equivalent audited site described in the report.

(Figure 7) Location map of the Glenbuck Ironworks Scheduled Ancient Monument site. © BGS, NERC

(Figure 8) Bell-pits at southern edge of Spireslack SCM. View looking toward the south-west. These disused bell-pits were historically associated with ironstone and limestone mining. © BGS, NERC

(Figure 9) The ruins of the Glenbuck Ironworks Furnace are visible at the base of the tree in the centre left of the photo. The furnace has been buried by later generations of mine waste. Photo copyright Mike Browne.

(Figure 10) Outline of Mainshill Wood SCM, with extent of exposed face digitised in western sector.

(Figure 11) Panoramic photograph towards the south-western corner of Mainshill Wood SCM, revealing spectacular sub-vertically dipping Carboniferous strata. The dark layers are coal seams and mudstones, whilst lighter layers are sandstones and limestones. The rocks are increasingly younger toward the right of the photo (toward the north). Note 4x4 vehicle for scale. Photo taken September 2013 before main void was significantly flooded by groundwater. © BGS, NERC

(Figure 12) Main face of Mainshill Wood SCM showing the sub-vertical strata. The darker layers visible in the mined face are coal seams (the Manson Coals in the centre of the image), whilst the lighter layers are sandstones and limestones. Note high water level restricting access to base of exposures. Photo taken June 2014. © BGS, NERC

(Figure 13) View toward the south-west corner of the Mainshill Wood SCM main face, revealing the flower structure related to the Kennox Fault. The flower structure is the area of folded and faulted strata to the left of the inclined strata in the photo. © BGS, NERC

(Figure 14) The Manson Coals seen in the main face at Mainshill Wood SCM. From left to right, the Lower, Middle and Upper Manson Coal seams. The Manson Coals are not seen elsewhere in natural sections; therefore Mainshill Wood SCM provides the only opportunity to study these coals. © BGS, NERC

(Figure 15) Location of sites within Appendix 1 at Spireslack SCM.

References