Hambleton Quarry

From Earthwise
Jump to navigation Jump to search

C N Waters (BGS)

Hambleton Quarry, Bolton Abbey, North Yorkshire [SE 056 532][edit]

DIAGRAM TO GO HERE
Map extract from DigMap50k showing the location of Hambleton Quarry and the distribution of Pendleside Limestone Formation (in turquoise), with overlying Bowland Shale Formation present to SE and underlying Hodder Mudstone Formation to NW.

Summary[edit]

This disused quarry contains a folded and faulted succession from the uppermost part of the Hodder Mudstone Formation through to the basal part of the Bowland Shale Formation. The quarry is most notable for the exposure of the Pendleside Limestone Formation. The quarry at is located on the south-east flank of the Skipton Anticline. The tectonically complex exposure extends from the uppermost part of the Hodder Mudstone Formation through to the basal part of the Bowland Shale Formation. The quarry is most notable for the exposure of the Pendleside Limestone Formation. The southern and northern faces are described separately.

1. Southern face[edit]

The southern face is deformed into south-verging asymmetric folds and is transected by north-west to south-east trending sinistral strike-slip faults.

Hambleton Quarry (south face) carbonate turbidites of Pendleside Limestone Formation with capping of Bowland Shale Formation, showing asymmetric folding. P773133. Hambleton Quarry (south face) detail from section shown in P773133 showing syn-sedimentary deformation in upper part of Pendleside Limestone Formation. P773137. Hambleton Quarry (south face) lower leaf of carbonate turbidites of the Pendleside Limestone Formation in core of asymmetric anticline shown in P773133. Overlain by thin mudstone an in turn overlain by Tiddeman's Breccia. P773143.

Bowland Shale Formation

The topmost 3 m of the quarry face comprises black, unbioturbated, carbonaceous shale with rare thin limestone beds.

Pendleside Limestone Formation[edit]

This formation comprises an upper succession about 18 m thick, referred to by Hudson and Mitchell (1937) as the ‘Draughton Shales’, and a lower succession about 25 m thick, referred to as the Draughton Limestone.

The upper ‘Draughton Shales’ comprise the following succession, youngest at top (from Harrison, 1982):

Limestone, dark grey, thinly-bedded, common thin black shales 8.5 m
Limestone, dark grey 1.5 m
Shale 0.5 m
Limestone, mid-grey to dark grey, coarse arenite packstone, common crinoid, peloid, spine and foraminifera debris. Some fine silica and dolomite 2.3 m
Shale, thin interbedded argillaceous limestones 0.6 m
Limestone, dark grey, fine arenite packstone, some intraclasts. Some fine silica and common bioclastic silicification 3.7 m

Both Metcalfe (1981) and Cossey et al. (2004) show this succession to have a predominantly shaly lower and upper interval, with a thin flaggy sandstone at the base of the unit. The shales are described as being cherty and rich in phosphate nodules up to 5 cm diameter (Hudson and Mitchell, 1937) and the succession is bioturbated.

The ‘Draughton Limestone’ was described in detail by Harrison (1982), although this description is different to that of Metcalfe (1981) and Cossey et al. (2004). The section was relogged by C N Waters on 21st June 2011 and is described as follows, youngest strata at top:

Limestone, thin to thick planar bedded, upward-thickening beds in lower part, upward-thinning beds in upper part, gradational base c. 10 m
Mudstone, medium to dark grey, non-calcareous, with thin planar limestone beds, gradational base 0.9 m
Limestone, medium grey, pale brown weathered, coarse-grained sparry grainstone with crinoid ossicles, internally massive, finer grained, planar and wavy laminated in upper 0.18 m 0.8 m
Conglomerate (‘Tiddeman’s Breccia’), sub-rounded cobbles of pale grey micritic limestone and dark and pale grey sparry bioclastic limestone up to 0.16 m diameter with dark grey muddy matrix at base, fines up to grainstone with shaly top; sharp irregular base LINK TO LOCALITY IMAGE 1.88 m
Mudstone, medium to dark grey, non-calcareous, gradational base with interlamination with underlying limestone LINK TO LOCALITY IMAGE 0.01-0.16 m
Limestone, medium grey, fine bioclastic calcarenite with small crinoid ossicles, some dark grey chert bands, planar bedded up to 0.15 m thick, lowermost bed normal graded, coarse-grained above sharp planar base LINK TO LOCALITY IMAGE 0.55 m
Mudstone, dark grey and weakly calcareous at top passing down gradationally to pale brown and calcareous; planar laminated 0.4 m
Limestone, very fine-grained, massive, chert nodules toward top 0.5 m

A further succession of limestones, about 9.5 m thick, was previously recorded below the base of this section by Metcalfe (1981) and Cossey et al. (2004), but is now obscured by a vegetated shale-scree slope.

The interval above the ‘Tiddeman’s Breccia’ was formerly referred to as the ‘Upper Draughton Limestone’ or ‘Emmonsia Beds’ (Hudson and Mitchell, 1937). The limestones are typically darker and thinner bedded bioclastic and lithoclastic limestones with subordinate shale beds (Cossey et al., 2004).

The ‘Lower Draughton Limestone’ or ‘Breccia Beds’ of Hudson and Mitchell (1937) is dominated by thickly bedded limestones with a derived coral-brachiopod fauna and two distinctive limestone breccia beds, the lower of which is now obscured. The ‘Tiddeman’s Breccia’ was interpreted as occurring at an intra-Asbian unconformity and the presence of the conodont zonal boundary at the top of this limestone conglomerate may support this interpretation.

Key fossils:[edit]

Metcalfe (1981) provides a detailed description of the conodonts identified within the lower shaly beds of the ‘Draughton Shales’ of the Pendleside Limestone Formation and for the same beds Fewtrell and Smith (1978) record a sparse foraminiferal assemblage.

The ‘Upper Draughton Limestone’ or ‘Emmonsia Beds’ (Hudson and Mitchell, 1937) of the Pendleside Limestone Formation include a ‘Zaphrentid phase’ fauna summarised by Hudson and Mitchell (1937). Conodonts within this interval and basal part of the ‘Draughton Shales’ belong to the Gnathodus bilineatus Zone (Metcalfe, 1981), suggesting a late Asbian age. The complete limestone succession includes an abundant foraminiferal assemblage described by Fewtrell and Smith (1978).

Conodonts within the ‘Lower Draughton Limestone’ or ‘Breccia Beds’ of Hudson and Mitchell (1937) belong to the Lochriea (Gnathodus) commutata Zone (Metcalfe, 1981), suggesting an early Asbian age.

2. Northern face[edit]

On the northern face the succession is interpreted to be steeply overturned, and is transected by north-west to south-east trending sinistral strike-slip faults. The succession is described as follows, youngest at the top (logged by C N Waters on 21st June 2011):

Hambleton Quarry (NW face) showing section in overturned Pendleside Limestone Formation, including face with sole structures. P773154. Hambleton Quarry (NW face) showing Hodder Mudstone Formation in foreground, faulted against overturned Pendleside Limestone Formation in background. P773152.
Hambleton Quarry (NW face) showing burrows in calcarenite within overturned Pendleside Limestone Formation. P773149. Hambleton Quarry (NW face) showing Hodder Mudstone Formation in foreground, faulted against overturned Pendleside Limestone Formation in background. P773156.

Pendleside Limestone Formation

Mudstone, dark grey, calcareous, thin to very thin planar bedded >2 m
Limestone, orange-brown weathered, fine calcarenite, mainly thick-bedded with some mudstone interbeds. A sharp irregular base is interpreted as sole structures, with some chert present as veins and apparently replacing burrows, some recrystallized crinoid ossicles LINK TO IMAGE c. 4.5 m
Limestone, medium grey, pale brown weathered, fine calcarenite, thinly planar bedded and laminated, some wispy lamination and possibly cross-lamination, muddy on top 0.1 m 1.0 m
Mudstone, calcareous, medium grey, thinly planar laminated with thin limestone beds; gradational base 0.9 m
Limestone, pale brown, fine- to coarse-grained, planar bedded crinoidal calcarenite. Sharp basal bedding surface forming the local face of the quarry shows isolated burrows, possible brachiopod valves and what has the appearance of a bifurcating sole structures LINK TO LOCALITY IMAGE 1.6 m.

The Hodderense Limestone Formation, which regionally underlies the Pendleside Limestone Formation, is absent in the area of the Skipton Anticline, indicating that the base of the Pendleside Limestone Formation is marked by an unconformity in Hambleton Quarry.

Hodder Mudstone Formation[edit]

The lowermost unit described in the quarry is the Hodder Mudstone Formation (formerly Skibeden Shales with Limestones of Hudson and Mitchell, 1937), seen as discontinuous exposures toward the eastern end of the quarry (Cossey et al. 2004). The section is described as faulted against younger strata present to the west and comprising less than 10 m of thick dolomitic mudstone with subordinate silty limestone beds. LINK TO LOCALITY IMAGE.

See also[edit]

Pendleside Formation (PDL)

  • Hambleton Quarry

References[edit]

COSSEY, P J, RILEY, N J, ADAMS, A E, and MILLER, J. 2004. Chapter 6 Craven Basin. 257-302 in British Lower Carboniferous Stratigraphy. Geological Conservation Review Series No. 29. COSSEY, P J, ADAMS, A E, PURNELL, M A, WHITELEY, M J, WHYTE, M A, and WRIGHT, V P (editors). (JNCC, Peterborough.)

FEWTRELL, M D, and SMITH, D G. 1978. Stratigraphic significance of calcareous microfossils from the Lower Carboniferous rocks of the Skipton area, Yorkshire. Geological Magazine, Vol. 115, 255-271.

HARRISON, D J. 1982. The limestone resources of the Craven Lowlands: description of parts of 1:50 000 Geological Sheets 59, 60, 61, 67, 68 and 69. Mineral Assessment Report. Institute Geological Sciences, No. 116.

HUDSON, R G S, and MITCHELL, G H. 1937. The Carboniferous geology of the Skipton Anticline. Summary of Progress of the Geological Survey for 1935, 1-45.

METCALFE, I. 1981. Conodont zonation and correlation of the Dinantian and early Namurian strata of the Craven lowlands of Northern England. Report of the Institute of Geological Sciences, Vol. 80/10, 1-70.