The Building Stones of Oldham, and Glodwick Lows - Sunday September 18th 2005
Fourteen of us convened on a damp morning to one of those Oldham days which could go either way. Happily the drizzle cleared and the temperature rose throughout a most informative and enjoyable day lead by Steve Darlington of the OUGS.
The Building Stones walk started with some controversy at The Civic Centre complex. The building is predominately clad with Portland stone. However to the southeast side of the Queen Elizabeth Hall the cladding was made up of a ochre coloured metamorphic rock with prismatic shiny black crystals 0.5-1 x 10-15mm randomly arraigned in the plane of the dominant foliation. Occasional pyrite was present in an otherwise fine grained matrix. Seeing it only in one dimension (taking a hammer to it was not an option) made further identification impossible, so it remains an enigma.
With too many stops to mention individually here, Steve outlined the history of Oldham and how the original street layout is now partially overlain by new commercial building of the 1970s onwards. Propelled along High Street to get away from the loud music emanating from Burger King, we stopped outside Littlewoods to admire the Rapakivi-style granite facing. Rapakivi or ‘Baltic Brown’ is a hornblende-biotite granite with large rounded orthoclase crystals mantled with oligoclase. Rapakivi is Finnish for rotten and describes the tendency of the granite to easily weather. Well polished, there was little sign of it rotting here, which is more than can be said for the travertine facing McDonalds opposite. In places the naturally occurring holes in the rock, made by gas escaping during lithification, which are artificially filled as part of the preparation process, have become holes again and the polish has dulled giving a grey-white shabby pitted appearance. Older buildings in town are predominantly constructed of sandstones and native granite, not the corporate or ‘signature’ exotic claddings favoured by modern enterprises.
The coarse golden sandstone of the Lyceum on Union Street and the water lain Carboniferous sandstone of the Town Hall (good ripple marks) and the Arts Centre (where splashing Oldham rain has badly weathered the street level courses and the verticals of the window frames) are all good examples of Victorian stonework. The combination of Balmoral and Cornish Granites (pillars and plinths respectively) in the portico of the HBSC Bank on Queen Street displays an elegance of design and quality rock.
The distinctively pink local sandstone from Oldham Edge is seen to good effect in the Town House Restaurant on Greaves Street and the portico of No.11 Church Lane, a lone surviving Georgian street with elegant pavement setts leading to the Parish Church of St Mary’s, a somewhat modest Victorian construction of coarse millstone grit from the Chew Valley to the east of the town. In contrast, the vestry is made of red/pink Triassic sand stone rescued from a church elsewhere in the town, demolished in 1967.
Assembling for the afternoon trip to Glodwick Lows (NGR 394 185) very recent deposits of unwanted furniture and car parts littered the entrance to a signposted trail through a disused opencast coal pit. The Westphalian A stratigraphy is well displayed on the main quarry face, consisting of interbedded deltaic sandstones, shales, fireclay and mudstones with the Oldham Great Mine and Blenfire Seam coal beds exposed. To everyone’s delight, many fossils, mainly Carbonicola and traces of plant stems, were found in the dark shales. Climbing to the NW of the main face, the second major unresolved controversy of the day unfolded with the discovery of shale blocks with impressions on thin laminae resembling a running bond brickwork with the individual ‘bricks’ measuring c 100mm x 10-20mm. Some thought it was fossilised bark, it certainly resembled some modern bark but no one was certain. It might be a thin veneer of coal fracturing to form the regular pattern. If anyone has better suggestions we would certainly like to know. The day concluded on top of the Lows where Steve put the stratigraphy now under our feet into its wider regional context with fantastic views to Winter Hill in the north through Saddleworth and Hartshead Pike in east then south across Manchester to the Cheshire plain.
Click here to see some photos taken on this field trip.