The Geology How Old Are the Rocks?
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to the whole route is planned for the future. the for planned is route whole the to short geotrails provide a way of exploring them. A geological guide guide geological A them. exploring of way a provide geotrails short www.lancashire-geologists.co.uk geological landscapes of Lancashire and the Yorkshire Dales. These These Dales. Yorkshire the and Lancashire of landscapes geological Ribbleyears. alleyrecent in projects The Ribble Way provides a ready-made excursion into many of the the of many into excursion ready-made a provides Way Ribble The The Geology How old are the rocks? organisations have worked together on a number of of number a on together worked have organisations Douglas Ribble Way Ribble has very close ties with GeoLancashire and the two two the and GeoLancashire with ties close very has River River Longton The Ribble valley's oldest rocks are field excursions which are open to all. The group group The all. to open are which excursions field Walk No1 Walk Preston Preston Ribblehead sandstones and limestones which were organises a programme of winter lectures and summer summer and lectures winter of programme a organises Age of Rocks Walk No2 Walk Ribble Brockholes Brockholes St Anne’s St River River laid down 410-510 million years (Ma) ago Preston regardless of their level of geological knowledge. It It knowledge. geological of level their of regardless Lytham Permo-Triassic Walk No3 Walk Ribchester in the Ordovician and Silurian periods. organisation and welcomes members and guests guests and members welcomes and organisation Millstone Grit (Namurian) Walk No4 Walk Dinckley Blackpool Horton Fell They have been affected by folding and in Clitheroe. It is an informal, friendly and inclusive inclusive and friendly informal, an is It Clitheroe. in Carboniferous Clitheroe Longridge Limestone (Dinantian) faulting during their long history. Around Group is a local branch of the GA which meets monthly monthly meets which GA the of branch local a is Group Stainforth Walk No5 Walk Ordovician-Silurian Pendle Hill Pendle Clitheroe Horton-in-Ribblesdale and Stainforth who are interested in Earth Sciences. The Lancashire Lancashire The Sciences. Earth in interested are who Settle these processes uplifted the older rocks to Hodder and actively promotes the study of geology to all all to geology of study the promotes actively and River River Gisburn Fleetwood (See timeline below) the surface, where today they are quarried The Geologists’ Association (GA) was formed in 1858, 1858, in formed was (GA) Association Geologists’ The Fell Easington for roadstone at Horton and Ingleton. The Geologists’ Association (LGGA) (LGGA) Association Geologists’ The Bay Rocks of Carboniferous age (360-290 Morecambe www.geolancashire.org.uk Ma) covered the older rocks and now Gisburn Settle found on the website. the on found dominate the landscape of the Ribble Stainforth several sites across the county, details of which may be be may which of details county, the across sites several valley. The river rises in an area of Clitheroe Ribblesdale a number of geotrail guides and other publications for for publications other and guides geotrail of number a the oldest Carboniferous rocks, the Horton in Horton geology and landscapes of Lancashire. It has produced produced has It Lancashire. of landscapes and geology Craven limestones, which have given Ingleborough Ribchester 1991 to protect and raise public appreciation of the the of appreciation public raise and protect to 1991 the Yorkshire Dales National Park its Ribblehead Ribble alley Geolancashire is a voluntary organisation founded in in founded organisation voluntary a is Geolancashire characteristic landscapes. The sink holes, Geo Lancashire Lancashire Preston caves and limestone pavements around Whernside Ingleborough, Whernside and Pen-y-ghent are produced by solution weathering of The Ribble Way Ribble The Walk 1 Walk POCKET Preston GUIDE these limestones. Overlying the limestone are Carboniferous ROCKS occurring in the study area in the study occurring ROCKS ARNSBERGIAN sandstones,CHOKERIAN gritstones andPENDLEIAN finer-grained Ribble alley sediments of Namurian 'Millstone Grit' This Ribble Valley Geotrail age (326–312 Ma). Erosion over millions Pocket Guide is just one of of years has removed much of this rock 280 Million Years Stephanian Westphalian Measures) (Coal NAMURIAN Grit) (Millstone DINANTIAN (Carboniferous Limestone) 1 Million years 370 5 pocket guides currently to form the dark moorland landscapes of Ribble alley Ribble alley Ribble alley Ribble alley Ribble alley available or in preparation POCKET GUIDE Bowland, Pendle Hill and Longridge Fell. CARBONIFEROUS STAGES 4500 2.5 65 135 195 235 280 The youngest370 solid415 rocks445 are of Permian515 590 Ribble alley Ribble alley Ribble alley Ribble alley Ribble alley Walk 1 Preston and Triassic age (290-205 Ma). These are POCKET GUIDE POCKET GUIDE POCKET GUIDE POCKET GUIDE POCKET GUIDE also sandstones but mostly reddish in Ribble alley Ribble alley Ribble alley Ribble alley Ribble alley 1 2 3 4 5 POCKET GUIDE POCKET GUIDE POCKET GUIDE POCKET GUIDE POCKET GUIDE colour; they form the coastal plain of West Walk 1 Preston Walk 2 Brockholes Walk 3 Ribchester Walk 4 Dinckley Gorge Walk 5 Clitheroe TRIASSIC PERMIAN CARBONIFEROUS DEVONIAN SILURIAN ORDOVICIAN CAMBRIAN ORIGIN OF EARTH QUATERNARY TERTIARY CRETACEOUS JURASSIC Lancashire and the Fylde. PERIOD or SYSTEM (Ma) Years Age/Million Millstone TIMESCALE THE GEOLOGICAL Grit (Gritstone), Rossendale CAINOZOIC MESOZOIC PALAEOZOIC PRECAMBRIAN ERA RIGS RIGS GeoLancashireRIGS GeoLancashireRIGS GeoLancashireRIGS GeoLancashire GeoLancashire The most recent deposits are less than Group Group Group Group Group 25,000 years old. Thick layers of glacial till (boulder clay) can be found especially on Details of these may be found on our website. We plan to THE GEOLOGICAL TIMELINE produce a further five Ribble Valley geotrail guides for the CARBONIFEROUSthe lower ground, while sands and gravels section from Clitheroe to Horton-in-Ribblesdale and details will characterise the hill margins. Post-glacial ORDOVICIAN SILURIAN DEVONIAN DINANTIAN NAMURIAN WESTPHALIAN STEPHANIAN PERMIAN TRIASSIC be available on the website as they are published. deposition includes alluvium on the river Million Years Ago 515 445 415 370 PENDLEIAN ARNSBERGIAN 280 235 195 This is a Quick Response (QR) code. When Warley floodplain, mud and sand in the estuary Pendle Wise Sabden Shales scanned with a smartphone (see below) it can Grit Grit and blanket peat over the higher hilltops. link you directly to a page on the GeoLancashire Gordale Scar Limestone Pavement website to provide you with more information Copster Green Sandstone about this walk. To scan a QR code you will THE GEOLOGICAL TIMELINE need a smartphone or tablet with a camera CARBONIFEROUS and an ‘app’ to read the code. You will also need access to the TRIASSIC PERMIAN STEPHANIAN WESTPHALIAN NAMURIAN DINANTIAN DEVONIAN SILURIAN ORDOVICIAN internet on your device. There are many free QR scanner apps GeoLancashireRIGS available. You can download them from sites like www.qrstuff. 205 250 290 307 312 326 360 410 440 510 Group com and www.qrdroid.com Million Years Ago www.geolancashire.org.uk Sherwood Sandstone Maps used in this leaflet contain Ordnance Survey data © Crown copyright and database right 2012 Preston Leaflet A3.indd 1 10/01/2013 19:58 GeoLancashireRIGS Ribble alley Walk 1 Preston ROUTE 1 Group granite for the upper parts. Both rocks are coarse-grained Walk 1 Preston sandstones of Carboniferous age. The later western extension is made from red Sherwood Sandstone of There is little sign in Preston Triassic age. of the underlying rock, but careful examination of the river The second bridge was built, from Pendle Grit and red 4 brick, to carry the former East Lancashire railway but 5 3 banks will reveal clues to the now carries a public footpath and cycleway over the river. geological history of this area. 3 Walton Bridge carries the A6 road across the river. 1 Penwortham Old Bridge is built from Fletcher The bridge is built from two different sandstones. The On Street 1 Parking Bank Grit of Carboniferous age, a coarse-grained older downstream side was built in the 1780s using 1 kilometre sandstone from Whittle Hill near Chorley. This rock Fletcher Bank Grit probably from the Chorley area - grey 2 0 250m 500m 750m 1km has large grains of quartz, indicating that it was and very coarse with lots of big pebbles The western laid down by fast-flowing water with the energy to extension was built between 1939-1950 with arches of move large particles. The deck is sett-paved with reinforced concrete, while the stone facings and parapet Haslingden Flags, also of Carboniferous age from are made from Pendle Grit from Longridge, the stone Start: Parking is possible for a small number of cars on and followed as far as the Bridge Inn where the river the Rossendale area. used in many of Preston’s public buildings. Broadgate and Riverside on the north side of the river channel can be accessed. near Penwortham Bridge where the walk starts. This is Pass over Walton Bridge then turn left into Ashworth about 10 minutes’ walk from the Railway station. The bridge stands on an outcrop of Sherwood Grove, then Boulevard which leads to Avenham Park. sandstone, a red coloured rock of Triassic age, Route: From the bridge, follow Riverside Road then The riverside path continues into Miller Park, back the footpath upstream on the south side of the river. under the main railway bridge into Riverside and the 200-250 million years old, laid down in desert Pass under the Ribble Viaduct, over a footbridge and start of the walk. conditions not unlike those of the Sahara Desert under the disused East Lancashire Railway viaduct. Distance: Approximately 6km (3.75 miles) today. The bridge design incorporates Sherwood Keeping to the river bank, pass under the old tramway Maps: OS Pathfinder 1:25K Sheet 688; Preston A – Z Sandstone, the rock on which Preston is built.