3/21/21
Geology of the Yorkshire Dales
https://fossilhub.org/geology-yorks-dales/
Dr Liam Herringshaw [email protected]
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Today's timetable
l 2pm – Introduction & Early Palaeozoic
l 2.45pm – break
l 3pm – Lower Carboniferous
l 3.45pm – break
l 4pm – Upper Carboniferous
l & post-Carboniferous
l 5pm – finish!
Waltham (2007)
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A sedimentary primer
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Yorkshire Dales geology
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Why the Dales are there
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Buoyant old granite
The Askrigg Block
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Yorkshire's oldest rocks
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Yorkshire's oldest rocks
Thornton Force: Carboniferous rocks overlying metamorphosed Ingleton Group
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The Ingleton Group Intensely folded, deep marine, sedimentary rocks
Pecca Quarry, photograph © Ashley Dace 9
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Above the Ingleton, the Lakes
Windermere Supergroup (Ordovician-Silurian turbidites):
Horton Formation (Silurian), Dry Rigg Quarry, nr Helwith Bridge. Photograph © Karl and Ali 10
The Devonian is missing
Combs Quarry, Ribblesdale: Unconformity between Silurian and Carboniferous rocks
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Why?
Late Caledonian-Variscan orogeny
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Post-Devonian intermission
https://fossilhub.org/geology-yorks-dales/
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Lower Carboniferous Basins and dales of limestones and shales
Ensom (2009) Two distinct regions:
Askrigg Block = Limestone dales
Craven, Harrogate, Bowland = Shale basins
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Up on the blocks Granite-buoyed high
LIMY: 3. Yoredale Group 2. Great Scar Limestone Gp 1. Ravenstonedale Group
Ensom (2009)
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Great Scar Limestone Group Malham Cove
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Great Scar Limestone Group
Waters et al. (2017)
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Limestones in a great scar
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Malham Formation
Gordale Member Cove Member
Horizontal = bedding; Vertical = jointing
Cove – lagoonal Gordale – marine shelf
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Waters et al. (2017)
Cracoe Limestone Formation Rugose coral Spiriferid brachiopod 20
Down in the basins Tectonic lows
Craven, Harrogate and Bowland basins: MUDDY 2. Craven Group 1. Bowland High Group
Ensom (2009)
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Blocks & Basins
Yorkshire Geol. Society: cross-section through Malham region
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Finding faults
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Mid-Carboniferous intermission
https://fossilhub.org/geology-yorks-dales/
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Yoredale Group Nossills
ap
Geological Map Data BGS © UKRI 2021. © Crown Copyright and Database Right 2021. Ordnance Survey (100025252).
Scale 1:10000 Mar 20, 2021 08:01 0 100 200 300 400 500 600 700 800 900 1000 m Liam Herringshaw University of York Cyclical rocksProgjection: Br itisinh Natio nalWensleydale Grid im 25 Di
Yoredale Cycles
Limestone – mudstone – sandstone – coal
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Yoredale limestone fossils Coral colonies
Siphonodendron
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Limestone fossils Sharks of Leyburn! Numerous teeth and spines found by Wm Horne
Sphenacanthus reconstructed
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Yoredale sandstones + siltstones Trace fossils
Parataenidium moniliformis
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Equatorial Yorkshire Climate and sea-level change in a glaciated world
Carboniferous palaeogeography, © Chris Scotese
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Late Carboniferous Sandstones and coal
Ensom (2009) 3. Pennine Coal Measures Group 2. Millstone Grit Group 1. Yoredale / Craven groups
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Millstone Grit Fluvial sandstones, Brimham Rocks
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Millstone Grit Enormous rivers eroding enormous mountains
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Pennine Coal Measures Truly 'Carboniferous' A few small outcrops around Dales
This should really be a photo of the Ingleton Coalfield!
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The post-Carboniferous
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Minerals & Mining
Galena – lead ore
Veins in fractures and faults, esp. in Swaledale & Grassington
Permian origin?
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Iced Dales
Anglian Glaciation 400,000 yrs ago
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Hyaenas, rhinos, bears Victoria Cave, near Settle (Ipswichian interglacial)
http://www.bbc.co.uk/news/science-environment-34486757
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The last Ice Age
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Kilnsey Crag
Baz Richardson, Flickr
Limestone spur, truncated by Wharfedale glacier 40
Drumlins
Ribblehead Drumlin Field Images © Durham University 41
Erratics
Norber © Val Vannett
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ß Read this!
https://fossilhub.org/ geology-yorks-dales/ Look out for these: Lost Beasts of the North
Hidden Horizons
Yorkshire Fossil Festival
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