|
|
The 2011 Field Visit Reports booklet - containing full reports for each excursion of the 2011 field calendar - can be viewed using the link on the right. The file size is 2.71 MB and the format is pdf.
Please note: The field reports are personal accounts of LGA field excursions, written by a members of the LGA, recording their impressions of the event. They are intended as a summary of the geology of the area visited.
The routes described may not be suitable for use by individuals and/or groups and do not necessarily follow an established path or public right of way.
|
Excursion Details
|
|
Saturday 14th May 2011 — Millfield Gill, Askrigg, Wensleydale
|
Leader: Dr John Varker, University of Leeds (retired).
Purpose:
To examine two or three cyclothems in the classic location of Wensleydale (Yoredale-Uredale), which represents the stratotype
location for the Wensleydale Group (Dinantian). To discuss the mechanism of formation of the cyclothems and their position
within the regional stratigraphy. To draw sketch sedimentary logs to illustrate the sequence, depending upon circumstances.
The cyclothems at this location are represented by a series of spectacular waterfalls almost as high as Hardraw Force itself.
To see and discuss distant views of some unsurpassed glacial depositional topography in the valley floor east of Hawes.
Geology: Carboniferous, Quaternary.
Maps and references:
OS Outdoor Leisure Series 30 1:25,000.
BGS 1:50,000 Kirkby Stephen Sheet 40 Solid and Drift edition.
Rayner, D.H. and Hemmingway, J.E. (eds). (1974) The Geology and Mineral Resources of Yorkshire Leeds. YGS.
A very old and certainly out of date account of the actual route can be found in
Kendall and Wroot "The Geology of Yorkshire", p. 839 under the heading of Mill Gill Askrigg.
This is the same river (Gill) that changes its name several times in a short length.
|
|
Thursday 9th June 2011 — Otley Chevin Geology Trail
|
Leader: Alison Tymon, West Yorkshire Geology Trust.
Purpose:
A walk of about 3 km following the Otley Chevin Geology Trail leaflet to see tidal laminites, quarry faces with many sandstone
and grit sedimentary structures, coal seam with fireclay, plant fossils, landslip scars and excellent views over Wharfedale and Airedale.
Geology: Carboniferous, Quaternary.
Maps and references:
Chevin Forest Park Geology Trail leaflet - free copies will be provided.
|
|
Sunday 19th June 2011 — Humberhead Levels & N Linconshire
|
Leader: Prof Mark Bateman, Sheffield University, and Dr Paul Buckland.
Purpose:
To visit the Humberhead Levels beginning at Tudworth and then Lindholme to look at new exposures in the terminal deposits of the
Last Glacial Maximum. Thereafter across the Levels to N Lincs, ending at Alkborough and Julian's Bower, overlooking the confluence of the Trent and Ouse.
There remains considerable dispute over the limits of the last glaciation in the Vale of York. The limit, long held at the York-Escrick moraines,
was overturned by the work of Geoff Gaunt, published in PYGS in 1976, who pointed to a discontinuous, slightly sinuous ridge running southwards
from the Snaith-Cowick ridge through Thorne to Tudworth and Lindholme and on to Wroot, south of Hatfield Moors. Rich in Magnesian Limestone pebbles,
he was able to correlate this with a small patch of similar gravel on the Isle of Axholme at High Burnham. On the basis of borehole records,
Tony Cooper and colleagues at BGS have recently disputed this line and returned the limit to the Escrick line. Neither had the advantage of
meaningful open exposures, but a quirk of fate, or rather a series of trial pits for an aborted gravel extraction enterprise, has provides
a series of exposures at Lindholme, an island in the middle of the National Nature Reserve on Hatfield Moors. These have recently been studied
by an Edinburgh/Sheffield MSc student, Robert Friend, and his results add considerably to the complexity of the story. Gaunt correlated the
deposits with a short episode in the history of high level (~30 m) Lake Humber, the existence of which has been doubted by others. The diversion
of the A1 around Ferrybridge, however, provided sections in deposits previously mapped by Edwards as shoreline deposits of this lake and these
have been conclusively dated by OSL to the Last Glacial Maximum. Somewhat older dates have now been obtained by the same technique from Lindholme
and these again conclusively show the deposits to belong to the same episode, and just to emphasise this, a flint implement picked up on the floor
of one of the trial pits is clearly Upper Palaeolithic. Gaunt's line seems therefore clearly vindicated but there are more problems. The site
lies considerably lower than the ~7 m shoreline of the later low level Lake Humber, whose deposits have been examined in gravel pits at Finningley,
a few miles to the south and archaeological excavations at Sandtoft to the north. There are no low level lake deposits at Lindholme, although
the ephemeral high level lake might be there. Flow tills and in situ frost-shattered erratics, all of Palaeozoics, rather Mesozoics (if we ignore
the Sherwood Sandstone that is), indicate the proximity of Pennine ice but how proximate? Is the structure terminal moraine (a term studiously
avoided by Gaunt), esker, or related to riverine flow over a deep frozen lake and if the Lindholme-Wroot ridge is not a terminal moraine where
exactly was the ice front? All contributions to the discussion will be gratefully received.
Geology: Quaternary.
Maps and references:
Landranger series maps 111 and 112.
BGS sheets: 71, 79, 80 and 88.
Bateman, M.D. (1998). The origin and age of coversand in North Lincolnshire, UK. Permafrost and Periglacial Processes 9: 313-325.
Bateman, M.D., Buckland, P.C., Frederick, C.D. & Whitehouse, N.J. (2001). The Quaternary of East Yorkshire and North Lincolnshire. Field Guide. London, Quaternary Research Association.
Bateman, M.D., Buckland, P.C., Chase, B., Frederick, C.D. & Gaunt, G.D. (2008). The Late-Devensian pro-glacial Lake Humber: new evidence from littoral deposits at Ferrybridge, Yorkshire, England. Boreas 37: 195-210.
Ford, J.R., Cooper, A.H., Price, S.J., Gibson, A.D., Pharoah, T.C. & Kessler, H. (2008). Geology of the Selby District - a brief explanation of the geological map. 1:50,000 sheet 71 Selby (England and Wales). Nottingham , British Geological Survey.
Gaunt, G.D. (1976). The Devensian maximum ice limit in the Vale of York. Proceedings of the Yorkshire Geological Society 40: 631-637.
Gaunt, G.D. (1994). Geology of the country around Goole, Doncaster and the Isle of Axholme. Memoir of the British Geological Survey Sheets 79 and 88 (England and Wales). London , HMSO.
Gaunt, G.D., Buckland, P.C. & Bateman, M.D. (2006). The geological background to the development and demise of a wetland - the Quaternary history of the Humberhead Levels. Yorkshire Naturalists' Union Bulletin 45 Suppl.: 6-46.
Gaunt, G.D., Fletcher, T.P. & Wood, C.J. (1992). Geology of the country around Kingston upon Hull and Brigg. Memoir of the Geological Survey of England and Wales, Sheets 80 and 89. London, HMSO.
Gaunt, G.D., Jarvis, R.A. & Matthews, B. (1971). The Late Weichselian sequence in the Vale of York. Proceedings of the Yorkshire Geological Society 38: 281-284.
Murton, D.K., Pawley, S.M. & Murton, J.B. (2009). Sedimentology and luminescence ages of Glacial Lake Humber deposits in the central Vale of York. Proceedings of the Geologists' Association 120: 209-222.
Straw, A. (2002). The Late Devensian ice limit in the Humberhead area - a reappraisal. Quaternary Newsletter 97: 1-10.
|
|
Sunday 3rd July 2011 — Building Stones of Central Leeds
|
Leader: Murray Mitchell, BGS (retired).
Purpose:
To examine building stones in the Corn Exchange, Commercial Street, Albion Street, St John's Centre, The Light, St Ann's Cathedral and the northern part of Park Row.
Maps and references:
The Building Stone Heritage of Leeds, Francis Dimes & Murray Mitchell, 2nd Edition published 2006.
|
|
Sunday 17th July 2011 — Black Rocks, Wirksworth area, Derbyshire
|
Leader: Ian Chisholm, BGS (retired).
Purpose:
- Ashover Grit: syndepositional gravitational slides, demonstrated by panoramic views and a visit to exposures.
- Carboniferous Limestone: view into a large quarry; and later a panoramic view of the structure surrounding
the Bonsall Fault, an inverted syndepositional tectonic structure.
- National Stone Centre: for car parking, toilets and cafe at the end of the trip.
Geology: Carboniferous.
Maps and references:
OS 50K sheet 119 (Buxton & Matlock).
BGS 50K sheets 112 & 125 (NB: these are out of date, showing a tectonic interpretation of the slide areas).
Article in Yorkshire Geological Society Transactions on Ashover Grit by Chisholm & Waters (2011).
|
|
Saturday 17th September 2011 — Thornwick Bay, N Landing and S Landing
|
Joint field meeting with Hull Geological Society.
Leader: Mike Horne, Hull Geological Society.
Purpose:
To examine the Burnham Formation Chalk of North Landing and Thornwick Bay (morning) and the Flamborough Formation Chalk and Quaternary Deposits of South Landing (afternoon).
Geology: Cretaceous, Quaternary.
Maps and references:
OS 1:25,000 Scarborough, Bridlington and Flamborough Head. No. 301.
Yorkshire Rocks and Landscape, Ed: Colin Scrutton & John Powell, YGS. pp 192-199.
The Yorkshire Coast, Ed: PF Rawson & JK Wright, GA Guide No.34. Itinerary XI Thornwick Bay and North Landing;
Itinerary XIII South Landing to Sewerby; Itinerary XII Flamborough Head.
Whitham F. (1991). The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham Formations north of the Humber, north east England.
Proceedings of the Yorkshire Geological Society 48, 227-254.
Whitham F. (1993). The Stratigraphy of the Upper Cretaceous Flamborough Chalk Formation, North of the Humber, north-east England.
Proceedings of the Yorkshire Geological Society 49, 235-238.
|
|
Fri 30th Sept - Mon 3rd Oct 2011 — Residential Weekend: Grange-over-Sands
|
|
|
