Crosthwaite Parish Rooms Main Street Keswick CA12 5NN
DETAILS
The Garvellach Islands, Scotland
Outline: This talk examines how the concept of global glaciation in Late Precambrian (Neoproterozoic) time has evolved over the past century and more, culminating in the controversial theory of “Snowball Earth”. We take a brief look at the fieldwork we undertook in Svalbard and East Greenland in the 1970s and 1980s and then again in the 2010s. However, mostly we focus on our recent field investigations, led by Tony Spencer, on the remarkably well-preserved glacial strata on the Garvellach Islands and the Isle of Islay in western Scotland, and offer some insights into what might be appropriate modern analogues of that ancient glaciation. This work is currently being worked up for a Memoir of the Geological Society.
The presenter: Mike Hambrey is Emeritus Professor of Glaciology at Aberystwyth University, and resident of Threlkeld. He has published extensively on the topic of Neoproterozoic glaciation, particularly in the Arctic, but also has research interests in contemporary glaciology. His latest book, “Our Frozen Planet” is due to be published on 23rd October, and is a photographic journey through the world of snow and ice, with emphasis on climate change.
This excursion is based on the BGS publication “Geology in South West Scotland”
Edited P. Stone, 1996, and is an abbreviated version of Excursion 1 – Langholm and Canonbie.
iv We will be visiting locations 3, 4 and 6 from this excursion guide. There are full geology notes for the locations in this guide, available free online, which are not reproduced here.
Penton Linns
Logistics
Location 1
Meet 10.00 for 10.30 Charles Street Car Park, Langholm, Grid reference
NY 362 844, Postcode DG13 0AA
Langholm is on the A7 north of Carlisle, just over an hour’s drive from Keswick. From Keswick take the A66 east towards Penrith, join the M6 heading north at junction 40.
Exit the M6 at junction 44 and take the A7 north towards Longtown. Stay on the A7 past Longtown until you reach Langholm. Just after the narrow single lane section in
the town centre bear left and then turn left to reach the Charles Street car park.
Refreshments and toilets are available in Langholm town centre where there is also free short term disk parking. Pelosi’s Corner café is recommended for early arrivals
or those wanting a late breakfast.
We will assemble in Charles Street Car Park at 10.30 for the 2 mile loop walk to Skipper’s Bridge (there is no safe parking for a group of cars at Skipper’s Bridge, and
the riverside walk is pleasant).
At Skipper’s Bridge we will look at exposures of the Silurian greywacke basement, presumed to extend under the Northumberland-Solway Basin, the basin margin fault and early Carboniferous Birrenswark lavas from the extension-rifting phase – the birth of the basin.
We aim to return to Charles Street Car Park by 12.30 for the short drive to Penton
Bridge.
12.30 to 12.50 drive to Penton Bridge.
From Charles Street Car Park follow the one way system round to rejoin the A7 turning right to head south. At the traffic lights at Skippers Bridge turn left on the B6318 towards Penton. Follow the B6318 taking care to turn left at Claygate and then left and right at Harelaw where the road descends to the Liddel Water. There is
parking for 3-4 cars in the layby on the left before the bridge, and for several more cars on the roadside on the right past the bridge.
Location 2
Penton Bridge, Grid Reference NY 432 774, Postcode CA6 5QU. 12.50 to 15.50 we will explore this scenic geological SSSI to look at the Carboniferous Yoredale cycles, with fossiliferous limestones, mudstones, siltstones,
sandstones and coals. We will also explore the basin inversion fold and faults visible here. We will have lunch en route.We return to the cars at 15.50 for the short drive to Canonbie. 15.50 to 16.00 drive to Canonbie.
We return on the B6318 to Harelaw where we turn left on the B6357. We pass through Rowanburn, with it’s visible coal mining history. On entering Canonbie we
turn left at the signal-controlled bridge before crossing the River Esk signposted Canonbie churchyard. Follow this road towards the church, turning right at the
cemetery where there is parking for several cars. If this parking area is full there is more parking on the other side of the bridge in Canonbie at the village hall.
Location 3
Canonbie Church, Grid Reference NY 394 763, Postcode DG14
0RA. 16:00 to 17:00 we walk past ‘Dead Neuk’, scene of a tragic ferry accident in 1696 when 28 church-goers were drowned in a flood, and along the riverside. On the far
bank we can see Permian desert sandstones, the post-basin deposits.
We continue along the river bank to a small bluff where there is an exposure of late Carboniferous red-beds (the Canonbie Bridge sandstone). These are described in a
relatively recent BGS report “The stratigraphy and sedimentology of Upper Carboniferous Warwickshire Group red-bed facies in the Canonbie area of SW
Scotland” Jones and Holliday 2006.v These rocks are “probably typical of what covered most of northern England prior to late Carboniferous folding and uplift”
vi according to the British Regional Geology guide to Northern England, so represent the final deposits in the Northumberland-Solway Basin.
i https://doi.org/10.1016/0012-821X(78)90071-7
ii https://doi.org/10.1144/gsl.sp.1989.044.01.20
iii https://webapps.bgs.ac.uk/Memoirs/docs/B06816.html
iv https://earthwise.bgs.ac.uk/index.php/Geology_in_south-west_Scotland:_an_excursion_guide.
v https://nora.nerc.ac.uk/id/eprint/7191/1/IR06043.pdf
vi https://earthwise.bgs.ac.uk/index.php/Warwickshire_Group,_Carboniferous,_Northern_England
Crosthwaite Parish Rooms Main Street Keswick CA12 5NN
Speaker, David Boote
In 1788 James Hutton first recognised the importance of ‘deep time’ when studying a mid-late Devonian unconformity at Siccar Point, SE Scotland – shattering earlier suggestions of a 6000 year old earth by the Venerable Bede (3952BC), Johannes Keplar (3992 BC), Bishop Ussher (4004BC) and even Isaac Newton (~ 3992BC). The unconformity can be traced west across the western side of the Pennines and flanks of the Lake District Dome with coarse pebbly sandstones and conglomerates of late Devonian-basal Carboniferous age resting on highly deformed Lower Palaeozoic rocks. It marks the end of the Acadian (Caledonian) Orogeny, when mountain ranges deformed by the collision between Laurussia and Baltica-Avalonia continental plates, were worn down and transgressed by Carboniferous limestones and sands. The Lake District was subsequently blanketed by Late Palaeozoic and Mesozoic sediments interrupted by intermittent periods of exhumation, culminating with Cenozoic unroofing of the Lower Palaeozoic core exposed today.
A table has been booked at the Cassa Bella restaurant in Keswick for 6 people including the speaker before the lecture. We are now unable to book a large table together so if anyone wants to organise booking their own table there is an easy online booking system at www.casabellakeswick.co.uk The booking form has a ‘Notes’ box so it might be worth filling it in to ask for a table near the table that’s already booked for the Speaker. (Quote the Booking Reference R7NR4N for 25/09/24 and RPNR4B for 09/10/24 in the name of David Steele from 17.45pm) Depending on the positions of the tables we are given on the night it may hopefully work out that we can all chat together.
This excursion is based on the BGS publication “Geology in South West Scotland”
Edited P. Stone, 1996, and is an abbreviated version of Excursion 1 – Langholm and Canonbie.
iv We will be visiting locations 3, 4 and 6 from this excursion guide. There are full geology notes for the locations in this guide, available free online, which are not reproduced here.
Penton Linns
Logistics
Location 1
Meet 10.00 for 10.30 Charles Street Car Park, Langholm, Grid reference
NY 362 844, Postcode DG13 0AA
Langholm is on the A7 north of Carlisle, just over an hour’s drive from Keswick. From Keswick take the A66 east towards Penrith, join the M6 heading north at junction 40.
Exit the M6 at junction 44 and take the A7 north towards Longtown. Stay on the A7 past Longtown until you reach Langholm. Just after the narrow single lane section in
the town centre bear left and then turn left to reach the Charles Street car park.
Refreshments and toilets are available in Langholm town centre where there is also free short term disk parking. Pelosi’s Corner café is recommended for early arrivals
or those wanting a late breakfast.
We will assemble in Charles Street Car Park at 10.30 for the 2 mile loop walk to Skipper’s Bridge (there is no safe parking for a group of cars at Skipper’s Bridge, and
the riverside walk is pleasant).
At Skipper’s Bridge we will look at exposures of the Silurian greywacke basement, presumed to extend under the Northumberland-Solway Basin, the basin margin fault and early Carboniferous Birrenswark lavas from the extension-rifting phase – the birth of the basin.
We aim to return to Charles Street Car Park by 12.30 for the short drive to Penton
Bridge.
12.30 to 12.50 drive to Penton Bridge.
From Charles Street Car Park follow the one way system round to rejoin the A7 turning right to head south. At the traffic lights at Skippers Bridge turn left on the B6318 towards Penton. Follow the B6318 taking care to turn left at Claygate and then left and right at Harelaw where the road descends to the Liddel Water. There is
parking for 3-4 cars in the layby on the left before the bridge, and for several more cars on the roadside on the right past the bridge.
Location 2
Penton Bridge, Grid Reference NY 432 774, Postcode CA6 5QU. 12.50 to 15.50 we will explore this scenic geological SSSI to look at the Carboniferous Yoredale cycles, with fossiliferous limestones, mudstones, siltstones,
sandstones and coals. We will also explore the basin inversion fold and faults visible here. We will have lunch en route.We return to the cars at 15.50 for the short drive to Canonbie. 15.50 to 16.00 drive to Canonbie.
We return on the B6318 to Harelaw where we turn left on the B6357. We pass through Rowanburn, with it’s visible coal mining history. On entering Canonbie we
turn left at the signal-controlled bridge before crossing the River Esk signposted Canonbie churchyard. Follow this road towards the church, turning right at the
cemetery where there is parking for several cars. If this parking area is full there is more parking on the other side of the bridge in Canonbie at the village hall.
Location 3
Canonbie Church, Grid Reference NY 394 763, Postcode DG14
0RA. 16:00 to 17:00 we walk past ‘Dead Neuk’, scene of a tragic ferry accident in 1696 when 28 church-goers were drowned in a flood, and along the riverside. On the far
bank we can see Permian desert sandstones, the post-basin deposits.
We continue along the river bank to a small bluff where there is an exposure of late Carboniferous red-beds (the Canonbie Bridge sandstone). These are described in a
relatively recent BGS report “The stratigraphy and sedimentology of Upper Carboniferous Warwickshire Group red-bed facies in the Canonbie area of SW
Scotland” Jones and Holliday 2006.v These rocks are “probably typical of what covered most of northern England prior to late Carboniferous folding and uplift”
vi according to the British Regional Geology guide to Northern England, so represent the final deposits in the Northumberland-Solway Basin.
i https://doi.org/10.1016/0012-821X(78)90071-7
ii https://doi.org/10.1144/gsl.sp.1989.044.01.20
iii https://webapps.bgs.ac.uk/Memoirs/docs/B06816.html
iv https://earthwise.bgs.ac.uk/index.php/Geology_in_south-west_Scotland:_an_excursion_guide.
v https://nora.nerc.ac.uk/id/eprint/7191/1/IR06043.pdf
vi https://earthwise.bgs.ac.uk/index.php/Warwickshire_Group,_Carboniferous,_Northern_England
• Meet at the Blea Tarn National Trust Car Park (NT on map) (NY 2956
0432) to consolidate car use, discuss the weather and decide whether to go up the Crinkles or do this alternative to the Crinkle Crags Excursion in the event of low cloud.
• We will head up to the Three Shire Stone (M on map) for 10h00 and set off towards Teighton How (NY 27736 03273)
• None of the walking is on well defined paths and much is over open fellside, boggy in places. The descent from Blake Rigg to Blea Tarn is steep and only partly on a weakly defined path.
• The excursion is approximately 5km in length with ~300m of ascent and ~450m of descent.
• The excursion finishes at Bleaberry Knott, but if time allows other aspects of the area may be included on the way back to the NT car park at Blea Tarn
A table has been booked at the Cassa Bella restaurant in Keswick for 6 people including the speaker before the lecture. We are now unable to book a large table together so if anyone wants to organise booking their own table there is an easy online booking system at www.casabellakeswick.co.uk The booking form has a ‘Notes’ box so it might be worth filling it in to ask for a table near the table that’s already booked for the Speaker. (Quote the Booking Reference R7NR4N for 25/09/24 and RPNR4B for 09/10/24 in the name of David Steele from 17.45pm) Depending on the positions of the tables we are given on the night it may hopefully work out that we can all chat together.
Please register your interest to attend https://www.cumberland-geol-soc.org.uk/events/wrynose-to-blea-tarn-the-langdale-caldera-margin/ Wrynose to Blea Tarn The Langdale Caldera Margin[/event]
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