Field Trip to the North Pennines of England & Hadrian’s Wall
Nent Valley above Alston and Nenthead
Leaders: Stuart Clarke (Keele University) and Colin Waters (University of Leicester)
A 2-day field trip to explore the late Visean – early Namurian Yoredale Group transition from the Alston Block to Northumberland Basin.
Saturday 3rd to Sunday 4th September 2022
(rearranged from September 2021)
This excursion will explore the Carboniferous geology of the North Pennines with special emphasis on the sedimentary succession that crosses the Visean / Namurian boundary. The overall aim is to compare and contrast this succession deposited on the Carboniferous high of the Alston Block (North Pennines; Figure 1) with strata of the same age deposited in the Carboniferous basin of the Northumberland Trough (Hadrian’s Wall and the A69 corridor), and to consider the sediments in the context of the evolving basin, sediment supply and sea level. There will also be ample opportunity to explore the structure of the North Pennines, its associated lead-zinc mineralisation and its mining history, as well as to understand the impact of the geology upon the upland landscape of the North Pennines.
All participants are requested to register for the event via the link above. We will then be able to provide suggestions for accommodation, detailed directions to the start locations, a Health and Safety risk assessment and fieldwork Code of Conduct, details on recommended clothing and PPE and further reading.
Cawfields Quarry, Northumberland
Programme
Saturday 3 rd September
Traverse through a late Brigantian to early Pendleian Yoredale succession on the Alston Block.
9.30 am Ashgill Bridge (CA9 3EU): NY 7586 4052. Parking for up to 5 cars is available at the side of the road on the bridge. Further parking is available along the road to the north. Minimising vehicles would be a good idea. No facilities. This section provides an unusual opportunity to visit a section behind a waterfall. The section comprises the late Brigantian Scar Limestone Member (Alston Formation) and underlying marine siltstone–interbeds typical of the Yoredale Group and represents the basal part of the succession to be visited.
Mid-morning we will then drive about 10 km northwards to visit Barneycraig Quarry (variably spelt ‘Barney Craig’ or ‘Barny Craig’) in the Coalcleugh (West Allen) Valley, with excellent exposure of the Great Limestone. The Great Limestone marks the top of the Alston Formation, and the Visean / Namurian boundary is in the sediment strata just below it. Sedimentary details of the Great Limestone and its relationship to underlying and overlying strata pose some interesting questions about changes in accommodation space, sediment supply and / or sea level during this time.
Time and access permitting, we will visit the section between the Little Limestone and Firestone Sandstone in the West Allen Valley to provide a framework for the late afternoon localities. We will finish at Nenthead, looking at exposures of the fluvial Firestone Sandstone, the youngest part of the Namurian succession to be visited and which shows the distinctions from the quartzitic marine sandstones of earlier in the day. Opportunity will also be provided to visit the extensive evidence of mining at this locality.
We expect to finish about 5pm.
Sunday 4th September
Visit the comparable late Brigantian to early Pendleian Yoredale succession in the Northumberland Trough and see the Great Whin Sill.
9.00 am Cawfields Quarry (NE49 9PJ): NY 7128 6657. Ample car parking with toilets. Opportunity to visit the Great Whin Sill.
We will then walk down the Haltwhistle Burn (easy path), returning via the same route. The total walking distance is 3.5km. Elevation change is minimal. We will visit essentially the same section visited on Saturday, but this time located in the Northumberland Trough and compare basin and block sedimentation over this time period.
The aim is to finish by about 4pm this day.