OR/14/063 Site assessment - ELC 25: Seacliff-Scoughall Shore

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Whitbread, K, Ellen, R, Callaghan, E, Gordon, J E, and Arkley, S. 2014. East Lothian geodiversity audit. British Geological Survey Internal Report, OR/14/063.
ELC_25: Seacliff-Scoughall Shore
Site Information
Location and Summary Description:

The site comprises an ~3 km stretch of coast 5 km east of North Berwick with importance for the study of modern processes of shore platform development by storm wave action and weathering.

National Grid Reference:

Mid-point: 361506, 684062
North-west end: 360255, 684864
South-east end: 362399, 682943

Site type:
  • Natural landform
  • Natural view
Site ownership: Partly Crown Current use: Open country; agricultural land
Field surveyors: John Gordon Current geological designations: Firth of Forth SSSI
Date visited: 24th October 2014 Other designations: Firth of Forth SPA and Ramsar site
Site Map
Figure 30    Seacliff-Scoughall Shore Location Map. The site boundary covers the landforms comprising shore platforms, backing cliffs, and postglacial raised beaches.
Site Description
Background

The site comprises a ~3 km stretch of coast with a well-developed intertidal shore platform located on a macro-tidal coast exposed to high wave energy from the north-east (ELC_25 P1, P4 and P6). The platform has an intermittent backing cliff and there are good examples of postglacial raised beaches and a higher-level shore platform. The site has been the focus of a detailed study by Hall (2011)[1].

Quaternary Deposits and Landforms
The intertidal shore platform has been developed by planation of Carboniferous sandstone, siltstone, calcareous mudstone and dolomitic limestone of the Ballagan Formation and associated volcanic intrusive rocks (Davies et al., 1986[2]; Hall, 2011[1]). The lithology and structure of the bedrock strongly influence the morphology of the platform, as elsewhere in East Lothian (e.g. Dunbar). The intertidal shore platform formation probably pre-dates the last glaciation.

A variety of blocks are scattered across the surface of the platform (ELC_25 P6). They include basalt and metamorphic glacial erratics washed out from till. In addition, there are quarried joint blocks sourced from the seaward edge of the platform by the force of the waves and collapsed blocks from the weathering and erosional undercutting of weaker sedimentary rock layers on the surface of the platform (ELC_25 P2, P3 and P5). The production and movement of these blocks illustrate the processes that are currently shaping the platform and highlight the importance of wave action and weathering. Wave currents during storms have moved the blocks away from their areas of production towards the land, as indicated by imbricated boulder trails (ELC_25 P2) and the dislodging of blocks off rock pedestals. In storms over the last 40–240 years, blocks as large as 9 m3 have been quarried from the platform’s seaward edge and boulders of >5 m3 have been moved landward over extensive areas of the platform, suggesting that wave current velocities in storms have probably reached 3–4 ms-1 in many places (Hall, 2011[1]).

The importance of differential weathering and erosion of weaker rocks on the surface of the platform is indicated by the presence of basalt and sandstone boulders resting on calcareous mudstone pedestals (ELC_25 P7). East of Scoughall, the backing cliff in red sandstone displays a good example of cavernous (taffoni) weathering forms (ELC_25 P8).

Inland, there are good examples of Holocene raised beaches at Seacliff and north of Scoughall, backed by a relict cliff. Between Seacliff and Scoughall a higher platform is present above the relict cliff.

Stratigraphy and Rock Types
Age: Carboniferous Formation: Ballagan Formation
Rock type: Sandstone, siltstone, calcareous mudstone and dolomitic limestone
Age: Carboniferous Formation: Southern Scotland Dinantian Plugs and Vents Suite
Rock type: Tuff and breccia
Assessment of Site: Access and Safety
Aspect Description
Road access and parking There is car parking at Seacliff Beach at the north of the site. Access is via a private road off the A198 east of North Berwick at Auldhame. There is a coin-operated entry barrier (£2.00 fee). There are toilets by the car park. Alternative access from the south is from Tyninghame Links car park.
Safety of access The site is accessed by walking along the beach from Seacliff at low tide. Alternatively, it is possible to walk north along Ravensheugh Sands from Tyninghame, but the Peffer Burn must be crossed. Visitors should be aware of tide times when planning a visit to avoid the risk of being cut off by incoming tides.
Safety of exposure Great care is required as the rocky shore platform is extremely slippery and there are loose rocks.
Access The site is accessible from the car park at Seacliff.
Current condition Good.
Current conflicting activities None.
Restricting conditions The main features are located in the intertidal area and therefore covered at high tide.
Nature of exposure Intertidal shore platform, cliff exposures.
Assessment of Site: Culture, Heritage & Economic Value
Aspect Description
Historic, archaeological & literary associations Tantallon Castle is located to the west of the site. JMW Turner made several sketches of the cliffs and shore at Tantallon Castle, including 'Tantallon Castle and Bass Rock from the East' (1818) sketched from The Gegan (see <http://www.tate.org.uk/art/artworks/turner-tantallon-castle-and-bass-rock-from-the-east-d13598>).
Aesthetic landscape Coastal landscape with views of the Bass Rock and Tantallon Castle.
History of Earth Sciences Not known.
Economic geology Not known.
Assessment of Site: GeoScientific Merit
Rarity Quality Literature/Collections Primary Interest
Lithostratigraphy
Sedimentology
Igneous/Mineral/Metamorphic Geology
Structural Geology
Palaeontology
Geomorphology Regional/National Excellent Hall, 2011[1], 2012[3] X
Site Geoscientific Value

Seacliff-Scoughall Shore is a good example of a shore platform, with excellent examples of rock weathering, erosional undercutting and block movement across the platform. The core value of the site lies in illustrating the combined role of modern wave processes and weathering on the erosion of an intertidal shore platform cut across a variety of rock types of different resistance on an exposed, macro-tidal coast. Representative examples of raised beaches and a higher shore platform also add to the interest and value of the site.
Seacliff-Scoughall Shore provides a variety of excellent examples of features related to shore platform development and is of regional to national importance. The site has significance for the study of modern processes of erosional coastal development.

Assessment of Site: Current site usage
Community Seacliff is a popular beach. Most visitors probably do not proceed beyond the end of the beach.
Education The site has good educational and research potential. However, safety of access is an issue for educational use. The area around The Gegan is most accessible for educational use (see <http://www.landforms.eu/Lothian/gegan.htm>)
Assessment of Site: Fragility and potential use of the site
Fragility The features are mainly formed in bedrock and are generally robust. They are dynamic and will evolve through natural processes of weathering and coastal erosion. The raised beached would be sensitive to development, waste tipping and tree planting.
Potential use School education, research and on-line interpretation.
Geodiversity Summary
Seacliff-Scoughall Shore is important for the study of modern processes of shore platform development by storm wave action and weathering. It has potential for both education and further research.
Site Photos
Photo ELC_25 P1:    Shore platform at The Gegan, Seacliff. © John Gordon.
Photo ELC_25 P2:    Boulder train on the shore platform at The Gegan. © John Gordon.
Photo ELC_25 P3:    Undercut collapsed blocks on the shore platform at The Gegan. © John Gordon.
Photo ELC_25 P4:    Shore platform south of Great Scar. © John Gordon.
Photo ELC_25 P5:    Undercut collapsed blocks on the shore platform south of Great Scar. © John Gordon.
Photo ELC_25 P6:    Shore platform with scattered boulders at Scoughall. © John Gordon.
Photo ELC_25 P7:    Perched boulders (glacial erratics) on the shore platform at Scoughall. © John Gordon.
Photo ELC_25 P8:    Cavernous (taffoni) weathering in sandstone cliff east of Seacliff. © John Gordon.

References

  1. 1.0 1.1 1.2 1.3 HALL, A M. 2011. Storm wave currents, boulder movement and shore platform development: A case study from East Lothian, Scotland. Marine Geology, 283, 98–105.
  2. DAVIES, A, MCADAM, A D, and CAMERON, I B. 1986. Geology of the Dunbar district. Memoir of the Geological Survey, 1:50 000 Sheet 33E and part of Sheet 41 (Scotland).
  3. HALL, A. 2012. East Lothian Landscapes [online: http://www.landforms.eu/Lothian/]