OR/14/063 Site assessment - ELC 28: Tyne Estuary & Belhaven Bay

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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_28: Tyne Estuary & Belhaven Bay
Site Information
Location and Summary Description:

The Tyne Estuary & Belhaven Bay site is notable for a varied assemblage of dynamic coastal landforms located west of Dunbar. The main features are sand spits, intertidal sand flats, sand dunes, salt marshes, shore platforms, raised shorelines and a tsunami deposit.

National Grid Reference:

Mid-point: 364408, 679790
North-west end: 363636, 681113
South-east end: 366149, 678563

Site type:
  • Natural landform
  • Natural view
Site ownership: Not known Current use: Open country
Field surveyors: John Gordon Current geological designations: Part of the site lies in the Dunbar GCR site
Date visited: 2 December 2014 Other designations: Firth of Forth SSSI, SPA and Ramsar site; John Muir Country Park
Site Map
Figure 33    Tyne Estuary Map. The site boundary includes the landform assemblage of the modern estuary and bay as an integral coastal geomorphology unit. The adjacent bedrock and Quaternary site at Dunbar (ELC_4) is shown for reference (transparent grey area).
Site Description
Background

The site comprises a varied assemblage of coastal landforms, including sand spits, sand dunes, salt marshes, intertidal sand flats, raised shorelines and a tsunami deposit all developed in a highly dynamic environment (ELC_28 P1). Aspects of the coastal evolution, including its wider setting in the context of the deglaciation of the area, are described by Jackes (1973[1]), Rose (1980)[2], Davies et al. (1986)[3], Firth et al. (1997)[4] and Babtie Group ABP Research & Consultancy Ltd (2002). Jackes (1973)[1], Davies et al. (1986)[3] and Firth et al. (1997)[4] provide geomorphological maps of varying detail.

Quaternary Deposits and Landforms
Shore platforms and raised beaches
The east side of Belhaven Bay displays an assemblage of former shorelines represented by shore platforms and raised beach deposits. A shore platform in the present intertidal zone is cut across gently dipping Carboniferous strata and continues more extensively to the east (see ELC_4 Dunbar Shore). At the back of the present beach, there is a low cliff and a step up to a second (raised) shore platform overlain by a Holocene raised beach that is utilised by the Winterfield Golf Course (ELC_28 P2, P3). Inland to the east, the backing cliff of this platform rises to a higher glaciated shore platform. Good sections in the raised beach deposits reveal shelly sand and gravel deposits (ELC_28 P3).

However, some of the exposures have been covered by coastal defence works (concrete blocks and gabion baskets that are partly collapsing). Hall (2012)[5] notes that the coastal edge has retreated by some 45 m in this area since AD 1854, indicating significant coastal erosion of the soft bedrock cliff. On the Tyninghame shore, an extensive intertidal shore platform also fringes the bay north-east of Sandy Hirst towards St Baldred's Cradle. The platform here is extensively littered with glacial erratics (ELC_28 P4).

Sections in raised beach deposits and blown sand exposed by recent coastal erosion also occur along the south side of the Tyne Estuary near Hedderwick and along the lower part of the incised Hedderwick Burn (Davies et al., 1986[3]). The presence here of gravel layers with rip-up clasts of mud and broken shells may also represent deposits of the tsunami associated with the Holocene Storegga Slide (Hall, 2012[5]; Smith et al., 2012[6]); see also ELC_23 (Lochhouses).

Beach-dune-saltmarsh complexes
The site forms a large sediment sink with significant accumulations of sand in the extensive intertidal sandflats within the Tyne Estuary and the adjacent sand dune systems and sandy beaches (ELC_28 P1). The site is of particular interest for the two sand spits of Sandy Hirst and Spike Island (ELC_28 P1). Sandy Hirst extends south from the north shore of the estuary. It appears to have been a relatively stable feature since first recorded on Ordnance Survey maps in 1853 (Jackes, 1973[1]). On its west side, an extensive area of saltmarsh fringes the bay (ELC_28 P5). Saltmarsh is also present along the south-west margin of the site in front of Buist's Embankment.

Spike Island is a relatively recent recurved spit formed by coastal progradation through the growth and attachment of an offshore sandbank sometime after the 1940s (Jackes, 1973)[1]. A line of sand dunes has built up along the spit and an area of saltmarsh is developing on the former sandflats on its landward side (ELC_28 P1, P6). Inland of these saltings, a line of older dunes marks the former coastal edge. The southern part of the present coastal edge of Spike island is relatively low and appears relatively stable, whereas the seaward edge of the higher dunes towards the north end is cliffed and eroding (ELC_29 P7).

Additional Information
The wider geomorphological setting of the site comprises Lateglacial and Holocene raised beach deposits and a range of glacifluvial landforms and deposits that extend inland from the estuary into adjacent areas of predominantly agricultural land (Jackes, 1973[1]; Davies et al., 1986[3]; Firth et al., 1997[4]). These adjacent features have not been included here, but could be evaluated as part of a revised site assessment in the future.

Stratigraphy and Rock Types
Age: Carboniferous Formation: Ballagan Formation
Rock type: Sandstone, siltstone and dolomitic limestone
Assessment of Site: Access and Safety
Aspect Description
Road access and parking Access to the southern part of the site is from the A1 via the A1087 to Dunbar. There are public car parks and toilets at the John Muir Country Park access points at Belhaven and Linkfield. Access to the northern part of the site is from the A1 via the A199, A198 and the unclassified road (Limetree Walk) to the Tyninghame Links car park.
Safety of access No additional precautions beyond those normally associated with visiting a beach and dunes. Visitors should be aware of incoming tides if accessing the beach and intertidal flats and should note that the Belhaven bridge is not accessible at high tide.
Safety of exposure No special precautions are required.
Access There is good access on footpaths.
Current condition The condition is good.
Current conflicting activities None known.
Restricting conditions The active sand spit and intertidal areas are covered at high tide. Seasonal access restrictions may apply over parts of the site during the bird breeding season.
Nature of exposure Coastal.
Assessment of Site: Culture, Heritage & Economic Value
Aspect Description
Historic, archaeological & literary associations No known association.
Aesthetic landscape Coastal landscape.
History of Earth Sciences The John Muir Way passes the site.
Economic geology No known associations.
Assessment of Site: GeoScientific Merit
Rarity Quality Literature/Collections Primary Interest
Lithostratigraphy
Sedimentology
Igneous/Mineral/Metamorphic Geology
Structural Geology
Palaeontology
Geomorphology Regional Excellent X
Site Geoscientific Value

The Tyne Estuary & Belhaven Bay site displays an excellent suite of coastal landforms and sedimentary environments that demonstrate coastal evolution during the Quaternary, particularly during the latter part of the Holocene, and support a diversity of coastal habitats. There is significant potential for research on past and present processes of coastal evolution, as well as for education and public interpretation on coastal evolution and the links between geodiversity and biodiversity.
The Tyne Estuary & Belhaven Bay is an excellent regional example of an assemblage of dynamic coastal landforms and sedimentary environments.

Assessment of Site: Current site usage
Community The area is heavily used for recreation, including walking and birdwatching.
Education There is significant potential for education and public interpretation on coastal dynamics and evolution.
Assessment of Site: Fragility and potential use of the site
Fragility The site would be vulnerable to heavy trampling, off-road vehicle use, tree planting, tipping and coastal protection works.
Potential use School education and public interpretation addressing coastal dynamics and living with a dynamic landscape in the context of climate change and sea-level rise; research on modern coastal dynamics and sedimentary processes; monitoring coastal changes.
Geodiversity Summary
The site is an excellent example of a range of active coastal landforms and there is significant potential for research on coastal dynamics and developing its educational value and public interpretation through greater promotion of existing information.
Site Photos
Photo ELC_28 P1:    Satellite image showing the diversity of geomorphological features present.
Photo ELC_28 P2:    East side of Belhaven Bay, showing the intertidal shore platform, low backing cliff and raised shore platform with raised beach deposits on top now occupied by Winterfield Golf Course. The section in raised beach deposits in the foreground is shown in Photo 3. © John Gordon.
Photo ELC_28 P3:    Section in raised beach deposits resting on a raised shore platform planed across dipping mudstone and cementstone at Belhaven. © John Gordon.
Photo ELC_28 P4:    Intertidal shore platform littered with glacial erratics, north of Sandy Hirst.
© John Gordon.
Photo ELC_28 P5:    Saltmarsh on the west side of Sandy Hirst. © John Gordon.
Photo ELC_28 P6:    Saltmarsh development between Spike Island spit (left) and the former coastal edge marked by the line of sand dunes (right). © John Gordon.
Photo ELC_28 P7:    Present coastal edge of Spike Island. © John Gordon.

References[edit]

  1. 1.0 1.1 1.2 1.3 1.4 JACKES, M. 1973. Sites of geomorphological interest in East Lothian. Unpublished report to the Nature Conservancy Council, Edinburgh.
  2. ROSE, N. 1980. Beaches of Southeast Scotland. Department of Geography, University of Aberdeen, for the Countryside Commission for Scotland. Reprinted 2001 by Scottish National Heritage as a Commissioned Report. [Available online]
  3. 3.0 3.1 3.2 3.3 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).
  4. 4.0 4.1 4.2 FIRTH, C R, COLLINS, P E F, and SMITH, D E. 1997. Coastal processes and management of Scottish estuaries. IV — the Firth of Forth. Scottish Natural Heritage Review, No.87.
  5. 5.0 5.1 HALL, A. 2012. East Lothian Landscapes [online: http://www.landforms.eu/Lothian/]
  6. SMITH, D E, HUNT, N, FIRTH, C R, JORDAN, J T, FRETWELL, P T, HARMAN, M, MURDY, J, ORFORD, J D, and BURNSIDE, N G. 2012. Patterns of Holocene relative sea level change in the North of Britain and Ireland. Quaternary Science Reviews, 52, 58–76.