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Survey Details for VLFGLGL863 - 2026-06-06

VLFGLGL863

Geological Landscape

Llanwit-St. Athan

Vale of Glamorgan

2005-01-13

  • Level 1: Lowland hills and valleys
  • Level 2: Dissected lowland plateau
  • Level 3: Lowland plateau

Monitoring

Q1 - Date of monitoring?

  • No Answer

Q1a - Monitoring undertaken by

  • No Answer

Q1b - Has this record been updated following monitoring work?

  • No Answer

Q1c - Change indicated by

  • No Answer

Q1d - What has changed?

  • No Answer

Q1e - Has the information ever been verified in the field?

  • No

Q2 - Does this area have a special or functional link with an adjacent area?

  • Yes
    • Part of dissected Lias plateau including VLFGLGL863 (Llanwit-St. Athan), VLFGLGL962 (Barry-Rhoose), VLFGLGL170 (Moulton), VLFGLGL 953 (Llanbethery) and VLFGLGL614 (Coed Hills).

Description

Q3 - If Classification is "Other", specify here

  • Empty value

Q4 - What is the geographical and topographical character of this area?

  • Broad, low, dissected coastal plateau underlain by Lias (Lower Jurassic) with steep sided valleys and short steep cwms cut into cliffs adjacent to the coast. Level plateau includes two airfields. Some periglacial deposits (head) in some valleys and cwms.

Q4a - Where bedrock dominated, what is the dominant bedrock type?

  • No Answer

Q4b - Where bedrock dominated, what is the age that characterises the aspect area?

  • No Answer

Q4c - Where bedrock dominated, what is the major rock lithogy (-ies)?

  • No Answer

Q4d - Where drift dominated, what is the dominant drift deposit?

  • No Answer

Q4e - Where drift dominated, what is the major sediment that characterises the area?

  • No Answer

Q5 - What is the characteristic Level 3 component of the area?

  • Lowland plateau

Q6 - Which of the following is a significant contributor to the geological character of the area?

  • Stratigraphic formation(s)
    • Blue Lias Formation (mainly 'normal' facies, minor marginal facies, dominated by Portkerry Member with minor St. Mary's Well Bay Member and Lavernock Shales Member ) (Hettangian-Lower Sinemurian, Lower Jurassic). Minor Carboniferous limestone incl.: Hunts Bay Oolite 'Group' (incl. Conelly Oolite [Holkerian] and Stormy Limestone [Holkerian]) and Oxwich Head Limestone [Asbian to ?Brigantian].
  • Superficial deposits
    • Head, alluvium, tufa.
  • Structural features
    • Faults
  • Active processes
    • Streams
  • Past processes
    • Periglacial

Q7 - What additional subsidiary Level 3 components are notable?

  • Undulating lowland hill terrain

Q8 - What Level 4 components are notable in this area?

  • Flood plain
  • Slope
  • Hill top
  • Scarp slope
  • Plateau
  • Spring
  • Urban / industrial development

Q9 - What active geological and geomorphological processes are significant in this area?

  • Streams
  • Empty value

Q10 - Are there components of significant hydrological importance?

  • Yes
    • Streams, springs.

Q11 - Are there any pedological processes that are significant in the area or have had a landscape forming effect?

  • Yes
    • Head deposits (periglacial)

Q12 - Is there current mineral extraction?

  • No

Q13 - Has there been mineral extraction in the past?

  • Yes
    • Building stone

Q14 - Are there SSSI/GCR sites here?

  • Yes
    • Monknash Coast SSSI (part) including Pleistocene and Holocene deposits of Cwm Nash.

Q15 - Are there geological SINC, 2nd tier, or RIGS sites in the area?

  • No

Condition

Q16 - Value

  • Outstanding

Q17 - Condition

  • Good
    • Dominantly rural area including Heritage Coast.

Q18 - Trend

  • Constant
    • Dominantly rural area including Heritage Coast.

Recommendations

Q19 - Existing management

  • Generally Appropriate

Q20 - Existing management remarks:

  • Dominantly rural area including Heritage Coast - development pressure therefore limited.

Q21 - Principal management recommendations

  • Ensure that no significant features or materials of geological or geomorphological significance are lost or damaged by implementing RIGS survey and site selection and temporary section recording. Maintain SSSI features in favourable condition by implementation of a management plan.

Q22 - Guideline

  • Medium Term
    • Ensure that no significant and potentially conservable features of geological or geomorphological significance are lost/damaged due to development; adopt a strategy of temporary exposure recording to ensure that significant geological features exposed in temporay excavations are recorded and samples conserved in recognised institutions as appropriate.
  • Immediate
    • Initiate RIGS (Regionally Important Geological Sites) survey and protect selected RIGS sites using Local Plan policies and constraint mapping.
  • Immediate
    • Implement management plan for SSSI to ensure maintenance of exposures and deposits in favourable condition.

Tolerance To Change

Q23 - Are there any significant threats to the current integrity and condition of the Earth Heritage features of the area?

  • Yes
    • In the absence of a RIGS survey of the area, potentially important geological and geomorphological sites are at risk from inadvertent damage by development or agricultural operations. No such net loss should be considered acceptable.

Aspect Area Boundary

Q24 - To what level was this information site-surveyed?

  • Level 3

Q25 - At 1:10,000, how much of the Aspect Area boundary is precise?

  • Most
    • Aspect Area boundaries surveyed at 1:25,000.

Q26 - What baseline information source was used for Aspect Area boundary mapping?

  • Other
    • British Geological Survey maps, aerial photographs, OS 1:25,000 Landranger topographical map.

Q27 - If OS Data was used, what was the scale?

  • 1:25,000

Q28 - What is the justification for the Aspect Area boundaries?

  • Boundary corresponds to cliff top or beach/land boundary to south, edge of river/flood plain systems to east and centrally and contact of 'normal' Lias with Carboniferous limestone-marginal Mesozoic facies to north.

Evaluation

Q29 - Evaluation Criteria: Research Value

  • Outstanding

Q29a - Evaluation Criteria: Educational Value

  • Moderate
    • No key sites with significant geological exposures.

Q30 - Evaluation Criteria: Historical Value

  • Moderate
    • Includes part of Monknash Coast SSSI with Pleistocene-Holocene features.

Q31 - Evaluation Criteria: Rarity / Uniqueness

  • High
    • Includes part of Monknash Coast SSSI with Pleistocene-Holocene features.

Q32 - Evaluation Criteria: Classic Example

  • Moderate
    • Includes part of Monknash Coast SSSI with Pleistocene-Holocene features.

Q33 - Evaluation Criteria: Overall Evaluation

  • Outstanding

Q34 - Justification of overall evaluation

  • Includes part of Monknash Coast SSSI with Pleistocene-Holocene features but with no other recorded sites with significant geological exposures.

Bibliography

Q35 - Sources and additional assessments

  • BRITISH GEOLOGICAL SURVEY 1989. Bridgend, 1:50,000 England and Wales Sheet 262 (including part Sheet 261 Sker Point) (Solid and Drift), British Geological Survey; CAMPBELL, S. & BOWEN, D.Q. 1989, Geological Conservation Review: Quaternary of Wales, NCC; GEORGE, T.N. 1970, British Regional Geology: South Wales (Third edition). HMSO; ORDNANCE SURVEY 1998. Explorer 151 (1:25,000); PERKINS, J.W., GAYER, R.A. & BAKER,J.W. 1997. Glamorgan Heritage Coast - a guide to its Geology, Glamorgan Heritage Coast; SIMMS, M.J., CHIDLAW, N., MORTON, N. & PAGE, K.N. 2004, Geological Conservation Review Series 30, JNCC; TRUEMAN, A.E. 1922, Proceedings of the Geologist's Association, London 33: 245-284; WARRINGTON, G. & IVIMEY-COOK, H. C. 1995, In: P. D. TAYLOR (ed.), Field Geology of the British Jurassic, Geological Society, London; WILSON, D., DAVIES, J.R., FLETCHER, C.J.N. & SMITH, M. 1990, Memoir for 1: 50, 000 geological sheet 261 and 262 (England and Wales), BGS.

Assessment

Q36 - Additional Assessments

  • None.

Q37 - Additional Comments

  • Additional Level 4 features include: Stream; Disused quarry.