SURVEYING FOR IMPORTANT GEOLOGICAL SITES IN THE SCOTTISH BORDERS
Rare and unusual rocks, minerals, fossils and landscapes need protection from damage, just like other natural ecosystems, so many volunteers throughout the world are doing what they can to protect their own geological environments. In the UK, important sites can be protected by being designated as Local Geodiversity Sites (LGS), which are special places chosen for their geological or geomorphological importance for future generations to enjoy and appreciate. By identifying LGS they can be protected from damaging activities and, where suitable, can be promoted for educational purposes, such as provision of information boards and leaflets. Although the Scottish Highlands and the Midland Valley of Scotland have been surveyed over several decades for LGS, the Scottish Borders has been a relatively neglected region until recently.
The most geologically significant sites in the Scottish Borders, such as Siccar Point on the Berwickshire coast and internationally important fossil sites along the Whiteadder Water and the River Tweed are already protected by their designation as geological Sites of Special Scientific Interest. However, the region has many other interesting rock types and landscapes, so, three years ago, two of us decided to start to start the process of surveying for geological sites, having done similar work for many years in West Yorkshire. We are active participants in a voluntary group, Lothian and Borders GeoConservation (LBGC), which is responsible for co-ordinating the designation of Local Geodiversity Sites in the Edinburgh, Lothian and Borders areas. LBGC has produced many printed and downloadable geological trails and leaflets, available from the Edinburgh Geological Society website. https://www.edinburghgeolsoc.org/publications/geoconservation-leaflets/
Surveying in the Scottish Borders was helped by the existence of two informal lists of sites from work done by the British Geological Survey in Scotland, one on greywacke localities in the west of the region and the second on sandstone quarries in the east. Searches of old OS maps available on the National Library of Scotland website turned up many ‘disused quarries’ and these were marked on 1:50,000 OS maps as sites to be explored. Several existing guide books and BGS sheet memoirs were extremely valuable and references to research papers were followed up. Overnight stays were necessary to visit potential sites in the more remote parts of the region, with the aim of driving along every valley in this sparsely populated area looking for exposures and quarries. About 250 sites were visited and photographed, some several times, with more than half of those fully surveyed and recorded.
After two years, it became clear that there were some exceptional sites, such as well-exposed examples of volcanic rocks or those which showed particularly clear sedimentary or metamorphic features. In the Ordovician and Silurian greywackes, the selection concentrated on sites which showed particularly good examples of geological structures. The attractive and prominent hills in the Scottish Borders are formed by a variety of igneous rocks, some of which are unusual in Scotland. Some landforms, such as Smailholm Tower, are accessible to the public and therefore have educational value so went to the top of the list.
Finding exposures of some rock types required considerable searching. The Lower Devonian Great Conglomerate underlies a considerable area of the Lammermuir Hills but was not quarried for building stone or aggregate, so we tramped across moorland areas looking for valleys which might expose the solid rock. The Upper Devonian and Carboniferous rocks of the lower Tweed valley are not well-exposed in agricultural areas and many quarries have been infilled or reused, although towns such as Kelso, Coldstream and Peebles display excellent examples of sandstones used for building.
Several sites have links with eminent geologists and are therefore significant localities for the history of geological research. The unconformity at Allars Mill, Jedburgh, was recorded by James Hutton and his contemporaries, the Eildon Hills and other volcanic landforms were studied by Lady Rachel McRobert, one of the first women to be elected as a Fellow of the Geological Society of London, and Charles Lapworth identified graptolite fossils in several quarries and upland valleys in the Ordovician and Silurian greywackes.
In autumn 2019, after three summers of surveying, 35 potential LGS were submitted to Scottish Borders Council (SBC) for inclusion in the Local Development Plan 2020, after we had written a short document to explain the guidelines used in the selection of potential LGS. As in most local authorities, staff members have little geological knowledge and very limited time, so surveyors and representatives of LBGC dealt directly with the Chief Planning Officer. We were provided with a base map on which we could delineate the boundaries of the LGS using GIS technology and help was provided by the Council’s technical staff. Site forms were completed for each potential LGS and we hope that the designated LGS will appear in the Local Development Plan 2020 and will be published on their website in due course.
Exploration of the region will continue, as it is possible that there are other sites with different features or with potential for further research, particularly in such a large and remote area. The good relationship we have with the local authority may enable management of some sites to take place if resources are available, in order to improve the accessibility of LGS which could be used for public enjoyment and learning. For the surveyors, who are familiar with the process of designating LGS, but were new to the Scottish Borders, the experience has been most enjoyable and, we hope, will be useful for future geoconservation.
Alison and Barry Tymon
Smailholm Tower – A basaltic
plug associated with lavas is one of
many prominent hills in the Tweed
valley, often topped by ancient tower
houses or monuments. In the
foreground are dipping sandstones of
Devonian/Carboniferous age into
which the early Carboniferous
igneous plug was intruded.
Hell’s Cleugh, Stobswood – A
rare exposure in the Lammermuir Hills of the Lower Devonian Great Conglomerate.
Eildon Hills, Melrose – The
footpath leads to Little Hill, a
basalt plug intruded into the
silicic sills of the Eildon Hills,
shown on Eildon Mid Hill to
the right. The Silurian
greywackes of the Borders
hills can be seen in the