OR/15/017 Appendix 1 Field Trip Diary
|Tappin, D R, Long, D, Carter, G D O. 2015. Shetland Islands Field Trip May 2014 - Summary of Results. British Geological Survey Internal Report, OR/15/017.|
9th May 2015. Dave Tappin drives from Nottingham up to Edinburgh, stays overnight.
10th May 2015. Dave Tappin drives from Edinburgh to Aberdeen to catch the ferry to Lerwick in Shetland. The ferry stops at Kirkwall in Orkney where we pick up Dave Long. Overnight on the ferry (Watch the Eurovision Song Contest).
11th May 2015. Visit Sullom Voe and the Scatsta Voe site to introduce to the new visitors to Shetland the original Storegga tsunami deposit location. Small burn flows over the deposit forming a waterfall just down from new layby and information board. Tried to find the Dury Voe site of Burnie (1992) to the east, but this is now built over by the new road. Whilst on Mainland we examined the northernmost location, Isbister, for evidence of the Storegga event, bur unsuccessfully. The beach at Sand Voe is backed by thick till with no evidence for sand, and to landward is the Loch of Flugarth which might preserve the event (not previously sampled). DRT WPs 606–609.
12th May 2015. Visit Mid Yell Voe (DRT WPs 610-611). Observe a 3–4 m section of peat with one sand layer exposed and one at depth sampled in a gouge core; the sands are micaceous and organic rich, returning various 14C dates ranging from 8120 to 730 cal 14C BP. Birch wood is buried within peat above and below the sand layer. To the east, around a small headland is a second site with laminated sand and peat. Drive to the north end of Basta Voe to observe the thin (cm) sand bed dated at 1500BP (DRT WPs 612-615), then to Kirkibister (DRT WPs 616-618) to examine the section on the south side of the headland visited for the first time in 2013.
13th May 2015. Yell Island; visit the southern end Whale Firth to inspect the ?tsunami deposit discovered in 2013, then on to the north coast of Mid Yell Voe for further research on the sands there and then walk around the south coast of the Voe to visit the archaeological remains and a very thin sand in the peat cliff.
14th May 2015. Reconnaissance of Yell to search for tsunami sands on the coast (DRT WPs 616–654). At the north end of the island, at Gutcher, no evidence was found, even in coastal inlet (Loch of Gutcher) at the ferry terminal (HU549993, WPs 632–633). The coast along Bluemull Sound didn’t show promise either. It was noted that this area had had improvements to the agriculture quality of the land such that the peat blanket common elsewhere on Yell, was rare and that worked fields extended to the coast. At Breakon the extensive dunes appear to sit directly onto bedrock (HP528051, WPS 635–6) with no evidence of peat in which tsunami deposits are usually preserved. The sands here seem richer in carbonate than on other beaches. At the mouth of the Gloup Voe, at Kirks of Gloup, there is an extensive storm beach of cobbles and larger clasts (HP507050, WPs 637–8) — Wick of Whallerie. Here there is a thin till overlying bedrock on either side of the beach but no peat at the coast to preserve any potential tsunami deposit. There possibly was peat behind the storm beach but the ground rises up quickly and here and almost certainly the peat has been cut to produce pasture land. At the southern end of Gloup Voe (HP506030, WPs 639–640) there is some peat here, but much wind-blown sand. It was noted that the Gloup inlet has several ayres (tombolo or sand bank) at the northern end and at low tide the water is very shallow. The position of tracks on either side of the loch suggests that it is easily fordable. The inner part of the Voe appears much deeper. If a tsunami wave entered this inlet it is likely to have become very broken up at the entrance and a wave reaching the southern end would be quite confused. On the return to Mid Yell an examination of the coastal peat sequences along the southern shore of Basta Voe south of the peat cuttings around the new jetty for the fish farms (HU512980, WPS 6553–654) found no sand layer. The coastal peat cliffs are over a metre high and overlie thin till upon bedrock. As well as no evidence of sand within the peat there is no tree material evident, that may imply that the peat here is younger than mid Holocene although there is no younger sand present as seen at the head of Basta Voe.
15th May 2015. Strong winds and rain. Yell. Visit Loch of Valsetter on the east coast of Mid Yell to look for sand in the coastal peat. In the area of tombolo (HU534896) the coastal cliffs are formed of glacial deposits. Walked around southern edge of the Loch to examine the peat cliffs which are best approached from eastern side to avoid the river. At HU535889 (WPs 646–657) there is a peat cliff about 2m high which displays a sequence of:
- 1m of fibrous peat
- 70cm Peat with birch branches and logs up to 10cm diameter
- 20cm clayey peat,
but no sign of sand. Clays beneath the peat appear glacial. At approx. HU534889 (WP 648) between where two streams enter the Loch as marked on OS map there are laminated (<1cm) sands within the base of the peat. These are at the horizon in the peat with logs. The base of the interbedded laminated sediments is contorted, suggesting that they infill an irregular surface. Their upper surface is crosscut and overlain by darker, sand-free peat. This surface may represent a fallen or transported block of peat. Thin layers of micaceous sand can be seen towards the base of the peat cutting on eastern side of the western stream (of the two mentioned above). These are located within the peat with tree branches including pieces of Betula bark. At Salt Wick, approx. HU542891 (WP 650), there is a storm beach at the back of which there are a few patches of peat cliffs extending to the shoreline. There is no sign of old peat or sand, suggesting that cliff is rapidly eroding. Visited coastal sections at North Ay Wick (approx. HU537867, WP 651) and viewed from the car; these appeared to be composed of bedrock and glacial till, thus they are not promising for peat sections. Visited coastal sections at Otters Wick (approx. HU525856) and viewed from the car. The section appeared to comprise a storm beach overlying and backed by bedrock and glacial deposits, and thus not promising for peat preservation. Looked at coastal sections at Wick of Gossbrough (approx. HU530833) where there is an extensive area of cliffs of laminated, wind-blown sands showing cross cutting dunes. These extend along several hundred metres of the beach. Below the sands are bedrock and glacial deposits. Checked peats at top of beach at the ayre near Hamnavoe (approx. HU494802, WP 652), where there are large blocks/rafts of peat up to 1.5m high. The blocks have a sequence of peats including layers of Colluna (heather) within smoother sphagnum moss peat.
Checked site near fish farm at mouth of Aris Dale River (approx. HU486808, WPs 653 and 654), where a peat cliff is 1–2m high overlies sands and gravels. There are a few wisps of sand within the basal few centimetres of the pat sequence; at one location there is a curious horizon of large schistose boulders about 60cm above the base of the peat.
16th May 2015. Mainland. Examination of various inlets on the eastern side of Mainland where peat is notably absent; locations visited include Colla Firth, Swining Voe, Vidlin Firth, Dury Voe, Loch of Benston and Garth Loch. There are no coastal peat cliffs, but inland, peat sequences except at Dury Voe, but peat might be found through coring (as at Loch of Benston.
17th May 2015. Gareth Carter arrives, picked up at Sumburgh Airport. Yell. Visit the NW end of the Whale Firth site at the south end of the Loch where there is a separate laminated sand layer within the peat, located within the zone of peat wood fragments. The sand is located downslope of an area of hummocky peat, which appears to form the distal end of a debris flow.
18th May 2015. Dave Long departs – taken to Sumburgh Airport. Observe on route the dramatic landscape of the Channerwick peat slide. Basta Voe. Visit the site of the thin sand.
19th May 2015. Mid Yell. Work on the north side of the Voe, examining the peat and sand, gouge core inland of the main section above the ?archaeological site. Then carry out the gouge core traverse between Whale Firth and Mid Yell Voe; 9 sites cored, but no tsunami sand found.
20th May 2015. Visit Fetlar to investigate for tsunami sands; firstly to the south coast where a tombolo divides Papil Water from the Wick of Triesta; here we find a sandy beach at the rear of which is boulder storm beach. There is no peat in the 3–4 metres high coastal cliffs and Aeolian sand overlies bedrock of Old Red Volcanics. At Funzie Bay on the west coast, there is a storm beach of cobbles and boulders, with the bedrock geology here is of metamorphosed sediments of the ophiolite complex.
21st May 2015. To Unst, to carry out a reconnaissance survey of the coast for peat; the weather is very wet and visibility low. We first visit the Heritage Centre at Haroldswick which provides a cup of coffee and some interesting insight into the history and development of the island, especially the relationship between the relationship between peat development and bedrock; peat forms mainly on till or on siliceous rocks such as Old Red Sandstones and metamorphic schists and gneisses. The large areas of serpentine of the ophiolite complex forming Unst and Fetlar produce a very poor soil able to support few plants and hill peat never formed on them. We then visited Nor Wick in the northeast, where we find no peat as the bedrock is ophiolite. At Burra Firth we find that there is bedrock at the coast and sand dunes. Inland at Quoys there is mainly pastureland; at the southern end of the Loch there is a similar landscape. Travelling south to the Ham of Muness we find a bolder beach and pastureland at the coast resting on a thin till, but again with no peat. At Sand Wick the till at the coast is thicker, the beach is sandier, but again no peat is present. On the southwest coast we visit Lunda Wick Bay by St Olafs Church where there is a sandy beach, with storm cobbles at the rear fronting low cliffs of thin till overlying Old Red Sandstone.
22nd May 2015. Yell. Back to Whale Firth for Russian Coring of the tsunamis and at the south end of the Firth. Then to the east end of the core traverse to Mid Yell Voe, to core at Site 9.
23rd May 2015. Packing up before heading off home.
24th May 2015. Depart Yell. Coffee at the Wee Haas, then onto the ferry to Mainland. Detour to Eshaness Headland to look at the storm deposits on the cliffs; then to Lerwick to catch the ferry to Aberdeen; overnight on the ferry (watch the European Champions Cup final).
25th May 2015. Drive Aberdeen to Edinburgh to drop Gareth Carter off, then Dave Tappin drives home to Nottingham.