Trail 1: Unst Heritage Centre
Unst is an island in two halves. The The rocks to the east are oceanic, Begin your journey at the Unst Heritage Centre where an western side is made of rocks from forming an ophiolite. They began exhibition explains the geological story in detail. It is the former North Amercian as magma beneath the ocean, recommended that you visit this before heading out on the trails. continent. These are gneisses and which cooled and formed layers Outside the centre a geowall shows a cross section of the geology schists that were metamorphosed within oceanic crust. of Unst. (changed) by heat and pressure due Emplacement tilted the rocks so to burial before the continental that we can walk across all the collision took place. layers that are exposed on the surface today. Continental rocks Ophiolite rocks Younger metamorphic rocks
1 Westing gneiss 6 Serpentinite 11 Phyllite 6 7 8 9 10 11 Hascosay Slide Harzburgite 2 7 8a Blastomylonite (mantle rock) 1 2 1 3 4 Front of geowall 3 Pelitic schist 8 Dunite Moho Quartzite / Chromite within 4 8a 11 10 9 8 7 6 Semi-pelite dunite 3 4 3 Pyroxenite / 1 Intrusions 9 Wehrlite 5 2 1 Gabbro 5 Skaw Granite 10
Reverse of geowall
Directions Allow 1 hour to explore the Heritage Centre By car / bike: Take the A970 from Lerwick to Toft to catch the Yell ferry (29 miles). Follow A968 to the Unst Ferry at Gutcher (17 miles). Head north on A968 and follow signs to the Unst Heritage Centre (12 miles). 2km By bus: Daily buses to the North Isles operate from Lerwick Bus T2 Station. (An overnight stay in the North Isles would be needed if using T2 public transport). Heritage Centre T1 Interpretation Haroldswick T3 • Geology wall outside Unst Heritage Centre. • Exhibition within Unst Heritage Centre. T2 Baltasound Access Facilities
T4 Available within the Heritage Centre.
Cullivoe T4 1 2 3 4 5 6 Uyeasound T5
Gutcher © Hazel Prichard Hazel © 1 Central Unst - Wehrlite, pyroxenite and gabbro Hamars Ness 2 Saxa Vord - Continent 3 Keen of Hamar - Dunite 4 Clibberswick - Harzburgite Mid Yell Houbie 5 Balta - Gabbro 6 Ham Ness - Gabbro and dykes Ferry to mainland T6 Key parts of the ophiolite looking north from Muness