The Lone Shieling

The route known as the Cabot Trail in the Cape Breton Highlands National Park cuts right through some of the oldest rocks in the world as it passes round the northern perimeter of the park between North Mountain and the Grande Anse Valley. These rocks belong to the Blair River Inlier  and are up to one and a half billion years old (Donahoe et al. 2005).  They were pushed up from deep down in the earth’s crust by two major fault lines during the Appalachian mounting building episode so that they now lie adjacent to much younger rocks. The road is steep and winding as it passes through the territory, affording no opportunity to get a closer look at this isolated portion of the Canadian Shield and the ancient supercontinent of Rodinia.

It is, however, possible to pull off the road at a site called The Lone Shieling where a replica shepherd’s hut has been built to commemorate the Scottish heritage of the people who first settled the area after being expelled from the highlands of the Isle of Skye. Contained within the walls of this building and its boundary wall are local rocks, some of which come from the nearby Blair River Inlier. They include pink-grey granulite, banded quartz-feldspar gneiss, and also igneous rocks like the white anorthosite, and dark pink syenite that have been zircon dated to 1,100 to 980 million years ago when they intruded into even older rocks that formed about 1,500 million years ago (Hickman Hild and Barr 2015).

The Lone Shieling shepherd’s hut lies within the only accessible part of an undisturbed 4,000 acres of protected hardwood forest, the largest of its kind in the Canadian Maritimes, and marking the northern limit of growth for many of its plant species. Within the sheltered Grande Anse River Valley 97% of the trees occupying the rich moist soil of lower slopes are deciduous sugar maples (some are 350 years old and 25 metres high) with lower numbers of other species like elm, red spruce, hemlock, yellow birch, white ash, striped maple, red oak. White spruce grows on the stony river banks. Wild flowers, twenty species of ferns, and millions of hardy sugar maple seedlings cover the forest floor. Bracket fungi colonise old wood of trees left to fall. Melting snow from mountains to the south floods the river each year and strips soil from the river bed while bringing down rocks of all kinds. Angular stones of a multiplicity of types, colours, textures, patterns, and geological periods are strewn over the river bed.

REFERENCES

Atlantic Geoscience Society (2001) The Last Billion Years – A Geological History of the Maritime Provinces of Canada, Atlantic Geoscience Society Special Publication No. 15, Nimbus Publishing, ISBN 1-55109-351-0.

Canadian Confederation of Earth Sciences (2014) Four Billion Years and Counting- Canada’s Geological Heritage, Nimbus Publishing, pp 93-97, ISBN 978-1-55109-996-5.

Donohoe, H. V. Jnr, White, C. E., Raeside, R. P. and Fisher, B. E, (2005) Geological Highway Map of Nova Scotia, Third Edition. Atlantic Geoscience Society Special Publication #1.

Hickman Hild, M. and Barr, S. M. (2015) Geology of Nova Scotia, A Field Guide, Touring through time at 48 scenic sites, Boulder Publications, Portugal Cove-St. Philip’s, Newfoundland and Labrador. ISBN 978-1-927099-43-8, pp 30-35.

http://www.pc.gc.ca/eng/pn-np/ns/cbreton/natcul/natcul1/b/i.aspx