Читать книгу The Isle of Skye. Graded walks and scrambles throughout Skye, including the Cuillin онлайн

22 страница из 69

As with the rest of Britain and Europe, the geological history of Skye dips back to the Pre-Cambrian era of about 2500–3000 million years ago, although millions of years would elapse before Skye became an island. Quite what the landscape was like in those distant times is only guesswork, but on the basis of geological and topographical studies Skye can be divided into three distinct sections.

Heading for the Quiraing (Walk 6.4)

First, the southernmost part of the island, Sleat, is composed of Lewisian Gneiss, Torridonian sedimentary rocks, Moine Schists and Cambro-Ordovician sedimentary rocks. The already complex interrelationships of these basic rock types is further complicated by extensive thrusting and the transportation of large areas of all these rocks. The present landforms are the product of massive glaciation which over most of the island flowed westwards, but along the east coast flowed northwards.

North Skye, including Trotternish, Waternish and Duirinish, consists of a plateau-like topography punctuated by sea lochs, as at Snizort, Dunvegan and Bracadale. Here, Jurassic sedimentary rocks occur, capped by lavas and pyroclastic rocks from the Lower Tertiary period. Because these rocks dip at a shallow angle to the west, they give rise to steep scarp slopes on the east side, and it is quite easy to pick out the different and distinctive lava layers. One spectacular feature of these rocks is the incidence of landslipped material which developed during Quaternary times; the Storr and the Quiraing are by far the best examples.