Villians of Hamnavoe

Significance: the Villians of Hamnavoe display several km of coastline shaped by storm waves. The cliff top storm deposits are the most extensive in Britain and match those on the Aran Islands in Eire

key sites   grind of the navir   south head    cliff top storm deposits  Streetmap extract   SSSI                  

Villians of Hamnavoe, looking N to South Head 1995                                              Images from January 2012 by Ian Napier

The cliff profile shows along this coast varies with structure. The Devonian tuffs and andesite lavas generally form a cliff top at around 20 m with a  ramp that slopes gently inland. At South Head the flows are inclined to give a sequence of tilted benches. Water depths offshore reach depths of 50 m beyond fringing steps indicated by reefs.

Cliff top embayment, with gravel beach and imbricate blocks. The storms of the early nineties overturned and moved many of these blocks but the thick lichen cover shows that they were reworked from earlier storms

The lower part of the cliff may be near vertical or ramp like according to the dip of the tuff. The upper part of the cliff and the backing ramp show a zone washed by waves and largely free of blocks. The rear of the ramp is littered with large blocks and rest against a low bluff cut in till and older cliff top storm deposits, a mix of wave and air throw debris. The turf extends for several hundred metres to the base of the hill slope. Large, lichen-covered blocks can be seen here. Toward South Head there is a large embayment on the cliff top with a gravel and sand beach.

Observations in 1995 showed that the 1/1/1992 and 17/1/93 storms had mobilised material across the whole width of the platform and turned over blocks at the turf edge. The cliff top at South Head was scoured to a height of 40 m OD. Storm wave water overtopped parts of the cliff and flowed by spillways back to the ocean.

These storms were amongst the most severe of the last century but waves only reached the turf edge. Earlier storms carried blocks much further inland, although not to higher altitudes. Preliminary dating suggests that the cliff top storm deposits at Villians of Hamnavoe began to accumulate before 800 AD.

The image sequence gives a view from Whalwick Taing from N-S.