cliff-top storm deposits

Near-vertical cliff face >15 m high

 

The Nev

Significance: exceptional cliff scenery and dramatic cliff-top storm deposits

The magnificent high-level storm beach at The Nev in Aikerness was probably first noted and photographed by Wilson et al. in 1935. They described a continuous ridge of angular blocks of flagstone up to 3 m across and 0.3 m in thickness situated on top of a vertical cliff up to 21 m above sea level. The ridge is about 400 m long, 30 m wide and up to 5 m in height. Wilson et al. recognised the origins of the material as a storm deposit and clearly understood that the ridge contained elements which are contemporary and others of more ancient origin. 

The cliff at The Nev is >15 m high and slopes at 75 above a short rock platform at the cliff foot. On top of the cliff is a rock platform which slopes inland at about 4 for 70 m. The front surface is largely clear of debris and shows fresh scars from joint block removal. Several  scars are not apparent on the photograph of Wilson et al. (1935) . To the rear of the platform lie fresh angular blocks up to 1.5 m across and possibly derived from the scars to seaward. Beyond this lies the storm boulder beach, which rests on the weathered surface of the flagstones. It is about 4 m in height and shows large imbricate blocks on its surface, of which the largest is 3 m across. The imbrication of the boulders lies between 250 and 300, implying transport by waves from WSW to WNW.

The ridge front shows both fresh and patinated blocks and comparison with the Memoir photograph suggest that there has been little recession of the ridge since 1935. The ridge top and rear show blocks up to 1.5 m across partly buried by turf and with a cover of lichen, indicating that the ridge is mainly composed of relatively old debris. Some 6 m inland of the main ridge is a low ridge, 0.5 m high, composed of fresh, angular cobbles, which appear to represent the inland limit of recent storm-washed debris. Large blocks up to 1 m across protrude through the turf to the rear of the main storm ridge and appear to relate to wash-over from extreme storm events.

To the north, the storm ridges are more subdued and weathered. There is no washed cliff-top platform to seaward and the ridges appear to be fossil features, soon to be destroyed by cliff retreat. Sections in a track along the cliff top show 1-1.5 m of weathered breccia in which small pebbles are broken down to a slightly silty sand. It is unclear how old this weathering is but it suggests that these storm deposits predate the last few centuries, at least.

Recent observations by Woodman-Smith (2004) have confirmed continuing activity. He records sockets on the platform and cliff edge that remain angular and lichen-free, implying recent block removal. Impact marks also occur on the ramp where large boulders have been dropped by waves with considerable force. It is estimated on the basis of edge rounding that the oldest deposits were emplaced 300 years ago.