sea level



Voe - a long narrow sheltered bay

Voe is one of several place names, including Firth, Wick and Sound that describe the many coastal inlets on Shetland. All voes are valleys that have drowned by the rise of sea level in the post-glacial period. As such voes are akin to the rias of south-west England but whereas rias were originally river valleys most voes have been deepened by glacial erosion.

The Shetland voes vary greatly in size and form. Sullom and Aith Voe are ~12 km long and over 1 km wide in places. Ronas and Dales Voes have the steep sides characteristic of glacial valleys and here the glacial erosion has excavated well below present sea level. Many voes are smaller features however, of diverse form, with shallow sediment-filled bays and narrow, winding, rock-walled inlets.

The origins of the voes extend back to the preglacial valley system. During and probably also before the Quaternary the valley system became incised due to a combination of uplift of the islands and periodic drops in sea level to as low as -120 m when ice sheets formed
over North America and Europe. The Quaternary incision was only in small part due to river down cutting as most voes are floored in rock. Greater deepening was achieved by glacial erosion, aided by melt water streams. From bathymetry it is clear that tributary valleys on land converge first on voes which in turn join trunk valleys beneath the main sounds before extending on to the shelf.