Black beach

| Jon Arne Øverland and Terje Solbakk (photo)

Black beach

Parts of the Kvalbein beach in southern Rogaland, the county embracing Stavanger, change character completely in winters with much strong wind.

Its normal covering of pale quartz sand gives way to dark, almost black, grains which consist largely of magnetite and ilmenite plus a little zircon.

Weight differences mean that wind and waves carry the quartz  out to sea, leaving behind the dark minerals. But this process is cyclical. Changes in wind direction and less intensive wave action in the summer months usually bring all the pale sand back.

Ilmenite – an important industrial mineral – and magnetite are common in Rogaland’s anorthosite province, which extends west roughly to Kvalbein.

Sokndal lies centrally in this province, and the Titania company operates a big opencast ilmenite mine there.

Topics: Geology