Apophyses (branches) of dark-coloured dolerite dykes in Kosterhavet National Park on Ramsö island in the Koster Islands in Sweden.
The dykes intruded between the Gothian orogeny (1.64 to 1.52 Ga) and the Sveconorwegian orogeny (1,2 to 0.9 Ga) at about 1.44 Ga.
Photo Copyright © Thomas Eliasson of Geological Survey of Sweden