Norway's Geological National Monument, LEKA

The island Leka has been voted Norway’s National Geological Monument. The characteristic barren, reddish- yellow weathering rock belongs to the oceanic crust and was pushed up on land more than 400 million years ago.

Leka provides a deep cut through the oceanic lithosphere, where one can literally walk across the petrological and petrophysical Moho. Moreover, one can closely study the complexity of the mantle rocks and the transformation to ultramafic cumulates, completely exposed. The geology of the Leka Ophiolite is well published internationally and it is one of the key areas for identifying and understanding surpa-subduction zones ophiolites. In the complete ophiolite sequence found at Leka one can also experience to walk on MOHO (Mohorovicic discontinuity), the transition between the oceanic crust and the mantle.

Ophiolite complexes are remnants of ancient oceanic crust that once formed in the deep sea. Understanding of such deep-sea areas is central to science as these covers more than 60% of Earth’s surface. They are the most dynamic parts of the planet, and the volcanic crust that forms the deep-seafloor has developed within the last 200 million years of Earth 4.6 billion years long history. Formation of seafloor at spreading ridges and destruction of seafloor at subduction zones reshapes our planet continuously, and this process has a strong, long-term influence on climate and life on Earth. 

Foto: Anna Bergengren