Why the Rommaeno Complex? 

What makes the complex exceptional? The Rommaeno Complex of northwestern Finnish Lapland preserves some of the oldest continental crust in northern Europe, with rocks dating back to around 3.2 billion years. The complex is exposed adjacent to the Caledonian nappes at the level of the Great Unconformity providing a rare opportunity to investigate the composition and architecture of the uppermost preserved Archaean crust.

Why does this matter scientifically? Exposure at the level of the Great Unconformity provides a rare opportunity to investigate the composition and architecture of the uppermost preserved Archaean continental crust. By integrating structural geology, petrology, geochemistry and geochronology, these ancient crustal records can be used to reconstruct the processes through which partial melting of basalt generated the TTG magmas that built Earth's earliest continental crust.