Geology of a Neogene caldera cluster in Northeast Iceland – clues into rift zone architecture on a young Iceland

The Borgarfjorður-Loðmundarfjorður area in Northeast Iceland hosts an unusual volume of silicic rocks, as well as volcanic and sub-volcanic structures emplaced in the Miocene between 13.5 and 12.2 Ma. Here, we summarise the geology of the area and present a new geological map to summarise the current state of knowledge. We describe the prominent features of the volcanic centres, as well as regional marker horizons. Notably, the volume of silicic rocks, the distribution of eruptive centres, calderas, and intrusion swarms, as well as the interplay between regional flood basalts and silicic magmatism indicate a rift zone architecture different to that of the present day.