Neogene inversion of the Central Graben and Ringkøbing-Fyn High, Denmark

Abstract

Inversion in the North Sea area and onshore Denmark is a well-known phenomenon and the main phase is interpreted to have occurred in the Cretaceous and early Cenozoic. This study demonstrates an important early Neogene inversion phase that resulted in the most distinct flexuring of the southern Danish Central Graben during the Cenozoic. Reactivation of structures on the Ringkøbing-Fyn High also took place during this inversion phase. Apatite fission track data confirm marked uplift of the marginal areas of the Fennoscandian Shield. The recognition of the inversion of the Ringkøbing-Fyn High is based on new high-resolution seismic data and has not been reported previously. Minor inversion pulses continued throughout the early and middle Miocene and ceased in the early late Miocene. The early Neogene inversion was the last major influence of the Alpine Orogeny in the Danish area. As a consequence of the early Neogene inversion, clastic sediments were flushed into the Norwegian–Danish Basin due to increased relief in the hinterland. The high sediment supply continued throughout the early Miocene despite changing climatic conditions from an overall cold temperate climate to a subtropical climate at the transition from the early Miocene to the middle Miocene. The high sediment yield, however, ceased due to marked subsidence in the middle–late Miocene following the last inversion pulse in the middle Miocene.