Cenozoic evolution of the northern Vøring margin

Abstract

The northern Voring volcanic margin was initiated by late Campanian–Paleocene rifting, culminating with massive breakup-related igneous activity near the Paleocene-Eocene transition. Paleocene uplift of the central rift zone led to subaerial erosion and deposition in a restricted basin west of the Fles fault complex. The western source area was active toward the end of Eocene time. In the east, the low-relief land surface underwent modest relative uplift, which led to the construction of an early Oligocene delta system on the Trondelag platform. This event was followed by a period of margin subsidence and modest sedimentation until late Pliocene time. Although Miocene and early Pliocene biosiliceous hemipelagic sediments dominate on the outer margin, the influx of ice-rafted detritus records the climatic deterioration and the establishment of glaciers in late Miocene and early Pliocene time. Since ca. 2.6 Ma, ongoing epeirogenic uplift of Fennoscandia and the onset of Northern Hemisphere glaciation increased the erosion potential. A huge prograding wedge of glacial sediments was constructed from ca. 2.6 to 1.0 Ma, when the glacial mode changed from moderate, relatively stable icecaps to distinct glacial-interglacial cycles. The wedge overlies the base of the late Pliocene horizon, which marks pronounced changes in lithology and physical sediment properties, and corresponds to a distinct, regional velocity inversion. The differential glacial sediment load over unconsolidated and mobile biosiliceous oozes may have caused abundant small-offset faulting and diapirism in the western Voring basin.