Physical signatures of ice advance in a Younger Dryas ice-contact delta, Troms, northern Norway: implications for glacier-terminus history

The depositional history of an ice-contact delta in Sørfjorden has been reconstructed, based on two sections, 100 and 900 m long. Five major sedimentary facies have been distinguished within the delta's foreset, and their geometry and spatial organization have been mapped in the outcrops through the use of photographs. Facies 1 comprises chaotically bedded coarse clastics; facies 2 comprises sets of high-angle clinoforms; facies 3 comprises sets of low-angle sandy clinoforms; facies 4 comprises sets of hummocky sandy clinoforms and facies 5 comprises sets of low-angle to subhorizontal sandy and muddy clinoforms. The glacier advanced at least 500 m during the formation of the foreset sequence. Six minor halts during this advance are indicated. The study puts new constraints on the history of the Younger Dryas ice advance in the region, including local palaeogeography, ice-front dynamics and fjord-fill sediment stratigraphy.