SEDIMENTOLOGY AND DEPOSITIONAL HISTORY OF AN EARLY HOLOCENE ICE-CONTACT SUBMARINE FAN - THE EGGE-LYNGAS END-MORAINE, SOUTHERN NORWAY

The 140-m-thick 'end-moraine' ridge at Egge-Lyngas comprises a lower m ud overlain by a 100-m-thick gravelly succession representing an ice-c ontact submarine fan formed around 9800 years BP. Outcrop studies from the upper 80 m thickness of the fan are discussed, focusing on the fa n's 3-D architecture. sedimentary facies and processes. Foreset beds o n the upper slope of the Fan dip up to 22 degrees to the south and are dominated by ungraded to poorly graded debris-flow beds derived mainl y from subglacial (till) debris. Few deposits of meltwater outwash ori gin are found. The middle and lower parts of the fan slope are dominat ed by cohesionless debris-flow deposits intercalated with turbidites a nd debris-fall gravel. Scattered blocks of ice-rafted diamicton sugges t a calving tidewater ice front. Five allostratigraphic units are expo sed, inferred to have been formed by advance of the ice-front, stillst and, retreat, followed by readvance with proglacial thrusting, final r etreat and glacio-isostatic uplift. The initial ice-front advance and associated fan formation were most likely caused by a climatic deterio ration. Termination of the fan deposition was caused by retreat of the ice-front, attributed to the regional climatic amelioration at the en d of the Late Weichselian glaciation.