FLUVIAL FEATURES IN THE DEEP-SEA - NEW INSIGHTS FROM THE GLACIGENIC SUBMARINE DRAINAGE SYSTEM OF THE NORTHWEST ATLANTIC MIDOCEAN CHANNEL INTHE LABRADOR SEA

Side-scan sonar imagery and seismic profiles from the submarine draina ge system of the Northwest Atlantic Mid-Ocean Channel (NAMOC) of the L abrador Sea reveal the presence of a variety of fluvial features in th e deep-sea. The analogies extend from mese-scale features to the basin -wide drainage pattern. At basin-scale, the NAMOC submarine drainage s ystem consists of downslope converging tributary canyons on the slope and yazoo-type tributary channels joining a central trunk-channel on t he basin floor In detail, the following fluvial features have been obs erved in NAMOC and its tributaries: meandering and braided channels an d talwegs, point bars (some with mese-scale bedforms), terraces, wash- over fans, submarine hanging valleys and chute pools, and levee gullyi ng and slumping. Some of these features are new and have not been reco gnised before in the deep-sea; others have not been documented in comp arable detail previously. Although the similarity of deep-sea turbidit e depositional features with fluvial features has long been recognised in the literature, fundamental differences exist between turbidite an d fluvial facies associations, the most noticeable of which is the lat eral juxtaposition of a meandering deep-sea channel and a submarine br aidplain. The latter has only been established for a glacigenic submar ine drainage system. The analogy with fluvial processes may be used in the quantification of flow processes of large-scale natural turbidity currents.