| Summary: | On the basis of sedimentary structures and textures, six depositional facies have been identified in Labrador Slope, Rise and Basin cores. They include: (1) turbid-surface plume sediments (facies P; plumites) comprising 4% of the total length of the slope cores; (2) hemipelagic sediments (facies HI and H) with and without ice-rafted debris (IRD) (48% and 20% on the slope/rise and basin centre, respectively); (3) nepheloid-layer deposits (facies N; 9% on the slope); (4) contourites (facies C; 4% on the slope); (5) turbidite facies (30% on the slope and $>$40% on the levees of the Northwest Atlantic Mid-Ocean Channel, NAMOC) with three subfacies: thin-bedded silt and mud turbidites (T); turbidites with laminae of IRD (TI), and sand turbidites (MS); and (6) debris-flow facies (10% on the slope) with four subfacies: gravelly (D1), sandy silt (D2), thin bedded (D3) and sandy gravelly debris-flow deposits (D4). Facies P occurs on high-relief slope sections, deposited by buoyantly rising meltwater plumes entrained by the south-flowing Labrador Current. The high relief was caused by retrograde canyon erosion after deposition. Facies N is best developed and thickest on the slope and upper rise. It was deposited when sediment-laden meltwater from the Laurentide Ice Sheet with high concentrations of suspended sediment spread out in mid-water or along the bottom. Facies T occurs on the levees of the NAMOC and its tributaries. It originated from the remobilization of detrital carbonate-rich sediments on the slope south of the Hudson Strait. Extensive sand turbidites occur on a braided floodplain east of NAMOC. Deposition of sand turbidites by high-density turbidity currents, probably of sheet-flow type, resulted from bedload-rich meltwater discharges on the low-relief slope sector off the Hudson Strait. They may have been caused by subglacial-lake outburst flooding, which might be linked to Heinrich events. Facies C occurs on the lower slope to upper rise. Facies H is present in all parts of the basin but most abundant on the slope; together with facies T, it is the major facies in the intercanyon regions. Facies D is found mainly on low-relief slope sectors, in front and north of major glacier outlets. Debris-flow tongues in the slope canyons merge downslope forming an extensive stacked megadebris-flow deposit on the floodplain west of NAMOC. Facies D makes up $>$75% of the sediment thickness in the western floodplain cores. Four types of Heinrich layers (HL) were identified. (Abstract shortened by UMI.)
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