A fluvial-dominated lacustrine delta in a volcanic province, W Greenland

A 50 m thick sequence of dark grey to black non-marine shales are exposed in a 12 km section along the NE coast of Disko in W Greenland. The shales are sandwiched between sandy fluvial deposits, and the sedimentological logs demonstrate a marked lateral continuity of facies within the shale unit. The shale is fissile and micaceous, and contains locally comminuted plant debris. The average total organic carbon (TOC) content is 6%, the organic matter corresponds to type III kerogen and the dominant clay mineral is kaolinite. The shale unit constitutes one coarsening-upward sequence interpreted as lacustrine prodelta mud, with thin sheets of sand deposited from density underflows which pass transitionally up into cross-laminated mouth-bar sand finally overlain by cross-bedded sand deposited in fluvial channels. This sequence represents progradation of a fluvial-dominated delta into a lake partially bounded by subaqueous hyaloclastic breccias.