The continental slope and rise, east of Newfoundland, accommodates two distinct gravel populations. The upper slope (300-700 m depth) population is characterized by unstained, granules to boulders of predominantly granitic and terrigenous sedimentary compositon that show affinity to Paleozoic and Proterozoic rocks of Newfoundland and areas further north. The rise (2,500->3,000 m depth) population consists of iron- and ferromanganese-stained granules to cobbles composed mainly of carbonate that presumably has been derived from the high Canadian Arctic. The rise clasts are further distinguished in that they are finer grained, slightly more rounded and more altered by solution and/or boring organisms than their shallower water counterparts. The upper slope gravel has been reworked from underlying sediments, and deposited from ice rafts, and both processes are probably continuing today. Gravel on the rise has been concentrated through winnowing of middle Holocene sediments by the Western Boundary Undercurrent which appears to have been operative as a winnowing agent since about 4,000 to 5,000 y BP. The undercurrent has also affected the distribution of stained gravel which is most common and most intensely stained beneath a fast-flowing undercurrent core where environmental conditions resemble those documented for deep-sea, ferromanganese nodule fields.

From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.

Supplement to: Carter, Lionel (1979): Significance of Unstained and Stained Gravel on the Newfoundland Continental Slope and Rise. Journal of Sedimentary Research, 49(4), 1147-1158