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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 994

Last Page: 994

Title: Mineral Deposits at Shelf-Slope Break: ABSTRACT

Author(s): Peter A. Smith

Article Type: Meeting abstract


Sedimentologic, geochemical, and tectonic processes, both past and present, in the vicinity of the shelf-slope boundary have created favorable conditions for the formation and accumulation of a range of mineral deposits. Phosphorites and authigenic sulphides are probably the most important but other deposits, including heavy mineral placers and aggregates, are of interest. The nature and formation of these deposits are reviewed with particular reference to the relevant processes which characterize the outer shelf and upper continental slope. These processes include the reworking of consolidated deposits which crop out on the outer shelf; authigenic sulphide formation in intra-slope basins or where the oxygen-minimum layer intersects the outer shelf or upper slope; the acc mulation of heavy mineral placers along ancient strandlines and the subsequent reworking during the passage of the transgressing shoreline; authigenic mineral formation in relict sediments; and the bypassing of the outer shelf by recent, terrigenous sediment which might otherwise dilute the valuable minerals present.

An attempt is made to realistically appraise the economic potential of the mineral deposits found close to the shelf-slope boundary. Although at present they are nothing more than a gleam in the marine prospector's eye, strategic considerations, the availability of local markets for the commodities produced, and the depletion in the available land-based resources could make such deposits economically viable in the not-too-distant future.

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