|Tin placer deposits on continental shelves|
Yim, W.W.-S. (2000). Tin placer deposits on continental shelves, in: Cronan, D.S. (Ed.) Handbook of marine mineral deposits. pp. 27-66
In: Cronan, D.S. (Ed.) (2000). Handbook of marine mineral deposits. CRC Marine Science Series, 17. CRC Press: Boca Raton. ISBN 0-8493-8429-X. 406 pp., more
In: Kennish, M.J.; Lutz, P.L. (Ed.) CRC Marine Science Series., more
A review of the geology of tin placer deposits on continental shelves is attempted. Under the heading of general characteristics, primary tin mineralization, distance of transport of cassiterite, dating and age of formation, concentration, preservation, and classification are examined. In the formation of giant deposits on continental shelves, the drowning of old river systems are recognized to be the most important by far. The tin placer deposits are divisible into eluvial deposits, conuvial deposits, alluvial deposits, beach deposits, and reworked mine tailings. Methods used for their exploration, including geophysics, drilling, chemical, and mineralogical, are presented. This is folIowed by a description of case studies of tin placer deposits on continental shelves including southeast Asia, southern China, Cornwall, and Australia. Finally, conclusions are drawn on the evolution of tin placer deposits through time, research and development, and future prospects. The lack of offshore tin exploitation outside southeast Asia is attributed to inadequate understanding of the distance of transport required to form economic tin placers, the localized nature of bedrock mineralization and its resultant placers, and limitations on the methods of prospecting used. Because "long" geological time periods are now known to be involved in the development of giant onshore tin placers, the same may wen apply to their offshore counterparts.