Many of the sand-sized silicate grains recovered during the abortive drilling at Site 276 are polished, iron stained, or coated with black or brown ferruginous material. Examination of eight representative grains with the scanning electron microscope and energy-dispersive X-ray analyzer shows that the ferruginous coatings are of two types: (1) black scale generally preferentially developed in grain surface depressions, and (2) smooth brown sheaths of hydroust(?) iron that completeley envelope grains. The black scale typically contains major amounts of Fe, minor Si, and traces of Al, K, Ca, Ti, and Mn. The polish exhibited by many quartz and feldspar grains results from development of a smooth coating of silica containing minor or trace Fe. The coatings on the detrital silicate grains at Site 276 indicate that the western boundary current, which impinges on the site, is oxygenated, and silica rich. The results of the study show that iron staining, and the formation of siliceous and ferruginous coatings, can occur at oceanic depths (4671 m).

West: 146.0000 East: 176.4824 North: -46.0000 South: -60.0000

West: NaN East: NaN North: NaN South: NaN

Expedition: 29

Site: 29-276

Provider: SEDIS Publication Catalogue

Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/dsdp.proc.29.132.1975 (c.f. for more detailed metadata)

Data download: application/pdf

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