A B S T R A C T : Present-day marine sediments around the emerged basaltic areas of Iceland and the Faeroe Islands are characterized by the abundance and predominance of smectites. Smectites increase regularly and systematically near volcanic areas. Their origin from (i) meteoric/ deuteric weathering, (ii) hydrothermal products, (iii) neoformation in the marine environment or (iv) transformation during their transport to or stay in oceanic regions is considered in a comparative study of three types of environments on or near the Faeroe Islands. These are (1) a basaltic environment where phyllite minerals of deuteric and hydrothermal origin are abundant; (2) a soil environment formed on basaltic flows; (3) a marine sedimentary environment within adjacent sedimentary basins. This investigation clearly shows the link between hydrothermal and deuteric saponite--celadonite in basalt, Fe,Mg-smectite in Faeroe soils and Fe-smectite in marine sediments.A question often considered by geologists (e.g. Yeroshchev-Shak, 1964;Griffin et al., 1968;Rateev et al., 1969) is the abundance, and often predominance, of smectite in clay assemblages within the Icelandic Basin of the N Atlantic. There is general agreement that smectites increase near the emerged basaltic areas of Iceland and the Faeroe Islands. This increase appears to be constant and characterizes Quaternary sedimentation in the NE Atlantic both during the glacial and interglacial periods (Parra, 1980;Zimmerman, 1982). Much controversy exists, however, about the location of supply provinces. YeroshchevShak (1964), for instance, suggests on the basis of the disposition of smectite haloes surrounding Iceland that smectites derive from oceanic basaltic rocks, whereas Biscaye (1965), Griffin et al. (1968) and Rateev et al. (1969) imply that they originate from continental areas.Results of more recent investigations imply a positive correlation between the basaltic character of detrital inputs (supplied by the Iceland-Faeroe region) and the abundance of smectites (Zimmerman, 1975;Parra, 1982). Near Iceland, smectites represent almost 100% of the clay mineral assemblage (Grousset et al., 1982;Grousset, 1983).Pedologic studies have shown that some smectites form by meteoric weathering of a variety of rock types under certain very specific climatic conditions, namely those of tropical reducing environments (Pedro, 1966). This, of course, is not the case for the Quaternary Iceland-Faeroe province which has a cold and humid climate in which pedogenesis is relatively inactive; the soils are thin and poorly developed and characterized 9 1985 The Mineralogical Society
