Rare Earth Elements REE as Redox Indicators

More recently, Kastenet al. (1998) have determined the REE contents of a suite of manganese nodules from the South Atlantic to see if a similar relationship between the Ce/La ratios of the nodules and AABW flow could be observed there. In fact, the Ce/La ratios of the nodules decrease in the sequence Lazarev Sea, Weddell Sea (10.4 and 9.7) East Georgia Basin (6.5- 

Of particular interest in this regard is the study of REE patterns of different types of nodules from DOMES Site A in the C-C F.Z. by Calvert et al. (1987) on nodules which had previously been investigated by Piper and Blueford (1982) and Calvert and Piper 

Site A may be better interpreted in terms of variations in nodule type within the area rather than local variations in seawater chemistry as proposed by Calvert et al. (1987). 

In addition, De Carlo and McMurtiy (1992) have analyzed 32 samples of Co-rich Mn crasts from the Hawaiian Archipelago for REE (see section 11.4.4). These samples contained on average 287 ppm La and 

277 ppm Ce giving an average Ce/La ratio of 4.5. This is intermediate between the ratios in nodules from the Aitutaki Passage (Area K) and the C.C. FZ (Area C) and is compatible with a hydrogenous origin for these cmsts. 

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