Sources of iron-formations in the archean isua and malene supracrustals, West Greenland: Evidence from La-Ce and sm-nd isotopic data and REE abundances

Crustal evolution history of Korean Peninsula in East Asia: The significance of Nd, Ce isotopic and REE data from the Korean Precambrian gneisses.

“…Tanaka and Masuda (1982) applied the 138 La-138 Ce geochronometer to the Bushveld gabbro. Since then, the La-Ce system coupled with Sm-Nd system offers us an efficient tool to argue about LREE evolution (Tanaka et al, 1987;Shimizu et al, 1984Shimizu et al, , 1988Shimizu et al, , 1990aShimizu et al, , 1990bShimizu et al, , 1996. In order to compare the Sm-Nd and La-Ce isotope systematics for biotite and granitic gneisses, the data are shown in a ε Ce -ε Nd diagram (Fig.…”

Geochemistry of Nd and Ce isotopes and REE abundances in Precambrian orthogneiss clasts from the Kamiaso conglomerate, central Japan.

“…Sample 4-41 is con sidered as granite, although it was originally de scribed as granodioritic gneiss by Shibata and Adachi (1974). The experimental procedures used were those described previously by Shimizu et al (1988Shimizu et al ( , 1990. After decomposition of the rock powder (0.5-1 g) with HF and HC1O4, REE were sepa rated by an AG50W-X8 resin column in HC1 media.…”

Iron formations: A global record of Neoarchaean to Palaeoproterozoic environmental history

“…In some cases, 138 Ce systematics show that Ce anomalies in IFs are a feature produced by recent hydrothermal events and are not intrinsic to ancient seawater (Hayashi et al, 2004). Similarly, young 147 Nd isotope ages indicate post-depositional REE+Y mobility during metamorphic events (e.g., Shimizu et al, 1990). Such results highlight the need to consider the possibility of post-depositional REE+Y mobility in some IFs, particularly those that have been subjected to metamorphic and supergene alteration.…”

“…In the Archaean and Proterozoic oceans, ε Nd (t) values (which describe the deviation of the 143 Nd/ 144 Nd ratio measured in a sample relative to the 143 Nd/ 144 Nd ratio in a chondritic uniform reservoir at time t and in parts per 10 4 ) are estimated to have been +1 to +2 for deep waters dominated by hydrothermal sources, whereas values down to -3 would have been typical of shallow-waters dominated by terrestrial sources (Miller and O'Nions, 1985;PimentelKlose, 1988a, 1988b;Alexander et al, 2008). The relative contribution of continentally-sourced versus mantle-sourced REE+Y, discussed in more detail in the next section, has been estimated using Ce and Nd isotope compositions Wasserburg, 1980, Bau et al, 1997;Shimizu et al, 1990;Alexander et al, 2008;2009;Viehmann et al, 2015). In some cases, 138 Ce systematics show that Ce anomalies in IFs are a feature produced by recent hydrothermal events and are not intrinsic to ancient seawater (Hayashi et al, 2004).…”