Lanthanide tetrad effect observed in marine environment.

Masuda, Akimasa; Ikeuchi, Yoshihiro

doi:10.2343/geochemj.13.19

Cited by 195 publications

(106 citation statements)

References 9 publications

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“…The (Pr/ Yb) cn ratio gives a measure of the overall slope of the normalized plot if this can be approximated as a straight line, and thereby the extent of fractionation of the LREEs from the HREEs. The (La/Yb) cn ratio is more frequently used as an index of REE fractionation, but lanthanum is often depleted relative to other trivalent REEs because of tetrad effect (Peppard et al, 1969;Masuda and Ikeuchi, 1979). Therefore the (Pr/Yb) cn ratio is mostly discussed in the present paper.…”

Section: Analytical Methods and Ree Terminologymentioning

confidence: 99%

“…It is noticeable that the garnet shows REE patterns different from those of limestone and has no negative Ce anomaly. A depletion of La is probably due to tetrad effect (Peppard et al, 1969;Masuda and Ikeuchi, 1979). The limestone-normalized REE pattern of garnet is characterized by large positive Ce and Eu anomalies and high normalized values more than one (Fig.…”

Section: Yoshiwara-sannotake Cu(-fe) Depositsmentioning

confidence: 99%

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Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Kato

1999

Resource Geology

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: Systematic data of rare earth elements (REEs) are presented in order to put some constraints on the origin of hydrothermal fluids responsible for two contrastive skarn deposits in Japan; the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(‐Fe) deposits. Carbon and oxygen isotopic studies have demonstrated that the hydrothermal fluids responsible for the Kamioka Zn‐Pb deposits are of meteoric water origin whereas those for the Yoshiwara‐Sannotake Cu(‐Fe) deposits are of magmatic water origin. The REE abundances of epidote skarn derived from aluminous rocks, garnet and clinopyroxene in calcic exoskarn derived from limestone, and interstitial calcite associated with sulfide minerals were determined for these contrastive skarn deposits by inductively‐coupled plasma mass spectrometry (ICP‐MS). A significant difference in the REE concentrations is not found between epidote skarn and aluminous original rock (plagioclase‐clinopyroxene rock, called Inishi rock) from the Kamioka Zn‐Pb deposits, indicating that the REEs are generally immobile during the formation of epidote skarn, and that the REE concentrations of the hydrothermal fluid are considerably low relative to the aluminous original rock. In contrast, the epidote skarn exhibits enrichment of Eu with increasing total REE concentrations relative to the aluminous original rock (quartz diorite) in the Yoshiwara‐Sannotake Cu(‐Fe) deposits, implying a contribution of magmatic fluid derived from granitoids during the skarn formation. Limestone generally has much lower REE concentrations related to surrounding aluminous rocks, and thus the REE concentrations of garnet and clinopyroxene in calcic exoskarn, originated from limestone, are variable due to the interaction with the hydrothermal fluids. The chondrite‐normalized REE patterns of garnet, clinopyroxene, and interstitial calcite exactly provide useful information on origins of hydrothermal fluids. The REE patterns of these minerals from the Kamioka Zn‐Pb deposits show lower (Pr/Yb)cn ratios, and negative Ce and Eu anomalies inherited from limestone with the decrease of This suggests that the hydrothermal fluids responsible for the Kamioka Zn‐Pb deposits were depleted in REEs, and were not magmatic water in origin, but presumably meteoric one. In striking contrast, the REE patterns of exoskarn minerals and calcite from the Yoshiwara‐Sannotake Cu(‐Fe) deposits exhibit a positive Eu anomaly, and high (Pr/Yb)cn ratios with the considerable increase of σREE and the disappearance of negative Ce anomaly, implying that the fluids were dominantly of magmatic origin. The REE indices are very likely to be an excellent indicator to origins of the skarn deposits.

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Section: Analytical Methods and Ree Terminologymentioning

confidence: 99%

Section: Yoshiwara-sannotake Cu(-fe) Depositsmentioning

confidence: 99%

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Kato

1999

Resource Geology

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“…The data obtained are given in Table 3 the corresponding chondrite-normalized Zigzag features in heavy REE and discontinuity between Eu and Gd As mentioned before, Masuda and Ikeuchi (1979) The REE features observed in seawater might be explained by some chemical properties of REE in solution. De Baar et al (1985b) touched upon the possible effect of the hydration numbers of REE ions in aqueous solution.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, Masuda and Ikeuchi (1979) recognized a zigzag feature in heavy REE pattern .of seawater, and interpreted it as a reflec tion of partially cut-off lanthanide tetrad effect. The tetrad effect is considered to be associated with the 4f electron filling (Nugent, 1970).…”

Section: Introductionmentioning

confidence: 99%

Features of the heavy rare-earth elements in seawater.

1990

Self Cite

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The rare earth element (REE) abundances in twenty-one seawater samples around the Japanese Islands have been precisely determined by the isotope dilution method. Besides Ce anomaly, REE pat terns of the seawater samples show a zigzag feature reflecting the lanthanide tetrad effect, which is con sidered to be associated with the filling of 4f electron orbitals. Particularly, the third and the fourth tetrads, zigzags in Gd-Dy-Er and Er-Yb-Lu spans, are clearly observed. Furthermore, most of the REE patterns shown here demonstrate a straight line for La-Nd-Sm-Eu and a discontinuity between Eu and Gd. The degree of the third tetrad effect becomes larger with the increase of the discontinuity be tween Eu and Gd.

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“…Moreover Dy plots on a point lower than the smooth line connecting Gd, Er, and Lu. This type of REE pattern has been well known for sea water and is thought to reflect the lanthanide tetrad effect (Masuda and Ikeuchi, 1979), suggesting that hydrous altera tion (or serpentinization) considerably modified the REE chemistry of the ultramafic rock. Thus, our result is rather different from that suggested by Prinzhofer and Allegre (1985) and Suen and Frey (1987); that is, serpentinization of ultramafic rocks does not appear to alter significantly the REE composition.…”

Section: Rare Earth Elementsmentioning

confidence: 99%

REE characteristics of mafic rocks from a fore-arc seamount in the Izu-Ogasawara region, western Pacific.

et al. 1992

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We have analyzed major, minor, and rare earth elements (REE) in basalts, dolerites, gabbros and an amphibolite from a fore-arc seamount "Ogasawara Paleoland (OPL)" in the Izu-Ogasawara region, western Pacific. Barium and REE compositions of the OPL mafic rocks suggest that they were formed in a mid-ocean ridge. This interpretation is supported by the similarity of the Ti02-A1203 systematics of the OPL mafic rocks to those of mid-ocean ridge basalts. To explain the occurrence of MORB-type mafic rocks in a fore-arc region, two possibilities are considered; (1) accreted oceanic crust of subduc ting slab, or (2) trapped oceanic crust remained in the fore-arc region when the subduction had initiated.

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Lanthanide tetrad effect observed in marine environment.

Cited by 195 publications

References 9 publications

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn‐Pb and Yoshiwara‐Sannotake Cu(–Fe) Deposits in Japan

Features of the heavy rare-earth elements in seawater.

REE characteristics of mafic rocks from a fore-arc seamount in the Izu-Ogasawara region, western Pacific.

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