Controls on the fractionation of isovalent trace elements in magmatic and aqueous systems: Evidence from Y/Ho, Zr/Hf, and lanthanide tetrad effect - a discussion of the article by M. Bau (1996)
Article Abstract:
A study involved rare-earth element (REE) geochemistry in fluorapatite from rare-metal pegmatites linked with S-type peraluminous granites. This led to agreement by the author with Bau (1996) that the anomalous Nd and Ho/Er in highly evolved leucogranites and pegmatites are not analytical artifacts. However the author points to the discontinuity at HO/Er in REE patterns in leucogranites and pegmatites, which is attributed to fractional crystallization involving monazite. This does not support the lanthanide 'tetrad' effect or fractionation of REE by chemical complexation in magmatic systems advocated by Bau (1996).
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1997
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The lanthanide tetrad effect in highly evolved felsic igneous rocks - a reply to the comment by Y. Pan
Article Abstract:
The behaviour of Y-Ho, Zr-Hf in aqueous media cannot be adequately explained, although it has been shown that anomalous behaviour of the REE is linked with anomalous fractionation of the geo-chemical twin pairs Y-Ho and Zr-Hf. The lanthanide tetrad effect is controversial and Y. Pan (1997) suggests that the Ho/Er discontinuity in REE patterns of leucogranites and pegmatites, could be the result of conventional magmatic crystallization. However the author believes that fractional crystallization does not adequately explain distributions of Y, REE, Zr and Hf.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1997
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Controls on the fractionation of isovalent trace elements in magmatic and aqueous systems: evidence from Y/Ho, Zr/Hf, and lanthanide tetrad effect
Article Abstract:
The trace elements Y, Ho, Zr, and Hf show Charge-and Radius-Controled (CHARAC) behavior in pure silicate melts and a non-CHARAC behavior in aqueous systems which is dependent on the physicochemical nature of the magma. The fractionation of the trace elements in the aqueous systems is controlled by chemical complexation which depends on the element's ionic charge, radius, and electronic configuration, and the coordinating ligand. CHARAC behavior is characterized by Y/Ho and Zr/Hf ratios that are similar to the chondritic ratios.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
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