Premetamorphic lateritisation in Proterozoic metabasites of Rogaland, SW Norway

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Authors:Bol, L. C. G. M.; Maijer, C.; Jansen, J. B. H.
Author Affiliations:Primary:
Univ. Utrecht, Inst. Earth Sci., Dep. Chem. Geol., NL-3584 CD Utrecht, Netherlands
Volume Title:Contributions to Mineralogy and Petrology
Source:Contributions to Mineralogy and Petrology, 103(3), p.306-316. Publisher: Springer International, Heidelberg-New York, International. ISSN: 0010-7999
Publication Date:1989
Note:In English. 62 refs.; illus. incl. chart, 3 tables, geol. sketch map
Summary:Heterogeneous layers of granulite-facies metamorphic basic rocks of the Proterozoic supracrustal Faurefjell formation in Rogoland display an extreme chemical variation. Within a single layer, the bulk chemical composition gradually changes from approximately basic to basic granulites to alumina-Fe-rich in granofelses. Component ratios and composition-volume relations indicate open- system chemical reactions mainly involving the extraction of silica. Apparent enrichment in Fe, Ti, P, Al, Zr, Ni, Co, Zn, Y, Nb, Hf and REE and variations in resulting metamorphic mineral assemblages are related to premetamorphic progressive lateritization of a basaltic protolith. The weathering generated a continuous chemical suite from SiO2 48, Fe2O3 10 and Al2O3 19 wt.% in the basic granulites to 14, 40 and 25 wt.% in the Fe-Al granofelses. Metasomatism during diagenesis and during (very) high-grade metamorphism (1200-900 m.y.) further perturbed the concentrations of relatively mobile elements Ca, Mg, K, Rb, Sr, Ba, Na and Li in the laterites without affecting the transition metal ratios. In particular, the REE did not fractionate differentially during the supracrustal and metasomatic alteration. [P.Br.]
Subjects:Chemical composition; Laterization; Metabasite; Metaigneous rocks; Metamorphic rocks; Metasomatism; Petrology; Precambrian; Proterozoic; Upper Precambrian; Europe; Norway; Rogaland Norway; Scandinavia; Southern Norway; Western Europe
Abstract Numbers:90M/1758
Record ID:1993039351
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from Geoline, Bundesanstalt fur Geowissenschaften und Rohstoffe
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