Geochemistry of Late Cretaceous-Oligocenic shales from the Varicolori Formation, Southern Apennines, Italy; implications for mineralogical, grain-size control and provenance

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doi: 10.1127/ejm/8/4/0733
Authors:Mongelli, Giovanni; Cullers, Robert L.; Muelheisen, Stephen
Author Affiliations:Primary:
Universita della Basilicata, DiSGG, Potenza, Italy
Other:
Kansas State University, United States
University of Tennessee, United States
Volume Title:European Journal of Mineralogy
Source:European Journal of Mineralogy, 8(4), p.733-754. Publisher: Schweizerbart'sche Verlagsbuchhandlung (Nägele u. Obermiller), Stuttgart, Federal Republic of Germany. ISSN: 0935-1221
Publication Date:1996
Note:In English. 62 refs.; illus., incl. 7 tables, geol. sketch map
Summary:Shales from this formation, and size fractions from them, were analysed for major and trace elements, including the REE. The shales consist mainly of illite and smectite, with lesser chlorite, kaolinite, quartz and feldspar, together with variable calcite (0-28 wt.%) and accessory garnet, zircon, apatite, xenotime and an unidentified Ti oxide. Factor analysis suggests that most trace elements are controlled by accessory minerals rather than by major minerals; thus mass-balance calculations show that 50% of La, 83% of Sm, and 100% of Tb and Yb can be due to monazite, xenotime and apatite. The total contribution of phosphatic phases and zircon to Eu contents, however, is minor (16%), whereas the contribution of the feldspars is limited to ∼ 30%; a significant amount of Eu can thus be controlled by 2:1 clay phases. The lowest concentration densities for most trace elements are in the finer fractions dominated by clay minerals; in contrast, the highest concentration densities for most trace elements are in the silt-sized fractions dominated by chlorite, quartz or calcite. The Eu/Eu* and Th/Sc ratios are the most similar in different size fractions, whereas the Cr/Th and Co/Th ratios are very variable. In these shales the mineralogy and elemental ratios suggest a provenance of low- to medium-grade metamorphic rocks of intermediate crustal composition, remnants of which currently form the Calabrian-Peloritan arc. [R.A.H.]
Subjects:Accessory minerals; Cenozoic; Clay minerals; Cretaceous; Geochemistry; Mass balance; Mesozoic; Oligocene; Paleogene; Provenance; Sheet silicates; Silicates; Statistical analysis; Tertiary; Upper Cretaceous; X-ray data; Apennines; Europe; Italy; Southern Apennines; Southern Europe; Varicolori Formation
Coordinates:N403000 N411500 E0170000 E0150000
Abstract Numbers:97M/686
Record ID:1996066130
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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