A case study of in situ analyses (major and trace elements, U-Pb geochronology and Hf-O isotopes) of a zircon megacryst: implication for the evolution of the Egéré terrane (Central Hoggar, Tuareg Shield, Algeria)

Bruguier, Olivier; Caby, Renaud; Bosch, Delphine; Ouzegane, Khadidja; Deloule, Étienne; Dhuime, Bruno; Bendaoud, Abderhamane; Kiénast, Jean-Robert

doi:10.7185/gold2021.6913

Cited by 1 publication

(1 citation statement)

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“…The correction for the interferences and mass bias followed the procedure outlined in previous reports [e.g. Bruguier et al, 2020]. The correction for the isobaric interference of Yb and Lu on 176 Hf was made following a method detailed in Fisher et al [2011].…”

Section: Zircon Hf Analysesmentioning

confidence: 99%

Insights on the Permian tuff beds from the Saint-Affrique Basin (Massif Central, France): an integrated geochemical and geochronological study

Poujol¹,

Mercuzot²,

López³

et al. 2024

Comptes Rendus. Géoscience

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The Permian marks the transition between the end of the accretion of the supercontinent Pangea and the beginning of its dislocation. In the Eastern Pangea intertropical domain (i.e. the present-day Western Europe), the late-Paleozoic (i.e. uppermost Carboniferous-Permian) history remains poorly constrained due to the lack of precise radiometric data. This is particularly true for Permian basins from the southern part of the French Massif Central, making it difficult to determine correlations between basins and therefore robust timings and constraints on the environmental and climate events described in these basins, and to compare them with the larger-scale settings. This article focuses on the Saint-Affrique Basin, via an integrated petrological, geochemical and geochronological study of eight of the volcanic-ash levels interbedded in the sedimentary succession. It highlights the existence of two different groups of felsic volcaniclastic rocks. The first group, located at the base of the basin and attributed to the Stephanian continental stage, is related to a late-orogenic volcanic setting and corresponds to calc-alkaline trachy-andesitic tuffites that could not be dated due to the lack of volcanic zircon. The second group, located towards the top of the succession, is composed of calc-alkaline dacitic ash beds and tuffites yielding Kungurian ages, i.e. late early Permian (Cisuralian, 283.5 ± 0.6 to 273.01 ± 0.14 Ma), and are attributed to a post-orogenic deposition setting. These ages show that the sedimentary filling of the basin is younger than hitherto expected (i.e. Artinskian, 290.1 ± 0.26 to 283.5 ± 0.6 Ma). The elemental geochemistry, the presence of inherited detrital zircons and the Hf signatures of the volcanic ones indicate the involvement of an old (Proterozoic * Corresponding author.

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Section: Zircon Hf Analysesmentioning

confidence: 99%