Latest Precambrian to Early Cambrian U–Pb zircon ages of augen gneisses from Calabria (Italy), with inference to the Alboran microplate in the evolution of the peri-Gondwana terranes |
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| Authors: | Francesca Micheletti Pierre Barbey Annamaria Fornelli Giuseppe Piccarreta Etienne Deloule |
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| Institution: | (1) Dipartimento Geomineralogico, Bari University, via Orabona 4, 70125 Bari, Italy;(2) CRPG-CNRS, B. P. 20, 54501 Vandoeuvre-lès-Nancy Cedex, France |
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| Abstract: | In situ U–Pb dating of zircons from five samples of Calabrian augen gneisses shows that their protoliths are Latest Precambrian
to Early Cambrian in age (562 ± 15, 547 ± 7, 540 ± 4, 539 ± 16 and 526 ± 10 Ma), and contain Archaean (3.1 Ga), Palaeoproterozoic
(1.7–2.4 Ga) and Neoproterozoic (0.6–0.9 Ga) inheritance. Geochemical signature of augen gneisses is typical of high-K calc-alkaline
post-collisional magmatism. Their Sr–Nd isotopic compositions 0.7093 < (87Sr/86Sr)i < 0.7139; −3.2 < ɛNd(t) < −5.4; 1.5 < T
DM < 1.7 Ga] indicate the involvement of a crustal component in significant proportions. The Calabrian augen gneisses have,
therefore, to be distinguished from the orthogneisses of Sardinia and northern Algeria, and from the porphyroids of Sicily,
which are Middle Ordovician. By contrast, the Calabrian augen gneisses show a close similarity to the Pan-African post-collisional
granitoids of the northern edge of the West African craton (e.g. the Moroccan Anti-Atlas). This suggests a peri-Gondwana origin
and corroborates previous palaeogeodynamic reconstructions attributing the Alboran microplate to the northern margin of the
West African craton. |
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| Keywords: | Latest Precambrian to Early Cambrian Calabria Alboran microplate U– Pb dating Zircon |
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