Francesca Micheletti

Dr. Francesca Micheletti

Department of Earth and Geo-environmental Sciences, University of Bari Aldo Moro, Via Edoardo Orabona, 4, 70126 Bari BA, Italy
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Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 October 2020 in Minerals
Verified
Journal Article
Open access
PDF file
AFAnnamaria Fornelli
Annamaria Fornelli
VFVincenzo Festa
Vincenzo Festa
FMFrancesca Micheletti
Francesca Micheletti
RSRichard Spiess
Richard Spiess
FTFabrizio Tursi
Fabrizio Tursi
The application of zircon dating to the reconstruction of orogenic systems is invaluable since time constraints of the geological evolution of orogens are crucial for the proposal of geodynamic and paleogeographic models. Zircon is one of the most promising accessory minerals in geochronology of crystalline basements because of its high-closure temperature. Moreover, U-Pb data of relict and recrystallized grains indicate the maximum sedimentation age as well as the timing of metamorphism in metasediments. In addition, the U-Pb ages of magmatic zircons constrain the timescale of magmatism. The Calabria–Peloritani terrane (CPT) represents a key area in the Southern Variscan Belt, whose reconstruction is still unresolved. Therefore, a review of literature zircon age data accompanied with new data from six samples of orthogneisses, paragneisses, amphibolites, and actinolite schists, helps to constrain the evolution of this Cadomian fragment, affected by metamorphic and magmatic Variscan events. A revisiting of the timing of the geological events from Paleo-proterozoic to Permian is revealed by comparing the internal textures of zircons and their U-Pb age clusters. The detected age peaks at 2500 Ma, 1600 Ma, and 1000 Ma in the CPT were related to a provenance from West and East Gondwana realms. A sedimentation age around 630 Ma emerges for the middle-deep crust terranes of the CPT, affected by Ediacaran (579–540 Ma) intrusions, accompanied by metamorphism dated at 556–509 Ma in the host metasediments. In the following, during Ordovician–Silurian extensional tectonics, the former Cadomian terranes were at least locally affected by fluid-assisted metamorphism (around 450 Ma) whereas the upper extensional basins that formed, were infilled by sediments along with interspersed volcanic to subvolcanic products. All these pre-Silurian terranes were involved in the subduction process of the Palaeotethys–Gondwana margin beneath Laurussia. The compressive phase began around 347 Ma, with under-thrusting of the formerly Gondwana substrate that was subjected to middle-high grade metamorphism, while the Ordovician–Silurian sediments were scraped off along the front of the Southern Variscan Belt and affected by low-grade metamorphism. Decompression of the whole Variscan orogenic system started around 320 Ma, together with uplifting of the chain and emplacement of widespread granitic intrusions which ended around 280 Ma and completed the Variscan orogenic cycle in the CPT.

14 October 2022 in Journal of Palaeogeography
Verified
Journal Article
Open access
AFAnnamaria Fornelli
Annamaria Fornelli
FMFrancesca Micheletti
Francesca Micheletti
SGSalvatore Gallicchio
Salvatore Gallicchio
FTFabrizio Tursi
Fabrizio Tursi
Sara CrinitiSara Criniti
Sara Criniti
SCSalvatore Critelli
Salvatore Critelli


22 February 2024 in Marine and Petroleum Geology
Verified
Journal Article
Closed access
HKHajar Kairouani
Hajar Kairouani
AAAnas Abbassi
Anas Abbassi
MZMohamed Najib Zaghloul
Mohamed Najib Zaghloul
MMMohamed El Mourabet
Mohamed El Mourabet
FMFrancesca Micheletti
Francesca Micheletti
Salvatore CritelliSalvatore Critelli
Salvatore Critelli

18 February 2021 in Journal of Metamorphic Geology
Verified
Journal Article
Closed access
PDF file
FTFabrizio Tursi
Fabrizio Tursi
PAPasquale Acquafredda
Pasquale Acquafredda
VFVincenzo Festa
Vincenzo Festa
AFAnnamaria Fornelli
Annamaria Fornelli
Antonio LangoneAntonio Langone
Antonio Langone
RSRichard Spiess
Richard Spiess

6 September 2020 in Minerals
Verified
Journal Article
Open access
PDF file
AFAnnamaria Fornelli
Annamaria Fornelli
SGSalvatore Gallicchio
Salvatore Gallicchio
FMFrancesca Micheletti
Francesca Micheletti
Antonio LangoneAntonio Langone
Antonio Langone
U-Pb spot ages have been determined on detrital zircons from two samples of volcaniclastic arenites belonging to the Tufiti di Tusa Formation (TTF) outcropping in the Lucanian Apennines (Southern Italy). Many petrographic and geochemical studies have been performed on these sandstones with the aim of defining their detritus source. A new and precise evaluation of the mineralogical composition of metamorphic lithic fragments, together with U-Pb detrital zircon ages, helps to clarify the deposition age of these syn-sedimentary volcaniclastic sandstones and constrains their source areas. Volcaniclastic arenites consist of andesitic fragments and single minerals of plagioclases, clinopyroxenes, and hornblendes, while the metamorphic lithics are mainly fragments of blue amphibole-bearing micaschists, serpentinites, ophicalcites, phyllites, and medium-grade micaschists. Phaneritic plutonic fragments consist of quartz, feldspar, and micas. Carbonate components include biomicritic and biosparitic fragments. Eighty age data collected from 56 zircons reveal a wide age spectrum, ranging from Neoarchean to Rupelian (from 2712 ± 25 to 30 ± 1 Millions of years (Ma)). The age data show that in volcaniclastic sandstones there is evidence of ancient crystalline basements involved in Cadomian and Variscan orogenesis (ages from 2712 ± 25 Ma to ≈260 Ma), whereas the measured ages of 157 Ma testify the events of Pangea fragmentation and the ages between 78 and 67 Ma are related to subduction metamorphism connected to the Alpine orogenesis. Fifty percent of the estimated detrital zircon ages show a mean concordant age of 33 ± 1 Ma, they have been measured on idiomorphic crystals with undisturbed magmatic oscillatory zoning. These data reveal the true sedimentation age of Tufiti di Tusa sandstones at least at the sampled levels, coeval with that recorded in other Rupelian volcaniclastic successions outcropping in the Northern Apennines and in the Western Alps (e.g., Val d’Aveto-Petrignacola Formation, Ranzano Formation and Taveyannaz Sandstone). These data represent preliminary suggestions of the sedimentation age of the Tufiti di Tusa Formation and Rupelian paleogeography in the Western Mediterranean area. During Priabonian-Rupelian times, the volcanic calc-alkaline detritus linked to a widespread syn-sedimentary igneous activity on the hinterland terranes of the foredeep basins in the Apennine-Maghrebian orogen extended from north to south in the Western-Central Mediterranean area.