The Adriatic microplate is a key player in the Western Mediterranean tectonic puzzle, but its Oligocene-Miocene dynamics are not yet fully understood. In fact, even though the timing and magnitude of Adriatic slab rollback and backarc extension in the Apennines have long been established, the timing of progressive Adria indentation beneath the Central Alps and major strike-slip motion along the Insubric fault are still poorly constrained. Here we tackle these issues by utilizing detrital zircon U-Pb geochronology on Adriatic foredeep turbidites, i.e., by comparing the geochronologic fingerprints of the exhuming tectonic domes of the Central Alps (Ticino and Toce subdomes) with those of the Oligocene-Miocene turbidites chiefly derived from their erosion. We analyzed 11 sandstone samples ranging in age from 32 to 18 Ma. The ratio between Variscan and Caledonian zircon grains (which are dominant in the Toce and Ticino subdomes, respectively) sharply increases at ca. 24-23 Ma. This major provenance change marks the westward shift of the Adriatic indenter beneath the Central Alps and the associated right-lateral activity of the Insubric fault. The coexistence of strike-slip motion at the northern boundary of the Adriatic microplate at ca. 24-23 Ma and trench retreat during scissor-type backarc opening to the west requires a near-vertical rotation axis located at the northern tip of the Ligurian-Provençal basin. We propose that the rotation axis position was controlled by the interaction between the European and the Adriatic slabs, which may have collided at depth by the end of the Oligocene, triggering the westward shift of the Adriatic indenter beneath the Central Alps.

Malusa', M., Anfinson, O., Dafov, L., Stockli, D. (2016). Tracking Adria indentation beneath the Alps by detrital zircon U-Pb geochronology: Implications for the Oligocene-Miocene dynamics of the Adriatic microplate. GEOLOGY, 44(2), 155-158 [10.1130/G37407.1].

Tracking Adria indentation beneath the Alps by detrital zircon U-Pb geochronology: Implications for the Oligocene-Miocene dynamics of the Adriatic microplate

MALUSA', MARCO GIOVANNI;
2016

Abstract

The Adriatic microplate is a key player in the Western Mediterranean tectonic puzzle, but its Oligocene-Miocene dynamics are not yet fully understood. In fact, even though the timing and magnitude of Adriatic slab rollback and backarc extension in the Apennines have long been established, the timing of progressive Adria indentation beneath the Central Alps and major strike-slip motion along the Insubric fault are still poorly constrained. Here we tackle these issues by utilizing detrital zircon U-Pb geochronology on Adriatic foredeep turbidites, i.e., by comparing the geochronologic fingerprints of the exhuming tectonic domes of the Central Alps (Ticino and Toce subdomes) with those of the Oligocene-Miocene turbidites chiefly derived from their erosion. We analyzed 11 sandstone samples ranging in age from 32 to 18 Ma. The ratio between Variscan and Caledonian zircon grains (which are dominant in the Toce and Ticino subdomes, respectively) sharply increases at ca. 24-23 Ma. This major provenance change marks the westward shift of the Adriatic indenter beneath the Central Alps and the associated right-lateral activity of the Insubric fault. The coexistence of strike-slip motion at the northern boundary of the Adriatic microplate at ca. 24-23 Ma and trench retreat during scissor-type backarc opening to the west requires a near-vertical rotation axis located at the northern tip of the Ligurian-Provençal basin. We propose that the rotation axis position was controlled by the interaction between the European and the Adriatic slabs, which may have collided at depth by the end of the Oligocene, triggering the westward shift of the Adriatic indenter beneath the Central Alps.
Articolo in rivista - Articolo scientifico
Alps, Apennines, Lepontine dome, Insubric fault, detrital geochronology, slab interaction, Ligurian-Provençal basin
English
2016
44
2
155
158
partially_open
Malusa', M., Anfinson, O., Dafov, L., Stockli, D. (2016). Tracking Adria indentation beneath the Alps by detrital zircon U-Pb geochronology: Implications for the Oligocene-Miocene dynamics of the Adriatic microplate. GEOLOGY, 44(2), 155-158 [10.1130/G37407.1].
File in questo prodotto:
File Dimensione Formato  
Malusa et al 2016 Geology - post-print.pdf

Accesso Aperto

Tipologia di allegato: Author’s Accepted Manuscript, AAM (Post-print)
Dimensione 657.87 kB
Formato Adobe PDF
657.87 kB Adobe PDF Visualizza/Apri
Malusa et al 2016 - Geology.pdf

Solo gestori archivio

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 428.79 kB
Formato Adobe PDF
428.79 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/107594
Citazioni
  • Scopus 39
  • ???jsp.display-item.citation.isi??? 38
Social impact