Long-Term Tectono-Stratigraphic Evolution of a Propagating Rift System, L’Aquila Intermontane Basin (Central Apennines)
Journal
Tectonics
Date Issued
2024
Author(s)
Arriga, Giorgio
Marchegiano, Marta
Peral, Marion
Hu, Hsun-Ming
Cosentino, Domenico
Dalton, Hayden
Brilli, Mauro
Aldega, Luca
Claeys, Philippe
Rossetti, Federico
Abstract
Understanding the long-term tectono-stratigraphic evolution of active extensional faulting is crucial for unraveling the mode through which continental rifting propagates in space and time. The Pliocene-Quaternary L’Aquila Intermontane Basin (AIB) in central Apennines offers a natural laboratory for studying a propagating continental rift. Seismicity is related to NW-SE-striking normal faults that have been accommodating crustal stretching since the Late Pliocene. Through a multidisciplinary approach integrating field, mineralogical, geochemical (C-O stable and clumped isotopes) and geochronological (40Ar/39Ar, U-Th) analyses, this study focuses on the structural connection between the Mount Pettino Fault (MPF) and the Paganica Fault, two active, left-stepped basin boundary faults of the AIB. A two-stage tectono-stratigraphic evolution is proposed during transition from localized to delocalized deformation and fault linkage. Stage-1 (pre-Middle Pleistocene) corresponds to nucleation and growth of the MPF, characterized by a ∼5 m thick exhumed fault core, consisting of an isotopically closed cataclasite (T (∆47) ∼33–50°C). Stage-2 corresponds to the development of a distributed zone of NW-SE and E-W extensional faulting in the overlay zone with the Paganica Fault, which is interpreted as a transfer zone linking the basin boundary faults, with maximum long-term slip rates comparable to those of the connected faults. Structurally controlled circulation of meteoric fluids promoted carbonate veining and travertine formation (T (∆47) ∼8°C). U-Th carbonate dating of Stage-2 mineralizations constrains the tectonic activity in the transfer zone at least at ∼182–331 ka. Implications on the tectono-stratigraphic evolution and on the seismotectonic scenario of the AIB are discussed, providing geodynamic inference at regional scale.
Subjects
Ar-Ar geochronology
C-O isotopes systematics
fault linkage
structural geology
tectonics and sedimentation
U-Th carbonate geochronology
SDGs
Type
journal article