Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy)
Detailed geological field mapping, integrated with meso- and microstructural investigations, kinematic of the flow and finite strain analyses, combined with geochronology, are fundamental tools to obtain information on the temperature–deformation–timing path of crystalline rocks and shear zone. The...
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MDPI AG
2020-07-01
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| Series: | Geosciences |
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| Online Access: | https://www.mdpi.com/2076-3263/10/8/288 |
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| author | Rodolfo Carosi Alessandro Petroccia Salvatore Iaccarino Matteo Simonetti Antonio Langone Chiara Montomoli |
| author_facet | Rodolfo Carosi Alessandro Petroccia Salvatore Iaccarino Matteo Simonetti Antonio Langone Chiara Montomoli |
| author_sort | Rodolfo Carosi |
| collection | DOAJ |
| description | Detailed geological field mapping, integrated with meso- and microstructural investigations, kinematic of the flow and finite strain analyses, combined with geochronology, are fundamental tools to obtain information on the temperature–deformation–timing path of crystalline rocks and shear zone. The Posada-Asinara shear zone (PASZ) in northern Sardinia (Italy) is a steeply dipping km-thick transpressive shear zone. In the study area, located in the Baronie region (NE Sardinia), the presence of mylonites within the PASZ, affecting high- and medium-grade metamorphic rocks, provides an opportunity to quantify finite strain and kinematic vorticity. The main structures of the study area are controlled by a D<sub>2</sub> deformation phase, linked to the PASZ activity, in which the strain is partitioned into folds and shear zone domains. Applying two independent vorticity methods, we detected an important variation in the percentage of pure shear and simple shear along the deformation gradient, that increases from south to north. We constrained, for the first time in this sector, the timing of the transpressive deformation by U–(Th)–Pb analysis on monazite. Results indicate that the shear zone has been active at ~325–300 Ma in a transpressive setting, in agreement with the ages of the other dextral transpressive shear zones in the southern Variscan belt. |
| first_indexed | 2024-03-10T18:08:28Z |
| format | Article |
| id | doaj.art-bdb10bb8bf8c4bd6ad6ccc0410fa1334 |
| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-03-10T18:08:28Z |
| publishDate | 2020-07-01 |
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| record_format | Article |
| series | Geosciences |
| spelling | doaj.art-bdb10bb8bf8c4bd6ad6ccc0410fa13342023-11-20T08:22:24ZengMDPI AGGeosciences2076-32632020-07-0110828810.3390/geosciences10080288Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy)Rodolfo Carosi0Alessandro Petroccia1Salvatore Iaccarino2Matteo Simonetti3Antonio Langone4Chiara Montomoli5Department of Earth Sciences, University of Turin, Via Valperga Caluso 35, 10125 Torino, ItalyDepartment of Earth Sciences, University of Turin, Via Valperga Caluso 35, 10125 Torino, ItalyDepartment of Earth Sciences, University of Turin, Via Valperga Caluso 35, 10125 Torino, ItalyDepartment of Earth Sciences, University of Turin, Via Valperga Caluso 35, 10125 Torino, ItalyIGG-CNR Pavia, Via Ferrata 1, 27100 Pavia, ItalyDepartment of Earth Sciences, University of Turin, Via Valperga Caluso 35, 10125 Torino, ItalyDetailed geological field mapping, integrated with meso- and microstructural investigations, kinematic of the flow and finite strain analyses, combined with geochronology, are fundamental tools to obtain information on the temperature–deformation–timing path of crystalline rocks and shear zone. The Posada-Asinara shear zone (PASZ) in northern Sardinia (Italy) is a steeply dipping km-thick transpressive shear zone. In the study area, located in the Baronie region (NE Sardinia), the presence of mylonites within the PASZ, affecting high- and medium-grade metamorphic rocks, provides an opportunity to quantify finite strain and kinematic vorticity. The main structures of the study area are controlled by a D<sub>2</sub> deformation phase, linked to the PASZ activity, in which the strain is partitioned into folds and shear zone domains. Applying two independent vorticity methods, we detected an important variation in the percentage of pure shear and simple shear along the deformation gradient, that increases from south to north. We constrained, for the first time in this sector, the timing of the transpressive deformation by U–(Th)–Pb analysis on monazite. Results indicate that the shear zone has been active at ~325–300 Ma in a transpressive setting, in agreement with the ages of the other dextral transpressive shear zones in the southern Variscan belt.https://www.mdpi.com/2076-3263/10/8/288Sardinian basementtranspressionstrain partitioningvorticityin situ monazite geochronology |
| spellingShingle | Rodolfo Carosi Alessandro Petroccia Salvatore Iaccarino Matteo Simonetti Antonio Langone Chiara Montomoli Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy) Geosciences Sardinian basement transpression strain partitioning vorticity in situ monazite geochronology |
| title | Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy) |
| title_full | Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy) |
| title_fullStr | Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy) |
| title_full_unstemmed | Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy) |
| title_short | Kinematics and Timing Constraints in a Transpressive Tectonic Regime: The Example of the Posada-Asinara Shear Zone (NE Sardinia, Italy) |
| title_sort | kinematics and timing constraints in a transpressive tectonic regime the example of the posada asinara shear zone ne sardinia italy |
| topic | Sardinian basement transpression strain partitioning vorticity in situ monazite geochronology |
| url | https://www.mdpi.com/2076-3263/10/8/288 |
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