The Lithosphere and Upper Mantle of the Western‐Central Mediterranean Region From Integrated Geophysical‐Geochemical Modeling

• Published in: Journal of geophysical research. Solid earth Vol. 129; no. 4
• Main Authors: Zhang, Wentao, Jiménez‐Munt, Ivone, Torne, Montserrat, Vergés, Jaume, Bravo‐Gutiérrez, Estefanía, Negredo, Ana M., García‐Castellanos, Daniel
• Format: Journal Article
• Language: English
• Published: 01.04.2024
• Subjects: convergent margins; integrated geophysical‐geochemical modeling; lithospheric mantle composition; potential field and thermal data; sublithospheric thermal anomalies; thermomechanical structure of the lithosphere and sublithospheric mantle
• ISSN: 2169-9313; 2169-9356
• DOI: 10.1029/2023JB028435

This study integrates geophysical‐geochemical data to investigate the thermochemical structure of the lithosphere and sublithospheric mantle, along the Southern Tyrrhenian Basin, Apennines, Adriatic Sea, Dinarides, and Carpathians‐Balkanides. We present the lithospheric structure of the Adria microplate and the two opposing mantle slabs along its NE and SW margins. The modeling shows the presence of two asthenospheric mantle wedges aligning with the Apenninic and Dinaric continental mantle slab rollback, along with cold (−200°C) sublithospheric anomalies beneath Adria's NE and SW margins. In the northern Adria region, the lithosphere undergoes synchronous thinning in the Tyrrhenian domain and thickening toward the forefront of the northern Apennines. This is associated with the northeastward rollback of the SW Adriatic slab, leading to subsequent delamination of the continental mantle. In the southern Adria region, the complex deep structure results from the variably oriented lithospheric slabs, and nearly 90‐degree shift of the tectonic grain between the southern Apennines and the Calabrian Arc. At the SW Adria margin, beneath the northern Apennines, the thermal sublithospheric anomaly is attached to the shallower lithosphere, while a slab gap is modeled in the southern Apennines. One possibility is that the gap is due to a recent horizontal slab tear. Along the NE margin of Adria, the thermal anomaly penetrates to depths of about 200 km in the northern Dinarides and 280 km in the southern Dinarides, shallower than the SW Adria anomaly, which extends to at least 400 km depth. Plain Language Summary We integrate geological and geophysical data (e.g., elevation, gravity, geoid, seismic tomography) to investigate the density and temperature distribution of the crust and lithospheric mantle down to 400 km, along a profile that extends from the Southern Tyrrhenian Basin and Apennines in Italy to the Southern Dinarides and Carpathians‐Balkanides in southern Europe. Taking advantage of our previous research in this region, we provide an integrated view of the lithospheric structure and the uppermost mantle of the Tyrrhenian Basin, Apennines, Adriatic Sea and Dinarides. Our results show notable variations in both the crust and the base of the lithosphere. These variations are observed to be shallower beneath the basins and deeper beneath the mountain belts, particularly in areas with elevated topography. Additionally, our observations highlight the presence of two cold and dense zones situated in the distal margins of the Adria microplate, specifically beneath the Apennines and Dinarides. The thermal anomalies indicate the presence of two oppositely subducting slabs with different geometries and depth of penetration. Their current location, depth and shape have largely controlled the geodynamic evolution of the study region in the last 30 My. Key Points We unveil the thermochemical structure of the lithosphere and uppermost mantle of the Adria Microplate and its margins Results reveal mantle wedges aligning with Apenninic and Dinaric slabs, and cold sublithospheric anomalies beneath NE and SW Adria margins In N Apennines the slab is attached while a gap is observed in S Apennines. At Adria's NE margin, the slab penetrates deeper southward