Fold uplift and synkinematic stratal architectures in a region of active transtensional tectonics and volcanism, eastern Tyrrhenian Sea

The detailed stratigraphic analysis of synkinematic stratal architectures p ermits the calculation of fold uplift rates and the reconstruction of fold kinematics. This approach was applied to active folds in the Bay of Pozzuol i, eastern Tyrrhenian Sea. This area features late Quaternary volcanism, sh allow magmatic intrusions, and transtensional tectonics. Seismostratigraphi c analysis of synkinematic strata is constrained by a physical correlation to an already established stratigraphic succession in the neighboring Campi Flegrei and by tephra layers in a gravity core located in Pozzuoli Bay. A stratigraphic resolution in thousands of years was established. Structural and stratigraphic analyses yield quantitative data on the timing of fold in ception, kinematics, and the amount and rates of uplift. The folds extend o ver similar to 2 km, and display a curved axial pattern and wedge-shaped pa ckages of synkinematic strata. The rate of fold uplift ranges from 1 to 20 mm/yr. The structures feature limb rotation kinematics and decreasing uplif t rates. The uplift rates and geometry of the Pozzuoli Bay folds suggest th at they are of tectonic origin and are a product of detachment folding. The ir limited longitudinal extent and arcuate axial trends are compatible with an east-trending left transtensional shear zone that was active along the eastern Tyrrhenian Sea during the late Quaternary, A relative sea-level cur ve was calculated for an anticline culminating in the city of Pozzuoli. Thi s relative sea-level curve highlights the relationship between the deformat ion timing and the genesis of related abrupt changes in sedimentary facies and erosional surfaces.