THERMOMECHANICAL MODELING OF THE TYRRHENIAN SEA - LITHOSPHERIC NECKING AND KINEMATICS OF RIFTING

We present the results of quantitative forward modeling of the Sardini an rifted margin of the Tyrrhenian Sea. The purpose of this study is t o investigate the thermomechanical structure that affects the thinning of the lithosphere across the margin. The role of lithospheric neckin g during basin formation, constrained by basement topography, Moho dep th, and gravity anomalies, is modeled for different compensation model s. Independent constraints are obtained from the analysis of the predi cted thermal structure. A deep level of necking (25 km) is required to explain the observed crustal geometries and gravity anomaly signature . The model predicts spatial and temporal variations in theology durin g extension with important implications for kinematics of lithospheric thinning. Prerift lithospheric conditions, strain rate, and temperatu re during extension appear to be the key controls on the style of lith ospheric rifting and necking in the Tyrrhenian Sea. A forward model fo r basin stratigraphy is presented for the polyphase history of the Tyr rhenian rifting. This model provides quantitative estimates of time-sp ace dependent crustal thinning and rates of extension.