Tectonic controls on magmatism associated with continental break-up: an example from the Paran?¯Etendeka Province

In spite of extensive studies, the tectonic evolution of the most prominent geological boundary in Europe, the Trans-European Suture Zone (TESZ), remains enigmatic. End-member models are either autochthonous, requiring in situ Phanerozoic reworking of the pre-Cambrian crust, or allochthonous, including accretion of mobile Caledonian and Variscan terranes. Continentscale Variscan right-lateral displacements along the TESZ have been also postulated. A paleomagnetic study of Upper Silurian diabases from the southern part of Holy Cross Mts. (central Poland) was undertaken to test between these models. A primary characteristic magnetization was isolated in these rocks. It passes the fold test and therefore is considered to be Late Silurian in age. The corresponding pole (12°S, 340°S) is concordant with the Ludlovian segment of the apparent polar wander path for Baltica. This result does not support hypotheses about significant post-Caledonian dextral tectonic movements along the TESZ. Tectonic movements and accretion of blocks along the SW edge of Baltica must have occurred before the latest Silurian.