Paleomagnetism of the Gran Sasso range salient (central Apennines, Italy): Pattern of orogenic rotations due to translation of a massive carbonate indenter

摘要: [1] We report on the paleomagnetism (39 new sites) of Gran Sasso, an indenter-controlled salient external central Apennines formed by two orthogonal limbs. We find that Sasso is a complex salient, paleomagnetically corresponding to neither nonrotating nor oroclinal end-member. Data from core arc show indenter itself did not undergo any rotation. Conversely, rotations variable magnitude and sign are observed along curve-shaped thrust fronts. Rotations virtually absent at both end points arc. Moving toward apex, progressively greater counterclockwise (CCW) clockwise (CW) occur E-W N-S fronts, respectively. The increase continuously more than linearly, reaching their maximum values (∼80° CCW ∼50° CW) around apex. Here, strongly CW rotated fronts separated domain characterized local block rotations. inequality between rotation likely consequence asymmetry displacement direction (N70°E) with respect preorogenic trends its margins (E-W N-S). From point view, close define arc, while pattern apex similar orocline. conclude points, nonrotational thrusting normal occurred, in vicinity peritidal carbonates acted as “ice breaker”, pushing apart (and rotating) weaker multilayer located ahead.