An active syndepositional tectonic framework largely influenced the evolution of the Middle Triassic carbonate platforms of the Dolomites. This evolution was probably controlled by an extensional (transtentional?) tectonic regime, associated with the magmatic bulging of the area. A fast subsidence phase, enhanced by the rapidly increasing load of the aggrading platforms, was followed by a period of reduced relative sea level increase, triggering a massive platform progradation. During the initial subsidence evolution, many independent platform nuclei developed, some of them soon to be killed by an early drowning, whereas the surviving ones progressively widened. This evolution locally caused two or more distinct platforms to merge, thus generating larger edifices. At least three independent platform nuclei can be identified in the Marmolada Massif and other three in the Sciliar-Catinaccio one. The carbonate platform growth was eventually terminated by a short-lived volcanic phase, which locally mutilated the western Dolomites platforms, by inducing margin failure, calderic collapsing and magmatic stopping. The Ladinian magmatic event generated significant crustal complexity, which was to influence the Cainozoic Alpine tectonic evolution. During the major compressional phases, deformational processes largely telescoped the palaeogeographic elements and several carbonate platforms overthrusted one upon each other, as observed in the Marmolada and the Sciliar-Catinaccio areas. Strike-slip tectonics also occurred in late orogenic stages, partially disrupting and rearranging the contractional structures, thus further complicating the geometric relationships between the sedimentary bodies. Any correct understanding of the spectacular Triassic carbonate platforms of the Dolomites should be therefore grounded on a multidisciplinary approach, integrating sedimentological-stratigraphic, chronological and structural researches. The geological complexity of the region means that plenty of work is waiting for this goal to achieve.
Understanding polynucleated carbonate platforms based on palinspastic restorations: examples from the Middle Triassic of the Dolomites
CAPUTO, Riccardo;STEFANI, Marco
2003
Abstract
An active syndepositional tectonic framework largely influenced the evolution of the Middle Triassic carbonate platforms of the Dolomites. This evolution was probably controlled by an extensional (transtentional?) tectonic regime, associated with the magmatic bulging of the area. A fast subsidence phase, enhanced by the rapidly increasing load of the aggrading platforms, was followed by a period of reduced relative sea level increase, triggering a massive platform progradation. During the initial subsidence evolution, many independent platform nuclei developed, some of them soon to be killed by an early drowning, whereas the surviving ones progressively widened. This evolution locally caused two or more distinct platforms to merge, thus generating larger edifices. At least three independent platform nuclei can be identified in the Marmolada Massif and other three in the Sciliar-Catinaccio one. The carbonate platform growth was eventually terminated by a short-lived volcanic phase, which locally mutilated the western Dolomites platforms, by inducing margin failure, calderic collapsing and magmatic stopping. The Ladinian magmatic event generated significant crustal complexity, which was to influence the Cainozoic Alpine tectonic evolution. During the major compressional phases, deformational processes largely telescoped the palaeogeographic elements and several carbonate platforms overthrusted one upon each other, as observed in the Marmolada and the Sciliar-Catinaccio areas. Strike-slip tectonics also occurred in late orogenic stages, partially disrupting and rearranging the contractional structures, thus further complicating the geometric relationships between the sedimentary bodies. Any correct understanding of the spectacular Triassic carbonate platforms of the Dolomites should be therefore grounded on a multidisciplinary approach, integrating sedimentological-stratigraphic, chronological and structural researches. The geological complexity of the region means that plenty of work is waiting for this goal to achieve.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
