A sequence of regional deformation episodes is described in the Permian cover and in the metamorphic basement of a portion of the Southern Alps, southeast of Sondrio (Valtellina). The earliest episode is contemporaneous with low to medium grade metamorphism in the basement; the second episode occurs during low temperature greenschist-facies retrogradation in the basement; these two synmetamorphic regional deformation episodes in the basement are pre-Alpine (probably of Variscan age) and predate the deposition of Permian sediments. Cover and basement are deformed together during a third tectonic episoide of post-Triassic age, unrelated to regional metamorphic reactivation, and associated with nappe emplacment and regional folding, that took place at shallow levels of the Southalpine margin during Alpine time. -Authors
Alpine and pre-Alpine tectonics in the Central Orobic Alps (Southern Alps) / P.F. Milano, G. Pennacchioni, M.I. Spalla. - In: ECLOGAE GEOLOGICAE HELVETIAE. - ISSN 0012-9402. - 81:2(1988), pp. 273-293.
Alpine and pre-Alpine tectonics in the Central Orobic Alps (Southern Alps)
M.I. SpallaUltimo
1988
Abstract
A sequence of regional deformation episodes is described in the Permian cover and in the metamorphic basement of a portion of the Southern Alps, southeast of Sondrio (Valtellina). The earliest episode is contemporaneous with low to medium grade metamorphism in the basement; the second episode occurs during low temperature greenschist-facies retrogradation in the basement; these two synmetamorphic regional deformation episodes in the basement are pre-Alpine (probably of Variscan age) and predate the deposition of Permian sediments. Cover and basement are deformed together during a third tectonic episoide of post-Triassic age, unrelated to regional metamorphic reactivation, and associated with nappe emplacment and regional folding, that took place at shallow levels of the Southalpine margin during Alpine time. -AuthorsPubblicazioni consigliate
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