Geological setting of the southern termination of Western Alps

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• 作者：Anna d’Atri ; Fabrizio Piana ; Luca Barale…
• 刊名：International Journal of Earth Sciences
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：105
• 期：6
• 页码：1831-1858
• 全文大小：7,164 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geology
  Geophysics and Geodesy
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1437-3262
• 卷排序：105

文摘

A revision of the stratigraphic and tectonic setting of the southern termination of the Western Alps, at the junction of the Maritime Alps with the westernmost Ligurian Alps, is proposed. In response to the Alpine kinematic evolution, a number of tectonic units formed on the deformed palaeo-European continental margin and were arranged in a NW–SE striking anastomosed pattern along the north-eastern boundary of the Argentera Massif. Because these tectonic units often cut across the palaeogeographic subdivision of the Alpine literature and show only partial affinity with their distinctive stratigraphic features, new attributions are proposed. The Subbriançonnais domain is here intended as a “deformation zone”, and its tectonic units have been attributed to Dauphinois and Provençal domains; furthermore, the Eocene Alpine Foreland Basin succession has been interpreted, based on the affinity of its lithologic characters and age, as a single feature resting above all the successions of the different Mesozoic domains. The Cretaceous tectono-sedimentary evolution of the studied domains was characterized by intense tectonic controls on sedimentation inducing lateral variations of stratigraphic features and major hydrothermal phenomena. Since the early Oligocene, transpressional tectonics induced a NE–SW shortening, together with significant left-lateral movements followed by (late Oligocene–middle Miocene) right-lateral movements along E–W to SE–NW striking shear zones. This induced the juxtaposition and/or stacking of Briançonnais, Dauphinois and Ligurian tectonic units characterized by different metamorphic histories, from anchizonal to lower greenschist facies. This evolution resulted in the arrangement of the tectonostratigraphic units in a wide “transfer zone” accommodating the Oligocene WNW-ward movement of portions of the palaeo-European margin placed at the south-western termination of Western Alps and the Miocene dextral shearing along SE striking faults that bound the Argentera Massif on its NE side.KeywordsBriançonnaisProvençal and Dauphinois successionsMaritime AlpsWestern Ligurian AlpsAlpine orogen transpressionPre-Alpine tectonic inheritance