Kinematics of Jurassic rifting, mantle exhumation, and passive-margin formation in the Austroalpine and Penninic nappes (eastern Switzerland)

Abstract

Research Article| September 01, 1996 Kinematics of Jurassic rifting, mantle exhumation, and passive-margin formation in the Austroalpine and Penninic nappes (eastern Switzerland) Nikolaus Froitzheim; Nikolaus Froitzheim 1Geologisch-Paläontologisches Institut, Universität Basel, Bernoullistrasse 32, CH-4056 Basel, Switzerland Search for other works by this author on: GSW Google Scholar Gianreto Manatschal Gianreto Manatschal 2Geologisches Institut, ETH-Zentrum, CH-8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information Nikolaus Froitzheim 1Geologisch-Paläontologisches Institut, Universität Basel, Bernoullistrasse 32, CH-4056 Basel, Switzerland Gianreto Manatschal 2Geologisches Institut, ETH-Zentrum, CH-8092 Zürich, Switzerland Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1996) 108 (9): 1120–1133. https://doi.org/10.1130/0016-7606(1996)108<1120:KOJRME>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Nikolaus Froitzheim, Gianreto Manatschal; Kinematics of Jurassic rifting, mantle exhumation, and passive-margin formation in the Austroalpine and Penninic nappes (eastern Switzerland). GSA Bulletin 1996;; 108 (9): 1120–1133. doi: https://doi.org/10.1130/0016-7606(1996)108<1120:KOJRME>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Austroalpine and Upper Penninic nappes in eastern Switzerland represent a passive continental margin and the adjacent ocean of Jurassic-Cretaceous age, imbricated by Late Cretaceous-Tertiary orogenic shortening. Well-preserved, rift-related faults allow reconstruction of the passive margin and ocean-continent transition zone and yield new information on the kinematics of rifting. Rifting evolved from pure-shear stretching to detachment-controlled, asymmetric stretching and resulted in complete exhumation of subcontinental mantle rocks at the sea floor.After precursory normal faulting in the Late Triassic, Jurassic rifting occurred in two phases. During the first rifting phase (Hettangian-Sinemurian), predominantly east-dipping normal faults developed in the upper crust; their dips decreased in the middle to lower crust, where they probably graded into anastomosing shear zones in the lower crust and mantle lithosphere. The resulting overall geometry approximated pure-shear stretching. During the second rifting phase (Toarcian-Middle Jurassic), a system of west-dipping detachment faults formed, penetrating the whole lithosphere and accommodating asymmetric extension. During progressive stretching, subcontinental mantle rocks were tectonically exhumed and exposed at the sea floor in two areas, represented by the Platta and Malenco nappes (Penninic). The intervening Margna and Sella continental nappes are interpreted as an extensional allochthon belonging to the Apulian margin. Finally, a mid-ocean ridge may have formed west of the Margna-Sella allochthon. The Austroalpine realm thus represents the lower-plate margin—and the Briançonnais, the upper-plate margin-of the Piemont-Liguria ocean. This scenario is in qualitative agreement with the subsidence histories of the two margins. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.