Structure of the Pennine Zone (Central Alps): A New Working Hypothesis

Abstract

Research Article| November 01, 1974 Structure of the Pennine Zone (Central Alps): A New Working Hypothesis A. G. MILNES A. G. MILNES 1Geologisches Institut, Eidgenössische Technische Hochschule und Universitädt, Zürich, Switzerland Search for other works by this author on: GSW Google Scholar GSA Bulletin (1974) 85 (11): 1727–1732. https://doi.org/10.1130/0016-7606(1974)85<1727:SOTPZC>2.0.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 A. G. MILNES; Structure of the Pennine Zone (Central Alps): A New Working Hypothesis. GSA Bulletin 1974;; 85 (11): 1727–1732. doi: https://doi.org/10.1130/0016-7606(1974)85<1727:SOTPZC>2.0.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 discovery and preliminary mapping of large recumbent fold structures in the Pennine zone of the Central Alps (Switzerland and Italy) justifies a review of the overall structure of this zone. For descriptive purposes, the zone is subdivided into an Upper Pennine and a Lower Pennine complex, defined roughly as in earlier literature. Below these, a “Subpennine” complex, which includes the Gotthard massif, is recognized. The complexes consist of a “nappe structure” — interleaved or intermixed pre-Triassic basement and Mesozoic cover units (nappes), already showing a complicated history of thrusting, intense folding, and imbrication or even formation of tectonic mélanges — affected by later (“postnappe”) recumbent folding on a regional scale. In an even later phase of deformation, the “root zones” developed. These are referred to as steep belts, because the implied genetic connection of “roots” to nappe formation can no longer be upheld. Paleogeographic reconstruction of the Pennine realm depends on a correct “unfolding” of these fold phases. This is not yet possible for the postnappe recumbent folds, first because they have not yet been completely mapped, and second because reliable criteria for deciding how the nappe structure lay before folding are not yet available. Plate tectonic interpretation of the Pennine zone, which contains the only ophiolite complexes in the Alps, will depend to some extent on a clarification of regional relations on the basis of this newly emerging structural picture. 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.