Paleocurrent Structures and Paleogeography of the Ultrahelvetic Flysch Basins, Switzerland

Research Article| May 01, 1960 PALEOCURRENT STRUCTURES AND PALEOGEOGRAPHY OF THE ULTRAHELVETIC FLYSCH BASINS, SWITZERLAND K JINGHWA HSU K JINGHWA HSU SHELL DEVELOPMENT CO., BOX 481, HOUSTON 1, TEXAS Search for other works by this author on: GSW Google Scholar GSA Bulletin (1960) 71 (5): 577–610. https://doi.org/10.1130/0016-7606(1960)71[577:PSAPOT]2.0.CO;2 Article history received: 22 Jan 1959 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation K JINGHWA HSU; PALEOCURRENT STRUCTURES AND PALEOGEOGRAPHY OF THE ULTRAHELVETIC FLYSCH BASINS, SWITZERLAND. GSA Bulletin 1960;; 71 (5): 577–610. doi: https://doi.org/10.1130/0016-7606(1960)71[577:PSAPOT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Ultrahelvetic Flysch of the Swiss Prealps ranges from Late Cretaceous to Eocene in age. It occurs as isolated outcrops which are known by various local names—Wäggital Flysch in the Glarus Alps, Schlieren Flysch in central Switzerland, Leissigen Flysch in the Internal Prealps southwest of Lake Thun, and Gurnigel Flysch in the Bernese External Prealps. These Flysch formations are characterized by thick sequences of interbedded sandstone, conglomerate, shale, and silty limestone. The sandstone of the Flysch exhibits sedimentary structures typical of turbidity-current deposition—e.g., graded bedding, flute casts, groove casts. About 400 measurements of the directional sedimentary structures were made from the various Flysch formations. Paleocurrent information thus obtained was interpreted within the framework provided by the stratigraphic and tectonic studies of alpine geologists.The major conclusions of this paper are:(1) The Ultrahelvetic Flysch basins of the central Swiss Alps were created as a result of isostatic adjustment subsequent to an episode of pre-Maestrichtian folding. During the Maestrichtian to middle Eocene time, the Ultrahelvetic region was characterized by a topography typical of block-faulted terranes. Rugged land mass adjoining deep-sea basins resulted in conditions favorable for periodic turbidity-current deposition in those basins.(2) The Schlieren Flysch, the Leissigen Flysch, and the Sandstone Flysch near Adelboden were deposited in a row of near-shore deep-sea basins just south of a shallow shelf sea where carbonates of the Helvetic facies accumulated. These Flysch formations derived their sediments from the south or southwest. They were subsequently overthrust as the nappes of the Internal Prealps.(3) The Wäggital Flysch and the Gurnigel Flysch were deposited in a row of deep-sea basins farther offshore. These were separated from the near-shore basins by an island chain which furnished sediments to both units. Subsequently, the Gurnigel Flysch was overthrust as a nappe of the External Prealps. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.