Sedimentary fabrics in Alpine ophicalcites, South Pennine Arosa zone, Switzerland

Research Article| November 01, 1985 Sedimentary fabrics in Alpine ophicalcites, South Pennine Arosa zone, Switzerland Daniel Bernoulli; Daniel Bernoulli 1Geological Institute of the University, CH-4056, Basel, Switzerland Search for other works by this author on: GSW Google Scholar Helmut Weissert Helmut Weissert 2Geological Institute, ETH-Z, Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Geology (1985) 13 (11): 755–758. https://doi.org/10.1130/0091-7613(1985)13<755:SFIAOS>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Daniel Bernoulli, Helmut Weissert; Sedimentary fabrics in Alpine ophicalcites, South Pennine Arosa zone, Switzerland. Geology 1985;; 13 (11): 755–758. doi: https://doi.org/10.1130/0091-7613(1985)13<755:SFIAOS>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 SocietyGeology Search Advanced Search Abstract Many ultramafic complexes in the South Pennine nappes of eastern Switzerland are covered by serpentinite breccias, known as ophicalcites. The breccias are overlain by radiolarites or younger oceanic sediments. Their fabric and their components document a combined tectonic-sedimentary origin of the breccias. In the Davos area the breccias occur along distinct zones in the ultramafic host rock. Typically, nonfragmented peridotite/serpentinite grades rapidly through a narrow zone of host rock, cut by different generations of dikes, into complex breccias dominated by a carbonate matrix. The breccias are of polyphase origin, as shown by the different phases of fragmentation and generations of cementation and sediment infill. These are distinguished by color differences and by a bimodal grain-size distribution that also exhibits geopetal structures. Comparison with breccias from present-day oceanic fracture zones suggests that the Tethyan serpentinite breccias may have formed in a transform setting. A sinistral transform margin along the northern edge of the Apulian microplate or promontory is in line with current plate-kinematic reconstructions. 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.