Miocene postorogenic extension of the Eocene synorogenic imbricated Hellenic subduction channel: New constraints from Milos (Cyclades, Greece)

Research Article| August 31, 2017 Miocene postorogenic extension of the Eocene synorogenic imbricated Hellenic subduction channel: New constraints from Milos (Cyclades, Greece) Bernhard Grasemann; Bernhard Grasemann † 1Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria †bernhard.graseman@univie.ac.at Search for other works by this author on: GSW Google Scholar Benjamin Huet; Benjamin Huet 1Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria Search for other works by this author on: GSW Google Scholar David A. Schneider; David A. Schneider 2Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada Search for other works by this author on: GSW Google Scholar A. Hugh N. Rice; A. Hugh N. Rice 1Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria Search for other works by this author on: GSW Google Scholar Nicolas Lemonnier; Nicolas Lemonnier 3Institut des Sciences de la Terre de Paris, Université Pierre et Marie Curie, 75005 Paris, France Search for other works by this author on: GSW Google Scholar Cornelius Tschegg Cornelius Tschegg 4Department of Lithospheric Research, University of Vienna, A-1090 Vienna, Austria Search for other works by this author on: GSW Google Scholar Author and Article Information Bernhard Grasemann † 1Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria Benjamin Huet 1Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria David A. Schneider 2Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada A. Hugh N. Rice 1Department of Geodynamics and Sedimentology, University of Vienna, A-1090 Vienna, Austria Nicolas Lemonnier 3Institut des Sciences de la Terre de Paris, Université Pierre et Marie Curie, 75005 Paris, France Cornelius Tschegg 4Department of Lithospheric Research, University of Vienna, A-1090 Vienna, Austria †bernhard.graseman@univie.ac.at Publisher: Geological Society of America Received: 28 Dec 2016 Revision Received: 14 May 2017 Accepted: 03 Jul 2017 First Online: 31 Aug 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2017 Geological Society of America GSA Bulletin (2018) 130 (1-2): 238–262. https://doi.org/10.1130/B31731.1 Article history Received: 28 Dec 2016 Revision Received: 14 May 2017 Accepted: 03 Jul 2017 First Online: 31 Aug 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Bernhard Grasemann, Benjamin Huet, David A. Schneider, A. Hugh N. Rice, Nicolas Lemonnier, Cornelius Tschegg; Miocene postorogenic extension of the Eocene synorogenic imbricated Hellenic subduction channel: New constraints from Milos (Cyclades, Greece). GSA Bulletin 2017;; 130 (1-2): 238–262. doi: https://doi.org/10.1130/B31731.1 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 island of Milos is part of the South Aegean volcanic arc. The volcanic processes on Milos, which started ca. 3.5 Ma, have been studied in detail, but the limited outcrops of basement rocks have not yet been adequately investigated. We present new structural, petrological, and geochronological data that suggest that the basement rocks on Milos (Kiriaki complex) belong to the Cycladic Blueschist Unit, which underwent blueschist metamorphism at ∼8.5 kbar and 400 °C. The complex experienced pervasive ductile deformation in the Paleocene–Eocene, with top-to-the-S to -SW shearing. Recalculation of published data from eclogite pebbles that occur as detrital products in "Green Lahars" structurally above the Kiriaki complex yields contrasting metamorphic conditions of ∼19.5 kbar at 550 °C, suggesting that two nappes, the exposed Lower Cycladic Nappe and eroded relicts of the Upper Cycladic Nappe, exist on Milos. These nappes, which also occur on other Cycladic islands, are separated by the newly defined synorogenic Trans Cycladic thrust. Since Milos is located above the West Cycladic detachment system, the rocks escaped the postorogenic middle–late Miocene low-angled extensional overprint. While rocks in the footwall of the West Cycladic detachment system were experiencing ductile shearing, sediments were being nonconformably deposited on metamorphic rocks of the Kiriaki complex on Milos in the late Miocene. Most importantly, the postorogenic West Cycladic detachment system did not reactivate but instead crosscut synorogenic structures such as the Trans Cycladic thrust, which bends 90° at Milos, exhibiting a change from W-E– to N-S–trending stretching lineations. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.