Two new maps describing the Mesozoic-Cenozoic, Alpine metamorphic structure (1:1’000’000) and metamorphic ages (1:2’000’000) are presented. A short discussion of the map units used is provided to introduce some key papers summing up new ideas, lines of thought, the data used and the problems encountered.
The former northern margin of Tethis is being studied in the Alpine chain by IGCP Project 198(Evolution of the Northern Margin of the Tethys). This paper summarizes the present state of the knowlege from the opening phase of this Mesozoic to early Paleogene seaway in Eastern Switzerland. Basement rocks and sediments of the previous margin are now exposed here in the stack of the Alps and their European foreland.
Two different members of lead calcium arsenate series of apatite group from Nezilovo are found. According to the chemical formula (calculated on the basis of 10 cations), infra red absorption powder spectra, X-ray powder patterns and unit cell dimensions these are two distinct members of one mineral species. Unit cell dimensions are a=10.157(3), c=7.256(6) and a=10.154(2), c=7.191(3) A. The first sample has Pb:Ca ratio 7.35:2.59 and the second one 6.54:3.45, what is closer to ideal hedyphane formula (6:4).
In southwestern Turkey, the Lycian nappe complex which overlies the autochthonous Menderes Massif and Bey Dağ platform, consists from base to top of metasediments, a mélange unit and an ophiolitic sequence. Fresh Fe‐Mg‐carpholite occurrence in the metasediments attests to a high‐pressure low‐temperature metamorphic event. We report the distribution of Fe‐Mg‐carpholite and its breakdown products (e.g., pyrophyllite and chloritoid) on the Bodrum peninsula, south of the Menderes crystalline massif. The distribution of Fe‐Mg‐carpholite and its relics shows that the low‐grade high‐pressure metamorphism affected a widespread area in the lower units of the Lycian Nappes. Analysis of the ductile deformation in HP‐LT metasediments indicates shear senses top‐to‐the‐northeast to top‐to‐the‐east. Most of this deformation is contemporaneous with the retrogression of high‐pressure low‐temperature parageneses and is therefore coeval with exhumation from a depth of about 30 km. At the top of the Menderes Massif “cover series,” close to the contact with the Lycian Nappes, similar eastward displacements are observed and trajectories of the stretching lineations are continuous from the Lycian Nappes to the Menderes Massif across the contact. These observed movements are incompatible with the southward transport of the Lycian Nappes over the Menderes Massif. We discuss the regional tectonic implications and conclude that the Lycian Nappes and the southernmost part of the Menderes Massif were exhumed in two stages: (1) Eocene (?) top‐to‐the‐NE shear (syn‐orogenic extension?), (2) Miocene deformation contemporaneous with the Aegean extension.
Research Article| December 01, 1998 Late thermal evolution of the Oman Mountains subophiolitic windows: Apatite fission-track thermochronology Gérard Poupeau; Gérard Poupeau 1UPRES-A 5025 CNRS, Université Joseph Fourier, 15 rue Maurice Gignoux, 38031 Grenoble, France Search for other works by this author on: GSW Google Scholar Omar Saddiqi; Omar Saddiqi 2Université Hassan II, Faculté des Sciences Aïn Chok, Département de Géologie, BP 5366 Mâarif, Casablanca, Morocco Search for other works by this author on: GSW Google Scholar André Michard; André Michard 3Ecole Normale Supérieure, Laboratoire de Géologie, URA 1316 CNRS, 24 rue Lhomond, 75231 Paris Cedex 05, France Search for other works by this author on: GSW Google Scholar Bruno Goffé; Bruno Goffé 3Ecole Normale Supérieure, Laboratoire de Géologie, URA 1316 CNRS, 24 rue Lhomond, 75231 Paris Cedex 05, France Search for other works by this author on: GSW Google Scholar Roland Oberhänsli Roland Oberhänsli 4Institut fur Geowissenschaften, Universität Potsdam, Postfach 601553, D-14415 Potsdam, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Gérard Poupeau 1UPRES-A 5025 CNRS, Université Joseph Fourier, 15 rue Maurice Gignoux, 38031 Grenoble, France Omar Saddiqi 2Université Hassan II, Faculté des Sciences Aïn Chok, Département de Géologie, BP 5366 Mâarif, Casablanca, Morocco André Michard 3Ecole Normale Supérieure, Laboratoire de Géologie, URA 1316 CNRS, 24 rue Lhomond, 75231 Paris Cedex 05, France Bruno Goffé 3Ecole Normale Supérieure, Laboratoire de Géologie, URA 1316 CNRS, 24 rue Lhomond, 75231 Paris Cedex 05, France Roland Oberhänsli 4Institut fur Geowissenschaften, Universität Potsdam, Postfach 601553, D-14415 Potsdam, Germany Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (12): 1139–1142. https://doi.org/10.1130/0091-7613(1998)026<1139:LTEOTO>2.3.CO;2 Article history First Online: 02 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 Gérard Poupeau, Omar Saddiqi, André Michard, Bruno Goffé, Roland Oberhänsli; Late thermal evolution of the Oman Mountains subophiolitic windows: Apatite fission-track thermochronology. Geology 1998;; 26 (12): 1139–1142. doi: https://doi.org/10.1130/0091-7613(1998)026<1139:LTEOTO>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 SocietyGeology Search Advanced Search Abstract In the southern Oman Mountains, high-pressure metamorphic rocks of continental origin crop out beneath the Cretaceous Samail ophiolitic nappe. We collected 14 samples from 15 to 1200 m above sea level and at various structural levels that show apatite fission-track ages between 40 ± 7 and 55 ± 5 Ma. The mean confined track lengths vary from 13.08 to 13.70 µm. Fission-track data optimization shows that the subophiolitic units cooled slowly below 60 °C at ca. 53 Ma, then remained at low temperature until ca. 19 Ma, i.e., during the weak postorogenic subsidence of the obduction belt. The subophiolitic basement was reheated to ∼70–80 °C at ca. 7–4 Ma, before final cooling. The reheating event is correlated with the late Miocene–Pliocene (Zagros) compressional phase. Post-Oligocene heating up to 80 °C is also documented by stable isotope study of the post-nappe Eocene-Oligocene onlap. Both the Paleocene and the Pliocene-Quaternary denudation rates are close to 0.3 mm/yr, and compatible with isostatically assisted erosion processes. 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.
