{"id":30378,"date":"2023-08-08T10:51:14","date_gmt":"2023-08-08T08:51:14","guid":{"rendered":"https:\/\/geostudio.ch\/?page_id=30378"},"modified":"2023-08-10T18:59:42","modified_gmt":"2023-08-10T16:59:42","slug":"la-geologia-della-greina","status":"publish","type":"page","link":"https:\/\/geostudio.ch\/en\/home\/blog\/la-geologia-della-greina\/","title":{"rendered":"The Geology of the Greina Mountains"},"content":{"rendered":"<div data-elementor-type=\"wp-page\" data-elementor-id=\"30378\" class=\"elementor elementor-30378\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-609aea6 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"609aea6\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-89ba8a8\" data-id=\"89ba8a8\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-b074616 elementor-widget elementor-widget-image\" data-id=\"b074616\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-scaled.jpeg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Piz Medel\" data-elementor-lightbox-description=\"Vista sul Piz Medel da Crap la Crusch\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MzAzODAsInVybCI6Imh0dHBzOlwvXC9nZW9zdHVkaW8uY2hcL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjNcLzA4XC9JTUdfMjQ1MC1zY2FsZWQuanBlZyJ9\">\n\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-1024x683.jpeg\" class=\"attachment-large size-large wp-image-30380\" alt=\"Piano della Greina - vista sul Medel e gli scisti Giurassici del Piz Coroi\" srcset=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-1024x683.jpeg 1024w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-300x200.jpeg 300w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-768x512.jpeg 768w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-1536x1024.jpeg 1536w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-2048x1365.jpeg 2048w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-18x12.jpeg 18w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_2450-800x533.jpeg 800w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-562061a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"562061a\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-f788afc\" data-id=\"f788afc\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-32e09a5 elementor-widget elementor-widget-text-editor\" data-id=\"32e09a5\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>The Greina Tour (Greina Ebene) is one of the most classic hiking trails in Ticino. With this short text we want to accompany the hiker on his journey with a story on the geological nature of the rocks encountered.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-06b786f elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"06b786f\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-544924c\" data-id=\"544924c\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-dc3c4ae elementor-widget elementor-widget-text-editor\" data-id=\"dc3c4ae\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>For those wishing to learn more about the subject, an excellent cartographic base is offered by the <span style=\"text-decoration: underline;\"><a href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1,1&amp;layers_visibility=false,false,false,false,false,false,true&amp;layers_timestamp=18641231,,,,,,&amp;E=2715199.30&amp;N=1162720.77&amp;zoom=7\" target=\"_blank\" rel=\"noopener\">Sheet 136 Greina of the Swiss Geological Atlas<\/a><\/span>, while detailed information can be found in the works of <span style=\"text-decoration: underline;\"><a title=\"Die Sedimentbedeckung des Gotthard-Massivs zwischen oberen Bleniotal und Lugnez\" href=\"https:\/\/www.e-periodica.ch\/digbib\/view?pid=egh-001%3A1961%3A54%3A%3A5#526\" target=\"_blank\" rel=\"noopener\">Baumer<\/a><\/span> et al. (1961), <a title=\"Die Mesozoischen Sedimente am S\u00fcdostrand des Gotthard-Massivs (zwischen Plaun la Greina und Versan)\" href=\"https:\/\/www.e-periodica.ch\/digbib\/view?pid=egh-001%3A1963%3A56%3A%3A1645#724\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Jung<\/span><\/a> (1963), <a title=\"Geologische der Gotthardmassivisch-penninischen Grenzregion im oberen Bleniotal Geologie der Blenio-Kraftwerke\" href=\"https:\/\/shop.swisstopo.admin.ch\/de\/buecher-und-publikationen\/landesgeologie\/beitraege-zur-geologie-der-schweiz\/geotechnische-serie\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Baumer<\/span><\/a> (1964, GS-39), <a title=\"Geologie des Greinagebietes\" href=\"https:\/\/shop.swisstopo.admin.ch\/de\/buecher-und-publikationen\/landesgeologie\/beitraege-zur-geologischen-karte-der-schweiz\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Frey<\/span><\/a> (1967, NF-131), <a title=\"Structural studies of the Rhin Valley and Lukmanier Region and their importance for the Nappe Structure of the Central Alps\" href=\"https:\/\/www.e-periodica.ch\/digbib\/view?pid=smp-001%3A1976%3A56%3A%3A180#643\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Voll<\/span><\/a> (1976), <a title=\"Geologie auf der Lugnezer Seite der Piz Aul-Gruppe\" href=\"https:\/\/www.e-periodica.ch\/digbib\/view?pid=egh-001%3A1977%3A70%3A%3A6#20\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Kupferschmid<\/span><\/a> (1977), <a title=\"L'intrusif Medel Cristallina (massif du Gothard oriental). partie 1: deformations alpines et relations socle-couverture\" href=\"https:\/\/www.e-periodica.ch\/digbib\/view?pid=smp-001%3A1989%3A69%3A%3A5#64\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Merz<\/span><\/a> (1989), <a title=\"Stratigraphische und strukturgeologische Untersuchungen im gotthardmassivischen Mesozoikum zwischen dem Lukmanierpass und der Gegend von Ilanz\" href=\"https:\/\/books.google.ch\/books\/about\/Stratigraphische_und_strukturgeologische.html?id=froaNAEACAAJ&amp;redir_esc=y\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Etter<\/span><\/a> (1987), <a title=\"Die nordpenninischen B\u00fcndnerschiefer der Zentralalpen Graub\u00fcndens\" href=\"https:\/\/www.research-collection.ethz.ch\/handle\/20.500.11850\/141666\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Steinmann<\/span><\/a> (1994),\u00a0 <a title=\"From subduction to collision. a combined metamorphic, structural and geochronological study of polymetamorphic metasediments at the NE edge of the Lepontine dome (Swiss Central Alps)\" href=\"https:\/\/edoc.unibas.ch\/948\/\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Wiederkehr<\/span><\/a> (2009) and <a title=\"STRATIGRAPHIE DES ZONES DU PIZ TERRI-LUNSCHANIA ET DE SOJA, ALPES CENTRALES (SUISSE)\" href=\"https:\/\/www.researchgate.net\/profile\/Federico-Galster\/publication\/265510417_Stratigraphie_des_zones_du_Piz_Terri-Lusnchania_et_de_Soja_Alpes_Centrales_Suisse\/links\/5416d2430cf2bb7347db7505\/Stratigraphie-des-zones-du-Piz-Terri-Lusnchania-et-de-Soja-Alpes-Centrales-Suisse.pdf\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Galster<\/span><\/a> <span style=\"text-decoration: underline;\">(2010a<\/span>, <a title=\"The Soja and Luzzone-Terri nappes: discovery of a Brian\u00e7onnais element below the front of the Adula nappe (NE Ticino, Central Alps)\" href=\"https:\/\/www.e-periodica.ch\/digbib\/view?pid=bsv-002:2010:92::242#71\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">2010<\/span><\/a><span style=\"text-decoration: underline;\">b<\/span> and <a title=\"New stratigraphic data from the Lower Penninic between the Adula nappe and the Gotthard massif and consequences for the tectonics and the paleogeography of the Central Alps\" href=\"https:\/\/serval.unil.ch\/resource\/serval:BIB_A57A4888E60A.P001\/REF.pdf\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">2012<\/span><\/a>). For any information, insights and guided excursions, you can instead contact us through <span style=\"text-decoration: underline;\"><a title=\"contacts\" href=\"https:\/\/geostudio.ch\/en\/home\/contatti\/\" target=\"_blank\" rel=\"noopener\">the form<\/a><\/span>.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-fd81466 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"fd81466\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-5e502c9\" data-id=\"5e502c9\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-df31906 elementor-widget elementor-widget-text-editor\" data-id=\"df31906\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>For practical reasons we will give up the initial portion of the route and will leave directly from the parking area under the _<span style=\"text-decoration: underline;\"><a title=\"Alpe Fontana di S. Martino\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1,1&amp;layers_visibility=false,false,false,false,false,false,false&amp;layers_timestamp=18641231,,,,,,&amp;E=2714599.72&amp;N=1160596.50&amp;zoom=9\" target=\"_blank\" rel=\"noopener\"><em>alpe di Fontana San Martino<\/em><\/a><\/span>, in the high <em>Val<\/em> <em>Camadra<\/em> and we will end at <em>diga del Luzzone (<span style=\"text-decoration: underline;\"><a href=\"https:\/\/www.touringswitzerland.com\/luzzone-dam-and-the-worlds-highest-climbing-wall\/\" target=\"_blank\" rel=\"noopener\">The Luzzone dam<\/a><\/span>). <\/em>This is because the geological formations observable during the ascent of the lower <em>Valle Camadra<\/em> they then reappear between <span style=\"text-decoration: underline;\"><a title=\"Crap la Crusch\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1,1&amp;layers_visibility=false,false,false,false,false,false,false&amp;layers_timestamp=18641231,,,,,,&amp;E=2719116.60&amp;N=1163491.74&amp;zoom=8\" target=\"_blank\" rel=\"noopener\"><em>Crap la Crusch<\/em><\/a><\/span> and Alpe di Motterascio<em>.<\/em>.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-43f631b elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"43f631b\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-60faec3\" data-id=\"60faec3\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-aa94424 elementor-widget elementor-widget-text-editor\" data-id=\"aa94424\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h1><strong>High Val Camadra - Piz Medel - Muot la Greina<\/strong><\/h1>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-6d4de48 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"6d4de48\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-e1c1907\" data-id=\"e1c1907\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3097431 elementor-widget elementor-widget-text-editor\" data-id=\"3097431\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>Along the road, just above the village of <a title=\"Daigra\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1,1&amp;layers_visibility=false,false,false,false,false,false,false&amp;layers_timestamp=18641231,,,,,,&amp;E=2714742.75&amp;N=1160186.32&amp;zoom=9\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\"><em>Daigra<\/em><\/span><\/a>, the street cross a small bridge <a href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.swissimage&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,KML%7C%7Chttps:%2F%2Fpublic.geo.admin.ch%2Fapi%2Fkml%2Ffiles%2FA7mFPD2uQKyaOjEzAjqhWA&amp;layers_opacity=1,1,1,0.8,0.8,1&amp;layers_visibility=false,false,false,false,false,true&amp;layers_timestamp=18641231,,,,,&amp;E=2714731.73&amp;N=1160426.40&amp;zoom=11.426498750721153\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">(stop here)<\/span><\/a> after which the transit is not allowed without a valid written authorization. Here, just in front of us, we have a tectonic boundary that through <a title=\"faglia del Retico\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1,1&amp;layers_visibility=false,false,false,false,false,false,true&amp;layers_timestamp=18641231,,,,,,&amp;E=2713463.93&amp;N=1160380.90&amp;zoom=8\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">the Lago Retico fault<\/span><\/a> divide the blackish pile of metasedimentary rocks to the south from the whitish gneiss of the Gotthard Massif to the north. The fault run from <em>Cima della Bianca<\/em> in <em>Val di Campo<\/em> up to the <em>Pizzo Coroi<\/em> in <em>Valle Cavalasca<\/em>. We can locate it in the trough of <em>Ri di Pr\u00fcsf\u00e0<\/em> and of <em>Ri di Sassina<\/em> respectively to the west and the east of the observer.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-174d552 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"174d552\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-3971651\" data-id=\"3971651\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-8188c0a elementor-widget elementor-widget-image\" data-id=\"8188c0a\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-scaled.jpeg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Ri di Sassina\" data-elementor-lightbox-description=\"Il solco del Ri di Sassina lungo la faglia del Retico e il contatto Scopi-Gottardo in Val Camadra.\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MzA0MjUsInVybCI6Imh0dHBzOlwvXC9nZW9zdHVkaW8uY2hcL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjNcLzA4XC9TVEg3MDcyOC1zY2FsZWQuanBlZyJ9\">\n\t\t\t\t\t\t\t<img decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-1024x768.jpeg\" class=\"attachment-large size-large wp-image-30425\" alt=\"continuazione della Faglia del Retico in Val Camadra\" srcset=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-1024x768.jpeg 1024w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-300x225.jpeg 300w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-768x576.jpeg 768w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-1536x1152.jpeg 1536w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-2048x1536.jpeg 2048w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-16x12.jpeg 16w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-800x600.jpeg 800w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70728-400x300.jpeg 400w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-8bf0b0a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"8bf0b0a\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-b76f4b6\" data-id=\"b76f4b6\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-947ecf4 elementor-widget elementor-widget-text-editor\" data-id=\"947ecf4\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>The limit today appears very clear-cut, but it should be noted that its history has actually been a little more complex. The sedimentary formations to the south came to rest with a sliding movement towards the northwest on the Gotthard \"massif\". The tectonic thrust originally must have been somewhat horizontal or slightly sloping towards the southeast, but later orogenic movements first could fold it and then steepen it bringing it locally to be almost vertical or even to lean towards the north. Eventually the contact was resumed and remobilised by the current Lago Retico fault.<\/h2><h2>The total distance accomodated by the movement of the sedimentary pile to come to rest on the Gotthard \"massif\" is not known and, depending on the school of thought, varies from a maximum of a few kilometers to a few tens of kilometers. We will take up the question again towards the end of the tour, when we will arrive in the Motterascio area <em>.<\/em>For now we simply need to keep in mind that in crossing the <em>Ri di Pr\u00fcsf\u00e0<\/em> we enter the tectonic unit classically called \"Gotthard massif\". We should also keep in mind that the contact between the rocks to the south with the rock to the north, which today seems so united, is not primary at all but is the consequence of the Alpine tectonics and the relative movements between huge rock masses (tectonic units or nappes).<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-7127f82 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7127f82\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-63698e2\" data-id=\"63698e2\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-85a2391 elementor-widget elementor-widget-text-editor\" data-id=\"85a2391\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p><strong>The Gotthard unit<\/strong><\/p><h2>The rocks of the Gotthard \"massif\" will be with us up to <em>Pian Geirett<\/em> and then up, along the <em>Brenno della Greina<\/em>\u00a0first and the the <em>Rhein da Sumvigt<\/em> then, up to <em>Crap la Crusch<\/em>, where turning south we will leave them behind us.<\/h2><h2>If, however, finding ourself between<em>Alpe di Camadra di fuori <\/em>(1745 asl) and <em>Pian Geirett<\/em> we turn our view eastwards, towards the eastern side of the valley, then we find again the blackish rocks that we had left behind crossing the <em>Ri di Pr\u00fcsf\u00e0<\/em>These rocks lie <span style=\"text-decoration: underline;\"><a title=\"sassina e marumo\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas,KML%7C%7Chttps:%2F%2Fpublic.geo.admin.ch%2Fapi%2Fkml%2Ffiles%2FG88IgHzjRF-KxlXrY2B0Tw&amp;layers_opacity=1,1,1,0.8,0.8,1,1,1&amp;layers_visibility=false,false,false,false,false,false,true,true&amp;layers_timestamp=18641231,,,,,,,&amp;E=2715107.48&amp;N=1162154.24&amp;zoom=9\" target=\"_blank\" rel=\"noopener\">the slopes of<\/a> <em>Sassina<\/em> and <em>Marumo<\/em> above 2000 asl<\/span> where between the cobbles and the pastures we can see a sharply contrasting line with black rocks above and a yellowish band below. This is the exact same tectonic contact seen at the start, but here without the late disturbance of the Lago Retico fault. Now it is oriented northward with an angle that is sometimes horizontal but generally sloping from south to north.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-c11cc6a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"c11cc6a\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-ecdff2b\" data-id=\"ecdff2b\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-27fb6f0 elementor-widget elementor-widget-image\" data-id=\"27fb6f0\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-scaled.jpeg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Contatto Scopi-Gottardo\" data-elementor-lightbox-description=\"Pendici del Marumo con il contatto tettonico fra Scopi e Gottardo e il passaggio stratigrafico dallo zoccolo ai sedimenti triassici\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MzA0MTAsInVybCI6Imh0dHBzOlwvXC9nZW9zdHVkaW8uY2hcL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjNcLzA4XC9TVEg3MDczMi0yLXNjYWxlZC5qcGVnIn0%3D\">\n\t\t\t\t\t\t\t<img decoding=\"async\" width=\"1024\" height=\"585\" src=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-1024x585.jpeg\" class=\"attachment-large size-large wp-image-30410\" alt=\"Contatto fra gneiss Paleozoici e arcosi triassiche\" srcset=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-1024x585.jpeg 1024w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-300x171.jpeg 300w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-768x439.jpeg 768w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-1536x877.jpeg 1536w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-2048x1170.jpeg 2048w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-18x10.jpeg 18w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70732-2-800x457.jpeg 800w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-9f69ca8 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"9f69ca8\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-d02881e\" data-id=\"d02881e\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-7b944c9 elementor-widget elementor-widget-text-editor\" data-id=\"7b944c9\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>Above the contact we can see the Jurassic rocks of the <span style=\"text-decoration: underline;\"><a title=\"Scopi unit\" href=\"https:\/\/www.strati.ch\/it\/tectonic\/scopi-1\/scopi-decke\" target=\"_blank\" rel=\"noopener\">Scopi unit.<\/a><\/span> These, unlike the Gotthard rocks below, lie with their youngest portion at the bottom of the pile, which support the tectonic nature of the contact. Instead below we can see  some <a title=\"Dolomia\" href=\"https:\/\/it.wikipedia.org\/wiki\/Dolomia\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">dolomites<\/span><\/a>\u00a0and some white sandstones<a title=\"Arcose\" href=\"https:\/\/it.wikipedia.org\/wiki\/Arcose\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Arkosis<\/span><\/a>presumably Triassic (from 250 to 200 millions of years ago or simply Ma) and resting directly above the Gotthard <span style=\"text-decoration: underline;\"><a title=\"Gneiss\" href=\"https:\/\/it.wikipedia.org\/wiki\/Gneiss\" target=\"_blank\" rel=\"noopener\">gneiss<\/a><\/span> which in turn are much older (in this case we are dealing with the so-called <a title=\"Streifengneiss\" href=\"https:\/\/www.strati.ch\/it\/stratigraphic\/streifengneis-komplex-gotthard\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Streifengneiss<\/span><\/a> dated at 450-430 Ma). The contact between the arkosis and the gneiss is absolutely stratigraphic and it represents one of the most revolutionary events in the geological history of the alpine region: the Triassic basal <a title=\"Trasgressione marina\" href=\"https:\/\/it.wikipedia.org\/wiki\/Trasgressione_marina\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">transgression<\/span><\/a> .<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-ef6262e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"ef6262e\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-1628d10\" data-id=\"1628d10\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3081b63 elementor-widget elementor-widget-text-editor\" data-id=\"3081b63\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>The Gotthard gneisses have a very old origin and most of them underwent at least one orogenic cycle before the Alpine one. In the lower Carboniferous (360-318 Ma), in fact, a mountain range was erected prior to the Alps and belonged to the Variscan cycle (also called Hercynian) of which we find traces especially in France, Germany and the Czech Republic. In the late Carboniferous and in the Permian (300-250 Ma) this mountain range went against a real collapse and, in the future Alpine zone, it gave way to a <a title=\"Penepiano\" href=\"https:\/\/www.treccani.it\/enciclopedia\/penepiano\/\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">peneplain<\/span><\/a>. At the end of the Permian and during the Triassic the plains were flooded which allowed the formation of sedimentary deposits in the form of quartzite and arkose sandstones first and then of dolomites with evaporites. The typology of the deposits demonstrates how the environmental conditions were comparable to vast expanses in arid areas and affected by more or less persistent marine flooding, but always characterized by a very limited water column. In classical Alpine literature this type of stratigraphy is called the \"Trias Germanique r\u00e9duit\" (<a title=\"Gignoux\" href=\"https:\/\/books.google.ch\/books\/about\/G\u00e9ologie_stratigraphique.html?id=pYVlugEACAAJ&amp;redir_esc=y\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Gignoux, 1950<\/span><\/a>) and we can find it alongside an almost mythological geological entity that has been proposed as the southwestern extensions of the <a title=\"Massiccio Boemo\" href=\"https:\/\/it.wikipedia.org\/wiki\/Massiccio_Boemo\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Bohemian Massif<\/span><\/a> (Czeck Republic) that has been named the \"Seuil Vindelicien\" (Vindelician threshold). Around the threshold marine condition where more persistent and the subsidence rate was higher, which gave rise to the Muschelkak see to the north and to the Alpine sea to the south and east. The existence of the Vindelician threshold, of which the Gotthard and neighboring units must have been a sort of southern promontory, is supported by the contrast of facies and fauna between the two seas (<a title=\"Ricour\" href=\"https:\/\/www.abebooks.com\/propos-cha\u00eene-vind\u00e9licienne-EXTRAIT-COMPTE-RENDU\/30567702143\/bd\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Ricour, 1952<\/span><\/a>). Today's examples of similar sedimentation can be found in the Sabkhah of the Persian Gulf, the Dead Sea, parts of the Sahara and Namib deserts.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-c464685 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"c464685\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-a434fe2\" data-id=\"a434fe2\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-b2c2673 elementor-widget elementor-widget-image\" data-id=\"b2c2673\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-scaled.jpeg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Gneiss e Trias del Gottardo\" data-elementor-lightbox-description=\"sovrascorrimento dell&#039;unit\u00e0 di Scopi sul &quot;massiccio&quot; del Gottardo .\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MzA0MTQsInVybCI6Imh0dHBzOlwvXC9nZW9zdHVkaW8uY2hcL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjNcLzA4XC9TVEg3MDcyNS1zY2FsZWQuanBlZyJ9\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-1024x768.jpeg\" class=\"attachment-large size-large wp-image-30414\" alt=\"sovrascorrimento dell&#039;unit\u00e0 di Scopi sul &quot;massiccio&quot; del Gottardo .\" srcset=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-1024x768.jpeg 1024w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-300x225.jpeg 300w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-768x576.jpeg 768w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-1536x1152.jpeg 1536w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-2048x1536.jpeg 2048w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-16x12.jpeg 16w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-800x600.jpeg 800w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/STH70725-400x300.jpeg 400w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-7f937b7 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7f937b7\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-d6d521a\" data-id=\"d6d521a\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-ca3196a elementor-widget elementor-widget-text-editor\" data-id=\"ca3196a\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>Below the arkosis, down the the river <em>Brenno<\/em> and up again until us and then higher to the <em>Pass d\u2019Uffiern<\/em> and up to the <em>Cima di Camadra<\/em>, instead we find the already mentioned Streifengneiss. These are rocks of magmatic origin which intruded within a metamorphic complex in the late Ordovician (460-445 Ma) and early Silurian (up to 440 Ma). Today the Streifengneisses appear as rocks with light bands composed of elongated vermiculi of quartz and feldspar in a micaceous matrix. This is mainly the result of the deformation experienced during the Variscan cycle in the Carboniferous epoch (see above). A beautiful Streifengneiss complex can be observed in the <a title=\"rocce montonate\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.swissimage&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.swissalti3d-reliefschattierung,ch.swisstopo.geologie-geologischer_atlas,KML%7C%7Chttps:%2F%2Fpublic.geo.admin.ch%2Fapi%2Fkml%2Ffiles%2FG88IgHzjRF-KxlXrY2B0Tw&amp;layers_opacity=1,1,1,0.8,0.8,1,1,1&amp;layers_visibility=false,false,false,false,false,false,false,false&amp;layers_timestamp=18641231,,,,,,,&amp;E=2714677.89&amp;N=1162497.43&amp;zoom=12\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">roche moutonn\u00e9e above the roadway between the beforelast hairpin bend (1950 asl) and <em>Pian Geirett<\/em>.<\/span><\/a><\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-f1da6ce elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f1da6ce\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-4f8c88e\" data-id=\"4f8c88e\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-30d86d8 elementor-widget elementor-widget-text-editor\" data-id=\"30d86d8\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>Downstream of the roadway and in the first section of the hairpin bend, we find a fine example of the metamorphic complex into which the Streifengneiss intruded. These are migmatites and micaceous gneiss with plagioclase and alkali feldspar of uncertain age but certainly comprised between the middle Ordovician to the Cambrian (540-490 Ma) and the Neoproterozoic (1000- 540 Ma).<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-8b30ea0 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"8b30ea0\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-7fd58d8\" data-id=\"7fd58d8\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-708bab2 elementor-widget elementor-widget-text-editor\" data-id=\"708bab2\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>Following the path towards the Brenno river we arrive at the white arkoses, here with quartzite sandstones and a greenish conglomerate basal part similar to the Swiss \u201cVerrucano\u201d. These are coarse debris formations, sometimes with volcanics, which locally filled the intramountain basins and grabens (depressions bordered by faults) existing mainly in the Late Carboniferous and Permian during and after the disintegration of the Variscan range. In the area of Greina the closest analogous complex is located between the_<a title=\"alp Cavel\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1&amp;layers_visibility=false,false,false,false,false,false&amp;layers_timestamp=18641231,,,,,&amp;E=2723266.50&amp;N=1169891.44&amp;zoom=7\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Alp Cavel<\/span><\/a> in Lumnezia and <a title=\"Carpet\" href=\"https:\/\/map.geo.admin.ch\/?lang=it&amp;topic=ech&amp;bgLayer=ch.swisstopo.pixelkarte-farbe&amp;layers=ch.swisstopo.zeitreihen,ch.bfs.gebaeude_wohnungs_register,ch.bav.haltestellen-oev,ch.swisstopo.swisstlm3d-wanderwege,ch.astra.wanderland-sperrungen_umleitungen,ch.swisstopo.geologie-geologischer_atlas&amp;layers_opacity=1,1,1,0.8,0.8,1&amp;layers_visibility=false,false,false,false,false,true&amp;layers_timestamp=18641231,,,,,&amp;E=2719893.11&amp;N=1167599.41&amp;zoom=8\" target=\"_blank\" rel=\"noopener\"><span style=\"text-decoration: underline;\">Carpet<\/span><\/a> in Val Sumvigt, where we can find the metarhyolite and the conglomerate of the Carpet slice (Schuppe).<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-deb8c73 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"deb8c73\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-f9da700\" data-id=\"f9da700\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1ed9826 elementor-widget elementor-widget-image\" data-id=\"1ed9826\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-scaled.jpeg\" data-elementor-open-lightbox=\"yes\" data-elementor-lightbox-title=\"Piz Gaglianera\" data-elementor-lightbox-description=\"Vista sul Gaglianera dal piano della Greina\" data-e-action-hash=\"#elementor-action%3Aaction%3Dlightbox%26settings%3DeyJpZCI6MzA0MzMsInVybCI6Imh0dHBzOlwvXC9nZW9zdHVkaW8uY2hcL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjNcLzA4XC9JTUdfMTU3OS1zY2FsZWQuanBlZyJ9\">\n\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-1024x683.jpeg\" class=\"attachment-large size-large wp-image-30433\" alt=\"Vista sul Gaglianera dal piano della Greina\" srcset=\"https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-1024x683.jpeg 1024w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-300x200.jpeg 300w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-768x512.jpeg 768w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-1536x1024.jpeg 1536w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-2048x1365.jpeg 2048w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-18x12.jpeg 18w, https:\/\/geostudio.ch\/wp-content\/uploads\/2023\/08\/IMG_1579-800x533.jpeg 800w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-d64d5bf elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"d64d5bf\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-530caa0\" data-id=\"530caa0\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-22b3165 elementor-widget elementor-widget-text-editor\" data-id=\"22b3165\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>The pathway along the Brenno takes us along the steep slopes below the Capanna Scaletta. These are partly covered by fans composed mostly of flakes and fragments of a black stone that is so reminiscent of slate. Once again we are dealing with the Jurassic schists of the Scopi unit which we will deal with later.<\/h2><h2>The steep but short climb towards altitude 2148 instead takes us back to the Gotthard unity with its dolomites, sandstones and finally the Streifengneiss. If we turn our gaze to the west we can admire the grandeur of Cogn di Camadra and the slopes occupied by the orthogneiss (gneiss deriving from magmatic rocks) of the Gotthard. These gneiss from the furrow of the Ri di Prusf\u00e0 reach, through the Sasso Lanzone and the Cento Valli, up to the Piz Medel, then continue north-east across the ridge between Piz Gaglianera and Piz da Stiarls and finally down to Muot la Greina and Camona where they suddenly break against the blackish schists of the Jurassic age, the same we met at the beginning of the tour.<\/h2><h2>The summit of Piz Valdraus, the northernmost point of Canton Ticino, is instead of a different nature and is part of the complex of the so-called Val Nalps gneisses. Also in this case we are dealing with metamorphic rocks from the Gotthard, however, not deriving from granitoids, as was the case for the Streifengneiss, but rather from rocks of sedimentary origin. For this reason and for their \"gneissic\" appearance they are classified as paragneiss. The original sedimentary rock, for which the name of protolith is used, must have been rich in volcanic intercalations of a mostly basic nature, therefore influenced by magma derived directly from the earth's mantle .<\/h2><h2>A plausible scenario for the formation of this sedimentary complex with volcanic intercalations may be that of an ocean trench near a volcanic arc, somewhat like the current Andes in South America. To reinforce this scenario we find, north of Piz Valdraus and behind Piz Vigliuts, a banded complex of amphibolite with some ultramafic lenses. The protolith of this complex most likely derives from an old portion of oceanic crust (MORB) or in any case from a magma deriving directly from the partial melting of the Earth's mantle. The most likely age for its formation is the Neoproteroic period (1000-540 Ma).<\/h2><h2>The mineralogy of the complex reveals how, before the Alpine cycle, it underwent a strong degree of metamorphism dominated first by high pressure (eclogite) and then by high temperatures (granulite-amphibolite). This places the Val Nalps complex in an ante-Alpine orogenic context for which we can think of the subduction of a portion of the oceanic crust first and then of the collision between continental plates. Radioactive isotope dating of metamorphic minerals and some magmatic bodies fixes this orogenic cycle to the early Ordovician (ca. 470 Ma).<\/h2><h2>If we compare the age of the orogenic cycle recorded in the rocks of Piz Valdraus (470 Ma) and compare it with the age of the Streifengneiss (440 Ma), we have to accept that the intense deformation of the latter cannot be linked to the same orogenic cycle of the first but must necessarily be younger. We can therefore conclude that in the Greina rocks we have evidence of three orogenic cycles:<\/h2><ul><li>One, the most severe, which took place in the lower Ordovician and is beautifully recorded in the gneisses of Val Nalps, can be observed on the summit of Piz Valdraus.<\/li><li>A second one which is testified by the intense deformation of the Streifengneiss (440 Ma) and which is absent in the granite rocks of Piz Cristallina (see below) and in the sandstones and dolomites of Val Camadra. Therefore must necessarily be ante-Alpine but younger than 440 Ma.<\/li><li>A third, the last, perhaps the least intense, is the one whose beauty we can admire. With his strength he created the Alps and in the small part of the Greina he led to the deformation of the Jurassic rocks that today we can observe upside down on the Gotthard massif.<\/li><\/ul><h2>To close the circle of this first stage, it is necessary to go back to the granitoids of Piz Cristallina, which together with those of Val Medel and the diorites of Uffiern, intrude into the metamorphic complexes of Piz Valdraus and in the Streifengneiss between the end of the Carboniferous and the early Permian (300-290 Ma). These granitoids do not show any deformation except the Alpine one, which is why the cycle that deformed the Streifengneiss has an age between 440 and 300 Ma. In other parts of the Alps this cycle, the Variscan one, could be identified in the lower Carboniferous between 360 and 318 Ma.<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-84a4e7c elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"84a4e7c\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-d9f95d4\" data-id=\"d9f95d4\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-e807425 elementor-widget elementor-widget-text-editor\" data-id=\"e807425\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p><strong>to be continued...09.08.2023<\/strong><\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-b2553da elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b2553da\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-1cffa23\" data-id=\"1cffa23\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-859e757 elementor-widget elementor-widget-text-editor\" data-id=\"859e757\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<h2>by Federico Galster, PhD<\/h2>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"<p>Il giro della Greina (Greina Ebene) \u00e8 una delle camminate pi\u00f9 classiche dell&#8217;escursionismo ticinese. Con questo breve testo vogliamo accompagnare l&#8217;escursionista nel suo viaggio con un racconto sulla natura geologica delle rocce incontrate. Per chi volesse approfondire l\u2019argomento, un\u2019ottima base cartografica \u00e8 offerta dal foglio 136 Greina dell\u2019atlante geologico nazionale, mentre informazioni dettagliate sono reperibili nei lavori di Baumer et&hellip;<\/p>","protected":false},"author":1,"featured_media":0,"parent":29545,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"footnotes":""},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/pages\/30378"}],"collection":[{"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/comments?post=30378"}],"version-history":[{"count":358,"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/pages\/30378\/revisions"}],"predecessor-version":[{"id":30902,"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/pages\/30378\/revisions\/30902"}],"up":[{"embeddable":true,"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/pages\/29545"}],"wp:attachment":[{"href":"https:\/\/geostudio.ch\/en\/wp-json\/wp\/v2\/media?parent=30378"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}