{"id":228,"date":"2023-02-27T17:31:35","date_gmt":"2023-02-27T16:31:35","guid":{"rendered":"http:\/\/ujakbls.cluster031.hosting.ovh.net\/?page_id=228"},"modified":"2023-12-16T16:14:22","modified_gmt":"2023-12-16T15:14:22","slug":"diatomites-de-combier","status":"publish","type":"page","link":"https:\/\/www.societegeolardeche.com\/index.php\/diatomites-de-combier\/","title":{"rendered":"Diatomites de Combier"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"228\" class=\"elementor elementor-228\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-2bb2768 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2bb2768\" data-element_type=\"section\" data-e-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-9d889d7\" data-id=\"9d889d7\" data-element_type=\"column\" data-e-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-d6e7c7c elementor-widget elementor-widget-heading\" data-id=\"d6e7c7c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Diatomites de Combier, 21 janvier 2023, SGA<\/h2>\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-a5b6bc3 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"a5b6bc3\" data-element_type=\"section\" data-e-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-50 elementor-top-column elementor-element elementor-element-ee8174e\" data-id=\"ee8174e\" data-element_type=\"column\" data-e-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-022dc9c elementor-widget elementor-widget-text-editor\" data-id=\"022dc9c\" data-element_type=\"widget\" data-e-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\t\t<p>Cette premi\u00e8re sortie SGA de l&rsquo;ann\u00e9e a b\u00e9n\u00e9fici\u00e9 de bonnes \u00e9claircies ensoleill\u00e9es, malgr\u00e9 un froid vif. Il y a eu 7 participants en plus de\u00a0 Daniel NARDIN qui guidait.<\/p><p>Un premier arr\u00eat \u00e0 cot\u00e9 du RDV dans la zone commerciale a permis de voir les alternances en bancs d\u00e9cim\u00e9triques de marnes et de calcaires d&rsquo;age l&rsquo;oxfordien.<br \/>Cela permet d&rsquo;\u00e9voquer les causes peut \u00eatre climatiques-astronomiques de ces alternances\u00a0 de d\u00e9p\u00f4ts plus ou moins argileux donc plus ou moins profonds. Sur un site similaire vu en sortie SGA 2022, chaque doublet marne calcaire est interpr\u00e9t\u00e9 comme correspondant \u00e0 un cycle de pr\u00e9cession des \u00e9quinoxes., d&rsquo;environs 23 0000ans.<\/p><p>100m \u00e0 l&rsquo;est,\u00a0 l&rsquo;existence d&rsquo;un affleurement de calcaires blancs d&rsquo;age kimm\u00e9rigien, non repris par la CG Privas, t\u00e9moigne d&rsquo;un abaissement du bloc \u00e0 l&rsquo;est, donc de failles dans le secteur qui d\u00e9calent en \u00ab\u00a0touche de piano\u00a0\u00bb NS le terrain\u00a0<\/p>\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<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-7e08828\" data-id=\"7e08828\" data-element_type=\"column\" data-e-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-03ef66c elementor-widget elementor-widget-image\" data-id=\"03ef66c\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/2023-01-21SGA_rdvL.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Carte de localisation du site et du circuit r\u00e9alis\u00e9 (fond IGN)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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-eb4a7f7 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"eb4a7f7\" data-element_type=\"section\" data-e-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-7d33fb4\" data-id=\"7d33fb4\" data-element_type=\"column\" data-e-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-02dc859 elementor-widget elementor-widget-text-editor\" data-id=\"02dc859\" data-element_type=\"widget\" data-e-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\t\t<p>Le 2e arr\u00eat face au ball trap de Privas montre toujours un affleurement situ\u00e9 dans les alternances de marno calcaire d&rsquo;age oxfordien.<br \/>Ils sont travers\u00e9s par un dyke basaltique rep\u00e8r\u00e9 par Andr\u00e9 Rey. <\/p>\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-61d2135 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"61d2135\" data-element_type=\"section\" data-e-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-33 elementor-top-column elementor-element elementor-element-076c02d\" data-id=\"076c02d\" data-element_type=\"column\" data-e-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-c1569ed elementor-widget elementor-widget-image\" data-id=\"c1569ed\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/JFC_SGA%2020230121dykeLeCombier1rL.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Dyke photographie Jean Fran\u00e7ois CUTTIER<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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<div class=\"elementor-column elementor-col-33 elementor-top-column elementor-element elementor-element-aa50a93\" data-id=\"aa50a93\" data-element_type=\"column\" data-e-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-bcdf424 elementor-widget elementor-widget-image\" data-id=\"bcdf424\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/AR_SGA2023-01-21_150127r.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Dyke photographie Andr\u00e9 REY<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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<div class=\"elementor-column elementor-col-33 elementor-top-column elementor-element elementor-element-4a337b8\" data-id=\"4a337b8\" data-element_type=\"column\" data-e-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-d12b68f elementor-widget elementor-widget-image\" data-id=\"d12b68f\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/JFC_SGA%2020230121dykeLeCombier3rL.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Bloc avec contact basalte du dyke\/calcaire ph. J.F. CUTTIER<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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-736785e elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"736785e\" data-element_type=\"section\" data-e-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-b021bf8\" data-id=\"b021bf8\" data-element_type=\"column\" data-e-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-a206872 elementor-widget elementor-widget-text-editor\" data-id=\"a206872\" data-element_type=\"widget\" data-e-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\t\t<p>Les murs le long du ball trap sont faits de blocs de basalte, nombreux dans le lit du ruisseau de combier qui est domin\u00e9 par les rebords du plateau basaltique du Coiron.<\/p><p>Le 3e arr\u00e8t au hameau de Combier permet de voir un tr\u00e8s gros bloc \u00e9boul\u00e9 de basalte avec une prismation visible. Les batiments sont construits tr\u00e8s majoritairement avec des blocs de basalte. Mais des encadrements de fen\u00e8tres sont en gr\u00e8s du trias taill\u00e9.<\/p><p>Au premier virage en \u00e9pingle (4) affleurent des calcaires blancs du kimm\u00e9ridgien. Nous avons donc une s\u00e9rie s\u00e9dimentaire calcaire qui s&rsquo;est form\u00e9e\u00a0 de -160 \u00e0 -150 millions d&rsquo;ann\u00e9es.<\/p>\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-f7da55c elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f7da55c\" data-element_type=\"section\" data-e-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-50 elementor-top-column elementor-element elementor-element-74e514d\" data-id=\"74e514d\" data-element_type=\"column\" data-e-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-27543b8 elementor-widget elementor-widget-image\" data-id=\"27543b8\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/JFCSGA20230121tufs1rl.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">affleurement 4, photographie Jean Fran\u00e7ois CUTTIER<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-7107813\" data-id=\"7107813\" data-element_type=\"column\" data-e-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-66dc76a elementor-widget elementor-widget-text-editor\" data-id=\"66dc76a\" data-element_type=\"widget\" data-e-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\t\t<p>Au d\u00e9part de l&rsquo;\u00e9pingle suivante (5), nous avons observ\u00e9 des tufs volcaniques ou tephras. <br \/>Ce sont des roches form\u00e9es par des \u00e9l\u00e9ments de diff\u00e9rentes tailles projet\u00e9s par des explosions li\u00e9es \u00e0 un volcanisme phr\u00e9ato magmatique.<br \/>On note en particulier des blocs calcaires de taille d\u00e9cim\u00e9trique qui ont \u00e9t\u00e9 arrach\u00e9s \u00e0 la paroi de la chemin\u00e9e volcanique.<br \/>Des \u00e9l\u00e9ments sph\u00e9riques en couches concentriques correspondent \u00e0 des blocs de laves alt\u00e9r\u00e9s.<br \/>La matrice est fom\u00e9e d&rsquo;\u00e9l\u00e9ments fins, sableux de cendres volcaniques. Il faut imaginer des \u00e9ruptions volcaniques il y a 8 millions d&rsquo;ann\u00e9es, au mioc\u00e8ne.<\/p>\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-dc4a34b elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"dc4a34b\" data-element_type=\"section\" data-e-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-50 elementor-top-column elementor-element elementor-element-cd51654\" data-id=\"cd51654\" data-element_type=\"column\" data-e-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-361f97d elementor-widget elementor-widget-image\" data-id=\"361f97d\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/ARey_20230211_112422rl.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">bloc vers le point 7 photographie Andr\u00e9 REY<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-baaa3e7\" data-id=\"baaa3e7\" data-element_type=\"column\" data-e-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-f5c42d3 elementor-widget elementor-widget-text-editor\" data-id=\"f5c42d3\" data-element_type=\"widget\" data-e-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\t\t<p>Nous avons effectu\u00e9 \u00e0 partir de ce point une petite marche qui nous a men\u00e9 vers les anciennes exploitations de diatomites (6). Ces carri\u00e8res sont maintenant envahies par la v\u00e9g\u00e9tation. Mais la trace des exploitations reste bien visible avec des creux allant bien en contrebas de l&rsquo;ancien chemin, ceci sous les falaises de basalte du \u00ab\u00a0Ranc rouge\u00a0\u00bb.<\/p><p>Les diatomites de ces carri\u00e8res sont plutot des argiles grises riches en diatom\u00e9es. La loupe ne permet de voir que des points brillants dans une matrice grise. Il suffit de gratter ces marnes au dessus d&rsquo;une goutte d&rsquo;eau sur une lame et de\u00a0 recouvrir d&rsquo;une lamelle pour observer au microscope. Mais il est possible de laver aussi ces roches pour faire des pr\u00e9parations propres.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<section class=\"elementor-section elementor-inner-section elementor-element elementor-element-411dc93 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"411dc93\" data-element_type=\"section\" data-e-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-50 elementor-inner-column elementor-element elementor-element-7ac8b96\" data-id=\"7ac8b96\" data-element_type=\"column\" data-e-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-e540de6 elementor-widget elementor-widget-image\" data-id=\"e540de6\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"http:\/\/51.38.237.32\/l3geo\/site1\/wp-content\/uploads\/2023\/02\/Diatomites7.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\"><i>Cyclotella sp. <\/i>photographie Daniel NARDIN<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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<div class=\"elementor-column elementor-col-50 elementor-inner-column elementor-element elementor-element-5db99cc\" data-id=\"5db99cc\" data-element_type=\"column\" data-e-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-1412fa3 elementor-widget elementor-widget-text-editor\" data-id=\"1412fa3\" data-element_type=\"widget\" data-e-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\t\t<span style=\"color: #000000;\">Voici\u00a0 une image au microscope d&rsquo;une des diatom\u00e9es du genre <em>Cyclotella<\/em> qui constituent en grande partie les roches de la carri\u00e8re du Combier. Il s&rsquo;agit d&rsquo;une esp\u00e8ce \u00ab\u00a0centrique\u00a0\u00bb dont le squelette a une sym\u00e9trie radiale. Ce squelette appel\u00e9 frustule, est fom\u00e9 de 2 valves s&#8217;emboitant, comme une boite de camenbert avec le contenu cellulaire \u00e0 l&rsquo;int\u00e9rieur.<\/span>\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\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-7873ec5 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7873ec5\" data-element_type=\"section\" data-e-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-3860b5f\" data-id=\"3860b5f\" data-element_type=\"column\" data-e-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-5600034 elementor-widget elementor-widget-text-editor\" data-id=\"5600034\" data-element_type=\"widget\" data-e-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\t\t<p>Entre les \u00e9ruptions, des lacs de crat\u00e8res ont permis la vie de ces algues microscopiques et la s\u00e9dimentation de leur squelette.<\/p><p>L&rsquo;exploitation industrielle de ces diatomites a commenc\u00e9 en 1910. L&rsquo;entreprise Boutillon fabriquait des briques r\u00e9fractaires. En 1928, un cable a\u00e9rien transporteur a \u00e9t\u00e9 construit pour relier les carri\u00e8res \u00e0 l&rsquo;usine situ\u00e9e dans la vall\u00e9e \u00e0 Alyssas. L&rsquo;exploitation s&rsquo;est arr\u00e8t\u00e9e dans les ann\u00e9es 1980, mais l&rsquo;usine de briques r\u00e9fractaire d&rsquo;Alyssas, situ\u00e9e juste derri\u00e8re l&rsquo;hyperU actuel,\u00a0 a continu\u00e9 de fonctionner jusqu&rsquo;en 2009 avec de la perlite import\u00e9e de Gr\u00e8ce.<\/p>\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-a702194 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"a702194\" data-element_type=\"section\" data-e-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-50 elementor-top-column elementor-element elementor-element-b93c59c\" data-id=\"b93c59c\" data-element_type=\"column\" data-e-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-17859a1 elementor-widget elementor-widget-text-editor\" data-id=\"17859a1\" data-element_type=\"widget\" data-e-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\t\t<p>En 7, d&rsquo;autres carri\u00e8res montrent la m\u00e8me argile \u00e0 diatom\u00e9es \u00e0 l&rsquo;affleurement. \u00a0<br \/>Le long du chemin, de gros blocs de basalte prism\u00e9s \u00e9boul\u00e9s de la taille d&rsquo;une maison parfois sont visibles. <br \/>Au retour, le bord de route (8) montre une coul\u00e9e de Basalte<br \/>La synth\u00e8se des observations apparait sur cette coupe tr\u00e8s\u00a0 sch\u00e9matique<\/p><p>On peut retenir de cette visite le caract\u00e8re non durable de toute exploitation mini\u00e8re: ici le gisement a \u00e9t\u00e9 exploit\u00e9 en un demi si\u00e8cle&#8230;<br \/>Le gisement de diatomite plus riche de Saint Bauzille, d\u00e9couvert en 1950, sera compl\u00e8tement ras\u00e9 dans quelques dizaines d&rsquo;ann\u00e9es&#8230;<\/p>\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<div class=\"elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-ecdb82b\" data-id=\"ecdb82b\" data-element_type=\"column\" data-e-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-4fb4355 elementor-widget elementor-widget-image\" data-id=\"4fb4355\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" src=\"http:\/\/www.monamiph.eu\/SGA\/orig\/CR\/SGA13-05-18\/CoupeCombier.jpg\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\"><i>Coupe Sch\u00e9matique auteur Daniel NARDIN<\/i><\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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-c88f3f2 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"c88f3f2\" data-element_type=\"section\" data-e-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-c4716b0\" data-id=\"c4716b0\" data-element_type=\"column\" data-e-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-57b8b00 elementor-widget elementor-widget-text-editor\" data-id=\"57b8b00\" data-element_type=\"widget\" data-e-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\t\t<p>Les anciens clich\u00e9s IGN\u00a0 permettent de juger de l&rsquo;extension des carri\u00e8res en 1959, avant le retour de la v\u00e9g\u00e9tation. Par ailleurs, le trac\u00e9 de la route a \u00e9t\u00e9 d\u00e9plac\u00e9 depuis.<\/p>\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-f824aad elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f824aad\" data-element_type=\"section\" data-e-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-9b1f896\" data-id=\"9b1f896\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\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-0b1e99a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"0b1e99a\" data-element_type=\"section\" data-e-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-ef75028\" data-id=\"ef75028\" data-element_type=\"column\" data-e-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-bd26f66 elementor-widget elementor-widget-image\" data-id=\"bd26f66\" data-element_type=\"widget\" data-e-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<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.societegeolardeche.com\/DocsSGA\/CR\/23Combier\/Combier1959-08-26r.JPG\">\n\t\t\t\t\t\t\t<img decoding=\"async\" src=\"http:\/\/ujakbls.cluster031.hosting.ovh.net\/DocsSGA\/CR\/23Combier\/Combier1959-08-26r.JPG\" title=\"\" alt=\"\" loading=\"lazy\" \/>\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">couple st\u00e9r\u00e9oscopique du hameau de Combier aux rochers de Rancs rouge, r\u00e9alis\u00e9 par Daniel NARDIN \u00e0 partir de recadrages de clich\u00e9s IGN<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\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-90d16be elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"90d16be\" data-element_type=\"section\" data-e-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-42d34a3\" data-id=\"42d34a3\" data-element_type=\"column\" data-e-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-25616ba elementor-widget elementor-widget-text-editor\" data-id=\"25616ba\" data-element_type=\"widget\" data-e-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\t\t<strong><span style=\"text-decoration: underline;\"><span style=\"color: #000000; text-decoration: underline;\">Bibliographie :<\/span><\/span><\/strong>\n<ul>\n \t<li><span style=\"color: #000000;\">carte g\u00e9ologique de la France au 1\/50000e, feuille de Privas<\/span><\/li>\n \t<li><span style=\"color: #000000;\">\u00ab\u00a0De la diatomite d&rsquo;Alyssas &#8230; aux briques isolantes\u00a0\u00bb Yves Carles et Marie-Jo Volle, N\u00b0134, sp\u00e9cial Alyssas de MATP, pages 57-60 <\/span><\/li>\n \t<li><span style=\"color: #000000;\">site <a href=\"https:\/\/remonterletemps.ign.fr\/\">https:\/\/remonterletemps.ign.fr\/<\/a> clich\u00e9s de la mission 1959-08-26<\/span><\/li>\n<\/ul>\n<div style=\"text-align: right;\"><strong><em><span style=\"color: #000000;\">Daniel NARDIN<\/span><\/em><\/strong><\/div>\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<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Diatomites de Combier, 21 janvier 2023, SGA Cette premi\u00e8re sortie SGA de l&rsquo;ann\u00e9e a b\u00e9n\u00e9fici\u00e9 de bonnes \u00e9claircies ensoleill\u00e9es, malgr\u00e9 un froid vif. Il y a eu 7 participants en plus de\u00a0 Daniel NARDIN qui guidait. Un premier arr\u00eat \u00e0 cot\u00e9 du RDV dans la zone commerciale a permis de voir les alternances en bancs &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/www.societegeolardeche.com\/index.php\/diatomites-de-combier\/\"> <span class=\"screen-reader-text\">Diatomites de Combier<\/span> Lire la suite\u00a0\u00bb<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"no-sidebar","site-content-layout":"page-builder","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"class_list":["post-228","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/pages\/228","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/comments?post=228"}],"version-history":[{"count":37,"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/pages\/228\/revisions"}],"predecessor-version":[{"id":1881,"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/pages\/228\/revisions\/1881"}],"wp:attachment":[{"href":"https:\/\/www.societegeolardeche.com\/index.php\/wp-json\/wp\/v2\/media?parent=228"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}