@prefix qx8: <http://data.loterre.fr/ark:/67375/QX8> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .

qx8: a skos:ConceptScheme .
qx8:-FCFL5N44-P
  skos:definition "Le Ludfordien est le septième étage du Silurien, dans l'ère paléozoïque. Cette subdivision est la plus récente de la série géologique du Ludlow et s'étend de -425,6 ± 0,9 à -423,3 ± 2,3 millions d'années. Cet étage est précédé par le Gorstien et suivi par le Pridoli. Au-dessus du point stratotypique mondial (PSM) se trouve la base de la zone à graptolite Saetograptus leintwardinensis. (Adapté de : <a href=\"https://fr.wikipedia.org/wiki/Ludfordien\">https://fr.wikipedia.org/wiki/Ludfordien</a>)"@fr, "In the geologic timescale, the Ludfordian is the upper of two chronostratigraphic stages within the Ludlow Series. Its age is the late Silurian Period, and within both the Palaeozoic Era and Phanerozoic Eon. The rocks assigned to the Ludfordian date to between 425.6 ± 0.9 Ma and 423.0 ± 2.3 Ma (million years ago). The Ludfordian Stage succeeds the Gorstian Stage and precedes the Pridoli Epoch. It is named for the village of Ludford in Shropshire, England. The Lau event is a rapid pulse of cooling during the Ludfordian, about 424 million years ago; it is identified by a pulse of extinctions and oceanic changes. It is one of the series of fast sea-level and excursions in oxygen isotope ratios that signal fast switches between warm and cold climate states, characteristic of the Silurian climatic instability. The Lau Event occurred during an extended period of elevated seawater saturation state, explained by reservoirs of the planet's fresh water being locked up in massive polar ice caps. The sudden reappearance in normally saline marine environments of stromatolites and a mass occurrence of oncoids during the event suggested that minor extinction events like the Lau Event also resulted in periods of reduced grazing pressures on surviving \"disaster biota\", which can be compared to the aftermath of the more catastrophic end-Ordovician and end-Permian mass extinctions. (Adapted from: <a href=\"https://en.wikipedia.org/wiki/Ludfordian\">https://en.wikipedia.org/wiki/Ludfordian</a>)"@en ;
  a skos:Concept ;
  skos:inScheme qx8: ;
  skos:broader qx8:-378SLFS7-C ;
  skos:prefLabel "Ludfordian"@en, "Ludfordien"@fr ;
  skos:exactMatch <https://fr.wikipedia.org/wiki/Ludfordien>, <https://en.wikipedia.org/wiki/Ludfordian> .

qx8:-378SLFS7-C
  skos:prefLabel "Ludlow"@en, "Ludlow"@fr ;
  a skos:Concept ;
  skos:narrower qx8:-FCFL5N44-P .