Tournaisian

EtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the conodontSiphonodella sulcata (discovered to have biostratigraphic issues as of 2006).Lower boundary GSSPLa Serre hill, Montagne Noire, France
43°33′20″N3°21′26″E / 43.5555°N 3.3573°E / 43.5555; 3.3573Lower GSSP ratified1990Upper boundary definitionFAD of the benthic foraminiferUpper boundary GSSP, Guangxi, China
24°26′00″N109°27′00″E / 24.4333°N 109.4500°E / 24.4333; 109.4500Upper GSSP ratified2008

The Tournaisian is in the ICSgeologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from 358.86 Ma to 346.7 Ma. It is preceded by the Famennian (the uppermost stage of the Devonian) and is followed by the Viséan. In global stratigraphy, the Tournaisian contains two substages: the Hastarian (lower Tournaisian) and Ivorian (upper Tournaisian). These two substages were originally designated as European regional stages.