%0 Journal Article
%T New evidence for the Hirnantian (Upper Ordovician) in Belgium? An integrated isotopical, biostratigraphic and sedimentologic approach
%A Vanmeirhaeghe Jan
%A Yans Johan
%A Pr¨¦at Alain
%A Grassineau Nathalie
%J Carnets de G¨¦ologie
%D 2005
%I Carnets de G¨¦ologie
%X The Hirnantian is an important time in Earth history as it includes one of the major episodes of continental glaciation and marine mass extinction (e.g. Brenchley et alii, 1994). Positive C-isotope excursions and an eustatic lowering of sea level extend from a level near the base of the Normalograptus extraordinarius-N. ojsuensis Zone (lower Hirnantian) to a level within the upper Hirnantian N. persculptus Zone. C-isotope values decline to pre-glacial levels throughout the extent of uppermost Hirnantian strata. At least two discrete and distinct positive shifts of ¦Ä13Corg have been observed globally; they may coincide with two pulses of peak glaciation (Melchin et alii, 2003; see also Sutcliffe et alii, 2000).
%K Ordovician
%K Hirnantian
%K glaciation
%K chitinozoans
%K sedimentology
%K stable carbon isotopes
%K Condroz Inlier
%U http://paleopolis.rediris.es/cg/CG2005_M02/CG2005_M02_Abstract12.html