0000000000170182
AUTHOR
Annie Reffay
Les formations carbonatées de Dortan (Ain) : premières observations
International audience
Les formations carbonatées du Dortan (Ain) : premières observations
Calcium carbonate, deposits have built four terraces, near Dortan, in the Southern part of Central Jura (46° lat. N). These deposits may just cover other terraces associated themselves with an ice-dammed lake. They include two types : 1) tufa deposits, porous and hard, with conspicuous tree remains ; 2) lake chalk, compact and brittle, snowing lenses and, sometimes, varves, with shells and pieces of charcoal. C 14 dating and analyses should allow to insert these deposits in the Jura Holocene chronology and to explain their situation at such a high latitude.