. The Norian was named after the
Noric Alps in
Austria. The stage was introduced into scientific literature by Austrian geologist
Edmund Mojsisovics von Mojsvar in 1869. The Norian Stage begins at the base of the
ammonite biozones of
Klamathites macrolobatus and
Stikinoceras kerri, and at the base of the
conodont biozones of
Metapolygnathus communisti and
Metapolygnathus primitius. A global reference profile for the base (a
GSSP) had in 2009 not yet been appointed. The top of the Norian (the base of the Rhaetian) is at the first appearance of ammonite species
Cochloceras amoenum. The base of the Rheatian is also close to the first appearance of conodont species
Misikella spp. and
Epigondolella mosheri and the
radiolarid species
Proparvicingula moniliformis. In the
Tethys domain, the Norian Stage contains six ammonite biozones: • zone of
Halorites macer • zone of
Himavatites hogarti • zone of
Cyrtopleurites bicrenatus • zone of
Juvavites magnus • zone of
Malayites paulckei • zone of
Guembelites jandianus Subages The Norian is divided into three global subages or substages: •
Lacian (lower Norian) •
Alaunian (middle Norian) •
Sevatian (upper Norian) Many older studies considered the Rhaetian to be the uppermost substage of the Norian, though it has subsequently been raised to its own stage. The
Revueltian land-vertebrate faunachron (LVF) corresponds to part of the Norian (215–207 Ma), and it is probable that the
Otischalkian and
Adamanian LVFs (227–215 Ma) are also early-middle Norian in age. == Notable formations ==