The Cambrian-Ordovician boundary in the Cordillera Oriental, NW Argentina

ALBANESI G.L; GIULIANO, M.E.; PACHECO, F.; ALBANESI, G.L., MONALDI, C.R., ORTEGA, G. & TROTTER, L.A.; MONALDI C.R.

Harrisonburg

Simposio; 12th International Symposium on the Ordovician System; 2015

IUGS UNESCO

The global Cambrian/Ordovician inter-systemic boundary was a controversial problem regarding thefossil record and reference stratigraphic section. The Cambrian/Ordovician Boundary Working Group ofthe International Subcommission on Ordovician Stratigraphy (ICS-IUGS) selected the conodont speciesIapetognathus fluctivagus as the index fossil for establishing the boundary after comprehensivetaxonomic studies. Nicoll et al. (1999) monographed I. fluctivagus and other species of Iapetognathus aswell as its purported ancestor Iapetonudus ibexensis, and they documented their known occurrences,ranges and correlations with other fossils considered significant to define the base of the Tremadocian.Cooper et al. (2001) proposed the section of Green Point, western Newfoundland, Canada, for the GSSPfor the Cambrian/Ordovician (C/O) boundary determined there by the first appearance of I. fluctivagus,which was later approved by the IUGS executive.