GSSP for Roadian Stage
Definition:
The base of the Guadalupian Series and Roadian Stage is defined at 42.7m above the base of the Cutoff Formation in Stratotype Canyon, Texas, U.S.A. It coincides with the first occurrence of conodont Jinogondolella nankingensis, in the transitional continuum from Mesogondolella idahoensis to Jinogondolella nankingensis.
Sedimentology:In the GSSP Section the Cutoff Formation comprises the limestone unit of the Shumard Member, the shale and limestone units of the El Centro Member and the limestone unit of the Williams Ranch Member. The GSSP is defined at 42.7m above the base of the Cutoff Formation in the limestone unit of the El Centro Member, 29cm below a prominent shale band |
Primary Markers:
The GSSP is at the first occurrence of conodont Jinogondolella nankingensis, in the transitional continuum from Mesogondolella idahoensis to Jinogondolella nankingensis.Correlation Events:
Conodont FAD Jinogondolella nankingensisBack to GSSP Table