Graphic correlation of Argentine Precordillera and North American Lower/Middle Ordovician sections

• 来源期刊: 幕-国际地学杂志（英文版）
• 年，卷（期）: 2006,（1）
• 页码范围: 16-19
• 页数: 4页
• 语种: 英文

摘要

Present work demonstrates that a level equivalent to the proposed Whiterockian basal GSSP can be located graphically in a composite section anchored by the Niquivil section of the Argentine Precordillera. The FAD of Cooperignathus aranda in the Niquivil composite section, a candidate for GSSP of the Lower/Middle Ordovician boundary, projects to a level very close to the FAD of Tripodus laevis in the Whiterockian reference section. The conodont-based framework reported here includes the potential for recognition of the proposed Whiterock Canyon-based GSSP, the Cooperignathus aranda-based GSSP, and, possibly, the Baltoniodus triangularisbased GSSP, recently proposed.