AN OVERVIEW OF THE NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE

Simply put, a stratigraphic code is a set of procedures to follow to create a “formal” stratigraphic unit. Examples of such codes include the North American Stratigraphic Code (the “Code”) and the International Stratigraphic Guide.

The role of the North American Commission on Stratigraphic Nomenclature (NACSN) is to ensure that the Code keeps abreast of new scientific developments, and to review and revise the Code as necessary. Such revisions can be initiated either by NACSN or by any member of the geoscience community, as outlined in Article 21 of the Code. In addition, the members of the Commission, who represent the United States, Canada, Mexico, and now South America, are also available to provide advice on stratigraphic procedures and to promote the study of stratigraphy.

NACSN is not an arbiter or a steward of stratigraphic usage. Historically, these roles have been filled by geologic names boards at various state, provincial and federal geological surveys; however, over the past two decades, many of these boards have been downsized or eliminated. The recent creation of digital lexicons, such as GEOLEX and WEBLEX, has again emphasized the critical role played by such geologic names boards.

Innovative parts of the Code that were introduced in 1983 are still underutilized, in particular, the use of lithodemic units for metamorphic and plutonic rocks. Inclusion of sequence stratigraphic nomenclature within the Code has been under consideration for many years, and is awaiting consensus from the geoscience community as to if, and how, such nomenclature should be formalized.