Final Review of ChronometricAge Extension to Darwin Core

TDWG Standards

The ChronometricAge Task Group ( has completed a round of public commentary for the Chronometric Age vocabulary extension to Darwin Core. During the course of the review, several amendments, clarifications and additions were recommended and implemented. The discussions and changes are documented (Github issues 15-24 at and the results have been deployed to both the normative term list for the vocabulary ( and its Quick Reference Guide ( The latter is the easiest way to assess the current state of the vocabulary, while the former provides the full history of the terms with all of their metadata.

The Task Group welcomes any further feedback now that these changes are in place. The continuation of the original 30-day period for public comment (beginning 2020-11-21) has been extended to 5 March 2021 to allow stakeholders to assess the updated Chronometric Age Extension and provide further recommendations if necessary. The purpose of the review is to allow the broadest possible community to see the proposed vocabulary in action and to assess whether it is sufficiently complete and clearly documented that it can provide a stable addition to the standards for sharing biodiversity data.

For this extended public commentary period, no update was made to the GBIF Chronometric Age Extension document. An update will be provided when the vocabulary has been ratified.

To view the proposal and/or engage in the review, visit, which will provide further guidance and the means to comment. If you are unable or prefer not to submit comments via GitHub, you can send comments to the ChronometricAge Task Group convenor at In the absence of objections or substantive amendment requests, the review will close on 2021-03-05.