Earliest and Latest Chronostratigraphy - Darwin Core Hour Input Form 2/19/2019 15:32:26

[iDigBioBot]

A user submitted this information via the Darwin Core Hour webform:
Timestamp: 2/19/2019 15:32:26
Please provide a topic of interest: Are people reporting earliest and latest chronostratigraphy? If they are, when the earliest and latest are the same do they just report the same information twice? Are people following the GSA or International Chrono charts ( i.e. Early, Middle, Late as opposed to Lower, Middle, Upper)? Also, how are people dealing with informal things like middle Pliocene?
Are you capable of and interested in participating: No
Who else would you recommend to participate in the presentation:
What resources can you point to:
Your name: Leslie Skibinski
Your email: lls94@cornell.edu
Your GitHub username:

[debpaul]

Dear @tdwg/paleo @tdwg/dwc-qa many of you may have input for Leslie. She does not have a gitHub account, so we will need to use email to loop her into the responses. This is another example of why we need a resource that makes it easy for our stakeholders to see distinct values for a given term (like context) in a given realm (in this case, paleo).

[ekrimmel]

Hi Leslie,

For our invertebrate paleontology collection at the LA County Museum, we report earliest and latest chronostratigraphy, and just duplicate the value when it isn't actually a range. We follow GSA, but either would be correct and my suggestion is to use whichever you prefer--making data users or data aggregators synonymize between standards seems fine to me. For an example where the modifier is not part of the formal name, e.g. your "middle Pliocene," we record the modifier in a separate field in our database but do not send it out to aggregators at this time...

[Jegelewicz]

Are people reporting earliest and latest chronostratigraphy? If they are, when the earliest and latest are the same do they just report the same information twice?

For collections in Arctos, the answer is "it depends". Geology attributes are added to locality and you can add as many as you like, so some may be adding multiple to indicate earliest and latest, while others may only add one, but I don't think anyone is adding two of the same and so our chronostratigraphy attributes may not be living up to expectations of the community for including and "earliest" and "latest".

Are people following the GSA or International Chrono charts ( i.e. Early, Middle, Late as opposed to Lower, Middle, Upper)?

She can view our geology vocabulary: http://arctos.database.museum/info/ctDocumentation.cfm?table=CTGEOLOGY_ATTRIBUTE
Scrolling required, because this table includes both lithostratigraphy and chronostratigraphy. It looks like our current group of paleo collections are adhering to the "Upper, Middle, Lower", but we could easily add the "Early, Middle, Late" and collections could choose.

Also, how are people dealing with informal things like middle Pliocene?

Probably in the remarks of the assigned geology attribute.

To see how the geology attributes work in Arctos, take a look at the locality for this specimen (scroll to the bottom of the locality section): http://arctos.database.museum/guid/UTEP:ES:1-1002

[Nicole-Ridgwell-NMMNHS]

Upper, Middle, and Lower are often used interchangeably with Early, Middle, and Late, however there is a formal difference - the former are chronostratigraphic terms denoting a relative position in layers of rock whereas the latter are geochronologic terms denoting periods of time. The reason there is a difference between GSA and the international chart you're looking at is that the GSA chart is a geochronologic chart and the international chart is chronostratigraphic.

Basically, geochronology is about absolute dating of rocks and chronostratigraphy is about relative dating of rocks. They're both very intertwined, and it is often a fine distinction between the two. Here is a publication from GSA that provides more clarification: http://www.geosociety.org/gsatoday/archive/23/3/article/i1052-5173-23-3-4.htm

For paleo collections it can be accurate to use either - the dating of a site could be be based on both relative stratigraphy or absolute dating, however most often it is probably just relative stratigraphy.