Class:GeologicalContext

[mtrekels]

Parent	ObjectGroup
Label	Geological Context
Definition	Geological information, such as stratigraphy, that qualifies a region or place.
Usage
Required	No
Repeatable	Yes
Relationships	Range: ObjectGroup | Class-level properties: Reference, Identifier, MeasurementOrFact
Potential standards/vocabularies/ontologies to adopt	http://rs.tdwg.org/dwc/terms/GeologicalContext
Notes

[falkogloeckler]

These might need to be discussed with the TDWG ESP IG (https://github.com/tdwg/esp)

[Jegelewicz]

I am neither a geologist nor a biologist, but as I have been working to import several large collections of fossil material to Arctos, "geology" has become part of my most recent learning experience. Forgive me if I say anything blatantly dumb as I am an outsider looking in here.

My very first gut reaction to this class is - are we really discussing time or are we discussing strata? Some of the terms here can be related to geologic time frames in a very direct manner, but others perhaps not so much. From what I have learned, all of the Lithostratigraphic terms can cross variable periods of geologic time depending upon where they were deposited. In Arctos, we have determined that these terms cannot be readily placed into a hiearchy nor given distinct begin and end date ranges on a global basis. Perhaps these do not belong in a category that includes "TimeRange":

bed formation group member

[Jegelewicz]

Somewhat similarly, biostrata may have variable dates depending on their "where". So maybe these terms belong elsewhere too?

highestBiostratigraphicZone lowestBiostratigraphicZone

[mswoodburn]

Good point - this class originally focused on chronostrat, but then adopted a lot of the terms from dwc:GeologicalContext, so the name doesn't make sense now. We should perhaps adopt the same name as the DwC class (and basically adopt the DwC class wholesale?)

[Jegelewicz]

Even the International Commission on Stratigraphy (ICS) notes in its definitions that:

Stratigraphic units based on one property will not necessarily coincide with those based on another.

It seems to me that if what we are attempting here is to get a geologic time frame for the collection we should instead have a class named Geochronometry.

A branch of geochronology that deals with the quantitative (numerical)measurement of geologic time. The abbreviations ka for thousand (103), Ma for million (106), and Ga for billion (milliard of thousand million, 109) years are used.

Everything else are StratigraphicClassification

The systematic organization of the Earth's rock bodies, as they are found in their original relationships, into units based on any of the properties or attributes that may be useful in stratigraphic work.

One thing we have decided within Arctos is that we need the classes of stratigraphy just as they are listed by ICS:

Chronostratigraphy (we intend to stick to the International Commission on Stratigraphy Table of Geologic Time) Lithostratigraphy Biostratigraphy Magnetostratigraphy (we haven't had use for this yet, but I assume it will happen eventually)

and that there are (or eventually will be) other needs here as well:

Petrology Biochronology Mineralogy

And any location might have attributes of all of the above - they seem far too specific for most "collections" and more applicable to individual occurrence locations or objects

[Jegelewicz]

We should perhaps adopt the same name as the DwC class (and basically adopt the DwC class wholesale?)

Maybe? I'd need to go review all of that - but see above, I'm not sure we NEED all of that in COLLECTION description. Honestly, there are probably very few collections from a single lithostratum and listing them all for any given collection doesn't seem very effective either.

[Jegelewicz]

If we stick with the class GeologicTimeRange, then I suggest we only include terms that actually can be associated with a time range so:

earliestAgeOrLowestStage earliestEonOrLowestEonothem earliestEpochOrLowestSeries earliestEraOrLowestErathem earliestPeriodOrLowestSystem latestAgeOrHighestStage latestEonOrHighestEonothem latestEpochOrHighestSeries latestEraOrHighestErathem latestPeriodOrHighestSystem

but add the biochronologic terms too:

earliestLandMammalAge earliestLandVertebrateAge latestLandMammalAge latestLandVertebrateAge

and most importantly the Geochronometry:

earliestGeologicDate latestGeologicDate

As each of the terms should include a date or associated date range, they would represent the GeologicTimeRange:

Period of geologic time within which the collection objects were deposited.

[Jegelewicz]

Suggested definition

Period of geologic time within which the collection objects were deposited.

[l-tilley]

https://en.wikipedia.org/wiki/Geochronology

[ekrimmel]

I agree with your comments above, @Jegelewicz.

Also, I was talking to @ljwalker the other day about ideas for how to recommend a controlled vocabulary for the geologic time fields encompassed in this class. Paraphrasing her response here: The ICS chart provides lots of detail, but both the ICS and Geological Society of America time scales change every year. The changes are not dramatic and are mostly refinements to the numerical ages, not the relative age names and their hierarchy. However, a more static resource would be that of Gradstein et al. 2012. This was the last official publication of the geologic time scale and would provide consistency for recommending controlled vocabulary values. The publication itself is a massive tome, so attached is the one page most likely of interest here: Geologic_Time_Scale_2012_Pg24.pdf

[Jegelewicz]

@ekrimmel EVERYTHING changes and we should figure out ways to adapt. If our vocabulary is tied to ICS, then perhaps these terms also require a determination date (to which ICS are you referring?). Being tied to a static (and so probably outdated) set of values would not be approved by Dusty :-) and frankly, I don't like it either.

It's no different than taxonomy - we need to figure out how to live with moving targets.

[debpaul]

Discussion at CD TG BBQ 30 April.

1. May need to split into more than one class
2. @ramonawalls to contact Laura Brenskelle's (she's @lbrensk on github) group on this AND Holly Little's ESP group to have this conversation and review together. See https://github.com/hollyel (@hollyel on github)
3. May be able to re-use some of existing dwc; may be able to use work of the existing groups mentioned in number 2.

Thanks @ramonawalls!

[mswoodburn]

As agreed in the last working session, renamed to GeologicalContext to align with Darwin Core.