ICS Supermodel

WARNING

This page and all the information about the ICS Supermodel is in an early phase of development.

This work was formally unveiled at the STRATI 2026 conference in July 2026.

Last updated: 2026-07-01 by Nicholas Car

  1. Abstract
  2. Motivation
  3. Modelling System
  4. Integrative Model
  5. Foreground Models
    1. GTS Model
    2. Stratigraphy Model
    3. Visual Chart Model
    4. GSSP Model
  6. Background Models
    1. RDF
    2. OWL
    3. OWL
    4. THORS
    5. GeoSPARQL
    6. schema.org
    7. SKOS
  7. Datasets
    1. Geological Timescale Dataset
    2. Visual Chart Dataset
    3. GSSP Dataset
  8. References

1. Abstract

The ICS Stratigraphy ‘Supermodel’ is an information model covering many aspects of the stratigraphy domain as characterised by the International Commission on Stratigraphy (ICS).

It is made to allow for the growth of formal data definitions within the stratigraphy domain with the side benefits of allowing for the integration of data both across distinct aspects of the domain and also for data outside the domain, such as broader geological data, to be joined with it.

2. Motivation

Geology and resource sector science and engineering have long used large volumes of sophisticated data however many projects have to re-implement data associations related to stratigraphy due to a lack of standardised models and datasets in that subdomain.

The International Commission on Stratigraphy (ICS), as the international authority responsible for establishing the fundamental scale used to represent the history of the Earth, has long published the Chronostratigraphic Chart as the principal reference resource within the field. Since 2026, this Chart has been made available as data, rather than solely as a document. The ICS is now undertaking efforts to define additional stratigraphic domain elements through the suite of standardised resources encompassed by this Supermodel, to enable projects to maximise reuse of stratigraphic information and to minimise redundant reimplementation.

By improving the consistency and authority of stratigraphy domain data, automated agents that on-deliver and otherwise reuse ICS data, such as AI and web search systems, will have a greater likelyhood of doing so faithfully.

3. Modelling System

3.1. Semantic Web

The Semantic Web as a technical methodology and specific set of data models used widely for machine-readable content often, but not always, available on the Internet. Semantic Web approaches are used for this Supermodel to ensure its elements both reuse existing resources in this sector, such as international geological models, and so that they can be maximally reused by others. Semantic Web resources are generally considered to exhibit interoperable and open data best practices.

Specific reasons for the use of Semantic Web for this Supermodel are:

  1. Semantic Web models can reuse other model’s elements to a degree other modelling systems can’t
    • this allows for maximal interoperability through shared model elements and modelling patterns
  2. A large body of Semantic Web models in relevant domains already exist that can be reused
  3. Semantic Web models are “AI ready”
    • they present their data and definitions in ways that Large Language Models and other technologies can readily use

The two fundamental models within the Semantic Web that are used here are:

  1. RDF - Resource Description Framework
    • a technical, structural model for associating data elements
  2. OWL - Web Ontology Language
    • a set theory-based modelling language that represents conceptual classes of things and their properties

RDF provides the data structure and OWL the general-purpose information model which these Supermodel models use to represent things such as stratigraphic unit types, time periods, GSSP locations and so on.

3.2. The Supermodel

As with all things within this Supermodel’s remit, the Supermodel itself has a formal OWL model. Its description says it is “…an enterprise data model that provides a structure for the creation of models for specialised datasets that allow for their uniqueness to be preserved but also provide for their deep integration.”

The main elements of the Supermodel that matter in this case are the Foreground and Background models:

Several specialised Foreground Models are already defined for obvious aspects of the stratigraphy domain and a number of pre-existing Background models covering generic domains relevant to stratigraphy such as spatiality, temporality, conceptual relations and scientific referencing, have been selected for Foreground Model alignment.

More Foreground and Background models are expected as scope grows.

3.3. Modelling Patterns

3.3.1 Introducing Patterns

A modelling pattern is a reusable approach for modelling a recurring information scenario. For example, the Time Ontology in OWL provides a pattern for the expression of instances in time and periods of time that the various foreground models use when they wish to represent time objects.

A more fundamental pattern is the qualified relation which is a basic graph data model pattern used to link one object to another with qualifying information, such as the beginning of an Age in the chronostratigraphic chart being liked to a time representation of it in millions of years ago (MYA) qualified with an uncertainty. An example:

3.3.2 List of Patterns

It is not possible to make a comprehensive listing of patterns used by models as they overlap, however here are some significant ones used in this Supermodel:

Pattern Purpose Defined By Used In
Universal object identifiers To ensure all data objects, both definitional and class instances, are identified uniquely and universally RDF Model all
Feature/Geometry Linking To associate an object with a geospatial location on Earth GeoSPARQL Stratigraphy Model, GSSP Model
Indicating Temporality To associate an object with a temporal location Time Ontology in OWL GTS Model
Literature referencing by ID To provide certainty in referencing scientific literature schema.org GSSP Model
more coming…      

4. Integrative Model

This Supermodel’s integrative model is a skeleton model that joins the various foreground models together via relations between classes and them in other models.

Here the Stratigraphic Model is joined to the Geological Timescale model by means of instances of the former’s Stratigraphic Unit class indicating related instances of the latter’s Geocronological Era by the predicate has age.

This model is created entirely from elements within the Foreground and Background Models but is presented as a stand-alone model also, to be used as a Supermodel high-level view.

5. Foreground Models

The Foreground Models in this Supermodel are the main, specialised, domain models developed specifically for this situation.

5.1. Geologic Timescale (GTS) Model

http://resource.geosciml.org/ontology/gts

This model was originally developed in 2011 by Cox & Richards in 2012 ref as a sophisticated Time Ontology in OWL ref-based timescale dataset.

This model contains specialised forms of a Geocronologic Era class to represent the various Chronostratigraphic Chart time objects, such as Period, Age, Super-Eon and so on. It also has a specialised time instant class called Geocrhonologic Boundary used to contain the starting and finishing details of Geocronologic Era instances.

It also contains a Stratigraphic Point class which is used to associate Geocrhonologic Boundary objects with some GSSP information.

5.2. Stratigraphy Model

http://resource.geosciml.org/ontology/stratigraphy

This model is developing alongside this Supermodel and will be published soon - mid-2026.

It contains detailed stratigraphic domain information.

5.3. ICS Visual Chart Model

http://resource.geosciml.org/ontology/isc-visual-chart

This is a SKOS vocabulary representation of the instances of Geocronologic Era class instances - the Chronostratigraphic Chart’s elements - with some time information taken from the Geologic Timescale Model and additions such as colours created to allow for the generation of the Chronostratigraphic Chart in traditional visual form from data, as it is displayed at https://stratigraphy.org/chart.

When generated from parts, this model contains multilingual and alternate chronometric and stratigraphic labels as well.

5.4. GSSP Model

http://resource.geosciml.org/ontology/gssp

This model is developing alongside this Supermodel and will be published soon - mid-2026.

It contains a Semantic Web representation of the Global Boundary Stratotype Section and Points (GSSP) information online at https://stratigraphy.org/gssps and will eventually be used to generate that web page, just as the Visual ICS Chart Model already generates the online Chart at https://stratigraphy.org/chart.

Other Foreground Models

More coming…

6. Background Models

6.1. RDF Model

https://www.w3.org/TR/rdf12-concepts/

The Semantic Web’s fundamental data structure model. ref

The model defines the low-level data structure used by all other models within the Supermodel and data created according to those models.

6.2. OWL Model

https://www.w3.org/TR/owl2-overview/

A data modelling, model built on RDF and widely used within the Semantic Web. ref

OWL provides us with mathematical set theory-based mechanisms for modelling classes of objects.

6.3. Time Ontology in OWL

https://www.w3.org/TR/owl-time/

A fundamental domain ontology of temporal concepts, for describing the temporal properties of resources. ref

This ontology provides us with the basic temporal objects we need for geological time periods and for the expression of relationsips between them, such as Jurrasic being before Cretaceous.

6.4. Temporal Hierarchical Ordinal Reference System (THORS) Model

http://resource.geosciml.org/ontology/timescale/thors

This model, created in 2005 ref, provides a Semantic Web representation of the Temporal Hierarchical Ordinal Reference Systems defined in GeoSciML ref using mostly Time Ontology in OWL ref and SKOS elements.

6.5. GeoSPARQL

http://www.opengis.net/doc/IS/geosparql/1.1

GeoSPARQL contains a small spatial domain OWL ontology that allow literal representations of geometries to be associated with spatial features and for features to be associated with other features using spatial relations.

GeoSPARQL Feature instances are used in this Supermodel to represent both GSSP locations and stratigraphic units that GSSPs are indicated within.

6.6. schema.org Model

https://schema.org

“Schema.org is a collaborative, community activity with a mission to create, maintain, and promote schemas for structured data on the Internet” - https://schema.org.

schema.org provide a large number of general-purpose classes and predicates use to represent non-specialist information objects and relations, such as names (schema:name) and descriptions for things.

6.7. Simple Knowledge Organization System (SKOS) Model

https://www.w3.org/TR/skos-reference/

A common data model for sharing and linking knowledge organization systems via the Web ref

SKOS is widely used for modelling vocabularies of concepts.

7. Datasets

This section contains datasets that have been created according to the models in the previous section.

7.1 Geological Timescale Dataset

http://resource.geosciml.org/vocabulary/timescale/gts2020

An RDF/OWL representation of the GeoSciML Geologic Timescale according to the Geologic Timescale Model.

Data online at https://github.com/i-c-stratigraphy/chart/blob/main/supermodel/datasets/gts2020.ttl.

7.2 ICS Visual Chart Dataset

https://stratigraphy.org/chart

A representation of the ICS’ Chronostratigraphic Chart in RDF/OWL according to the SKOS vocabulary model.

Data online at https://github.com/i-c-stratigraphy/chart/blob/main/chart.ttl

7.3 GSSPs Dataset

TODO

8. References

  1. World Wide Web Consortium, RDF 1.2 Concepts and Abstract Data Model. W3C Candidate Recommendation (2026). https://www.w3.org/TR/rdf12-concepts/
  2. World Wide Web Consortium, OWL 2 Web Ontology Language Document Overview (Second Edition). W3C Recommendation (2012). https://www.w3.org/TR/owl2-overview/
  3. Cox, S.J.D.,Richard, S.M. A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards. Geosphere, 1, 119-137 (2005). https://doi.org/10.1130/GES00022.1
  4. Cox, S.J.D., Richard, S.M. A geologic timescale ontology and service. Earth Sci Inform 8, 5–19 (2015). https://doi.org/10.1007/s12145-014-0170-6
  5. Open Geospatial Consortium, OGC Geoscience Markup Language 4.1 (GeoSciML). OGC Implementation Standard (2017). http://www.opengis.net/doc/geosciml/4.1
  6. World Wide Web Consortium, SKOS Simple Knowledge Organization System Reference. W3C Recommendation (2009). https://www.w3.org/TR/skos-reference/
  7. World Wide Web Consortium, Time Ontology in OWL. W3C Recommendation (2022). https://www.w3.org/TR/owl-time/