Vocabulary

This file contains the CGI Geologic Unit Part role vocabulary, as defined by the IUGS Commission for Geoscience Information (CGI) Geoscience Terminology Working Group. This vocabulary includes terms to specify the role played by a constituent part of a geologic unit. These terms may be used to populate GeologicUnit.part.GeologicUnitPart.role, and GeologicUnit.composition.compositionPart.role. There are terms in this vocabulary that only apply to one or the other of these properties, but after an effort to create two separate vocabularies, it was decided to use a single vocabulary in order to avoid having the same concept in more than one closely related vocabulary. The duplication of applicable concepts in the two contexts (GeologicUnit.part.GeologicUnitPart.role and GeologicUnit.composition.compositionPart.role) arises because the model allows representation of complex geologic unit descriptions in more than one way. A complex geologic unit like a migmatite complex or a lithologically heterogeneous stratigraphic unit will have many different lithologic components. The simplest approach to representing the lithologic heterogeneity is to report a single GeologicUnit element with compositionParts for each lithologic component; the role on these compositionParts provides information about what kind of parts they are and perhaps something about their relationship, along with the kinds of rock they are composed of. A more complex alternative approach is to represent the various components each as GeologicUnit elements, each with compositionPart links to the rock type(s) composing that part. These component GeologicUnit elements are aggregated by GeologicUnit.part.GeologicUnitPart elements, with roles in the aggregation for each GeologicUnit part. The benefit of the more complex approach is that additional descriptive properties provided by the GeologicUnit content model can be assigned to each part, as well as GeologicRelations between the parts. The role of the compositionParts in these more 'disaggregated' GeologicUnit elements would be a simpler 'composition' kind of role, because the heterogeneous 'whole' unit would be described in GeologicUnitParts that are more lithologically homogeneous. Its a trade-off between simplicity and expressiveness.

• only part
• part of
  • facies
  • inclusion
    • blocks
    • concretion
    • enclave
    • pendants
      • rafts
      • roof pendant
      • screen
    • tectonic block
    • xenolith
  • lithosome
    • bed lithosome
    • cyclic bedding package
    • geologic unit matrix
    • irregular lithosome
    • layer lithosome
    • lenticular lithosome
    • vein or dike lithosome
  • stratigraphic part
    • marker bed
  • unspecified part role