Review core model and scope - Geology

GeologicFeature

Class

Proposed

The abstract GeologicFeature class represents a conceptual feature that is hypothesized to exist coherently in the world.
   * this corresponds with a "legend item" from a traditional geologic map
   * while the bounding coordinates of a Geologic Feature may be described, its shape is not.
The implemented Geologic Feature instance acts as the "description package"
    * the description package is classified according to its purpose as an Instance, TypicalNorm, or DefiningNorm.

GeologicUnit

Class

Proposed

Operationally, the GeologicUnit element is a container used to associate geologic properties with some mapped occurrence (through GeologicFeature.occurrence -> MappedFeature link), or with a geologic unit ControlledConcept in a vocabulary (through the GeologicUnit.classifier ->ControlledConcept link).
Conceptually, may represent a body of material in the Earth whose complete and precise extent is inferred to exist (NADM GeologicUnit, Stratigraphic unit in sense of NACSN or Intnl Stratigraphic Code), or a classifier used to characterize parts of the Earth (e.g. lithologic map unit like 'granitic rock' or 'alluvial deposit', surficial units like 'till' or 'old alluvium').
Spatial properties are only available through association with a MappedFeature. Includes both formal units (i.e. formally adopted and named in the official lexicon) and informal units (i.e. named but not promoted to the lexicon) and unnamed units (i.e. recognisable and described and delineable in the field but not otherwise formalised).
Will be made Abstract when a complete (enough) set of specialized subtypes is defined.

GeologicStructure

Class

Proposed

A configuration of matter in the Earth based on describable inhomogeneity, pattern, or fracture in an EarthMaterial The identity of a GeologicStructure is independent of the material that is the substrate for the structure. GeologicStructures are more likely to be found in, and are more persistent in, consolidated materials than in unconsolidated materials. Properties like "clast-supported",  "matrix-supported", and "graded bed" that do not involve orientation are considered kinds of GeologicStructure because they depend on the configuration of parts of a rock body. Includes: sedimentary structures.
In GeoSciML 2.0 Fabric is treated as a class that describes an EarthMaterial (FabricDescription). The general GeologicRelation is used to associate penetrative GeologicStructures with GeologicUnits.

ShearDisplacementStructure

Class

Proposed

A generalized shear displacement structure without any commitment to the internal nature of the structure (anything from a simple, single 'planar' brittle or ductile surface to a fault system with 10's of strands of both brittle and ductile nature). This surface may have some significant thickness (a deformation zone) and have an associated body of deformed rock that may be considered a DeformationUnit

GeomorphologicFeature

Class

Proposed

A geomorphological feature is a linear or areal landform. It may be associated with an underlying GeologicUnit

MappedFeature

Class

Proposed

A MappedFeature is part of a geological interpretation.
It provides a link between a notional feature (description package) and one spatial representation of it, or part of it. (Exposures, Surface Traces and Intercepts, etc)
    * the specific bounded occurrence, such as an outcrop or map polygon
    * the Mapped Feature carries a geometry or shape
          - the association with a Geologic Feature (legend item) provides specification of all the other descriptors
          - the association with a Sampling Feature provides the context and dimensionality
A Mapped Feature is always associated with some sampling feature - e.g. a mapping surface, a section, a Borehole (see BoreHolesAndObservation) etc.  As noted on the diagram, if the associated sampling feature is a Borehole, then the shape associated with the MappedFeature will usually be either a point or an interval. This reconciles the 2-D ("map", section) and 1-D (borehole, traverse) viewpoints in a common abstraction.

GeologicEvent

Class

Proposed

An identifiable event during which one or more geological processes act to modify geological entities. A GeologicEvent must have a specified GeologicAge and may have specified environments and processes. An example might be a cratonic uplift event during which erosion, sedimentation, and volcanism all take place.
Geological history is an ordered aggregation of Geological Event objects, each of which may have an associated Geological Age, Geological Environment, and one or more Geological Process objects. Genesis typically pertains to some geological phenomenon (Geological Structure, Earth Material, Geological Unit, Fossil, etc.)
In GeoSciML 2.0 this ordering cannot be specified.
A GeologicEvent must have a specified eventAge (numericAgeDate, olderNamedAge, or youngerNamedAge), at least one eventProcess, and may have specified eventEnvironments.  An example might be a cratonic uplift event during which erosion, sedimentation, and volcanism all take place. Traditionally, geologists have described the age of a feature without explicitly specifying the event or processes the age related to. The GeologicEvent package allows for explicitly linking the three, without mandating it.
The eventAge attribute is the age of a particular geological event or feature expressed in terms of years before present (absolute age), referred to the geological time scale, or by comparison with other geological events or features (relative age). An eventAge can represent an instant in time, an interval of time, or any combination of multiple instants or intervals. Specifications of age in years before present are based on determination of time durations based on interpretation of isotopic analyses of EarthMaterial (some other methods are used for geologically young materials). Ages referred to geological time scales are essentially based on correlation of a geological unit with a standard chronostratigraphic unit that serves as a reference. Relative ages are based on relationships between geological units such as superposition, intruded by, cross-cuts, or "contains inclusions of".

Borehole

Class

Proposed

A borehole is the generalized term for any narrow shaft drilled in the ground, either vertically or horizontally.

BoreholeCollar

Class

Proposed

A Borehole Collar is a feature corresponding to the start point of a borehole.
These are often plotted on a map.  If a text descripiton of the location is available, which should be placed in the gml:description for that feature.
If no GM_Point is available, URN:CGI:unknown should be used
Implementers delivering 3-D collar locations should provide and elevation to improve interoperability.