Each claim states how it is known and cites its evidence.
InferredA drawn boundary may be observed, inferred, conventional or model-defined — and looks identical either way.
General principle, shown here for context — not an observation about this record.
Most geological boundaries are interpretations rather than observations. A line on a geological map may be a contact somebody walked, a change inferred from geophysics beneath cover, a gradation over tens of kilometres drawn where a convention says to draw it, or a model boundary that exists because the model needs one. These are not equally well known, and a map drawn at one line width cannot tell them apart.
- method: Follows from the retrieved sources: PB2002 states that a boundary class may change along a single segment, and the chromite model places cratons and their margins by describing intrusions rather than by delimiting the cratons.
- precision note: Lithoen therefore stores boundary certainty on each geometry, with GRADATIONAL and CONCEALED as available values, and refuses to publish a geometry that does not state one.
- generality: GENERAL_PRINCIPLE
Evidence support: Supported by the cited evidence · 2 sources, multiple sources, independence unknown
Evidence: Bird 2003 · Primary authority; Schulte 2012 · Primary authority
InferredTopography now and deformation then are different things, and neither implies the other.
A mountain range is present-day topography. An orogenic belt is crust that was deformed, thickened and commonly metamorphosed during a mountain-building episode, and it may have no topography left at all. The Superior Province preserves Archean crust that was once mountainous and is now flat; the reverse also occurs, where relief has causes other than orogeny.
- method: Follows from the sources: PB2002’s subduction criteria explicitly exclude the Alps, Zagros, Pamirs, Himalaya, Tien Shan and Taiwan — all major mountain ranges — showing that relief and boundary process are separately determined.
- precision note: Lithoen keeps MountainRange and GeologicalRegion as separate entity types for this reason and does not equate any pair of them.
Evidence support: Supported by the cited evidence · 2 sources, multiple sources, independence unknown
Evidence: Schulte 2012 · Primary authority; Bird 2003 · Primary authority
InferredSpatial intersection is never evidence of a geological relationship.
General principle, shown here for context — not an observation about this record.
Two mapped regions overlapping is a fact about two polygons. That one region formed the other, reworked it, or hosts anything within it is a fact about the Earth, and needs evidence. Lithoen keeps computational spatial predicates in a separate vocabulary from its geological relations, and derives none of the second from the first.
- method: Follows from how the retrieved sources establish regional relationships: by dating, by structural continuity and by rock associations, never by observing that two areas overlap on a map.
- precision note: Enforced in code: SPATIAL_PREDICATES is a separate vocabulary from RELATION_TYPES, and no validator or projection promotes one into the other.
- generality: GENERAL_PRINCIPLE
Evidence support: Supported by the cited evidence · 2 sources, multiple sources, independence unknown
Evidence: Schulte 2012 · Primary authority; Leach 2010 · Primary authority
EstablishedArchean granite-greenstone terrains, some of them found by aeromagnetic survey.
The Superior Province of Canada contains Archean granite-greenstone terrains. The USGS chromite model places the Bird River Sill in the Archean supracrustal rocks of the Bird River greenstone belt in Manitoba, and the magmatic nickel model places a ring of mafic to ultramafic intrusions within the Sachigo greenstone belt, detected as a semicircular ring of magnetic highs in a regional aeromagnetic survey.
- method: Surface mapping for the Bird River belt; regional aeromagnetic survey for the Sachigo intrusions, which were found as a magnetic pattern before they were understood as a geological one.
Evidence support: Supported by the cited evidence · 2 sources, multiple sources, independence unknown
Evidence: Schulte 2012 · Primary authority; Schulz 2014 · Primary authority