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LITHOEN

Geological region

Yilgarn Craton

An Archean craton of Western Australia. Its Eastern Goldfields region hosts nickel sulfide deposits associated with komatiite lavas, and its weathering profiles host nickel-cobalt laterites — two entirely different mineral systems on the same ancient crust, separated by billions of years.

Classification

region kind
craton
domain realm
australia

How this is mapped

One published representation of where Yilgarn Craton is. Each is one interpretation, by one identified source, at one scale — not the shape of the thing itself.

  • Published interpretive extent

    Polygon · 243 positionspreferred for publication

    An extent published by an identified author or group as their interpretation. It is citable, reproducible and attributable, and it is one reading rather than the reading. Most extents in a geological corpus are this.

    The extent Geoscience Australia maps for the Yilgarn Craton, generalised for display. The source polygon carries the FULL extent of the province including where it lies beneath younger cover, so this outline is not a map of where Archean rock reaches the surface. It was captured at about 1:1,000,000 for use between 1:2,000,000 and 1:5,000,000: at this scale the line is a province boundary, not a contact anyone could walk to. A point inside it is inside a mapped province and is not thereby standing on Archean rock.

    Boundary certainty
    InterpretedThe boundary was placed by a geologist reading evidence: mapping, geophysics, geochronology, structure. It is reproducible from that evidence and it is an interpretation of it. Most geological boundaries are this.
    Status of this geometry
    inferredThe status of the geometry, which need not match the status of what the entity’s claims assert.
    Source scale
    1:1000000
    Dataset
    Australian Geological Provinces — Archean to Proterozoic tectonic provinces (layer 20)© Commonwealth of Australia (Geoscience Australia) 2018, CC BY 4.0. Australian Geological Provinces Database, edition 2013.01.

    What was done to this geometry

    • By Lithoen — EPSG:4283 (GDA94) to EPSG:4326 (WGS84): NO coordinate change was applied, and that is the decision this entry records. At the 2020 epoch the two datums differ by of the order of a metre, while this linework was captured at about 1:1,000,000, where a drafting error of half a millimetre is 500 m on the ground. Shifting the coordinates by a metre would move them without improving them and would imply a datum control the source does not claim. The stored ordinates are the source ordinates, rounded; the accepted error is the datum offset, about 1 m, which is roughly one five-hundredth of the linework’s own resolution.
    • By Lithoen — Douglas–Peucker, 3815 positions to 243
    • By Lithoen — Coordinates rounded to 4 decimal places, about 11 m of longitude at the equator.
    • Before it reached Lithoen — Compiled by Geoscience Australia at approximately 1:1,000,000 for intended use between 1:2,000,000 and 1:5,000,000, from the studies each province record cites.
    • Before it reached Lithoen — The captured extent is the full two-dimensional extent of the province INCLUDING where it lies beneath younger cover. It is not a map of surface exposure.

How this record is known

5
Settled consensus
Cited as the accepted position of the discipline.
1
Interpretation
Reached by reasoning from evidence, or produced by a named model.

6 of 6 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.

What Lithoen records

Each claim states how it is known and cites its evidence.

EstablishedSetting is a statement about a time; the same crust passes through several.

A region’s tectonic setting is a statement about an interval, not a property of the rock. The Yilgarn Craton hosted komatiite volcanism and magmatic nickel sulfide systems in the Archean, and hosts nickel-cobalt laterites developed by tropical weathering in the Cenozoic. Two mineral systems, the same crust, and settings with nothing in common.

  • precision note: This is why Lithoen models tectonic setting as a temporally scoped claim rather than as an attribute of a region: an attribute would have to be true always.

Evidence support: Supported by the cited evidence 2 sources, multiple sources, independence unknown

Evidence: Schulz 2014 Primary authority; Marsh 2013 Primary authority

Established3,730–2,623 Ma before present

Reported for this deposit

The Yilgarn Craton spans the Eoarchean to the Neoarchean: Geoscience Australia gives an older age of 3,730 ± 6 million years, determined by U/Pb ion probe, and a younger age of 2,623 ± 2 million years. These two figures bound the province. Neither is an age of formation for the craton as a whole, and nothing between them is thereby dated.

  • assertion basis: SOURCE_REPORTED
  • method: The older age is given as "isotopic, U/Pb ion probe". The compilation states no method for the younger age.
  • precision note: The compilation records an error on each bound — ±6 Ma on the older, ±2 Ma on the younger — which the geologic-interval value type has no field to carry. Both are stated here in words and neither has been discarded.
  • non uniqueness: A bounding pair, not a duration measurement. The craton was not dated at 3,730 Ma and again at 2,623 Ma as one event with an interval between.

Evidence support: Supported by the cited evidence one source

Evidence: Geoscience Australia 2018 Primary authority

Establishedtectonic province, subtype craton, rank superprovince; six terranes

How a source classifies it

Geoscience Australia records the Yilgarn Craton as a tectonic province of subtype craton, ranked a superprovince, onshore in Western Australia, and describes it as consisting of six terranes — Narryer, Southwest, Youanmi, Kalgoorlie, Kurnalpi and Burtville — the last three of which make up the Eastern Goldfields Superterrane. The record is marked QA-checked and was compiled in 2009 from a Geological Survey of Western Australia field guide.

  • assertion basis: SOURCE_CLASSIFICATION
  • source record: Australian Geological Provinces layer 20, feature GA.GeologicProvince.464632.
  • precision note: The compilation attributes the description to Wyche (2008), a Geological Survey of Western Australia record Lithoen has not retrieved.

Evidence support: Supported by the cited evidence one source

Evidence: Geoscience Australia 2018 Primary authority

EstablishedFull 2D province extent including sub-cover; captured ~1:1M, intended 1:2M–1:5M

Reported for this deposit

A property of a dataset or model, shown here for context — not an observation about this record.

The polygon Geoscience Australia maps for the Yilgarn Craton is the full two-dimensional extent of the province including where it lies beneath younger cover, not a map of where Archean rock reaches the surface. The data was captured at about 1:1,000,000 and is intended for use between 1:2,000,000 and 1:5,000,000. A point falling inside this polygon is inside a province boundary at that scale; it is not thereby standing on Archean rock, and no host lithology follows from it.

  • assertion basis: SOURCE_REPORTED
  • generality: DATASET_PROPERTY
  • precision note: Both statements are the publisher’s. The consequence drawn in the last sentence is Lithoen’s reading of them and is stated as a limit on use, not as a finding.

Evidence support: Supported by the cited evidence one source

Evidence: Geoscience Australia 2018 Primary authority

InferredMurrin Murrin; Bulong; Cawse

Derived by Lithoen

Three of the deposit points Lithoen holds fall inside the extent Geoscience Australia maps for the Yilgarn Craton: Murrin Murrin, Bulong and Cawse. Two others in Australia fall outside it — Brolga, in Queensland, and Whim Creek, in the Pilbara. Lithoen computed this; neither source states it. It is a relationship between two published geometries and nothing more. The province polygon carries the full extent including where the craton lies beneath younger cover, it was captured at about 1:1,000,000, and each deposit point is a representative point from a compilation that states no positional accuracy. No host rock, no host age and no genetic relationship follows from a point being inside a line.

Not stated verbatim by the source — derived: point ∈ polygon (ray casting, EPSG:4326), evaluated for five deposit representative points against the unsimplified GA.GeologicProvince.464632 ring

Neither source asserts this relationship; Lithoen computed it from published geometries, and the operation is named so a reader can re-perform it. It is recorded as a derivation precisely so it can never be mistaken for a geological statement either source made. The two negative results are carried in the claim for the same reason.

  • assertion basis: LITHOEN_DERIVED
  • method: Ray casting in EPSG:4326 decimal degrees against the unsimplified source ring of feature GA.GeologicProvince.464632 (3,815 positions), re-run against the published simplified ring (243 positions) as a stability check. All five answers agree between the two geometries, so the result does not depend on the generalisation.
  • assumption: That a representative point stands for its deposit well enough for a containment test at this scale. None of the five lies near the province boundary, so no answer turns on a position the compilations never guaranteed. A point close to the line would not support this.
  • precision note: Containment in a mapped province is not containment in a rock unit. The polygon includes sub-cover extent and is a province boundary at 1:1M, not a contact. The two deposits outside are reported because a containment result with the negatives withheld is a filter, not a finding.
  • non uniqueness: The value carries the deposit points that fall inside. Two further Australian deposit points were tested and fall outside — Brolga, in Queensland, and Whim Creek, in the Pilbara Craton — and they are named in the statement. A containment result published with its negatives withheld is a filter, not a finding.
  • precision note: Phase 12 closed the limitation this claim was published with. Each point’s distance to the mapped boundary was computed and compared with a tolerance built from what the sources state — half a millimetre of drawn line at the 1:1,000,000 capture scale, about 500 m, plus the 0.01-degree generalisation applied to the published geometry, about 970 m at this latitude. The tolerance is roughly 1.5 km. The nearest of the five points, Bulong, lies 143 km from the boundary; the others are 214 km, 248 km, 480 km and 2,445 km away. Every verdict is therefore CLEARLY_INSIDE or CLEARLY_OUTSIDE with two orders of magnitude to spare, and none of them turns on where the line was drawn. The tolerance remains a floor rather than a total: no compilation states a positional accuracy for these deposit points, so that term could not be included and the record says so.

Evidence support: Derived from the cited evidence one source

Evidence: Geoscience Australia 2018 Primary authority

EstablishedArchean komatiite-hosted sulfides and Cenozoic weathering profiles, on the same crust.

The Yilgarn Craton of Western Australia hosts two mineral systems separated by most of Earth history. Nickel sulfide deposits in the Eastern Goldfields region are associated with Archean komatiite lavas, occurring at or near the base of ultramafic sequences in trough-like structures. Nickel-cobalt laterites such as Murrin Murrin developed by weathering of komatiites and cumulates that are now part of the stable craton.

Evidence support: Supported by the cited evidence 2 sources, multiple sources, independence unknown

Evidence: Schulz 2014 Primary authority; Marsh 2013 Primary authority

In the knowledge graph

Record last updated 2026-09-07. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.