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Record W2909048635 · doi:10.4095/305828

Musings on intrusion geometry, chonoliths and mineral deposits

2017· report· en· W2909048635 on OpenAlexaffabout
B M Saumur

Bibliographic record

Venuenot available
Typereport
Languageen
FieldEarth and Planetary Sciences
TopicGeological Modeling and Analysis
Canadian institutionsNatural Resources Canada
Fundersnot available
KeywordsIntrusionGeologyGeometryMineralGeochemistryMining engineeringMathematicsMaterials scienceMetallurgy

Abstract

fetched live from OpenAlex

Several types of intrusion-hosted ore-deposits are formed within geometrically complex bodies, and the so-called "space problem" associated with the emplacement of these bodies within the crust is generally poorly understood. Felsic to intermediate porphyry-Cu systems are often hosted within vertical pipes or stocks that are circular to elongate in plan view. Ni-Cu magmatic sulfide deposits are hosted within structurally complex feeder systems. These often have irregular to tube-shaped geometries unlike typical dykes, sills or laccoliths, which has led to the resuscitation, by exploration and economic geologists alike, of the once-obsolete term "chonolith" to characterise such irregular intrusions. Both porphyry-Cu and magmatic Ni-Cu sulfide systems share other first-order similarities, such as late-stage volatile-rich magmas and emplacement within environments of active deformation, indicating that despite their differences emplacement dynamics may be analogous. In many cases irregular intrusion geometries can be explained internal and external structural processes. At Voisey's Bay (Labrador, Canada) for instance, magmatic Ni-Cu sulfides are located within dikes and at the base of a geometrically complex magma chamber. The chamber could, a priori, be termed a chonolith; however, detailed 3D structural analysis of the chamber indicates that it consists of an amalgamation of sill-like magma bodies affected by intermittent local activity of faults. Dike-hosted mineralization is located within thickened portions of feeder dikes, which locally resemble some mafic chonoliths in cross-section. The geometry of these dikes is strongly controlled by the interaction of pre-emplacement wall rock structure with intruding magmas, and dike widening by thermo-mechanical erosion of the surrounding wall rocks. Chonoliths are ideal sites of Ni-Cu-PGE mineralization because they promote high magma fluxes and protracted magma flow-through, thereby favouring the interaction between metal-bearing mafic magmas and sulfide liquids that are progressively enriched in metals. Such processes occur at the relatively local scales of 1-10 km magmatic complexes, and successful exploration must consider small-scale targeting within larger, regional scale igneous provinces. As an example, several magmatic complexes of the High Arctic Large Igneous Province (Nunavut) show first-order architecture that would favour Ni-Cu-PGE potential.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.715
Threshold uncertainty score0.999

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.041
GPT teacher head0.259
Teacher spread0.218 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2017
Admission routes2
Has abstractyes

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