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Sb-enriched ultramafic lamprophyre in the Hemlo Au-Mo deposit of the Superior Province, Canada Evidence for Post-Archean Sb mobility

2000· article· en· W2341414017 on OpenAlex
Eva S. Schandl, Michael P. Gorton

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
aboutThe title or abstract carries a Canadian signal from the geographic lexicon.

Bibliographic record

VenueEuropean Journal of Mineralogy · 2000
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicGeological and Geochemical Analysis
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsGeologyGeochemistryUltramafic rockOlivineArcheanSillFelsicMafic

Abstract

fetched live from OpenAlex

An Sb-enriched ultramafic lamprophyre (UML) sill was identified within the Hemlo Au-Mo deposit (David Bell mine) of the Superior Province, Canada. The low SiO 2 (31 wt.%), high TiO 2 (4.2 wt.%), Nb (146 ppm), Ta (10 ppm), Cr (900 ppm), and Ni (720 ppm) contents, as well as the unusual mineralogy (olivine, perovskite, Ti-rich phlogopite, calcite) of the sill are consistent with the geochemistry and mineralogy of other ultramafic lamprophyres on the global scale. The fine-grained, dark greenish-black sill has unchilled margins and intrudes basaltic and felsic fragmentals. The lamprophyre contains 794 ppm Sb, which is concentrated in fine-grained ullmannite, a Ni(Co)-Sb sulfide, within pervasively altered olivine. The presence of ullmannite in altered olivine within the UML implies that Sb was mobilized after the emplacement of the sill. Because Sb is considered to be one of the pathfinder elements for Au at Hemlo, and because antimony sulfides (including ullmannite) and arsenides are commonly associated with Au at the Hemlo camp, the addition of Sb to the Proterozoic lamprophyre suggests that Sb mobilization (and by inference, Au) possibly occurred throughout the tectonic evolution of the deposit. This has implications for genetic models of Hemlo, as cross-cutting relationships of Archean plutons and multi-phase deformation of the deposit make it difficult to distinguish between the actual timing of Au, Mo and Sb introduction and their subsequent re-mobilization and re-concentration into structural traps during various stages of deformation. It also re-opens questions concerning the genetic link between gold metallogeny and tectonic evolution of the region.

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.

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)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.367
Threshold uncertainty score0.848

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
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 science0.0010.000
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 head0.018
GPT teacher head0.202
Teacher spread0.184 · 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