The nature and origin of REE mineralization in the Misery syenitic intrusion, Northern Québec, Canada
Bibliographic record
Abstract
As a result of the recent increase in demand for the rare earth elements, the newly discovered Misery syenitic intrusion is attracting considerable exploration interest. This REE-Zr-Nb prospect is located 200km east of Schefferville and 70km south of Strange Lake in Québec, Canada. It is a 6km wide, ring-shaped intrusion conspicuous on aeromagnetic maps that was emplaced within the Mistastin Batholith, a large Elsonian age granitoid body, which intrudes Paleoproterozoic rocks of the Churchill Province. The Misery intrusion displays a gradational contact with its host, the Misastin rapakivi granite. Both have an A-type affinity and similar trace element composition. The Misery syenites are therefore interpreted to be a late differentiate product of the Mistastin batholith. The dominant exposed lithology (much of the intrusion is covered by a lake) is a felsic syenite, which is mainly composed of perthitic K-feldspar and 1 to 10 volume% of interstitial ferromagnesian minerals, namely fayalite, hedenbergite, ferropargasite and annite (iron rich biotite); the accessory minerals are quartz, iron oxides (magnetite, Ti-rich magnetite and ilmenite), zircon, fluorite, apatite and britholite. A melanocratic unit, ferrosyenite, which contains up to 50 volume % ferromagnesian minerals, including cumulate fayalite and hedenbergite, occurs as amoeboid-like inclusions in the felsic syenite. The ferrosyenite is interpreted to have formed by fractional crystallization of ferromagnesian minerals leaving behind a residual magma which produced the felsic syenites. With continued fractional crystallization, the felsic syenites became more enriched in alkali and silica, and only became saturated with ferromagnesian at a very late stage explaining the interstital crystallization of the latter in the perthite-dominated felsic syenites. The bulk of the REE mineralization (dominantly LREE) is concentrated in pods and layers as hydroxyapatite. Much of this mineralization accumulated through gravity settling in felsic syenite and ferrosyenite, commonly in association with magnetite. The hydroxyapatite crystals were partly or completely replaced by britholite-(Ce), which further concentrated the REE, and crystallized from post-magmatic hydrothermal fluids, which reacted with the magmatic hydroxyapatite. Locally, the felsic syenites underwent sodic metasomatism and where this occurred, the REE were remobilised again to form fluorocarbonate minerals (bastäsite-(Ce), parisite-(Ce) and synchysite-(Ce)). The Misery intrusion and the Mistastin granitoids surrounding it were cut by numerous narrow dykes composed mainly of quartz, fayalite, zircon and fergusonite-(Y). These dykes are interpreted to be products of a FeO-SiO2-rich melt that separated from the main syenite melt and into which Zr and Nb were preferentially fractionated. These dykes represent a new and interesting target for HREE exploration.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".