Sn-W-Mo polymetallic behaviour during magmatic evolution of Late Devonian Mount Douglas leucogranites, southwestern New Brunswick, Canada
Bibliographic record
Abstract
The Mount Douglas intrusive suite consists of an assemblage of peraluminous leucogranites located along the eastern part of the Saint George Batholith in southwestern New Brunswick, Canada. This late Devonian suite extends from Red Rock Lake to Mount Douglas, and is interpreted to represent the subvolcanic portion of the Mount Pleasant Sn-W-Mo-Bi-In-Zn deposits. The magmatic systems in the Mount Douglas suite have undergone extreme differentiation producing three distinct phases, including Dmd1, Dmd2, and Dmd3, and are associated with various granophile-element occurrences, such as Sn, W, and Mo. It seems the three phases might originate from a single source that evolves with increasing fractionation from the earliest unit (Dmd1) to the youngest unit (Dmd3). Metal behavior during fractional crystallization is one of the most important factors affecting the types of mineral occurrences associated with the Mount Douglas granites. To establish the metal behavior in the Mount Douglas suite, analytical data from Malcolm McLeod's 1990 report was used in this study. The most incompatible element, Ta, has been selected for defining partition coefficients (D) using the Allegre method. Based on their D values, as expected, Sn with Rb, Y, Nb, LREE [La, Ce, Nd, and Sm], HREE [Tb, Dy, Tm, Yb, and Lu], Pb, Th, and U behave as incompatible elements; showing the Mount Douglas Granite could be considered for exploration of Sn deposits as previous studies have mentioned. However, W and Mo accompanied with the other elements, such as Li, P, Sc, Ti, Cu, Zn, Sr, Zr, Cs, Ba, Eu, and Hf seem to act as compatible elements during magmatic evolution, although melt - supercritical fluid evolution can easily affect W, Mo, Cs, and Li abundances. The apparent compatibility of W and Mo is in contrast with the expected results in which they might act as incompatible elements for developing considerable potential for W-Mo deposits. However, W and Mo concentrations increased with the degree of fractionation and show a significant enrichment in the Mount Douglas granites relative to other granitoid suites in the region; thus their compatibility may be the result of leaching or partitioning out during volatile exsolution, or low pressure fractionation. Furthermore, very low K/Rb (average 102.7), Nb/Ta (? 6.83), and Zr/Hf (? 35.58) ratios, and high Ti/ Sc (125.3 ?) ratio in Dmd3 compared to Dmd1 possibly reflect significant involvement of extreme low T crystal fractionation or even fluid fractionation in the last-stage magmatic differentiation. Consequently, although much more analytical data are needed for exact evaluation of the mineral occurrences in the Mount Douglas Granites, Dmd3 as the most highly differentiated phases might be considered a superior candidate for hosting of Sn-W-Mo deposits.
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 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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".