THE LONG LAKE GROUP: PRELIMINARY U-Pb GEOCHRONOLOGY AND LITHOGEOCHEMISTRY, AND IMPLICATIONS FOR TECTONOSTRATI- GRAPHIC ARCHITECTURE AND VMS MINERALIZATION
Bibliographic record
Abstract
The Long Lake group forms part of the Victoria Lake supergroup of central Newfoundland and hosts one defined VMS deposit and several other occurrences. The group is dominated by felsic volcanic rocks, and lesser amounts of mafic volcanic rocks and intercalated volcano-sedimentary rocks. The rocks formed, in volcano-sedimentary basins, within active volcanic arcs on the peri-Gondwanan margin of the Iapetus Ocean. The southwestern portion of the Long Lake group is host to the Long Lake main VMS deposit, as well as several other VMS alteration systems and VMS occurrences. Structural overprinting, in the form of folding and faulting, has affected the group and its VMS deposits and occurrences, resulting in strongly attenuated alteration zones and massive sulphide horizons. In conjunction with extremely poor outcrop density, and accessibility challenges, this makes stratigraphic mapping and interpretations difficult. Structural repetition may be important in the case of the Long Lake main deposit. The felsic volcanic rocks of the Long Lake group were originally associated with the rocks of the Tulks Volcanic group to the west; but more recent work assigned all of the felsic volcanic rocks in the group to a single formation; the ca. 506 Ma Costigan Lake formation, which is approximately 11 Ma older than the Tulks Volcanic group rocks. Results of this study suggest that the felsic rocks in the group are more appropriately divided into two main packages: 1) a lower stratigraphic package of ca. 511 Ma fine-grained to aphyric rhyolite and felsic tuff having high concentrations of highfield strength and rare-earth elements, and 2) an upper stratigraphic package of ca. 506 Ma blue quartz-phyric felsic to intermediate tuff having significantly lower concentrations of high-field strength and rare-earth elements. There may also be contrasts in Nd isotopic signatures between the two sequences. Both packages of rocks are now in fault contact but appear to be prospective for volcanogenic massive sulphide accumulations, although their response to typical exploration techniques may be variable.
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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 | 0.000 |
| 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 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".