BRECCIA-HOSTED GOLD ON THE NORTHERN BURIN PENINSULA, NEWFOUNDLAND
Bibliographic record
Abstract
The Lodestar prospect consists of sulphide–oxide mineralized breccias of magmatic–hydrothermal or phreatomagmatic origin. The prospect contains significant gold mineralization within polylithic breccias associated with the Powder Horn Intrusive Suite, near Goobies. The best grades obtained by exploration companies from chip-channel sampling of the mineralized breccia consist of 4.98 g/t Au and 14.8 g/t Ag over a 15.9 m width, along with one area that returned an assay of approximately 2.0 % Zn. Earlier assays returned values of 6.13 g/t Au over 4.7 m and 4.91 g/t Au over 3 m. Recent samples channeled by the owner of the property indicate 5.6 g/t Au over 8.5 m including 12.6 g/t Au over 1 m. The Powder Horn Intrusive Suite is a multi-phase intrusive suite, having both pre- and post-brecciation (mineralization) phases. Pre-mineralization rocks consist of sedimentary units of the late Neoproterozoic Musgravetown Group, which are hornfelsed in areas close to the intrusion, medium-grained gabbro/diorite, and minor felsic material. Post-mineralization phases include fine-grained gabbro/diorite, felsic phases, and diabase dykes. The main mineralized breccia, which occurs at the contact of the host sedimentary rocks and the pre-breccia gabbro/diorite, is exposed over approximately 25 m and contains gold mineralization in association with copper, arsenic, and zinc. The mineralization dominantly occurs as the matrix of the breccia, whereas unmineralized sections of the breccia contain actinolite/chlorite within the matrix. The breccia clasts consist of the host sedimentary material, pre-breccia gabbro/diorite, quartz–feldspar porphyry, diabase, and minor fine-grained granite. The sedimentary and gabbro/diorite clasts were locally derived from the wall-rock, however, the quartz–feldspar porphyry clasts have not been observed in outcrop in the area of the showing and are therefore assumed to be derived from depth. In places, these porphyry clasts contain pre-breccia mineralization, and they also appear to be finely comminuted, thereby producing a rock-flour matrix in portions of the breccia and possibly indicating transportation from depth. Many characteristics of the Lodestar prospect correspond to a magmatichydrothermal origin for the breccia, produced by fluid exsolution from a gold-bearing intrusive system. The presence of exotic mineralized quartz–feldspar porphyry clasts within the breccia suggests that mineralization may be related to a deep Cu–Au porphyry system. If so, the prospect may have formed in a transitional environment between a deep mineralized porphyry system and a shallow epithermal system. The Lodestar prospect is, therefore, very significant because it indicates the potential for additional porphyry-style mineralizatilon within the Powder Horn Intrusive Suite, as well as elsewhere on the Burin Peninsula.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".