Abstract: A geological map of the Jurassic North Mountain Basalt, southern Nova Scotia: a 200 km transect from Cape Split to Brier Island
Bibliographic record
Abstract
The fi rst regional map showing the distribution of the three fl ow units comprising the Jurassic North Mountain Basalt from Cape Split southwestward to Brier Island is presented. Along this 200 km traverse the NMB is divided into three continuous volcanological fl ow units that have a ca. 500 m aggregate thickness and are referred to as the lower(LFU), middle(MFU) and upper(UFU) units. Exceptional volcanological features of the units are displayed along continuous cliff faces bordering the Bay of Fundy and in numerous quarries. The LFU (≤180 m) is a massive, medium-grained, dominantly holocrystalline basalt with well-developed polygonal jointing (i.e., columnar joints ≤2 m) of colonnade and complex entablature patterns. Several features distinguish the upper part of the fl ow: (1) the upper 5–10 m is fi ner grained and rarely red-brown; (2) the upper 5–10 m may be amygdaloidal; and (3) layered pegmatites locally occur in the upper 30–40 m. These sheet-like layers (≤2–5 cm to ≤1–3 m) are comb-textured and pyroxene-rich with a granophyric matrix and concordant or discordant rhyolite or granophyre seams (≤3 cm) occur. The presence of circular structures, now water-fi lled in some cases, along the central and western parts of the map area may refl ect outpouring of the LFU over water-rich surfaces resulting in formation of rootless cones. The MFU (≤165 m) contains multiple (≤15–20), thin (≤15–20 m), geometrically-complex fl ow sheets with abundant, zonally-arranged vesicles, now zeolite occluded (i.e., amygdules). Abundant fi eld evidence (e.g, fl ow lobes, stacked lobes, vesicle zonation, tumulis) indicate the MFU consists of infl ated pahoehoe fl ow sheets that formed over days to a few months, but red-brown oxidized tops and “neptunian” dykes in the upper half of fl ows indicate a time hiatus between fl ows. The UFU (≤150 m) contains ≤30–40% mesostasis in a medium-grained, ophitic-textured host. This unit consists of 1 or 2 fl ow sheets and also has colonnade style, polygonal jointing (≤1 m). The lower 10–20 m of the UFU locally contains felsic material (ca. 65–74 wt. % SiO2) in the form of dykes, amoeboid masses and spectacular segregation pipes (3–60 cm; ≤10–15/m2) that are sometimes cored by agate and crystalline silica. The distribution on the fl ow units shows several notable features: (1) the surface exposure of the LFU broads to three times its width in the western part of the map to 3 km; (2) coincident with the latter is a change in thickness (20–35 m to 165 m), number of fl ow sheets (4–6 to 15–20) and
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.008 | 0.001 |
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".