Levantamento Gravimétrico do Setor Setentrional do Cinturão Orogênico Araguaia, Região Centro-Norte do Brasil
Bibliographic record
Abstract
O levantamento gravimétrico envolvendo toda a porção setentrional do Cinturão Orogênico Araguaia, localizado na porção centro-norte do território brasileiro, foi desenvolvido ao longo de rodovias regionais, com espaçamento médio entre as estações da ordem de 5 km. A área envolvida está compreendida pelas coordenadas 4o5' e 9o00' de latitude sul, e 47°50' e 50°30' de longitude oeste. O mapa Bouguer resultante apresenta feições predominantemente submeridianas, destacando-se uma anomalia negativa central da ordem de -107 mGal, assim como um eixo anômalo positivo oriental. A construção de um perfil com direção aproximadamente E-W, transversal à estruturação geral do cinturão orgânico, mostra uma marcante anomalia dipolar com estreita similaridade àquelas documentadas no Canadá, África e Austrália, para zonas de sutura. As anomalias positivas observadas ao longo desse eixo oriental encontram-se intimamente correlacionadas à existência de uma série de estruturas dômicas (braquidobras) ocorrentes ao longo desse eixo, nas quais estão expostos núcleos gnáissicos representativos do embasamento. Foi elaborado um modelo 2.1/2-D, ao longo de um perfil transversal às estruturas, considerando o pacote de supracrustais, intrusões de corpos máfico-ultramáficos e intrusão de uma massa densa na crosta siálica, ao longo de rampas imbricadas de E para W, de conformidade com a situação geológica observada.GRAVITY SURVEY OF NORTHERN ARAGUAIA BELT: BRAZIL A gravity survey was conducted over the Araguaia Orogenic Belt in north-central Brazil, using a nominal 5 km spacing along accessible roads. The region surveyed extends from 4.83 to 9.00 deg. S latitude and 47.83 to 50.50 deg. W longitude. The Bouguer anomaly contour map shows prominent features elongated in the N-S direction and has a total relief of 103 mGal. One approximately E-W profile, transverse to the fold belt, was constructed. This profile shows marked dipolar or paired anomalies very similar to those documented in Canada, Africa and Australia for suture zones. This profile reveals a positive feature which is directly related to a N-S line of doubly-plunging anticlines and domes, some of which are gneiss-cored. A 2.1/2-dimensional model including crustal thickening and upthrusting of denser lower crust from E to W explains the observed profile.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".