Paleotopographic evolution of the brazilian continental margin during the Phanerozoic: evidence from apatite fission track thermochronology
Bibliographic record
Abstract
Este trabalho explora banco de dados traços de fissão em apatitas com o objetivo de desenvolver uma visão sinóptica de padrões de denudação através do espaço-tempo na margem continental brasileira. A resposta geomorfológica aos processos de rifteamento e ruptura continental variou ao longo da margem continental brasileira. No processo de construção do relevo desta margem foram registrados três episódios de resfriamento acelerado, que são vinculados a processos denudacionais: Cretáceo Inferior, Cretáceo Superior e Paleógeno-Neógeno. As margens continentais sudeste e leste apresentam uma morfologia de margem continental passiva característica, com as bacias sedimentares offshore separadas da região continental elevada, composta pelas Serra do Mar e da Serra da Mantiqueira, por uma planície costeira relativamente estreita. As idades de soerguimento são mais jovens do que a idade do rifteamento. O resfriamento do Paleógeno-Neógeno é resultado do aumento nas taxas de denudação, que são relacionados à formação e reativação de blocos de falha de alto ângulo que se moveram em resposta às tensões intraplaca. A região do Arco de Ponta Grossa apresenta o relevo mais jovem de toda a margem, sendo um alto topográfico associado ao magmatismo Paraná-Etendeka e limitado por zonas de cisalhamento. Duas porções da margem apresentam relevo diferenciado, com episódios de denudação pré-rifte. A Depressão Sertaneja, na margem nordeste, típica região semi-árida do nordeste caracterizada como um pediplano, com vales estreitos e vertentes dissecadas, com resfriamento do Permiano-Jurássico Inferior; e a margem sul, local com topografia baixa, e soerguimento lento e contínuo do Paleozoico.A B S T R A C TThis study explores apatite fission track database with the objective of developing a synoptic view of denudation patterns across space and time in the Brazilian continental margin. The geomorphological response to the continental rift and rupture processes varied along the Brazilian continental margin. In the construction of the relief of this margin were recorded three episodes of accelerated cooling, which are linked to denudational processes: Lower Cretaceous, Upper Cretaceous and Paleogene-Neogene episodes. The southeast and eastern continental margin presents a characteristic passive continental margin morphology, with the offshore sedimentary basins separated from the elevated continental region, Serra do Mar and Serra da Mantiqueira, for a relatively narrow coastal plain. The uplifting ages are younger than the rift age. Accelerated cooling during Paleogene-Neogene is a result of increased denudation rates, which are related to the formation and reactivation of high angle fault blocks that have moved in response to intraplate stresses. The region of the Ponta Grossa Arch presents the youngest relief of the entire continental margin. It is a high topographic associated with Paraná-Etendeka magmatism and limited by shear zones. There are two parts of the continental margin with differentiated relief, which present episodes of pre-rift denudation. The Sertaneja Depression, in the northeast margin, a typical semi-arid northeast region characterized as a pediplane, with narrow valleys and dissected slopes, where occurs a Permian-Lower Jurassic cooling episode; and the south continental margin, where the topography is relatively, registering a slow and continuous uplift during the Paleozoic. Keywords: Paleotopography, rift continental margin, apatite fission tracks
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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 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".