Relations between climatic fluctuations, carbon cycle perturbations and carbonate production crises : focus on the early cretaceous
type: Dataset
description: The Early Cretaceous is punctuated by carbon cycle perturbations, associated with organic matter burial episodes and carbonate production crises. These events coincide with short-term cooling (<1Ma), yet the mechanisms are still unclear, because of low resolution in sea surface temperature reconstructions. Recent climatic models suggest that carbonate-platform-collapse events may trigger a short-term ocean cooling episode (Donnadieu et al., accepted). In order to establish relations between climates and carbonate productions, we performed stratigraphic, palaeoecologic and geochemical analyses on Valanginian sediments from the La Charce-Vergol and the Ollioules sections (South-East France) and Aptian sedimentary record of the Galvé subasin (North East Spain). Therefore, high-resolution sea surface temperature curves were reconstructed with regard to the pelagic and neritic carbonate producer evolution. Both Valanginian and Aptian stages are marked by polyphased neritic production drawdown. Moreover, the Late Valanginian, basal and latest Early Aptian carbonate-platform demises predate a short-term cooling occurrence. The chronology of these events may imply that carbonate production decrease may have affected the atmospheric CO2 pool and the climate. Nevertheless, the decreases of water temperature that took place in the Late Valanginian and the latest Early Aptian are also prior to episodes of continental and oceanic organic matter burial, respectively. This process is also known as a CO2 drawdown and cooling generator. The present study allowed establishing climate feedbacks on the pelagic and neritic carbonate producers triggering fluctuations of the carbonate production fluxes. At first, cooler conditions during the Late Valanginien and latest Early Aptian are posterior to floro-faunal changes characterised by heterozoan to photozoan replacements. These suggest a trophic level decrease relative to cool and dryer climatic condition. Subsequently, nannoconid commun…
identifier: NNT: 2011DIJOS004
issued: 2026-05-15T21:58:28.623317
language: fr
modified: 2026-05-15T21:58:28.623323
contact point: Organization
  fn: CCSD
keyword: aptian
keyword: aptien
keyword: carbonate-platform-demise
keyword: climat
keyword: climate-carbonate-production-interaction
keyword: crise-des-plates-formes-carbonatees
keyword: infoeu-reposemanticsdoctoralthesis
keyword: interaction-production-carbonatee-climat
keyword: sdustusciences-of-the-universe-physicsearth-sciences
keyword: short-term-cooling
keyword: theses
keyword: valanginian
keyword: valanginien
landing page: https://theses.hal.science/tel-00705496

Relations between climatic fluctuations, carbon cycle perturbations and carbonate production crises : focus on the early cretaceous
type: Distribution
format: HTML
issued: 2026-05-15T21:58:28.627854
modified: 2026-05-15T21:58:28.591566
access URL: https://theses.hal.science/tel-00705496

test_moissonnage_selune
type: Agent