The role of scavenging and early diagenesis in controlling hydrothermal fluxes into the ocean along the Endeavour segment of the Juan de Fuca ridge
Notice bibliographique
Résumé
Mixing of high-temperature hydrothermal vent fluids with seawater leads to the precipitation of a large fraction of the non-conservative element load and scavenging of elements from seawater onto the particles formed. This substantially modifies hydrothermal fluxes into the ocean relative to the flux across the seafloor at vents. However, the particles formed in the plume are rarely in equilibrium within the uppermost sediments, and scavenged elements may be loosely bound to particle surfaces, meaning that the net flux from the ocean can be readily modified by processes operating during early diagenesis. Using bulk geochemistry, and progressive leaching experiments, we characterize sediments from around the Endeavour segment of the Juan de Fuca ridge to investigate scavenging and early diagenetic processes. Changes in bulk sediment composition with distance from the ridge (e.g., decreases in Fe/Ti) support a decreased hydrothermal input off-axis. Bulk-sediment and leachate data are interpreted as indicating substantial scavenging of elements such as P, V, Cr and REEs as previously suggested, with different elements scavenged with different efficiencies in different parts of the plume. Correlations of these elements with Fe in the HCl leachates, suggests their uptake is associated with Fe-oxyhydroxides. Water column scavenging is overprinted by fluxes associated with benthic scavenging for V and REE. In contrast, early diagenesis leads to complete loss of scavenged P back to the ocean. Leaching the samples with NaOH and acetic acid provides evidence for recrystallization of reactive (biogenic and hydrothermal) silica and CaCO 3 during early diagenesis in all locations. The fraction of Fe and Mn leached by 1 M HCl in 1 h versus 24 h, and the amount leached in 24 h, vary systematically; these data can be explained by progressive recrystallization of hydrothermally-derived Fe and Mn minerals during early diagenesis. These early diagenetic reactions release almost all hydrothermally-derived Mn back into the ocean, while Fe remains largely fixed in the sediment. Large-scale loss of Co, Zn, Mo, Ag and Cd also occurs during early diagenesis, with some evidence As, Pb and U are also lost. In deeper, more reducing, sediments there is uptake of As, Mo, Ag, Cd and U, presumably via diffusion through the shallow oxic sediments. Such diagenetic processes mean that the net fluxes of elements into and out of the ocean associated with hydrothermal systems differ from those estimated from studies of either vent fluids or hydrothermal plumes. • Progressive leaching helps unravel the evolution of hydrothermal particles. • The fraction of reactive Fe varies systematically with distance from axis. • The fraction of reactive Fe varies systematically with depth in cores. • Early diagenesis plays a key role in controlling hydrothermal fluxes.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».