Data/hora: 09/06/2024 13:57:10

Provedor de dados: 	5	
País: 	France	
Título: 	New insights into productivity and redox-controlled trace element (Ag, Cd, Re, and Mo) accumulation in a 55 kyr long sediment record from Guaymas Basin, Gulf of California	
Autores: 	Chang, Alice S.; Pichevin, Laetitia; Pedersen, Thomas F.; Gray, Victoria; Ganeshram, Raja.	
Data: 	2015-02	
Ano: 	2015	
Palavras-chave: 	Productivity; Redox; Trace elements; Laminated sediments; Guaymas Basin; Northeast Pacific Ocean.	
Resumo: 	A high-resolution, 55 kyr long record of chalcophile and redox-sensitive trace element accumulation (Ag, Cd, Re, and Mo) from MD02-2515, western Guaymas Basin, is investigated in conjunction with patterns in stratigraphy and productivity. High opal concentrations (~59 wt. %), representing increased diatom production, coincide with laminated sediments and dilute the concentrations of organic carbon (Corg) and metals. A similarity between opal and normalized Corg, Ag, and Cd concentrations suggests delivery to the sediments by diatom export production, while patterns in normalized Re and Mo accumulation suggest a different emplacement mechanism. Although Mo enrichment in organic-rich, laminated sediments typically represents anoxic conditions at other locations, Mo (and Re) in Guaymas Basin is enriched in nonlaminated and bioturbated sediments that are representative of oxygenated conditions. Adsorption onto Fe- and/or Mn-oxyhydroxide surfaces during oxygenation inadequately explains both the Re and Mo enrichments. Thus, recently published mechanisms invoking direct Re and Mo removal from the water column and bioturbation-assisted irrigation of Re into the sediments are used to explain the counterintuitive observations in Guaymas Basin. The MD02-2515 stratigraphic and proxy records are also different from other records in the northeast Pacific in that there is little correspondence with Greenland Dansgaard-Oeschger interstadials. There is some correlation with Heinrich events, suggesting that ventilation of intermediate waters and/or reduced productivity may be important in controlling stratigraphy and trace element accumulation. The results question whether MD02-2515 records can be compared to northeast Pacific open-margin records, especially before 17 kyr B.P.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	https://archimer.ifremer.fr/doc/00294/40566/39461.pdf

https://archimer.ifremer.fr/doc/00294/40566/39462.doc

https://archimer.ifremer.fr/doc/00294/40566/39463.pdf

DOI:10.1002/2014PA002681

https://archimer.ifremer.fr/doc/00294/40566/	
Editor: 	Amer Geophysical Union	
Formato: 	application/pdf	
Fonte: 	Paleoceanography (0883-8305) (Amer Geophysical Union), 2015-02 , Vol. 30 , N. 2 , P. 77-94	
Fonte: 	2015. American Geophysical Union. All Rights Reserved

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