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Govin, Aline; Holzwarth, Ulrike; Heslop, David; Keeling, Lara Ford; Zabel, Matthias; Mulitza, Stefan; Collins, James A.; Chiessi, Cristiano M.. |
Numerous studies use major element concentrations measured on continental margin sediments to reconstruct terrestrial climate variations. The choice and interpretation of climate proxies however differ from site to site. Here we map the concentrations of major elements (Ca, Fe, Al, Si, Ti, K) in Atlantic surface sediments (36 degrees N-49 degrees S) to assess the factors influencing the geochemistry of Atlantic hemipelagic sediments and the potential of elemental ratios to reconstruct different terrestrial climate regimes. High concentrations of terrigenous elements and low Ca concentrations along the African and South American margins reflect the dominance of terrigenous input in these regions. Single element concentrations and elemental ratios including... |
Tipo: Text |
Palavras-chave: Atlantic surface sediments; Terrigenous input; Major elements. |
Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00214/32550/31035.pdf |
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Pape, Thomas; Ruffine, Livio; Hong, Wei‐li; Sultan, Nabil; Riboulot, Vincent; Peters, Carl A.; Kölling, Martin; Zabel, Matthias; Garziglia, Sebastien; Bohrmann, Gerhard. |
The evolution of submarine pockmarks is often related to the ascent of fluid from the subsurface. For pockmarks located within the gas hydrate stability zone, methane oversaturation can result in the formation of gas hydrates in the sediment. A ca. 600 m‐wide sea floor depression in deep‐waters offshore Nigeria, Pockmark A, was investigated for distributions and quantities of shallow gas hydrates, origins of hydrocarbons and time elapsed since the last major fluid ascent event. For the first time, pressure coring of shallow sediments and drilling of more than 50‐m‐long cores with the sea floor drill rig MARUM‐MeBo70 were conducted in this pockmark. Unusually high hydrate saturations of up to 51% of pore volume in the uppermost 2.5 meters of sediment in the... |
Tipo: Text |
Palavras-chave: Pockmark; Gas hydrate; Methane; MeBo; Pressure coring; Pore water modeling. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75491/76344.pdf |
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