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Bejannin, Simon; Tamborski, Joseph James; Van Beek, Pieter; Souhaut, Marc; Stieglitz, Thomas; Radakovitch, Olivier; Claude, Christelle; Conan, Pascal; Pujo-pay, Mireille; Crispi, Olivier; Le Roy, Emilie; Estournel, Claude. |
Determination of submarine groundwater discharge (SGD) from karstic coastal aquifers is important to constrain hydrological and biogeochemical cycles. However, SGD quantification using commonly employed geochemical methods can be difficult to constrain under the presence of large riverine inputs, and is further complicated by the determination of the karstic groundwater endmember. Here, we investigated a coastal region where groundwater discharges from a karstic aquifer system using airborne thermal infrared mapping and geochemical sampling conducted along offshore transects. We report radium data (223Ra, 224Ra, 228Ra) that we used to derive fluxes (water, nutrients) associated with terrestrial groundwater discharge and/or seawater circulation through the... |
Tipo: Text |
Palavras-chave: Submarine groundwater discharge; Mediterranean sea; Radium isotopes; Thermal infrared remote sensing; Nutrient fluxes; GEOTRACES. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00610/72171/70945.pdf |
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Dekov, Vesselin M.; Barry Maynard, J.; Kamenov, George D.; Rouxel, Olivier; Lalonde, Stefan; Juranov, Sava. |
The large manganese (Mn) deposit at Obrochishte (NE Bulgaria) is part of a cluster of similar Early Oligocene deposits located around present-day Black Sea. They collectively constitute the Earth’s second largest endowment of Mn, after the Kalahari Manganese Field in Africa. We have employed a battery of isotopic techniques (C, O, Fe, Sr, Nd, Pb) to help understand the genesis of this deposit. Carbon isotope data indicates that some sections of the Mn-ore layer have diagenetic MnCO3 mineralization, formed by reaction of Mn oxides with organic carbon (Corg), whereas other sections have MnCO3 precipitated directly from the seawater column. Oxygen isotopes show that the high-grade Mn mineralization had seawater as the fluid source, whereas some lower-grade... |
Tipo: Text |
Palavras-chave: Mn metallogenesis; C-O-Fe-Sr-Nd-Pb isotopes; Early Oligocene; Submarine groundwater discharge; Water column anoxia; Proto-Black Sea geochemistry. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00624/73591/73025.pdf |
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