ourtime visitors
Shipment from fresh air isotopes in water people from Drake Passing and the Southern Atlantic
Centered on Schmidt (1999) SCHMIDT GA, BIGG GR and you can ROHLING EJ
In oceanic regions with a positive E-P (Evaporation-Precipitation) balance, there is enrichment in the superficial ocean layer due to preferential evaporation of the lighter species ( Meredith MEREDITH MP, GROSE KE, MCDONAGH EL, HEYWOOD KJ, FREW RD and DENNIS PF. 1999. J Geophys Res Oceans (1978–2012) 104(C9): 20949-20962. et al. 1999). On the other hand, river discharges, high precipitation and ice melting are related to regions with depleted values of ? 18 Osw ( Redfield REDFIELD AC and FRIEDMAN I. 1965. Factors affecting the distribution of deuterium in the ocean. In Symposium on Marine Geochemistry. Rhode Island University Narragansett Marine Laboratory Occasional Publication, Vol. 3, p. 149-168. and Friedman 1965). On a geologic time scale, the glacial boundary conditions influence the isotopic composition of the oceans due to the storage of lighter ? 18 O and ?D isotopes in the ice sheets, which is known as global ice volume effect. However, during interglacial periods, this effect was reversed (Holloway et al. 2015).
Because salinity and ? 18 Osw are controlled by the same processes, they show a quasi-linear relationship, and the slope is dependent on the kinetic processes acting in the water mass formation area. 2015. Differences among subtropical surface salinity patterns. Oceanogr 28(1): 32-39. 1965). 1999. Global Seawater Oxygen-18 Database – v1.21. , the global mixing line between ? 18 Osw and salinity can be used as an approximation only in mid to high latitudes, since the scatter for the tropical samples could be up to 0.13‰. Therefore, regional mixing lines become essential pieces in paleoclimatic studies in the equatorial and tropical regions. Holloway et al. (2015) suggested that regions with marked variability in the evaporation-precipitation budget and strong oceanographic dynamics need additional constraints to establish good salinity and ? 18 Osw relationships on spatial and temporal scales. On the other hand, South Atlantic, Indian and Tropical Pacific Oceans have more reliable paleosalinity reconstructions without the need of additional constraints.
Despite the importance of the Southwest Atlantic Ocean for thermohaline circulation and the global climate through in the South Atlantic Meridional Overturning Circulation (SAMOC), only a few studies have been carried out in this area using stable isotopes. For example, GEOSECS was conducted in the South Atlantic focusing on open waters (Kroopnick 1980, Ostlund OSTLUND HG, CRAIG H, BROECKER WS and SPENCER D. 1987. GEOSECS Atlantic, Pacific and Indian ocean expeditions, shorebased data and graphics, Vol. 7. Technical report, I.D.O.E. National Science Foundation, ourtime p. 200. et al. 1987) and an independent work of Pierre et al. (1991) focused on a small offshore area of the southwestern Atlantic. None of these papers were focused on paleoclimatic applications. The aim of the present study was to investigate the distribution of the stable isotopes (? 18 Osw and ?Dsw) at the Western Tropical South Atlantic border, from the continental shelf to slope, in order to better understand the main fractionation processes of these isotopes and establish a regional salinity and ? 18 Osw relationship to improve paleoceanographic knowledge in the study region.
After that, following the liquids size basins, the connection stays secure on h2o bulk existence (Craig and Gordon GORDON AL, GIULIVI CF, BUSECKE J and you will BINGHAM FM
The newest eastern Brazilian continental margin is common for the less thickness and you can superficial depths in comparison to other areas of the Southwest Atlantic margin, because of reasonable continental erosion speed additionally the brief part of aquatic sedimentation. Likewise, the ceaseless exposure of the Brazil Most recent flowing for the southwest synchronous on the bookshelf additionally the Northern Brazil Most recent flowing equatorward moving warm and you will saline Exotic Drinking water supplies the part a generally oligotrophic character, and that decreases this new genesis of biogenic material that comprise extremely of sedimentary bottoms from the southeastern Brazilian continental shelf ( Knoppers KNOPPERS B, EKAU W and you will FIGUEIREDO AG. 1999. The new shore and you can shelf from eastern and northeast Brazil and topic transport. Geo-Marine Lett 19: 171. mais aussi al. 1999). New bifurcation of the South Equatorial Most recent (SEC) happen at about 10°–14°S close to the skin and continental bookshelf thickness differs from 42 kilometer out-of Maceio to eight kilometer away from Salvador, having an average of 31 kilometres ( Fig. 1).
