Shipment from oxygen isotopes in water public out-of Drake Passing additionally the South Atlantic
Considering Schmidt (1999) SCHMIDT GA, BIGG GR and you will 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, 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 liquids bulk sinks, the relationship remains secure on the liquids size life (Craig and you will Gordon GORDON AL, GIULIVI CF, BUSECKE J and you can BINGHAM FM
The newest eastern Brazilian continental margin is common for its smaller thickness and you may low deepness in comparison with http://datingranking.net/es/sweet-pea-review/ other areas of the Southwest Atlantic margin, because of lower continental erosion price additionally the short part of aquatic sedimentation. While doing so, the ceaseless visibility of Brazil Most recent streaming to your southwest parallel with the shelf and also the Northern Brazil Newest streaming equatorward moving enjoying and you may saline Tropical Drinking water offers the region an essentially oligotrophic character, which lowers the latest genesis out-of biogenic thing that define very of sedimentary soles regarding southeastern Brazilian continental shelf ( Knoppers KNOPPERS B, EKAU W and you will FIGUEIREDO AG. 1999. The newest coastline and shelf regarding eastern and you will northeast Brazil and you will issue transportation. Geo-Marine Lett 19: 171. ainsi que al. 1999). The fresh new bifurcation of Southern area Equatorial Latest (SEC) happen at about ten°–14°S near the skin therefore the continental shelf width differs from 42 kilometer off Maceio to eight kilometer out-of Salvador, having typically 30 km ( Fig. 1).
