288 resultados para 35.182.327
em Publishing Network for Geoscientific
Radiocarbon dating, sedimentation rate, granulometry and organic carbon content of ODP Leg 182 sites
Resumo:
This data report presents sedimentological (grain size) and geochemical (X-ray diffraction, total organic carbon, accelerator mass spectrometry radiocarbon, and percent carbonate) information obtained from the western transect (Sites 1132, 1130, and 1134) and the eastern transect (Sites 1129, 1131, and 1127) in the Great Australian Bight during Leg 182. The purpose is to quantify changing rates of sediment accumulation and changes in sediment type from the late Pleistocene and Holocene, in order to relate these changes to the well-known sea level curve that exists for this time frame. Ultimately, these data can be used to more effectively interpret lithologic variations deeper in the Pleistocene succession, which most likely represent orbitally forced sea level events.
Resumo:
This report presents mineralogic and geochemical data from Ocean Drilling Program Leg 182 Site 1128 in the Great Australian Bight. Clay mineralogy is dominated by mixed-layer illite-smectite, followed by minor amounts of kaolinite and illite, with intervals of pure smectite. Carbonate mineralogy is exclusively low-Mg calcite, except for one interval of dolomite in lower Oligocene sediments. Carbonate increases significantly in upper Eocene sediments, decreases through the lower Oligocene, then increases again in the Neogene. Quartz is present as a minor component that covaries inversely with carbonate. High-resolution sampling associated with Chron 13 normal (early Oligocene) reveals high-frequency (~23 k.y.) fluctuations in clay mineralogy and carbonate abundance and a positive oxygen and carbon isotope excursion (in bulk carbonates) related to Antarctic glaciation.
Resumo:
At present time, there is a lack of knowledge on the interannual climate-related variability of zooplankton communities of the tropical Atlantic, central Mediterranean Sea, Caspian Sea, and Aral Sea, due to the absence of appropriate databases. In the mid latitudes, the North Atlantic Oscillation (NAO) is the dominant mode of atmospheric fluctuations over eastern North America, the northern Atlantic Ocean and Europe. Therefore, one of the issues that need to be addressed through data synthesis is the evaluation of interannual patterns in species abundance and species diversity over these regions in regard to the NAO. The database has been used to investigate the ecological role of the NAO in interannual variations of mesozooplankton abundance and biomass along the zonal array of the NAO influence. Basic approach to the proposed research involved: (1) development of co-operation between experts and data holders in Ukraine, Russia, Kazakhstan, Azerbaijan, UK, and USA to rescue and compile the oceanographic data sets and release them on CD-ROM, (2) organization and compilation of a database based on FSU cruises to the above regions, (3) analysis of the basin-scale interannual variability of the zooplankton species abundance, biomass, and species diversity.