Association of trace elements with various geochemical phases in the Indian sector of Southern Ocean during past 22,000 years and its palaeoceanographic implications

作者：Sruthi K V; Thamban Meloth^*; Manoj M C; Laluraj C M

来源：Current Science, 2012, 103(7): 803-809.

• Last Glacial Maximum
• redox condition
• sequential extraction
• Southern Ocean
• trace element

Adopting sequential extraction procedures, Ba, Cu, Mn, Ni, V and Zn concentrations were determined in the moderately reducible, organically bound, carbonate-associated and adsorbable fractions within a sediment core collected from the Indian sector of the Southern Ocean. The elemental abundances were studied with reference to the Last Glacial Maximum (LGM), deglaciation and Holocene periods. The study showed, with the exception of Ba, elemental abundances in the following order: moderately reducible > organically bound > carbonate-associated > adsorbable fractions. Ba showed high affinity to organically bound and carbonate-associated fractions. Ba concentration revealed large variability (200-1400 ppm) within the carbonate-associated fraction and is related to the reduced carbonate productivity during LGM and increased carbonate productivity during deglaciation as well as Holocene intervals. The relative increase in the concentration of V, Mn and Ni in the reducible fraction suggests enhanced suboxic conditions during LGM. The decreased concentrations of V, Mn and Ni during the deglaciation and late Holocene indicate oxygenated conditions. The suboxic conditions during LGM could be attributed to reduced ventilation resulting from reduced strength of the global thermohaline circulation at this time interval.

• 出版日期2012-10-10