A Palaeo Environmental Assessment Of Sediments Environmental Sciences

Essay add: 12-10-2017, 20:46   /   Views: 8

This palaeo-environmental reconstruction is based upon using a multi-proxy approach to analyse lake sediments. The lake of Wuxu-hai lies in the Province of Yunnan, southwest China (figures 1 and 2) and consists of a single basin measuring 1.7km2 situated at an altitude of 3630m a.s.l. It is thought that Wuxu-hai Lake was formed by glacial processes during the Last Glacial Maximum (LGM).

At present, the catchment lies in a sub-alpine vegetation belt situated at 250m below the current treeline. The vegetation is primarily comprised of coniferous forest (Pinus, Picea and Abies), deciduous and evergreen Quercus. The area above the current treeline is dominated by grassland steppe.

1.2. Materials, Methods and Techniques

In 2008 a 6.5 m core was extracted from the centre of Wuxu-hai Lake and sub-sampled at a resolution of 2cm, using a multi-proxy approach, involving a variety of lithological and biological techniques. Vegetation cover reconstruction within the lake catchment is inferred from changes in the pollen concentrations of species over time (Pinus, Quercas, Artemisia and Poaceae). Loss on Ignition (LOI) has been carried out to determine the organic content of the core. Furthermore, Mineral Magnetic Analysis (Xlf) has taken place in order to determine the total magnetic composition of the bulk sediment. Finally, Micro Charcoal analysis (grains/cm3) has been used to reveal counts of micro charcoal, providing a record of past fire events within the catchment.

Figure 1: Map illustrating the Figure 2: Detailed map of Yunnan

Provinces of China.

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