| 研究実績の概要 |
During this final year of the project, we carried out a field season in the Uyuni and Coipasa areas for a period of two weeks. We also continued to analyse the samples collected in previous field studies. In particular to measure the isotopic compositions of the tufa samples to determine the age of formation. We also examined effective ways to plot the elevation data collected from the GPS work. Progress was made in three activities. 1) A new survey completed profiles in areas distant from the main center of the salt flat basins. In particular we examined profiles and shorelines in the Cerro de Empexa area that were previously identified as showing good shorelines from remote sensing. These areas are important because they are least likely to be affected by uplift due to the reduction of the water load on the basin. The heights of shorelines in these regions therefore form an excellent baseline to compare other results. 2) New analyses of seven samples collected from the field work were carried out including thin section making, point counting and 14C dating. 3) Correlating shorelines identified in different profiles is not always easy. To examine the lateral extent of shorelines, we used an airborne drone equipped with cameras. The resulting photography was used to construct a digital elevation model for selected areas.
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