PIXE Study Of Lacustrine Sediments Including A Sediment Core From Lake Maicuru, Para, Brazil

摘要

PIXE (Particle Induced X-ray Emission) measurements are reported on downcore sediments from Lake Maicuru, a remote lake in the Amazon Basin. We validate the method by comparison of previously obtained wet chemistry/ICP elemental analysis of sediment from four different lakes with elemental analysis obtained by PIXE measurement. Statistical analysis of results from both methods suggests that PIXE analysis works well for heavier elements (Fe, K, and Ca) but poorly on lighter elements (Na, Mg, and P). The sample preparation procedure developed to deal with the hydrophobic nature of the Maicuru sediments is discussed. Changes in the downcore elemental distribution of Ti, Fe, Mn, and Zn in the lake Maicuru sediments are remarkably similar. The control of this parameter is uncertain but is probably due to climatic changes and water availability and weathering. The good comparison of PIXE and ICP for heavier elements and the consistent results on the downcore study suggests that the PIXE technique holds promise for geochemical and paleoenvironmental studies.