Study of phosphate layers in Lake Baikal sediments by complex of local methods

摘要

The distribution of elements in sediment cores from Lake Baikal reflects the conditions of sediment formation, and thus can be used for palaeoclimatic reconstructions. The ability to identify cyclicity in sedimentation depends on analytical methods, especially the ability to determine the speciation of elements in sediments. Application of autoradiography in combination with SR-XFA, EMPA, SEM, and TEM provides new information on micro- and nanoscale particles, crystals, and layers in the sediments. A detailed study of elemental distributions in Lake Baikal (St 8, 11) sediment cores containing U-bearing phosphates was conducted using activation autoradiography (P, U) and SR-XFA. Results of this approach showed that phosphate formations characterized by anomalous concentrations of P, U, As, Fe, Ca, Sr that should be considered in interpretations of geochemical data.