Reconstruction of Holocene environmental changes in North-Western Pacific in relation to paleorecord from Shikotan Island

Results of a paleolimnological investigation of a well-dated lake sediment section from Shikotan Island (Southern Kurils) showed that from ca 8.0 to 5.8 cal ka BP a warm and humid period corresponding to middle Holocene optimum took place. Cooling thereafter corresponds to Neoglacial. A reconstructed from ca 0.9 to ca 0.58 cal ka BP warm period can correspond to a Medieval Warm Period. Cooling after 0.58 cal ka BP can be correlated with the LIA. Marine regression stages were identified at ca 6.2–5.9, 5.5– 5.1 and 1.07–0.36 cal ka BP. The general chronology of major climatic events of Holocene in the island is in accordance with the climate records from the North Pacific region. Revealed spatial differences in timing and magnitude of the Late Holocene climatic episodes (LIA, MWP) in the region needs further investigations

Effects of matrix composition and Eu³⁺ concentration on luminescence properties of phosphate glass

The effect of Li₂O and ZnO content and Eu³⁺ ion concentration in the glass composition on the decay of luminescence was investigated in phosphate glasses of composition P₂O₅—Li₂O—ZnO . The emission was excited by high-current electron beam of nanosecond duration with an electron energy of 200 eV. It was found that in the range of 0.5—3 wt.% Eu₂O₃ the decay time depends weakly on europium ion concentration. The increase of ZnO (with parallel reduction of Li₂O ) leads to a shortening the decay time of luminescence in the bands at 592 and 614 nm of 2.1 to 1.5 ms. This is due to the symmetry reduction of the Eu³⁺ ion environment. The rise of luminescence signal with duration of some microseconds in the kinetics of the luminescence peak at 614 nm was observed