ASTRONOMICAL FORCING IN COSMOGENIC BE-10 VARIATION FROM EAST ANTARCTICA COAST

Cosmogenic Be-10 concentrations in Antarctic ice (Vostok site), during the past 150 ka (1 ka = 1000 years) have been spectrally analyzed. Th e current interest in beryllium refers on its use as a dating tool in lake, offshore/marine, and ice-core environments, and for palaeoclimat e variation and reconstruction. The methods of fast fourier transform, maximum entropy, and power spectrum employing the Blackman-Tukey wind ow, as well as significance tests (chi(2), Kolmogorov-Smirnov, analysi s per subset, randomness test etc.) were applied. Significant and stro ngly stationary periodicities centered around 100 ka (large uncertaint y, near the record length), 40 ka, 25 ka, 19 ka, 12 ka and 5 ka were f ound, superimposed upon each other forming a network of periodic cycle s. Similar periodicities were previously reported for delta(18)O varia tion from V28-239 pacific ocean deep-sea core and other direct or prox y palaeoclimatic data. They are recognized with the well known astrono mical frequencies; the long-term variations in the geometry of the ear th's orbit and rotation as the fundamental causes of Pleistocene ice-a ges of the past 3 Ma. This astronomical forcing (referred to as the Mi lankovich theory) is for first time observed in Be-10 variation, and i nteresting observations can be made regarding the contiguity between B e-10 production-deposition rates, palaeoclimate, solar activity, earth 's orbit and rotation, sea-level changes and geomagnetic field.