STATISTICAL CHARACTERISTICS OF OSCILLATORY ZONING OF CAVE CALCITE - POPCORN FROM HUNGARY

Grey level optical variations in cave calcite and PIXE trace element data were investigated using statistical methods. Spectral analysis of grey level shows a pronounced periodicity. Fractal geometry applied to the grey level variation gives Hurst exponent of 0.65 by measured width and spectrum-power methods, indicating persistent behavior. The grey level is strongly correlated with Sr concentration. The Sr content is anti-correlated with Fe content. This means that Sr-rich zones are light and Fe-rich zones are dark. Spectral analysis of PIXE data has found that Fe distribution and Sr distribution are periodic. Other trace elements (As, Cu, Ni, Zn) do not show a periodicity. This suggest that 1) the experimental noise level for these elements is too great, or 2) their substitutions is decoupled from Fe and Sr. The zoning profiles of As, Cu, Ni and Zn can be described in term of self-affine fractals only at length scales smaller than 1mm, where they have Hurst exponents in range 0.15 - 0.36. Profiles of Fe and Sr can be described in term of self-affine fractals at any length scales and they have persistent behavior (H>0.5) at length scales smaller than 0.1 mm.