Abstract
Hokutolite, plumbian barite, crystallized by the splashing of hot spring water was examined in comparison with the hokutolite crystallized in the hot spring water at Tamagawa Hot Spring in Japan. The results are as follows: 1) The hokutolite formed by the splashing contains more Pb, Sr, Ca and less Fe than the hokutolite formed in the water. The average chemical composition of the former is PbO=13.50 wt.%, SrO=0.35 wt.%, CaO=0.17 wt.%, Fe2O3 =0.11 wt.%, and that of the latter is PbO=9.66 wt.%, SrO=0.32 wt.%, CaO=0.11 wt.%, Fe2O3=0.52 wt. %. 2) The hokutolite formed by the splashing contains less sulfur crystal and Fe compound than the hokutolite formed in the water. 3) The high contents of Pb, Sr, Ca in the hokutolite formed by the splashing is supposed to be caused by the rapid cooling and concentration of the hot spring waters, which can be explained semi-quantitatively by phenomenological equations.
