CONDENSATE COMPOSITIONS AND NATIVE METALS IN SUBLIMATES OF HIGH-TEMPERATURE GAS STREAMS OF KUDRYAVYI VOLCANO, ITURUP ISLAND, KURIL ISLANDS

Unique stationary gas streams with temperatures of 500-940 degrees C w ere studied. The oxidized forms H2O and CO2 were found to dominate in the gas mixture. Gas analysis (CO/CO2 and SO2/H-2/H2S) as well as dire ct measurements indicate that f(O-2) is close to the NNO buffer. The r esults of condensate analysis for 68 elements are presented. The conce ntration of iodine is higher than that of bromine. Sublimates deposite d inside air-cooled quartz tubes in the 930-680 and 705-400 degrees C temperature ranges were examined. In addition to common rock-forming m inerals and sulfides, the native metals Al, Si, Ti, Fe, and Pt were de tected in the tubes. A model of Al formation and of the preservation o f the metal as a result of the disproportionation of AlCl0 in the oxyg en-free environment of the salt melt is proposed. Products of the eute ctic solidification of an Al + Si alloy were also found, and this indi cates that at the time of the sample formation, the metals were in the liquid phase. The formation of native metals like Al, Si, or Ti does not necessarily involve any special reduced fluid because they are for med from a normal magmatic gas consisting primarily of steam (95% H2O) .