HR: 0830h
AN: V51H-0370    [PDF]
TI: Probing zeolite syntheses to determine natural occurances of zeolites
AU: Chen, H
EM: fen@ms22.url.com.tw
AF: Institute of Geosciences, National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Song, S
EM: srsong@ntu.edu.tw
AF: Institute of Geosciences, National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: * Fang, J
EM: jnfang@eden.tpm.gov.tw
AF: Department of Earth Science, National Taiwan Museum, 48 Hsuchow Road, Taipei, 100 Taiwan
AB: In this study, zeolites were synthesized from different glasses to probe the occurrence of zeolites in nature. The experiments were carried out with synthetic glass systems of Na2O.Al2O3.nSiO2, CaO.Al2O3.nSiO2, xNa2O.(1-x)CaO.Al2O3.nSiO2 and xNa2O.(1-x)K2O.Al2O3.6SiO2 in alkaline solutions of NaOH, KOH, Na2CO3, NH4OH, NaOH (+) NaCl and NaOH (+) KOH at temperatures ranging from 110›J to 210›J and with autogeneous pressures in the autoclaves. Synthetic products were examined by an X-ray powder diffractometer, a scanning electron microscopy with an energy dispersive spectrometer, and an electron microprobe. The minerals synthesized included zeolites, i.e., thomsonite, gismondine, amicite, garronite, gobbinsite, analcime, phillipsite, merlinoite, chabazite and mordenite; artificial synthetic zeolites, and feldspars. Chemical analyses indicated that the composition of synthetic zeolites is profoundly influenced by the composition of the initial glasses, especially the SiO2/Al2O3 ratios and cations. On the other hand, the influence of Na+ and K+ have over the formation of zeolites in solution, other ions, such as CO32- were involved in the preventing of the formation of Ca-zeolites. Comparing the experimental results with natural occurrences suggests that thomsonite, gismondine and amicite are usually found in ultrabasic and basic rocks; garronite and gobbinsite in basic to intermediate rocks; analcime, phillipsite, and chabazite in basic to acid rocks; merlinoite in high-potassium rocks; and mordenite in acid rocks. In addition, Ca-zeolites including thomsonite, gismondine and garronite are favored in fresh water environments, and alkali zeolites including gobbinsite, phillipsite, and analcime are most abundant in saline lake and deep sea conditions.
DE: 3600 MINERALOGY AND PETROLOGY (replaces
DE: 3620 Crystal chemistry
DE: 3630 Experimental mineralogy and petrology
DE: 3665 Mineral occurrences and deposits
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting