Author:
Pekov I. V.,Zubkova N. V.,Agakhanov A. A.,Turchkova A. G.,Zhitova E. S.,Pushcharovskii D. Yu.
Abstract
Abstract
A new, unusual, Fe-free, and As5+-rich variety of chladniite, a rare phosphate of the fillowite group, was found in exhalations of the active Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia. It belongs to the high-temperature (500–750°С) paragenesis with calciojohillerite, fluorapatite, metathénardite, diopside, enstatite, forsterite, and hematite. This genetic type is novel for fillowite-group minerals. The crystal structure of Tolbachik chladniite is determined, R1 = 4.32%. It is trigonal, R–3, a = 14.9831(2) Å, c = 42.8050(7) Å, and V = 8322.1(3) Å3. The structural formula is M13(Na0.56$$\square $$0.44)$$_{2}^{{M21}}$$(Na0.81Ca0.19)$$_{2}^{{}}$$$$_{{}}^{{M31}}$$(Na0.97$$\square $$0.03)$$_{6}^{{M12}}$$(Ca0.64Na0.36)$$_{6}^{{M1}}$$MnM2(Mg0.54Ca0.46)M3-9Mg30M10(Mg0.94Ca0.06)$$_{6}^{{M11}}$$Mg6(P33.53As2.47)O144 (Z = 3). The crystal chemical features of chladniite and their correlation with formation settings are discussed for all chladniite findings known in meteorites and terrestrial objects of different genetic types.
Subject
General Earth and Planetary Sciences,Earth and Planetary Sciences (miscellaneous)
Reference16 articles.
1. A. Livingstone, Mineral. Mag. 43, 833–836 (1980).
2. T. Araki and P. B. Moore, Am. Mineral. 66, 827–842 (1981).
3. T. J. McCoy, I. M. Steele, K. Keil, B. F. Leonard, and M. Endreb, Am. Mineral. 79, 375–380 (1994).
4. I. M. Steele, in Proc. 25th Lunar and Planetary Science Conf. (LPSC XXV) (Houston, 1994), pp. 1337–1338.
5. E. J. Olsen and I. M. Steele, Meteorit. Planet. Sci. 32, A155–A156 (1997).