Earth, Planets and Space

Table 1 Representative chemical compositions of Fe–Ti oxides

From: Magnetic petrology of pumice fall deposits of the 1783 eruption of Asama volcano, Japan

No.	1	2	3	4	5	6	7
(wt.%)
SiO₂	0.31	0.44	0.30	0.43	0.43	0.00	0.00
TiO₂	9.49	13.41	13.51	11.21	8.77	42.41	42.11
FeO*	78.81	76.27	76.81	78.22	78.29	52.85	52.52
MgO	2.68	2.52	2.36	2.65	3.60	2.83	3.02
Al₂O₃	3.17	2.55	2.53	2.68	3.47	0.36	0.34
CaO	0.54	0.06	0.00	0.00	0.02	0.04	0.03
MnO	0.31	0.36	0.33	0.35	0.27	0.28	0.27
Total	95.31	95.60	95.83	95.54	94.84	98.75	98.30
Recalculated
FeO	35.76	40.11	40.44	38.06	34.44	32.77	32.18
Fe₂O₃	47.84	40.19	40.42	44.63	48.73	22.31	22.61
Total	100.10	99.62	99.88	100.01	99.72	100.99	100.56
X_usp (mol%)	27.26	38.77	36.41	32.54	25.63
X_il (mol%)						78.76	78.44

Nos. 1 and 2 are TM (Type I) of 2p. Nos. 3 and 4 are TM of 21pu. No. 5 is the TM (Type II) of symplectite. No. 6 is TH of 2p. No. 7 is TH of 21pu. FeO*: total iron as FeO. Recalculations for ferric iron contents are based on Carmichael (1967). X_usp and X_il are ulvöspinel content of TM and ilmenite content of TH, respectively

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