Table 1 Chemical compositions of the studied samples

From: Oxide nanolitisation-induced melt iron extraction causes viscosity jumps and enhanced explosivity in silicic magma

Oxides (wt%)	Initial	SD	Synthesised with iron content variable respect to natural rhyolite									SD	Nanocrystal-bearing
Oxides (wt%)	Natural rhyolite^a	SD	Kb-Fe-0	SD	Kb-Fe-25	SD	Kb-Fe-50	SD	Kb-Fe-75	SD	Kb-Fe-100	SD	Bulk^b	SD	Melt^c
SiO₂	75.55	0.48	77.88	0.54	77.52	0.15	76.59	0.38	75.85	0.50	74.93	0.57	75.72	0.49	77.27
TiO₂	0.26	0.05	0.29	0.04	0.26	0.05	0.28	0.05	0.27	0.05	0.27	0.05	0.26	0.05	0.13
Al₂O₃	12.14	0.20	12.94	0.20	12.85	0.19	12.51	0.18	12.70	0.19	12.40	0.17	12.32	0.13	12.34
Fe₂O₃Tot	3.35	0.17	0.08	0.03	0.83	0.05	1.68	0.11	2.35	0.12	3.19	0.11	3.34	0.14	1.03
MnO	0.10	0.04	0.07	0.05	0.08	0.05	0.07	0.05	0.07	0.05	0.07	0.05	0.08	0.04	0.10
MgO	0.11	0.02	0.13	0.02	0.12	0.03	0.11	0.03	0.13	0.02	0.11	0.03	0.09	0.03	0.09
CaO	1.73	0.10	1.50	0.08	1.50	0.07	1.47	0.09	1.46	0.08	1.43	0.09	1.79	0.09	1.77
Na₂O	4.29	0.09	4.32	0.09	4.15	0.15	4.07	0.14	4.04	0.17	3.96	0.23	4.25	0.17	4.39
K₂O	2.73	0.09	2.97	0.05	2.92	0.07	2.84	0.08	2.89	0.11	2.89	0.09	2.82	0.10	2.79
P₂O₅	0.01	0.01	0.01	0.01	0.01	0.02	0.01	0.01	0.01	0.02	0.01	0.02	0.02	0.02	0.01
Cr₂O₃	n.d.	–	0.02	0.02	0.01	0.02	0.02	0.03	0.01	0.01	0.02	0.03	0.02	0.03	–
SO₃	n.d.	–	0.02	0.02	0.02	0.02	0.02	0.03	0.02	0.02	0.01	0.02	0.03	0.02	–
Cl	n.d.	–	0.01	0.01	0.01	0.01	0.01	0.01	0.01	0.01	0.01	0.01	0.05	0.02	–
Total	100.28	–	100.24	–	100.27	–	99.69	–	99.82	–	99.31	–	100.78	–	99.93
FeO^d	n.d.	–	b.d.	–	0.29	–	0.57	–	0.86	–	1.14	–	–	–	0.46
Fe₂O₃^e	n.d.	–	n.d.	–	0.50	–	1.05	–	1.39	–	1.93	–	n.d.	–	n.d.
n =	10	–	11	–	15	–	22	–	22	–	22	–	19	–	–
Normalised values
SiO₂	75.34	–	77.69	–	77.31	–	76.83	–	75.98	–	75.45	–	75.13	–	77.32
TiO₂	0.26	–	0.29	–	0.26	–	0.28	–	0.28	–	0.28	–	0.26	–	0.13
Al₂O₃	12.11	–	12.91	–	12.81	–	12.55	–	12.72	–	12.48	–	12.23	–	12.34
Fe₂O₃T	3.34	–	0.08	–	0.83	–	1.69	–	2.36	–	3.22	–	3.31	–	1.03
MnO	0.1	–	0.07	–	0.08	–	0.07	–	0.07	–	0.07	–	0.08	–	0.10
MgO	0.11	–	0.13	–	0.12	–	0.11	–	0.13	–	0.11	–	0.08	–	0.09
CaO	1.73	–	1.50	–	1.49	–	1.48	–	1.46	–	1.44	–	1.77	–	1.78
Na₂O	4.28	–	4.31	–	4.14	–	4.08	–	4.05	–	3.99	–	4.22	–	4.39
K₂O	2.72	–	2.96	–	2.91	–	2.85	–	2.90	–	2.91	–	2.80	–	2.79
P₂O₅	0.01	–	0.01	–	0.01	–	0.01	–	0.01	–	0.01	–	0.02	–	0.01
Cr₂O₃	–	–	0.02	–	0.01	–	0.02	–	0.01	–	0.02	–	0.02	–	–
SO₃	–	–	0.02	–	0.02	–	0.02	–	0.02	–	0.01	–	0.03	–	–
Cl	–	–	0.01	–	0.01	–	0.01	–	0.01	–	0.01	–	0.05	–	–
Total	100	–	100	–	100	–	100	–	100	–	100	–	100	–	100

Data acquired by electron probe micron-analysis (EPMA) and corresponds to an average of “n” analyses.
SD standard deviation, b.d. below detection limit, n.d. not determined.
^aData from Cáceres et al.¹⁵.
^bMelt + nanocrystals by EPMA in cooling-controlled (cc) sample.
^cMelt composition from 1.12 vol.% oxide crystals in rhyolite-MELTS simulation (see “Methods”).
^dKarl-Fischer titration analyses on the post-viscosity measurements.
^eFe₂O₃ = Fe₂O₃Tot − 1.11*FeO.

Back to article page

Table 1 Chemical compositions of the studied samples

Search

Quick links