MEVO - Lava Chemistry

Generalized petrographic summary of Mt. Erebus volcanic rocks (from Kyle et al., 1992)
Rock Type	Texture	Ol	Cpx	Kaer	Op	Fsp	Ap	Fspth	Gnd Ms
Basanite	fp(10-25)	p, x	p		p	p	p	g	p, I
Ne hawaiite	fp(1-20) or p(20-50)	p, po	r-p, po	r, po, x?	p	p	p	r-g	I, p or gl-h2c, 2o
Ne mugearite	cp(20-30)	p, po	p, po		p	p	p	g	I, p, 2o
Ne benmoreite	cp(20-50)	p, po, x	r-p		p	p	p	g	I, p or gl
Anorthoclase phonolite	cp(30-60)	p	p		p	p	p	r-g	I, p orgl-h, c
Benmoreite	mp(10-20)	p, po, x	r-p	r-p, po	p	p-x	r		t or gl, c
Phonolite	mp(3-10) orp(10-15)	r-p, x	r-g	r-ppo-co	r-p	p-x	r	g	t or h-I, p
Trachyte	mp(<5)	g-x	p		p	p			t
Abbreviations:
Texture: p-porphyritic; mp-microporphyritic; fp-finely porphyritic; cp-coarsely porphyritic;
percentage of phenocrysts to nearest 5% is given in parenthesis.
Mineralogy: Ol-olivine; Cpx-clinopyroxene; Kaer-kaersutite; Op-opaque oxides; Fsp-feldspar; Ap-apatite; Fspth-feldspathoids;
p-present (>1%); r-rare (<1%); x-xenocrystic; po-partially oxidized; co-completely oxidized; g-groundmass only.
Groundmass: I-intersertal; p-pilotaxitic; gl-glassy; h-hyalophitic; c-cryptocrystalline; t-trachytic;
2c-secondary carbonate; 2o-secondary oxidation.

Chemistry of Mt. Erebus Volcanic Bombs
Table reproduced from: Caldwell, D.A., and Kyle, P.R., 1994, Mineralogy and geochemistry of ejecta erupted from Mount Erebus, Antarctica, between 1972 and 1986, in Kyle, P.R., ed., Volcanological and Environmental Studies of Mount Erebus, Antarctica, Volume 66: Washington, D.C., American Geophysical Union, p. 147-162. Average Electron Microprobe Analyses of Matrix Glass Separated From Bombs Erupted Between 1972 and 1987 From Mount Erebus.
Year	1972/73	1975/76	1977/78	1978/79	1979/80	1981/82	1982/83	1983/84	1984/85	1985/86	1986/87
# of anal.	(13)	(13)	(14)	(13)	(12)	(12)	(10)	(14)	(13)	(9)	(10)
SiO2	55.38	55.54	55.60	55.65	55.60	55.45	55.29	55.96	55.88	55.74	55.60
Al2O3	19.02	19.03	19.45	19.49	19.33	19.39	19.23	19.59	19.53	19.37	19.41
TiO2	1.03	1.02	1.04	1.06	1.09	1.00	1.06	1.04	1.01	1.07	1.05
FeO	5.37	5.47	5.37	5.30	5.51	5.41	5.46	5.35	5.26	5.28	5.42
MnO	0.19	0.17	0.19	0.22	0.24	0.19	0.20	0.21	0.19	0.37	0.30
MgO	0..82	0.80	0.81	0.81	0.83	0.81	0.81	0.83	0.84	0.79	0.84
CaO	1.90	1.93	1.84	1.96	1.91	1.91	1.90	1.86	1.85	1.98	1.81
Na2O	9.67	9.46	9.31	9.44	9.41	9.38	9.36	9.56	9.47	9.40	9.41
K2O	5.20	5.32	5.35	5.10	5.22	5.27	5.19	5.34	5.39	5.42	5.31
Total	98.58	98.74	98.96	99.03	99.20	98.81	98.50	99.74	99.42	99.42	99.15

Chemistry of Lava Flows
Table reproduced from: Kyle, P.R., Moore, J.A., and Thirlwall, M.F., 1992, Petrologic evolution of anorthoclase phonolite lavas at Mount Erebus, Ross Island, Antarctica: Journal of Petrology, v. 33, p. 849-875. Select values from Represenative analyses of volcanic rocks from Mt. Erebus. The complete table, in Microsoft Excel format, can be downloaded.
	1	4	9	12	16	17	19	21
SiO2	43.32	44.89	50.17	55	56.57	54.28	58.91	63.51
TiO2	3.78	3.2	2.18	1.36	0.98	1.2	0.44	0.43
Al2O3	15.38	16.96	18.64	18.29	19.31	18.01	18.47	15.33
FeO*	12.08	11.23	8.04	6.59	4.95	8.46	5.89	6.15
MnO	0.22	0.23	0.22	0.27	0.23	0.29	0.26	0.21
MgO	6.77	4.21	2.51	1.64	0.99	1.57	0.37	0.14
CaO	10.66	9.28	5.73	3.34	2.75	4.4	2.19	1.44
Na2O	4.63	5.24	6.44	7.77	8.17	6.52	7.66	6.56
K2O	1.72	2.07	3.52	4.39	4.55	3.38	4.67	5.23
P2O5	1.21	1.69	1.1	0.56	0.42	0.51	0.13	0.05
LOI	0.03	-0.13	-0.01	-0.28	-0.21	0.01	0.03	0.18
Total	99.82	98.88	98.53	98.92	98.72	98.62	99.02	99.23
Major elements are given in wt. %. 1, Basanite (83435), Cape Barne; 4, Ne hawaiite (83432), Cape Barne; 9, Ne mugearite (83417), Tent Island; 12, anorthoclase phonolite (83452), Bomb Peak; 16, anorthoclase phonolite (80020), Three Sisters Cone; 17, benmoreite (83412), Inaccessible Island; 19, phonolite (83407), Inaccessible Island; 21, trachyte (82405), Bomb Peak. LOI, loss on ignition.

Mount Erebus Volcano Observatory