The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

Kempf, Elias D.; Hermann, Jörg; Reusser, Eric; Baumgartner, Lukas P.; Lanari, Pierre

doi:10.1186/s00015-020-00368-0

Swiss Journal of Geosciences

Table 6 Major and minor element composition of accessory phases

From: The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

Sample	FA	Ol26		14					Ol26	FA				FA	FA	Ol26
Mineral	Grt	Grt		Ilm	Ilm	Ilm	Ilm		Prv	Bc	Bc	Bc	Bc	Serp	Cpx	Cpx	Cpx
wt%	incl in Cr–Mt	in vein		incl in Ti-ch	incl in Ti-ch	Large ilm	Large ilm
SiO₂	35.67	35.90		0.10	0.07	0.01	0.04		0.92	b.d.	b.d.	b.d.	b.d.	41.74	55.64	55.44	55.15
TiO₂	0.56	0.06		58.45	58.13	56.33	57.93		53.87	b.d.	0.01	0.01	b.d.	b.d.	b.d.	b.d.	b.d.
Al₂O₃	0.16	0.09		b.d.	b.d.	0.02	0.01		b.d.	0.02	b.d.	0.01	b.d.	b.d.	0.01	b.d.	b.d.
Cr₂O₃	12.15	0.03		0.01	0.01	0.02	0.01		b.d.	0.04	0.02	0.04	0.02	0.07	0.01	b.d.	b.d.
Fe₂O₃	18.26	30.02		6.40	5.89	6.57	5.17		–	–	–	–	–	–	–	–	–
FeO	0.48	b.d.		9.16	9.95	18.64	13.23		0.67	4.03	4.40	5.92	6.07	2.29	0.50	0.45	0.36
MnO	0.29	b.d.		5.06	5.13	3.08	3.36		0.11	0.84	0.70	1.09	0.94	0.16	0.03	0.04	0.03
NiO	b.d.	b.d.		0.08	0.06	0.03	0.02		0.01	0.25	0.21	0.24	0.25	0.19	0.04	0.05	0.02
MgO	b.d.	0.04		21.50	20.84	16.17	19.87		0.31	64.80	64.67	62.71	62.70	42.80	18.08	17.79	18.04
CaO	33.08	34.59		0.01	0.01	0.02	0.01		41.31	0.08	0.07	0.07	0.08	0.06	26.33	26.52	26.65
H₂O	–	–		-.	–	–	–		–	30.30	30.27	29.89	29.88	12.81	–	–	-.
Total	100.65	100.73		100.76	100.10	100.90	99.67		97.26	100.38	100.34	99.97	99.96	100.11	100.64	100.29	100.24
Si	2.981	2.998		0.002	0.002	< 0.001	0.001		0.021	–	–	–	–	1.953	2.000	2.001	1.993
Ti	0.035	0.004		0.946	0.950	0.944	0.957		0.932	–	<0.001	< 0.001	–	–	–	–	–
Al	0.016	0.009		–	–	0.001	<0.001		–	<0.001	–	<0.001	–	–	< 0.001	–	–
Cr	0.803	0.002		< 0.001	< 0.001	< 0.001	< 0.001		–	<0.001	< 0.001	< 0.001	< 0.001	0.003	< 0.001	–	–
Fe²⁺	0.034	–		0.165	0.181	0.348	0.243		–	0.033	0.036	0.050	0.051	0.090	0.015	0.014	0.011
Fe³⁺	1.148	1.887		0.104	0.096	0.110	0.085		0.013	–	–	–	–	–	–	–	–
Mn	0.021	–		0.092	0.094	0.058	0.063		0.002	0.007	0.006	0.009	0.008	0.007	0.001	0.001	0.001
Ni	–	–		0.001	0.001	0.001	<0.001		< 0.001	0.002	0.002	0.002	0.002	0.007	0.001	0.001	0.001
Mg	–	0.006		0.690	0.675	0.537	0.650		0.011	0.956	0.955	0.938	0.938	2.985	0.968	0.957	0.971
Ca	2.962	3.095		< 0.001	< 0.001	< 0.001	<0.001		1.018	0.001	0.001	0.001	0.001	0.003	1.014	1.025	1.032
H	–	–		–	–	–	–		–	2.000	2.000	2.000	2.000	4.000	–	–	–
Grossular	< 0.001	0.083	Hematite	0.052	0.048	0.055	0.043	Mg#	–	95.7	95.6	93.9	93.9	96.7	98.3	98.3	98.8
Spessartite	0.007	< 0.001	Ilmenite	0.164	0.181	0.348	0.243	Cat#	2.000	0.999	1.000	1.000	1.000	5.046	4.000	3.999	4.007
Andradite	0.577	0.913	Geikilite	0.689	0.675	0.538	0.651
Uvarovite	0.404	0.001	Mn-Ilmenite	0.092	0.094	0.058	0.063

Grt Garnet, Ilm Ilmenite, Prv Perovskite, Bc Brucite, Serp Lizardite/Chrysotile, Cpx clinopyroxene (diopside), b.d. below detection limit
Grt is normalized to 7 cations and 24 charges, Ilm on 2 cations and 6 charges, Prv on 3 oxygens, Bc on 2 oxygens, Serp on 9 oxygens and Cpx on 6 oxygens
Cat# = number of cations
Mg# = (Mg/(Mg + Fe + Ni + Mn))*100
– Not analysed or calculated

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