Estudos de mineralogia, isótopos estáveis (δ 18 O e δ 34 S) e geocronologia 40 Ar- 39 Ar sobre a carapaça hidrotermal do depósito de W-Sn Igarapé Manteiga, Rondônia

Nascimento, Thais Marcela Fernandes do; Souza, Valmir da Silva

doi:10.1590/2317-4889201720170068

Thais Marcela Fernandes do Nascimento

Geosciences Postgraduate Program, Universidade Federal do Amazonas - UFAM, Manaus (AM), Brazil. E-mail: thais.marcela@gmail.com

Valmir da Silva Souza ^**Corresponding author

Geosciences Postgraduate Program, Universidade Federal do Amazonas - UFAM, Manaus (AM), Brazil. E-mail: thais.marcela@gmail.com

Geosciences Institute, Universidade de Brasília - IG-UnB, Brasília (DF), Brazil. E-mail: valmirsouzaunb@gmail.com

*Corresponding author

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Figure 1:
Location of the Rondônia Tin Province. (A) Regional geological map and location of the Igarapé Manteiga W-Sn deposit (modified from CPRM 2007CPRM. 2007. Geologia e recursos minerais do Estado de Rondônia: Sistema de Informações Geográficas - SIG. Texto Explicativo do Mapa Geológico e de Recursos Minerais do Estado de Rondônia - Escala 1:1.000.000. - Porto Velho: CPRM. 153p., CD-ROM.); (B) Simplified geological map of the area around the Igarapé Manteiga W-Sn deposit (modified from Nascimento 2010Nascimento T.M.F. 2010. Depósito W-Sn Igarapé Manteiga: geologia e metalogênese. Dissertação de Mestrado, Programa de Pós-graduação em Geociências, Universidade Federal do Amazonas, Manaus, 93p.); (C) Geological E-W cross section of the open pit mine area of the Igarapé Manteiga deposit. The vertical scale is exaggerated (compiled from METALMIG 2008METALMIG 2008. Projeto Igarapé Manteiga: Avaliação e Recomendações. Relatório técnico interno, 47p. e anexos (mapas). ).

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Figure 2:
(A) Open-pit mine area developed in the apex-zone of the Igarapé Manteiga granitic stock; (B) Macroscopic textural arrangement of the mica-topaz-quartz greisen; (C) Quantitative classification of the Igarapé Manteiga greisen, applying the diagram proposed by Kühne et al. (1972, in Stemprok 1987Stemprok M. 1987. Greisenization (a review). Geologische Rundschau, 76(1):169-175.); (D) Microtexture of topaz-mica-quartz greisen (NX = crossed nicols); (E) Microtexture of quartz-topaz-mica greisen with wolframite and cassiterite disseminated crystals (N// = parallel nicols); (F) Wolframite large crystals developed in greisen. Observe the truncate and irregular geological contacts of the breccia and vein.

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Figure 3:
(A) Asymmetrical crustification texture in veins, with crusts of Li-micas, quartz and topaz, with some contributions of fluorite, siderite, ore- and sulfide minerals; (B) Comb structure in veins, mainly formed by growth quartz, topaz and mica crystals from fissure walls towards the center; (C); Thicker vein with central part filled by ore- and sulfide minerals associated to euhedral Li-micas aggregates; (D) Macroscopic textural arrangement of the polymictic breccia containing ore-mineral (wolframite) fragments.

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Figure 4:
Photomicrograph of sulfide-mineral and wolframite-cassiterite assemblage. (A) Chalcopyrite and galena occupying interstices or filling micro-fractures in sphalerite; (B) isometric pyrite (I) partially replaced by orthorhombic marcasite; (C) Bismuthinite, molybdenite and pyrite II aggregates forming fillets encrusted on the borders of preterit sulfide-minerals and filling fissures; (D) Wolframite-cassiterite aggregate in mica-topaz-quartz greisen (N// = parallel nicols); (E) BSE image of wolframite-cassiterite aggregate; (F) BSE image of xenotime micro-inclusion in wolframite. The symbols are bi = bismuthinite, cpy = chalcopyrite, gl = galena, mo = molybdenite, mr = marcasite, py = pyrite, sph = sphalerite, cs = cassiterite and wf = wolframite.

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Figure 5:
Atomic correlation diagrams (apfu) applied to wolframite crystals. (A) W vs Fe vs Mn triangular diagram; (B) W⁶⁺ vs Nb⁵⁺ + Ta⁵⁺; (C) Fe³⁺ vs Nb⁵⁺ + Ta⁵⁺.

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Figure 6:
Atomic correlation diagrams applied to cassiterite crystals. (A) Sn versus Fe + Ti; (B) Sn versus Nb+Ta; (C) Fe versus W+Mn+ Ti; (D) Sn+ Ti versus W+Mn+Fe.

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Figure 7:
Composition triangular diagram plotted in terms of (Na,Ta)-(Fe,Mn)-(Sn,Ti) for cassiterite (Neiva 2008Neiva A.M.R. 2008. Geochemistry of cassiterite and wolframite from tin and tungsten quartz veins in Portugal. Ore Geology Reviews, 33(3-4):221-238.).

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Figure 8:
Triangular diagram classification for mica in terms of Li versus Al^VI+Ti versus Fe+Mn+Mg (based on Stone et al. 1988Stone M., Exley C.S., George M.C. 1988. Compositions of trioctahedral micas in the Cornubian batholith. Mineralogical Magazine, 52:175-192.).

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Figure 9:
⁴⁰Ar-³⁹Ar age spectra for Li-Fe zinnwaldite crystals from quartz-topaz-mica greisen of the Igarapé Manteiga W-Sn deposit. (A) Plateau age calculated (988 Ma) and marked with dotted line; (B) Ca/K and Cl/K ratio measurements.

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Figure 10:
Schematic sequence of the crystallization of the hydrothermal mineral assemblage in the greisen and vein.

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Table 1:
Available geochronological data for the age of the mineralization in the Rondônia Tin Province.

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Table 2:
Electron microprobe data on the chemical composition of the wolframite and cassiterite. Oxides in wt.% and element in atoms per formula unit (apfu). Cation formula calculated on four atoms of oxygen for wolframite and on two atoms of oxygen for cassiterite.

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Table 3:
Electron microprobe data on the chemical composition of the Li-Fe zinnwaldite. Li₂O and H₂O calculations after Tindle and Webb (1990Tindle A.G., & Webb P.C. 1990. Estimation of lithium contents in trioctahedral micas using microprobe data; application to micas from granitic rocks. European Journal of Mineralogy, 2(5):595-610.).

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Table 4:
Data on the stable isotopes (δ¹⁸O and δ³⁴S) with regard to the wolframite, cassiterite, quartz and some sulfide minerals from greisen and veins. Observe the calculated values for the crystallization temperature ranges for the respective mineral pairs.

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Table 5:
⁴⁰Ar-³⁹Ar data for Fe-Li zinnwaldite from quartz-topaz-mica greisens (D-647/IG-01 sample).

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(1)

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(2)

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(3)

Sn-W deposit	Regional unit	Method	Mineral	Rock type	Age (Ma)	References
Santa Bárbara	Rondônia Intrusive Suite (995-956 Ma)	Ar-Ar	zinnwaldite zinnwaldite zinnwaldite muscovite	syenogranite albite granite bedded greisen mica vein	990 ± 5 985 ± 4 959 ± 4 987 ± 1.9	Bettencourt et al. (2005bBettencourt J.S., Sparrenberger I., Leite Jr. W.B., Payolla B.L., Onoe A.T., Tosdal R. M. 2005b. 40Ar/39Ar step heating laser system dating of zinnwaldite and muscovite from tin deposits of the Rondônia Tin Province, Brazil: evidence for multiple mineralization episodes. In: Io Simpósio Brasileiro de Metalogênese, MME/SBG/SEG, Gramado, CD-ROM.)
Santa Bárbara		K-Ar	zinnwaldite	greisen	961± 17	Leite Jr. et al. (2001Leite Jr. W.B., Payolla B.L., Betttencourt J.S., Tassinari C.C.G. 2001. New K-Ar ages of the primary tin mineralization in the Rondônia Tin Province, Brazil. In: III South American Symposium on Isotope Geology (SSAGI), Pucon-Chile, CD-ROM, 5: 484-487.)
Bom Futuro		Ar-Ar	zinnwaldite zinnwaldite	pegmatite quartz vein	994 ± 3 993 ± 3	Bettencourt et al. (2005bBettencourt J.S., Sparrenberger I., Leite Jr. W.B., Payolla B.L., Onoe A.T., Tosdal R. M. 2005b. 40Ar/39Ar step heating laser system dating of zinnwaldite and muscovite from tin deposits of the Rondônia Tin Province, Brazil: evidence for multiple mineralization episodes. In: Io Simpósio Brasileiro de Metalogênese, MME/SBG/SEG, Gramado, CD-ROM.)
		K-Ar	zinnwaldite	quartz vein	969 ± 27	Leite Jr. et al. (2001Leite Jr. W.B., Payolla B.L., Betttencourt J.S., Tassinari C.C.G. 2001. New K-Ar ages of the primary tin mineralization in the Rondônia Tin Province, Brazil. In: III South American Symposium on Isotope Geology (SSAGI), Pucon-Chile, CD-ROM, 5: 484-487.)
		U-Th-Pb	monazite	greisen	997 ± 48	Souza et al. (2005Souza V.S., Teixeira L.M., Botelho N.F. 2005. Datação U-Th-Pb de monazita hidrotermal e sua aplicação na geocronologia da mineralização de estanho em zonas de greisen do sistema granítico Palanqueta, depósito de estanho do Bom Futuro (RO). Revista Brasileira de Geociências, 35(1):43-48.)
Igarapé Manteiga		Ar-Ar	zinnwaldite	mica greisen	988 ± 5	This paper
Oriente Novo	Santa Clara Intrusive Suite (1082-1074 Ma)	K-Ar	zinnwaldite zinnwaldite zinnwaldite	greisen greisen quartz vein	1006 ± 17 981 ± 35 993 ± 16	Leite Jr. et al. (2001Leite Jr. W.B., Payolla B.L., Betttencourt J.S., Tassinari C.C.G. 2001. New K-Ar ages of the primary tin mineralization in the Rondônia Tin Province, Brazil. In: III South American Symposium on Isotope Geology (SSAGI), Pucon-Chile, CD-ROM, 5: 484-487.)
Rio Branco		K-Ar	zinnwaldite	greisen	976 ± 30
Potosi		Ar-Ar	muscovite	mica greisen	1053 ± 3	Bettencourt et al. (2005bBettencourt J.S., Sparrenberger I., Leite Jr. W.B., Payolla B.L., Onoe A.T., Tosdal R. M. 2005b. 40Ar/39Ar step heating laser system dating of zinnwaldite and muscovite from tin deposits of the Rondônia Tin Province, Brazil: evidence for multiple mineralization episodes. In: Io Simpósio Brasileiro de Metalogênese, MME/SBG/SEG, Gramado, CD-ROM.)
Oriente Novo		K-Ar	biotite	greisen	993 ± 40	Priem et al. (1971Priem H.N.A., Boelrijk N.A.I.M., Hebeda E.H., Verdurmen E.A.Th., Verschure R.H., Bon E.H. 1971. Granitic complexes and associated tin mineralizations of “Grenville” age in Rondônia, Western Brazil. Geological Society of America Bulletin, 82:1095-1102.)
Liberdade	São Lourenço-Caripunas Intrusive Suite (1314-1309 Ma)	Ar-Ar	muscovite	mica greisen	1308 ± 5	Santos Jr. (2015Santos Jr., P.S.M. 2015. Metalogênese do depósito estanífero Liberdade, Campo Novo de Rondônia - RO. Dissertação de Mestrado, Instituto de Geociências, Universidade de Brasília, no 345, 87p.)

wolframite
Spots	1	2	3	4	5	6	7	8	9	10	11	12
WO₃	75.04	73.97	73.95	74.88	74.71	74.57	74.36	75.40	74.99	75.80	75.79	76.14
SnO₂	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.01	0.00	0.00	0.00	0.00
TiO₂	0.00	0.03	0.00	0.01	0.00	0.00	0.00	0.06	0.01	0.00	0.01	0.02
CaO	0.01	0.00	0.02	0.01	0.00	0.00	0.27	0.02	0.00	0.00	0.00	0.02
Nb₂O₃	0.73	0.54	0.75	0.74	0.96	0.61	1.01	0.81	0.59	0.68	0.76	0.51
Ta₂O₃	0.36	0.20	0.36	0.38	0.40	0.31	0.17	0.22	0.20	0.23	0.18	0.18
FeO_(tot.)	15.61	16.77	15.51	15.64	16.23	14.53	15.73	15.65	15.51	15.62	15.17	15.18
MnO	9.11	7.57	9.07	8.95	8.40	9.87	8.76	8.80	8.89	8.85	8.87	8.99
Total (wt.%)	100.86	99.08	99.66	100.61	100.70	99.89	100.30	100.97	100.19	101.18	100.78	101.04
W	0.970	0.974	0.967	0.970	0.966	0.974	0.964	0.973	0.976	0.977	0.980	0.983
Sn	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000
Ti	0.000	0.001	0.000	0.001	0.000	0.000	0.000	0.002	0.001	0.000	0.001	0.001
Ca	0.001	0.000	0.001	0.001	0.000	0.000	0.015	0.001	0.000	0.000	0.000	0.001
Nb	0.016	0.012	0.017	0.017	0.022	0.014	0.023	0.018	0.013	0.015	0.017	0.012
Ta	0.005	0.003	0.005	0.005	0.005	0.004	0.002	0.003	0.003	0.003	0.003	0.003
Fe²⁺calc.	0.621	0.686	0.622	0.624	0.644	0.586	0.622	0.624	0.628	0.627	0.614	0.616
Fe³⁺calc.	0.030	0.026	0.033	0.030	0.034	0.026	0.036	0.027	0.024	0.023	0.020	0.017
Mn	0.385	0.326	0.388	0.379	0.355	0.421	0.371	0.371	0.378	0.373	0.375	0.380
Total (apfu)	2.028	2.028	2.033	2.027	2.026	2.025	2.033	2.019	2.023	2.018	2.010	2.012
wolframite
Spots	13	14	15	16	17	18	19	20	21	22	23
WO₃	75.81	76.09	75.79	75.80	75.42	75.98	75.68	75.63	75.07	75.35	75.56
SnO₂	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
TiO₂	0.00	0.01	0.00	0.00	0.02	0.00	0.00	0.01	0.00	0.01	0.00
CaO	0.02	0.01	0.00	0.00	0.02	0.00	0.00	0.00	0.00	0.00	0.00
Nb₂O₃	0.71	0.72	0.74	0.76	0.83	0.77	0.70	0.78	0.60	0.82	0.70
Ta₂O₃	0.33	0.27	0.26	0.24	0.21	0.22	0.27	0.23	0.28	0.38	0.25
FeO_(tot.)	15.51	15.22	15.34	15.30	15.21	15.40	15.37	15.36	15.58	15.27	15.45
MnO	8.92	8.83	9.06	9.08	8.91	8.94	9.03	9.00	8.95	8.89	9.11
Total (wt.%)	101.30	101.15	101.19	101.18	100.60	101.31	101.05	101.01	100.48	100.72	101.07
W	0.975	0.981	0.977	0.977	0.977	0.978	0.976	0.976	0.974	0.975	0.975
Sn	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000
Ti	0.000	0.001	0.000	0.000	0.001	0.000	0.001	0.000	0.000	0.000	0.000
Ca	0.001	0.001	0.000	0.000	0.001	0.000	0.000	0.000	0.000	0.001	0.000
Nb	0.016	0.016	0.017	0.017	0.019	0.017	0.016	0.018	0.014	0.019	0.016
Ta	0.005	0.004	0.004	0.003	0.003	0.003	0.004	0.003	0.004	0.005	0.003
Fe²⁺calc.	0.618	0.614	0.614	0.613	0.612	0.617	0.616	0.616	0.627	0.613	0.618
Fe³⁺calc.	0.025	0.019	0.023	0.023	0.023	0.022	0.024	0.024	0.026	0.025	0.025
Mn	0.379	0.372	0.382	0.383	0.377	0.376	0.381	0.380	0.380	0.376	0.384
Total (apfu)	2.019	2.008	2.017	2.016	2.013	2.013	2.018	2.017	2.025	2.014	2.021
cassiterite
Spots	1	2	3	4	5	6	7	8	9	10	11	12
SnO₂	91.18	91.28	90.85	91.61	92.53	91.20	92.57	92.67	94.24	93.72	94.49	95.30
TiO₂	0.24	0.39	0.50	0.63	0.66	0.53	0.73	0.40	0.38	0.65	0.62	0.76
Nb₂O₃	2.09	0.99	1.02	0.75	0.87	0.97	0.87	0.93	0.74	0.60	0.59	0.33
Ta₂O₃	1.70	4.50	4.27	3.73	3.63	4.32	3.41	3.47	2.92	2.48	2.30	1.38
FeO_(tot.)	2.52	1.43	1.38	1.27	1.11	1.20	1.07	1.08	0.89	1.00	1.07	0.66
WO₃	1.25	0.25	0.28	0.87	0.29	0.24	0.16	0.14	0.08	0.42	0.62	0.68
MnO	0.21	0.01	0.07	0.09	0.06	0.02	0.04	0.00	0.00	0.02	0.13	0.05
UO₂	0.00	0.03	0.00	0.03	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Total (mol%)	99.19	98.88	98.37	98.98	99.15	98.48	98.85	98.69	99.25	98.89	99.82	99.16
Sn	0.911	0.922	0.920	0.929	0.929	0.923	0.931	0.937	0.947	0.943	0.942	0.955
Ti	0.005	0.007	0.010	0.012	0.012	0.010	0.014	0.007	0.007	0.012	0.012	0.014
Nb	0.024	0.011	0.012	0.009	0.010	0.011	0.010	0.011	0.008	0.007	0.007	0.004
Ta	0.012	0.031	0.030	0.026	0.025	0.030	0.023	0.024	0.020	0.017	0.016	0.009
Fe	0.053	0.030	0.030	0.027	0.023	0.025	0.023	0.023	0.019	0.021	0.022	0.014
W	0.008	0.002	0.002	0.001	0.002	0.002	0.001	0.001	0.001	0.003	0.004	0.004
Mn	0.004	0.000	0.002	0.002	0.001	0.001	0.001	0.000	0.000	0.000	0.003	0.001
U	0.000	0.001	0.000	0.001	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000
Total (apfu)	1.017	1.004	1.006	1.007	1.003	1.002	1.003	1.002	1.002	1.003	1.006	1.001
cassiterite
Spots	13	14	15	16	17	18	19	20	21	22	23
SnO₂	95.97	95.13	95.48	95.48	98.25	98.14	97.94	97.73	95.36	97.93	97.46
TiO₂	0.70	1.23	1.23	0.80	0.12	0.16	0.05	0.11	0.49	0.05	0.07
Nb₂O₃	0.29	0.27	0.27	0.40	0.03	0.00	0.04	0.13	0.41	0.01	0.41
Ta₂O₃	1.38	1.11	1.08	1.36	0.07	0.04	0.03	0.23	1.52	0.01	0.12
FeO_(tot.)	0.55	0.63	0.68	0.86	0.30	0.26	0.32	0.41	0.77	0.44	0.42
WO₃	0.20	0.43	0.40	0.08	0.00	0.00	0.00	0.02	0.70	0.60	1.12
MnO	0.00	0.03	0.00	0.03	0.06	0.03	0.01	0.00	0.16	0.06	0.09
UO₂	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.01	0.00	0.02
Total (mol%)	99.09	98.83	99.14	99.01	98.83	98.63	98.39	98.63	99.42	99.10	99.69
Sn	0.963	0.952	0.953	0.957	0.993	0.993	0.994	0.989	0.955	0.988	0.975
Ti	0.013	0.023	0.023	0.015	0.002	0.003	0.001	0.002	0.009	0.001	0.001
Nb	0.003	0.003	0.003	0.005	0.000	0.000	0.000	0.001	0.005	0.000	0.005
Ta	0.009	0.008	0.007	0.009	0.001	0.000	0.000	0.002	0.010	0.000	0.001
Fe	0.012	0.013	0.014	0.018	0.006	0.006	0.007	0.009	0.016	0.009	0.009
W	0.001	0.003	0.003	0.001	0.000	0.000	0.000	0.000	0.005	0.004	0.007
Mn	0.000	0.001	0.000	0.001	0.001	0.001	0.000	0.000	0.003	0.001	0.002
U	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000
Total (apfu)	1.001	1.003	1.003	1.006	1.003	1.003	1.002	1.003	1.003	1.003	1.000

Spots	1	2	3	4	5	6	7	8	9	10	11	12
SiO₂	46.33	44.14	46.96	46.75	47.66	46.36	46.77	47.74	47.29	47.69	47.92	46.53
TiO₂	0.11	-	0.19	0.08	0.10	0.07	0.09	-	0.26	-	0.40	0.33
Al₂O₃	23.91	24.78	25.51	25.24	26.10	25.10	24.39	25.00	25.06	25.18	25.54	25.69
FeO	11.08	9.76	6.36	7.66	5.90	6.28	8.03	6.55	7.33	6.62	6.38	6.91
MnO	0.11	0.44	0.28	0.56	0.25	0.51	0.32	0.2	0.29	0.17	0.18	0.26
MgO	0.63	0.83	2.23	2.34	1.76	2.55	2.02	2.24	2.05	2.49	1.90	2.52
CaO	0.023	0.01	0.007	0.045	0.029	0.013	0.106	0	0.05	0	0.006	0
Na₂O	0.03	0.12	0.239	0.26	0.25	0.19	0.17	0.17	0.32	0.18	0.166	0.135
K₂O	10.45	10.53	10.59	9.96	10.51	10.05	9.87	10.64	10.23	10.46	10.69	10.67
F	5.198	5.004	5.895	5.605	5.361	5.724	5.71	6.094	6.379	6.229	6.091	6.208
Li₂O*	3.75	3.12	3.93	3.87	4.13	3.76	3.87	4.15	4.02	4.14	4.20	3.80
H₂O*	1.89	1.85	1.65	1.79	1.95	1.67	1.69	1.58	1.44	1.53	1.62	1.51
Subtotal	103.54	100.62	103.86	104.20	104.03	102.33	103.07	104.39	104.74	104.73	105.14	104.61
O = F. Cl	2.19	2.11	2.48	2.36	2.26	2.41	2.40	2.57	2.69	2.62	2.56	2.61
Total wt.%	101.35	98.52	101.38	101.84	101.77	99.92	100.67	101.82	102.05	102.11	102.57	101.99
Si	6.38	6.26	6.33	6.30	6.36	6.33	6.38	6.40	6.35	6.37	6.37	6.26
Al iv	1.61	1.73	1.66	1.69	1.63	1.66	1.61	1.59	1.64	1.62	1.62	1.73
Al vi	2.26	2.41	2.39	2.32	2.47	2.38	2.30	2.35	2.32	2.34	2.38	2.34
Ti	0.01	-	0.02	-	0.01	-	0.01	-	0.02	-	0.04	0.03
Fe	1.27	1.15	0.71	0.86	0.65	0.71	0.91	0.73	0.82	0.74	0.71	0.77
Mn	0.01	0.05	0.03	0.06	0.02	0.05	0.03	0.02	0.03	0.02	0.02	0.03
Mg	0.13	0.17	0.44	0.47	0.35	0.52	0.41	0.45	0.41	0.49	0.37	0.50
Li*	2.07	1.77	2.13	2.09	2.21	2.06	2.12	2.23	2.17	2.22	2.24	2.06
Ca	-	-	-	-	-	-	0.01	-	-	-	-	-
Na	-	0.03	0.06	0.06	0.06	0.05	0.04	0.04	0.08	0.04	0.04	0.03
K	1.83	1.90	1.82	1.71	1.79	1.75	1.71	1.82	1.75	1.78	1.81	1.83
OH*	1.73	1.75	1.48	1.60	1.73	1.52	1.53	1.41	1.28	1.36	1.43	1.35
F	2.26	2.24	2.51	2.39	2.26	2.47	2.46	2.58	2.71	2.63	2.56	2.64
Cl	-	-	-	-	-	-	-	-	-	-	-	-
Total (apfu)	19.624	19.523	19.625	19.617	19.606	19.565	19.589	19.671	19.638	19.666	19.635	19.625

Mineral	δ¹⁸ O (‰)	δ³⁴ S (‰)	Mineral pairs	Temperature range (°C)
quartz	9.1	-
quartz	9.7	-
wolframite	0.6	-	wolframite + quartz	309 - 354
wolframite	0.9	-	wolframite + quartz	309 - 354
cassiterite	1.6	-	cassiterite + quartz	422 - 480
cassiterite	1.8	-	cassiterite + quartz	422 - 480
pyrite	-	2.35
pyrite	-	2.38
pyrite	-	2.67
chalcopyrite	-	1.31	chalcopyrite + pyrite	355 - 390
chalcopyrite	-	1.36
chalcopyrite	-	1.53
sphalerite	-	1.44	sphalerite + pyrite	416 - 471
sphalerite	-	1.58
sphalerite	-	1.69
molybdenite	-	0.52	molybdenite + pyrite	229 - 272
molybdenite	-	0.63	molybdenite + pyrite	229 - 272

Power	³⁶ Ar/⁴⁰ Ar	³⁹ Ar/⁴⁰ Ar	r	Ca/K	%⁴⁰ Atm	%³⁹ Ar	⁴⁰ Ar*/³⁹ K	Age (Ma)
0.50	0.001131	0.016468	0.003	0.082	33.40	0.20	40.43 ± 2.52	868.7 ± 42.9
0.75	0.000230	0.019587	0.001	0.067	6.80	0.65	47.58 ± 0.92	986.7 ± 14.7
1.00	0.000045	0.020385	0.001	0.023	1.34	2.66	48.40 ± 0.60	999.7 ± 9.6
1.25	0.000005	0.020665	0.000	0.010	0.16	6.39	48.31 ± 0.45	998.4 ± 7.2
< 1.50	0.000008	0.020877	0.000	0.044	0.22	9.31	47.79 ± 0.49	990.1 ± 7.8
< 1.75	0.000007	0.020808	0.000	0.041	0.22	10.72	47.95 ± 0.55	992.6 ± 8.7
< 2.00	0.000002	0.020802	0.000	0.002	0.05	8.52	48.05 ± 0.59	994.2 ± 9.5
< 2.25	0.000009	0.020809	0.000	0.034	0.26	9.76	47.93 ± 0.47	992.3 ± 7.5
< 2.50	0.000012	0.020749	0.000	0.024	0.37	6.44	48.02 ± 0.55	993.7 ± 8.7
< 3.00	0.000010	0.021032	0.000	0.039	0.31	10.41	47.40 ± 0.50	983.8 ± 8.0
< 3.50	0.000008	0.020950	0.001	0.096	0.24	13.34	47.62 ± 1.06	987.3 ± 16.9
< 4.00	0.000001	0.020954	-0.000	0.021	0.02	1.88	47.72 ± 0.61	988.9 ± 9.8
< 5.00	-0.000000	0.021008	-0.000	0.047	-0.01	0.80	47.60 ± 0.88	987.1 ± 14.1
< 7.00	0.000032	0.020894	0.003	0.045	0.94	18.93	47.41 ± 0.83	984.0 ± 13.3

[1] *Corresponding author

Brasil

Brasil

Estudos de mineralogia, isótopos estáveis (δ ¹⁸ O e δ ³⁴ S) e geocronologia ⁴⁰ Ar- ³⁹ Ar sobre a carapaça hidrotermal do depósito de W-Sn Igarapé Manteiga, Rondônia

RESUMO: