Post-collisional basalts of the Acampamento Velho Formation, Camaquã Basin, São Gabriel Terrane, southernmost Brazil

Vedana, Luiz Alberto; Philipp, Ruy Paulo; Sommer, Carlos Augusto

doi:10.1590/2317-4889201720170019

Luiz Alberto Vedana ^**Corresponding author.

Professor of the Faculty of Engineering, Centro Universitário Ritter dos Reis - UniRitter, Porto Alegre (RS), Brazil. E-mail: luizvedana@gmail.com

Ruy Paulo Philipp

Professor of the Departamento de Mineralogia e Petrologia (DEMIPE), Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre (RS), Brazil. E-mails: ruy.philipp@ufrgs.br, casommer@sinos.net

Carlos Augusto Sommer

Professor of the Department of Geodesy - UFRGS, Porto Alegre (RS), Brazil. E-mail: casommer@sinos.net

*Corresponding author.

Figures (13)
Tables (4)

Thumbnail

Figure 1:
(A) Location of the study area in the context of South America. (B) Geologic map of the southern Brazilian and Uruguay shields, map and data compiled by Philipp et al. (2016Philipp R.P., Pimentel M.M., Chemale Jr. F. 2016. Tectonic evolution of the Dom Feliciano belt in Southern Brazil: geological relationships and U-Pb geochronology. Brazilian Journal of Geology, 46(Suppl 1):83-104.). Shear zones: (1) Itajaí-Perimbó; (2) Major Gercino; (3) Santana da Boa Vista; (4) Dorsal de Canguçu; (5) Passo do Marinheiro; (6) Ibaré; (7) Sarandi del Yí; (8) Sierra Ballena; (9) Cerro Amaro; (10) Arroio Grande.

Thumbnail

Figure 2:
Geological map of the São Gabriel Terrane. Cities: SS -- São Sepé; CS - Caçapava do Sul; VN - Vila Nova do Sul; LS - Lavras do Sul; DP - Dom Pedrito; B - Bagé. Shear zones: SZPVN - Shear Zone Passinho/Vila Nova; SZI - Shear Zone Ibaré; SZCS - Shear Zone Caçapava do Sul; DEF - Dom Feliciano Event. Modified from Philipp et al. (2016Philipp R.P., Pimentel M.M., Chemale Jr. F. 2016. Tectonic evolution of the Dom Feliciano belt in Southern Brazil: geological relationships and U-Pb geochronology. Brazilian Journal of Geology, 46(Suppl 1):83-104.).

Thumbnail

Figure 3:
Geological map of the Palma region, central portion of the São Gabriel Terrane. Modified from Laux et al. (2012Laux J.H., Bongiolo E.M., Klein C., Iglesias C.M.F. 2012. Mapa Geológico Lagoa da Meia Lua SH-21-Z-B-VI, escala 1:100.000. Porto Alegre, CPRM - Serviço Geológico do Brasil, v. 1.).

Thumbnail

Figure 4:
(A) Basalt outcrop near of the Palma stream. (B) Macroscopic aspect. (C) and (D) Photomicrographs (crossed nicols) of plagioclase phenocrysts and matrix. (E) and (F) Vesicle filled by epidote, carbonate and quartz (in “E” plane-polarized light and “F” cross-polarized light).

Thumbnail

Figure 5:
Chemical classifications diagrams. (A) Total Alcalis Silica (TAS) diagram (Cox et al. 1979Cox K.G., Bell J.D., Pankhurst R.J. 1979. The Interpretation of Igneous Rocks. London, George Allen & Unwin, 450 p.). (B) Alcalis vs. alumina diagram (Shand 1943Shand S.J. 1943. The Eruptive Rocks, 2nd ed. New York, John Wiley, 444 p.). (C) AFM (Irvine & Baragar 1971Irvine T.N., Baragar W.R.A. 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences, 8(5):523-548.). (D) FeO/MgO vs SiO₂ (Miyashiro 1974Miyashiro A. 1974. Volcanic rock series in island arcs and active continental margins. American Journal of Science, 274(4):321-355.). (E) Al-Fe+Ti-Mg diagram (Jensen 1976Jensen L.S. 1976. A new cation plot for classifying subalkaline volcanic rocks. Ontario Division of Mines, Miscellaneous, 66 p.). (F) K2O vs SiO₂ (Le Maitre et al. 1989Le Maitre R.W., Bateman P., Dudek A., Keller J., Lameyre J., Le Bas M.J., Sabine P.A., Schmid R., Sörensen H., Streckeisen A., Wooleen A.R., Zanettin B. 1989. A Classification of lgneos Rocks and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. Blackwell Scientific Publications, Oxford.).

Thumbnail

Figure 6:
(A) and (B) Classification of rocks using trace elements according to Winchester and Floyd (1977Winchester J.A., Floyd P.A. 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology, 20:325-343.) diagram.

Thumbnail

Figure 7:
Multi-element diagrams (spidergrams) normalized to primitive-mantle. (A) Palma mafic rocks and High-Ti samples from Ramada (Sommer et al. 2005Sommer C.A, Lima E., Nardi L.V.S., Figueiredo A.M.G., Pierosan R. 2005. Potassic and low- and high-Ti mildly alkaline volcanism in the Neoproterozoic Ramada Plateau, southermost Brazil. Journal of South American Earth Sciences, 18(3):237-254., Matté et al. 2016Matté V., Sommer C.A., Lima E.F., Philipp R.P., Basei M.A.S. 2016. Post-collisional Ediacaran volcanism in oriental Ramada Plateau, southern Brazil. Journal of South American Earth Sciences, 71:201-222.) and Taquarembó (Wildner et al. 2002Wildner W., Lima E.F., Nardi L.V.S., Sommer C.A. 2002. Volcanic cycles and setting in the Neoproterozoic III to Ordovician Camaquã Basin succession in Southern Brazil: Characteristics of post-collisional magmatism. Journal of Volcanology and Geothermal Research, 118(1-2):261-283.) plateaus. (B) Palma mafic rocks and Low-Ti samples from Ramada and Taquarembó plateaus. The dates of High-K Stromboli Basalts (Francalanci et al. 1999Francalanci L., Tommasini S., Conticelli S., Davies G.R. 1999. Sr isotope evidence for short magma residence time for the 20th century activity at Stromboli volcano, Italy. Earth and Planetary Science Letters, 167(1-2):61-69.) and Medium-K Honshu Basalts (Gust et al. 1997Gust D.A., Arculus R.J., Kersting A.B. 1997. Aspects of magma sources and processes in the Honshu Arc. The Canadian Mineralogist, 35(2):347-365.).

Thumbnail

Figure 8:
(A) Rare earth elements normalized to chondrite (Nakamura 1974Nakamura N. 1974. Determination of REE, Ba, Fe, Mg, Na and K in carbonaceous and ordinary chondrites. Geochimica et Cosmochimica Acta, 38(5):757-775.). (B) Rare earth elements normalized to ocean-island basalt (OIB) (Sun and McDonough 1989Sun S.S., McDonough W.F. 1989. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. Geological Society of London Special Publication, 42:313-345.). Dates of Taquarembó Plateau are found in Wildner et al. 2002Wildner W., Lima E.F., Nardi L.V.S., Sommer C.A. 2002. Volcanic cycles and setting in the Neoproterozoic III to Ordovician Camaquã Basin succession in Southern Brazil: Characteristics of post-collisional magmatism. Journal of Volcanology and Geothermal Research, 118(1-2):261-283. and the Ramada Plateau in Sommer et al. 2005Sommer C.A, Lima E., Nardi L.V.S., Figueiredo A.M.G., Pierosan R. 2005. Potassic and low- and high-Ti mildly alkaline volcanism in the Neoproterozoic Ramada Plateau, southermost Brazil. Journal of South American Earth Sciences, 18(3):237-254. and Matté et al. 2016Matté V., Sommer C.A., Lima E.F., Philipp R.P., Basei M.A.S. 2016. Post-collisional Ediacaran volcanism in oriental Ramada Plateau, southern Brazil. Journal of South American Earth Sciences, 71:201-222..

Thumbnail

Figure 9:
(A) Tectonic discrimination according to Pearce and Cann (1973Pearce J.A., Cann J.R. 1973. Tectonic setting of basic volcanic rocks determined using trace element analyses. Earth Planetary Science Letters, 19(2):290-300.) diagrams. (B) Tectonic discrimination according to Meschede (1986Meschede M. 1986. A method of discriminating between different types of Mid-Ocean Ridge Basalts and continental tholeiites with the Nb-Zr-Y diagram. Chemical Geology, 56:207-218.) diagram. Data of Taquarembó Plateau are found in Wildner et al. 2002Wildner W., Lima E.F., Nardi L.V.S., Sommer C.A. 2002. Volcanic cycles and setting in the Neoproterozoic III to Ordovician Camaquã Basin succession in Southern Brazil: Characteristics of post-collisional magmatism. Journal of Volcanology and Geothermal Research, 118(1-2):261-283. and the Ramada Plateau in Sommer et al. 2005Sommer C.A, Lima E., Nardi L.V.S., Figueiredo A.M.G., Pierosan R. 2005. Potassic and low- and high-Ti mildly alkaline volcanism in the Neoproterozoic Ramada Plateau, southermost Brazil. Journal of South American Earth Sciences, 18(3):237-254. and Matté et al. 2016Matté V., Sommer C.A., Lima E.F., Philipp R.P., Basei M.A.S. 2016. Post-collisional Ediacaran volcanism in oriental Ramada Plateau, southern Brazil. Journal of South American Earth Sciences, 71:201-222..

Thumbnail

Figure 10:
(A) V vs Ti diagram Shervais (1982Shervais J.W. 1982. Ti-V plots and the petrogenesis of modern ophiolitic lavas. Earth Planetary Science Letters, 59(1):101-118.) diagram. (B) Nb/Yb vs TiO2/Yb diagram (after Pearce 2008Pearce J.A. 2008. Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust. Lithos, 100(1-4):14-48.). (C) Th/Yb vs Nb/Yb diagram (Pearce 2008Pearce J.A. 2008. Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust. Lithos, 100(1-4):14-48.). Dates of Taquarembó Plateau are found in Wildner et al. 2002Wildner W., Lima E.F., Nardi L.V.S., Sommer C.A. 2002. Volcanic cycles and setting in the Neoproterozoic III to Ordovician Camaquã Basin succession in Southern Brazil: Characteristics of post-collisional magmatism. Journal of Volcanology and Geothermal Research, 118(1-2):261-283. and the Ramada Plateau in Sommer et al. 2005Sommer C.A, Lima E., Nardi L.V.S., Figueiredo A.M.G., Pierosan R. 2005. Potassic and low- and high-Ti mildly alkaline volcanism in the Neoproterozoic Ramada Plateau, southermost Brazil. Journal of South American Earth Sciences, 18(3):237-254. and Matté et al. 2016Matté V., Sommer C.A., Lima E.F., Philipp R.P., Basei M.A.S. 2016. Post-collisional Ediacaran volcanism in oriental Ramada Plateau, southern Brazil. Journal of South American Earth Sciences, 71:201-222..

Thumbnail

Figure 11:
Cathodoluminescence image of analyzed zircons with indications of U-Pb ages in millions of years of the: (A) LV-53 sample and (B) LV-70 sample.

Thumbnail

Figure 12:
Concordia plot of U-Pb zircon data for the sample LV-53 of andesitic basalt from the Acampamento Velho Formation.

Thumbnail

Figure 13:
(A) Concordia plot of U-Pb zircon data for the sample LV-70 of basalt from the Acampamento Velho Formation. (B) Concordia of U-Pb zircon data for the sample LV-70 with inherited xenocrystals.

Thumbnail

Table 1:
Geochemical data from five of representative samples of the Acampamento Velho Formation located in Palma region.

Thumbnail

Table 2:
LA-ICP-MS U-Pb results for igneous zircons from the sample LV-53 of the Acampamento Velho Formation.

Thumbnail

Table 3:
LA-ICP-MS U-Pb results for igneous and inherited zircons from the sample LV-70 of the Acampamento Velho Formation.

Thumbnail

Table 4:
Geochronological data of the volcanic rocks of Camaquã Basin.

Sample	LV-53	LV-55	LV-65	LV-70	8140A
SiO₂	53.31	53.05	51.31	49.86	57.75
Al₂O₃	18.28	17.15	17.33	13.95	15.92
Fe₂O₃	7.86	8.27	8.84	10.86	6.48
MnO	0.14	0.13	0.15	0.20	0.26
MgO	4.14	5.50	5.34	7.85	3.83
CaO	7.33	6.87	7.88	9.65	4.23
Na₂O	3.18	4.42	4.09	2.53	3.41
K₂O	1.69	0.43	0.88	1.66	1.40
TiO₂	1.00	1.05	1.17	1.13	0.58
P₂O₅	0.24	0.21	0.20	0.35	0.12
LOI	2.6	2.7	2.6	1.6	5.8
TOTAL	99.77	99.82	99.82	99.70	99.83
V	178	170	194	284	127
Rb	43.3	12.6	28.0	44.4	42.2
Sr	505.9	424.0	466.2	492.8	221.5
Y	20.6	23.1	24.5	21.2	15.7
Zr	135.5	129.1	131.7	104.9	89.6
Nb	7.0	5.1	6.0	6.3	4.2
Cs	0.6	0.2	0.8	1.1	2.0
Ba	541	232	189	1036	495
La	15.3	15.8	11.2	16.1	16.6
Ce	31.7	33.9	24.4	34.9	26.7
Pr	4.00	4.00	3.15	4.39	3.36
Nd	16.9	16.8	13.5	19.2	13.4
Sm	3.74	3.83	3.57	4.75	2.50
Eu	1.29	1.20	1.35	1.46	0.81
Gd	3.74	3.92	4.53	4.46	2.69
Tb	0.61	0.69	0.68	0.70	0.44
Dy	3.63	4.20	4.38	3.64	2.86
Ho	0.81	0.90	0.91	0.74	0.59
Er	2.20	2.61	2.51	2.19	1.71
Tm	0.36	0.33	0.40	0.36	0.25
Yb	2.34	2.43	2.52	2.13	1.59
Lu	0.32	0.35	0.39	0.31	0.24
Pb	1.7	1.7	1.0	3.8	2.0
Th	3.0	2.7	1.8	3.0	3.2
U	1.0	0.6	0.5	0.9	0.9

Spot	Results
Spot	207/235	1 σ	206/238	1 σ	C.C	238/206	1 σ	207/206	1 σ	208/206	1 σ	*Total Pb
20.1	0.7381	0.0163	0.0904	0.0011	0.24	11.0667	0.1337	0.0592	0.0013	0.1386	0.0293	0.00
9.1	0.7351	0.0131	0.0907	0.0007	0.95	11.0295	0.0852	0.0588	0.0010	0.1270	0.0082	0.00
24.1	0.7449	0.0189	0.0913	0.0012	0.86	10.9520	0.1463	0.0592	0.0015	0.1858	0.0170	0.14
18.1	0.7458	0.0268	0.0914	0.0015	0.67	10.9384	0.1743	0.0592	0.0022	0.4052	0.0283	0.45
10.1	0.7408	0.0161	0.0915	0.0008	0.89	10.9329	0.0947	0.0587	0.0012	0.1217	0.0069	0.04
7.1	0.7447	0.0179	0.0917	0.0009	0.54	10.9071	0.1012	0.0589	0.0014	0.1022	0.0101	1.31
22.1	0.7555	0.0324	0.0935	0.0017	0.43	10.6988	0.1896	0.0586	0.0027	0.2585	0.0127	0.45
4.1	0.7579	0.0463	0.0923	0.0017	0.29	10.8353	0.1998	0.0596	0.0040	0.2041	0.0138	0.49
2.1	0.7750	0.0159	0.0948	0.0008	0.53	10.5508	0.0887	0.0593	0.0012	0.1240	0.0162	2.70
5.1	0.7244	0.0175	0.0890	0.0008	0.42	11.2404	0.1044	0.0591	0.0014	0.1520	0.0176	0.11
12.1	0.7262	0.0137	0.0899	0.0007	0.91	11.1181	0.0894	0.0586	0.0010	0.1043	0.0069	1.75
15.1	0.7749	0.0137	0.0959	0.0011	0.95	10.4319	0.1184	0.0586	0.0009	0.1165	0.0084	0.12
1.1	0.7117	0.0143	0.0870	0.0007	0.93	11.4896	0.0939	0.0593	0.0012	0.1030	0.0067	5.51
8.1	0.8377	0.0263	0.1019	0.0011	0.96	9.8099	0.1087	0.0596	0.0020	0.2153	0.0642	0.86
16.1	0.7891	0.0137	0.0979	0.0011	0.87	10.2196	0.1160	0.0585	0.0009	0.1661	0.0036	0.90
17.1	0.7159	0.0250	0.0875	0.0014	0.39	11.4325	0.1797	0.0594	0.0022	0.1889	0.0658	1.37
17.2	0.6840	0.0146	0.0837	0.0010	0.98	11.9410	0.1436	0.0592	0.0012	0.2876	0.0432	1.94
21.1	0.6983	0.0169	0.0857	0.0011	0.96	11.6638	0.1479	0.0591	0.0015	0.1119	0.0325	0.00
3.2	1.7819	0.0315	0.1721	0.0014	0.88	5.8114	0.0466	0.0751	0.0013	0.0744	0.0014	0.04
Spot	Estimated values (ppm)			Calculed ages					Conc. (%)
Spot	Pb	Th	U	Th/U	T206/238	1 σ	T207/206	1 σ	Conc. (%)
20.1	115.3	366.9	1172.1	0.313	0.558	0.006	0.576	0.044	96
9.1	201.4	669.9	1921.4	0.349	0.559	0.004	0.560	0.036	99
24.1	80.3	460.6	767.6	0.600	0.563	0.007	0.573	0.055	98
18.1	48.7	510.4	407.6	1.252	0.564	0.009	0.573	0.079	98
10.1	106.2	407.9	1040.7	0.392	0.564	0.005	0.557	0.046	101
7.1	68.3	201.1	696.1	0.289	0.565	0.005	0.564	0.052	100
22.1	32.9	232.5	290.7	0.800	0.576	0.010	0.553	0.096	104
4.1	19.8	118.8	181.4	0.655	0.569	0.010	0.588	0.143	96
2.1	119.5	417.1	1150.5	0.363	0.584	0.005	0.578	0.044	100
5.1	72.6	384.4	720.2	0.534	0.549	0.005	0.569	0.053	96
12.1	292.8	1322.0	2943.9	0.449	0.555	0.004	0.551	0.039	100
15.1	346.6	1167.6	3347.9	0.349	0.590	0.006	0.553	0.035	106
1.1	115.0	401.9	1221.1	0.329	0.538	0.004	0.578	0.044	93
8.1	130.5	1399.3	1087.8	1.286	0.626	0.007	0.589	0.072	106
16.1	435.3	2219.4	3974.8	0.558	0.602	0.007	0.548	0.033	109
17.1	132.6	1225.0	1087.0	1.127	0.541	0.008	0.580	0.078	93
17.2	170.0	1130.2	1665.2	0.679	0.518	0.006	0.576	0.045	90
21.1	120.8	586.2	1158.0	0.506	0.530	0.006	0.570	0.058	93
3.2	158.4	220.2	844.1	0.261	1.024	0.008	1.071	0.034	95

Spot	Results
Spot	207/235	1 σ	206/238	1 σ	C.C	238/206	1 σ	207/206	1 σ	208/206	1 σ	*Total Pb
9.1	0.6968	0.0454	0.0876	0.0025	0.73	11.4095	0.3263	0.0577	0.0037	0.1297	0.0333	0.34
11.1	0.7635	0.0322	0.0926	0.0023	0.85	10.8022	0.2663	0.0598	0.0021	0.2276	0.0244	3.46
2.1	0.7403	0.0335	0.0927	0.0012	0.34	10.7893	0.1436	0.0579	0.0026	0.3822	0.0488	0.90
5.1	0.7664	0.0196	0.0932	0.0009	0.96	10.7254	0.1018	0.0596	0.0014	0.3934	0.0610	1.79
5.2	0.7656	0.0225	0.0942	0.0010	0.91	10.6123	0.1131	0.0589	0.0016	0.1988	0.0176	1.00
2.3	0.7815	0.0325	0.0945	0.0023	0.73	10.5782	0.2600	0.0600	0.0021	0.2738	0.0425	3.05
8.1	0.7801	0.0310	0.0952	0.0022	0.98	10.5017	0.2411	0.0594	0.0022	0.1911	0.0202	4.43
3.1	0.7205	0.0299	0.0889	0.0012	0.31	11.2500	0.1471	0.0588	0.0023	1.0277	0.4188	0.00
10.1	6.1754	0.1989	0.3673	0.0087	0.94	2.7227	0.0644	0.1219	0.0029	0.2054	0.0027	0.09
10.2	6.2524	0.1984	0.3732	0.0087	0.98	2.6797	0.0626	0.1215	0.0029	0.2158	0.0037	0.12
10.3	6.2633	0.1996	0.3704	0.0087	0.84	2.6996	0.0635	0.1226	0.0029	0.2093	0.0036	0.13
10.4	6.4041	0.1959	0.3800	0.0086	0.93	2.6313	0.0599	0.1222	0.0028	0.1858	0.0029	0.08
4.2	0.7251	0.0186	0.0887	0.0009	0.97	11.2755	0.1087	0.0593	0.0014	0.2450	0.0169	1.05
1.3	1.2232	0.0355	0.1336	0.0014	0.20	7.4854	0.0802	0.0664	0.0018	0.1051	0.0080	0.22
1.2	1.2199	0.0330	0.1352	0.0014	0.59	7.3939	0.0747	0.0654	0.0016	0.1332	0.0046	0.17
Spot	Estimated values (ppm)			Calculed ages					Conc. (%)
Spot	Pb	Th	U	Th/U	T206/238	1 σ	T207/206	1 σ	Conc. (%)
9.1	23.0	82.2	228.3	0.360	0.542	0.015	0.517	0.138	104
11.1	53.6	362.0	449.4	0.806	0.571	0.013	0.597	0.077	95
2.1	65.8	787.5	487.7	1.615	0.571	0.007	0.527	0.092	108
5.1	103.6	876.4	906.9	0.966	0.575	0.005	0.590	0.051	97
5.2	92.8	600.5	874.0	0.687	0.581	0.006	0.564	0.058	102
2.3	68.1	657.3	571.7	1.150	0.582	0.014	0.602	0.078	96
8.1	68.2	567.4	788.5	0.720	0.586	0.013	0.582	0.080	100
3.1	14.8	350.8	99.8	3.516	0.549	0.007	0.559	0.080	98
10.1	125.7	205.9	276.1	0.746	2.017	0.041	1.985	0.043	101
10.2	130.2	222.0	288.2	0.770	2.044	0.041	1.979	0.042	103
10.3	141.8	238.1	313.6	0.759	2.031	0.041	1.995	0.043	101
10.4	174.1	259.8	384.7	0.675	2.076	0.040	1.989	0.040	104
4.2	114.7	826.3	1080.7	0.765	0.548	0.005	0.578	0.051	94
1.3	57.8	141.0	399.7	0.353	0.808	0.008	0.819	0.058	98
1.2	63.7	175.9	425.5	0.413	0.818	0.008	0.788	0.052	103

Location	Lithoestratiphic unit	Rock type	Age	Dated mineral	Method	Source
São Gabriel Terrane
Lavras do Sul	Lavras do Sul Granite	Granodiorite	580±7 Ma	Zircon	U-Pb SHRIMP	Remus et al. 1997
São Gabriel - Palma	Jaguari Granite	Syenogranite	568±7 Ma	Zircon	U/Pb LA-ICP-MS	*Gastal et al.* 2010**Gastal M.C., Lafon J.M., Chemale Jr. F. 2010. U-Pb and Pb-Pb zircon ages of Neoproterozoic-Eopaleozoic granites from the western portion of the southerm Brazilian Shield. In: VII South American Symposium on Isotopic Geology. Brasília, Short Papers, p.105-108.
Vila Nova do Sul	Cerro da Cria Granite	Syenogranite	564±4 Ma	Bulk Rock	Rb-Sr	Naime & Nardi 1991Naime R.H., Nardi L.V.S. 1991. O Granito da Ramada, porção oeste do Escudo Sul-riograndense: geologia, petrologia e geoquímica. Revista Brasileira de Geociências, 21(3):266-274.
FIDA Mine	Caçapava do Sul Granite	Granodiorite	562±8 Ma	Zircon	U-Pb SHRIMP	*Remus et al.* 2000**Remus M.V.D., Hartmann L.A., McNaughton N.J., Groves D.I., Fletcher I.R. 2000. The link between hydrothermal epigenetic copper mineralization and the Caçapava Granite of the Brasiliano Cycle in southern Brazil. Journal of South American Earth Sciences, 13(3):191-216.
Caçapava do Sul BR-392	Caçapava do Sul Granite	Granodiorite	541±11 Ma		U-Pb SHRIMP	Leite 1998Leite J.A.D., Hartmann L.A., McNaughton N.J., Chemale Jr. F. 1998. SHRIMP U/Pb zircon geochronology of Neoproterozoic juvenile and crustal-reworked terranes in southernmost Brazil. International Geology Review, 40(8):688-705.
Pedreira ao sul de São Sepé	São Sepé Granite	Monzogranite	559±7 Ma			Remus et al. 1997
Pedreira ao sul de São Sepé	São Sepé Granite	Syenogranite	539±7 Ma		U-Pb LA-ICP-MS	*Gastal et al.* 2010**Gastal M.C., Lafon J.M., Chemale Jr. F. 2010. U-Pb and Pb-Pb zircon ages of Neoproterozoic-Eopaleozoic granites from the western portion of the southerm Brazilian Shield. In: VII South American Symposium on Isotopic Geology. Brasília, Short Papers, p.105-108.
Vila Nova do Sul	Ramada Granite	Syenogranite	464±13 Ma	Bulk Rock	Rb/Sr	Naime & Nardi 1991Naime R.H., Nardi L.V.S. 1991. O Granito da Ramada, porção oeste do Escudo Sul-riograndense: geologia, petrologia e geoquímica. Revista Brasileira de Geociências, 21(3):266-274.
Pelotas Batholith
Porto Alegre	Santana Granite	Perthite Granite	600±10 Ma	Zircon	U-Pb LA-ICP-MS	*Koester et al. 2001*Koester E., Soliani Jr. E., Leite J.A.D., Hartmann L.A., Fernandes L.A.D., McNaughton N.J., Santos J.O.S., Oliveira L.D. 2001. SHRIMP U-Pb age for the emplacement of Santana granite and reactivation of the Porto Alegre Suture, southern Brazil. Journal of South American Earth Sciences, 14(1):91-99.
Canguçu	Arroio Moinho Granite	Syenogranite	595±1 Ma		U-Pb TIMS	*Babinsky et al.* 1996**Babinski M., Chemale Jr. F., Hartmann L.A., Van Schmus W.R., Silva L.C. 1996. Juvenile accretion at 750-700 Ma in Southern Brazil. Geology, 24(5):439-442.
Butiá	Ana Dias Rhyolite	Rhyolite	581±1.9 Ma		U-Pb LA-ICP-MS	*Oliveira et al.* 2014**Oliveira C.H.E., Chemale Jr. F., Jelinek A.R., Bicca M.M., Phillip R.P. 2014. U-Pb and Lu-Hf isotopes applied to the evolution of the late to post-orogenic transtensional basins of the Dom Feliciano Belt, Brazil. Precambrian Research, 246:240-255.
Piratini	Rhyolite	Rhyolite	551±7 Ma		U-Pb LA-ICP-MS	Zanon et al. 2010
Bom Jardim Group
Casa de Pedra Region (SBC-C)	Cerro da Angélica Formation	Granitic intrusion	594±3 Ma		Zircon	U-Pb TIMS	Janikian 2004Janikian L. 2004. Seqüências deposicionais e evolução paleoambiental do Grupo Bom Jardim e da Formação Acampamento Velho, Supergrupo Camaquã, Rio Grande do Sul. PhD Thesis, Instituto de Geociências, Universidade de São Paulo, São Paulo, 189 p.
Lavras do Sul (SBC-Oc)	Hilário Formation	Andesito	590±6 Ma	Plagioclase (andesite)	Ar-Ar
BR-153 (SBC-C)		Lapilli tuff	589±5 Ma	Zircon	U-Pb TIMS
BR-153 (SBC-C)		Lapilli tuff	590±6 Ma	Zircon	U-Pb TIMS
Passo do Hilário (SBC-Oc)		Andesite	588±7 Ma	Plagioclase (andesite)	Ar-Ar
Lavras do Sul (SBC-Oc)		Andesite	586±8 Ma	Plagioclase (andesite)	Ar-Ar
Casa de Pedra (SBC-C)	Cerro da Angélica Formation	Basic intrusion	555±22 Ma	Zircon	U-Pb TIMS
Fazenda Fomento (SBC-C)	Picada das Graças Formation	Subvolcanic andesite	550±21 Ma
Bom Jardim (SBC-C)	Fm. Hilário	Rhyolite	547±9 Ma
Lavras do Sul		Andesite	512±20 Ma	Bulk Rock	K-Ar	Ribeiro & Teixeira 1970Ribeiro M., Teixeira C.A.S. 1970. Datações de rochas do Rio Grande do Sul e sua influência nos conceitos estratigráficos e geotectônicos locais. Inheríngia, Série Geológica, 3:109-120.
?		Volcanic rock	510-535 Ma		Rb/Sr	*Cordani et al.1974*Cordani U.G., Halpern M., Berenholc M. 1974. Comentários sobre as determinações geocronológicas da Folha de Porto Alegre. In: Carta Geológica do Brasil ao Milionésimo. Texto explicativo das folhas de Porto Alegre e Lagoa Mirim, DNPM, Brasília, p. 70-77.
Sub-Basin Camaquã Ocidental		Andesite	510±40 Ma		K-Ar	Cordani (apudRibeiro & Teixeira 1970Ribeiro M., Teixeira C.A.S. 1970. Datações de rochas do Rio Grande do Sul e sua influência nos conceitos estratigráficos e geotectônicos locais. Inheríngia, Série Geológica, 3:109-120.)
Lavras do Sul SBC-Oc			495±20 Ma 511±20 Ma			Minioli & Kawashita 1971Minioli B., Kawashita K. 1971. Contribuição à estratigrafia do Eo-paleozóico do Escudo Sulrio-grandense. In: 25° Congresso Brasileiro de Geologia. São Paulo, Anais..., p. 193-198.
			523±20 Ma	K-Ar
			528±20 Ma	K-Ar
Acampamento Velho Formation
Western Camaquã Sub-basin	Acampamento Velho Formation	Rhyolite pebble	580±13 Ma	Zircon	U-Pb SHRIMP	*Janikian et al.* 2012**Janikian L., Almeida R.P., Fragoso-Cesar A.R.S., Martins V.T.S., Dantas E.L., Tohver E., McReath I., D’Agrella-Filho M.S. 2012. Ages (U-Pb SHRIMP and LA ICPMS) and stratigraphic evolution of the Neoproterozoic volcano-sedimentary successions from the extensional Camaquã Basin, Southern Brazil. Gondwana Research, 21(2-3):466-482.
Western Camaquã Sub-basin		Rhyolite pebble	570±5 Ma		U-Pb SHRIMP
Central Camaquã sub-basin		Hypabissal rhyolite	572±6 Ma		U-Pb TIMS
E - Ramada Plateau SBC-Oc		Rhyolite	574±7 Ma			Janikian 2004Janikian L. 2004. Seqüências deposicionais e evolução paleoambiental do Grupo Bom Jardim e da Formação Acampamento Velho, Supergrupo Camaquã, Rio Grande do Sul. PhD Thesis, Instituto de Geociências, Universidade de São Paulo, São Paulo, 189 p.
Sub-Basin Camaquã Ocidental		Rhyolite	573±18 Ma			Chemale Jr. 2000Chemale Jr. F. 2000. Evolução Geológica do Escudo Sul-Riograndense. In: Holz M., De Ros L.F. (eds.) Geologia do Rio Grande do Sul. Centro de Investigação do Gondwana, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, p. 13-52.
Ramada Plateau		Welded tuff	560±2 Ma		U-Pb ICP-MS-LA	*Matté et al.* 2016**Matté V., Sommer C.A., Lima E.F., Philipp R.P., Basei M.A.S. 2016. Post-collisional Ediacaran volcanism in oriental Ramada Plateau, southern Brazil. Journal of South American Earth Sciences, 71:201-222.
		Traquite	560±14 Ma
		Rhyolite	562±2 Ma
São Gabriel - Palma		Basalt	559±17 Ma	Bulk Rock	K-Ar	*Teixeira et al.* 1982**Teixeira W. 1982. Folhas SH.22 - Porto Alegre, SI.22 - Lagoa Mirim e SH.21 - Uruguaiana. Interpretação dos Dados Radiométricos e Evolução Geocronológica. Projeto RADAMBRASIL. Florianópolis (Relatório Interno, Inédito).
Ramada Plateau		Rhyolite	549±5 Ma	Zircon	U-Pb SHRIMP	*Sommer et al.* 2005**Sommer C.A, Lima E., Nardi L.V.S., Figueiredo A.M.G., Pierosan R. 2005. Potassic and low- and high-Ti mildly alkaline volcanism in the Neoproterozoic Ramada Plateau, southermost Brazil. Journal of South American Earth Sciences, 18(3):237-254.
Ramada Plateau/Ramada Granite		Rhyolite	525±3 Ma			*Cordani et al.* 1974**Cordani U.G., Halpern M., Berenholc M. 1974. Comentários sobre as determinações geocronológicas da Folha de Porto Alegre. In: Carta Geológica do Brasil ao Milionésimo. Texto explicativo das folhas de Porto Alegre e Lagoa Mirim, DNPM, Brasília, p. 70-77.
Platô da Ramada		Ignimbrite	504±20 Ma 533±20 Ma	Bulk Rock	K-Ar RT	Minioli & Kawashita 1971Minioli B., Kawashita K. 1971. Contribuição à estratigrafia do Eo-paleozóico do Escudo Sulrio-grandense. In: 25° Congresso Brasileiro de Geologia. São Paulo, Anais..., p. 193-198.
Guaritas Group
Pedra da Arara-Cerro do Diogo	Rodeio Velho Member	Basalt	547±6.3 Ma	Zircon	U-Pb ICP-MS-LA		*Almeida et al.* 2009**Almeida R.P., Janikian L., Fragoso-Cesar A.R.S., Marconato A. 2009. Evolution of a rift basin dominated by subaerial deposits: The Guaritas Rift, Early Cambrian, Southern Brazil. Sedimentary Geology, 217(1-4):30-51.
?	Guaritas Formation	?	525 Ma	Clay Illite	K-Ar	Bonhome & Ribeiro 1983Bonhome M.E., Ribeiro M.J., 1983. Datações K/Ar das argilas associadas à mineralização de cobre da Mina Camaquã e suas encaixantes. In: I Simpósio Sul-Brasileiro de Geologia. Sociedade Brasileira de Geologia. Atas… p. 82-88.
Sul-Leste de Caçapava do Sul	Pedra da Pintada Formation	Alluvial facies	522±10 Ma	Clay Illite	K-Ar	*Maraschin et al.* 2010**Maraschin A.J., Mizusaki A.M., Zwingmann H., Borba A.W., Sbrissa G.F., 2010. Illite authigenesis in sandstones of the Guaritas Allogroup (Early Paleozoic): Implications for the depositional age, stratigraphy and evolution of the Camaquã Basin (Southern Brazil). Journal of South American Earth Sciences, 29(2):400-411.
?	Rodeio Velho Member	Andesite	470±19 Ma	Zircon	U-Pb SHRIMP	*Hartmann et al., 1999*Hartmann L.A., Nardi L.V.S., Formoso M.L.L., Remus M.V.D., Lima E.F., Mexias A. 1999. Magmatism and metallogeny in the crustal evolution of Rio Grande do Sul shield, Brazil. Pesquisas em Geociências (UFRGS), 26(2):45-63.

[1] *Corresponding author.

Brasil

Brasil

Post-collisional basalts of the Acampamento Velho Formation, Camaquã Basin, São Gabriel Terrane, southernmost Brazil

Basaltos pós-colisionais da Formação Acampamento Velho, Bacia do Camaquã, Terreno São Gabriel, sul do Brasil

ABSTRACT: