A review of the geodynamic setting of the Volcanic Domain in the Juruena Magmatic Arc , southwestern Amazon Craton , Brazil , based on geochemical , UPb and Sm-Nd data

*Corresponding author Tiago B. Duarte E-mail address: tiago.duarte@cprm.gov.br

In SW Amazon Craton, along the boundary between the Ventuari-Tapajós (1.9 to 1.8 Ga) and the Rio Negro-Juruena (1.8 to 1.55 Ga) provinces, an association of volcanic rocks and related epizonal granitic plutons crop out as a volcanic belt with more than 600 km long.This set of rocks, here called the Volcanic Domain (VD), has been the target of several studies due to its metallogenic importance as well as to the understanding of the geodynamic evolution of the Southwestern Amazon Craton, and various geodynamic models are considered for this plutono-volcanism at about 1.8 Ga, including taphrogenesis, accretionary margin volcanic belt, and late-to post-orogenic extensional magmatism.In this work, based on whole rock geochemistry, and in U-Pb and Sm-Nd isotopic results we propose a geodynamic model that admit shifts in the tectonic regime through time and unifies the second and third interpretations above.We interpret the intermediate to acid, A-type, oxidized granitic and volcanic rocks from the Colíder Group and the Paranaíta Intrusive Suite as products of continental arc magmatism, whereas the acid, A-type reduced granitic and volcanic rocks resulted from late-stage extensional back-arc and forearc processes being respectively associated with the Teles-Pires Intrusive Suite and Roosevelt Group magmatism.The continental arc interpretation for the VD is supported by the following lines of evidence: (1) spatial arrangement of the VD in the shape of a volcanic belt; (2) the large volume of volcaniclastic deposits and related epizonal granitic intrusions; (3) variable chemical signatures ranging from subalkaline mafic compositions to high-K calc-alkaline, A-type oxidized granites, showing REE and trace element patterns similar to those of subcontinental lithospheric mantle sources enriched by subduction-zone fluids, and subordinate involvement of continental crust; (4) crystallization and Sm-Nd T DM model ages, respectively, ranging between 1820 and 1780 Ma, and from 2.40 to 1.84 Ga, with  Nd(t) values of -3.9 to +2.5, yielding an overlap in U-Pb and Sm-Nd ages of rocks from the Juruena Magmatic Arc; (5) the occurrence of epithermal-porphyry Au systems in the Alta Floresta Gold Province with ages compatible with those of the VD magmatic period.

Introduction
Previous works that focused on the geotectonic evolution of Proterozoic provinces in the southwestern Amazon Craton have consolidated a broad geodynamic model based on the successive accretion of magmatic arcs since 2.0 Ga until the end of the Mesoproterozoic (Cordani et al. 1979;Cordani and Neves 1982;Teixeira et al. 1989;Santos et al. 2000;Tassinari and Macambira 1999;and 2004;Cordani and Teixeira 2007;Santos et al. 2008).These successive events of oceanic crust subduction and continental accretion were driven by soft collision processes, as evidenced by Cordani and Teixeira (2007), and culminated in the assembly of the supercontinents Columbia or NUNA (Hoffman 1997;Rogers and Santosh 2002), and Rodinia (Greenville orogeny) at 1.8 and 1.0 Ga, respectively (Cordani et al. 2009).Tassinari (1996), Sato and Tassinari (1997), and Tassinari and Macambira (1999), based on mobilistic theories and Rb-Sr (whole rock) isotopic data, have suggested an Archean dynamic evolutionary model that includes the agglutination of crustal fragments and juvenile accretion processes.These authors proposed then the organization of the Amazon Craton into structural and geochronological provinces (Fig. 1).
In accretionary arc environments dominated by soft collision-induced crustal thickening, major continental uplift, as seen in large mountain ranges such as the Himalayas, and the exhumation of deep crustal layers are minimized, allowing volcanic covers and epizonal rocks to be preserved (Cordani and Teixeira 2007;Juliani et al. 2005).
The rocks of the Ventuari-Tapajós Province yield crystallization ages between 1.9 and 1.8 Ga; whereas crystallization ages for the rocks of the Rio Negro-Juruena FIGURE 1 -Distribution of the Geotectonic/Geochronological Provinces in the Amazon Craton and location of the study area in the detailed map.modified from Tassinari and Macambira (1999) with a detailed map of the SW portion of the Craton.
Province range from 1.8 to 1.55 Ga.A NW-SE oriented belt about 600 Km long and composed of well-preserved Paleoproterozoic volcanic rocks and plutonic counterparts is located in an intermediate position between the two provinces (Fig. 1) and defines the Juruena Magmatic Arc Volcanic Domain (Duarte et al. 2012).
Despite the number of published works, a unifying geodynamic evolutionary model for the Volcanic Domain has not been consolidated yet.The key point is whether the Volcanic Domain is related to accretionary processes that shaped the Juruena Magmatic Arc or to extensional postorogenic to anorogenic settings related to the Rio Negro-Juruena or Tapajós-Parima geotectonic evolution.
At the moment three distinctive geodynamic models are considered for this plutono-volcanism.The first model admits that the Volcanic Domain magmatism, called Teles-Pires (including group, magmatism, plutono-volcanism and other designations depending the author), is the result of process that characterizes the Columbia or NUNA taphrogenesis around 1.8 Ga.(Tassinari and Macambira 1999;Pinho et al. 2003;Cordani and Teixeira 2007;Cordani et al. 2009; Barros et al. 2009).
The second model recognizes the Volcanic Domain as an accretionary margin volcanic belt developed on the Ventuari-Tapajós Province at 1.8 Ga, which worked as an active continental margin, resulting in the formation of the Juruena Magmatic Arc (Santos et al. 2000;Souza et al. 2005;Santos et al. 2008;Duarte et al. 2012).Alternatively to the interpretations above, Barros et al. (2009), Alves et al. (2013), and Silva et al. (2014) admit that the Volcanic Domain is a lateto post-orogenic extensional magmatism developed within the Juruena Magmatic Arc.
This work carried out in the western sector of the Volcanic Domain (Fig. 2) brings together recent geological mapping, petrological, lithogeochemical and new important isotopic results of U-Pb (zircon) and whole-rock Sm-Nd data.The main goal is to understand the geodynamic processes and time intervals over which the Volcanic Domain was formed, to establish theoretical foundations based on the discussion of geological factors that allow us to apply them to the context of the Amazon Craton provinces (Rio Negro-Juruena and Ventuari-Tapajós), aiming at providing a more accurate division for these provinces within the study area.

Geology and evolution of the Juruena Magmatic Arc
Based on recent geochronological data, and on the current tectonic evolutionary model, the orogeny that gave rise to the Juruena Magmatic Arc (Fig. 2) started at 1820 Ma.Compressive stresses from SW to NE transported an oceanic crust (Bacaeri-Mogno Complex) toward the already stable Tapajós-Parima Province (cratonic margin) leading to plate subduction and consumption (Santos et al. 2000;Souza et al. 2005;Duarte et al. 2012).
The interaction of mantle and crustal sources in this accretionary environment generated hybrid magmas, which is supported by rocks with  Nd values ranging from slightly negative to positive (Santos et al. 2000;Pinho et al. 2003;Souza et al. 2005;Cordani and Teixeira 2007;Barros et al. 2009;Ribeiro and Duarte 2010).In the study area, rocks related to the earliest stages of subduction are distributed in a volcanic belt which is composed of hypabyssal granites from the Paranaíta Intrusive Suite (1820 to 1769 Ma) and volcanic/volcaniclastic rocks from the Colíder Group (1803 to 1766 Ma) (JICA/MMAJ 2000, 2001;Ribeiro and Duarte 2010;Duarte et al. 2012).Despite the strong ductile deformation, this volcanic domain is well preserved and called Teles-Pires Group undeformed domain and characterized by Pinho et al. (2003) and Barros et al. (2009).
To the east of the survey area, in the Peixoto de Azevedo and Alta Floresta regions (Fig. 2), volcanic rocks associated with granites yielding ages from 1810 to 1750 Ma are also recognized, including the Pium Granite (Alves et al. 2013), the Terra Nova Granite (Prado et al. 2013), and the Peixoto Granite (Silva et al. 2014).These rocks have an A-type signature (Whalen et al. 1987), consistent with those of back-arc settings in a post-collisional to anorogenic period of the Juruena Magmatic Arc, and attributed to the Teles-Pires magmatism (Silva et al. 1980;Pinho et al. 2003;Lacerda Filho 2004;Silva and Abram 2008).
In the study area, the Volcanic Domain occurs in tectonic contact along a transpressional WNW-ESE trending sinistral shear zone with medium to high-grade metamorphic rocks of the Juruena Complex (Ribeiro and Duarte 2010;Duarte et al. 2012), or with the Teles-Pires Group Deformed Domain (Barros et al. 2009).It contains predominantly plutonic rocks with ages ranging from 1787 to 1764 Ma, as well as the Bacaeri-Mogno Complex (Sm-Nd isochron age of 2.24 Ga, and  Nd(t) of +2.5), which is interpreted as oceanic crust remnant (Souza et al. 2005).This domain comprises the Vitória Plutonic Suite (1787 to 1765 Ma), the São Pedro (1796 to 1730 Ma) and São Romão (1780 to 1770 Ma) granites, and the Vespor Mafic Suite (1773 to 1764 Ma).Dispersed volcanic rocks in the Juruena Complex, apparently filling retroarc basins, are attributed to the Roosevelt Group (1760 to 1740 Ma) (Fig. 2).
The geological episode that left its high-grade deformation imprint on the Juruena Magmatic Arc was the collisional Quatro Cachoeiras orogeny (Rizzotto et al. 2004;Santos et al. 2008).In the southwest of the area, closer to the suture zone, this orogeny is revealed through metamorphic ages around 1640 Ma obtained on zircon rims of samples from the Jamari Complex (state of Rondônia), as well as by the presence of granulite-facies rocks.The orogeny was followed by postcollisional granitogenesis during the Mesoproterozoic, which nowadays is represented by the Serra da Providência Suite (1605 to 1505 Ma) (Tassinari et al. 1984).
Other events recorded by the regional stratigraphy are represented by graben-like basins, which are related to the Sunsás-Aguapeí orogeny, filled with sediments of the Beneficente Group, and the Piranhas dike swarms emplaced in the early Paleozoic (Santos et al. 2002;Duarte et al. 2012).

Volcanic Domain and Juruena Complex: field aspects and petrographic results
The Colíder Group is mostly composed of pyroclastic deposits and subordinate lavas with mainly acid to intermediate composition.The Paranaíta Intrusive Suite is composed of mesozonal to epizonal granites.Apparently, these rocks crop out in places where the pyroclastic deposits were eroded and as apophyses.Even though the Volcanic Domain has not shown evidence of regional metamorphism, it is affected by cataclastic shear bands striking E-W to NW-SE generating schistosity and microfratures.

Colíder Group
The Colíder Group rocks were grouped based on textural and compositional aspects into: (1) dacite, rhyodacite and rhyolite; (2) mafic; and (3) volcaniclastic.Dacite, rhyodacite, and rhyolite are aphanitic, fine-grained, phaneritic, or microporphyritic rocks with quartz and plagioclase phenocrysts.The groundmass shows microcrystalline and micropoikilitic devitrification textures, and commonly micrographic intergrowth and granophyric textures.Phenocrysts are quartz, plagioclase, alkali feldspar, biotite, and hornblende.The observed samples commonly present microfractures and associated hydrothermal alteration with various degrees of metasomatism.These microfractures are filled with an association of sericite + epidote + quartz ± pyrite ± chalcopyrite or calcite ± pyrite ± chalcopyrite.In addition, a more pervasive, intergranular hydrothermal alteration is composed of ultrafine sericite and limonite, with disseminated sulfides.This pervasive and regional hydrothermal alteration gives the rocks a characteristic reddish color.
The mafic rocks are greenish, fine-grained diabase, andesite, and phaneritic amphibolite.The diabase has ophitic to sub-ophitic texture with a groundmass composed of tabular plagioclase and augite.The plagioclase is often pseudomorphosed, partial or totally altered to clay minerals and saussurite.The augite is also pseudomorphosed and altered to uralite, biotite, chlorite, and calcite.Disseminated sub-millimeter sized magnetite and titanomagnetite are found as accessory minerals, but they may occur in concentrations up to 10%.Andesite has cryptocrystalline to microcrystalline devitrified groundmass and amygdala filled with quartz, chlorite, epidote, and calcite.The rocks are affected by fissurefilling hydrothermal alteration along microfractures filled with epidote, chlorite, calcite, pyrite, and chalcopyrite, and by a pervasive alteration with sericite, chlorite and disseminated Fe-Cu sulfides.
The volcaniclastic rocks are pyroclastic flows and fall deposits classified as welded ignimbrites and welded tuffs that characterize thick stratified and massive volcanogenic deposits.These rocks exhibit a discrete foliation with compacted and stretched pumices and clasts (eutaxitic texture) and complex flow folds as well as lithophysae textures in the strongly welded tuffs and ignimbrites.The eutaxitic and vitriclastic textures are well evidenced by a discontinuous foliation resulted from stretched and flattened devitrified shards, fiammes, pumices, lithic fragments, embayed quartz, and angular feldspar fragments alternating with devitrified ash bands.Hydrothermal processes, similar to those described for the other volcanic rocks, also affect this set of rocks.Pervasive sericitization replaced most aphanitic groundmass mineralogy and feldspar crystal fragments.Epidote and chlorite are less common and occur replacing hornblende and biotite crystal fragments and mafic lithoclasts.Microfractures are filled with an association of sericite + quartz + calcite + sulfide (pyrite and chalcopyrite).Calcite-filled fractures cut across the microfractures representing a late stage hydrothermal alteration.

Paranaíta Intrusive Suite
The Paranaíta Intrusive Suite is composed mostly of porphyritic granodiorite to monzogranite and granophyre with rocks showing hypidiomorphic-granular, porphyritic to glomeroporphyritic, granophyric and micrographic textures.Phenocrysts are of plagioclase and perthitic microcline in a granular or intergrown groundmass of quartz, feldspar (plagioclase and microcline), biotite, and hornblende.Magnetite, apatite, fluorite, zircon, and titanomagnetite occur as accessory minerals.In some samples, crystals of quartz show undulose extinction and sutured grain boundaries that are indicative of the incipient deformation.Plagioclase is commonly replaced by clay minerals, sericite, and calcite, whereas hornblende and biotite are replaced by chlorite.
A distinct feature of these rocks is the red coloration caused by a pervasive regional hydrothermal alteration to sericite and limonite.Abundant microfractures and some mineral cleavages (feldspar and hornblende) are filled with an association of quartz + sericite + epidote + sulfides (pyrite and chalcopyrite), and calcite.

Juruena Complex
The Juruena Complex (Ribeiro and Duarte 2010), also known as Deformed Domain (Pinho et al. 2003), occurs in tectonic contact with the Volcanic Domain along a mylonitized corridor approximately 10 km wide as a result of conjugate transpressional sinistral shear zones.This set of faults apparently caused the exhumation of the Juruena Complex rocks to shallower crustal levels (Ribeiro and Duarte 2010).
The lithostratigraphic units that form the Juruena Complex in the study area are the Vitória Plutonic Suite, and the São Pedro Granite.These units have zircon U-Pb crystallization ages and depleted mantle Sm-Nd model ages around 1775 Ma and 2.0 Ga, respectively, and slightly negative and positive  Nd values (Duarte et al. 2012).They also share major, and trace element signatures, including rare earth elements (REE) that, combined with radiometric isotopic data, indicate a common petrogenetic origin (Ribeiro and Duarte 2010).
Macroscopic features mostly observed in these rocks are of protomylonite texture and gneissic layering.In addition, incomplete magma mixing and mingling features are common, such as elongate dioritic enclaves.Under the microscope, we observed oriented textures indicative of ductile deformation, including predominantly mylonitic, lepidoblastic, nematoblastic and porphyroclastic.In less deformed samples, granular and porphyritic textures are preserved.The mineralogy consists of quartz, plagioclase, hornblende, biotite, and microcline.Accessory minerals are apatite, epidote, magnetite, titanite, rutile, zircon and allanite.

São Pedro Granite
The São Pedro Granite is composed of metamonzogranite and metasyenogranite.Similarly to rocks of the Vitória Plutonic Suite, these rocks have an ellipsoidal shape and complex and diffuse contacts that resulted from ductile deformation and gradational contacts with other units.
In hand specimens, the granites have foliated protomylonitic and porphyroclastic textures, with quartz ribbons and oriented mafic minerals.The less deformed rocks are medium-to coarsegrained, and have hypidiomorphic-granular to porphyritic textures.Under the microscope, we observed granolepidoblastic and porphyroclastic to mylonitic textures, exhibiting undulose extinction and subgrains in quartz tracks and sub-grains.The porphyroclasts are of deformed perthitic K-feldspar and plagioclase embedded in a groundmass consisting of lamellar quartz, biotite, and oriented hornblende crystals.The primary mineral assemblage is quartz, plagioclase, K-feldspar, biotite, and hornblende; accessory minerals are magnetite, titanite, rutile, garnet, apatite, allanite, and zircon.

Previous U-Pb (zircon) crystallization ages
In the vicinity of the study area, various works applied zircon U-Pb geochronological analyses to support lithostratigraphic and geodynamic evolutionary hypotheses and interpretations for the SW Amazon Craton (Santos et al. 2000;JICA/MMAJ 2000, 2001;Neder et al. 2002;Pinho et al. 2003;Souza et al. 2005

Geochemistry
The selected rock samples were crushed in an agate disc mill to a 150-mesh at the laboratory facility of the CPRM -Geological Survey of Brazil, and analyzed by the SGS-Geosol laboratory.The powdered samples were then mixed with lithium metaborate and tetraborate, and melted through induction furnace at 1832° Fahrenheit.The resulting glassy tablets were dissolved in a 5% HNO3 solution containing a laboratory internal standard, and mixed until complete dissolution.The major oxide elements were analyzed by x-ray fluorescence (XRF); in turn, the REE and trace elements were analyzed by inductively coupled plasmamass spectrometry (ICP-MS), and FeO via gravimetric method.Rare Earth Elements (REE) values are normalized to chondrite (Nakamura 1974).Eu/Eu* = Eu N /(Sm N X Gd N ) (1/2) , magnesium number #mg = molar and FeO t = FeO + Fe 2 O 3 .Major elements are in wt.%, and trace elements in ppm (detection limit, D. L.).Analytical results were plotted on classification and tectono-magmatic discrimination diagrams using the GCDKit v.3.0 software (Janousek et al. 2006).

U-Pb LA-ICPMS
The procedure for concentrating zircon crystals followed the steps of sample crushing and then selecting the fractions thinner than 500 µm that were panned to recover a heavymineral concentrate.Next, the concentrate was passed through the Frantz isodynamic separator, and finally zircon grains were handpicked under a binocular microscope.The grains were mounted in cold epoxy resin, ground and polished to reveal their internal surfaces.The mounts were cleaned with 3% nitric acid, as well as cleaned ultrasonically with Nanopure® water, and acetone for the extraction of any moist residue.Analyses were conducted using a Multicollector Inductively Coupled Plasma Mass Spectrometer MC-ICP-MS Neptune (Thermo-Finnigan) coupled with the Nd:YAG (l = 213 nm) Laser Ablation System (New Wave Research, USA), at the Brasília University, Brazil.The analytical procedure was described by Bühn et al. (2009) and consists of ablation of crystals with spots 25 to 40 µm of diameter using a laser of 9 to 13 Hz, and fluence of 0.19 to 1.02 J/cm2.The powdered material is carried by He and Ar at flow rates of ~ 0.40 L/ min, and ~ 0.90 L/min, respectively.All sample analyses were performed using the international standard GJ-1 for standard-sample bracketing, and the TEMORA or internal standard PAD-1 for accuracy.Data acquisition occurred in 40 cycles of 1 second with a reading sequence of 1 blank, 1 standard, 4 samples, 1 blank, and 1 standard.The mass intensities of 202 Hg, 204 (Pb+Hg), 206 Pb, 207 Pb, 208 Pb and 238 U were determined for each reading.The raw data were reduced using an Excel worksheet of the laboratory, including blank corrections, standard deviation and common lead.All ratio uncertainties are at the 1- level.Age calculations were carried out using Isoplot 3.00 (Ludwig 2009).

Sm-Nd
The Sm-Nd isotopic analyses followed the methodology described by Gióia and Pimentel (2000).According to this procedure, approximately 50 mg of powdered sample is spiked with a 149 Sm-150 Nd tracer solution.The sample is then dissolved into Savillex® capsules through successive HF, HNO 3 , and HCl attacks.The Sm and Nd concentrations are determined using cationic exchange columns made of Teflon, and filled with LN-Spec resin.The Sm and Nd salts are deposited in rhenium filaments containing nitric acid followed by evaporation.Isotopic ratios were measured in a static mode using a multi-collector mass spectrometer, model Finnigan MAT 262 at the Brasília University, Brazil.Uncertainties in the 147 Sm/ 144 Nd and 143 Na/ 144 Nd ratios are less than ± 0.55 (2) and ± 0.0055 (2), respectively, based on repeated analyses of the international standards BHVO-1 and BCR-1. 143Nd/ 144 Nd ratios are normalized to 146 Nd/ 144 Nd= 0.7219.T DM values were calculated using the DePaolo (1981) model for the depleted mantle.

Geochemistry of the Volcanic Domain
The geochemical datasheet from the Volcanic Domain samples are presented in the Appendix A. The samples were grouped into Colíder Group volcaniclastic and basic to acid effusive volcanic rocks, and into Paranaíta Intrusive Suite granites based on textural aspects.After this step, the samples were geochemically classified using the De la Roche et al. (1980) R1-R2 diagram (Fig. 3).
Both the Colíder Group and the Paranaíta Intrusive Suite show calc-alkaline to mostly high-K calc-alkaline affinity (Fig. 4a), and span the entire compositional range from basalt to rhyolite.The intermediate to basic rocks are metaluminous, and the felsic rocks are peraluminous and metaluminous (Fig. 4b).FIGURE 4 -SiO 2 versus K 2 O diagram of Peccerillo and Taylor (1976); and (b) Alumina saturation index Al 2 O 3 /Na 2 O+K2O Maniar and Piccoli (1989).(Fig. 6c) of the basic rocks from the Colíder Group show a very slight fractionation of light REE relative to heavy REE, and a little pronounced compositional gap between basalts and andesites that are more differentiated.The primitive mantle normalized spidergram (Fig. 6f) also exhibit differences between these rocks mainly regarding the distribution pattern of high field strength elements (HFSE).Conversely, both are enriched in large ion lithophile elements (LILE) relative to HFSE, and show well-defined Nb and Ti negative anomalies similar to those of spidergrams for acid rocks.
In order to discriminate the tectonic setting of the Volcanic Domain, the samples were plotted in the Ta/Yb versus Th/ Yb diagram (Fig. 7) which has shown to be useful for allowing distinguishing subduction-related types from mantle-derived types (Pearce 1982).The results plot in the active continental margin area and show a distribution similar to that observed for the rocks of the Central Andes.
The Dall´Agnol and Oliveira ( 2007) diagrams in Fig. 8 allow the distinction between Type A and calc-alkaline (Active Continental Margin) granites as well as between reduced and  oxidized granites.All samples plot in the Type A field (Fig. 8a  and b), although some samples of alkali granite, granodiorite, rhyodacite, granite and quartz monzonite plot outside the delimited fields.In addition, in Fig. 8 c and d, it is possible to observe that the majority of the samples plot in or adjacent to the oxidized A-type fields (in a region of interface between the calc-alkaline field), with exception of the more differentiated samples (alkali rhyolites and granites with high Fe*) which plotted in the reduced A-type granites field.

Geochronology
This work reports seven zircon U-Pb geochronological analyses and four whole-rock Sm-Nd analyses from the Volcanic Domain.Sample locations are presented in Table 2, and the isotopic results are shown in the Appendix B.

Paranaíta Intrusive Suite
Sample GR-001 (micromonzogranite).Cathodoluminescence (CL) images of zircon grains reveal simple oscillatory zoning and rarely re-equilibration zones (Fig. 9a).Two typical morphologies are observed.The predominant types have stubby and equant morphologies, {100} and {110}, with a length/width ratio of 1.5:1, and (y) axis size between 300 and 400 µm.The subordinate population is needle-shaped, {101}, with a length/width ratio of 5:1, and (y) axis size between 400 and 500 µm.Twenty-seven spots were made throughout the cores and rims of twenty-four zircons that differ from each other in their habits but still yielded a single 207 Pb/ 206 Pb age group ranging from 1815 to 1780 Ma.Except for pits Z7, Z11, Z18, and Z24 that show data dispersion, the other analyses were used to calculate an upper intercept age of 1793.4 ± 7.2 Ma (MSWD =1.4).An alternative calculation using the most concordant data yielded a concordia age of 1780.3 ± 4.5 Ma (MSWD =2.3) (Fig. 9b).The two ages overlap within analytical uncertainty, and both can be used to express the crystallization age of the analyzed granite.
Sample GR-001A is a porphyritic granite that occurs in contact with the microgranite GR-001.The zircons extracted from this sample are inclusion-rich and cracked.Backscattered electron (BSE) imaging of zircons reveals fine-scale and well-defined oscillatory zonation patterns; zircon overgrowth is not observed (Fig. 10a).The crystal morphology is typical of plutonic rocks cooled slowly, types {100} and {110}, with a length/width ratio of 2:1 and (y) axis size between 150 and 300 µm.Twenty-four analyses were made on twenty-four zircons.The regression of all analyses gives an upper intercept age of 1807.2 ± 8.2 Ma (MSWD = 1.3) (Fig. 10b), which is interpreted as the crystallization age for this sample.
Samples TD-T-050S and TD-T-050AM.These samples are of a porphyry granite and a micromonzogranite similar to the samples GR-001A and GR-001, respectively.The zircons from TD-T-050S are idiomorphic, cracked, resembling external deformation processes such as mylonitization (Wayne and Sinha 1988), and have a few mineral inclusions.The internal structure revealed by BSE imaging (Fig. 11a) is marked by finescale oscillatory and rare sector zoning.The morphologies are similar to those of zircons from plutonic rocks (stubby and equant), type {100}, with a length/width ratio of 1.5:1, and (y) axis between 150 and 250 µm.Among the twenty-four analyses, two were discarded due to high errors (Z22) and scattered behavior (Z12) (Table 13).The other results yielded 207 Pb/ 206 Pb ages ranging between 1844 and 1761 Ma, with a mean 207 Pb/ 206 Pb age of 1810 +7/-18 Ma (94.3% conf.), and an upper intercept age of 1801 ± 12 (MSWD = 1.6) (Fig. 11b).The upper intercept age is interpreted as the crystallization age.
In the sample TD-T-050AM the zircon crystals are idiomorphic to sub-idiomorphic with a simple combination of short prisms and bipyramidal terminations.They are commonly fractured and contain inclusions.It is possible to identify mainly fine-scale oscillatory zonation and rare radial fractures in BSE image (Fig. 12a).Even though this sample shows petrographic texture typical of subvolcanic rocks; needle-shaped zircons are not identified.Instead, the zircon morphology is more similar to that of plutonic granites (stubby and equant), such as the {100} type, with a length/width ratio of 1.5:5.1, and (y) axis between 50 and 100 µm.Twenty-four analyses were obtained and one was discarded due to high analytical errors (Z12).The other spots show consistent results yielding an upper intercept age of 1815 ± 10 Ma (MSWD =0.95).An alternative calculation using the most concordant data yielded a concordia age of 1812 ±5.2 Ma (MSWD =0.049) (Fig. 12b).The two ages overlap within analytical uncertainty and both can be used to express the crystallization age of the analyzed granite.

Colíder Group
The sample TD-T-063K is an ignimbrite composed of devitrified pumices, lithoclasts and glass shards.The zircons are short with a combination of prismatic and bipyramidal terminations, their morphology is equidimensional, types {100} and {211}, having a length/width ratio of 1.5:1, and (y) axis between 150 and 200 µm.BSE imaging (Fig. 13a) reveals large-scale oscillatory zoning.Semi-circular indentations are commonly observed in zircon rims as a result of magmatic resorption and are characteristic of pyroclastic rocks (Corfu et al. 2003).Among twenty-four U-Pb isotopic analyses, twentythree gave good quality of results and one discarded due to high analytical error (Z4).The results were used to calculate an upper intercept age of 1823 ±33 Ma (MSWD = 0.74).An alternative calculation using the most concordant data yielded a concordia age of 1812 ±12 Ma (MSWD =1.6) (Fig. 13b), which is interpreted as the crystallization age of this rock.
Sample TD-095 is a porphyritic rhyodacite showing granophyric texture.The bipyramidal zircons with shortprismatic shape are homogeneous, inclusion-rich and abundantly fractured.The morphology is equidimensional, nearly rounded types {100} and {211}, with a length/width ratio of 1.5:1, and (y) axis between 100 and 150 µm.The BSE image (Fig. 14a) reveals discrete and well-defined oscillatory zoning.Despite the more fractured condition, these zircons are similar to those of sample TD-T-063K, which exhibits magmatic resorption features.Among the twenty-four analyses, five of them with high-analytical errors were discarded (Z5, Z8, Z10, Z12, and Z19).The regression of seventeen analyses gave an upper intercept age of 1813 ± 12 Ma (MSWD = 0.99).Alternatively, the five most concordant results were used to calculate a concordia age of 1809 ±6.5 (MSWD =1.6) (Fig. 14b).The two ages overlap within analytical uncertainty and both can be used to express the crystallization age of the analyzed sample.Analyses of zircons Z2 and Z15 were also not used in the calculation.They resulted in the oldest 207 Pb/ 206 Pb ages in all analyzed samples; 1924 and 1966 Ma, respectively, and are probably inherited.
Sample TD-107 is an amphibolite from the Colíder Group.The zircons are small, fractured and contain inclusions.Their (y) axis are between 50 and 120 µm with a morphology that is equidimensional and rounded, types {100}, {211} and {101}, with a length/width ratio of 2:1 and 1:1.BSE image (Fig. 15a) reveals discrete oscillatory zoning.The less fractured crystals exhibit a homogeneous internal structure and darker extremities, resembling compositional variations instead of overgrowth.Parallel fractures observed in these zircons may be related to deformation due to rapid decompression during volcanic eruptions (Rudnick and Williams 1987), and concentric diffusion bands are also common.Probably due to the fracturing and alteration, six out of twenty-four spots analyzed were discarded because of the high analytical error and common lead content (Z3, Z12, Z14, Z17, Z18, and Z19).The remaining zircons were then used to calculate three distinct upper intercept ages, based on different 207    is related to inherited zircons.The second upper intercept age was obtained by the regression of eight 207 Pb/ 206 Pb ages around 1800 Ma, ordinarily obtained in the Colíder Group rocks.This regression resulted in an upper intercept age of 1781 ± 18 Ma (MSWD =3.3), which is considered as the crystallization age of this rock.The third and younger age was obtained by the regression of only three 207 Pb/ 206 Pb relative ages, around 1650 Ma, which resulted in an upper intercept age of 1679 ± 21 Ma (MSWD =2.6) (Fig. 15b) that could be the result of a geological event that induced Pb loss.

Sm-Nd results
Table 3 gathers the whole-rock Sm-Nd analyses as well as depleted mantle model ages, T DM , and  Nd calculations for rocks of the Colíder Group and Paranaíta Intrusive Suite.The T DM age for the acid rocks from the Colíder Group (TD-T-063K) is 1.9 Ga with a positive  Nd value of +2.05.The sample TD-R-107, representative of the basic to intermediate magmatism of the Colíder Group, yielded a T DM age of 2.2 Ga and  Nd value of +0.4, which is also consistent with the Sm-Nd isotopic signature of the Volcanic Domain magmatism.
The sample TD-T-050S from the Paranaíta Suite yielded the oldest T DM age of 2.4 Ga, and also a unique negative  Nd value in this dataset.Conversely, another sample from the Paranaíta Intrusive Suite (TD-T-050AM) yielded a younger T DM age and a slightly positive  Nd value (2.0 Ga and +0.68), respectively.
The diagram of  Nd evolution versus time (Fig. 16) was elaborated to enable the comparison between the present Sm-Nd results with the available Sm-Nd data results from the literature for the Volcanic Domain and Juruena Complex (Table 4).
The dataset gathered in Tables 3 and 4 and plotted in Figure 16 shows a broad interval of T DM ages ranging from 2.40 to 1.84 Ga and the  Nd(t) (t=1.8Ga) calculated for these samples vary from negative (-0.20 to -3.90) to positive (0.10 to 2.50) values.Note that the negative and positive  Nd(t) values are directly related to the oldest (2.4 to 2.1 Ga) and younger (2.0 a 1.9 Ga) T DM ages.The younger T DM ages with positive  Nd(t) values of the Colíder Group are related to the basic rocks.
The pattern of T DM ages and  Nd(t) values of the Juruena Complex (darker envelope) is very similar to that of the Volcanic Domain.The T DM age interval is of 370 Ma for 13 rock samples, between 2.30 and 1.93 Ga with a mean age of 2.07 Ga, and  Nd(t) values with (t=1.78Ga) vary from positive (0.26 to 2.10) to negative (-0.25 to -2.57).
A direct relationship between older and younger T DM ages related to negative and positive  Nd(t) values respectively is observed for the Volcanic Domain.Similarly, identical intervals of T DM ages and  Nd(t) values are found among the results for the Juruena Complex as follows: older interval (2.3 to 2.1 Ga with  Nd(t) -0.25 to -2.57), and younger interval (2.0 to 1.9 Ga with  Nd(t) 0.26 to 2.10).

Discussion
8.1 The relation among the Paranaíta-Colíder association with other volcano-plutonic units (Teles-Pires Intrusive Suite and Roosevelt Group).
In the southwestern Amazon Craton, the 1.8 Ga undeformed volcanic rocks and associated granites (Volcanic Domain) have been understood geologically in three different ways, as well, many distinct names have been proposed for the units.
For some authors (Neder et al. 2002;Pinho et al. 2003;Cordani andTeixeira 2007 and2009), the Volcanic Domain is the result of an intra-plate magmatism related to extensional structures developed at the SW border of the Ventuari-Tapajós Province, as well as related to the breakup of the supercontinent Columbia ( or NUNA).These authors consider this volcano-plutonism as part of the Teles-Pires magmatism, and yield crystallization ages for these rocks ranging from 1800 to 1776 Ma (Pinho et al. 2003;Cordani and Teixeira 2007;Barros et al. 2009).Other authors (Santos et al. 2000 and2008;Souza et al. 2005;Ribeiro and Duarte 2010;Duarte et al. 2012;Scandolara et al. 2014) have understood the coeval (1.8 Ga) plutonic-volcanic event (Volcanic Domain) as a subduction-related continental arc magmatism of the Juruena Magmatic Arc, and attributed to the volcanic and plutonic rocks to the Colíder Group and to the Paranaíta Intrusive Suite, respectively (Fig. 17 Another example of widespread volcanism in the Juruena Magmatic Arc is the volcano-sedimentary sequence of the Roosevelt Group and the associated Aripuanã Granite (Neder et al. 2002;Santos et al. 2000;Rizzotto et al. 2002;Biondi et al. 2013).These rocks exhibit crystallization ages between 1762 and 1740 Ma (Fig. 17).Even though these rocks are 30 to 40 Ma younger than the Teles-Pires magmatism,   2013) also have described Pb-Zn-Cu volcanic-hosted massive sulfide deposits for the Roosevelt Group that are very distinct from the Au epithermal-porphyry systems found within the Volcanic Domain.
The cross-section presented in Figure 18 shows the arrangement of the Juruena Magmatic Arc geology according to a continental magmatic arc tectonic evolution.In this model, the precursor magmas are related to subduction processes and hydrous melting of the SCLM plus the assimilation and reworking (AFC processes) of a Ventuari-Tapajós crust.The products   are the basic to intermediate rocks as well as the oxidized A-type granitic rocks from the Volcanic Domain, including its volcanic counterparts.In addition, the deeper emplaced calcalkaline rocks of the Juruena Complex were also generated (Phase 1).The same figure illustrates the relationship between the Volcanic Domain with the other volcanic-plutonic units (Roosevelt Group and Teles-Pires Suite), which developed in a more mature period of the arc (<1780 Ma), reflecting changes in the tectonic regime with the establishment of forearc and backarc type tectonic environments (Phase 2).
Santos et al. 2019 also recognize two magmatic events in the Colíder Group based on slightly different geochemical signatures and U-Pb geochronology.The first one around 1.80 Ga (lower succession), dominantly magnesian, and the second one around 1.76 Ga (upper succession), dominantly ferroan and with more pronounced Eu, Sr and P negative anomalies.

Geodynamic setting of the Volcanic Domain based on the geochemistry
Although the use of granites as geodynamic indicators in some cases has shown to be inappropriate, careful combination of the methodology proposed by Barbarin (1999) with geochronological data usually succeeds in solving geotectonic issues.
High-K calc-alkaline magma series along with an alumina saturation index, which varies from metaluminous to peraluminous, suggests a mixed crustal-mantle source for the magmatism of the Volcanic Domain prevailing the crustal component (Barbarin 1999).Even though some monzogranites and granodiorites from the Paranaíta Intrusive Suite have amphibole, these rocks are potassium-rich and, therefore, classified as K-rich calc-alkaline granitoids (KCG).The volcanic rocks from the Colíder Group (mainly rhyodacite), the less differentiated varieties (regarding SiO 2 contents), with lower K 2 O and higher CaO, MgO and Fe 2 O 3 contents also belong to the high-K calc-alkaline series.
The REE spectrum with enrichment in light REE relative to heavy REE and negative Eu anomalies are similar to that of high fractioned high-K calc-alkaline magmas.The Harker's diagrams and trace element patterns show well-defined Nb, P and Ti negative anomalies, suggesting a magmatic evolution dominated by fractional crystallization of plagioclase, minerals containing Mg-Fe (pyroxene, hornblende and biotite), apatite and Ti-magnetite (Fig. 5 and 6), and implying contamination of the source by subduction of continental crust (Wilson 1989).Samples from the Volcanic Domain plot in the active continental margin field in tectonic-magmatic discrimination diagram (Fig. 7) (Pearce et al. 1984), a behavior that is similar to that observed for the Central Andes.
Conversely, in the major elements diagrams the acid rocks samples plot in the A-type oxidized and reduced field (Fig. 8).Thus, the hypothesis of more differentiated A-type reduced granitic rocks from the Volcanic Domain as result of extensional tectonics in the Juruena Magmatic Arc is plausible.
Also, taking into account the discussion above, it is not possible to confirm a major presence of amphibole-bearing calc-alkaline granitoids (ACG) in the Volcanic Domain that is supposed to prevail in continental magmatic arc subductionrelated settings.A hypothesis is that most of these intermediate rocks are probably covered by the volcaniclastic deposits.
However, it is necessary to understand the Volcanic Domain in the context of the Juruena Magmatic Arc evolution.The Vitória Plutonic Suite and the Vespor Suite (Scandolara et al. 2014), which contain typical arc-related rocks such as calc-alkaline metagabbros, metadiorites, metatonalites, and metagranodiorites, best fit what is expected to be found in continental arc settings in association with KCG granitoids.Highly metamorphosed sediments and remnants of oceanic crust belonging to the Bacaeri-Mogno Complex accreted to the arc are also identified and reinforce the hypothesis that the Volcanic Domain in the Juruena Complex is related to a continental arc.

The volcano-plutonic association of the Volcanic Domain as part of the Juruena Magmatic Arc
The integration of the Volcanic Domain to the Juruena Complex discussed above in the context of the Juruena Magmatic Arc is based on depleted mantle model ages,  Nd values and zircon U-Pb crystallization ages.
Among twenty analyses carried out on samples from the Volcanic Domain, T DM ages range from 2.40 to 1.84 Ga, and the calculated  Nd (t=1.8)values for the same samples vary between negative (-0.20 to -3.90) and positive (+0.10 to +2.50).The results from the T DM dataset of the Juruena Complex are very similar, with T DM ages ranging between 2.30 and 1.93 Ga, and  Nd (t=1.78)values also ranging between negative (-0.25 to -2.57) and positive (+0.26 to +2.10).
These two T DM age intervals with distinct  Nd values indicate heterogeneous magma sources.Although apparently, the older T DM ages from 2.3 to 2.1 Ga, and negative  Nd(t) values (around -1.5) are compatible with a continental crust source, they could represent a more fractioned source.Conversely, the younger source with T DM ages varying between 2.0 and 1.9 Ga, and positive  Nd(t) values (around +1.0) suggests a less differentiated and juvenile source.
The older source has T DM ages compatible with the crystallization ages from the Orosirian magmatic episodes of the Erepecuru-Trombetas and Irirí-Xingu Domain (Leal et al. 2018); in turn, the younger (more juvenile) source have T DM ages similar to the crystallization ages of the Ventuari-Tapajós Province formation stage (Cuiú-Cuiú -island arc; Creporizão -continental arc; Tropas -island arc/continental arc) (Santos et al. 2004).
The zircon U-Pb crystallization ages obtained in this work for the Volcanic Domain are comparatively homogeneous showing the following results: Paranaíta Intrusive Suite (from 1815 ± 10 to 1780 ± 5 Ma), and Colíder Group (from 1813 ± 12 to 1781 ± 18 Ma).The overlap of these ages indicates that the volcanism and the plutonism are coeval (Fig. 19).
Another observation is the presence of inherited or premagmatic zircons in the Volcanic Domain samples TD-095 and TD-107 were 207 Pb/ 206 Pb relative ages around 1950 Ma and 1870 Ma respectively are present in the results.These ages around 1950 Ma and 1870 are common within the rocks from Creporizão or Nhandú and Maloquinha or Matupá Intrusive Suites from the Ventuari-Tapajós Province and so are probably related to that basement inlier.Miller et al. (2003) describe such inheritance-poor granitoids as "hot" (crystallization above 800 °C) rocks, which are generated by current well-known magmatic processes (dehydration-melting in the crust; fractionation of mantle melts, with or without crustal contamination), including the transport of crystal-poor and highly eruptible magma.On the other hand, "cold" inheritance-rich granitic intrusions (crystallization below 800 °C) are usually crust-derived, as well as crystal-rich and unlikely to erupt.
The younger upper intercept age of 1679 ± 20 obtained for the sample TD-107 (amphibolite) is an issue to be studied in this undeformed rock that does not show metamorphic overgrowths in the zircons crystals.Thus, this age may be only related to some sort of Pb loss during this time.However, it is valid to mention that to the west of the area, metamorphic ages around 1640 Ma (zircon overgrowth rims) were obtained in rocks of highly deformed granulite facies from Jamari Complex and thus they are related to the collisional orogeny Quatro Cachoeiras (Rizzotto et al. 2004;Santos et al. 2008).Also Pinho et al. (2003) and Lacerda Filho (2004) obtained within the Juruena Complex (Vitória Suite tonalite gneiss), very close to the study area, zircon Pb-Pb and U-Pb ages around 1660 Ma that were interpreted as related to the collisional orogeny mentioned above.
Another alternative is that these younger zircon apparent ages could represent the crystallization time, although ages around 1700 Ma (even K-Ar or Ar-Ar) are absent in the Ventuari-Tapajós and Rio Negro-Juruena Provinces.
Volcanic and plutonic rocks often occur in similar geodynamic settings.Examples include the Andes (De Silva et al. 2006), the San Juan volcanic field in Colorado (Lipman 2007) and the Colorado River region to the south of Nevada and Arizona (Metcalf 2004) were the volcano-plutonic association is directly observed in places where the volcanic cover has been eroded, thus exposing the upper parts of cogenetic intrusions (Bachmann et al. 2007).
A Paleoproterozoic example described in the Ventuari-Tapajós Province (Santos et al. 2004) includes the Iriri intermediate to acid volcanic sequence that is associated with late-orogenic to post-collisional granitic intrusions.Juliani et al. (2005) have identified high-sulfidation epithermal gold deposits in the same region related to large caldera complexes and epizonal porphyry intrusion domes, an analogous framework to that observed in the Volcanic Domain.
The interpretation of late-orogenic to post-collisional tectonic settings, proposed by Barros et al. (2009), Alves et al. (2013) and Silva et al. (2014), also supports the Volcanic Domain as high-K calc-alkaline magmatism.However, in order to consider this hypothesis, the oldest crystallization ages obtained for the Juruena Magmatic Arc must be discarded.Indeed, this implies that the Volcanic Domain is not related to the Juruena Complex and therefore, the Volcanic Domain should be classified as a Terrane.
The hypothesis of Volcanic Domain be a Terrane is impracticable due to field relationships, lithogeochemical similarities, Sm-Nd data, and U-Pb dataset, which point to the integration of the Volcanic Domain with the Juruena Complex.As shown in Fig. 20, the crystallization ages of the Juruena Complex, which is interpreted to be a calc-alkaline synorogenic continental arc magmatism (1787 ± 14 to 1755 Ma), are overlapping with those from the Volcanic Domain.  1 and 2.

Mafic Magmatism in the southwestern Amazon Craton and geodynamic implications for the Columbia (or NUNA) Supercontinent
The mafic rocks cropping out in the study area are correlated to the Colíder Group magmatism.An amphibolite sample analyzed via U-Pb (zircon) and Sm-Nd yielded a crystallization age of 1781 ±18 Ma and a T DM age of 2.2 Ga with  Nd(t=1.8)value of + 0.4.Pinho et al. (2003) also obtained U-Pb (zircon) ages within that age interval for two mafic samples collected from around the survey area: 1797 ± 5 Ma (mafic tuff), and 1776 ± 3 Ma (basalt).Santos et al. (2002) established five mafic magmatic events for the Ventuari-Tapajós Province by using a considerable dataset of U-Pb (baddeleyite and zircon) analyses from mafic rocks cropping out to the north of the area.The oldest stocks and dikes with ages around 1893 Ma are called Ingarana and they are related to orogeny.The other dikes, all related to distinct extensional anorogenic periods, show ages around 1780 Ma, 1180 Ma, and 500 Ma.These are called Crepori, Cachoeira Seca, and Piranhas, respectively, while a younger set of dikes, with ages in the interval between 260 Ma to 120 Ma, are named Periquito.Among all dikes analyzed, the Crepori has been of great importance to this study with ages correlating with the mafic magmatism of the Colíder Group.Santos et al. (2002) observed that ages around 1780 Ma are linked to mafic intrusions in the Amazon and La Plata Cratons.Examples include the Avanavero magmatism in northern Amazon Craton (1778 ± 12 Ma) (Reis et al. 2013), and Tumatumari in Guiana (1786 ± 5 Ma) (Norcross et al. 2000) and Piedra Alta Terranes (1785 ± 4 Ma) (Hall et al. 2001;Teixeira et al. 2010) in the La Plata Craton.Santos et al. (2002) stated that these intrusions define an N-S alignment that corresponds to the western border of the Columbia (NUNA) supercontinent and its breakup (Rogers 1996), taking into account that worldwide large volumes of mafic magmatism at the end of the Paleoproterozoic are related to this supercontinent disassembly.Scandolara et al. (2014) studied the Vespor Suite, the mafic lithostratigraphic unit in the Juruena Complex, based on lithogeochemistry and geochronology.The samples, which yielded U-Pb ages of 1773 ± 15 Ma (gabbronorite) and 1764 ± 14 Ma (gabbro), belong to the tholeiitic magma series, and have chemical signature typical of continental arc settings; the magma derived from a source that is a mixture of metasomatic oceanic crust and crustal components.Based on these results, Scandolara et al. (2014) interpreted the SW border of the Amazon Craton (Juruena Magmatic Arc) to be developed along an oceanic trench with subduction of oceanic crust under a passive continental margin (Central Amazonian and Ventuari-Tapajós Provinces) at the beginning of the Paleoproterozoic.
Several continental arcs of 1.8-1.7 Ga are recognized worldwide (Rogers andSantosh 2002 and2004;Zhang et al. 2012) and they are considered as products of continental arc amalgamations over the Paleoproterozoic (2.0 to 1.8 Ga) that culminated in the assembly of the Columbia supercontinent (or NUNA) (Hoffman 1989;Roger andSantosh 2002, 2004;Zhao et al. 2004).Scandolara et al. (2014) based on the proposed continental arc geodynamic setting for the Juruena Magmatic Arc, with ages between 1.8 and 1.74 Ga, suggested that the period of Columbia (NUNA) amalgamation must be revised and extended until around 1.74 Ga.Bispo-Santos et al. (2012) have also proposed that the period of Columbia amalgamation should be extended for this sector and the taphrogenesis period revised with basis on paleomagnetic data and biotite Ar-Ar ages (1420 Ma) from a set of mafic dikes (Nova Guarita Intrusive Mafics) at the Peixoto de Azevedo Region, extreme east of the Volcanic Domain.

Conclusions
The Colíder Group and the Paranaíta Intrusive Suite form a plutonic-volcanic association whose eruptions from ~1815 to 1780 Ma gave rise to the Juruena Magmatic Arc Volcanic Domain.
The predominance of rocks with high-K calc-alkaline A-type (oxidized and reduced) chemical signatures suggests that the magmatism in the Volcanic Domain is from distal geodynamic settings in relation to a stable continental platform (Ventuari-Tapajós Province).As a result, it has been usually associated with the (1) Columbia supercontinent (NUNA) disassembly at 1.8 Ga, or (2) Juruena Magmatic Arc late-to post-orogenic stages.However, both models show contradictions: (1) Assuming the Columbia Supercontinent (or NUNA) taphrogenesis, it would be expected to identify rocks with crystallization ages of the displaced block (Ventuari-Tapajós) to the west/southwest of the Volcanic Domain.In addition, recent works based on geochronology and paleomagnetism of the dike swarms shows that in the Amazon Craton the Columbia supercontinent (NUNA) disassembly was after 1.8 Ga.
(2) The crystallization ages obtained for the Volcanic Domain include the older ages of the Juruena Magmatic Arc and, therefore, part of these rocks cannot be related to the late-orogenic or post-collisional magmatism stage in relation to this arc.
Based on the data presented here, it is more adequate to consider the basalts, andesites and less differentiated oxidized A-type granitic rocks of the Volcanic Domain as part of the Juruena Magmatic Arc volcanic belt and to correlate the more differentiated and reduced A-type rocks to the back-arc Teles-Pires magmatism or forearc Roosevelt magmatism.This set of granitic rocks alone, with A-type signatures, is showing variations in the tectonic regime throughout the time interval of 1815 to 1780 Ma instead of a specific geodynamic setting.
The maintenance of a continental arc-related interpretation for part of the Volcanic Domain magmatism is based upon its spatial arrangement, the volume of acid volcaniclastic deposits and associated epizonal granite intrusions, T DM age intervals and  Nd values similar to the rocks from the Juruena Magmatic Arc (Juruena Complex and Volcanic Domain), presence of oceanic crust remnants from the Bacaeri-Mógno Complex and by the synplutonic epithermal-porphyry gold systems along the Alta Floresta Gold Province.Also, the REE and trace-element chemical signatures of basic to acid rocks from the Volcanic Domain are also indicative of the continental arc related geodynamic setting, because they show the influence of an enriched SCLM source in subduction zone fluids and crustal contamination.
In addition, the older source with T DM ages between 2.3 and 2.1 Ga and negative  Nd values (~ -1.5), and a younger, more juvenile source, with T DM ages between 2.0 and 1.9 Ga and positive  Nd values (~ +1.0) are indicative of a mixed magmatic source with contribution of crustal materials (subducted sediments) and mantle, resulting in these distinct Sm-Nd isotopic signatures.

FIGURE 2 -
FIGURE 2 -Geotectonic map of part of the SW Amazon Craton highlighting the lithostratigraphic units that composes the Juruena Magmatic Arc, basement fragments of Tapajós-Parima Province at east, anorogenic granites from Serra da Providência Suite and sedimentary basins (modified from Ribeiro and Duarte 2010).

FIGURE 3 -
FIGURE 3 -De la Roche et al. (1980) R1-R2 diagrams used for the classification of rock samples from the Colíder Group volcanics (a) and Paranaíta Suite (b).

FIGURE 5 -
FIGURE 5 -Major-and trace-element Harker's variation diagrams of rocks from the Colíder Group and Paranaíta Intrusive Suite.

FIGURE 8 -
FIGURE 8 -Granite classification diagrams using major element concentrations for the acid rocks from the Volcanic Domain Dall`Agnol and Oliveira (2007).In (a) and (b) diagrams with the compositional fields of A-type and calc-alkaline granites.In (c) and (d) diagrams with the compositional fields of A-type reduced, oxidized and calc-alkaline granites.

FIGURE 9 -
FIGURE 9 -(a) Cathodoluminescence image of zircons of a microgranite from the Paranaíta Intrusive Suite (sample GR-001) showing morphological features and location of pits; (b) U-Pb upper intercept age in the concordia diagram and the 207 Pb/ 206 Pb age of the two crystals aging around 1840 Ma.The blue color represent the spots results used in the upper intercept calculation, conversely, the red color represent those not used.

FIGURE 11 -
FIGURE 11 -(a) BSE image of zircons of a porphyritic granite from the Paranaíta Intrusive Suite (sample GR-001A) showing their morphological features, location and ID of pits; (b) U-Pb concordia diagram for GR-001A.

FIGURE 13 -
FIGURE 13 -(a) BSE image of zircons of a volcaniclastic from the Colíder Group (sample TD-T-063K) showing their morphological features, location and ID of pits; and (b) U-Pb upper intercept age in the concordia diagram.The blue color represent the spots results used in the upper intercept and concordia age calculation, conversely, the red color represent those not used.

FIGURE 14 -
FIGURE 14 -(a) BSE image of zircons of a rhyodacite (sample TD-095) from the Colíder Group showing their morphological features, location and ID of pits; and (b) U-Pb concordia diagram and the upper intercept age calculated including the ages related to inherited zircons.

FIGURE 15 -
FIGURE 15 -(a) BSE image of zircons of an amphibolite (sample TD-107) from the Colíder Group showing the morphological features, location and ID of pits; and (b) U-Pb concordia diagram and the upper intercept age calculated.The spots marked in blue, brown and yellow were used in the calculations of the middle, younger and older upper intercept ages respectively.The spots marked with red number were not used in the calculations.
).More recently,Barros et al. (2009),Alves et al. (2013) andSilva et al. (2014) have interpreted similar rocks as related to a late-to post-tectonic extensional back-arc environment in relation to the Juruena Magmatic Arc evolution.Alves et al. (2013) dated A-type volcanic rocks at 1792 Ma and associated granites at 1775 Ma (Pium Granite) assigning these rocks to the Teles-Pires magmatism.

FIGURE 16 -
FIGURE 16-Nd-isotope evolution diagram of the Volcanic Domain and Juruena Complex.The solid green lines are from the present whole rock Sm-Nd analyses results.The grey areas envelope the bibliography whole rock eNd results from Volcanic Domain and Juruena Complex.The  Nd(t) values were recalculated for t=1.8 Ga.Depleted Mantle (DM); Chondritic Uniform Reservoir (CHUR).Depleted mantle model (De Paolo 1981).Chondrite present day values 147 Sm/ 144 Nd=0.1967 and 143 Nd/ 144 Nd=0.512636. 147Sm Decay constant=6.54x10-12.

FIGURE 18 -
FIGURE 18 -Cross section scheme of tectonic evolution of the Juruena Magmatic Arc showing the arrangement of the discussed geological units within a proposal of magmatism in two phases related to subduction and extensional character.
; Silva and Abram 2008; Ribeiro and Duarte 2010; Alves et al. 2013; Serrato et al. 2014 and Santos et al. 2019).The results available for units of the Volcanic Domain and the Juruena Complex are shown in Table 1.

TABLE 1 -
U-Pb (zircon) isotopic dating results and crystallization ages for the Volcanic Domain and Juruena Complex (Vitória Plutonic Suite and São Pedro Granite) (dataset from bibliography).

TABLE 2 -
Information about the analyzed samples.Geographic coordinates in decimal degrees (WGS84).
Pb/ 206 Pb age populations.The regression of the seven oldest 207 Pb/ 206 Pb relative ages resulted in an upper intercept age of 1852 ± 15 Ma (MSWD =0.72).This age

TABLE 3 -
Whole rock Sm-Nd analyses of the Volcanic Domain.

TABLE 4 -
Whole rock Sm-Nd results from the bibliography used in the construction of the Nd-isotope evolution diagram presented in Figure16.
Neder et al. (2002)a (2007)lcanic Domain trend,Pinho et al. (2003)andCordani and Teixeira (2007)correlate these rocks to the Teles-Pires magmatism.However, other works that take into consideration the crystallization ages and occurrence pattern of the Roosevelt Group have interpreted this unit to be developed in a retro-arc setting in relation to the Juruena Magmatic Arc Evolution.In addition to the younger crystallization age range,Neder et al. (2002)andBiondi et  al. (

206 Pb / 204 Pb 207 Pb/ 206 Pb Error (%) / 1 207 Pb / 235 U Error (%) / 1 206 Pb / 238 U Error (%) / 1 Rho
APPENDIX A1 -Major and trace element contents of acid effusive rocks from the Colíder Group.(cont.)Majorand trace element contents of volcaniclastic rocks from the Colíder Group.(cont.)Majorand trace element contents of samples from the Paranaíta Intrusive Suite.(cont.)Majorand trace element contents of samples from the Paranaíta Intrusive Suite.(cont.)Majorand trace element contents of intermediate to basic rocks from the Colíder Group.U-Pb LA-ICP-MS data for microgranite GR-001 from the Paranaíta Intrusive Suite.(cont.)Thef206(%) column shows the percentage of 206 Pb that is common lead.Common lead corrected using the 206 Pb/ 204 Pb ratio.Conc.(%)corresponds to the level of concordance of the analyses.APPENDIX B2 -U-Pb LA-ICP-MS data for porphyry granite GR-001A from the Paranaíta Intrusive Suite.(cont.)APPENDIXB3 -U-Pb LA-ICP-MS data for porphyry granite TD-T-050S from the Paranaíta Intrusive Suite.(cont.)Thef206(%) column shows the percentage of 206 Pb that is common lead.Common lead is corrected using the measured 206 Pb/ 204 Pb ratio.Conc.(%)corresponds to the level of concordance of the analyses.APPENDIX B4 -U-Pb LA-ICP-MS data for microgranite TD-T-050AM from the Paranaíta Intrusive Suite.(cont.)Thef206(%) column shows the percentage of 206 Pb that is common lead.Common lead is corrected using the measured 206 Pb/ 204 Pb ratio.Conc.(%)corresponds to the level of concordance of the analyses.APPENDIX B6 -U-Pb LA-ICP-MS data for granophyric rhyodacite TD-095 from the Colíder Group.(cont.) DL: Detection Limit Major elements in wt.%; Trace elements in ppm APPENDIX A2 -DL: Detection Limit Major elements in wt.%; Trace elements in ppm APPENDIX A3 -DL: Detection Limit Major elements in wt.%; Trace elements in ppm Notes: The f206(%) column shows the percentage of 206 Pb that is common lead.Common lead is corrected using the 206 Pb/ 204 Pb ratio.Conc.(%)corresponds to the level of concordance of the analyses.APPENDIX B1 -