Abstract New geological and geochronological (Pb-Pb evaporation) data from the Vila Jussara suite, a representative of the Neoarchean granitoids of the Carajas province, southeastern Amazonian craton (Brazil), are discussed. The Vila Jussara suite crops out as a series of coalescing plutons elongated in the E-W direction. These plutons generally have sigmoidal shapes, and steep dips (75–85°) that follow the regional trend. The centermost areas of plutons are generally slightly deformed, while the marginal portions display mylonitic aspect and are delimited by sinistral shear zones belonging to the transcurrent system of the Itacaiunas shear belt. These granitoids cover a large compositional spectrum, with four main lithotypes: (i) Seriated biotite-hornblende monzogranite; (ii) biotite-hornblende tonalite; (iii) porphyritic biotite monzogranite-granodiorite; and (iv) porphyritic hornblende-biotite monzogranite-granodiorite. The microstructural analysis of the studied rocks reveals: (i) microfractures in feldspar phenocrysts, filled with a quartz-feldspar matrix; (ii) preferred orientation of euhedral feldspar crystals in an igneous matrix; and (iii) evidence of moderate-to high-temperature of solid-state deformation (>500 °C). These microstructures and field observations point to a continuum of deformation, from the (sub) magmatic state down to sub-solidus conditions. Dating of three types of granitoids out of four gives ages of 2754 ± 2.2 Ma, 2752 ± 5.7 Ma and 2745 ± 3 Ma. The different granitoid varieties of the Vila Jussara suite were thus emplaced simultaneously. It is proposed that emplacement of the granitoids was controlled by shear zones reactivated during oblique collision and that plutons where constructed by multiple injections of magmas, generating extensive hybridization.

中文翻译：

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亚马逊克拉通东南部（巴西）卡拉哈斯省新太古代深成复合体侵位的岩性和结构控制

摘要 讨论了来自 Vila Jussara 组的新地质和地质年代学（Pb-Pb 蒸发）数据，该组是亚马逊克拉通东南部（巴西）Carajas 省新太古代花岗岩的代表。Vila Jussara 套房以一系列在 EW 方向拉长的聚结岩体形式出现。这些岩体通常具有 S 形形状，并且具有遵循区域趋势的陡倾角 (75–85°)。岩体的最中心区域通常轻微变形，而边缘部分显示糜棱面，并由属于 Itacaiunas 剪切带横流系统的左旋剪切带界定。这些花岗岩的组成范围很大，有四种主要的岩型： (i) 序列黑云母-角闪石二长花岗岩；(ii) 黑云母角闪石；(iii) 斑状黑云母二长花岗岩-花岗闪长岩；(iv) 斑状角闪石-黑云母二长花岗岩-花岗闪长岩。所研究岩石的微观结构分析表明：(i) 长石斑晶中的微裂缝，充满石英-长石基质；(ii) 火成岩基质中自形长石晶体的择优取向；(iii) 中高温固态变形的证据 (>500 °C)。这些微观结构和现场观察表明变形的连续统一体，从（亚）岩浆状态到亚固相状态。对四类花岗岩中的三类进行测年得出的年龄分别为 2754 ± 2.2 Ma、2752 ± 5.7 Ma 和 2745 ± 3 Ma。Vila Jussara 套房的不同花岗岩品种因此被同时安置。