Abstract The Pelotas Batholith forms the eastern portion of the Neoproterozoic Dom Feliciano Belt and records the final stages of the Neoproterozoic Brazilian–Pan-African orogeny. This granite-dominated belt experienced a complex tectonomagmatic evolution, yet constraints on the nature, and especially, the timing of the different magmatic stages are still scarce. This study provides new geochemical and geochronological constraints on the Grupelli Granite, a post-deformational pluton located in the rural district of Quilombo, Pelotas, RS. This granite crops out as a series of sub-kilometric solid bodies along a NE–oriented fault zone, intruding the Pinheiro Machado Complex that dominates the central and southeastern portion of the Pelotas Batholith. The studied granite is widely used as an ornamental rock due to its extremely leucocratic and isotropic appearance. The Grupelli Granite is homogeneous, relatively undeformed, inequigranular and typically medium-to coarse-grained (1–5 mm), with porphyritic and hypidiomorphic textures. Based on modal mineralogy the rock is a monzogranite with 40–50% quartz, 19–25% K-feldspar, and 15% oligoclase, 3–5% biotite, 2–3% magnetite and ilmenite, and accessory chlorite, zircon, apatite, chalcopyrite, and pyrite. Geochemically, the Grupelli Granite is characterized by high SiO2 (74–77 wt%) and K2O (5.08–5.65 wt%) contents combined with low FeOt (1.71–1.93 wt%), MgO and TiO2 (

中文翻译：

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Grupelli 花岗岩的地球化学和 U-Pb (SHRIMP) 年代学：对 Dom Feliciano 带 Pelotas Batholith 中长英质岩浆作用停止的新限制

摘要 Pelotas 基石形成了新元古代Dom Feliciano 带的东部，记录了新元古代巴西-泛非造山运动的最后阶段。这条以花岗岩为主的带经历了复杂的构造岩浆演化，但受自然条件的制约，特别是不同岩浆阶段的时间性仍然缺乏。这项研究为 Grupelli 花岗岩提供了新的地球化学和地质年代学约束，Grupelli 花岗岩是位于 RS Pelotas 的 Quilombo 农村地区的变形后岩体。这块花岗岩沿着东北向的断层带以一系列亚千米级固体形式出现，侵入了在 Pelotas 基岩中部和东南部占主导地位的 Pinheiro Machado 复合体。所研究的花岗岩由于其极其白化和各向同性的外观而被广泛用作观赏岩石。Grupelli 花岗岩是均质的、相对未变形的、不等粒的，通常为中到粗粒（1-5 毫米），具有斑状和双形纹理。根据模态矿物学，岩石是二长花岗岩，含有 40-50% 的石英、19-25% 的钾长石和 15% 的寡长石、3-5% 的黑云母、2-3% 的磁铁矿和钛铁矿，以及副绿泥石、锆石、磷灰石、黄铜矿和黄铁矿。在地球化学上，格鲁佩利花岗岩的特征是高 SiO2 (74–77 wt%) 和 K2O (5.08–5.65 wt%) 含量以及低 FeOt (1.71–1.93 wt%)、MgO 和 TiO2 ( 根据模态矿物学，岩石是二长花岗岩，含有 40-50% 的石英、19-25% 的钾长石和 15% 的寡长石、3-5% 的黑云母、2-3% 的磁铁矿和钛铁矿，以及副绿泥石、锆石、磷灰石、黄铜矿和黄铁矿。在地球化学上，格鲁佩利花岗岩的特征是高 SiO2 (74–77 wt%) 和 K2O (5.08–5.65 wt%) 含量以及低 FeOt (1.71–1.93 wt%)、MgO 和 TiO2 ( 根据模态矿物学，岩石是二长花岗岩，含有 40-50% 的石英、19-25% 的钾长石和 15% 的寡长石、3-5% 的黑云母、2-3% 的磁铁矿和钛铁矿，以及副绿泥石、锆石、磷灰石、黄铜矿和黄铁矿。在地球化学上，格鲁佩利花岗岩的特征是高 SiO2 (74–77 wt%) 和 K2O (5.08–5.65 wt%) 含量以及低 FeOt (1.71–1.93 wt%)、MgO 和 TiO2 (