Abstract The southern sector of the Paleoproterozoic Lourenco domain in the central-eastern region of the Amapa state, northern Brazil, consists mainly of Rhyacian granite-greenstone terranes with some Archean fragments. It is located at the transition with the Archean Amapa block, a Meso-Neoarchean continental landmass (2.85–2.60 Ga), strongly reworked during the Transamazonian orogeny (2.26–1.95 Ga). Geochemical and petrographic data together with combined zircon U–Pb and Lu–Hf (LA-ICP-MS) as well as whole-rock Sm–Nd (TIMS) dating, establish the chronology and petrogenesis of the granitoids and record the crustal growth and reworking at the transition between the Archean and Paleoproterozoic domains in the southeastern Guiana Shield. Two episodes, dated at ∼2.18–2.16 Ga and 2.14–2.13 Ga, respectively, include medium-to high-K calc-alkaline and metaluminous to peraluminous rocks of the Flexal and Papa-Vento intrusive suites, emplaced in a magmatic arc environment. A third episode, dated at ∼2.08 Ga, encompasses mostly peraluminous granites with a medium-to high-K calc-alkaline signature, of the syn-to late-collisional Vila Bom Jesus Suite. The zircon ƐHf (−3.5 to −4.3) and whole-rock ƐNd (−2.7 to −4.3) signatures with respective Hf-TDMC (2.9–3.1 Ga) and Nd-TDM (2.6–2.7 Ga) model ages indicate a mixture of Rhyacian juvenile material with a Mesoarchean crustal component for the magma sources of the Flexal and Papa-Vento intrusive suites. The geochemical characteristics, zircon ƐHf (−6.6 to −12.5) and whole rock ƐNd (−3.7 to −5.4) signatures, and Hf-TDMC (2.9–3.6 Ga) and Nd-TDM (2.7–2.9 Ga) model ages, together with the presence of Rhyacian (2.19 Ga) and Mesoarchean (2.82 Ga) inherited zircon crystals in the Vila Bom Jesus Suite, indicate dominant crustal reworking of Rhyacian magmatic arc rocks and Archean rocks from the adjacent Amapa Block during the arc-continent collision. The geochemical and isotopic signatures of the magmatic arc granitoids (Flexal and Papa-Vento intrusive suites) may be attributed to the incorporation in the juvenile magmatic sources of Archean continental sediments or hidden crustal fragments from the Amapa Block during the subduction processes. Geochemical affinities with continental magmatic arc and subchrondritic Hf–Nd isotopic signatures are consistent with a scenario of a long-lived Mesorhyacian (∼2.20–2.13 Ga), Cordilleran-type magmatic arc setting, which evolved to a collisional setting with the amalgamation of the Archean Amapa block and the Rhyacian Lourenco domain during the Neorhyacian (2.11–2.08 Ga).

中文翻译：

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圭亚那地盾东南部古元古代Lourenço域（巴西）的Rhyacian花岗岩的U-Pb年代学、Nd-Hf同位素和地球化学

摘要 巴西北部阿马帕州中东部地区古元古代 Lourenco 域的南段主要由 ​​Rhyacian 花岗岩-绿岩地体和一些太古代碎片组成。它位于与太古代阿马帕地块的过渡处，这是一个中-新太古代大陆陆块（2.85-2.60 Ga），在跨亚马逊造山运动（2.26-1.95 Ga）期间强烈改造。地球化学和岩石学数据，结合锆石 U-Pb 和 Lu-Hf (LA-ICP-MS) 以及全岩 Sm-Nd (TIMS) 测年，确定花岗岩的年代学和岩石成因，并记录地壳生长和在圭亚那地盾东南部太古代和古元古代域之间的过渡处进行改造。两集，日期分别为~2.18-2.16 Ga 和 2.14-2.13 Ga，包括位于岩浆弧环境中的 Flexal 和 Papa-Vento 侵入岩套的中至高 K 钙碱性和金属铝质至过铝质岩石。第三集日期为~2.08 Ga，主要包括具有中高K钙碱性特征的过铝花岗岩，即同步到晚期碰撞的Vila Bom Jesus Suite。分别具有 Hf-TDMC (2.9-3.1 Ga) 和 Nd-TDM (2.6-2.7 Ga) 模型年龄的锆石 ƐHf（-3.5 至 -4.3）和全岩 ƐNd（-2.7 至 -4.3）特征表明混合了Rhyacian 幼年物质，具有中太古代地壳成分，用于 Flexal 和 Papa-Vento 侵入岩套的岩浆来源。地球化学特征、锆石 ƐHf（-6.6 至 -12.5）和全岩 ƐNd（-3.7 至 -5.4）特征以及 Hf-TDMC（2.9-3.6 Ga）和 Nd-TDM（2.7-2.9 Ga）模型年龄一起随着 Rhyacian (2. 19 Ga) 和中太古代 (2.82 Ga) 在 Vila Bom Jesus Suite 中继承了锆石晶体，表明在弧-大陆碰撞期间，来自相邻 Amapa 地块的 Rhyacian 岩浆弧岩和太古代岩石的地壳改造占主导地位。岩浆弧花岗岩（Flexal 和Papa-Vento 侵入岩套）的地球化学和同位素特征可能归因于在俯冲过程中太古宙大陆沉积物或隐藏的地壳碎片的幼年岩浆源并入。与大陆岩浆弧和亚计时岩 Hf-Nd 同位素特征的地球化学亲和性与长寿中风纪 (~2.20-2.13 Ga)、科迪勒拉型岩浆弧环境的情景一致，