The eastern portion of the Dom Feliciano Belt in southernmost Brazil, known as Pelotas Terrane, is composed of Neoproterozoic rocks presenting metamorphic xenoliths in granitoid rocks, described and interpreted as “basement inliers”. Based on novel petrographic, mineral/whole rock/Sr–Nd geochemistry and U–Pb geochronological data, this paper presents the first record of a Paleoproterozoic metagabbro xenolith in the Pelotas Terrane. The studied xenolith exhibits a sharp and angular contact with the host rock and a predominant granoblastic texture, with sub-vertical mm-to cm-thick metamorphic banding, marked by the felsic and mafic bands, composed respectively of bytownite (An₈₅) ± quartz, and diopside ± tremolite ± epidote. Zircon, apatite, and iron/titanium oxides occur as accessory minerals. The peak metamorphism for this rock is estimated at amphibolite facies conditions. The whole-rock chemistry of the metagabbro suggests a basic derivation (e.g., SiO₂ 52 wt%; Al₂O₃ 12 wt%; Ni 33 ppm). The spidergrams demonstrate high LILE and HFSE concentrations. Chondrite-normalized REE patterns show enrichment in LREE. The Sr–Nd isotopic data show ⁸⁷Sr/⁸⁶Sr_(i) = 0.701024, εNd_(i) = 5.44, and Nd-T_DM = 2.1 Ga. The metagabbro yielded a U–Pb Concordia age with analytical points arranged in a Discordia line. The upper intercept was interpreted as a magmatic crystallization age of 2.1 Ga (zircon cores), and the lower intercept indicated a resetting age of 616 Ma (zircon rims). The obtained Archean age (2.8 Ga) is interpreted as inherited. Gabbro's metamorphism likely reached the amphibolite facies, elemental and isotopic geochemistry. The remote zircon inheritance of xenoliths that have had polycyclic survival is used to link the occurrence of a gabbro xenolith, in the Pelotas Terrane (Dom Feliciano Belt; Southern Brazil), whose magmatic crystallization age is Paleoproterozoic, with the basement terranes before the Namaquan orogeny, in the Rehoboth region (Gariep Belt and Bushmanland/Namaqualand; Namibia). These units could be related to the evolution of an ancient Paleoproterozoic magmatic arc formed by the convergence of two Archean continents during the evolution of the Atlantica Supercontinent.

巴西最南端的 Dom Feliciano 带的东部被称为 Pelotas Terrane，由新元古代岩石组成，在花岗质岩石中呈现变质捕虏体，被描述和解释为“基底内层”。基于新的岩相学、矿物/全岩/Sr-Nd地球化学和U-Pb年代学数据，本文首次提出了Pelotas地体中古元古代超辉长岩捕虏体的记录。所研究的捕虏体与主岩呈尖锐的角接触，并具有主要的花岗碎屑结构，具有亚垂直毫米至厘米厚的变质带，以长英质和镁铁质带为标志，分别由bytownite（An ₈₅）±石英组成, 透辉石 ± 透闪石 ± 绿帘. 锆石、磷灰石和铁/钛氧化物作为辅助矿物出现。在角闪岩相条件下估计该岩石的峰值变质作用超长岩的全岩化学表明有一个基本的衍生物（例如，SiO ₂52 wt%；Al₂O₃12 wt%；Ni 33 ppm）。蜘蛛图显示出高浓度的 LILE 和 HFSE。球粒陨石标准化 REE 模式显示 LREE 富集。Sr–Nd 同位素数据显示⁸⁷Sr/⁸⁶Sr_(i) = 0.701024，εNd_(i) = 5.44，Nd-T_DM = 2.1 Ga。metagabbro 产生了 U-Pb Concordia 年龄，分析点排列在 Discordia 线上。上截距被解释为 2.1 Ga（锆石核）的岩浆结晶年龄，下截距表明重置年龄为 616 Ma（锆石边缘）。获得的太古代（2.8 Ga）被解释为遗传。辉长岩的变质作用可能达到了角闪岩相、元素和同位素地球化学。具有多循环生存的捕虏体的远程锆石遗传被用来将辉长岩捕虏体的出现与岩浆结晶年龄为古元古代的 Pelotas 地体（Dom Feliciano 带；巴西南部）与纳马泉之前的基底地体联系起来造山运动，在里霍博斯地区（加里普带和布什曼兰/纳马夸兰；纳米比亚）。这些单位可能与大西洋超大陆演化过程中两个太古代大陆会聚形成的古古元古代岩浆弧的演化有关。