In this contribution we present new insights on the evolution of the Dom Feliciano Belt, southernmost Mantiqueira Province, integrating new whole-rock Sm–Nd isotopic data for the Arroio Grande Ophiolite (Punta del Este Terrane, Brazil/Uruguay border) with previously published bulk-rock and isotope geochemistry of the South Adamastor paleo-ocean metamafic rocks located in Uruguay (Paso del Dragón Complex, Punta del Este Terrane) and Namibia (Chameis Subterrane, Marmora Terrane, Gariep Belt). For the regional geology, the new data corroborate previous hypothesis and demonstrate the depleted mantle features of the amphibolites and metagabbros of the studied ophiolite. The Arroio Grande Ophiolite rocks are compared with its Uruguayan and Namibian counterparts, demonstrating their isotopic and geochemical similarities and differences, and the back-arc affinity of the South Adamastor paleo-ocean. The MORB-affinity amphibolites from the Arroio Grande Ophiolite-Paso del Dragón Complex are, so far, the most juvenile rocks in the eastern sector of the Dom Feliciano Belt, yielding ε_{Nd(640 ​Ma)} between +7.3 and ​+ ​9, and high ¹⁴⁷Sm/¹⁴⁴Nd (>0.169) and ¹⁴³Nd/¹⁴⁴Nd_(640 ​Ma) ratios (0.51219–0.51229). The South Adamastor is interpreted in this paper as an internal back-arc ocean, with limited lateral extension, opened at around 750–650 ​Ma as the result of the closure of the older Charrua-Goianide paleo-ocean during the Brasiliano/Pan-African orogenic cycle and final configuration of the West Gondwana paleocontinent.

在此贡献中，我们提供了有关Mantiqueira省最南端的Dom Feliciano带演化的新见解，并结合了Arroio Grande Ophiolite（巴西埃拉蓬塔拉边界/乌拉圭边界）的全新全岩Sm-Nd同位素数据，以及先前发表的大量文献位于乌拉圭（Paso delDragónComplex，Punta del Este Terrane）和纳米比亚（Chameis Subterrane，Marmora Terrane和Gariep Belt）的南Adamastor古海洋变质岩的岩石和同位素地球化学。对于区域地质，新数据证实了先前的假设，并证明了所研究蛇绿岩的闪石和变辉岩的地幔特征枯竭。将Arroio Grande Ophiolite岩石与乌拉圭和纳米比亚的岩石进行了比较，证明了它们在同位素和地球化学方面的异同，以及南阿达马斯托尔古海洋的弧后亲和力。到目前为止，来自Arroio Grande Ophiolite-Paso delDragón复合体的MORB亲和性闪石是Dom Feliciano Belt东区最幼稚的岩石，ε_{的Nd （640 Ma）的}7.3和+ 9，和高之间¹⁴⁷ SM / ¹⁴⁴钕（> 0.169）和¹⁴³的Nd / ¹⁴⁴的Nd _{（640 Ma）的}比（0.51219-0.51229）。在本文中，南Adamastor被解释为内部弧后海洋，横向扩展有限，由于巴西利亚（Brasiliano / Pan-Pan）时期较早的Charrua-Goianide古海洋关闭而在大约750-650 Ma开放非洲造山周期和西冈瓦纳古大陆的最终构造。