The southern Brasília belt (SBB) evolved during the Neoproterozoic amalgamation of Western Gondwana. The Andrelândia nappe system (ANS) is part of the SBB and a key area to understand the tectono-metamorphic evolution of the SBB due to the ongoing controversy concerning whether peak metamorphism occurred at >650 Ma, >618 Ma or 605 Ma in the upper nappe of the ANS. A kyanite-garnet-bearing felsic granulite from the Três Pontas-Varginha nappe (TPVN) in the ANS was investigated to constrain the pressure-temperature (P-T)-time evolution. For this purpose, we applied thermodynamic modelling with P-T pseudosections contoured by garnet compositional isopleths and monazite in-situ dating by LA-ICP-MS. Early garnet (Gt I) formed in the P-T range of 11-20 kbar and 495-595 °C based on the garnet core composition. This growth was followed by resorption at retrograde conditions. Mineralogical changes during a second metamorphic cycle are discernible by new growth of garnet (Gt II) with a significantly different composition compared to Gt I. The P-T climax reached 13 ± 1.5 kbar and 800 ± 50 °C, accompanied by partial melting. The two metamorphic cycles are assigned to two successive burial-exhumation events that ended with nappe stacking and formation of the TPVN. Monazite occurring in garnet (Gt II) and in the matrix contains Y concentrations of 0.1-3.5 wt.% independent of the textural position, but positively correlated with HREE contents, supporting the formation of all monazite during corrosion of Gt I and early growth of Gt II. Dating of monazite yielded a concordia age of 617.1 ± 3.8 (2σ) Ma. We assign this age to the end of the first P-T loop and beginning of the second loop. Literature data suggest two ages, close to 650 Ma and 605 Ma, for the P-T climax in the TPVN. The age difference of ca. 45 Ma fits a multiple metamorphic evolution similar to Phanerozoic orogens, characterized by a difference in time between two metamorphic peaks in the range of tens of million years (15-60 Ma) within a single orogenic cycle. This points to an orogenic evolution in the late Neoproterozoic (Brasiliano/Pan-African orogenesis) that had the character of modern mountain-building processes.

巴西利亚南部带（SBB）在冈瓦纳西部的新元古代合并过程中演化而成。Andrelândia推覆系统（ANS）是SBB的组成部分，也是了解SBB构造变质演化的关键领域，这是由于有关上部上端变质发生在> 650 Ma，> 618 Ma还是605 Ma的争论不断ANS的尿布。研究了来自ANS中TrêsPontas-Varginha nappe（TPVN）的含蓝宝石-石榴石的长英质粒状花岗岩，以限制压力-温度（PT）-时间演化。为此，我们应用了热力学模型，并通过LA-ICP-MS用石榴石成分等值线和独居石定年法绘制了PT假剖面轮廓。PT中形成了早期石榴石（Gt I）根据石榴石芯成分，温度范围为11-20 kbar和495-595°C。生长之后，在逆行条件下吸收。相比亿吨一，第二变质循环期间矿物学变化是由（GT II）的石榴石新的增长与显著不同组合物可辨别PT高潮达到13±1.5 kbar和800±50°C，并伴有部分融化。将两个变质周期分配给两个连续的埋葬-掘尸事件，这些事件以推覆堆积和TPVN的形成结束。石榴石（Gt II）和基质中存在的独居石的Y浓度为0.1-3.5 wt。％，与织构位置无关，但与HREE含量呈正相关，支持在Gt I腐蚀和Gt早期生长期间所有独居石的形成。 Gt II。独居石约会产生的共生年龄为617.1±3.8（2σ）Ma。我们将此年龄分配给第一个PT循环的结尾和第二个循环的起点。文献数据表明，PT有两个年龄，分别接近650 Ma和605 Ma。TPVN中的高潮。年龄约。45 Ma适合于类似于变生代造山带的多种变质演化，其特征是在单个造山周期内，两个变质峰之间的时间差在几千万年（15-60 Ma）范围内。这表明新元古代晚期（巴西利亚/泛非造山运动）的造山运动具有现代山区建造过程的特征。