Abstract Deformed alkaline rocks and carbonatites (DARCs) can be important tectonic indicators of regions that have experienced two separate events of rifting and collision, but can also represent alkaline magmas that were synkinematically emplaced along major structures and were therefore generated and deformed in the same geologic event. The Monte Santo Suite consists of two foliated and variably deformed massifs (Estrela and Monte Santo) that crop out in the Araguaia Belt and are characterized by igneous and subsolidus microstructures. In this study, we use the chemistry, mineralogy and age of the Monte Santo Suite to understand its genesis and the relations between its emplacement, the Brasiliano-Pan-African orogeny and the final evolution of Western Gondwana. The intrusions are predominantly nepheline syenite and alkali feldspar syenite. Pyroxene varies in composition from omphacite to aegirine-augite to aegirine and has mixed igneous and metamorphic characteristics. Biotite varies from phlogopite to siderophyllite to annite and presents primary, reequilibrated and neoformed trends. Amphibole varies from hastingsite to taramite. Nepheline occurs as both high-temperature and low-temperature varieties. The REE and trace element patterns display parallel trends with significant bulk content variations, positive anomalies for Nb, Ta, Zr and Hf, and negative anomalies for Ba, Sr, P and Ti in multielement diagrams, The Zr/Hf ratios for all the rocks of the massifs are similar and whole-rock eNd values range from −10.1 to −3.0. Trace element and isotopic data suggest that these magmas experienced extensive fractional crystallization, crustal contamination, and evolved from the same source, probably an enriched mantle. The Monte Santo Suite crystallization age is dated to 545 Ma, when these magmas were generated and deformed synkinematically with shearing along major regional faults related to the Transbrasiliano Lineament. Thus, this suite is an example of alkaline rocks generated and deformed in the same geological event throughout Western Gondwana.

中文翻译：

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Monte Santo 套房，巴西中部阿拉瓜亚带埃迪卡拉纪-寒武纪变形碱性岩的一个例子。对西冈瓦纳演化的影响

摘要 变形碱性岩和碳酸岩 (DARCs) 可以是经历过两次独立的裂谷和碰撞事件的地区的重要构造指标，但也可以代表沿主要构造同运动侵位并因此在同一地质条件下生成和变形的碱性岩浆。事件。Monte Santo Suite 由两个叶状且变形可变的地块（Estrela 和 Monte Santo）组成，它们出现在 Araguaia 带中，以火成岩和亚固相微结构为特征。在这项研究中，我们利用 Monte Santo Suite 的化学、矿物学和年龄来了解它的成因以及它的就位、巴西-泛非造山运动与西冈瓦纳大陆的最终演化之间的关系。侵入体主要是霞石正长岩和碱性长石正长岩。辉石的成分从绿辉石到绿辉石-辉石再到绿辉石，具有混合的火成岩和变质特征。黑云母从金云母到铁蜡石再到安妮石，呈现出原始、再平衡和新形成的趋势。角闪石从黑斯廷石到塔拉米石不等。霞石作为高温和低温品种出现。REE 和微量元素模式显示出平行趋势，体积含量变化显着，多元素图中 Nb、Ta、Zr 和 Hf 为正异常，Ba、Sr、P 和 Ti 为负异常，所有岩石的 Zr/Hf 比率的地块相似，全岩 eNd 值范围从 -10.1 到 -3.0。微量元素和同位素数据表明，这些岩浆经历了广泛的分步结晶、地壳污染、并且从同一个来源进化而来，可能是一个丰富的地幔。Monte Santo Suite 的结晶年龄可追溯到 545 Ma，当时这些岩浆是沿着与 Transbrasiliano Lineament 相关的主要区域断层的剪切而产生和同运动变形的。因此，该组是在整个西冈瓦纳大陆的同一地质事件中生成和变形的碱性岩石的一个例子。