Large amounts of high BaSr magmatism can be produced as the result of late accretion or decompression in the final stages of continental arc evolution in orogenic systems and leads to continental crustal growth. This type of magmatism often occurs associated with mega-shear zones and displays geochemical signatures that indicate magmas deriving from the melting of enriched lithospheric mantle. Such enrichment may be an indication of slab-derived fluid and/or melt interaction, released from subducted material. The high BaSr granitoids of the Brasiliano Paraguay Belt, Tocantins Province, central Brazil, comprise two suites that crystallized approximately 40 My apart from each other. Both suites are composed of metaluminous to slightly peraluminous rocks (ASI = 0.64–1.09) with magnesian character, and present high Ba (~1430 ppm), Sr (~800 ppm), K₂O (~4 wt%), LREE and LILE contents. The negative ε_Nd(T) values (−6.32 and − 6.65) associated with high contents of incompatible elements indicate an evolution from partial melting of mantle-derived magma previously metasomatized by subducted slab fluids. Crystallization ages of 557 ± 5.7 Ma and 554 ± 2.9 Ma have been obtained for the older, high MgK calc-alkaline suite. It evolved from high Cr and Ni mantle-derived appinitic magma to coeval granodiorites by crystal fractionation accompanied by minor crustal contamination. The younger, 515 ± 3.6 Ma-old suite displays an elevated concentration in some HFSEs, show alkali-calcic affinity and is represented by high-K monzogranites. A model proposed for the two hybrid suites is based on a slab break-off and a subsequent lithospheric delamination after 40 My, where the heat flux generated by mantle upwelling led to a partial melting of the enriched subcontinental lithospheric mantle beneath the continental crust. The older calc-alkaline suite represents the end process of magmatic arc accretion in the central Tocantins Province. The younger one is compatible with a transitional shoshonitic to A-type affinity, associated to post-collisional collapse stage of the orogen at Cambrian times. The petrogenesis of the investigated rocks requires an ocean closure phase at ca. 590 Ma, which could be linked to the consumption of the Clymene Ocean toward Amazonian Craton, recording a new collisional event in the central West Gondwana.

造山系统大陆弧演化末期后期增生或减压可产生大量高Ba Sr岩浆活动，导致大陆地壳生长。这种类型的岩浆活动通常与巨型剪切带相关联，并显示出地球化学特征，表明岩浆来自富集岩石圈地幔的熔化。这种富集可能是从俯冲物质释放的板坯衍生流体和/或熔体相互作用的指示。高巴巴西中部托坎廷斯省 Brasiliano Paraguay Belt 的 Sr 花岗岩包括两套结晶，彼此相距约 40 My。两组均由具有镁质特征的金属铝质至微铝质岩石 (ASI = 0.64–1.09) 组成，并存在高 Ba (~1430 ppm)、Sr (~800 ppm)、K ₂ O (~4 wt%)、LREE 和LILE 内容。与高含量不相容元素相关的负 ε _Nd (T) 值（-6.32 和 - 6.65）表明先前被俯冲板片流体交代的地幔源岩浆的部分熔融演化。已获得 557 ± 5.7 Ma 和 554 ± 2.9 Ma 的较老、高镁的结晶年龄K钙碱性套件。它从高铬和镍地幔来源的appinitic岩浆通过晶体分馏伴随着轻微的地壳污染演化为同时代的花岗闪长岩。较年轻的 515 ± 3.6 Ma 旧套件在某些 HFSE 中显示出升高的浓度，显示出碱-钙亲和力，并以高 K 二长花岗岩为代表。为这两个混合套件提出的模型基于 40 My 之后的板片断裂和随后的岩石圈分层，其中地幔上涌产生的热通量导致大陆地壳下方富集的次大陆岩石圈地幔部分熔化。较旧的钙碱性套件代表了托坎廷斯省中部岩浆弧增生的结束过程。年轻的与过渡性的 shoshonitic 到 A 型亲和力相容，与寒武纪造山带碰撞后塌陷阶段有关。所研究岩石的岩石成因需要在大约 10 小时的海洋闭合阶段。590 Ma，这可能与克莱门洋对亚马逊克拉通的消耗有关，记录了冈瓦纳西部中部的新碰撞事件。