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U-Pb provenance fingerprints of metavolcanic-sedimentary successions of the Mineiro belt: Proxies for the continuity of plate tectonics through the Paleoproterozoic
Geoscience Frontiers ( IF 8.9 ) Pub Date : 2021-08-26 , DOI: 10.1016/j.gsf.2021.101293
W. Teixeira 1 , C.A. Ávila 2 , I.A. Dussin 3 , E. Bongiolo 4
Affiliation  

We document new U-Pb detrital zircon LA-MC-ICP-MS data for seven metavolcanic-sedimentary successions and metasedimentary sequences and reassess additional dates of five siliciclastic samples toward their tectonic significance in the context of the Mineiro belt, Southern São Francisco Craton. This belt represents a crustal segment of the 2.47–2.00 Ga Minas Orogen, classically known by its Siderian and Rhyacian juvenile rocks with important implications in the Earth's geodynamics. The new and compiled detrital provenance constraints unravel the long-lived magmatic and sedimentary history of the studied basins, lasting ca. 230–220 Myr. The maximum depositional dates around 2.1 Ga reflect the renewed sediment budget with the subsequent metamorphic episode ca. 2.0 Ga. Most of the unmixed relative probability diagrams are consistent with sourcing from the Siderian and Rhyacian arcs of the Mineiro belt, determining a detrital provenance change in time and space for the precursor basins. Alternative potential sources could be the youngest rocks of the Mantiqueira and Juiz de Fora terranes that constitute the other segments of the Minas Orogen, given the age match. The overall detrital fingerprints determine the study basins resumed mainly in Rhyacian fore-arc and/or back-arc settings, i.e., akin to a subduction-related system that evolved to a collisional (foreland) environment. Few samples show fingerprints of primary extensional settings, determined by major Archean detrital populations sourced from areas outside the Mineiro belt beside the Paleoproterozoic detritus. The working model considers the collage between the Mineiro belt and the ancient foreland around 2.10 Ga and eventual interaction with other crustal segments of the Minas Orogen, generating the ca. 2.0 Ga metamorphism over the metasedimentary samples. The more complete isotopic repository in detrital and igneous zircon grains for the studied supracrustal successions and the associated rocks allows new insights into the Rhyacian-Orosirian dynamics of the Minas orogeny. In a broader perspective, the juvenile nature of the Mineiro belt reinforces the paradigm of uninterrupted continental growth during the Paleoproterozoic Earth.



中文翻译:

Mineiro 带变质火山-沉积序列的 U-Pb 来源指纹:通过古元古代板块构造连续性的代表

我们记录了七个变质火山沉积序列和变沉积序列的新 U-Pb 碎屑锆石 LA-MC-ICP-MS 数据,并重新评估了五个硅质碎屑样品的其他日期,以了解它们在南圣弗朗西斯科克拉通 Mineiro 带背景下的构造意义。该带代表 2.47-2.00 Ga 米纳斯造山带的地壳部分,经典上以其对地球地球动力学具有重要意义的 Siderian 和 Rhyacian 幼岩而闻名。新的和编纂的碎屑物源限制揭示了研究盆地的长期岩浆和沉积历史,持续时间约为 230–220 密尔 大约 2.1 Ga 的最大沉积日期反映了更新的沉积物预算以及随后的变质事件约。2.0 加仑。大多数未混合的相对概率图与来自 Mineiro 带的 Siderian 和 Rhyacian 弧的来源一致,确定了前体盆地在时间和空间上的碎屑来源变化。考虑到年龄匹配,替代的潜在来源可能是构成米纳斯造山带其他部分的 Mantiqueira 和 Juiz de Fora 地体中最年轻的岩石。总体碎屑指纹确定主要在 Rhyacian 前弧和/或后弧环境中恢复的研究盆地,即类似于演化为碰撞(前陆)环境的俯冲相关系统。很少有样本显示原始伸展环境的指纹,这是由来自古元古代碎屑旁边的米内罗带以外地区的主要太古代碎屑种群确定的。工作模型考虑了米内罗带和大约 2.10 Ga 的古代前陆之间的拼贴以及与米纳斯造山带其他地壳部分的最终相互作用,产生了大约 变沉积样品上的 2.0 Ga 变质作用。用于研究的地壳层序和相关岩石的碎屑和火成岩锆石颗粒中更完整的同位素库允许对米纳斯造山运动的 Rhyacian-Orosirian 动力学有新的见解。从更广泛的角度来看,米内罗带的幼年性质加强了古元古代地球大陆不间断生长的范式。用于研究的地壳层序和相关岩石的碎屑和火成岩锆石颗粒中更完整的同位素库允许对米纳斯造山运动的 Rhyacian-Orosirian 动力学有新的见解。从更广泛的角度来看,米内罗带的幼年性质加强了古元古代地球大陆不间断生长的范式。用于研究的地壳层序和相关岩石的碎屑和火成岩锆石颗粒中更完整的同位素库允许对米纳斯造山运动的 Rhyacian-Orosirian 动力学有新的见解。从更广泛的角度来看,米内罗带的幼年性质加强了古元古代地球大陆不间断生长的范式。

更新日期:2021-08-26
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