Eoarchean to Neoproterozoic crustal evolution of the Mantiqueira and the Juiz de Fora Complexes, SE Brazil: Petrology, geochemistry, zircon U-Pb geochronology and Lu-Hf isotopes
Eoarchean to Neoproterozoic crustal evolution of the Mantiqueira and the Juiz de Fora Complexes, SE Brazil: Petrology, geochemistry, zircon U-Pb geochronology and Lu-Hf isotopes
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DOI：
10.1016/j.precamres.2019.01.008
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发表时间：
2019-04
影响因子：
3.8
通讯作者：
Y. Kuribara;T. Tsunogae;M. Santosh;Yusuke Takamura;A. Costa;C. Rosière
中科院分区：
文献类型：
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作者：
Y. Kuribara;T. Tsunogae;M. Santosh;Yusuke Takamura;A. Costa;C. Rosière
巴西东南部Araçuaí-Ribeira造山系中的Mantiqueira和Juiz de Fora杂岩（MQC和JFC）被认为是新元古代至寒武纪巴西造山运动的一部分，由弗朗西斯科和刚果的一系列碰撞形成。在这里，我们报告新的岩石学，地球化学和锆石U-Pb和Lu-Hf同位素数据的长英质镁铁质正片麻岩的复杂，以期评估的时间和P-T条件的碰撞事件以及原岩的形成。正片麻岩的变质P-T估计表明，MQC的角闪岩相条件为650-730 °C和5.8-9.1 kbar，而JFC的条件略高（上部角闪岩相至下部麻粒岩相），为680-770 °C和6.0-7.7 kbar。长英质正片麻岩的地球化学、锆石U-Pb年代学和Lu-Hf同位素资料表明，MQC是由一系列新太古代（约1000年）的岩浆活动形成的。2.67和2.61 Ga）火山弧岩浆作用，岩浆来源于始新世至古太古代（约. 3.82-3.42 Ga）地壳成分。与此相反，略年轻的U-Pb年龄约。2380年，马。2050-1960 Ma，标志着火山弧岩浆活动的时代为早-中古元古代，岩浆来源于古太古代（103.45 Ga）地壳，并含有新生地壳成分。再生的古地壳成分也提供了晚新元古代（约。600 Ma）的JFC大陆弧岩浆活动。高级变质作用可能与刚果和弗朗西斯科造山带在590-560 Ma的最后碰撞有关，这与Kuunga造山带的形成大致相当。
The Mantiqueira and the Juiz de Fora Complexes (MQC and JFC) in the Araçuaí-Ribeira orogenic system, southeastern Brazil, have been regarded as parts of the Neoproterozoic to Cambrian Brasiliano Orogeny formed by a series of collisions of the São Francisco and the Congo Cratons. Here we report new petrological, geochemical, and zircon U-Pb and Lu-Hf isotopic data on felsic to mafic orthogneisses from the complexes with a view to evaluate the timing andP-Tconditions of the collisional event as well as protolith formation. MetamorphicP-Testimates for orthogneisses indicate amphibolite-facies conditions of 650–730 °C and 5.8–9.1 kbar from the MQC, whereas slightly higher (upper amphibolite- to lower granulite-facies) conditions of 680–770 °C and 6.0–7.7 kbar were obtained from the JFC. Geochemical, zircon U-Pb geochronological, and Lu-Hf isotopic data of felsic orthogneisses indicate that the MQC was formed by a series of Neoarchean (ca. 2.67 and 2.61 Ga) volcanic arc magmatisms with magma sourced from Eoarchean to Paleoarchean (ca. 3.82–3.42 Ga) crustal components. In contrast, slightly younger U-Pb ages of ca. 2380 Ma and ca. 2050–1960 Ma were obtained from the JFC marking the timing of volcanic arc magmatism as Early to Middle Paleoproterozoic, with magma sourced from Paleoarchean (∼3.45 Ga) crust with addition of juvenile crustal components. The recycled ancient crustal components were also supplied for late Neoproterozoic (ca. 600 Ma) continental arc magmatism of the JFC. The high-grade metamorphism is possibly related to the final collision of the Congo and São Francisco Cratons at 590–560 Ma, which broadly compares with the formation of the Kuunga Orogen.