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首页> 外文期刊>Brazilian Journal of Geology >Tectonic evolution of the Dom Feliciano Belt in Southern Brazil: Geological relationships and U-Pb geochronology
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Tectonic evolution of the Dom Feliciano Belt in Southern Brazil: Geological relationships and U-Pb geochronology

机译：巴西南部Dom Feliciano带的构造演化：地质关系和U-Pb年代学

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The Dom Feliciano Belt is an important Neoproterozoic to Cambrian orogenic complex, extending from eastern Uruguay to southern Brazil. It comprises a collage of oceanic domains and continental fragments developed between 900 and 540 Ma between the Rio de La Plata, Congo and Kalahari cratons. The integration of field and structural data with recent isotopic results has introduced new insights on the sources of the magmatism and sedimentary processes. This paper presents a review of the geochronological results combined with stratigraphic, structural and geochemical data. The evolution of the Dom Feliciano Belt involved three orogenic events known as the Passinho (0.89 - 0.86 Ga), S?￡o Gabriel (0.77 - 0.68 Ga) and Dom Feliciano (0.65 - 0.54 Ga). The first two events involved the closure of the Charrua Ocean generating an intra-oceanic arc (Passinho) and, subsequently, an active continental margin arc (S?￡o Gabriel). This ocean separated the continental areas represented by the Rio de la Plata Craton and the Nico Perez continental microplate. Closure of the Adamastor ocean resulted in an important collisional event between the Nico Perez Microplate/Rio de La Plata Craton and Kalahari and Congo cratons between 650 and 620 Ma, involving high T/intermediate P metamorphism. At this time of crustal thickening, the partition of the deformation controled the final evolution of the belt with important escape tectonics, responsible for nucleating crustal-scale transcurrent shear zones. These structures were deep and promoted the rise of mafic magmas, which, associated with high regional thermal gradient, lead to an important event of crustal reworking, responsible for the formation of the Pelotas Batholith. The orogenic collapse is represented by late magmatism of Pelotas Batholith and deposition of upper section of the Camaqu?￡ Basin.
机译：Dom Feliciano带是寒武纪造山带的重要新元古代，从乌拉圭东部延伸到巴西南部。它由拉普拉塔河，刚果河和卡拉哈里克拉通之间900至540 Ma之间的海洋区域和大陆碎片组成的拼贴画。现场和结构数据与最新同位素结果的结合，为岩浆作用和沉积过程的来源提供了新见解。本文介绍了结合地层，结构和地球化学数据的地质年代结果。 Dom Feliciano带的演化涉及三个造山事件，分别称为Passinho（0.89-0.86 Ga），S？o Gabriel（0.77-0.68 Ga）和Dom Feliciano（0.65- 0.54 Ga）。前两个事件涉及查鲁亚海洋的关闭，产生了洋内弧（Passinho），随后又产生了活跃的大陆边缘弧（S ￡ o Gabriel）。这片海洋将里约热内卢克拉通和尼科·佩雷斯大陆微板块所代表的大陆区分开。 Adamastor海洋的封闭导致Nico Perez Microplate / Rio de La Plata Craton与Kalahari和刚果克拉通之间的重要碰撞事件发生在650至620 Ma之间，涉及高T /中P变质作用。在地壳增厚时，变形的分区控制了带的重要逃逸构造带的最终演化，从而使地壳尺度的横流剪切带成核。这些结构很深，并促进了镁铁质岩浆的上升，这与高区域热梯度相关，导致了地壳再造的重要事件，造成了Pelotas岩床的形成。造山塌陷的特征是Pelotas岩床的晚期岩浆作用和Camaqu ￡盆地上部的沉积。

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