当前位置: X-MOL 学术J. South Am. Earth Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
U-PB LA-ICP-MS and geochemical data of the Alto Chapéu Pluton: Contributions on bimodal post-collisional magmatism in the Araçuaí belt (SE Brazil)
Journal of South American Earth Sciences ( IF 1.8 ) Pub Date : 2020-11-01 , DOI: 10.1016/j.jsames.2020.102724
Patrícia Anselmo Duffles Teixeira , Clarisse Monteiro Fernandes , Julio Cezar Mendes , Silvia Regina de Medeiros , Isabel Sant’Ana Rocha

Abstract Bimodal inversely zoned plutons were emplaced at the late stages in the Aracuai Belt, composing a tectonic corridor following the Atlantic coast of Brazil. This work presents original geochemical and geochronological data from the Alto Chapeu pluton, a post-collisional pluton that belongs to the G5 Supersuite of the Aracuai belt. It comprises inequigranular porphyritic granites and fine grained (monzo) diorites, showing transitional alkaline to calc-alkaline to subalkaline signature, wide silica range, metaluminious I-type character with low MgO, moderate to high alkali contents and enrichment in LREE. They are classified as monzodiorites, quartz syenites and granites. The monzodiorites and syenites present a discrete negative Eu anomaly, in contrast to the granites. In Harker diagrams, syenites plot between the granites and mozodiorites, defining a linear trend, suggesting chemical mixing between two contrasting magmas. A coherent trend in Harker diagrams with Santa Angelica samples, a neighboring pluton, suggests a cogenetic character between both bodies. U–Pb LA-ICP-MS zircon data yielded two concordia ages of 641 ± 5 Ma and 531 ± 4 Ma, both interpreted as magmatic crystallization. The first is related to inherited crystals from the host rock (Estrela orthogneiss), which is considered in the literature as correlated to the pre-collisional event, and the former is interpreted as crystallization age of the Alto Chapeu pluton, chronocorrelated with Aracuai belt post-collisional event.

中文翻译:

U-PB LA-ICP-MS 和 Alto Chapéu Pluton 的地球化学数据:对 Araçuaí 带(巴西东南部)双峰碰撞后岩浆作用的贡献

摘要 Aracuai 带晚期出现双峰反带岩体,构成了巴西大西洋沿岸的构造廊道。这项工作提供了来自 Alto Chapeu 岩体的原始地球化学和地质年代学数据,Alto Chapeu 岩体是属于 Aracuai 带 G5 Supersuite 的碰撞后岩体。它由不等粒状斑状花岗岩和细粒(monzo)闪长岩组成,显示过渡碱性到钙碱性到亚碱性的特征,二氧化硅范围宽,金属发光 I 型特征,低 MgO,中到高碱含量和轻稀土元素富集。它们被分类为二长闪长岩、石英正长岩和花岗岩。与花岗岩相反,二长闪长岩和正长岩呈现出离散的负 Eu 异常。在哈克图中,正长岩分布在花岗岩和莫佐闪长岩之间,定义线性趋势,表明两种对比岩浆之间的化学混合。哈克图中与圣当归样本(邻近的岩体)的一致趋势表明两个天体之间存在共同遗传特征。U-Pb LA-ICP-MS 锆石数据产生了两个 641 ± 5 Ma 和 531 ± 4 Ma 的协和年龄,均被解释为岩浆结晶。第一个与来自母岩(Estrela orthogneiss)的继承晶体有关,在文献中被认为与碰撞前事件相关,前者被解释为 Alto Chapeu 岩体的结晶年龄,与 Aracuai 带柱的年代相关- 碰撞事件。表明两个身体之间存在共同遗传特征。U-Pb LA-ICP-MS 锆石数据产生了两个 641 ± 5 Ma 和 531 ± 4 Ma 的协和年龄,均被解释为岩浆结晶。第一个与来自母岩(Estrela orthogneiss)的继承晶体有关,在文献中被认为与碰撞前事件相关,前者被解释为 Alto Chapeu 岩体的结晶年龄,与 Aracuai 带柱的年代相关- 碰撞事件。表明两个身体之间存在共同遗传特征。U-Pb LA-ICP-MS 锆石数据产生了两个 641 ± 5 Ma 和 531 ± 4 Ma 的协和年龄,均被解释为岩浆结晶。第一个与来自母岩(Estrela orthogneiss)的继承晶体有关,在文献中被认为与碰撞前事件相关,前者被解释为 Alto Chapeu 岩体的结晶年龄,与 Aracuai 带柱的年代相关- 碰撞事件。
更新日期:2020-11-01
down
wechat
bug