Ediacaran to Cambrian tectonomagmatic events in the Southern Dom Feliciano Belt, Uruguay: from a plate margin to an intraplate setting and the assembly of SW Gondwana
Ediacaran to Cambrian tectonomagmatic events in the Southern Dom Feliciano Belt, Uruguay: from a plate margin to an intraplate setting and the assembly of SW Gondwana
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DOI：
10.1016/j.gr.2022.12.004
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发表时间：
2022-12
影响因子：
6.1
通讯作者：
T. Will;C. Gaucher;H. Frimmel;Xiaoxiao Ling;W. Shi;X.‐H. Li;Q.L. Li
中科院分区：
文献类型：
--
作者：
T. Will;C. Gaucher;H. Frimmel;Xiaoxiao Ling;W. Shi;X.‐H. Li;Q.L. Li
本文介绍了乌拉圭Cuchilla Dionisio（CDT）、Nico Pérez（NPT）和Tandilia（TT）火山岩埃迪卡拉纪岩浆岩的锆石U-Pb年代学和Hf-O同位素数据以及全岩地球化学和Sr-Nd-Pb同位素地球化学数据。三种不同的岩石套件在NPT中得到认可。第1组岩石为高Ba-Sr花岗闪长岩、二长岩和正长岩，形成于610 ± 3 ~ 593 ± 5 Ma之间的俯冲基性岩源，可能形成于伸展环境。第2组岩体（正长岩）形成于573 ± 8 ~ 563 ± 7 Ma之间的镁铁质源区，侵位于拉普拉塔东延板块边缘的板内环境。第3组岩石和TT中的拉巴斯花岗岩都是板内花岗岩，它们是由地壳熔融和/或在c. 557 ± 4Ma。早埃迪卡拉世瓦尔迪维亚岩体是一个俯冲相关的花岗岩，形成于活动大陆边缘的镁铁质熔体。571 ± 3 Ma和566 ± 6 Ma与俯冲有关的CDT José伊格纳西奥和弗洛伦西亚花岗岩侵位在活动边缘或附近。它们和瓦尔迪维亚花岗岩一样，只提供了很少的证据，证明它们含有地壳岩石和/或熔体。CDT中的同时代马尔多纳多和罗查花岗岩与俯冲有关，但位于弧的远端。早寒武世Santa Teresa花岗岩是一个碰撞相关的岩体，形成于532 ± 6 Ma的冈瓦纳西南部最后组装过程中。很明显，在乌拉圭南部的Dom Feliciano带Ediacaran早寒武世火成岩起源于不同的源区，并在不同的时间在不同的构造环境中侵位。这些数据表明，从早期埃迪卡拉俯冲有关，弧型岩浆作用板内，最后到晚埃迪卡拉/早寒武世碰撞有关的火成岩活动在乌拉圭部门的南部多姆费利西亚诺带的过渡。
We present new zircon U-Pb geochronological and Hf-O isotope data as well as whole rock geochemical and Sr-Nd-Pb isotope geochemical data of Ediacaran magmatic rocks from the Cuchilla Dionisio (CDT), Nico Pérez (NPT) and Tandilia (TT) terranes in Uruguay. Three different rock suites are recognized in the NPT. The Group 1 rocks are high Ba-Sr granodiorite, monzonite and syenite that formed from a subduction-related mafic source between 610 ± 3 and 593 ± 5 Ma, most likely in an extensional setting. The Group 2 plutons, syenite, formed from a mafic source between 573 ± 8 and 563 ± 7 Ma and were emplaced in an intraplate setting at the extended eastern Rio de la Plata cratonic margin. The Group 3 rocks as well as the La Paz Granite in the TT are intraplate granites that formed by crustal melting and/or by the incorporation of crustal melts at c. 557 ± 4 Ma. The Early Ediacaran Valdivia Pluton in the CDT is a subduction-related granite that formed from a mafic melt at an active continental margin. The 571 ± 3 and 566 ± 6 Ma subduction-related CDT José Ignacio and Florencia granites were emplaced at or close to an active margin. They, like the Valdivia Granite provide only little evidence of incorporating crustal rocks and/or melts. The coeval Maldonado and Rocha granites in the CDT are subduction-related but were emplaced in a distal position to the arc. The Early Cambrian Santa Teresa Granite is a collision-related pluton that formed during the final assembly of SW Gondwana at 532 ± 6 Ma. It is evident that the Ediacaran to Early Cambrian igneous rocks in the southern Dom Feliciano Belt in Uruguay originated from dissimilar source regions and were emplaced in different tectonic settings at different times. The data indicate a transition from Early Ediacaran subduction-related, arc-type magmatism to intraplate and, finally to Late Ediacaran/Early Cambrian collision-related igneous activity in the Uruguayan sector of the southern Dom Feliciano Belt.