Neoproterozoic magmatic and metamorphic events in the Cuchilla Dionisio Terrane, Uruguay, and possible correlations across the South Atlantic
Neoproterozoic magmatic and metamorphic events in the Cuchilla Dionisio Terrane, Uruguay, and possible correlations across the South Atlantic
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乌拉圭库奇拉迪奥尼西奥地体的新元古代岩浆和变质事件以及整个南大西洋的可能相关性
DOI：
10.1016/j.precamres.2018.11.004
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发表时间：
2019
影响因子：
3.8
通讯作者：
Frimmel H E
中科院分区：
文献类型：
--
作者：
Will T M;Gaucher C;Ling X X;Li X H;Li Q L;Frimmel H E
乌拉圭东部Dom Feliciano带南部的Cuchilla Dionisio（或Punta del Este）地体经历了漫长的新元古代至寒武纪构造热演化。从地体基底（Cerro Olivo杂岩）的正长石和独居石年龄数据可以证明，在c. 780 Ma时存在广泛的岩浆活动，在655 - 632 Ma之间存在高品位的麻粒岩相变质作用。同位素数据表明，正长性原石器熔体形成于板块内与裂谷相关的环境中，是由新元古代从地幔中提取的下地壳物质（再）熔融形成的。我们的研究表明，地层向北延伸的距离比之前认为的要远。继承的中、古元古代锆石颗粒的存在表明地体中存在较古老的地壳成分。碎屑锆石颗粒的年龄及其Hf同位素特征不能用Río de la Plata克拉通的物源来解释，但与南部非洲喀拉哈里克拉通的物源一致。对原岩形成于埃迪卡拉系弧后盆地的Cuchilla Dionisio地块北部角闪岩中镁角闪石的Ar-Ar年龄分别为628和625 Ma。这些时代被解释为角闪岩相变质作用的时代。因此，喀拉哈里（或刚果？）和Río de la Plata克拉通之间的地壳收敛和其间的海洋盆地的俯冲一定是在655 - 625 Ma之间进行的。Cuchilla Dionisio Terrane的新元古代早期基底是非洲南部Namaqua省的一部分，该省在Rodinia分裂和Tonian南Adamastor洋的开放期间与卡拉哈里克拉通分离。该洋在低温世晚期至埃迪卡拉纪早期的闭合与弧岩浆作用和Cuchilla Dionisio地块基底的高温变质作用有关。弧后盆地在该弧与西非边缘之间形成并封闭。该盆地的遗迹在公元前625年 Ma被转移到Cuchilla Dionisio Terrane上。来自Cuchilla Dionisio和海岸地体的晚新元古代侵入火成岩位于超俯冲环境中（至少在乌拉圭），具有相同的Hf同位素特征。
The Cuchilla Dionisio (or Punta del Este) Terrane of the southern Dom Feliciano Belt, eastern Uruguay, experienced a prolonged Neoproterozoic to Cambrian tectonothermal evolution. Zircon and monazite age data from orthogneisses of the basement of the terrane (Cerro Olivo Complex) provide evidence of widespread magmatism at c. 780 Ma and high-grade, up to granulite-facies metamorphism between 655 and 632 Ma. Isotope data imply that the orthogneiss protolithic melts formed in a within-plate, rift-related setting by Neoproterozoic (re-) melting of lower crustal material that was extracted from the mantle during the Palaeoproterozoic. We show that the terrane extends further north than previously thought. The presence of inherited Meso- and Palaeoproterozoic zircon grains indicates the existence of older crustal components in the terrane. The ages of the detrital zircon grains and their Hf isotope signatures cannot be explained by a Río de la Plata Craton provenance but are consistent with a southern African Kalahari Craton origin. Ar-Ar ages of 628 and 625 Ma were obtained on magnesiohornblende in amphibolite from the northern Cuchilla Dionisio Terrane, whose protolith formed in an Ediacaran back-arc basin. These ages are interpreted as the time of amphibolite-facies metamorphism. Thus, crustal convergence between the Kalahari (or Congo?) and the Río de la Plata Craton and subduction of the intervening oceanic basin must have been underway between 655 and 625 Ma.The early Neoproterozoic basement of the Cuchilla Dionisio Terrane is part of the southern African Namaqua Province that was separated from the Kalahari Craton during Rodinia break-up and opening of the southern Adamastor Ocean in the Tonian. Closure of this ocean in the late Cryogenian to early Ediacaran was associated with arc magmatism and high-temperature metamorphism of the Cuchilla Dionisio Terrane basement. A back-arc basin formed and was closed between this arc and the western African margin. Relics of this basin were obducted onto the Cuchilla Dionisio Terrane at c. 625 Ma. Late Neoproterozoic intrusive igneous rocks from the Cuchilla Dionisio and the Coastal terranes were emplaced in a supra-subduction setting (at least in Uruguay) and have the same Hf isotope signature.
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影响因子：
1.8
作者：
R. C. Ramos;Edinei Koester;C. Porcher
通讯作者：
R. C. Ramos;Edinei Koester;C. Porcher
影响因子：
1.8
作者：
D. S. Oliveira;C. Sommer;R. Philipp;E. Lima;M. Basei
通讯作者：
D. S. Oliveira;C. Sommer;R. Philipp;E. Lima;M. Basei
影响因子：
3.8
作者：
T. Will;H. Frimmel;A. Zeh;P. Roux;E. Schmädicke
通讯作者：
T. Will;H. Frimmel;A. Zeh;P. Roux;E. Schmädicke
DOI：
10.1086/320795
发表时间：
2001-07
期刊：
The Journal of Geology
影响因子：
--
作者：
H. Frimmel;R. Zartman;Andreas Späth
通讯作者：
H. Frimmel;R. Zartman;Andreas Späth
影响因子：
2.3
作者：
C. Gaucher;R. Frei;F. Chemale;D. Frei;J. Bossi;G. Martínez;Leticia Chiglino;F. Cernuschi
通讯作者：
C. Gaucher;R. Frei;F. Chemale;D. Frei;J. Bossi;G. Martínez;Leticia Chiglino;F. Cernuschi