Neoproterozoic to Early Palaeozoic events in the Sierra de San Luis: implications for the Famatinian geodynamics in the Eastern Sierras Pampeanas (Argentina)
Neoproterozoic to Early Palaeozoic events in the Sierra de San Luis: implications for the Famatinian geodynamics in the Eastern Sierras Pampeanas (Argentina)
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圣路易斯山脉新元古代至早古生代事件：对潘皮纳斯山脉东部法马提尼亚地球动力学的影响（阿根廷）
DOI：
10.1144/0016-76492005-064
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发表时间：
2006
影响因子：
2.7
通讯作者：
K. Wemmer
中科院分区：
文献类型：
--
作者：
A. Steenken;S. Siegesmund;M. G. López de Luchi;R. Frei;K. Wemmer
利用高分辨率离子探针（SHRIMP） U/Pb测年技术对圣路易山不同岩石类型的锆石和单氮石进行测年，为研究沉积前体物源和沉积时间以及不同基底域的变质和火成岩历史提供了重要依据。另外，通过对1个橄榄石和2个石榴石分选物进行Pb/Pb分级浸出试验，对发马期变质期进行了进一步的约束。结果表明，康lara变质杂岩的沉积前体的最大年龄为c. 590 Ma，而Pringles变质杂岩的沉积前体似乎来自早寒武世的Pampean造山带。c. 496 Ma El Peñón岩体内的折叠包体表明寄主Conlara变质杂岩经历了潘培亚挤压。从Nogolí变质杂岩中混杂岩的208Pb/232Th单脱石年龄（478 Ma）来看，该基底杂岩的构造演化完全是后潘泛世的。法马梯纪高变质作用发生于约500 Ma至450 Ma之间，是冈瓦纳板块西外侧的地壳伸展期，可能与中奥陶统的古尼亚地体增生没有直接关系。
The application of the sensitive high-resolution ion microprobe (SHRIMP) U/Pb dating technique to zircon and monazites of different rock types of the Sierra de San Luis provides an important insight into the provenance and timing of deposition of the sedimentary precursors as well as the metamorphic and igneous history of the various basement domains. Additional constraints on the Famatinian metamorphic episode are provided by Pb/Pb stepwise leaching experiments on one staurolite and two garnet separates. The results indicate that the sedimentary precursors of the Conlara Metamorphic Complex have a maximum age of c. 590 Ma, whereas the Pringles Metamorphic Complex metasediments appear to be sourced from the Pampean orogen in the Early Cambrian. Folded xenoliths within the c. 496 Ma El Peñón pluton suggest that the host Conlara Metamorphic Complex underwent a Pampean compression. From a 208Pb/232Th monazite age of 478 Ma for a migmatite from the Nogolí Metamorphic Complex, the structural evolution of this basement complex appears to be entirely post-Pampean. Onset of the Famatinian high-grade metamorphism, between c. 500 Ma and c. 450 Ma, follows a period of crustal extension on the western outboard of Gondwana and might not be related directly to a Mid-Ordovician accretion of the Cuyania Terrane.