U-Pb SHRIMP ages of detrital zircons from Hiriyur Formation in Chitradurga greenstone belt and its implication to the Neoarchean evolution of Dharwar craton, south India
U-Pb SHRIMP ages of detrital zircons from Hiriyur Formation in Chitradurga greenstone belt and its implication to the Neoarchean evolution of Dharwar craton, south India
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DOI：
10.1007/s12594-016-0372-2
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发表时间：
2016-01
影响因子：
1.3
通讯作者：
A. Nasheeth;T. Okudaira;K. Horie;T. Hokada;M. Satish-Kumar
中科院分区：
文献类型：
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作者：
A. Nasheeth;T. Okudaira;K. Horie;T. Hokada;M. Satish-Kumar
本文报道了采自Chitradurga绿岩带中东部的Hiriyur组（Chitradurga群，Dharwar超群）变质杂岩体中碎屑锆石的SHRIMP U-Pb年龄。U-Pb分析产生了三个主要的新太古代年龄群体，范围从2.70-2.54 Ga与一些次要的中太古代年龄群体。沉积的最大年龄是由最年轻的碎屑锆石人口在2546马。这是首次报道在奇特拉杜尔加绿岩带中部发现小于2.58Ga的表壳岩。碎屑年龄与周围的火成岩公布的年龄密切的评价表明，最年轻的碎屑锆石可能来自东部的Dharwar克拉通和推断对接的西部和东部Dharwar克拉通的岩石发生在Hiriyur组的沉积之前。Chitradurga剪切带，将Dharwar克拉通分为西部和东部块体，可能在沉积后发展。此外，较低的截距被解释为研究区域泛非叠印的证据。
We report newly obtained U-Pb SHRIMP ages of detrital zircons from metagreywackes in the Hiriyur Formation (Chitradurga Group, Dharwar Supergroup) from the central eastern part of the Chitradurga greenstone belt. U-Pb analyses yield three major Neoarchean age populations ranging from 2.70–2.54 Ga with some minor age population of Mesoarchean. The maximum age of deposition is constrained by the youngest detrital zircon population at 2546 Ma. This is the first report of the occurrence of supracrustal rocks less than 2.58 Ga in the central part of Chitradurga greenstone belt. Close evaluation of detrital ages with the published ages of surrounding igneous rocks suggest that the youngest detrital zircons might be derived from rocks of the Eastern Dharwar craton and the inferred docking of the western and eastern Dharwar cratons happened prior to the deposition of the Hiriyur Formation. The Chitradurga shear zone, dividing the Dharwar craton into western and eastern blocks, probably developed after the deposition. Furthermore, the lower intercept is interpreted as evidence for the Pan-African overprints in the study area.