Abstract

The Early Neoproterozoic (851 ± 4 Ma) age of the bimodal basalt-rhyolite volcanic series, exposed on the southern slope of the Talas Alatau Range of northwest Kyrgyzstan, was established by U–Th–Pb (SHRIMP) zircon dating. High concentrations of titanium, iron, and phosphorus in basalts, as well as the distribution of trace elements, similar to those in the OIB, indicate intraplate tectonic settings of volcanism. Revealed magmatic episode corresponds to the earliest stages of continental break-up of Rodinia. New age suggests that rifting in the marginal parts of Rodinia in the northwest Tianshan likely started 10–20 Ma earlier than in the internal areas of the supercontinent.

中文翻译：

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北天山塔拉斯山脉的新元古代早期（约850 Ma）双峰火山系列：罗迪尼亚大陆解体最早阶段的指示

摘要

通过U–Th–Pb（SHRIMP）锆石测年建立了双峰玄武岩-流纹岩火山系列的新元古代早期（851±4 Ma）年龄，暴露于吉尔吉斯斯坦西北部的塔拉斯阿拉托山脉的南坡。玄武岩中高浓度的钛，铁和磷以及微量元素的分布与OIB中的相似，表明火山活动的板块内构造环境。揭示的岩浆事件对应于罗迪尼亚大陆破裂的最早阶段。新时代表明，天山西北部罗迪尼亚边缘地区的裂谷作用可能比超大陆内部地区早10-20 Ma。