福建白垩纪红层火山岩夹层时代及构造意义 |
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引用本文: | 陈淑华,林慈銮,徐维光,赵骏杰. 福建白垩纪红层火山岩夹层时代及构造意义[J]. 地球科学, 2020, 45(7): 2508-2523. DOI: 10.3799/dqkx.2020.035 |
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作者姓名: | 陈淑华 林慈銮 徐维光 赵骏杰 |
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作者单位: | 福建省地质调查研究院, 福建福州 350013 |
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基金项目: | 中国地质科学院地质研究所台湾海峡两岸地质条件及地质系统图件编制DD20160345 |
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摘 要: | 为了研究福建省白垩纪红层形成的时代及构造背景,在政和-大埔断裂以西选取典型红层盆地,对不同盆地内火山岩夹层进行LA-ICP-MS锆石同位素定年和岩石地球化学分析.同位素U-Pb测年结果显示:沙县组的时限较长,为127~87 Ma,其总体时代应大致相当于晚白垩世早期,下部层段跨入早白垩世晚期;崇安组年龄为100.0±1.2 Ma,形成时代为晚白垩世早期.岩石地球化学结果表明,白垩纪红层中的火山岩为壳源成因,是处伸展环境下,为构造活动引起区域断陷拉张作用形成的一套钙碱性系列流纹岩.
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关 键 词: | 白垩纪 红层 火山岩 沙县组 构造学 |
收稿时间: | 2020-02-26 |
Age and Tectonic Significance of Volcanic Rocks in Cretaceous Red Beds in Fujian |
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Abstract: | In order to research the age and tectonic setting of the Cretaceous red beds in Fujian Province, typical red bed basins were selected on the west of the Zhenghe-Dapu fault, LA-ICP-MS zircon isotopic dating and rock geochemical analysis were performed on volcanic rocks in different basins. The results of zircon U-Pb isotopic dating show that the Shaxian Formation has a longer duration, which is 127-87 Ma, and its overall age should be roughly in early Late Cretaceous, and the lower part will enter the late Early Cretaceous. The age of the Chong'an Formation is 100.0±1.2 Ma, which is early Late Cretaceous. The results of petrochemical chemistry indicate that the volcanic rocks in the Cretaceous red beds are crust-originated and are a set of calcareous series rhyolites, which is in the extensional environment and formed by regional fault depression of tectonic activity. |
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