K‐Ar Geochronology of Mesozoic Mafic Dikes in Shandong Province, Eastern China: Implications for Crustal Extension
K‐Ar Geochronology of Mesozoic Mafic Dikes in Shandong Province, Eastern China: Implications for Crustal Extension
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DOI：
10.1111/j.1755-6724.2004.tb00777.x
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发表时间：
2004-12
期刊：
影响因子：
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通讯作者：
Liu Shen;Hu Rui-zhong;Z. Junhong;Feng Caixia
中科院分区：
文献类型：
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作者：
Liu Shen;Hu Rui-zhong;Z. Junhong;Feng Caixia
基于K - Ar同位素分析，山东西部和东部中生代基性（和碱超基性）岩脉的年龄为88.2±1.70 Ma ~ 169.5±3.7 Ma，大部分年龄在90 ~ 140 Ma之间。这些岩脉的侵位反映了山东省燕山期（白垩纪）地壳的一次大伸展。结合已有的年龄资料，本研究提出了四个时期的地壳伸展，分别在80 Ma、100 Ma、120 Ma和140 Ma左右。除了燕山造山带在白垩纪对山东基性岩脉侵位的影响外，地幔柱和郯庐断裂的广泛左侧平流伸展也分别控制了鲁东和鲁西地区的地壳伸展和基性岩脉侵位。
Abstract Based on K‐Ar isotope analyses, Mesozoic mafic (and alkali ultramafic) dikes from western and eastern Shandong Province, China, are dated at 88.2±1.70 Ma to 169.5±3.7 Ma with the majority of ages ranging from 90 Ma to 140 Ma. The emplacement of the dikes suggests a major Yanshanian (Cretaceous) crustal extension in Shandong province. Together with other available age data, this study suggests four periods of crustal extension at about 80 Ma, 100 Ma, 120 Ma and 140 Ma, respectively. Besides the effect of collapse of the Yanshanian orogenic belt on the emplacement of the mafic dikes in Shandong in the Cretaceous, the mantle plume and the extensive left‐lateral advection and extension of the Tanlu fault also have controlled the crustal extension and the emplacement of the mafic dikes in eastern Shandong and western Shandong, respectively.