Detrital zircon U–Pb dating of low-grade metamorphic rocks in the Sulu UHP belt: evidence for overthrusting of the North China Craton onto the South China Craton during continental subduction
Detrital zircon U–Pb dating of low-grade metamorphic rocks in the Sulu UHP belt: evidence for overthrusting of the North China Craton onto the South China Craton during continental subduction
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DOI：
10.1144/0016-76492007-040
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发表时间：
2008-01
影响因子：
2.7
通讯作者：
Jian‐Bo Zhou;S. Wilde;Guochun Zhao;Changqing Zheng;W. Jin;Xingzhou Zhang;Hongjiang Cheng
中科院分区：
文献类型：
--
作者：
Jian‐Bo Zhou;S. Wilde;Guochun Zhao;Changqing Zheng;W. Jin;Xingzhou Zhang;Hongjiang Cheng
在中国中东部的苏鲁超高压带中，零星出露有石桥-坪上浅变质沉积岩。常量和微量元素数据表明，它们可能是在华北陆缘的一个被动陆缘盆地中沉积的。对坪上石英岩（SD 53）和石桥石英片岩（SD 54）的碎屑锆石进行了高分辨离子探针（SHRIMP）U-Pb定年，年龄为2800 ~ 1900 Ma。三个年龄群体被定义为：2660-2500，2350-2150和2100-1900 Ma，峰值年龄分别为2522，2212和2020 Ma。石英片岩（SD 54）的白云母Ar-Ar年龄为265.9 ± 1.2Ma。这些资料支持石桥坪上浅变质沉积岩起源于华北陆块，并在二叠纪经历了华南陆块（扬子陆块）向华北陆块俯冲的变形。这就要求低品位的变质沉积岩被逆冲推覆到华南造山带上数十公里，解释了为什么华北造山带的物源在毗邻大别-苏鲁造山带的三叠纪-侏罗纪沉积盆地中很常见。
The Shiqiao–Pingshang low-grade metasedimentary rocks sporadically crop out in the Sulu ultrahigh-pressure (UHP) belt in east–central China. Major and trace element data indicate that they were deposited in a passive margin basin, probably located at the southern margin of the North China Craton. Sensitive high-resolution ion microprobe (SHRIMP) U–Pb dating of detrital zircons from a quartzite (SD53) from Pingshang and a quartz schist (SD54) from Shiqiao records ages ranging from 2800 to 1900 Ma. Three age populations are defined: at 2660–2500, 2350–2150 and 2100–1900 Ma, with peak ages at 2522, 2212 and 2020 Ma, respectively. Muscovite Ar–Ar dating of the quartz schist (SD54) yields a plateau age of 265.9 ± 1.2 Ma. These data support the view that the Shiqiao–Pingshang low-grade metasedimentary rocks originated from the North China Craton, and underwent deformation in the Permian during subduction of the South China Craton (Yangtze block) beneath the North China Craton. This requires that the low-grade metasedimentary rocks were overthrust for several tens of kilometres onto the South China Craton, explaining why source materials from the North China Craton are common in Triassic to Jurassic sedimentary basins adjacent to the Dabie–Sulu orogenic belt.