辽东半岛位于华北克拉通东部、苏鲁超高压造山带的北部(图1(a)).该区分布着大面积的花岗岩类侵入体(图1(b)),经过我们近几年的锆石U-Pb年代学详细研究表明,它们主要形成于侏罗纪(180～153 Ma)和早白垩世(131～118 Ma)(吴福元等,2005... 辽东半岛位于华北克拉通东部、苏鲁超高压造山带的北部(图1(a)).该区分布着大面积的花岗岩类侵入体(图1(b)),经过我们近几年的锆石U-Pb年代学详细研究表明,它们主要形成于侏罗纪(180～153 Ma)和早白垩世(131～118 Ma)(吴福元等,2005;Wu et al.,2005a,b;Yang et al.,2004a,2006,2007).……展开更多
A felsic tuffaceous rock, obtained from a metamorphosed sequence of volcanics and sediments of the Hutuo Group, 8 km south of Taihuai in Wutaishan, contains two zircon populations. These record SHRIMP ^207Pb/^206Pb we...A felsic tuffaceous rock, obtained from a metamorphosed sequence of volcanics and sediments of the Hutuo Group, 8 km south of Taihuai in Wutaishan, contains two zircon populations. These record SHRIMP ^207Pb/^206Pb weighted mean ages of 2180 ± 5 Ma and 2087 ± 9 Ma, respectively. The older date is within error of the age of the Dawaliang Granite in Wutaishan and is considered to be derived from a similar crustal magmatic source. The younger date is within error of reported ages from metasediments and meta-volcanics of the Wanzi supracrustal rocks and the Nanying granitic gneisses in the adjacent Fuping Complex and is interpreted to be the age of volcanism in the Hutuo Group. These data establish that: (1) the Hutuo Group is Paleoproterozoic and not Archean in age and (2) the volcanism and sedimentation were coeval in the Wutai and Fuping complexes. Sedimentation was therefore widespread at this time and possibly reflects deposition along an evolving continental margin, most likely the western margin of the Eastern Block of the North China Craton. The age of 2087±9 Ma for volcanism in the Hutuo Group means that it must have been deformed and metamorphosed after this time.This further supports the evidence, obtained from other recent studies, that the main tectonism in the Wutaishan areaoccurred at ～1.8 Ga during the Lüliang orogeny. This orogeny resulted in the collision of the Eastern and Western blocks of the North China Craton and formed part of a global supercontinental amalgamation event.展开更多
Analysis using the Sensitive High Resolution Ion Microprobe (SHRIMP) shows that the Yongsheng pluton, located to the south of Huadian County, Jilin Province, in the North China Craton, has a zircon U-Pb isotopic empla...Analysis using the Sensitive High Resolution Ion Microprobe (SHRIMP) shows that the Yongsheng pluton, located to the south of Huadian County, Jilin Province, in the North China Craton, has a zircon U-Pb isotopic emplacement age of (31.6±1.3) Ma. It is therefore the youngest exposed pluton so far recognized in eastern China. Although geochemical data indicate intensive crystal fractionation, the Sr-Nd isotopic features suggest that the magmatic source region of the lithospheric mantle was weakly depleted. This implies that the previous enriched lithospheric mantle had been replaced by juvenile asthenospheric mantle before or during the Palaeogene. This recognition has great significance for future work on the Mesozoic-Cenozoic geological evolution and deep geological processes in eastern China.展开更多
The global collisional orogenic events (e.g. Grenvil-lian or Pan-African event) have occurred for several times since 2.5 billion years (Ga) ago, which has led Earth scientists to speculate that continental landmasses...The global collisional orogenic events (e.g. Grenvil-lian or Pan-African event) have occurred for several times since 2.5 billion years (Ga) ago, which has led Earth scientists to speculate that continental landmasses have periodically assembled and dispersed, resulting in the assembly and breakup of supercontinent. In the last decade, the reconstruction of ancient supercontinents has been focused on Rodinia, a defined supercontinent that was assembled along the -1.0 Ga "Grenvillian" oro-gens. In reconstructing Rodinia, however, Earth scientists have noticed that not all continental blocks in the supercontinent were welded by the -1.0 Ga orogenic belts (fig. 1(a)), and that most blocks welded by the 1.0 Ga orogens contain abundant evidence that they are a展开更多
文摘 辽东半岛位于华北克拉通东部、苏鲁超高压造山带的北部(图1(a)).该区分布着大面积的花岗岩类侵入体(图1(b)),经过我们近几年的锆石U-Pb年代学详细研究表明,它们主要形成于侏罗纪(180～153 Ma)和早白垩世(131～118 Ma)(吴福元等,2005;Wu et al.,2005a,b;Yang et al.,2004a,2006,2007).……
文摘A felsic tuffaceous rock, obtained from a metamorphosed sequence of volcanics and sediments of the Hutuo Group, 8 km south of Taihuai in Wutaishan, contains two zircon populations. These record SHRIMP ^207Pb/^206Pb weighted mean ages of 2180 ± 5 Ma and 2087 ± 9 Ma, respectively. The older date is within error of the age of the Dawaliang Granite in Wutaishan and is considered to be derived from a similar crustal magmatic source. The younger date is within error of reported ages from metasediments and meta-volcanics of the Wanzi supracrustal rocks and the Nanying granitic gneisses in the adjacent Fuping Complex and is interpreted to be the age of volcanism in the Hutuo Group. These data establish that: (1) the Hutuo Group is Paleoproterozoic and not Archean in age and (2) the volcanism and sedimentation were coeval in the Wutai and Fuping complexes. Sedimentation was therefore widespread at this time and possibly reflects deposition along an evolving continental margin, most likely the western margin of the Eastern Block of the North China Craton. The age of 2087±9 Ma for volcanism in the Hutuo Group means that it must have been deformed and metamorphosed after this time.This further supports the evidence, obtained from other recent studies, that the main tectonism in the Wutaishan areaoccurred at ～1.8 Ga during the Lüliang orogeny. This orogeny resulted in the collision of the Eastern and Western blocks of the North China Craton and formed part of a global supercontinental amalgamation event.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 49872031) and Jilin Excellent Youth Fund.
文摘Analysis using the Sensitive High Resolution Ion Microprobe (SHRIMP) shows that the Yongsheng pluton, located to the south of Huadian County, Jilin Province, in the North China Craton, has a zircon U-Pb isotopic emplacement age of (31.6±1.3) Ma. It is therefore the youngest exposed pluton so far recognized in eastern China. Although geochemical data indicate intensive crystal fractionation, the Sr-Nd isotopic features suggest that the magmatic source region of the lithospheric mantle was weakly depleted. This implies that the previous enriched lithospheric mantle had been replaced by juvenile asthenospheric mantle before or during the Palaeogene. This recognition has great significance for future work on the Mesozoic-Cenozoic geological evolution and deep geological processes in eastern China.
基金This work was supported by Hong Kong RGC (Grant Nos. HKU7115/00P and HKU7090/01P) the National Natural Science Foundation of China (Grant No. 40072061).
文摘The global collisional orogenic events (e.g. Grenvil-lian or Pan-African event) have occurred for several times since 2.5 billion years (Ga) ago, which has led Earth scientists to speculate that continental landmasses have periodically assembled and dispersed, resulting in the assembly and breakup of supercontinent. In the last decade, the reconstruction of ancient supercontinents has been focused on Rodinia, a defined supercontinent that was assembled along the -1.0 Ga "Grenvillian" oro-gens. In reconstructing Rodinia, however, Earth scientists have noticed that not all continental blocks in the supercontinent were welded by the -1.0 Ga orogenic belts (fig. 1(a)), and that most blocks welded by the 1.0 Ga orogens contain abundant evidence that they are a
