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| 1 | Zircon U-Pb SHRIMP dating for the volcanic rocks of the Xiong’er Group: Constraints on the initial formation age of the cover of the North China Craton显示文摘The volcanic rocks of the Xiong'er Group occur widely in the southern part of the North China Craton, which mark the beginning of the cover in the southern part of the North China Craton. The age of the volcanic rocks is thus crucial to understand the tectonic regime and evolutionary history of the North China Craton in the Proterozoic age. Zircons from five volcanic rocks and intrusions were dated by U-Pb SHRIMP method. The results indicate that the Xiong'er Group formed in 1.80--1.75 Ga of Paleo-Proterozoic. Since the Xiong'er Group formed earlier than the Changcheng System, the earliest rocks in the Changcheng System is therefore assumed to be formed in 1.75 Ga. A thermal-tectonic event of ca. 1.84 Ga is indicated by new zircon U-Pb SHRIMP ages in the southern part of the North China Craton. The volcanic rocks of the Xiong'er Group thus represent the initial magmatism of the Paleo-Proterozoic breakup of the North China Craton. Numerous inherited zircons in the volcanic rocks mainly formed in ~2.20 Ga, indicating that the source magma of the volcanic rocks may be derived from the ~2.20 Ga crust, or from a mantle magma with significant contamination of the ~2.20 Ga crust. | ZHAOTaiping ZHAIMingguo XIABin LIHuimin ZHANGYixing WANYusheng | 2004 | Chinese Science Bulletin2004，49，23： | 84 |
| 2 | Mineralizing age of the Rushan lode gold deposit in the Jiaodong Peninsula:SHRIMP U-Pb dating on hydrothermal zircon显示文摘Zircons from the auriferous quartz vein in the Rushan gold deposit, Jiaodong Peninsula, have high common Pb contents (206Pbc = 2.00%—15.88%) and Th/U ratios (0.31—1.35), and trap primary CO2-H2O fluid inclusion similar to ore-forming fluids, indicating that they grew from high Th/U ratio ore-forming fluids responsible for gold min- eralization. SHRIMP U-Pb analyses of these zircons gave an age of 117±3 Ma comparable with the ages reported by the former researches in the other areas in the Jiaodong Penin- sula, which is interpreted as the age of gold mineralization at Rushan. The age of SHRIMP zircon U-Pb dating with 160±3 Ma from host rock Kunyushan monzogranite is different from that of the gold mineralization, indicating that there is no genetic relationship between gold mineralization and the granitic magmatism. SHRIMP U-Pb dating on hydrothermal zircons from auriferous quartz veins could be used to con- strain the timing of lode gold mineralization and the rela- tionship to relevant hydrothermal event. | HUFangfang FANHonarui YANGJinhui WANYusheng LIUDunyi ZHAIMingguo JINChengwei | 2004 | Chinese Science Bulletin2004，49，15： | 79 |
| 3 | SHRIMP ages of detrital zircons from the Changcheng System in the Ming Tombs area,Beijing:Constraints on the protolith nature and maximum depositional age of the Mesoproterozoic cover of the North China Craton显示文摘The Mesoproterozoic Changcheng System is widely distributed in the North China Craton. Determining its time of deposition and sources is important to understand the Precambrian crustal evolution of the North China Craton. This paper suggests age distribution patterns for detrital zircons from clastic sediments of the Changcheng System in the Ming Tombs area, Beijing. Samples of feldspar-bearing sandstone (CHc-2) and pure sandstone (CHc-9) were collected from the Changzhougou Formation, which constitutes the basal part of the Changcheng System. Detrital zircons show an age range from 2.35 to 2.60 Ga. However, sample CHc-9 in the upper Changzhougou Formation also contains some zircons with ages of 1.9-1.8 Ga and 2.3-2.1 Ga. The age patterns lead to the following conclusions: (1) Most of the detrital material came from a source area composed predominantly of ~2.5 Ga continental crust of the North China Craton; (2) 1.9-1.8 Ga reflects the age record of Palaeoproterozoic continent-continent collisional event in the North China Craton; and (3) the oldest age for deposition of the Changcheng System is 1.8 Ga. | WAN Yusheng1,2, ZHANG Qiaoda1 & SONG Tianrui1 1. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 2. Beijing SHRIMP Laboratory, Beijing 100037, China Correspondence should be addressed to Wan Yusheng (e-mail: wanyusheng@cags.net.cn) | 2003 | Chinese Science Bulletin2003，48，22： | 60 |
| 4 | SHRIMP U-Pb zircon geochronology of granulites at Rimana(Southern Tibet)in the central segment of Himalayan Orogen显示文摘High-pressure mafic granulites, occurring as lenses within gneisses and quartzite in the central segment of the Himalayan orogen, were dated using SHRIMP U-Pb technique. 13 analyses out of a total of 15 are plotted along a concordia line and yield a mean 206Pb/238U age of 17.6 0.3 Ma. This age indicates adiabatic decompression and a metamorphic event associated with rapid uplift of granulites in a tectonic environment resulted from the collision between India and Eurasia, synchronous with large-scale thrusting, extension, detachment as well as emplacement of leu-cogranite. One analysis gives a 206Pb/238U age of 29.5 0.4 Ma that is interpreted to represent the timing of the final closure of the Neo-Tethys. Another age is 1991 26 Ma that represents the age of the protolith of the granulites. In sum-mary, dating results show that granulites in this area under-went multiphase metamorphism and complex geological evolution. | LIDewei LIAOQunan YUANYanming WANYusheng LIUDemin ZHANGXionghua YIShunhua CAOShuzhao XlEDefan | 2003 | Chinese Science Bulletin2003，48，23： | 11 |
| 5 | Comparison of SHRIMP U-Pb dating of monazite and zircon显示文摘Monazite dating is an important technique in geochronological studies. However, monazite U-Pb dating by SHRIMP is much less popular than zircon in geochronologi-cal applications. This paper compares the results of SHRIMP U-Pb dating of monazites and zircons separated from two granite samples, indicating that monazite SHRIMP U-Pb dating at the Beijing SHRIMP Centre is feasible and pro-vides identical results within error. | WANYusheng LIUDunyi JIANPing | 2004 | Chinese Science Bulletin2004，49，14： | 10 |
| 6 | 祁连南缘花岗岩和榴辉岩之间的关系:嗷唠山花岗岩SHRIMP锆石年龄证据显示文摘祁连南缘嗷唠山花岗岩锆石的SHRIMP年龄变化于445~496Ma之间,平均为 473 Ma,属早奥陶世。年龄值的统计出现两个峰值,第一个峰值与区内榴辉岩的相同(495 Ma),可能反映花岗岩源岩的部分熔融时代,第二个年龄峰值可能反映了花岗质岩浆的冷凝结晶时代(465 Ma)。该花岗岩的岩石地球化学特征类似于Ⅰ型花岗岩,有关构造环境判别图解得出,该花岗岩类似于岛弧或活动陆缘环境。结合区域地质特征和花岗岩的锆石SHRIMP年龄特征,我们认为。 | 吴才来 Jone WOODEN 杨经绥 李海兵 TrevorIRELAND LIOUJuneGuang WanYusheng 史仁灯 | 2002 | 地质学报2002，76，1： | 5 |
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