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| 1 | Zircon U-Pb geochronological framework of Qitianling granite batholith, middle part of Nanling Range, South China显示文摘The Qitianling granite batholith (QGB) is located in the southern Hunan Province, middle part of the Nanling Range, South China. Its total exposure area is about 520 km2. Based on our 25 single grain zircon U-Pb age data and 7 published data as well as the geological, petrological, and space distribution characteristics, we conclude that QGB is an Early Yanshanian (Jurassic) multi-staged composite pluton. Its formation process can be subdivided into three major stages. The first stage, emplaced at 163―160 Ma with a peak at about 161 Ma, is mainly composed of hornblende-biotite monzonitic granites and locally biotite granites, and distributed in the eastern, northern, and western peripheral parts of the pluton. The second stage, emplaced at 157―153 Ma with a peak at 157―156 Ma, is mainly composed of biotite granites and locally containing hornblende, and distributed in the middle and southeastern parts of the pluton. The third stage, emplaced at 150―146 Ma with a peak at about 149 Ma, is mainly composed of fine-grained (locally porphyritic) biotite granites, and distributed in the middle-southern part of the pluton. Each stage can be further disintegrated into several granite bodies. The first two intrusive stages comprise the major phase of QGB, and the third intrusive stage comprises the additional phase. Many second stage fine-grained granite bosses and dykes intruded into the first stage host granites with clear chilling margin-baking phenomena at their intrusive contacts. They were emplaced in the open fracture space of the earlier stage consolidated rocks. Their isotopic ages are mostly 2―6 Ma younger than their hosts. Conceivably, the time interval from magma emplacement, through cooling, crystallization, solidification, up to fracturing of the earlier stage granites cannot exceed 2―6 Ma. During the Middle-Late Jurassic in the Qitianling area and neighboring Nanling Range, the coeval granitic and basic-intermediate magmatic activities were widely developed. It indicates that the Early Yanshanian period was the culmination time of magmatic activities in this region. The Nanling Range was under a post-orogenic, intracontinental geotectonic environment with an obvious lithospheric extension and thinning. The crust-mantle interaction played an important role in formation of granitic rocks in this region. | ZHU JinChu WANG RuCheng ZHANG PeiHua XIE CaiFu ZHANG WenLan ZHAO KuiDong XIE Lei YANG Ce CHE XuDong YU APeng WANG LuBin | 2009 | Science China Earth Sciences2009，52，9： | 27 |
| 2 | Identification of Hercynian shoshonitic intrusive rocks in central Hainan Island and its geotectonic implications显示文摘An identification has been made of some shoshonitic intrusive rocks in central Hainan Island recently. These rocks are K-rich (K2O=2.9%―5.1%, K2O/Na2O=0.95―2.12), distinctly enriched in LILE and LREE, strongly depleted in Nb, Ta, and moder- ately depleted in Sr and Ti, with (87Sr/86Sr)i = 0.70859―0.71425 and ε Nd(t) = (?2.77―?7.49). They were derived from an EMⅡ-type mantle source. The enrichment process is related to metasomatism of depleted mantle caused by a great amount of fluid-melt released from oceanic crust and terri- genous sediments at great depth (eclogite facies) during the subduction of the South China plate under the Indochina-South China Sea plate in the Carbon- iferous–Early Permian. A SHRIMP U-Pb zircon dating yields a crystallization age of 272±7 Ma for the sho- shonitic intrusions, which is coeval with the strongly peraluminous granites found in central Hainan Island. These two kinds of rocks generally possess syn-intrusion ductile deformation structures. Thus they are considered to have been generated during the early stage (syn-thrust phase) of a post-collisional event. The primary magma of shoshonitic rocks was produced at a depth > 80 km by decompression- dehydration melting of previously enriched litho- spheric mantle wedge, phlogopite-bearing garnet peridotite, which was in turn caused by the break-off of a descendent slab and upwelling of a hot as- thenosphere. The rising of melts was accompaniedby crustal contamination and crystallization fractiona- tion (AFC). Combining with other related data, it is proposed that the southwards subduction and amal- gamation of the South China plate with the Indo- China-South China Sea plate took place at ca. 287- 278 Ma, which was a part of the convergence proc- ess of the Pangea supercontinent. The suture zone was probably located along the line of Song Ma-Beibu Gulf-north margin of the Yunkai Moun- tains-Wuyi Mountains. | XIE Caifu ZHU Jinchu DING Shijiang ZHANG Yeming FU Tai'an LI Zhihong | 2006 | Chinese Science Bulletin2006，51，20： | 17 |
| 3 | Genesis of Highly Fractionated I-Type Granites from Fengshun Complex:Implications to Tectonic Evolutions of South China显示文摘The South China Block is characterized by the large-scale emplacement of felsic magmas and giant ore deposits during the Yanshanian. We present zircon Hf isotopic compositions, whole-rock major and trace element compositions of the Fengshun complex, located in eastern Guangdong Province, South China. The Fengshun complex is a multi-stage magmatic intrusion. It is composed of two main units, i.e., the Mantoushan(MTS) syeno-monzogranites, alkali feldspar granites and the Hulutian(HLT) alkali feldspar granites. LA-ICPMS zircon dating shows that the complex emplaced in 166–161 and 139±2 Ma, respectively. Geochemically, the MTS granites show relatively various geochemical compositions with low REE contents(87.76×10^(-6)–249.71×10^(-6)), Rb/Sr ratios(1.19–58.93), pronounced Eu negative anomaly(0.01–0.37) and low Nb/Ta ratios(2.40–6.82). In contrast, the HLT granites exhibit relatively stable geochemical characteristics with high REE contents(147.35×10^(-6)– 282.17×10^(-6)), Rb/Sr ratios(2.05–10.30) and relatively high Nb/Ta ratios(4.45–13.00). The isotopic data of the MTS granites display relatively enriched values, with I_(Sr) varying from 0.708 2 to 0.709 7, εNd(t) from-7.8 to-6.9 and εHf(t) from-7.4 to-3.2, in comparison with those of the HLT which are I_(Sr)=0.703 05–0.704 77, εNd(t)=-5–-3.4 and εHf(t)=-0.7–1.8). The two-stage model ages of the MTS granites(T_(2DM)(Nd)=1.51–1.59 Ga and T_(2DM)(Hf)=1.26–1.48 Ga) are also higher than those of the HLT granites(T_(2DM)(Nd)=1.21–1.34 Ga and T_(2DM)(Hf)=0.96–1.10 Ga). Thus the MTS and HLT granites might originate from different sources. The former is more likely derived from partial melting of Meso-Proterozoic basement triggered by upwelling of asthenosphere and/or underplate of the basaltic magma and then extensive fractional crystallisation, similar to the genesis of Early Yanshanian granitoids of the EW-trending tectono-magmatism belt in the Nanling range. In comparison, the latter might have involved with asthenosphere component, similar to the Early Cretaceous granitoids of NE-NNE-trending granitoid-volcanic belt in coastal region, southeastern China. We propose that the MTS granites were mainly formed in Paleo-Tethyan post-orogenic extensional tectonic setting whereas the HLT granites were formed in the back-arc extensional tectonic setting. The period at 139 Ma represents the initial time of roll-back of the paleo-Pacific Plate in SE-trending. | Zuomin Zhou Changqian Ma Caifu Xie Lianxun Wang Yuanyuan Liu Wei Liu | 2016 | Journal of Earth Science2016，27，3： | 11 |
| 4 | Timing of Metamorphism and Provenance of the Metamorphic Basement of the Xiangshan Uranium Orefield, Jiangxi Province, China显示文摘The origin, age and evolution of the Precambrian metamorphic basement of southern China provide useful insights into early crustal development. Here, we present new laser ablation–inductively coupled plasma–mass spectrometry(LA–ICP–MS) U–Pb age data for detrital zircons from five samples of the Precambrian metamorphic basement of the Xiangshan uranium orefield. Two of these samples, from the northern Xiangshan volcanic basin, yielded a total of 140 U–Pb ages that cluster within the Neoproterozoic(773–963 Ma; 79.3% of data points), with the rest being scattered through the Paleoproterozoic and Mesoproterozoic, along with a single Archean age. These ages indicate that this basement material is associated with the Cathaysia Block. In comparison, the 172 concordant ages from the other three samples from the southern part of the Xiangshan volcanic basin cluster within the Neoproterozoic(767–944 Ma; 59.8%) as well as the Proterozoic(37.8%) and the Archean(2502–2712 Ma; 14.5%). These samples are also free of zircons with Grenvillian ages, indicating that these units are associated with the southeastern Yangtze Block. Combining these data with the geochemistry of these units, which suggests that the metamorphosed sedimentary rocks within the northern and southern parts of the Xiangshan basin have a common component from a magmatic island arc that formed during the early Neoproterozoic, we infer that the basin was located along the boundary between the Cathaysian and Yangtze blocks. In addition, the zircons within the samples from the southern and northern parts of the Xiangshan basin show different pre-Neoproterozoic(963 Ma) age populations but similar postNeoproterozoic zircon populations, indicating that the amalgamation of the Cathaysian and Yangtze blocks occurred after the Neoproterozoic(960 Ma), with magmatism peaking at 830 Ma and rifting starting at ~770 Ma, leading to the subsequent deposition(from bottom to top) of the Shenshan, Kuli, and Shangshi formations. | GUO Fusheng SHI Guo YANG Qingkun ZHANG Wanliang XIE Caifu ZHOU Wanpeng ZHANG Jiewei | 2018 | Acta Geologica Sinica(English Edition)2018，92，1： | 6 |
| 5 | Where are the Volcanic Calderas in the Xiangshan Volcanic Basin of Jiangxi? Implications from Anisotropy of Magnetic Susceptibility显示文摘Objective As the world's third largest volcanic type uranium ore field,the Xiangshan volcanic basin has attracted much attention for its large industrial value.The ore hosting rocks are mainly the early Cretaceous rhyodacite and porphyroclastic lava,as well as small amounts of high level intrusive acidic rocks and metamorphic rocks.The vertical alteration of polymetallic | GUO Fusheng LI Guangrong LIU Linqing WU Zhichun YANG Qingkun XIE Caifu | 2017 | Acta Geologica Sinica(English Edition)2017，91，1： | 2 |
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