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| 1 | Petrogenesis of highly fractionated I-type granites in the Zayu area of eastern Gangdese, Tibet: Constraints from zircon U-Pb geochronology, geochemistry and Sr-Nd-Hf isotopes显示文摘The Cretaceous granitoids in the middle and northern Gangdese, Tibet are generally interpreted as the products of anatexis of thickened deep crust genetically associated with the Lhasa-Qiangtang collision. This paper reports bulk-rock major element, trace element and Sr-Nd isotopic data, zircon U-Pb age data, and zircon Hf isotopic data on the Zayu pluton in eastern Gangdese, Tibet. These data shed new light on the petrogenesis of the pluton. Our SHRIMP zircon U-Pb age dates, along with LA-ICPMS zircon U-Pb age dates recently reported in the literature, indicate that the Zayu pluton was emplaced at about 130 Ma, coeval with Early Cretaceous magmatic rocks in other areas of eastern Gangdese (e.g., Rawu, Baxoi areas) and the Middle Gangdese. The Zayu pluton samples lack amphibole and muscovite, and are compositionally characterized by high SiO2 (69.9%―76.8%), K2O (4.4%―5.7%), and low P2O5 (0.05%―0.12%). These samples also have A/CNK values of 1.00-1.05, and are enriched in Rb, Th, U, and Pb, and depleted in Ba, Nb, Ta, Sr, P, Ti, and Eu. These geochemical features suggest that the Zayu pluton samples are metaluminous to slightly peraluminous and are of highly fractionated I-type granite. The Zayu pluton samples have high εNd(t) values (-10.9--7.6) and low initial 87Sr/86Sr ratios (0.7120- 0.7179) relative to melts derived from mature continental crust in the Gangdese (e.g., Ningzhong Early Jurassic strongly peraluminous granite). The Zayu pluton samples are heterogeneous in zircon εHf(t) values (-12.8--2.9), yielding ancient zircon Hf crustal model ages of 1.4―2.0 Ga. The data obtained in this study together with the data in the recent literature suggest that the Early Cretaceous granitoids in eastern Gangdese represent the eastward extension of the Early Cretaceous magmatism in the middle Gangdese, and that the Lhasa micro-continent block with ancient basement may extend for ~2000 km from east to west. Zircon Hf isotopic data and bulk-rock zircon saturation temperature (789-821℃) indicate that mantle-derived materials likely played a role in the generation of the Zayu pluton. We propose that the Zayu pluton was most likely generated in a setting associated with southward sub- duction of the Bangong-Nujiang ocean floor, where mantle wedge-derived magmas may have providedthe heat and material for the anatexis of ancient crust of the Lhasa micro-continent, resulted in hybrid melts (i.e., mantle-derived basaltic magmas + crust-derived felsic magmas). Such hybrid melts with subsequent fractional crystallization are responsible for the highly evolved Zayu pluton (crust thick- ening is not a prerequisite). | ZHU DiCheng MO XuanXue WANG LiQuan ZHAO ZhiDan NIU Yaoling ZHOU ChangYong YANG YueHeng | 2009 | Science China Earth Sciences2009，52，9： | 107 |
| 2 | Role of mantle-derived magma in genesis of early Yanshanian granites in the Nanling Range, South China: in situ zircon Hf-O isotopic constraints显示文摘Although a number of petrographic observations and isotopic data suggest that magma mixing is common in genesis of many granite plutons, it is still controversial whether the mantle-derived magmas were involved in granites. We carried out in this study a systematic analysis of in situ zircon Hf-O isotopes for three early Yanshanian intrusions dated at ca. 160 Ma from the Nanling Range of Southeast China. The Qinghu monzonite has very homogeneous zircon Hf-O isotopic compositions, εHf(t) =11.6±0.3 and δ18O=5.4‰±0.3‰. In combination with whole-rock geochemical and Sr-Nd isotopic data, the parental magma of the Qinghu monzonite were likely derived from the partial melting of recently-metasomatized, phlogopite-bearing lithospheric mantle without appreciable crustal contamination. The Lisong and Fogang granites and the mafic microgranular enclaves (MME) within the Lisong granites have a wide range of zircon Hf-O isotopic compositions, with Hf and O isotopes being negatively correlated within each pluton. The Lisong MMEs were crystallized from a mantle-derived magma, similar to the parental magma of the Qinghu monzonite, with small amount of crustal assimilation. The Lisong and Fogang granites were formed by reworking of meta-sedimentary materials by mantle-derived magmas and mixing of the mantle-and sediment-derived melts to varying degrees. It is thus concluded that these two Yanshanian granites in the Nanling Range were formed associated with growth and differentiation of continental crust. | LI XianHua LI WuXian WANG XuanCe LI QiuLi LIU Yu TANG GuoQiang | 2009 | Science China Earth Sciences2009，52，9： | 101 |
| 3 | North Qinling Paleozoic granite associations and their variation in space and time: Implications for orogenic processes in the orogens of central China显示文摘Integrated zircon U-Pb dating and whole rock geochemical analyses have been carried out for two typical S-and I-type granitoids in the north Qinling. Zircon dating by SIMS of the Piaochi S-type grani- toids yields an emplacement age of 495±6 Ma. The granitoids show whole-rock εNd(t)=-8.2--8.8, zircon εHf(t)=-6―-39. The Huichizi I-type granitoids have emplacement ages of 421±27 Ma and 434±7 Ma es- tablished by LA-ICP-MS and SIMS methods, respectively. Their whole-rock εNd(t)=-0.9-0.9 and zircon εHf(t)=-11-8.4. Combined with statistical analyses of 28 zircon ages of granitoid plutons collected from the literature, Paleozoic magmatism in the north Qinling can be divided into three stages. The first-stage magmatism (~505-470 Ma) mainly occurred in the east part of the north Qinling and has features of an I-type arc, associated with which are S-type granitoids such as Piaochi pluton. The early granitoids (~505-490 Ma) have close spatio-temporal relations to ultra-high-pressure (UHP) rocks, and thus are interpreted as an oceanic subduction system along a continental margin. The second-stage magmatism (~450-422 Ma) occured through the whole north Qinling, and is characterized by I-type granitoids represented by the Huichizi pluton. The magma is interpreted as partial melting of lower crust mixed by mantle-derived magma in a collisional setting with the uplift of terranes. The third-stage magmatism (~415-400 Ma) is dominated by I-type granitoids and only took place in the middle part of the north Qinling, and is regarded as a late-stage collision. The spatial and temporal variations of the Qinling Paleozoic magmatism reveal protracted subduction/collision. The subduction was initiated from the east part of the north Qinling, earlier than that in the Qilian-northern Qaidam, Kunlun, and northern Dabie regions. This demonstrates variations in time of subduction, accretion and collision of separate blocks or terranes in the orogenic systems in central China. | WANG Tao WANG XiaoXia TIAN Wei ZHANG ChengLi LI WuPing LI Shan | 2009 | Science China Earth Sciences2009，52，9： | 79 |
| 4 | 中亚-蒙古造山带东段的锡林郭勒杂岩:早华力西期造山作用的产物而非古老陆块?——锆石SHRIMP U-Pb年代学证据显示文摘锡林郭勒杂岩是华北板块北缘古生代褶皱带内出露面积最大的变质岩系,以前多被当着前寒武纪的古老地块。本文通过对该杂岩中副片麻岩和正片麻岩的锆石SHRIMP U-Pb年代学研究发现,副片麻岩中的锆石多为岩浆锆石,其^(206)Pb/^(238)U加权平均年龄为406±7Ma,指示它们的原岩主要是由近同期(略早些)的岩浆岩风化后就近沉积的产物,该年龄应代表源区(岛弧型?)花岗岩的形成时间,同时也是副片麻岩原岩沉积的下限年龄。正片麻岩中岩浆锆石的^(206)Pb/^(238)U加权平均年龄为382±2Ma,代表花岗片麻岩原岩的侵位年龄。岩石中锆石的变质增生边的形成年龄为337±6Ma,代表锡林郭勒杂岩发生变质和变形的时间,该变质事件可能与贺根山缝合带内所发生的一次主要的碰撞造山作用有关。这些年龄资料充分说明,锡林郭勒杂岩并非古老地块,而是华力西早期岩浆作用、沉积作用和变质作用事件的产物.整个事件是在较短的时间范围内(~70Ma)完成的,推测该杂岩发育在碰撞造山带的弧前环境。中亚-蒙古造山带东南部(内蒙古的中、东部)碰撞前的构造格局可能不是典型的多岛洋体制,由于缺少古老的陆块,造山过程更多的表现为大洋的大陆化过程,即洋内俯冲形成岛弧,岛弧在被动大陆边缘拼贴聚合转化为新的大陆。 | 薛怀民 郭利军 侯增谦 周喜文 童英 潘晓菲 | 2009 | 岩石学报2009，25，8： | 63 |
| 5 | 秦-祁-昆造山带元古宙副变质岩层碎屑锆石年龄谱研究显示文摘根据秦-祁-昆造山带中北大河岩群、湟源岩群、化隆岩群、金水口岩群、陡岭岩群和秦岭岩群等副变质岩层碎屑锆石年龄谱资料,这些原定为古元古代的地层,至少包括测年样品在内的部分地层的时代应属中元古代或新元古代初期。研究资料还显示上述碎屑岩层具有大量中元古代早期的物源,而古元古代蚀源物质较匮乏。因此,上述副变质岩层显示出相近的碎屑锆石年龄谱特征。 | 陆松年 李怀坤 王惠初 陈志宏 郑健康 相振群 | 2009 | 岩石学报2009，25，9： | 77 |
| 6 | SHRIMP zircon U-Pb geochronology of early Mesozoic felsic igneous rocks from the southern Lancangjiang and its tectonic implications显示文摘The SHRIMP zircon U-Pb geochronology of three typical samples, including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang, western Yunnan Province. The analyses of zircons for the biotite monzonitic granites from the northern (02DX-137) and southern (20JH-10) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 206Pb/238U ages of 229.4 ± 3.0 Ma and 230.4 ± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02DX-95) from the Manghuai Formation give a weighted mean 206Pb/238U age of 231.0 ± 5.0 Ma. These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age. In combination with other data, it is inferred that both were generated at a narrow age span (~230 Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 206Pb/238U apparent age of 1977±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite (southern Lincang batholith), indicative of devel- opment of the early Proterozoic Yangtze basement in the region. These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys, western Yunnan Province. | PENG Touping1,2, WANG Yuejun1, FAN Weiming1, LIU Dunyi3, SHI Yuruo3 & MIAO Laicheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China 3. SHRIMP isotope Laboratory, Chinese Academy of Geological Sciences, Beijing 100037, China 4. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China | 2006 | Science China Earth Sciences2006，49，10： | 55 |
| 7 | The timing of tectonic transition from compression to extension in Dabieshan: Evidence from Mesozoic granites显示文摘With the methods of single grain zircon U-Pb and hornblende-biotite Ar-Ar dating, a U-Pb zircon age (135.4(2.7) Ma of Liujiawa high Sr/Y granite and 40Ar-39Ar plateau ages (139.0(1.0) Ma and (125.3(0.2) Ma of hornblende and biotite respectively of Fenliupu high Sr/Y granite in the Dabieshan high- and ultrahigh-pressure metamorphic belt are yielded. Following the emplacement of the high Sr/Y granites, extension-related mafic intrusions and late granitoids with negative Sr and Eu anomalies and isotopic ages of 105-130 Ma were emplaced. Geochemical comparison between the two types of granitoids shows that, from early to late, the alkalinities, the K2O contents and the Sr/Y ratios as well as FeO/(FeO+MgO) ratios of the rocks increase, while the abundance of Sr reduces, suggesting that as time goes on the depth of crustal melting decreases. Rheological stratification of the crust due to early Cretaceous partial melting of crustal rocks resulted in crustal extension and deep-buried rock exhumation. Therefore, the high Sr/Y granite that appeared at ~135 Ma is the product of the tectonic transition from early shortening to late overall extension. | MA Changqian YANG Kunguang MING Houli LIN Guangchun | 2004 | Science China Earth Sciences2004，47，5： | 51 |
| 8 | The oldest basement rock in the Yangtze Craton revealed by zircon U-Pb age and Hf isotope composition显示文摘Here we report an integrated study of zircon U-Pb age and Hf isotope composition for a gneiss sample from the Kongling terrain in the Yangtze Craton. CL imaging reveals that most zircons are magmatic, and a few of them have thin metamorphic rims. The magmatic zircons gave a weighted mean U-Pb age of 3218±13 Ma, indicating the gneiss is the oldest basement rock in the Yangtze Craton found to date. They have εHf(t) value of -2.33±0.51,and two-stage Hf model age of 3679±49 Ma,indicating that the gneiss was derived from partial melting of >3.6 Ga crustal rock. The metamorphic rims yielded an age of 2732±16 Ma, implying that the metamorphic event occurred in the Neoarchean era, which may be also a major tectono-thermal event in the Yangtze Craton. | JIAO WenFang WU YuanBao YANG SaiHong PENG Min WANG Jing | 2009 | Science China Earth Sciences2009，52，9： | 57 |
| 9 | 内蒙古贺兰山地区古元古代晚期的花岗岩浆事件及其地质意义:同位素年代学的证据显示文摘位于华北克拉通西缘的贺兰山杂岩主要由孔兹岩系和变形花岗岩(正片麻岩)所组成,前者主要由夕线石榴片麻岩、石榴二长片麻岩、变粒岩和少量的大理岩及麻粒岩所组成,后者主要包括黑云斜长片麻岩、石榴子石花岗岩、斑状花岗岩和片麻状变质闪长岩。本文报道了该区变形花岗岩的锆石SHRIMP U-Pb定年结果。黑云二长片麻岩和石榴子石花岗岩分别形成于2053±58Ma和2047±42Ma,斑状花岗岩和片麻状闪长岩分别在1955Ma和1920Ma侵位。大量的年代学资料表明,在华北克拉通北缘存在一条古元古代晚期的花岗杂岩带,该带中的花岗杂岩主要形成于三个阶段,第一阶段大于2.0Ga,第二阶段主要出现在2.0~1.87Ga期间,第三阶段的花岗杂岩在1.85~1.80Ga期间侵位。年代学研究还表明,古元古代晚期的花岗岩浆作用常常与变质事件紧密相关。 | 耿元生 周喜文 王新社 任留东 | 2009 | 岩石学报2009，25，8： | 47 |
| 10 | Tectonic evolution of the Western Kunlun orogenic belt in northern Qinghai-Tibet Plateau:Evidence from zircon SHRIMP and LA-ICP-MS U-Pb geochronology显示文摘The Western Kunlun Range in northern Qinghai-Tibet Plateau is composed of the North Kunlun Terrane,the South Kunlun Terrane and the Karakorum-Tianshuihai Terrane. Here we report zircon SHRIMP and LA-ICP-MS U-Pb ages of some metamorphic and igneous rocks and field observations in order to pro-vide a better understanding of their Precambrian and Palaeozoic-early Mesozoic tectonic evolution. Based on these data we draw the following conclusions: (1) The paragneisses in the North Kunlun Terrane are likely of late Mesoproterozoic age rather than Palaeoproterozoic age as previously thought,representing tectonothermal episodes at 1.0―0.9 Ga and ~0.8 Ga. (2) The North Kunlun Terrane was an orogenic belt accreted to the southern margin of Tarim during late Mesoproterozoic to early Neopro-terozoic,the two episodes of metamorphisms correspond to the assemblage and breakup of Rodinia respectively. (3) The Bulunkuole Group in western South Kunlun Terrane,which was considered to be the Palaeoproterozoic basement of the South Kunlun Terrane by previous studies,is now subdivided into the late Neoproterzoic to early Palaeozoic paragneisses (khondalite) and the early Mesozoic metamorphic volcano-sedimentary series; the paragneisses were thrust onto the metamorphic vol-cano-sedimentary series from south to north,with two main teconothermal episodes (i.e.,Caledonian,460―400 Ma,and Hercynian-Indosinian,340―200 Ma),and have been documented by zircon U-Pb ages. (4) In the eastern part of the South Kunlun Terrane,a gneissic granodiorite pluton,which intruded the khondalite,was crystallized at ca. 505 Ma and metamorphosed at ca. 240 Ma. In combination with geochronology data of the paragneiss,we suggest that the South Kunlun Terrane was a Caledonian accretionary orogenic belt and overprinted by late Paleozoic to early Mesozoic arc magmatism. | ZHANG ChuanLin LU SongNian YU HaiFeng YE HaiMin | 2007 | Science China Earth Sciences2007，50，6： | 45 |
| 11 | Zircon U-Pb geochronology,Hf isotopic composition and geological implications of the rhyodacite and rhyodacitic porphyry in the Xiangshan uranium ore field,Jiangxi Province,China显示文摘The Xiangshan uranium ore field is the largest volcanic rock hosted uranium deposit in China.The host rock is a volcanic intrusive complex,including rhyodacite,porphyroclastic lava and late stage sub-volcanic rocks.In this study,zircons from an early stage rhyodacite and a late stage rhyodacite porphyry were dated by SHRIMP and LA-ICP-MS U-Pb methods,and their Hf isotopic compositions were measured by LA-MC-ICP-MS.206Pb/238U ages of 135.1±1.7 and 134.8±1.1 Ma were obtained for the rhyodacite and rhyodacitic porphyry,respectively.These accurate ages indicate that the Xiangshan volcanic-intrusive complex formed in the Early Cretaceous rather than in the Late Jurassic,as concluded in some previous studies.By the Early Cretaceous,the tectonic setting of the area has evolved into a back-arc extensional setting,possibly related to subduction of the paleo-Pacific plate.The close ages of the(early) eruptive rhyodacite and the(late) hypabyssal rhyodacitic porphyry shows that the Xiangshan volcanism was intensive and concentrated in a short time.Zircons from the rhyodacite show negative εHf(t) values of-5.7 to-8.5,with Hf depleted mantle model ages between 1550 and 1720 Ma,whereas zircons from the rhyodacitic porphyry yield εHf(t) values of-6.9 to-10.1 and Hf model ages between 1621 and 1823 Ma.These zircon Hf model ages are similar to the whole rock Nd model ages(1486 to 1911 Ma).Combined with other geochemical characteristics,the Xiangshan rhyodacite and rhyodacitic porphyry may have been derived from partial melting of the Paleo-Mesoproterozoic metamorphic rocks from the Xiangshan basement,without any significant addition of mantle-derived magma.Contribution of basement of this age is also supported by finding a Paleoproterozoic xenocrystic zircon core in the rhyodacite sample. | YANG ShuiYuan JIANG ShaoYong JIANG YaoHui ZHAO KuiDong FAN HongHai | 2010 | Science China Earth Sciences2010，53，10： | 40 |
| 12 | Emplacement age of the post-orogenic A-type granites in Northwestern Lesser Xing'an Ranges, and its relationship to the eastward extension of Suo-lushan-Hegenshan-Zhalaite collisional suture zone显示文摘A great amount of alkali-feldspar and alkaline granites have been found around Nenjiang, Northwest Lesser Xing’an Ranges, but their forming ages have been a controversial subject due to the lack of reliable geological and isotopic geochronological evidence. The zircon U-Pb isotopic dating results conducted in this note indicate that these granites emplaced at 260-290 Ma, coeval with the late stage of Late Paleozoic. Studies of mineralogy, petrology andgeochemistry show that they are post-orogenic A-type granites, and consist of the northeastern extension of huge belt of Late Paleozoic A-type granite along North Xinjiang-Southeast Mongolia-Central Inner Mongolia. Therefore, we can determine that the Suolunshan-Hegenshan-Zhalaite collisional suture zone extends northeastward to Heihe with the collision age of Carboniferous. | Deyou Sun Fuyuan Wu Huimin Li Qiang Lin | 2001 | Chinese Science Bulletin2001，46，5： | 36 |
| 13 | SHRIMP U-Pb zircon age,geochemistry and Nd isotope of the Guandaoshan pluton in SW Sichuan:Petrogenesis and tectonic significance显示文摘SHRIMP U-Pb zircon age, geochemical and Nd isotopic data are reported for the Neoproterozoic Guandaoshan pluton in the Yanbian region, SW Sichuan. This pluton is of typical I-type granite and emplaced at (857±13) Ma. Geochemical and Nd isotopic characters suggest that the pluton was generated by partial melting of pre-existing, young (late Mesoproterozoic to early Neoproterozoic) low-K tholeiitic protolith within an intraplate anorogenic setting. The Guandaoshan pluton probably records the earliest magmatism induced by the proposed ca. 860-750 Ma mantle superplume beneath the supercontinent Rodinia. | 李献华 李正祥 周汉文 刘颖 梁细荣 李武显 | 2003 | Science China Earth Sciences2003，46，z1： | 33 |
| 14 | U-Pb dating of early Mesozoic granodioritic intrusions in southeastern Hunan Province, South China and its petrogenetic implications显示文摘The NE-trended Mesozoic granodioritic intrusions are spatially and temporally associated with the copper multi-metal mineralization in southeastern Hunan Province, South China. U-Pb dating result of single-grained zircons of four samples respectively from Shuikoushan, Baoshan, western Tongshanling and eastern Tongshanling intrusions reveals that their crystallization age spans a range from 172 Ma to 181 Ma, which also represents the oldest age of the regional copper multi-metal mineralization. Some of the zircon grains give an upper intercept age of about 1753 Ma and 207Pb/206Pb apparent age of (1752 ± 4) Ma, implying the involvement of the pre-Cambrian metamorphic (possible Middle Proterozoic) basement in their genesis. The presence of such a kind of zircon grains in these granodiorites indicates either that the parental magmas were assimilated by basement rocks during magma ascent or that lower/middle crustal rocks were one of the important components during the melting process. | 王岳军 李惠民 范蔚茗 梁新权 郭锋 | 2002 | Science China Earth Sciences2002，45，3： | 32 |
| 15 | Structure and deformation around the Gyirong basin, north Himalaya, and onset of the south Tibetan detachment system显示文摘Gyirong basin and its adjacent area are located at a special position in the Himalayan orogen, where the south Tibetan detachment system (STDS) and N-S trending rift converged. The north Himalayan orogen here can be divided into five petrologic-tectonic units successively from south to north: 1) the Greater Himalayan crystalline complex (GHC); 2) the STDS shear zone; 3) the Tethyan Himalayan sedimentary sequence (THS); 4) the late Cenozoic sedimentary basins, such as Gyirong and Oma basins; and 5) the Malashan gneiss dome. Structural studies show that this area experienced four stages of deformation: 1) the earlier south-directed thrusting, preserved both in the GHC and THS; 2) top-down-to-north slip along the STDS, normal faults related to this slip formed the early controlling structures of the Cenozoic basins,and the tilted pattern of the blocks between the basins indicated a north-directed slip; 3) east-west extension, the resultant N-S trending normal fault formed the eastern boundary of the basins; and 4) late gravitational collapse. Zircon SHRIMP U-Pb dating on the syn-deformational (leuco-) granite along the STDS indicates that the major activity of the STDS occurred at ca. 26 Ma, but its onset may have begun as early as ca. 36 Ma. | YANG XiongYing ZHANG JinJiang QI GuoWei WANG DeChao GUO Lei LI PengYuan LIU Jiang | 2009 | Science China Earth Sciences2009，52，8： | 33 |
| 16 | LA-ICP-MS zircon U-Pb dating from granitoids in southern basement of Songliao basin:Constraints on ages of the basin basement显示文摘Seven LA-ICP-MS zircon U-Pb datings from granitoids in the southern basement of the Songliao basin were done in order to constrain the ages of the basin basement. The cathodoluminescence (CL) images of the zircons from seven granitoids indicate that they are euhedral-subhedral ones with striped ab-sorption and obvious oscillatory zoning rims. The dating results show that a weighted mean 206Pb/238U age is 236±3 Ma for quartz diorite (sample No.T6-1) located in the western slope of the basin,that weighted mean 206Pb/238U ages are 319±1 Ma (2126 m) and 361±2 Ma (1994 m) for diorite (sample No.YC1-1) and granite (sample No.YC1-2) located in northern part of southeastern uplift of the basin,respectively,and that weighted mean 206Pb/238U ages are 161±5 Ma,165±2 Ma,165±1 Ma and 161±4 Ma for samples Q2-1,SN121,SN122,and SN72 granitoids located in southern part of southeastern uplift of the basin,respectively. The statistical results of ages suggest that the middle Jurassic granitoids con-stitute the main part of basement granitoids,and that the Hercynian and Indo-Sino magmatisms also occur in the basin basement. It is implied that the Songliao basin should be a rift one formed in the intracontinent or active continental margin settings in the late Mesozoic after the Middle Jurassic orogeny took place. | GAO FuHong XU WenLiang YANG DeBin PEI FuPing LIU XiaoMing HU ZhaoChu | 2007 | Science China Earth Sciences2007，50，7： | 31 |
| 17 | 德兴矿集区花岗闪长斑岩锆石U-Pb年龄、Hf同位素特征及其意义显示文摘德兴矿集区位于赣东北地区,是中国东部中生代钦杭成矿带中的大型铜金铅锌矿集区之一,集中了铜厂、富家坞和朱砂红斑岩铜钼(金)矿、银山银铜铅锌多金属矿和金山金矿等大型、超大型矿床。本文在系统的野外地质调查与样品采集的基础上,对铜厂、富家坞、朱砂红及银山花岗闪长斑岩进行了LA-MC-ICP-MS锆石U-Pb定年和原位Hf同位素分析。德兴矿集区花岗闪长斑岩的LA-MC-ICP-MS锆石U-Pb的4组年龄分别为:(171±1.2)Ma(铜厂)、(172±0.68)Ma(富家坞)、(173±1.3)Ma(朱砂红)、(176±1.5)Ma(银山),表明这些岩体均为中侏罗世的产物。样品Hf两阶段模式年龄平均值分别为861 Ma、876 Ma、904 Ma和941 Ma,正的εHf(t)平均值在4.34-5.54,Zr/Hf比值接近于上地幔的Zr/Hf比值。锆石Hf同位素组成显示,岩浆源区主要来源于亏损地幔组分,但在岩浆演化中遭受了古老地壳物质的混染,幔源物质在德兴矿集区花岗闪长斑岩的形成过程中发挥了重要作用。德兴矿集区4个矿床成岩成矿的最重要时期在170-175 Ma,该矿集区岩浆热液系统持续活动可能是该大型矿集区形成的重要原因。 | 水新芳 赵元艺 郭硕 吴德新 朱小云 王增科 | 2012 | 中国地质2012，39，6： | 33 |
| 18 | 黑龙江桦南地区黑龙江杂岩锆石U-Pb定年显示文摘黑龙江杂岩主要由绿片岩相变质岩和糜棱岩化构造片岩组成,长期以来与麻山杂岩一起被认为代表佳木斯地块的前寒武纪基底,但这种认识缺乏可信的同位素年代学及古生物资料的支持。对出露于黑龙江省东部桦南地区湖南营组绿片岩进行了锆石LA-ICP-MS U-Pb定年研究。结果显示锆石的Th/U比值为0.27~1.27,变化较大;获得两组^(206)Ph/^(238)U年龄数据:其加权平均年龄分别为:511±10Ma(n=13,MSWD=1.6)和274.7±3.6Ma(n=9,MSWD=0.91)。黑龙江杂岩中最老的年龄969~747Ma表现来自中元古和新元古代。这些年龄与黑龙江杂岩的年龄与来自俯冲碰撞变质事件的~511Ma的年龄结合起来,表明黑龙江杂岩中含有经历晚新元古——早古生代造山作用的碎屑锆石,亦或代表着在俯冲拼贴过程中混入的麻山杂岩块体。~275Ma年龄反映黑龙江杂岩经历的一次碰撞造山事件,可能与晚古生代古亚洲洋闭合相关。 | 李旭平 焦丽香 郑庆道 董晓 孔凡梅 宋召军 | 2009 | 岩石学报2009，25，8： | 30 |
| 19 | 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 |
| 20 | Late Triassic sedimentary records in the northern Tethyan Himalaya:Tectonic link with Greater India显示文摘The Upper Triassic flysch sediments(Nieru Formation and Langjiexue Group)exposed in the Eastern Tethyan Himalayan Sequence are crucial for unraveling the controversial paleogeography and paleotectonics of the Himalayan orogen.This work reports new detrital zircon U-Pb ages and whole-rock geochemical data for clastic rocks from flysch strata in the Shannan area.The mineral modal composition data suggest that these units were mainly sourced from recycled orogen provenances.The chemical compositions of the sandstones in the strata are similar to the chemical composition of upper continental crust.These rocks have relatively low Chemical Index of Alteration values(with an average of 62)and Index of Compositional Variability values(0.69),indicating that they experienced weak weathering and were mainly derived from a mature source.The geochemical compositions of the Upper Triassic strata are similar to those of graywackes from continental island arcs and are indicative of an acidicintermediate igneous source.Furthermore,hornblende and feldspar experienced decomposition in the provenance,and the sediment became enriched in zircon and monazite during sediment transport.The detrital zircons in the strata feature two main age peaks at 225-275 Ma and 500-600 Ma,nearly continuous Paleoproterozoic to Neoproterozoic ages,and a broad inconspicuous cluster in the Tonian-Stenian(800-1200 Ma).The detrital zircons from the Upper Triassic sandstones in the study area lack peaks at 300-325 Ma(characteristic of the Lhasa block)and 1150-1200 Ma(characteristic of the Lhasa and West Australia blocks).Therefore,neither the Lhasa block nor the West Australia blocks likely acted as the main provenance of the Upper Triassic strata.Newly discovered Permian-Triassic basalt and mafic dikes in the Himalayas could have provided the 225-275 Ma detrital zircons.Therefore,Indian and Himalayan units were the main provenances of the flysch strata.The Tethyan Himalaya was part of the northern passive margin and was not an exotic terrane separated from India during the Permian to Early Cretaceous.This evidence suggests that the Neo-Tethyan ocean opened prior to the Late Triassic and that the Upper Triassic deposits were derived from continental crustal fragments adjacent to the northern passive continental margin of Greater India. | Huawen Cao Yong Huang Guangming Li Linkui Zhang Jianyang Wu Lei Dong Zuowen Dai Liu Lu | 2018 | Geoscience Frontiers2018，9，1： | 27 |
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