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| 1 | Discovery of the Dagele Eclogite in East Kunlun,Western China and Its Zircon SHRIMP U-Pb Ages:New Constrains on the Central Kunlun Suture Zone显示文摘Objective Eclogites are important indicators of ancient plate boundaries or paleosuture zones.Despite their great geological significance,very few investigations have been carried out in the Kunlun region.The Central East Kunlun fault zone was believed to be an Early Paleozoic suture zone,but there has been no reliable evidence for this,though studies on ophiolite,granite,and basic granulite indicate that the Early Paleozoic orogeny occurred in the East Kunlun.This work focused on the Dagele eclogites | DU Wei JIANG Changyi Tang Zhongli XIA Mingzhe XIA Zhaode LING Jinlan ZHOU Wei WANG Bangyao | 2017 | Acta Geologica Sinica(English Edition)2017，91，3： | 5 |
| 2 | Geochronology,Petrology and Geochemistry of Xingdi No.3 Mafic-Ultramafic Intrusions in the Northeastern Tarim Craton,NW China显示文摘The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km^2, and the zircon U-Pb age of the intrusion is 752±4 Ma. The intrusion consists of gabbros, pyroxenites and peridotites, and exhibits a crystallization sequence of the main rock-forming minerals as olivine, orthopyroxene, clinopyroxene and plagioclase. Mineralization occurred at or near the boundaries of the intrusion between pyroxenites and peridotites, and appears as a layered or lenticular shape about 500 m long and 4–15 m wide. The primary sulfides have a relatively simple mineralogy dominated by pyrrhotite-pentlandite-chalcopyrite assemblages, which occur as droplet, star-like and graphic texture and locally sideronitic structures. Geochronological and geochemistry investigations suggest that the Xingdi mafic-ultramafic intrusions and coeval volcanic rock in the Kuluktag area of the Tarim craton formed in an intracontinental breakup environment. Based on the composition of the dominant rockforming minerals and covariant relationships of other oxides versus Mg O, the parental magma of the Xingdi No.3 intrusion belongs to high-Mg tholeiitic basaltic magmas with Mg O of 10.78 wt%. The Xingdi No.3 intrusive rocks are characterized by light REE enrichment relative to heavy REE, negative Nb-Ta anomalies, low ^(143)Nd/^(144)Nd ratios(from 0.511183 to 0.511793) and high initial ^(87)Sr/^(86)Sr ratios(from 0.7051 to 0.7113). The magma was derived from the enriched-lithospheric mantle and was contaminated during emplacement. According to rock assemblages, mineralization, olivine characteristics, geochemical characteristics and mass balance, there are better copper-nickel ore prospects in the Xingdi No.3 intrusion than in the other three intrusions in the area. | XIA Zhaode XIA Mingzhe JIANG Changyi | 2017 | Acta Geologica Sinica(English Edition)2017，91，2： | 2 |
| 3 | Origin of Chromitites in the Songshugou Peridotite Massif,Qinling Orogen (Central China): Mineralogical and Geochemical Evidence显示文摘The Songshugou peridotite massif is located in the north of Shangdan suture zone, North Qinling orogenic belt of Central China. The massif is mainly composed of fine-grained mylonitic dunites, coarse-grained dunites, fine- and coarse-grained harzburgites, and minor clinopyroxenites. The coarsegrained dunites as well as parts of the harzburgites host small-scale chromitites? Chromite grains from various textural types of chromitites and dunites pervasively contain primary and secondary silicate inelusions. Primary inclusions are dominated by monophase olivine, with minor clinopyroxene and a few multiphase mineral assemblages consisting of olivine and clinopyroxene. Secondary inclusions, mainly Cr-chlorite and tremolite, show irregular crystal shapes. Besides, Cr2O3 contents (0.08 wt.%-0.71 wt.%) of primary olivine inclusions are remarkably higher than those of interstitial olivine (<0.1 wt.%). Chr0- mites in the Songshugou peridotite massif are high-Cr type, with Cr^# and Mg^# values ranging of 67.5-87.6, and 23.4-41.2, respectively. The Cr-chlorite, formed by reactions between olivine and chromite in the presence of fluid under middle temperature, indicates the Songshugou peridotite massif has undergone alteration/metamorphism process during emplacement. Chromite grains are modified by these processes, resulting in the various degrees of enrichment of Fe2O3, Cr2O3, Zn, Co and Mn, depletion of MgO, A12O3,Ga, Ti and Ni. Due to low silicate/chromite ratios in the massive ores, chromites from them are slightly influenced by alteration/metamorphism and thus preserve the pristine magmatic compositions. The parental magma calculated based on them has 11.17 wt.%-13.57 wt.% A12O3 and 0.15 wt.%-0.27 wt.% TiO2, which is similar to the parental melts of high-Cr chromitites from elsewhere and comparable with those of boninites. Combined with informations from previous studies, major and trace elements geochemistry of chromite, as well as the nature of the parental magma, it can be revealed that the Songshugou chromitities formed in a supra-subduction zone environment. | Huichao Rui Jiangang Jiao Mingzhe Xia Jingsui Yang Zhaode Xia | 2019 | Journal of Earth Science2019，30，3： | 1 |
| 4 | Geochemical characteristics and provenance analysis of Lower Jurassic Badaowan Formation in Changji area of Xinjiang,China显示文摘Based on the field survey of Lower Jurassic Badaowan Formation(Fm.)in Changji area of Xinjiang,China,the authors studied the sedimentary environment and provenance characteristics using the analyses of stratigraphic profiles,sedimentary structures,petrography,zircon U-Pb chronology and geochemistry.The results show that Badaowan Fm.deposited in fluvial to swamp shallow-deeplacustrine sedimentary facies deposition.Contents of Sr and ratios of Sr/Cu,Sr/Ba,Th/U,SiO_(2)/Al_(2)O_(3),V/(V+Ni),V/Cr,and Cu/Zn together indicate that Badaowan Fm.was deposited in an oxygen-poor transitional freshwater environment,under humid climatic conditions.Geochemical characteristics and Q–F–L,Qm–E–Lt,Th–Co–Zr/10,La–Th–Sc,and Th–Sc–Zr/10 discrimination diagrams indicate that the tectonic setting of the source area was a continental island arc environment.Lithological composition,Th/U ratios,and Co/Th–La/Sc,La/Th–Hf,and La/Yb–REE discrimination diagrams show that the source rocks of Badaowan Fm.were upper-crust felsic volcanic rocks.U-Pb dating of detrital zircons yields ages of 1542.3±15.0 to 232.9±3.3 Ma and mostly in the ranges of 470–410 and 370–280 Ma.A comparison of these ages with the age data from different blocks of crystalline rock in Tianshan Mountains area reveals that the sedimentary rocks in the Badaowan Fm.were sourced predominantly from the central and subordinately from the southern Tianshan Mountains during Early Jurassic. | LIU Zhanjin XIA Zhaode LIU Yunhua DU Jinhua WANG Shuo ZHANG Yunfei GAO Jinghui | 2023 | Global Geology2023，26，2： | 0 |
| 5 | Magma source and tectonic setting of the Dunde granite in the Western Tianshan:constraints from geochronology,geochemistry,and Sr–Nd–Hf isotopes显示文摘The Dunde iron-zinc polymetallic deposit is one of large iron deposits occurred in the Awulale Metallogenetic Belt,Western Tianshan(NW-China).This study reports new geochronology and geochemistry for granite in the Dunde mining area in order to constrain the tectonicmagmatic activities and metallogenesis of this region.Granites in the southwest of Dunde mining area are mainly syenogranites intruded into volcanics of the Dahalajunshan Formation in the Early Carboniferous,and they are far from the area where ore bodies and mineralized altered rocks are widely developed.LA-ICP-MS U–Pb zircon dating indicates that Dunde syenogranite was at 306.8±1.0 Ma,which could constrain the upper limit of metallogenic age for this deposit.The Dunde granites are high SiO_(2)(73.41–80.07 wt%),high differentiation index(D.I.=89.7–95.0),weakly peraluminous to metaluminous(A/CNK=0.94–1.08),and they are enriched in LILE and LREE and depleted in Eu,Ba,Sr and P_(2)O_(5),indicating that they belong to highly fractionated Ⅰ-type granite.Based on εHf values(+9.2 to+10.5)for zircon and high εNd(-t)values(+4.7 to+5.8)for whole-rock,and the two-stage model ages for 601–735 Ma,suggest that the magma source could be the juvenile lower crust.Combined with regional geological setting,the 306.8 Ma Dunde granites are formed in post-collision extensional tectonic setting. | Zhaode Xia Haibo Ding Yanjiao Ru | 2023 | Acta Geochimica2023，42，5： | 0 |
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