The Zhunuo ore district, at the western end of the Gangdese porphyry Cu belt, hosts significant Cu mineralization and newly recognized W mineralization dominated by scheelite. However, the genetic relationship between scheelite and porphyry mineralization, and the evolution of ore-forming fluids remain poorly constrained. To address this, scheelite samples from multiple locations were analyzed for major elements (EMPA), in situ trace elements (LA-ICP-MS), and internal textures (cathodoluminescence, CL). These data, combined with machine learning methods, were used to determine scheelite genetic types and reconstruct fluid evolution. REE patterns and CL textures reveal three scheelite generations in Yalongri (early Sch I c, middle Sch I b, late Sch I a), two in Zhigunong (early Sch II a, late Sch II b), and one in Xiongbaxi (Sch III). Low Na (0-329 ppm) and Nb (3.9-39 ppm) relative to high Sigma REE + Y-Eu (16-3857 ppm), indicate that the dominant substitution mechanism is 3Ca(2+) = 2REE(3+) + square Ca (square Ca = Ca vacancy). delta Eu values > 1 in Sch I a, Sch I b, Sch II a, and Sch II b indicate reducing fluids, whereas delta Eu < in Sch I c and Sch III reflects oxidizing conditions. Variations in REE, Mo, and Sr contents suggest that ore-forming fluids in Yalongri evolved from oxidizing to reducing conditions, with late-stage scheelite undergoing dissolution-reprecipitation. Zhigunong records two reducing stages: an early REE-rich-Mo-poor stage and a later REE-poor-Mo-rich stage. Xiongbaxi records a single oxidizing, REE-rich, Mo-rich stage. Scheelite exhibits low-to-moderate Sr/Mo ratios (0.02-6.10), consistent with a magmatic-hydrothermal origin, and relatively uniform Y/Ho ratios (12-59) indicating stable crystallization conditions. A Random Forest model classifies scheelite into orogenic, porphyry, skarn, and greisen types. Overall, the results indicate that ore-forming fluids evolved from oxidizing to reducing conditions, favoring metal transport and enrichment. Integrated geochemical and machine learning evidence suggest, strong potential for porphyry-type Cu-W(-Mo) mineralization in Yalongri and Zhigunong, and skarn-type W-Mo mineralization in Xiongbaxi, providing important guidance for future exploration in the western Gangdese metallogenic belt.

城市信号交叉口是城市交通网络的重要节点、也是交通事件的频发区域之一.为提高网联车队在交叉口处的通行效率,降低车辆平均停车延误,提出一种车联网环境下基于可变相位的车队交叉口信号控制模型.根据车辆初始速度与车辆加入随机性,引导车辆以固定间距车队形式通行;通过信号控制区域栅格化处理,收缩车辆停车等待时间,减少车辆平均停车延误,并对周期内各相位放行时间进行优化,调整绿灯相位时长使车队完整通过交叉口.利用SUMO仿真软件对实际交叉口采集真实数据进行验证,将提出方法与现有信号控制方法进行比对,分析不同放行方式下的延误.结果显示,其效果在平均延误方面减少 43.10%和 10.86%,平均排队长度减少 38.46%和13.80%.构建的方法有较好的可行性与适用性,可以为城市网联信号控制优化提供借鉴与参考.

目前已有研究对印度-欧亚板块碰撞时限的认识存在诸多分歧.本文对西藏林周县中部出露的托龙岩体开展了锆石U-Pb年代学、全岩地球化学和锆石Hf同位素分析,以期进一步约束印度-欧亚板块的碰撞时间.托龙岩体内出露的石英二长斑岩呈岩株状侵入到帕那组中,锆石U-Pb定年结果显示该石英二长斑岩形成于始新世(50.5±0.6 Ma),锆石εHf(t)值为-0.6～-0.5.石英二长斑岩具有较低的A/CNK值、较高的K2O含量和K2O/Na2O值,属于准铝质和钾玄岩系列.岩石普遍亏损高场强元素Nb、Ta、Ti和P,富集大离子亲石元素Th、U和Pb,轻、重稀土元素分异明显,(La/Yb)N=15.3～16.3,Eu负异常较弱,δEu=0.56～0.69.托龙岩体较低的A/CNK值、P2O5与SiO2的负相关性以及Y含量与Rb含量之间的正相关性,表明托龙石英二长斑岩为Ⅰ型花岗岩.综合岩体的地球化学特征、同位素特征和前人研究成果,认为托龙石英二长斑岩可能是相对古老的变质中基性岩部分熔融的产物,形成于印度-欧亚板块碰撞引起的俯冲板片断离环境,指示了印度-亚洲大陆的碰撞应发生于50 Ma之前.

早白垩世OIB(洋岛玄武岩)型基性岩在特提斯喜马拉雅带广泛分布,但对其形成构造背景的认识仍存在争议.本文基于浪卡子地区东北部卡龙辉长岩的锆石LA-ICP-MS U-Pb年代学、微量元素与同位素地球化学的新证据显示,该基性岩体年龄为136.6±1.4 Ma,形成于早白垩世的早期.地球化学显示出高的TiO2和Nb含量,低的MgO含量,弱的Nb、Ta正异常,以及轻稀土相对富集而重稀土亏损的特点.这些特征与OIB型基性岩的地球化学特征完全一致.而且卡龙辉长岩具有较低的Sr同位素初始值ISr以及较高的εNd(t)值,也与特提斯喜马拉雅带上典型的OIB型基性岩的同位素组成一致.综合分析后认为,卡龙辉长岩应与措美大火成岩省中的OIB型基性岩成因一致,均代表了Kerguelen地幔柱作用下的产物.

川藏铁路雅安至林芝段,已全面进入工程建设实施阶段.为稳步推进这一重大工程顺利建设,国家发改委强调,将会同有关部门加强统筹协调,落实落细各项工作.针对川藏铁路沿线特殊复杂的地理、人文环境,施工人员按需配置和高质量人才培养保障措施的研究具有重要意义.本章内容立足于川藏铁路用人需求,分别从技术保障、人员保障、组织实施保障及政策与制度保障四个方面,对川藏铁路人才培养模式及实施方案进行探索,并给出相关建议.

汤白矿区位于西藏冈底斯斑岩铜矿带西段南缘,南侧紧邻日喀则弧前盆地.矿区由地表探矿工程控制3条赋存于早侏罗世角闪石英闪长斑岩中的主矿体(1号、2号和3号),在野外地质调查的基础上,对角闪石英闪长斑岩进行LA-ICP-MS锆石U-Pb定年和岩石地球化学测试.研究结果表明:①含矿斑岩的成岩年龄为183.3±1.2Ma,形成于早侏罗世;②含矿斑岩地球化学特征与大洋岛弧背景下的安山质岩石的地球化学性质一致,表明汤白矿区含矿斑岩形成于大洋岛弧环境;③西藏冈底斯斑岩铜矿带具有寻找俯冲期斑岩型矿床的巨大潜力,今后应加强该带俯冲期斑岩型矿床的勘查评价工作,特别是早—中侏罗世斑岩的成矿潜力评价.

兹格塘错超基性岩位于班公湖—怒江结合带中段,是东巧蛇绿岩套的一部分,是班公湖—怒江结合带中段最著名的产铬铁矿床的蛇绿岩残片之一.在上世纪90年代,该地区东巧铬铁矿床已开采完毕,为了进一步增加铬铁矿床储量,实现找矿突破,在该地区作进一步的找矿勘查工作.通过对兹格塘错超基性岩体岩相带划分、地球化学分析,认为该区有良好的铬铁矿床成矿潜力,在兹格塘错的扎格多地区的宽阔的断陷盆地内出露的蛇纹石化辉橄岩值得进一步勘察.

The Bairong-Bairongxi porphyry Cu-Mo district is located in the middle part of Gangdese porphyry copper belt in southern Tibet, China. It has sparse mineralization, complicated magmatic intrusions, no central alteration zonation and no typical ore-related porphyry. Therefore, 'where is the magmatic-hydrothermal-mineralized center of Bairong-Bairongxi' is becoming the key of further studies. To address this issue, based on detailed geological survey and drills records, combined with the observation of microscope, zircon U-Pb dating and molybdenite Re-Os dating analysis, we concluded the following points: (1) The Bairong-Bairongxi is not two separated ore districts but belongs to an united porphyry mineralization system; (2) The magmatic sequences include biotite monzonitic granite, monzonitic granite porphyry (13.9 +/- 0.2Ma), granodiorite porphyry (13.8 +/- 0.2Ma), dacite porphyry (12.6 +/- 0.4Ma) and lamprophyre (11.1 +/- 0.2Ma); (3) The Re-Os age of molybdenite is from 13.35 +/- 0.19Ma to 13.82 +/- 0.20Ma; (4) The magmatic-hydrothermal-mineralized center is in its central regions; (5) Most of drillings are located in the argillic alteration zone but deep drillings revealed medium-high temperature veinlets, indicating the alteration has its origin in the deep. As mentioned above, Bairong-Bairongxi is in the top of a Cu-Mo porphyry system with clear magmatic-hydrothermal-mineralized center, and has great potential in Cu-Mo mineralization in the deep. This work gives an overview picture of Bairong-Bairongxi porphyry Cu-Mo district and is helpful for further exploration and studies.

AbstractJurassic sandstones in the Xiongcun porphyry copper–gold district, southern Lhasa subterrane, Tibet, China were analysed for petrography, major oxides and trace elements, as well as detrital zircon U–Pb and Hf isotopes, to infer their depositional age, provenance, intensity of source-rock palaeo-weathering and depositional tectonic setting. This new information provides important evidence to constrain the tectonic evolution of the southern Lhasa subterrane during the Late Triassic – Jurassic period. The sandstones are exposed in the lower and upper sections of the Xiongcun Formation. Their average modal abundance (Q21F11L68) classifies them as lithic arenite, which is also supported by geochemical studies. The high chemical index of alteration values (77.19–85.36, mean 79.96) and chemical index of weathering values (86.19–95.59, mean 89.98) of the sandstones imply moderate to intensive weathering of the source rock. Discrimination diagrams based on modal abundance, geochemistry and certain elemental ratios indicate that felsic and intermediate igneous rocks constitute the source rocks, probably with a magmatic arc provenance. The detrital zircon ages (161–243 Ma) and εHf(t) values (+10.5 to +16.2) further constrain the sandstone provenance as subduction-related Triassic–Jurassic felsic and intermediate igneous rocks from the southern Lhasa subterrane. A tectonic discrimination method based on geochemical data of the sandstones, as well as detrital zircon ages from sandstones, reveals that the sandstones were most likely deposited in an oceanic island-arc setting. These results support the hypothesis that the tectonic background of the southern Lhasa subterrane was an oceanic island-arc setting, rather than a continental island-arc setting, during the Late Triassic – Jurassic period.

为厘定拉孜县彭措林石英闪长斑岩的形成时代,探讨其成因和形成的构造背景,对其进行了锆石LA-ICP-MS U-Pb定年和锆石原位Hf同位素、全岩地球化学分析。结果表明,石英闪长斑岩的结晶年龄为（171.8±2）Ma,代表中侏罗世的岩浆活动;锆石的εHf（t）值为12.88～15.26,显示出新生地壳的特点。在全岩地球化学组成上,石英闪长斑岩具有高SiO2（64.99%～67.51%）、K2O（1.84%～3.22%）,低MgO（0.67%～0.93%）特点,微量元素地球化学特征显示岩石相对富集大离子亲石元素（如Rb、Sr和K）和轻稀土元素,亏损高场强元素（如Nb、Ta和Ti）和重稀土元素。结合前人资料,认为岩石产于与新特提斯洋向北俯冲相关的火山弧环境。此外,岩石具有相对高的Sr、Ba含量、无Eu负异常,表明源区无斜长石的明显残留;且较低的Mg#值,低的Cr、Ni含量和较低的εHf（t）值,均表明其主要形成于下地壳的部分熔融。

Objective Lhasa terrane has recorded the geologic history concerning the formation and evolution of Paleo-Tethys and the intra-continental convergence in Qinghai–Tibet Plateau（Yin and Harrison,2000）.Previous investigations have focused on the initial timing of the India-Asia collision and the Cretaceous–Cenozoic magmatism and sedimentation（Wang Tianyang et al.,2017）,however,

The Xiongcun mining area is located in the Gangdese porphyry copper belt in the southern margin of Lhasa terrane.To discuss the source of ore-forming materials of newly explored No.Ⅲ ore body in this mining area, this paper reports its sulfur and lead isotopesof pyrite and chalcopyrite.Test results show that the δ34 S values of ore sulfides vary from -1.3‰ to 1.4‰ with an average value of -0.85‰, and δ34 S∑S value is -0.04‰, indicating that sulfur is mainly from the mantle.The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios for metal sulfides vary in ranges of 18.204-18.468, 15.549-15.593 and 38.213-38.441, with the average value is 18.359, 15.567 and 38.351, respectively.Theμvalues of lead isotope range from 9.37 to 9.45 (mean=9.40) .In the discrimination diagrams of the tectonic setting, the Pb isotope is mostly plotted in orogenic belt field, suggesting the Pb materials are mainly from the mantle, with little subduction sediments mixed.

Lamprophyres are widespread in the Xiongcun porphyry copper-gold district in the southern margin of the Lhasa terrane. They represent the latest magmatism and cut all other rock types as well as orebodies in the Xiongcun district. Herein, we report the zircon LA-ICP-MS U-Pb age, whole-rock major and trace elements and Sr-Nd-Pb isotopic compositions of lamprophyre from the Xiongcun district. LA-ICP-MS zircon U-Pb dating yields crystallization ages in Eocene at 47.03 +/- 0.61Ma for the Xiongcun lamprophyre. The major element contents of the Xiongcun lamprophyres exhibit high Mg# along with calc-alkaline and ultrapotassic characteristics. The lamprophyres are enriched in LILEs (e.g., K, Rb, and Ba) and LREEs but depleted in HFSEs (e.g., Nb, Ta, and Ti). The Xiongcun lamprophyres are characterized by high (Sr-87/Sr-86)(i) ratios ranging from 0.71846 to 0.71858, low epsilon Nd(t) values ranging from -14.44 to -15.09, and enriched in radioactive Pb with (Pb-206/Pb-204)(i), (Pb-207/Pb-204)(i) and (Pb-208/Pb-204)(i) ranging from 18.53-18.97, 15.62-15.75, and 38.75-39.53, respectively. On the basis of the geochemistry of the Xiongcun lamprophyres, we propose that they were derived from the partial melting of an enriched lithospheric mantle source that was metasomatized by fluids released from the subducted Neo-Tethyan oceanic slab and Indian continental crust. This enriched lithospheric mantle source is characterized by phlogopite-and garnet-bearing lherzolite. The break-off of the subducted Neo-Tethyan oceanic slab from the Indian continental lithosphere at 45 similar to 50 Ma resulted in asthenospheric upwelling through the slab window. Subsequently, the enriched lithospheric mantle was heated by the underlying hot asthenosphere and partially melted, generating the magma that ascended to form the Xiongcun lamprohyres in an extensional tectonic setting. The parent magmas were fractionated during their ascent, whereas the effect of crustal assimilation on the magma was limited.

The Xiongcun copper-gold ore district is situated in the Gangdise porphyry copper belt located on the south margin of the Lhasa terrane. It has the characteristics of the great prospecting potential (more than 2.5 million tons of copper resources, 250 tons of gold and 1100 tons of silver), and special geological background. Through the comprehensive analysis of the exploration and the existing research results in the Xiongcun ore district, this paper makes a detailed summary from four aspects of geological characteristics, geophysical characteristics, geochemical characteristics and remote sensing characteristics, and analyzes the characteristics and internal relations of various metallogenic conditions. The authors have established a comprehensive information prospecting model with the aim of searching for ore deposits and expanding the quantity of resources. Prospecting model shows the Early and Middle Jurassic porphyry and the surrounding tuff are the main ore-bearing rock. The K-silicate alteration, sodic-calcic alteration, phyllic alteration and prolitic alteration are the main alteration type. Cu-Au-Ag element geochemical anomaly is an important indicator of geochemistry. The orebodies are controlled by NW and EW trending faults. Ground magnetic survey of high or low magnetic anomalies and remote sense alteration anomalies (K-silicate alteration, sericite alteration and ferric contamination) as well as linear and ringlike structures are the main indicators of geophysical and remote sensing, respectively. The authors delineated three Class A prospecting targets (A-1, A-2 and A-3), four Class B prospecting targets (B-1, B-2, B-3 and B-4) and two Class C prospecting targets (C-1 and C-2) in the Xiongcun area based on the comprehensive information prospecting model. Meanwhile the authors evaluated each prospecting target area.

Xiongcun copper-gold deposit is located in the middle of the southern margin ofthe Gangdise orogenic belt.Its southern margin is near to the Yarlung Zangbo suture zone (IYS) and Xigaze forearc basin, and the north is Xietongmen Eocene biotite granodiorite batholith.Based on the comprehensive microscopical identification and the analytical contents of major elements and trace elements (including REE) from the Xiongcun sandstones, the tectonic settings and provenance were studied.The result of study indicates that the content of SiO2 varies from 53.27％ to 66.13％ (average 58.27％) and is similar to that (66.1％) of Paleozoic greywackes.The high content of Al2O3 varies from 14.53％ to 24.04％ (average 20.12％), this may suggest that there are some feldspar in sandstones and with strong clayization.Combined with the microscopic characteristics, the Xiongcun sandstone may belong to feldspathic lithic sandstone.The special major element assemblages Fe2O3 + MgO (7.3 ％ ～ 17.6 ％), TiO2 (0.68 ％ ～ 1.25 ％) and Al2O3/SiO2(0.22％～0.45％) of the Xiongcun sandstones are similar to those of Oceanic Island Arc.It can be seen from the spider diagram that the Xiongcun sandstones are depleted in HFSE elements such as Ta, Nb, P,Ti and HREE, and enriched with LILE elements such as K, Rb, U and REE.The chondrite standard curve of REEs has rightward trend which reveals an enrichment of LREEs and an indifference of HREEs.The contents of standard trace elementsTh (2.5×10-6), Zr (114×10-6), Hf (3.6×10-6), Ce (27.95×10-6), Ti (0.54×10-6) and the ratios of trace elements Th/U (2.9), Zr/Th (46), La/Sc (0.72), Th/Sc(0.11) show that the genesis of the Xiongcun sandstones is Oceanic Island Arc.The discriminatory diagrams of La-Th-Sc, Th-Sc-Zr/10 and Th-Co Zr/10 were the same result.There are weak negative Ce anomalies and positive Eu anomalies in the PAAS-normalized rare element plots, which show the same conclusion with these from major elements and trace elements, indicating that the sandstones are influenced by both seawater and the fluids from deep.Diagrams of Co/Th-La/Sc and La/Th-Hf show that the provenance of Xiongcun sandstones is mixed with intermediate acidic felsic volcanic rocks and andesitic volcanic rocks.Combined with the detrital zircon ages of the sandstones (studied by other researcher), it is considered that the detrital zircon ages are not early in Late Triassic, and the provenance is of island arc volcanics features.

Lhasa terrane is a key area in studying the formation and evolution of Paleo-Tethys and the intra-continental convergence in the Tibetan Plateau. Lots of precious studies have been devoted to the Cenozoic geological evolution process in Lhasa terrane; nevertheless, the study of the Paleozoic evolution remains very insufficient. Focusing on the newly found Early Carboniferous gabbro in Xiongcun area on the southern margin of Lhasa terrane, the authors conducted zircon LA-ICP-MS U-Pb dating for gabbro in Xiongcun area, and investigated its tectonic significance. Zircon LA-ICP-MS U-Pb age of Xiongcun gabbro is (341.55±0.89) Ma, indicating that it was formed in Early Carboniferous epoch. Combining with the regional geological evolution process, the authors consider that Early Carboniferous Xiongcun gabbro might be the remnant of Paleo-Tethys Oceanic crust, and the newly presented dating data would provide significant constraint for studying the evolution process of Lhasa terrane and Paleo-Tethys Ocean.

雄村矿区位于西藏冈底斯斑岩铜矿带西段,目前在该矿区发现了Ⅰ、Ⅱ、Ⅲ号斑岩型铜金矿体.文章通过Ⅱ号矿体硫、铅同位素研究,获得Ⅱ号矿体金属硫化物的δ34S值为-1.6‰～-0.6‰,平均值-1.30‰,总硫同位素值(δ34S∑S)为0.99‰,与含矿斑岩的硫同位素组成(-2.1‰～+1‰,平均0.06‰)一致,均落入幔源硫范围,表明硫主要来自岩浆.含矿斑岩和金属硫化物的铅同位素组成206 Pb/204 Pb、207Pb/204Pb、208 Pb/204Pb分别为18.460～18.560、15.586～15.622、38.603～ 38.727和17.972～ 18.425、15.528～15.593、38.024～38.489,两者的铅同位素组成基本一致,变化范围小,表明两者具有相同的来源.所有样品的铅同位素μ值为9.34～9.49,显示幔源特征,综合源区判别图解认为铅主要来源于幔源,有少量俯冲沉积物加入,矿床形成于与洋壳俯冲消减作用有关的岛弧构造环境.

西藏列廷冈铁多金属矿床位于冈底斯-念青唐古拉岩浆弧北缘,是冈底斯北缘Pb-Zn-Ag-Cu-Fe多金属成矿带上典型的铁多金属矿床,与成矿关系最为密切的岩体为花岗闪长岩和花岗斑岩.采用锆石LA-I CP-MS对花岗闪长岩和花岗斑岩进行了定年,结果显示花岗闪长岩的成岩年龄为58.69±0.68 Ma,花岗斑岩成岩年龄为60.69±0.98 Ma.与加拉普铁多金属矿、沙让钼矿、亚贵拉铅锌银矿等冈底斯-念青唐古拉岩浆弧上其它矿床的对比分析表明,这一系列矿床受印度-欧亚大陆碰撞过程中地幔的岩浆底侵作用影响,形成于印度-亚洲大陆碰撞早期.列廷冈锆石的Lu-Hf测试结果显示岩体的εHf(t)值为3.01～3.0,Hf二阶段模式年龄742～1 322 Ma,表明岩浆具有壳幔混源的特点.结合列廷冈的目前勘探情况,认为在区域的铁多金属矿中,深部的Cu、Pb、Zn矿产将是今后勘查方向.

The Duobuza deposit is the first porphyry-type copper deposit discovered with giant prospect in the Bangongco metallogenic belt. Geochemical data indicates that the ore-bearing Duobuza granodiorite porphyry is high-K calc-alkaline to shoshonitic and peraluminous composition. The ore-bearing granodiorite porphyry is enriched in large-ion lithophile elements(LILE) such as Rb, K, Th, La, Ce and Sr, and depleted in high-field-strength elements(HFSE) such as Nb, Ta, P, and Ti. The rare-earth element (REE) patterns show enrichment in light REEs relative to heavy REEs. The major, rareearth, and trace elements of the ore-bearing granodiorite porphyry show characteristics of adakites, formed in an island arc setting. The laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb age of the orebearing granodiorite porphyry is 123.4±1.2 Ma (MSWD = 1.7), which also represents the age of the copper-mineralization. Together with the age data of the early Cretaceous magmatic rocks in the Bangongco–Nujiang suture zone and the middle-northern Gangdese, it indicates that there was bidirectional (northward and southward) subduction of the Bangongco–Nujiang ocean during 120 Ma, and the Duobuza deposit was related to this event.

In this study,we determined the granite ages in the middle to east Gangdese batholith. Zircon ages from these granites are 57.6–68.7 Ma,indicating that intrusions were formed in the Late Cretaceous to early Paleocene. The large-ion lithophile elements are highly enriched,whereas some high-field-strength elements are depleted. The Sr-Nd-Pb isotopic characteristics are similar to those of the Dianzhong volcanics in the Linzhou Basin,indicating the same origin and tectonic environment. The samples show positive εHf（t） values that are slightly lower than the values for the Linzizong volcanics,the Quxu intrusion,and other intrusions in middle Gangdese. We conclude that our samples,the Linzizong volcanics,and most main-collisional intrusions are derived from the same source with different ratios of crust and mantle input. On the basis of geological,geochemical,geochronological,and isotopic information,we conclude that the Late Cretaceous to Paleogene evolution of Gangdese can be divided into three stages. First,the collision began at 70–60 Ma,the same time as rollback of the Tethys Ocean slab. Second,during 60–50 Ma,slab breakoff triggered upwelling of the asthenosphere. Third,after 50 Ma,the Tethys Ocean slab’s effect disappeared and the interaction between Indian and Asian crusts began influencing magmatism in Gangdese.