对西秦岭地区中川岩体、柏家庄岩体和教场坝花岗岩体进行LA-ICP-MS锆石U-Pb同位素年代学分析,获得其岩浆侵位年龄分别为220±1,216±6和222±3 Ma,表明3个岩体均形成于中-晚三叠世.样品的全岩地球化学分析结果表明,3个岩体具有相似的稀土及微量元素特征,均表现为显著亏损高场强元素Nb,Ti和P等,具有明显的右倾式球粒陨石标准化稀土元素配分模式.锆石Lu-Hf同位素分析结果表明,3个岩体锆石测年样品的εHf(t)值介于?3.31～+1.68之间,二阶段模式年龄介于1151～1456 Ma之间.岩石成因分析表明,这些印支期花岗岩体的母岩浆主要来源于新元古代地壳物质的部分熔融.结合岩体形成时代、岩石成因和区域岩浆作用,认为这些岩体形成于南秦岭与华南板块沿勉略缝合带相碰撞的造山动力学背景,可能与华南板块的俯冲板片断离有关.

抱伦金矿床位于海南岛西南部的五指山褶皱带内.矿体呈脉状、透镜状存在于志留系陀烈组的含炭绢云母千枚岩中,主要受NNW向断裂带控制.矿物组合特征表明成矿过程主要分为乳白色粗粒石英—烟灰色细粒石英—碳酸盐和绿泥石3个成矿阶段,中成矿阶段是主要的成矿期,发育自然金、铋碲化物和硫化物.石英中的流体包裹体测试结果显示:① 包裹体发育类型相对简单,主要为CO 2-H 2 O包裹体(C型)和水溶液(W型)两种,均一温度变化在130℃～380℃范围内,盐度w(NaCleq)集中在0.2％～11.7％;② 不同成矿阶段流体特征不同,早期变质流体具有温度中等、盐度较低的特点,中期具有变质流体和岩浆流体的混合流体特征,成矿流体温度、盐度小幅升高,晚期大气降水参与的热液流体以低温、低盐度为主;③ 液态不混溶作用主要发生在早、中成矿阶段流体中,致使自然金大量沉淀.综合矿产地质特点及流体演化规律分析,海南抱伦金矿具有非典型的造山型金矿的特征,印支期尖峰岭岩体花岗质岩浆流体参与的混合作用对于抱伦金矿床富集和沉淀有着重要贡献.

LA-ICP-MS zircon U-Pb dating for Daning pluton, dark inclusions and Chudong pluton yield the weighted mean206Pb/238Pb ages of 441.1±3.0 Ma, 439.5±3.6 Ma and 423.5-434.2 Ma, respectively, revealing that Daning pluton and the dark inclusions were formed almost concurrently, while the Daning pluton was intruded by the Chudong pluton. In-situ zircon Lu-Hf isotopic analyses of Daning pluton, dark inclusions and Chudong pluton show same characteristics with negativeεHf(t) values, plotted within the revolution areas of the 1440-1960 Ma old continental crust in the age vs.εHf(t) diagrams. The Hf isotopic characteristics indicate that the magmas could be derived from the partial melting of Early Proterozoic to Mesoproterozoic crust materials. The dark inclusions were produced by the fractional crystallization of parental magma. The Chudong pluton was the advanced stage product of the magma crystallization differentiation.

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.

According to the dislocation theory in elastic infinite half-space and the geometric and kinematic characteristics of active faults,based on the coseismic rupture models of Wenchuan and Lushan earthquakes,changes of static Coulomb stress induced by Wenchuan earthquake in 2008 were calculated by Coulomb software,and were compared with the distribution of aftershocks;changes of static Coulomb stress jointly induced by Wenchuan earthquake in 2008 and Lushan earthquake in 2013 were calculated,and were projected onto main active tectonics in the eastern edge of Qinghai-Tibet Plateau.The results show that most of aftershocks occur in the increase area of static Coulomb stress induced by Wenchuan earthquake;static Coulomb stresses induced by Wenchuan earthquake increase 0.010-0.050 MPa significantly in the epicenter area of Lushan earthquake,and change of static Coulomb stress induced by Wenchuan earthquake leads to the earlier occurrence of Lushan earthquake;static Coulomb stresses of the northern part of Xianshuihe,East Kunlun,the western segment of Qinling southern frontal,the eastern part of Qingchuan,the western part of Chaba-Lin??ansi,Guanxian-Jianyou and Dachuan-Shuangshi faults increase at different levels;static Coulomb stresses of Minjiang,Huya,Wenchuan-Maoxian,Jiangyou-Guangyuan and the southern part of Xianshuihe faults decrease at different levels;considering the distribution of historical great earthquakes and their aftershocks in the eastern edge of Qinghai-Tibet Plateau,monitor and research on the seismic risk in the northwestern part of Xianshuihe fault and East Kunlun fault should be strengthened in future.

We have determined the ages of the ore-bearing Tinggong porphyries and the Eocene granites using the LA-ICPMS zircon U-Pb method. Zircons from one adamellite porphyry and two diorite porphyries yield ages of 15.54±0.28 Ma, 15.02±0.25 Ma and 14.74±0.22 Ma, respectively. The ages of two granites are 50.48±0.71 Ma and 50.16±0.48 Ma. Light Rare Earth Elements（LREE） are enriched in the ore-bearing adamellite porphyries, which are high-K calc-alkaline and metaluminous, while Heavy Rare Earth Elements（HREE） and Y are strongly depleted, indicating an adakitic affinity. The Large Ion Lithophile Elements（LILE） of the adamellite porphyries are highly enriched, whereas some High Field Strength Elements（HFSE） are depleted. The diorite porphyry in this study is chemically similar to the adamellite porphyries, except that the Mg# of the diorite porphyry is a little higher, demonstrating more mantle contamination. Four samples from different rocks are selected for in situ zircon Hf isotopic analyses. The samples show positive εHf（t） values and young Hf model ages, indicating their derivation from juvenile crust. However, the adamellite porphyry and diorite porphyry formed in the Miocene exhibit more heterogeneous Hf isotopic ratios, with lower εHf（t） values than the granites formed in the Eocene, suggesting the involvement of old Indian continent crust in their petrogenesis. The geochronology and geochemistry of the adamellite porphyries and the diorite porphyries indicate that they formed from the same source region in a post-collisional environment, but contaminated by crust and mantle materials in different ratios. The metallic minerals formed mainly during the older adamellite porphyry stage, but they were recycled and reactivated by the diorite porphyry intrusion.

The Gangdese belt, Tibet, records the opening and closure of the Neo-Tethyan ocean and the resultant collision between the Indian and Eurasian plates. Mesozoic magmatic rocks generated through subduction of the Tethyan oceanic slab constitute the main component of the Gangdese belt, and play a crucial role in understanding the formation and evolution of the Neo-Tethyan tectonic realm. U–Pb and Lu–Hf isotopic data for tonalite and granodiorite from the Xietongmen–Nymo segment of the Gangdese belt indicate a significant pulse of Jurassic magmatism from 184Ma to 168Ma. The magmatic rocks belong to metaluminous medium-K calc-alkaline series, characterized by regular variation in major element compositions with SiO2 of 61.35%–73.59%, low to moderate MgO (0.31%–2.59%) with Mg# of 37–45. These magmatic rocks are also characterized by LREE enrichment with concave upward trend in MREE on the chondrite-normalized REE patterns, and also LILE enrichment and depletion in Nb, Ta and Ti in the primitive mantle normalized spidergrams. These rocks have high zircon εHf(t) values of +10.94 to +15.91 and young two-stage depleted mantle model ages (TDM2) of 192Ma to 670Ma. The low MgO contents and relatively depleted Hf isotope compositions suggest that the granitoid rocks were derived from the partial melting of the juvenile basaltic lower crust with minor mantle materials injected. In combination with the published data, it is suggested that northward subduction of the Neo-Tethyan slab beneath the Lhasa terrane began by the Late-Triassic, which formed a major belt of arc-related magmatism.

We have determined the ages of the ore-bearing Bangpu porphyries and the age of formation of an associated Mo–Cu ore deposit using the LA–ICPMS zircon U–Pb and the molybdenite Re–Os methods. Zircons from two adamellite porphyries give ages of 14.07±0.08Ma and 14.96±0.16Ma, and zircons from a diorite porphyry give an age of 15.30±0.25Ma. The ages of three molybdenite samples are 14.96±0.23Ma, 15.08±0.23Ma and 16.61±0.23Ma. Light Rare Earth Elements (LREE) are enriched in the ore-bearing adamellite, which is shoshonitic and peraluminous, while Heavy Rare Earth Elements (HREE) and Y are strongly depleted, indicating an adakitic affinity. In contrast to other deposits formed in the post-collisional Gangdese belt, the Rb/Sr ratio in Bangpu is high, demonstrating more crustal contamination. The geochemistry of the ore-bearing diorite porphyry differs significantly from that of the ore-bearing adamellite. The diorite porphyry displays a reverse slope in its REE (Rare Earth Element) pattern, and is shoshonitic and metaluminous. The geochronology and geochemistry of both ore-bearing rocks indicate that the Bangpu ore deposit is related to two different source regions in a post-collisional environment. The metallic minerals formed mainly during the older diorite porphyry stage, but they were recycled and reactivated during adamellite magmatism. The sources of the mineralising fluids, and the evolution of the northern GPCB (Gangdese Porphyry Copper Belt), where the Bangpu ore deposit is located, are more complex than in the southern GPCB.

Molang intrusion, located north of Sangye Temple, Zedang Town, represents the middle part of the Gangdese magmatic belt. Lithological assemblage is composed principally of pyroxene diorite, diorite, granodiorite and K-feldspar granite. Detailed LA-ICP-MS zircon U-Pb geochronological and petrogeochemical studies are presented in this paper. Granodiorite and K-feldspar granite were emplaced at 57Ma and characterized by high SiO2(70.1%~74.4%), low to high K2O (1.3%~5.2%), and low MgO (0.2%~1.2%) contents as well as distinctly negative Eu and Sr anomalies. The Zr/Nb-Zr and AFM-CFM diagrams indicate derivation of the granodiorite and K-feldspar granite by low-degree partial melting of juvenile crust and metagreywacke. In contrast, pyroxene diorite, diorite were crystallized at 52~54Ma and characterized by low SiO2 (53.2%~58.6%), middle to high K2O (1.3%~2.5%), and high MgO (3.2%~3.9%) contents with weakly to obviously negative Eu and Sr anomalies. These characteristics are analogous to those of the intermediate to basic intrusions of the Quxu batholith. We suggest that they were produced by magma mixing between mantle-derived materials and partial melts derived from remelting of juvenile crust.

There is a great thickness of bathyal- and slope-facies volcanic-volcaniclastic sedimentary sequence at Baogutu area in southeast of western Junggar, which are named as Tailegula Formation, Baogutu Formation and Xibeikulas Formation, respectively. There have been controversies about the geological ages and stratigraphic subdivision about these strata for a long time. So we surveyed the stratum section at Baogutu area and separated zircons from basalt of the Tailegula Formation and tuff of Baogutu Formation and Xibeikulas Formation. LA-ICP-MS U-Pb dating on these zircon grains gives the 206Pb/238 U weighted mean ages of 357. 5 ± 5. 4Ma, 332. 1 ± 3. 0Ma and 336.3 ± 2. 5Ma, respectively, indicating that the strata sequence from bottom to top should be Tailegula Formation, Baogutu Formation and Xibeikulas Formation in turn, which were formed from Tournaisian to Visean of Early Carboniferous.

在大量薄片鉴定的基础上,本文对包古图斑岩铜矿的钛矿物组合特征及其形成机制进行了研究.主要钛矿物为榍石、钛铁矿和金红石.其中榍石在成岩期和成矿期均有形成,但主要见于成矿期的钾化阶段,与钾长石、黑云母共生;在后期的青盘岩化和沸石化阶段也有出现,但含量相对较少.成岩期的钛铁矿很少见,成矿期各蚀变阶段均有分布,但最常见于钾化阶段.金红石仅见于成矿期,钾化阶段早期可与钾长石、黑云母、石英等共生,还见有被榍石包裹的细粒金红石,青盘岩化阶段亦有形成,与绿泥石共生.这些钛矿物最常出现于黑云母颗粒内部或其附近,这可能是斑岩型矿床的特征之一.榍石SiO2和CaO含量与理论值接近,TiO2偏低;钛铁矿均含锰,MnO含量1.97%～4.49%,还见有锰钛铁矿;金红石含有一定量的SiO2和FeOT,个别颗粒还含有少量Al2O3、MgO和P2O5.钛矿物组合特征表明包古图含矿斑岩为Ⅰ型,形成于较高氧逸度环

西准噶尔包古图铜矿是近几年新疆发现的又一个中型斑岩铜矿,其成岩成矿年代学的研究可以对矿床成因、区域成矿规律的认识有更好的制约.包古图地区出露一系列中酸性小岩体,前人按照出露面积大小将这些岩体编号为Ⅰ～Ⅹ号.目前,Ⅴ号岩体已经进行了详勘,探明为中型铜矿,其他几个岩体也都程度不同的投入了勘探工作量,并且发现了较好的成矿迹象.本文利用锆石SHRIMP U-Pb法和单矿物K-Ar法对Ⅴ号岩体进行了成岩成矿年代学研究,其中锆石25个测点的206Pb/238U SHRIMP 年龄大致可以分为加权平均值(335.6±7.8)Ma和(311.4±3.3)Ma的两组,前者被解释为捕获锆石,可能来源于包古图组凝灰岩或者深部的花岗质岩基,有待于进一步研究;后者为含矿岩体侵位年龄.本次研究获得成矿期黑云母的K.Ar年龄为(296.0±3.7)Ma和(297.3±3.8)Ma,结合我们以前所获得的辉钼矿Re-Os年龄310 Ma,确定成矿时代为310～296 Ma.花岗斑岩和闪长玢岩脉的K-Ar年龄为278～240 Ma,根据穿插关系可以判定它们为成矿后脉岩.据此基本建立了包古图斑岩铜矿成岩成矿年代学框架.

伊吾县铜华岭中酸性侵入体位于新疆北部东准噶尔阿尔曼太断裂和克拉麦里断裂之间的野马泉岛弧区,岩性主要为闪长玢岩、英云闪长岩和二长花岗岩等.通过锆石LA-ICP-MS U-Pb年代学方法,对这3种岩性进行精确定年,其206Pb/238U的加权平均年龄分别为427.4±3.2,422.8±3.2和418.5±2.6 Ma,说明铜华岭岩体是早古生代岩浆活动的产物,为东准噶尔早古生代造山带演化提供了花岗岩证据.

Geochronology of Mesozoic volcanic rocks in Shandong province has direct connections with many major geological events in eastern China. In this study, volcanic rocks used for K-Ar dating are systematically sampled from four formations of Qingshan Group in the standard section of Jiaolai basin, and from Tianjialou Formation of Dasheng Group in Anqiu, as well as from Zibo, Mengyin and Juxian area. K-Ar dating of volcanic rock samples from Qingshan group shows that the age of this group ranges from 118Ma to 93Ma, corresponding middle to upper Cretaceous, and the ages of the four formations in this group are as follows: Houkuang Formation started from about 117Ma, belonging to Aputian; Bamudi Formation 109 similar to 103Ma, belonging to Albian; Shiqianzhuang Formation 103.7 similar to 93.3Ma, seated at upper Albian to Cenomanian, its bottom is about the top of Bamudi Formation, probably no discontinuity between the two formations; and Fanggezhuang Formation started from 93.3Ma, belonging to upper Cretaceous Turonian. Although difference has been existed, the age of Bamudi Formation vocanic rock in eastern Shandong Province is about the same of that in western Shandong Province. The age of lower Tianjialou Formation in Dasheng Group is similar to 95Ma, corresponding to upper Shiqianzhuang Formation of Qinshan Group, indicating that the two groups are crossed-correpondence. Volcanic rocks of Fangzi Formation of Zibo Group have early Cretaceous ages (107.7Ma and 120.1Ma), indicating that Jurassic volcanic rocks may be absent in Shandong.

The Precambrian Sushui Complex in Zhongtiao Mountain is composed principally of Xiyao and Zhaizi TTG gneisses, Henglingguan and Beiyu calc-alkaline granitoids.SHRIMP zircon U-Pb dating for Xiyao TTG gneiss yield the weighted mean ~(207)Pb/~(206)pb age of 2536±8Ma,revealing that it was formed in the Neoarchean.In-situ zircon Lu-Hf isotopic analyses of Xiyao and Zhaizi TTG gneisses and Henglingguan-Beiyu calc-alkaline granitoids show that the magmatic zircons have positiveε_(Hf)(t) values,and theseε_(Hf)(t) values are plotted within the revolution areas of the 2600～3100Ma old continental crust in the age vs.ε_(Hf)(t) diagrams. The analytical spots of three inherited zircon cores from the Beiyu calc-alkaline granitoid yield a weighted mean ~(207)Pb/~(206)pb age of 2633±84Ma,and theε_(Hf)(t) values of these inherited cores of magmatic zircon grains are,-2.0～+5.6.The characteristics of zircon SHRIMP U-Pb ages and Hf isotope compositions of these TTG gneisses and calc-alkaline granitoids from the Precambrian Sushui Complex indicate that they were possibly formed in the Neoarchean to Paleoproterozoic tectonic settings of Andes-type continent margin, and the magmas could be derived from the partial mehing of juvenile crust materials from the depleted mantle and more older continental crust materials.

近年来,重要的斑岩铜矿--冈底斯大型斑岩铜矿带被发现(侯增谦等,2001;李光明等,2004;芮宗瑶等,2006)以来,在其北部的念青唐古拉成矿带相继发现了多处大型铅-锌多金属矿床,代表性矿床有拉屋铜多金属矿、勒青拉铜多金属矿、尤卡朗银多金属矿、亚贵拉多金属矿和洞中松多银多金属矿等.其中亚贵拉多金属矿是河南地质调查院新发现的一个超大型矿床.

While testing capability of mass spectrometer has been improved, sample fusion system becomes the main factor to effect Ar isotopes determination. Sample tube has been reconstructed from mono-tube to multiple-tube. After reconstruction, it allowes us to remove atmosphere Ar and measure hot blank beforehand. This reduces the influence of non-radiogenic Ar to measuring results,which plays an important role especially to young volcanic rocks. Moreover, measuring time is saving. The second change that has made is quartz tube from cylinder-shape to three-pinstripe. Quartz material contacted to the molybdenum crucible reduces to one fifth. This makes hot blank even lower and the removal time is shorter. After modification of sample tube, the content of radiogenic Ar increases and reproducibility and accuracy of standards is better.

新疆西准噶尔包古图斑岩铜矿床Au平均含量0.25 g/t,Ag为2.56 g/t,Cu为0.30%,属于富金斑岩铜矿.伴生金和银矿化作用有两期:早期为斑岩矿化,形成了Cu-Mo-Au矿化组合,是主矿化期;后期叠加了Cu-Au-Ag-Te-Bi矿化,规模不大,出露于矿床的局部部位,但对矿石起到了加富作用.通过对钻孔薄片和光薄片的镜下观察及电子探针成分分析,认为早期矿化中Au和Ag主要呈固溶体形式存在于硫化物中,分布比较均匀,基本上不出现独立矿物,Au含量明显高于Ag;晚期矿化形成了复杂的Cu-Au-Ag-Te-Bi矿物,矿石呈浸染状和脉状叠加在早期矿化之上,以银矿物为主,与多种碲铋类矿物共生,主要银矿物有碲银矿、铋-碲银矿(?)、银-辉碲铋矿(?)、银-硫铋铜矿、银金矿等.晚期矿化规模不大,但对于提高矿床的经济价值具有重要意义.

近几年来,冈底斯成矿带发现了多个大型一超大型斑岩型铜矿床,同时在其外围还发现了知不拉、甲马等产于夕卡岩中的多金属矿床(王方国等,2005).这类夕卡岩矿床的成因一直存在争议,主要有海底喷流热水成矿说和岩浆一热液交代成矿说(李光明等,2005;杜光树等,1998;冯孝良等,2001;姚鹏等,2006).硫化物矿床的矿物组合研究不仅对于矿床的开采冶炼具有重要意义,同时对于矿床的形成机制及其成因研究也具有重要作用(Cook,1996).本文重点介绍在知不拉矿床新鉴定出的多种稀少金属矿物,并对其成因意义进行初步探讨.