Petrogenesis and Tectonic Significance of the Cuobuzha Peridotite,Yarlung Zangbo Suture Zone,China     

Guangying FENG  Jingsui YANG  Yildirim DILEK  Fei LIU  Fahui XIONG 《《地质学报》英文版》2019,93(Z2):8-8

The Yarlung Zangbo suture zone (YZSZ) in southern Tibet includes the remnants of Neo‐Tethyan oceanic lithosphere and marks a major suture between the Indian plate to the south and the Lhasa terrane of Tibet to the north. The upper mantle section of the Cuobuzha ophiolite in the northern subbelt of the western YZSZ comprises mainly clinopyroxene (cpx)‐rich and depleted harzburgites. Spinels in the cpx‐harzburgites show lower Cr^# values (12.6–15.1) than the spinels in the harzburgites (26.1–34.5), and the cpx‐harzburgites display higher heavy rare earth element concentrations than the depleted harzburgites. The harzburgites have subchondritic Os isotopic compositions (0.11624–0.11699), yielding Re‐depletion model ages (TRD) ages from 1.8 to 1.7 Ga, indicating that the Cubuzha mantle underwent at least one ancient melt extraction event ca. 1.8‐1.7Ga; whereas the cpx‐harzburgites have suprachondritic ¹⁸⁷Os/¹⁸⁸Os ratios (0.12831–0.13125) with higher Re concentrations (0.380–0.575 ppb), indicating subsequent addition of Re following the last partial melting event that occurred during mid‐ocean ridge melt evolution processes. Although these geochemical and isotopic signatures suggest that both peridotite types in the ophiolite represent mid‐oceanic ridge–type upper mantle units, their melt evolution trends reflect different mantle processes. The cpx‐harzburgites formed from low‐degree partial melting of a primitive mantle source, and they were subsequently modified by melt‐rock interactions in a mid‐oceanic ridge environment. The depleted harzburgites, however, were produced by remelting of the cpx‐harzburgites, which later interacted with mid‐oceanic ridge basalt– or island‐arc tholeiite–like melts, possibly in a trench–distal backarc spreading center. Our new isotopic and geochemical data from the Cuobuzha peridotites confirm that the Neo‐Tethyan upper mantle had highly heterogeneous Os isotopic compositions as a result of multiple melt production and melt extraction events during its seafloor spreading evolution.  相似文献   

Late Cretaceous tectonic switch from a Western Pacific‐ to an Andean‐Type continental margin evolution in East Asia,and a foreland basin development in NE China          下载免费PDF全文

Feng‐Qi Zhang  Yildirim Dilek  Han‐Lin Chen  Shu‐Feng Yang  Qi‐An Meng 《地学学报》2017,29(6):335-342

The early Cretaceous structure of NE China was a result of slab‐rollback‐driven extensional tectonics, characteristic of Western Pacific‐type continental margins. Oblique docking of a microcontinent along the Asian active margin in the early Late Cretaceous induced a compressional stress regime that brought about an Andean‐type continental margin development. Partitioning of contractional–transpressional strain across NE China produced a retroarc foreland basin system, comprising, from east to west, an orogenic wedge, a foredeep (Songliao basin), a forebulge (Great Xing'an Range) and a back‐bulge depozone (Hailar and Erlian basins). A sub‐circular lacustrine depozone in the pre‐existing Songliao basin evolved into a NNE‐trending depocentre near the forebulge and acquired a westward flowing fluvial–deltaic drainage system during the Campanian. Development of this retroarc foreland basin system signals a significant tectonic switch from a Western Pacific‐type to an Andean‐type continental margin evolution in the geological history of East Asia.  相似文献   

Variations in basaltic geochemistry along a propagating rift of the late Ordovician marginal basin of the West Norwegian Caledonides   总被引：1，自引：0，他引：1  

Furnes  Dilek  Skjerlie  Ryttvad  & Fonneland 《地学学报》1998,10(1):21-26

The late Ordovician Solund-Stavfjord ophiolite complex in the western Norwegian Caledonides records a multi stage seafloor spreading history of an Iapetus marginal basin and contains three structural domains with distinctive tectonomagmatic evolutionary paths. The NNE-trending Domain 1 consisting of high-level gabbro, sheeted dykes and extrusive rocks is interpreted to represent fossil oceanic crust developed along a spreading centre that propagated northwards into pre-existing oceanic crust in the marginal basin. Dyke swarms at the head of this inferred propagating rift range from primitive, high-MgO basalts to highly fractionated quartz-diorites. Southwards along-strike of Domain 1, the abundance of primitive basalts decreases and the proportion of FeTi-basalts increases to become predominant furthest behind the tip of the propagating rift. This geochemical evolution is comparable to that of the basalts of modern propagating rifts at the East Pacific Rise and the Galapagos spreading ridge. We suggest that the chemical variations of the metabasalts reflect changes in magma supply rates and in the increasing size of magma chamber(s) along-strike of the spreading centres.  相似文献   

西藏雅鲁藏布蛇绿岩形成构造环境的地球化学鉴别   总被引：9，自引：7，他引：2  

李文霞  赵志丹  朱弟成  董国臣  周肃  莫宣学  DePAOLO Don  DILEK Yildirim 《岩石学报》2012,28(5):1663-1673

本文对西藏雅鲁藏布蛇绿岩带中部日喀则地区夏鲁蛇绿岩中的基性岩石进行了元素地球化学研究。岩石为低钾亚碱性玄武质岩石,具有低TiO2(0.64%～1.5%)、低K2O(<0.69%)、富Na2O(2.5%～6.0%)、烧失量普遍较高(2.0%～7.5%)的特征,表明样品普遍遭受蚀变。岩石具有与N-MORB类似的稀土元素和总体一致的微量元素特征,但是岩石明显富集大离子亲石元素和亏损高场强元素,显示了洋脊玄武岩向着岛弧岩浆作用的过渡趋势。日喀则蛇绿岩不是典型的洋中脊成因,应为SSZ型蛇绿岩,可能形成于与洋内俯冲有关的SSZ型的弧后或者弧前盆地中。对东西延伸超过1500km的雅鲁藏布蛇绿岩246套基性岩石形成的构造环境进行的地球化学判别,表明至少存在大陆岛弧型、地幔柱-洋内热点型、洋中脊-大洋岛弧型和典型大洋岛弧型等四种类型洋壳,揭示了特提斯洋存在多种构造环境的特征,有利于恢复和还原一个长期演化的、丰富的特提斯洋。  相似文献   

西藏拉萨地块过铝质花岗岩中继承锆石的物源区示踪及其古地理意义   总被引：5，自引：2，他引：3  

朱弟成  赵志丹  牛耀龄  王青  管琪  刘勇胜  莫宣学 《岩石学报》2011,27(7):1917-1930

富含继承锆石的过铝质花岗岩一般来源于富铝质岩石(如变泥质岩)的部分熔融,因而分析这些继承锆石的U-Pb年龄可以像分析沉积岩碎屑锆石的U-Pb年龄一样,提供过铝质花岗岩源区物质中碎屑沉积物物源区的丰富信息。本文报道了中部拉萨地块早侏罗世过铝质花岗岩的全岩地球化学和锆石U-Pb年代学数据,结合拉萨地块已有二叠纪和晚三叠世过铝质花岗岩的继承锆石年代学数据,总结了目前已有的拉萨地块过铝质花岗岩的继承锆石U-Pb年龄特征(共199个谐和测点)。这些过铝质花岗岩属强过铝质S型花岗岩,其中的继承锆石定义了1250~1100Ma(峰值1181±14Ma)和550~450Ma(峰值494±7Ma)2个最突出的年龄群,分别可比于拉萨地块古生代沉积岩的碎屑锆石年龄峰值(约1170Ma)和寒武纪火山岩的侵位时代,明显不同于西羌塘、安多和特提斯喜马拉雅新元古代-古生代沉积岩中的碎屑锆石年龄频谱。拉萨地块过铝质花岗岩中约1181Ma的继承锆石,可能与拉萨地块古生代沉积岩中的同期碎屑锆石一样,都来自澳大利亚南西部Albany-Fraser造山带和东南极Wilkes等地,而约494的继承锆石,既可能来自澳大利亚西部,也可能来自拉萨地块本地。本文提供了拉萨地块与澳大利亚大陆北缘具有古地理联系的过铝质花岗岩继承锆石U-Pb年龄证据。拉萨地块的研究实践表明,采用过铝质花岗岩继承锆石和古生代沉积岩碎屑锆石相结合的锆石U-Pb年代学方法,可为重建冈瓦纳大陆北缘其它微陆块的古地理和构造岩浆演化提供重要约束。  相似文献   

Failure and flow development of a collapse induced complex landslide: the 2005 Kuzulu (Koyulhisar, Turkey) landslide hazard   总被引：1，自引：0，他引：1  

Işık Yilmaz  Tülay Ekemen  Mustafa Yildirim  İnan Keskin  Gül Özdemir 《Environmental Geology》2006,49(3):467-476

Koyulhisar located in a slope of hilly region and constructed in the side of a mountain along the North Anatolian Fault Zone is frequently subject to landslides. A catastrophic landslide occurred on the morning of 17 March 2005 in the North of the Kuzulu district of Koyulhisar (Sivas, Turkey). This landslide caused widespread loss of life, and damage to buildings, and lifelines. Fifteen people were dead and five were injured, 21 houses and a minaret were covered and damaged severely. The case study presented in this paper describes and analyses the results of the detailed surveys of an interesting landslide in Kuzulu district of Koyulhisar (Sivas, Turkey), based on field and laboratory measurements and monitoring of the slide area. Landslide initiated as a collapse, and developed into debris avalanches in the valley. This phenomenon caused a disaster in the Kuzulu district. The importance of this landslide in particular has been recognized both in terms of its consequence for the people and structures and in terms of its role in allowing an understanding of process and properties of landslide triggered by a collapse in limestone karst. In view of the potential for such events to occur again in this area and environs, understanding of the failure mechanism is very crucial.  相似文献   

Development of Polymeric and Polymer‐Based Hybrid Adsorbents for Chromium Removal from Aqueous Solution     

Ismet Gul Buyruklardan Kaya  Dilek Duranoglu  Ulker Beker  Bahire Filiz Senkal 《洁净——土壤、空气、水》2011,39(11):980-988

Ferric oxide‐loaded hybrid sorbents are environmentally benign and exhibit sorption behaviors for chromium removal from waters. In the current study, glycidyl methacrylate‐based polymer (GMD) and nanosized ferric oxide loaded glycidyl methacrylate‐based polymer (GMDFe) were prepared and assayed to examine the effect of ferric oxide loading on chromium sorption from aqueous solution for the first time from the equilibrium and kinetic points of view. The experimental equilibrium data, suitably fitted by the Langmuir and Freundlich isotherms, have shown that ferric oxide loaded hybrid sorbent exhibits higher adsorption capacity than glycidyl methacrylate‐based polymer (GMD). The Langmuir isotherm model was found to be the most suitable one for the Cr(VI) adsorption. The maximum adsorption capacities of GMD and GMDFe sorbents were determined at pH 4 as 109.54 and 157.52 mg/g, respectively. A series of column experiments was carried out to determine the breakthrough curves. The column was regenerated by eluting Cr(VI) using NaOH (10% w/v) solution after adsorption studies.  相似文献   

Community structure of epiphytic algae on three different macrophytes at Acarlar floodplain forest （northern Turkey）   总被引：2，自引：2，他引：0  

Hatice TUNCA Tugba ONGUN SEVINDIK Dilek Nur BAL Sevil ARABACI 《中国海洋湖沼学报》2014,32(4):845-857

The aim of this study was to determine the species composition, biodiversity and, relative abundance of epiphytic algae and their relationship with environmental variables on three different macrophytes( Nymphaea alba, Ceratophyllum demersum, Typha latifolia) at Acarlar Floodplain Forest(AFF). Epiphytic algae were gathered monthly by collecting aquatic plants between November 2011 and October 2012, except in winter when there were no plants. In this study, 67 taxa on N. alba, 66 taxa on C. demersum and 66 taxa on T. latifolia were identified as epiphytic algae. The mean value of species richness was 17, that of diversity was 1.5 and that of evenness was 0.54 for epiphytic algae on N. alba, 17, 1.1, and 0.39 on C. demersum, and 18, 1.64, and 0.56 on T. latifolia, respectively. Oscillatoria sp. and Komvophoron crassum(Vozzen) Anagnostidis and Komárek were the most abundant and consistent epiphytic algal species, occurring in high abundance on all macrophytes. Results show that species composition of epiphytic algae was different, but diversity values were similar on all the macrophytes. The hydrological pulse is one of the most important factors determining the physical and chemical environment of the epiphytic algal community. However, substrate type also affected the colonization by F. capucina, O. sancta, P. catenata, and L. truncicola more than the epiphytic algal seasonality.  相似文献   

A Study: Removal of Cu(II), Cd(II), and Pb(II) Ions from Real Industrial Water and Contaminated Water Using Activated Sludge Biomass     

Erdal Kusvuran  Deniz Yildirim  Ali Samil  Osman Gulnaz 《洁净——土壤、空气、水》2012,40(11):1273-1283

This study aims to remove of Cu²⁺, Cd²⁺, and Pb²⁺ ions from solution and to investigate the adsorption isotherms, adsorption kinetics, and ion‐exchange affinities of these metals using waste activated sludge (AS) biomass. The adsorptions of the metals on biomass were optimal at an acidic pH value of 6.0 based on its monolayer capacities. Maximum monolayer capacities of AS biomass (q_max) were calculated as 0.478, 0.358, and 0.280 mmol g^?1 for Cu²⁺, Cd²⁺, and Pb²⁺, respectively, and the adsorption equilibrium time was found as 60 min for each metal. The adsorbed amount of metal rose with increasing of initial metal ion concentration. The equilibrium adsorption capacity of AS for initial 0.25 mmol L^?1 metal concentration was determined as 0.200, 0.167, and 0.155 mmol g^?1 for Cu²⁺, Cd²⁺, and Pb²⁺ ions, respectively. These relevant values were determined as 0.420, 0.305, and 0.282 mmol g^?1 for Cu²⁺, Cd²⁺, and Pb²⁺ ions, respectively, when initial metal concentration was 0.50 mmol L^?1. In the multi‐metal sorption system, the adsorption capacity of AS biomass was observed in the order of Cu²⁺ > Cd²⁺ > Pb²⁺. In the presence of 100 mmol L^?1 H⁺ ion, the order of ion‐exchange affinity with H⁺ was found as Cu²⁺ > Cd²⁺ > Pb²⁺. The adsorption kinetics were also found to be well described by the pseudo‐second‐order and intraparticle diffusion models. Two different rate constants were obtained as k_i1 and k_i2 and k_i1 (first stage) was found to be higher than k_i2 (second stage).  相似文献   

Kalaymyo Peridotite Massif in the Indo-Myanmar Ranges (Western Myanmar): Its Mineralogy and Petrology     

NIU Xiaolu  LIU Fei  YANG Jingsui  Yildirim DILEK  XU Zhiqin  FENG Guangying  XIONG Fahui  Kyaing SEIN 《《地质学报》英文版》2017,91(Z1):24-25

Mesozoic ophiolites crop out discontinuously in the Indo-Myanmar Ranges in NE India and Myanmar,and represent the remnants of the Neotethyan oceanic lithosphere(Sengupta et al.,1990;Mitchell,1993).These ophiolites in the Indo-Myanmar Ranges are the southern continuation of the Neotethyan ophiolites occurring along the Yarlung Zangbo Suture Zone(YZSZ)in southern Tibet farther northwest(Mitchell,1993;Fareeduddin and Dilek,2015),as indicated by their coeval crystallization ages and geochemical compositions(Yang et al.,2012;Liu et al.,2016).The Kalaymyo ophiolite is located in the central part of the eastern Indo-Myanmar Ranges(Fig.1).composition of these ophiolites from the central Tibetan Plateau(CTP)is dominated by MORBs and minor OIBs and a distinct lack of IATs and BONs,which is inconsistent with most ophiolites worldwide(Robinson and Zhou,2008;Zhang et al.,2008).But the generation and tectonic nature of these ophiolites are still controversial.*The Kalaymyo peridotites consist mainly of harzburgites,which show typical porphyroclastic or coarse-grained equigranular textures.They are composed ofolivine(Fo=89.8–90.5),orthopyroxene(En86-91Wo1-4Fs8-10;Mg#=89.6–91.9),clinopyroxene(En46-49Wo47-50Fs3-5;Mg#=90.9–93.6)and spinel(Mg#=67.1–78.9;Cr#=13.5–31.5),and have relatively homogeneous whole-rock compositions with Mg#s of90.1–90.8 and Si O2(41.5–43.65 wt.%),Al2O3(1.66–2.66wt.%)and Ca O(1.45–2.67 wt.%)contents.TheydisplayLightRareEarthElement(LREE)-depleted chondrite-normalized REE patterns with(La/Yb)CN=0.04–0.21 and(Gd/Yb)CN=0.40–0.84,and show a slight enrichment from Pr to La with(La/Pr)CN in the range of 0.98–2.36.The Kalaymyo peridotites are characterized by Pd-enriched chondrite-normalized PGE patterns with superchondritic(Pd/Ir)CN ratios(1.15–2.36).Their calculated oxygen fugacities range between QFM–0.57 and QFM+0.90.These mineralogical and geochemical features collectively suggest that the Kalaymyo peridotites represent residual upper mantle rocks after low to moderate degrees(5–15%)of partial melting at a mid-ocean-ridge(MOR)environment.The observed enrichment in LREE and Pd was a result of their reactions with enriched MORB-like melts,percolating through these already depleted,residual peridotites.The Kalaymyo and other ophiolites in the Indo-Myanmar Ranges hence represent mid-ocean ridge(MOR)–type Tethyan oceanic lithosphere derived from a downgoing plate and accreted into a westward migrating subduction–accretion system along the eastern margin of India.  相似文献