西藏芒康盆地新生代高钾火山岩的主元素和同位素地球化学研究   总被引：6，自引：4，他引：2  

朱丽  张会化  王江海  解广轰 《大地构造与成矿学》2005,29(4):502-511

元素和Pb-Sr-Nd同位素地球化学示踪结果表明,西藏芒康盆地内拉屋乡组高钾火山岩是在转换压缩引起的陆内俯冲背景下产生的,其可能源区为EMII型富集地幔端元。高场强元素Nb和Ta出现明显的负异常,表明在该火山岩源区内有陆壳物质的加入。稀土元素模拟结果显示岩浆源区成岩过程中有单斜辉石、斜长石和石榴子石的分离结晶。  相似文献   

Petrological characteristics of the Damiao anorthosite complex in Hebei Province,China     

Guanghong Xie 《中国地球化学学报》1982,1(4):369-386

The Damiao anorthosite complex occurs in the high-grade metamorphic Precambrian rocks in the axial part of the Nei Mongol (Inner Mongolia) Anticline. It is a monoclinal, layered intrusion, with distinguishable layers of anorthosite, monzonite and quartz-monzonite from bottom to top. Gradation evidence can be noticed between these layers. Accumulation structure is obvious in anorthositic rocks. In the anorthositic rocks feldspars, mainly antiperthite and plagioclase, are hosted with An 44–49, while in the acid rock facies, perthite and plagioclase are present. The complex investigated can be assigned to andesine-type rocks. Both the Damiao anorthosites and the Miyun rapakivi granites are calc-alkaline in terms of petrochemical characteristics, and the latter exhibits a very close petrochemical similarity, i.e., high in Al and K, with the acid members in the upper layers of the complex at Damiao. In view of the close temporal-spatial relationship and the resemblance of rock structure, it is thought that the two suites are resulted from a single parent magma under approximate tectonic environments, and that gravitative fractionation may have played an important role in their evolution. Calculations show that the parent magma responsible for the suites bears obvious resemblance to quartz diorite and quartz monzonite in composition, which is in agreement with the experiments by T. H. Green. The Damiao anorthosite complex is characterized by deep source and shallow emplacement as evidenced by high-pressure and high-temperature experiments, geothermometry and petrochemical features as well as the occurrence of both pigeonite and primary “Al-pyroxene”.  相似文献   

Geochemical Records of Mantle Processes in Mantle Xenoliths from Three Cenozoic Basaltic Volcanoes in Eastern China     

MASUSDA Akimasa 《《地质学报》英文版》2004,78(5):1109-1121

Rare earth element (REE) contents, and Sr and Nd isotopic compositions were measured for three suites of mantle xenoliths from the Kuandian, Hannuoba and Huinan volcanoes in the north of the Sino-Korean Platform. From the correlations of Yb contents with Al/Si and Ca/Si ratios, the peridotites are considered to be the residues of partial melting of the primitive mantle. The chondrite-normalized REE compositions are diverse, varying from strongly LREE-depleted to LREE-enriched, with various types of REE patterns. Metasomatic alteration by small-volume silicate melts, of mantle peridotites previously variably depleted due to fractional melting in the spinel peridotite field, can account for the diversity of REE patterns. The Sr/ Ba versus La/Ba correlation indicates that the metasomatic agent was enriched in Ba over Sr and La, suggestive of its volatile-rich signature and an origin by fluid-triggered melting in an ancient subduction zone. The Sr and Nd isotopic compositions of these xenoliths, even from  相似文献   

辽宁宽甸黄椅山玄武岩中地幔岩捕虏体的REE 及 Sr、Nd 同位素地球化学   总被引：1，自引：0，他引：1       下载免费PDF全文

刘从强  解广轰 《地质科学》1993,28(3):228-234

报道了黄椅山玄武岩中三类地幔岩捕虏体的 REE 丰度和 Sr、Nd 同位素组成。研究分析认为:尖晶石二辉橄榄岩是地幔岩经不同程度部分熔融的残留体;角闪石二辉橄榄岩系地幔交代作用的结果;石榴石二辉岩是在地幔条件下基性岩浆的分凝体。上述捕虏体均与寄主玄武岩无成因关系。地幔岩捕虏体的 Sm-Nd 计时获得741Ma 和78Ma 两条参考等时线,它们分别相当于晚元古代和晚中生代的地幔事件。  相似文献   

OZ—IA—S臭氧探测器使用方法的比较结果     

张文煜  冯文泓 《高原气象》1995,14(4):495-498

关于ＯＺ－ＩＡ－Ｓ臭氧探测器在野外观测中所获数据的精度问题，我们对其观测方法进行了比较分析。结果表明，该仪器是一种灵敏度很高的仪器，每次使用前都应清洗扩散器，在使用时用干燥好的固体过滤器过滤，以得到准确的数据。  相似文献   

Diagnostic calculation of the upper-layer circulation in the South China Sea during the winter of 1998   总被引：4，自引：0，他引：4  

YUAN Yaochu  BU Xianwei  LIAO Guanghong  LOU Ruyun  SU Jilan  WANG Kangshan 《海洋学报(英文版)》2004,23(2):187-199

On the basis of hydrographic data obtained in November 28 to December 27, 1998 cruise, the calculation of the circulation in the South China Sea (SCS) is made by using the P-vector method, in combination with SSH data from TOPEX/ERS-2 analysis. For study of the dynamical mechanism, which causes the pattern of winter circulation in the SCS, the diagnostic model (Yuan et al., 1982; Yuan and Su, 1992) is used to simulate numerically the winter circulation in the SCS. The following results have been obtained. (1) The main characteristics of the circulation systems in the central SCS are as follows: A coastal southward jet in winter is present at the western boundary near the coast of Vietnam; there is a stronger cyclonic circulation with a larger horizontal scale east of this coastal southward jet and west of 114°E; there is a weaker anti-cyclonic circulation in the central part of eastern SCS; there is a stronger and northeastward flow opposing the northeasterly monsoon between above a stronger cyclonic c  相似文献   

黑河张掖段浮游植物群落结构及其与环境因子的关系   总被引：3，自引：2，他引：1  

杨宋琪  祖廷勋  王怀斌  王丽娟  陈天仁  王丹霞  杨生辉  罗光宏 《湖泊科学》2019,31(1):159-170

为探究黑河张掖段浮游植物群落季节动态及其与环境因子的相互关系,于2017年对黑河张掖段10个断面进行4个季度的采样调查,共计检出浮游植物8门80属316种,其中蓝藻门、绿藻门和硅藻门种类分别占总种类数的10.75%、15.22%和68.35%.水环境因子中,温度、电导率、盐度、溶解氧和叶绿素a浓度时空变化显著,总氮、总磷浓度则随着海拔降低而呈现显著升高的趋势.调查期间,黑河张掖段浮游植物密度在0.92×10⁴~116.67×10⁴ cells/L之间,从上游到下游呈现明显的递增趋势.优势种主要集中在硅藻门,包括扇形藻（Meridion sp.）、弧形峨眉藻（Ceratoneis arcus）、极小曲壳藻（Achnanthes minutissimum）、延长等片藻细弱变种（Diatoma elongatum var.tenuis）、尖针杆藻（Synedra acus）、简单舟形藻（Navicula simplex）、谷皮菱形藻（Nitzschia palea）、变异直链藻（Melosira varians）、普通等片藻（Diatoma vulgaris）、肘状针杆藻（Synedra ulna）等,此外,在河段优势种中,中下游出现蓝藻门的微囊藻（Microcystis sp.）（优势度为0.025）、绿藻门的四尾栅藻（Scenedesmus quadricauda）（优势度为0.020）、隐藻门的尖尾蓝隐藻（Chroomonas acuta）和卵形隐藻（Cryptomonas ovata）（优势度为分别为0.045和0.032）种类.4个季度Shannon-Wiener多样性指数（H''）均值分别为2.65、2.76、2.89和2.44,Pielou均匀度指数（E）均值为0.93、0.90、0.91和0.87,Margalef丰富度指数（d）均值为1.73、1.77、2.00和1.31.随着海拔的降低,浮游植物H''和d显著升高,而E变化范围相对平稳.结合水体营养盐指标、浮游植物及多样性指数等指标对水质评价,黑河张掖段水质总体呈无污染或轻度污染到轻中度污染状态,且中游污染程度加剧.RDA与Pearson相关性分析结果表明,水体氮磷营养盐、温度、海拔是影响黑河张掖段浮游植物群落结构及动态的关键因素,而在河段下游,电导率、盐度也是影响浮游植物群落结构的主要环境因子.  相似文献   

Three dimensional diagnostic study of the circulation in the South China Sea during winter 1998     

Guanghong Liao  Yaochu Yuan  Xiaohua Xu 《Journal of Oceanography》2008,64(5):803-814

On the basis of hydrographic data obtained from 28 November to 27 December, 1998, the three-dimensional structure of circulation in the South China Sea (SCS) is computed using a three-dimensional diagnostic model. The combination of sea surface height anomaly from altimeter data and numerical results provides a consistent circulation pattern for the SCS, and main circulation features can be summarized as follows: in the northern SCS there are a cold and cyclonic circulation C1 with two cores C1-1 and C1-2 northwest of Luzon and an anticyclonic eddy (W1) near Dongsha Islands. In the central SCS there is a stronger cyclonic circulation C2 with two cores C2-1 and C2-2 east of Vietnam and a weaker anticyclonic eddy W2 northwest of Palawan Island. A stronger coastal southward jet presents west of the eddy C2 and turns to the southeast in the region southwest of eddy C2-2, and it then turns to flow eastward in the region south of eddy C2-2. In the southern SCS there are a weak cyclonic eddy C3 northwest of Borneo and an anti-cyclonic circulation W3 in the subsurface layer. The net westward volume transport through section CD at 119.125°E from 18.975° to 21.725°N is about 10.3 × 10⁶ m³s⁻¹ in the layer above 400 m level. The most important dynamic mechanism generating the circulation in the SCS is a joint effect of the baroclinicity and relief (JEBAR), and the second dynamical mechanism is an interaction between the wind stress and relief (IBWSR). The strong upwelling occurs off northwest Luzon.  相似文献   

An Overview of the Semi-arid Climate and Environment Research Observatory over the Loess Plateau   总被引：19，自引：2，他引：17  

HUANG Jianping  ZHANG Wu  ZUO Jinqing  BI Jianrong  SHI Jinsen  WANG Xin  CHANG Zhoulin  HUANG Zhongwei  YANG Su  ZHANG Beidou  WANG Guoyin  FENG Guanghong  YUAN Jiuyi  ZHANG Lei  ZUO Hongchao  WANG Shigong  FU Congbin  CHOU Jifan 《大气科学进展》2008,25(6):906-921

  相似文献   

黔西南泥堡—包谷地卡林型金矿田热液矿物地球化学特征及其地质意义     

李松涛  刘建中  夏勇  王泽鹏  谢卓君  谭亲平  周光红  张兵强  谭礼金  蒙明华  郑禄林 《地质论评》2022,68(2):551-570

黔西南泥堡—包谷地卡林型金矿田以泥堡特大型金矿床为主体,兼具一系列小型金矿床和新发现的金矿点.笔者等在矿田内系统采集了与成矿密切相关的石英、方解石、萤石和辉锑矿样品,分析微量元素和稳定同位素地球化学特征,探讨成矿流体性质及来源.分析结果显示,石英、方解石和萤石整体上富集As、Sb、Li、Sr、W等元素,其中As、Sb成...  相似文献