A High-K, Mantle Derived Plutonic Suite from 'Linga', near Arequipa (Peru)   总被引：2，自引：0，他引：2  

LE BEL  L.; COCHERIE  A.; BAUBRON  J. -C.; FOUILLAC  A. M.; HAWKESWORTH  C. J. 《Journal of Petrology》1985,26(1):124-148

The Linga Group consists of a suite of Cretaceous high-K calc-alkalinerocks intruded into 2?0 Ga old basement in S.E. Peru. The rocksrange in composition from gabbros, through diorites and grandioritesto granites. Microprobe, major and trace element and isotopedata suggest the suite evolved by fractional crystallization,with plagioclase as the dominant phase and with surprisinglylittle interaction with the pre-existing crust. The rocks yieldan Rb/Sr whole rock isochron of 68 ? 3 Ma with an initial Sr-isotoperatio 0.70516 ? 8, and from three Nd-isotope analyses initialNd = – 1?4 to – 2?0. ¹⁸ O increases from 5?0 permil in a gabbro to 7?0 per mil in a granite, and models arepresented which suggest that the suite evolved from parentalmagmas which had ¹⁸O = 5?8 to 6?0 per mil, 1.5 per cent K₂O,63 p.p.m. Rb, 582 p.p.m. Sr, 35 p.p.m. Ce, 0.38 p.p.m. Ta, ⁸⁷Sr/⁸⁶Sr= 0.7052, and ¹⁴³Nd/¹⁴⁴Nd = 0.51247. Trace element considerationsimply that these magmas contain contributions from incompatibleelement enriched upper mantle material and from a componentassociated with subduction. The latter is thought to reflectthe preferential mobilization of alkali and alkaline earth elementsby H₂O-rich fluids from the subducted slab, and preliminarycalculations indicate that it was responsible for {small tilde}45 per cent of the Sr and {small tilde} 80 per cent of the Kin the more primitive Linga rocks. However, the isotope datasuggest that while the fluids may be from the subducted slab,the elements in this component may also have been mobilizedfrom the overlying mantle wedge.  相似文献   

Two decades of ocean CO₂ sink and variability     

C. LE QUÉRÉ  O. AUMONT  L. BOPP  P. BOUSQUET  P. CIAIS  R. FRANCEY  M. HEIMANN  C. D. KEELING  R. F. KEELING  H. KHESHGI  P. PEYLIN  S. C. PIPER  I. C. PRENTICE  P. J. RAYNER 《Tellus. Series B, Chemical and physical meteorology》2003,55(2):649-656

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A Chemical and Multi-Isotope Study of the Western Cape Olivine Melilitite Province, South Africa: Implications for the Sources of Kimberlites and the Origin of the HIMU Signature in Africa   总被引：5，自引：3，他引：5  

JANNEY  P. E.; LE ROEX  A. P.; CARLSON  R. W.; VILJOEN  K. S. 《Journal of Petrology》2002,43(12):2339-2370

We present major and trace element and Sr–Nd–Pb–Hf–Osisotopic data for the 76–58 Ma Western Cape melilititeprovince, an age-progressive magmatic lineation in which primitiveolivine melilitite intrusives and alkali basalt lavas have beenemplaced on the southwestern margin of South Africa. The magmasrange from alkali basalts with strong HIMU isotopic and traceelement affinities on the continental shelf to melilitites withkimberlite-like incompatible element compositions and EM 1 isotopicaffinities on thick Proterozoic lithosphere (i.e. ⁸⁷Sr/⁸⁶Sr_i= 0·7029–0·7043,  相似文献   

三维激光点云数据在既有地下人防工程BIM模型重建中的应用     

苗亚哲  李胜波  邓安仲  乐观  戴作球 《测绘通报》2019,(6):100-104

BIM模型的创建是实现BIM技术应用的第一步,常见的基于CAD图纸的BIM模型创建方法存在建模效率低、空间表现不直观的缺点、本丈以某地下人防工程的B1M模型重建为例,结合=维激光扫描技术,详细阐述了基于维激光点云数据的BIM模型重建过程,主要步骤为:①利用FARO Focus3DX330获取海量点云数据;②利用FARO SCENE软件完成点云数据的配准拼接,滤波去噪.贴图输出;③按目标对象几何形状和功能特征的差异,利用Autodesk Revil分别完成线性类、构件连接类、单体目标类点云对象的B1M模型制作.研究表明,利用三维激光扫描技术可以很好地完成BIM模型的重建.而且具有建模精度高、现场还原度好的优势.  相似文献   

南海北部冬、夏季浮游群落呼吸率     

曾祥茜  郝锵  周光东  乐凤凤  刘诚刚  周文礼 《海洋学报(英文版)》2018,37(8):74-83

Plankton respiration is an important part of the carbon cycle and significantly affects the balance of autotrophic assimilation and heterotrophic production in oceanic ecosystems. In the present study, respiration rates of the euphotic zone plankton community(CR_(eu)), size fractionated chlorophyll a concentration(Chl a), bacterial abundance(BAC), and dissolved oxygen concentration(DO) were investigated during winter and summer in the northern South China Sea(n SCS). The results show that there were obvious spatial and temporal variations in CR_(eu) in the n SCS(ranging from 0.03 to 1.10 μmol/(L·h)), CR_(eu) in winter((0.53±0.27) μmol/(L·h)) was two times higher than that in summer((0.26±0.20) μmol/(L·h)), and decreased gradually from the coastal zone to the open sea. The distribution of CR_(eu) was affected by coupled physical-chemical-biological processes, driven by monsoon events. The results also show that CR_(eu) was positively correlated with Chl a, BAC, and DO, and that BAC contributed the highest CR_(eu) variability. Furthermore, the results of the stepwise multiple linear regression suggest that bacteria and phytoplankton were the dominant factors in determining CR_(eu)(R~2 = 0.82, p0.05) in the n SCS. Based on this relationship, we estimated the integrated water column respiration rate(CRint) within 100 m of the investigated area, and found that the relationship between the biomass of the plankton community and respiration may be nonlinear in the water column.  相似文献   

基于面板数据的我国海洋渔业经济的影响因素          下载免费PDF全文

乐家华  卞杰 《海洋开发与管理》2018,35(6):15-19

本研究选取海洋渔业固定资产投资额、海洋渔业劳动力数量、海洋捕捞生产率和海水养殖生产率4个变量,提出影响因素假设;选取我国沿海地区海洋渔业的面板数据,进行模型设定和数据检验。通过确定变截距固定效应的回归模型形式,对模型进行估计和分析,结果表明:海洋渔业固定资产投资额、海洋渔业劳动力数量和海水养殖生产率与海洋渔业经济呈正相关,影响度由大到小依次为劳动力因素、资本因素和生产率因素,而海洋捕捞生产率的影响基本不显著;各地区海洋渔业经济发展程度不一,且差距明显。在此基础上,提出促进我国海洋渔业经济发展的对策建议:加强专业人才集聚;提高资本投入,完善资本市场建设;提高海水养殖生产率,数量和品质兼备;推动区域一体化联动发展。  相似文献   

太湖水体散射特性及其空间分异   总被引：2，自引：0，他引：2  

孙德勇  李云梅  王桥  乐成峰  黄昌春  伍蓝 《湖泊科学》2008,20(3):389-395

利用Wetlabs公司研制的AC-S和BB9于2006年10月24目至11月2目对太湖水体的散射系数和后向散射系数进行了测量,在此基础上建立了太湖水体散射系数与后向散射系数之间的关系模型。用2种曲线函数模拟,即在蓝光波段使用S形曲线模型,在绿光和红光波段使用逆函数模型,各模型的MAPE和RMSE变化范围分别为0.027-0.156m^-1、0.005-0.050m^-1,模型整体预测精度都较高。研究发现后向散射系数与散射系数的空间分异现象明显,北部梅梁湾、湖心区、西部及西南部水域散射较强,而东太湖、胥口湾等东部水域的散射相对较弱。  相似文献   

2000—2015年夏秋季孟加拉湾湾口区涡流相互作用能量学特征     

乐洲  黄科  Venkata Subrahmanyam Mantravadi 《热带海洋学报》2020,39(2):11-14

文章主要使用全球简单海洋资料同化分析系统(Simple Ocean Data Assimilation, SODA)产出的海洋再分析数据产品和美国国家环境预报中心(National Centers for Environmental Prediction, NCEP)发布的风场资料, 通过能量学方法分析了2000—2015年夏季至秋季(6—11月)孟加拉湾涡-流相互作用特征在不同印度洋偶极子(Indian Ocean Dipole, IOD)事件发生年的表现。结果表明, 在IOD负位相年更强的西南季风背景下, 涡动能和涡势能的量值均较大, 海洋不稳定过程更多地将平均流场的能量输向涡旋场, IOD正位相年反之。另外, 研究发现孟加拉湾湾口区的涡动能在个别年份会发展出一种与气候态存在显著异常的空间分布, 即在个别年份湾口中央海域异常出现涡动能极大值。通过对出现该异常现象最显著的2010年进行个例分析, 发现当年的孟加拉湾海表风场发展出一个气旋式环流异常, 显著地改变了海洋上层环流形态, 极大地影响了平均流场与涡旋场之间的相互作用。进一步对维持涡动能平衡的各做功项进行诊断后发现, 湾口异常海域涡动能年际变化的主要影响因素为海洋内部的压强做功, 其次是正压不稳定过程和平流的做功, 海表风应力做功项贡献较小。  相似文献   

海水养殖业资源与环境的可持续发展     

宁修仁  刘诚刚  郝锵  乐凤凤 《海洋学研究》2007,25(3):75-83

概述了我国海水养殖业在快速发展过程中由于出现养殖产业规划滞后和养殖生态环境恶化而带来的若干问题。简要介绍"浙江省重点养殖海湾养殖生态和养殖容量研究"的立项背景和研究目的,鱼类、贝类和大型藻类的养殖容量研究方法以及相关的主要研究成果,展示了近海养殖生态和养殖容量的研究思路,为相关研究的进一步展开提供了一个范例。海水养殖的长远发展必须走可持续发展之路,良好的沿岸生态环境、资源与环境的和谐是支撑海水养殖业健康、持续发展的前提。总结了我国海水养殖业管理取得的进步并指出尚存在的问题。针对海水养殖业保持可持续发展的基本途径,提出了海水养殖业的规划管理和海水养殖技术改进等方面的科学建议。  相似文献   

Ozone and C2–C5 hydrocarbon observations in the marine boundary layer between 45°S and 77°S     

V. GROS†  D. MARTIN  N. POISSON  M. KANAKIDOU  B. BONSANG  F. LE GUERN  E. DEMONT 《Tellus. Series B, Chemical and physical meteorology》1998,50(5):430-448

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