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831.
Yoko-Dovyren层状纯橄岩-橄长岩-辉长岩地块位于西伯利亚克拉通南部的一处褶皱构造框架中(俄罗斯贝加尔湖地区北部)。该地块的结构在其厚度最大的中部得到了着重研究。剖面底部主体成分为斜长橄榄岩,并依据内部的堆晶成分变化从下往上可分为五个主要的地层序列:纯橄岩→橄长岩→橄榄辉长岩→橄榄辉长苏长岩→石英辉长苏长岩以及含易变辉石的辉长岩。该地块的矿化包括铜-镍矿化、低硫型富铂族元素(PGE)矿化以及铬铁矿化等。另外,该地块也含多种非金属矿物原材料,如硼矿化、透辉石、各种镁质硅酸盐岩等。它们也包括纯橄岩、异剥橄榄岩和橄长岩,并以较高的品质产出,有望采掘加工成为建筑材料(水泥、混凝土、沥青混凝土和建筑陶瓷)。综合利用矿物原材料可增加矿床价值,并有助于建设环保型采矿工作体系。 相似文献
832.
渐新世代表地球一个早期的“冰室”期,是地球气候演化和生物演替过程中一段特殊的时期。渐新世植物化石的碳同位素可为研究该时期的古气候提供依据。对广西渐新世宁明组三种植物及其最近现生亲缘种的碳同位素进行分析,化石种Buxus ningmingensis,Chuniophoenix slenderifolia和Cephalotaxus ningmingensis的碳同位素组成(δ13C)分别为-29.0‰,-28.3‰,-28.0‰;碳同位素分馏(Δ13C)分别为23.48‰,22.74‰,22.43‰;叶内细胞间和外界大气的CO2分压比(C植物/C空气)分别为0.84,0.81,0.80;水分利用效率(WUE)分别为42.63μmol CO2/mol H2O,51.56μmol CO2/mol H2O,55.38 μmol CO2/mol H2O。其对应的最近现生亲缘种(NLRs)的δ13C分别为-27.9‰,-29.7‰,-28.8‰;Δ13C分别为20.47‰,22.36‰,21.42‰;C植物/C空气分别为0.71,0.79,0.75;WUE分别为72.22 μmol CO2/mol H2O,51.28μmol CO2/mol H2O,61.76 μmol CO2/mol H2O。化石种δ13C值均落在现代C3植物相应的数值范围内,其Δ13C和C植物/C空气均高于相应的NLRs数值;而Buxus ningmingensis和Cephalotaxus ningmingensis的WUE低于相应的NLRs数值;其中Chuniophoenix slenderifolia的WUE稍高于相应的最近现生亲缘种C. hainanensis,推测可能与其NLR标本的母本植物生长在水源充足、空气潮湿的湖溪边湿地环境有关。基于Δ13C、C植物/C空气和WUE结果,推测化石种可能生活在一种比现在更为温暖湿润的气候环境中;化石种及同层位化石的古气候重建支持了当前古气候分析结果。 相似文献
833.
Weerakoon S. B. 《山地科学学报》2005,2(3):225-232
A distributed hillslope model is presented for the computation of seasonal sediment loads flowing into the rain-fed irrigation reservoirs (tanks) from the mountainous catchments in Sri Lanka. The model is based on the subdivision of the catchment into hillslopes and application of a sediment transport capacity equation at hillslope scale and computation of sediment loads transported to the tanks. Coarse and fine sediment loads due to hourly excess rainfall during a season are separately estimated. The model depends on fewer parameters and can be easily calibrated for a tank. The model calibration only requires measurements of coarse and fine sediment loads transported into the tank due to several rainfalls of different intensities from a representative subcatchment of the tank. Coarse sediment loads are measured by using a sediment trap installed across an ephemeral stream draining the subcatchment. Fine sediment loads are obtained by measuring the discharge and accompanied sediment concentrations over the sediment trap. The model is calibrated, verified and applied for an irrigation tank in Sri Lanka to estimate the seasonal sedimentation loads. 相似文献
834.
近几年来的研究发现,当存在较强的构造活动时,古地理特征变化将会加快,而常规方法很难对这一构造活动过程中的古地理和古地貌进行有效的恢复和研究。Basin and Landscape Dynamics(Badlands)软件正是基于前人的研究工作而开发的一款数值模拟软件,用于模拟各种空间和时间尺度的地貌演化。它可用于研究地表演化过程、预测侵蚀和沉积速率并评估沉积物通量,从而实现对古地理和古地貌进行更为精细化的研究。笔者介绍了Badlands软件的基本原理和方法,并将此方法应用于东海陆架盆地南部中生代地貌及地质演化过程的研究: 首先利用研究区域内现有的地震剖面、测井、平衡剖面等资料获得中生代早期的古地形;再通过恢复的古地形构建数值模型,并加载降雨量、岩石侵蚀性、海平面变化、动力地形调整和地壳弹性层厚度等相关参数进行模拟研究,以分析强烈的构造运动对盆地地貌演化的影响;最后对比模拟结果与已知的中生代的地貌特征和沉积分布,并据此进一步分析中生代盆地演化过程中的沉积物分布规律以及三维古地理和古地貌演化特征。该方法可以为沉积盆地充填过程分析和能源矿产勘探提供有益的思路。 相似文献
835.
楚科奇和西伯利亚陆架颗粒有机物的来源:碳、氮同位素的线索 总被引:2,自引:1,他引:1
The stable isotopic composition(δ~(13)C and δ~(15)N) and carbon/nitrogen ratio(C/N) of particulate organic matter(POM) in the Chukchi and East Siberian shelves from July to September, 2016 were measured to evaluate the spatial variability and origin of POM. The δ~(13)C_(POC) values were in the range of -29.5‰ to-17.5‰ with an average of -25.9‰±2.0‰, and the δ~(15)N_(PN) values ranged from 3.9‰ to 13.1‰ with an average of 8.0‰±1.6‰. The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf, while the δ~(13)C and δ~(15)N values were just the opposite. Abnormally low C/N ratios(4), low δ~(13)C_(POC)(almost-28‰) and high δ~(15)N_(PN)(10‰) values were observed in the Wrangel Island polynya, which was attributed to the early bloom of small phytoplankton. The contributions of terrestrial POM, bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model. The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward, indicating the influence of Russian rivers. The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward, suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf. The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery. A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed, indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM, the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves. 相似文献
836.
S.D.Puntsukova 《东北亚地学研究》2009,(4):194-199
The author studied the issues of the present-day status of forest resources and forest management of the Selenge River Basin on the transboundary territory of the Buryat Republic and Mongolia. It is necessary to establish a good policy for wood cutting of the main and secondary use and reforestation. 相似文献
837.
Compliant offshore structures such as spars, tension leg platforms (TLPs) and semi-submersibles have been dramatically improved in recent years due to their capability for deep water operation. Waves are the most important environmental phenomenon affecting these offshore structures. Estimation of wave forces is vital in offshore structure design. For large compliant offshore plat-forms, Morrison's equation is not valid anymore and usually diffraction theory is used. In this research, by using the finite difference method, a detailed analysis of the first-order diffraction of monochromatic waves on a large cylinder as a structural element is per-formed to solve the radiation and diffraction potentials. The results showed that the developed model is a reliable tool to estimate the wave forces and hydrodynamic coefficients on large structure elements when wave diffraction and radiation are considered. 相似文献
838.
遥感和GIS技术应用于伊拉克南部Basrah省土地利用/覆盖变化及城市扩张研究(英文) 总被引:2,自引:0,他引:2
In recent years, land use/cover dynamic change has become a key subject that needs to be dealt with in the study of global
environmental change. In this paper, remote sensing and geographic information systems (GIS) are integrated to monitor, map,
and quantify the land use/cover change in the southern part of Iraq (Basrah Province was taken as a case) by using a 1:250
000 mapping scale. Remote sensing and GIS software were used to classify Landsat TM in 1990 and Landsat ETM+ in 2003 imagery
into five land use and land cover (LULC) classes: vegetation, sand, urban area, unused land, and water bodies. Supervised
classification and normalized difference build-up index (NDBI) were used respectively to retrieve its urban boundary. An accuracy
assessment was performed on the 2003 LULC map to determine the reliability of the map. Finally, GIS software was used to quantify
and illustrate the various LULC conversions that took place over the 13-year span of time. Results showed that the urban area
had increased by the rate of 1.2% per year, with area expansion from 3 299.1 km2 in 1990 to 3 794.9 km2 in 2003. Large vegetation area in the north and southeast were converted into urban construction land. The land use/cover
changes of Basrah Province were mainly caused by rapid development of the urban economy and population immigration from the
countryside. In addition, the former government policy of “returning farmland to transportation and huge expansion in military
camps” was the major driving force for vegetation land change. The paper concludes that remote sensing and GIS can be used
to create LULC maps. It also notes that the maps generated can be used to delineate the changes that take place over time.
Supported by the Al-Basrah University, Iraq, the Geo-information Science and Technology Program (No. IRT 0438)China). 相似文献
839.
The assessment of vitellogenin as a biomarker of exposure to estrogenic compounds in two Australian perciformes 总被引:1,自引:0,他引:1
Vitellogenin (Vtg) is a yolk protein precursor that has been identified as a sensitive biomarker for exposure to estrogenic compounds. We evaluated specific monoclonal and polyclonal antibodies for reactivity with plasma Vtg from two Australian Perciformes, the tropical barramundi (Lates calcarifer) and the temperate black bream (Acanthopagrus butcheri). Blood plasma from 17beta-estradiol exposed (E2) male barramundi (20 mg kg(-1)) and male black bream (2.5-5.0 mg kg(-1)) were sent to Biosense Laboratories (Norway) for cross-reactivity testing using their extensive anti-Vtg antibody selection. Indirect ELISA results determined barramundi plasma displayed the highest binding affinities to ND-3G2 (monoclonal-Mab) and PO-1 (polyclonal-Pab). Black bream was most cross-reactive with ND-1C8 (Mab) and PO-2 (Pab). Next, plasma was assessed for Vtg induction in E2-dosed (5 mg kg(-1)), hatchery-reared barramundi and black bream versus a non-injected control group. Vtg production was assessed by Western blot and indirect ELISA using ND-3G2 and ND-1C8 Mabs, respectively. A prominent band was identified in the range of 100-200 kDa for all female black bream and for all E2-treated barramundi and black bream males, which was confirmed as Vtg by Western blot. Indirect ELISA results for barramundi demonstrated highly significant differences in E2-dosed fish as compared to control fish (Student t, P<0.001). E2 male black bream were significantly different than control males (Student t, P<0.001) and control and E2 females displayed highly significant differences (Student t, P<0.001). These results indicate that exposure to 17beta-estradiol induces significant Vtg production in males of the two Australian Perciformes, with potential use as a biomarker for exposure to estrogenic compounds. 相似文献
840.
Tokumoto T Ishikawa K Furusawa T Ii S Hachisuka K Tokumoto M Tsai HJ Uchida S Maezawa A 《Marine environmental research》2008,66(3):372-377
Sonolysis and photolysis often exhibit synergistic effects in the degradation of organic molecules. An assay of fish oocyte maturation provides an appropriate experimental system to investigate the hormonal activities of chemical agents. Oocyte maturation in fish is triggered by maturation-inducing hormone (MIH), which acts on receptors on the oocyte surface. A synthetic estrogen, diethylstilbestrol (DES), possesses inducing activity of fish oocyte maturation, and a widely used biocide, pentachlorophenol (PCP), exhibits a potent inhibitory effect on fish oocyte maturation. In this study, the effects of the combined treatment by sonolysis with photolysis (sonophotocatalysis) to diminish the hormonal activity of DES and the maturation preventing activity of PCP was examined. By sonophotocatalysis, hormonal activity of DES was completely lost within 30min and the inhibiting activity of PCP was lost within 120min. These results demonstrated that sonophotocatalysis is effective for diminishing the endocrine-disrupting activity of chemical agents. 相似文献