星载微波SSM/Ⅰ遥感在中国东北华北农田的辐射特征分析

国家遥感应用工程技术研究中心ＮａｔｉｏｎａｌＥｎｇｉｎｅｅｒｉｎｇＲｅｓｅａｒｃｈＣｅｎｔｅｒｆｏｒＧｅｏｍａｔｉｃｓ（ＮＣＧ）国家遥感应用工程技术研究中心于１９９６年１２月２５日由国家科委正式批准组建（国科发计字［１９９６］６０３号文件）。中国科学...     

星载微波SSM/Ⅰ遥感在中国东北华北农田的辐射特征分析

本文研究了星载微波ＳＳＭ／Ⅰ１９９６年在中国东北华北平原农田上７个通道辐射亮度温度（ＴＢ）的遥感数据,提出用几个通道ＴＢ组合的散射指数和极化指数来分析中国平原地区农田的微波辐射特征,及其随生长季节的时间性变化。星载ＳＳＭ／Ⅰ数据可以监视农作物的生长和平原地区地面湿度的变化。本文还给出了大气和农作物地表矢量辐射传输的数值模拟结果。     

基于岭估计的SPOT影像外方位元素的解算方法

后方交会法解求 SPOT卫星影像的外方位元素时 ,其法方程系数矩阵经常产生很严重的病态 ,若用最小二乘法估计 ,参数解将明显偏离真值 ,甚至无法解得外方位元素。本文中提出了用最小二乘岭估计的方法解求外方位元素 ,实验证明这是非常有效的。     

西秦岭北带泥盆纪Nereites遗迹相及其环境分析

西秦岭北带泥盆系舒家坝组下一中上部的巨厚陆源碎屑岩系中含有极丰富的遗迹化石,它们可为解释该组沉积环境提供重要信息:（1）由大量典型深水遗迹化石组成的Nereites遗迹相,可与世界各地浊积岩系和复理石相中的Nereites遗迹相进行对比,该遗迹相主要发育在浊流沉积区直至深海平原,其沉积水深最大可超过2000m;（2）舒家坝组的遗迹群落中,除大量属深水型分子外,还见有典型的浅水分子,两种水深性质不同的遗迹组合共生在一个沉积剖面,正是浊积岩系和复理石相才具有的独特分布特征;（3）根据沉积层序和遗迹组合的对比确认舒家坝组不存在风暴岩。     

凡口铅锌矿床海底热泉喷溢成矿的物理化学环境

凡口铅锌矿是发育于碳酸盐岩建造中的海底喷溢沉积矿床 ,以“一大二富三集中”的特点和典型的地质地球化学特征吸引着中外矿床地质工作者。叠层状矿体发育于同沉积断裂的旁侧 ,矿层与灰岩呈沉积接触关系。矿石具沉积碎屑组构 ,黄铁矿、闪锌矿具外生特征。稀土元素组成和硫同位素组成反映矿床与同生作用有关。铅同位素组成具有壳源和下地壳来源铅的特征。矿区主要矿层经历海底热泉喷溢沉积—成岩的演化     

Migration and dispersion of trace elements in the rock–soil–plant system in areas underlain by black shales and slates of the Okchon Zone, Korea

The Okchon black shale in Korea provides a typical example of natural geological materials enriched with potentially toxic elements. The Chung-Joo, Duk-Pyung, Geum-Kwan, I-Won, Bo-Eun and Chu-Bu areas are underlain by these black shales and slates of the Guryongsan Formation or the Changri Formation, which are parts of the Okchon Group in the central part of the southern Korean Peninsula. In order to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock–soil–plant system, environmental geochemical surveys were undertaken in the above six study areas in the Okchon Zone. After appropriate preparation, rock and soil samples were analyzed for potentially toxic elements by instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES), and plant samples by atomic absorption spectrometry (AAS). In particular, Ba, Cd, Mo, V and U in Okchon black shales are highly enriched, and their mean concentrations are significantly higher than those in black slates. These elements are geochemically associated, and might be enriched simultaneously. The highest mean concentrations of 42.0 μg g⁻¹ As, 2100 μg g⁻¹ Ba, 10.9 μg g⁻¹ Cd, 213 μg g⁻¹ Mo, 83 μg g⁻¹ U, 938 μg g⁻¹ V and 394 μg g⁻¹ Zn are found in black shales from the Duk-Pyung area. Mean concentrations of As, Mo and U in soils overlying black shales occurring in the Duk-Pyung area (30 μg g⁻¹ As, 24 μg g⁻¹ Mo and 50 μg g⁻¹ U) and Chu-Bu area (39 μg g⁻¹ As, 15 μg g⁻¹ Mo and 27 μg g⁻¹ U) are higher than the permissible level. Enrichment index values of the six study areas decrease in the order of Duk-Pyung > Chu-Bu > Bo-Eun > Chung-Joo > Geum-Kwan = I-Won areas. Relationships between trace element concentrations in soils and plants are significantly correlated, and the biological absorption coefficients (BAC) in plants are in the order of Cd > Zn = Cu > Pb, which suggests that Cd is more bioavailable to plants than the other elements. Cadmium concentrations in plant species decrease in the order of chinese cabbage > red pepper > soybean = sesame > rice stalk > corn > rice grain. From the result of sequential extraction analysis of soils, relatively high proportions of Cu, Pb and Zn are present as residual fractions, and that of Cd as non-residual fractions. Cadmium occurs predominantly as exchangeable/water-acid soluble phase in soils, and this is in agreement with the findings of high Cd concentrations in plants.     

元素地球化学场及其地学意义

有关岩浆花岗岩成因的原地重熔说,揭示了各种化学元素在内生过程中的迁移规律。据此并结合元素在周期表中的位置,得出了元素地球化学场的概念,元素地球化学场不但总结了元素在原地重熔过程中的聚散趋势,而且揭示了元素自身组构与其空间分布规律的关系,展示出三个不同层次的地质断面,即花岗岩体上部和顶部盖层断面,大陆地壳断面及地球球体断面。     

亚南极冰川雪冰内MSA的季节变化(英)

Methanesulphonate was investigated as a potential contributor to the sulphur budget based on the analysis on Antarctic snow/ice from Coffins Ice Cap, King George Island (62°10' S, 58°50,W). The anion was found to be present at a mean concentration of 0. 17 μeq. L-1 with a maximum of 0.73 μeq. L-1. A distinct seasonal variation exists in the top 10 m of the core, equivalent to more than two years of deposition. Dating resulted from δ18O profile suggests that the principal peaks of methanesulphonate are associated with snow deposited in autumn and secondary peaks in spring. The seasonal patterns of methanesulphonate in the subantarctic snow displays a phase difference from that observed in marine air from low and middle latitudes.     

Mineral magnetic and physical properties of surficial sediments and onshore samples from the southern basin of Lake Baikal, Siberia

Results of lithostratigraphic and mineral magnetic analysis of two surficial sediment cores (21 cm and 45 cm in length) collected from the Southern basin of Lake Baikal at a water depth of 1390 m, are presented. The sediments have been measured for a wide range of mineral magnetic parameters in order to assess their value in the identification of turbidite layers. Particle size and geochemical data are also presented and these explain some of the down core variations in magnetic mineralogy. It is suggested that changes in the particle size frequency distributions down core may be related to fossil diatom shells. One of the cores has been dated using ²¹⁰Pb. The sediment cores were cross-correlated using low frequency magnetic susceptibility (f) and these cores can also be correlated with a nearby core collected earlier in 1992. Changes in the magnetic parameters of lf, IRMs and HIRM₂₁₀ suggest that there are significant changes in the concentration of ferrimagnetic minerals in the sediment cores, indicating changing sediment sources and/or increasing concentrations of spheroidal carbonaceous particles and the dissolution of minerals through reduction below the oxidised layer within the sediment core.     

Accelerator mass spectrometry radiocarbon dating of 1994 Lake Winnipeg cores

Conventional radiocarbon dating of Lake Winnipeg core samples has produced erroneously old ages due to the incorporation of pre-Quaternary carbon derived from carbonaceous rocks, soils and sediments in the watershed, as well as a hard-water effect resulting from leaching of calcareous rocks and soils. To circumvent these problems and develop a reliable chronology for the Lake Winnipeg core series, a total of 64 samples from the Lake Winnipeg core series were processed to isolate well preserved macrofossils suitable for Accelerator Mass Spectrometry (AMS) radiocarbon dating. Here we report six radiocarbon ages derived from plant macrofossils and ostracodes, and reconstruct aspects of the depositional environment of each sample based on the associated macrofossil assemblage.