海洋中铁的来源、形态和对初级生产力的限制作用

在海洋中,铁和Ｎ、Ｐ等主营养盐一样,也是一种限制浮游植物初级生产力的重要因素。由于铁是一种化学活性较高的元素,所以海水中铁的存在形态、来源及沉降会直接影响其生物可利用性。目前人们一般采用预富集／原子吸收法（ＡＡＳ）或是借助于电分析技术（如催化极谱）来测定海水中的铁。     

南丹铁陨石物态方程用于地核的研究

从南丹铁陨石的物态方程和地球的PREM模型出发,求得内外地核交界面处的物质密度为12.83-13.419/cm~3,温度为5440-5680K;地心处物质密度为13.12-13.73g/cm~3,温度为5660-5990K,推估内地核可能由铁镍合金组成.     

Relationships among dissolved organic matter,iron, and discharge in a moorland stream

Dissolved organic matter (DOM) and iron in a moorland stream were determined at 8-hour intervals over a 6-month period to examine relationships with streamflow. Regression of both solutes on discharge were positive and explained 50–70 per cent of the variance in the solute data, but better predictions were obtained in both cases when a covariate reflecting temporal variation in the relationships was introduced (explained variance 80–90 per cent). Variations in the regression of Fe on DOM were also identified, indicating differences in the complexing power of DOM for Fe and possible variations in the chemical composition of the DOM.     

Factors Controlling Sulfide Geochemistry in Sub-tropical Estuarine and Bay Sediments

The primary factors that control the concentration of total reduced (inorganic) sulfide in coastal sediments are believed to be the availability of reactive iron, dissolved sulfate and metabolizable organic carbon. We selected nine sites in shallow (<3 m), close to sub-tropical, estuaries and bays along the central Texas coast that represented a range in sediment grain size (a proxy for reactive iron), salinity (a proxy for dissolved sulfate), and total organic carbon (a proxy for metabolizable organic carbon). Based on these parameters a prediction was made of which factor was likely to control total reduced sulfide at each site and what the relative total reduced sulfide concentration was likely to be. To test the prediction, the sediments were analyzed for total reduced sulfide, acid volatile sulfide, and citrate dithionate-extractable, HCl-extractable and total Fe in the solid phase. Using solid-state gold–mercury amalgam microelectrodes and voltammetry, we determined pore water depth profiles of Fe(II) and ΣH₂S and presence or absence of FeS_(aq). At five of the nine sites the calculated degree of sufildization of citrate dithionite-reactive-iron was close to or greater than 1 indicating that rapidly reactive iron was probably the limiting factor for iron sulfide mineral formation. At one site (salinity = 0.9) dissolved Fe(II) was high, ΣH₂S was undetectable and the total reduced sulfide concentration was low indicating sulfate limitation. At the last three sites a low degree of sulfidization and modest total reduced (inorganic) sulfide concentrations appeared to be the result of a limited supply of metabolizable organic carbon. Fe(II)–S(-II) clusters (FeS_(aq)) were undetectable in 10 out of 12 bay sediment profiles where ΣH₂S was close to or below detection limits, but was observed in all other porewater profiles. Acid volatile sulfide, but not total reduced sulfide, was well correlated with total organic carbon and ranged from being undetectable in some cores to representing a major portion of total reduced sulfide in other cores. Although predicted controls on total reduced sulfide were good for very low salinity water or sandy sediments, they were only right about half the time for the other sediments. The likely reasons for the wrong predictions are the poor correlation of total organic carbon with grain size and differing fractions of metabolizable organic carbon in different sedimentary environments. Differences in sediment accumulation rates may also play a role, but these are difficult to determine in this region where hurricanes often resuspend and move sediments. This study demonstrates the need to examine more complex and often difficult to determine parameters in anoxic “normal marine” sediments if we are to understand what controls the concentration and distribution of sulfides.     

基于空间统计学的空间数据窗口大小的确定

提出基于空间统计学的方法来确定空间数据窗口大小,实例证明是可行的。同时提出了对海底照片成像不均匀光照进行纠正的思路和方法，该方法简单有效，效果较理想。     

蓝藻聚铁作用的模拟实验

实验模拟前寒武纪大气的高二氧化碳分压(P_CO2),低氧浓度条件下,加入较低浓度(6μg/g)铁的Zarronk培养液培养蓝藻Spirulina platensis,观察铁的沉淀与凝聚。藻在生长过程中不断改变环境的离子平衡系统以及pH,Eh等,造成铁的氧化、还原、络合和Fe³⁺沉淀。实验组与未加蓝藻的对照组有显著差别。实验证实藻在聚铁和铁矿形成中起重要作用。     

遥感图像中云层遮挡影响消除方法研究述评

 综合评述了目前用于消除遥感图像云层遮挡影响方法的原理、应用现状及处理过程中存在的问题，并在同一实验区比较了同态滤波和Kriging插值等方法的处理效果，结果表明，Kriging插值处理具有一定的优越性。     

Reappraisal of the structure of the Western Iron Ore Group, Singhbhum craton, eastern India: Implications for the exploration of BIF-hosted iron ore deposits

The middle to late Archean Iron Ore Group rocks occurring along the western margin (the Western Iron Ore basin) of the Singhbhum Granite massif in the Singhbhum craton were deformed during Iron Ore orogeny and are disposed in a horseshoe-shaped synclinal structure in the eastern part of the Indian shield. The Western Iron Ore basin hosts almost all the major high-grade iron ore deposits of eastern India. Contrary to the established view, present analysis emphasizes that the horseshoe fold in reality is a synclinorium consisting of a syncline–anticline fold pair which were later cross-folded along an east–west axis.

Structural analysis in the eastern anticline of the ‘horseshoe synclinorium’ suggests that the BIF hosting the high-grade iron ore bodies are disposed in three linear NNE–SSW trending belts, each showing an open synclinal geometry. Later cross folding produced development of widespread dome and basin pattern at the sub-horizontal hinge zones of these synclinal fold belts. The major iron ore deposits in the eastern anticline at the present level of erosion are preferentially localized within shallow elongated basinal structures only. The axis of the adjoining western syncline was similarly uplifted as partial culminations where cross-folded against E–W anticlinal axes. But here, the BIF-iron ore bodies are preferentially localized within elongated domal structures in contrast to the basinal sites in the adjacent eastern anticline. Such an inference based on structural analysis could probably be utilized as a potential tool for all future explorations, reserve estimation and recovery of the iron ore deposits in the terrain.     

Solubility of FeO in (Mg,Fe)SiO3 perovskite and the post-perovskite phase transition

Phase relations in Mg_0.5Fe_0.5SiO₃ and Mg_0.25Fe_0.75SiO₃ were investigated in a pressure range from 72 to 123 GPa on the basis of synchrotron X-ray diffraction measurements in situ at high-pressure and -temperature in a laser-heated diamond-anvil cell (LHDAC). Results demonstrate that Mg_0.5Fe_0.5SiO₃ perovskite is formed as a single phase at 85–108 GPa and 1800–2330 K, indicating a high solubility of FeO in (Mg,Fe)SiO₃ perovskite at high pressures. Post-perovskite appears coexisting with perovskite in Mg_0.5Fe_0.5SiO₃ above 106 GPa at 1410 K, the condition very close to the post-perovskite phase transition boundary in pure MgSiO₃. The coexistence of perovskite and post-perovskite was observed to 123 GPa. In addition, post-perovskite was formed coexisting with perovskite also in Mg_0.25Fe_0.75SiO₃ bulk composition at 106–123 GPa. In contrast to earlier experimental and theoretical studies, these results show that incorporation of FeO stabilizes perovskite at higher pressures. This could be due to a larger ionic radius of Fe²⁺ ion, which is incompatible with a small Mg²⁺ site in the post-perovskite phase.