Altitudinal shift in stable hydrogen isotopes and microbial tetraether distribution in soils from the Southern Alps,NZ: Implications for paleoclimatology and paleoaltimetry

The Southern Alps are an ideal locality for studying patterns of isotopic fractionation associated with orographic precipitation. We have evaluated whether altitudinal change is reflected in the stable hydrogen isotopic composition (δ²H) of stream water, plant stem water and leaf wax lipids (n-alkanes) from living plants and soils, as well as in soil temperature. Samples were collected along an altitudinal transect from the windward side of the Southern Alps to Lake Hawea in the rain shadow. The results indicate that δ²H values of stem water overlap with stream water, demonstrating a gradual decrease with elevation that complied with modeled Rayleigh distillation, reflecting an isotopic lapse rate of −18.0 (± 1.1, 1σ)‰/km. Leaf and soil n-alkanes shared similar δ²H values and were ²H depleted relative to stem/stream waters. The values for soil n-alkanes indicated an isotopic lapse rate of −21.8 (± 2.0, 1σ)‰/km, consistent with precipitation data and long term observations. MBT/CBT derived soil temperature values based on the relative distribution of microbial tetraether lipids were similar to midsummer temperature observations, displaying an elevational decrease rate of −5.6 (± 1.5, 1σ) °C/km, consistent with regional and global observations.The results indicate that sedimentary lipid δ²H and microbial tetraether temperature estimates captured altitudinal trends in the isotopic composition of precipitation and mean temperature and further support their application in the reconstruction of past climate and surface uplift histories. However, notable differences in isotopic composition and temperature estimates between in situ soils and those with downslope transport of material emphasize the importance of facies analysis when interpreting past systems.     

挪威块状硫化物矿床中单斜与六方磁黄铁矿的交生及其成因

矿石的镜下结构研究进一步确证，挪威加里东造山带块状硫化物矿床中的磁黄铁矿绝大部分是沉积－成岩作用的直接产物，并在其形成之后经历了多期次的变形和退火，还有一部分磁失矿是在退变质阶段形成的，或者是由变质热液形成的。这次研究中未发现由黄铁矿变质而成的磁黄铁矿     

Overview of In—Situ Biodegradation and Enhancement

Microbial degradation technologies have been developed to restore ground water quality in aquifers polluted by or-ganic contaminants effectively in recent years. However, in course of the degradation, the formation of biofilms in ground wa-ter remediation technology can be detrimental to the effectiveness of a ground water remediation project. Several alternatives are available to a remedial design engineer, such as Permeable Reactive Barriers (PRBs) and in -situ bioremediation, Hy-drogen Releasing Compounds (HRCs) barrier, Oxygen Releasing Compounds (ORCs) barrier etc. which are efficient and cost ?effective technologies. Excessive biomass formation renders a barrier ineffective in degrading the contaminants, Efforts are made to develop kinetics models which accurately determine bio - fouling and bio - film formation and to control excessive biomass formation.     

陕西天文台守时用氢原子钟

本文介绍了陕西天文台守时用氢原子钟（Ｈ２）的改进、分项误差、准确度及在国际时间局（ＢＩＰＭ）公报中取权情况．Ｈ２自１９９１年开始连续运转至今已两年多了。１９９１年３月开始每月向ＢＩＰＭ报送数据，１９９１年９月开始取权１．Ｈ２是我国唯一的一台在ＢＩＰＭ公报上取权的氢钟．     

红旗岭矿床茶尖矿区铂族元素地球化学特征及其意义

以红旗岭铜镍硫化物矿床茶尖矿区1号和9号岩体为研究对象,进行了岩石化学特征分析、微量元素分析和稀土元素（REE）分析,重点研究了其铂族元素（PGE）地球化学特征。REE分析结果表明,岩石富集轻稀土元素,且有微弱的铕负异常。PGE富集在硫化物含量高的岩石中,与硫化物含量呈正相关关系。岩石中PGE分异明显,富集Rh、Pt和Pd。推测该区的基性-超基性岩形成于硫不饱和玄武质岩浆的演化,岩浆有地壳物质混染的特征,其成矿物质来源于上地幔,主要成矿机制为深部熔离-贯入作用。     

Influence of hydrogen on Fe–Mg interdiffusion in (Mg,Fe)O and implications for Earth’s lower mantle

Interdiffusion of Fe and Mg in (Mg,Fe)O has been investigated experimentally under hydrous conditions. Single crystals of MgO in contact with (Mg_0.73Fe_0.27)O were annealed hydrothermally at 300 MPa between 1,000 and 1,250°C and using a Ni–NiO buffer. After electron microprobe analyses, the dependence of the interdiffusivity on Fe concentration was determined using a Boltzmann–Matano analysis. For a water fugacity of ∼300 MPa, the Fe–Mg interdiffusion coefficient in Fe _x Mg_1−x O with 0.01 ≤ x ≤ 0.25 can be described by with and C = −80 ± 10 kJ mol⁻¹. For x = 0.1 and at 1,000°C, Fe–Mg interdiffusion is a factor of ∼4 faster under hydrous than under anhydrous conditions. This enhanced rate of interdiffusion is attributed to an increased concentration of metal vacancies resulting from the incorporation of hydrogen. Such water-induced enhancement of kinetics may have important implications for the rheological properties of the lower mantle.

Mechanisms of hydrogen incorporation and diffusion in iron-bearing olivine

The incorporation and diffusion of hydrogen in San Carlos olivine (Fo₉₀) single crystals were studied by performing experiments under hydrothermal conditions. The experiments were carried out either at 1.5 GPa, 1,000°C for 1.5 h in a piston cylinder apparatus or at 0.2 GPa, 900°C for 1 or 20 h in a cold-seal vessel. The oxygen fugacity was buffered using Ni–NiO, and the silica activity was buffered by adding San Carlos orthopyroxene powders. Polarized Fourier transform infrared (FTIR) spectroscopy was utilized to quantify the hydroxyl distributions in the samples after the experiments. The resulting infrared spectra reproduce the features of FTIR spectra that are observed in olivine from common mantle peridotite xenoliths. The hydrogen concentration at the edges of the hydrogenated olivine crystals corresponds to concentration levels calculated from published water solubility laws. Hydrogen diffusivities were determined for the three crystallographic axes from profiles of water content as a function of position. The chemical diffusion coefficients are comparable to those previously reported for natural iron-bearing olivine. At high temperature, hydrogenation is dominated by coupled diffusion of protons and octahedrally coordinated metal vacancies where the vacancy diffusion rate limits the process. From the experimental data, we determined the following diffusion laws (diffusivity in m² s⁻¹, activation energies in kJ mol⁻¹): for diffusion along [100] and [010]; for diffusion along [001]. These diffusion rates are fast enough to modify significantly water contents within olivine grains in xenoliths ascending from the mantle.     

树轮氢、氧同位素研究进展

总结了树轮氢氧同位素的分馏原理及其时间序列和空间变化与气候变迁之间的关系。研究表明,树轮氢氧同位素组成的变异反映了源水同位素组成、温度、相对湿度和降水量的变化。同时,对今后树轮同位素的发展方向作了展望。     

Emission scenarios for a global hydrogen economy and the consequences for global air pollution

Hydrogen is named as possible energy carrier for future energy systems. However, the impact of large-scale hydrogen use on the atmosphere is uncertain. Application of hydrogen in clean fuel cells reduces emissions of air pollutants, but emissions from hydrogen production and leakages of molecular hydrogen could influence atmospheric chemistry. This paper combines a global energy system model and a global atmospheric model to explore the range of impacts of hydrogen on atmospheric chemistry. We found that emissions of molecular hydrogen may range from 0.2 up to 10% (or 25-167 Tg hydrogen/yr) for a global hydrogen energy system. The lower end of this range would in fact be equal to current emissions from fossil fuel combustion. Hydrogen energy use leads to a clear decrease in emissions of carbon monoxide, nitrogen oxides and sulphur dioxide, but large-scale hydrogen production from coal may lead to net increase in emissions of nitrous oxide and volatile organic compound. Compared to a reference scenario, this would lead to positive impacts on surface concentrations of carbon monoxide, nitrogen oxides and ozone. However, if hydrogen leakage would not be minimised it leads to an increase in methane lifetimes and a decrease in stratospheric ozone concentrations.     

用核测井孔隙度差异法解释深层天然气

随着勘探技术的进步,我国发现了许多深层天然气,它的埋藏深度大于3500m。然而,气层岩石孔隙度随着埋藏深度增加而减小,结果引起核测井读数分辨率降低。采用核测井读数解释深层天然气,识别气层的分辨率极差,有时候难以发现深层天然气。本文提出的核测井孔隙度差异法,用于解释我国某气田深层天然气,获得了令人满意的效果。