Nd, Sr and O Isotopic Study on Spilite-Keratophyre in Xiqiu,,Zhejiang Province, China

Nd, Sr and O isotopic study on the spilite-keratophyre sequence in Xiqiu shows that its ∈_(Nd) values are inthe range of 4.02-5.26, and its ∈_(Sr) values, +1.4-2.6. According to the points of these data in the ∈_(Nd)-T,∈_(Sr)-T and ∈_(Nd)-∈_(Sr) diagrams, the spilite-keratophyre is interpreted as being slightly contaminated by crustalmaterials. Its δ~(18)O values are 3.9-5.0‰. The depletion of ~(18)O in the rocks resulted from the influence ofseawater hydrothermal alteration during or soon after the rock formation. Based on the isotopic characteristicsand available geochemical data, it is believed that the spilite-keratophyre was formed in the well-developedisland-arc environment during the Late Proterozoic subduction of the palaeo-Pacific plate beneath thesoutheastern margin of the Yangtze massif.     

黄铁矿型结构的晶体化学

本文根据特征离子坐标变化的特点，对黄铁矿型结构微变规律性进行了讨论，作了一些规律图，总结出：成分的变化控制着ｕ值的变化，ｕ值的变化影响着晶体结构微变化。ｕ值发生变化，ＭＸ６反三方柱的顶面和底面中３轴相向或相背移动，ｕ值增加愈接近正八面体，ｕ值发生变化，Ｘ（Ｍ３Ｘ）三方锥底面的方位不变，但锥顶（Ｘ７）和锥体内的（Ｘ１）的坐标要变化，它们会沿着锥的中轴线相向或相背移动，形成扁平型的三方锥，最后得出：当     

河南商城—固始地区石炭系沉积环境及其构造意义

根据沉积相分析,同时综合分析区域地质资料,笔者提出河南商城－固始地区石炭系及安徽金寨地区梅山群为典型前陆磨拉石含煤建造,其沉积相主要为滨海、潮坪、泻湖、局限台地及砾质辫状河－冲积扇相,代表了统一的石炭纪一二叠纪合肥弧后前陆盆地的南部边缘相,说明大别地块（北大别弧）于早古生代晚期－晚古生代早期即与华北板块碰扪结成一体。     

210Pb and 7Be as Tracers for Aerosol Transfers at Center Guizhou，China：Ⅰ．The Explanation by Weekly Interval

It′s essential to measure air concentrations and depositional fluxes of environmental radionuclides in different regions for modeling global contamination transfer and validation, tracing deposition process and dating, referencing watershed erosion trace and assessing natural radiation of ecosystem. This study introduces the research background and methods and explains weekly variations of ²¹⁰Pb and ⁷Be concentrations in surface air and precipitation at Mt. Guanfeng/Guiyang since 2001. The results indicate that ²¹⁰Pb and ⁷Be concentrations in surface air fluctuate periodically at 2~6 week interval because of the meteorological condition changes. The annual trend in ²¹⁰Pb air concentration is overall influenced by air temperature variation and periodical rainfall. ⁷Be air concentration varies up and down regualarly. The synchronization of low concentrations for both ²¹⁰Pb and ⁷Be in surface air and high ratio (²¹⁰Pb/⁷Be ≥ 0.8) indicate oceanic poor ²¹⁰Pb-⁷Be air mass invasion. The synchronization of high concentrations of ²¹⁰Pb and ⁷Be in surface air and low ratio (²¹⁰Pb/⁷Be ≤ 0.7) implies rich ⁷Be air mass invasion from altostratus atmosphere. Weekly concentrations of ²¹⁰Pb and ⁷Be in precipitation and the K_d coefficients are high in late Autumn to Spring, and low in late Spring to Autumn. Although ²¹⁰Pb and ⁷Be concentrations vary seasonally, their weekly concentrations in precipitation increase with that of air concentration. The ²¹⁰Pb and ⁷Be weekly concentrations for seasonal division is about 0.2 Bq/L and 1 Bq/L, respectively. However, the K_d coefficient decreases when ²¹⁰Pb and ⁷Be air concentrations increase. Deposition of ²¹⁰Pb and ⁷Be with precipitation mainly take place in Spring and Summer; The weekly fallout of ²¹⁰Pb and ⁷Be increases with increasing precipitation; the increase of ⁷Be is triple of that of ²¹⁰Pb and 2.5 when precipitation nears to zero. The weekly-high fallout of ²¹⁰Pb and ⁷Be with precipitation corresponds with the dramatic decrease of their air concentrations within or vicinal weeks. The ratio of ²¹⁰Pb to ⁷Be in rainfall is overall ≤ 0.5 and varies synchronously with the ratio in surface air, indicating that the two radionuclides are cleaned by precipitation from air at close speed. In the extreme freezing disaster in 2008, both ²¹⁰Pb and ⁷Be air concentrations were low and coupling with coexist of low concentration of aerosol and high nuclides activities. Weekly concentration of ⁷Be in surface air at Mt. Guanfeng demonstrates the anticipated concentration level in the low-latitude and high-elevation region; the short-term fluctuations of ⁷Be concentration indicated the hysteresis was influcenced by the strong air current submersion and the low-elevation air mass rising differently at Mt. Guanfeng and Mt. Waliguan.      

Petrology, geochemistry and isotopic ages of eclogites from the Dulan UHPM Terrane, the North Qaidam, NW China

The Dulan eclogite–gneiss region is located in the eastern part of the North Qaidam eclogite belt, NW China. Widespread evidence demonstrates that this region is a typical ultrahigh-pressure (UHP) metamorphic terrane. Eclogites occur as lenses or layers in both granitic and pelitic gneisses. Two distinguished sub-belts can be recognized and differ in mineralogy, petrology and geochemistry. The North Dulan Belt (NDB) has tholeiitic protoliths with high TiO₂ and lower Al₂O₃ and MgO contents. REE patterns and trace element contents resemble those of N-type and E-type MORB. In contrast, eclogites in the South Dulan Belt (SDB) are of island arc protoliths with low TiO₂, high Al₂O₃ and show LREE-enriched and HFSE-depleted patterns. Sm–Nd isotope analyses give isochron ages of 458–497 Ma for eclogite-facies metamorphism for the two sub-belts. The ages are similar to those of Yuka and Altun eclogites in the western extension of the North Qaidam-Altun eclogite belt. The Dulan UHP metamorphic terrane, together with several other recently recognized eclogite-bearing terrenes within the North Qaidam-Altun HP-UHP belt, constitute the key to the understanding of the tectonic evolution of the northern Tibetan Plateau. The entire UHP belt extends for more than 1000 km from the Dulan UHP terrane in the southeast to the Altun eclogite–gneiss terrane in the west. This super-belt marks an early Paleozoic continental collision zone between the Qaidam Massif and the Qilian Massif.     

Seismic Sequence in Carbonate Rocks By Vibrational Liquefaction1

Abstract On the basis of the records of strong seismic events taking place in soft carbonate sediments, a new seismic sequence system of vibrational liquefaction is established, which consists of a series of units, such as escaped structure of micrite veins and liquefied deformation formed in the period of seismic liquefaction, land subsidence structure after liquefaction, tsunamic hummocky and turbidite produced by seismic events, This sequence is a generalization and summation of field observation in vast areas, which shows the whole process of a strong seismic event and provides an unified theoretical explanation. The pattern of the seismic sequence by vibrational liquefaction provides one of correlation standards for geologists in the field to discriminate events in carbonate sequences. Based on the pattern of seismic sequence, the authors first advance a new conception of the Palaeo - Tanlu (Tancheng - Lujiang) Zone and discuss primarily its geological significations.     

Water–rock interaction during the process of steam stimulation exploitation of viscous crude oil in Liaohe Shuguang Oil Field, Liaoning, China

In the process of steam stimulation exploitation of viscous crude oil, the injected water, at high temperature and under high pressure, reacts intensively with the host rock. This kind of water–rock interaction in Liaohe Shuguang Oil Field was studied on the basis of analysis of water composition changes, laboratory experiments, mineral saturation indices analysis, and mass balance calculation. Compared with the injected water, the changes of the composition of discharged water are mainly the distinct decrease of pH, Na⁺, SiO₂ and Cl⁻, as well as the increase of K⁺, Ca²⁺, Mg²⁺, SO ₄ ²⁻ and HCO ₃ ⁻ . Laboratory experiments under field conditions showed: the dissolution sequence of minerals quantitatively is quartz>potassium feldspar>albite, and the main change of clay minerals is the conversion of kaolinite to analcime. Mass balance calculation indicated during the process of steam stimulation, large quantities of analcime are precipitated with the dissolution of large amounts of quartz, kaolinite, potassium feldspar, and CO₂. These results correlated very well with the experimental results. The calculated results of Liaohe Shuguang Oil Field showed that during the steam stimulation for viscous crude oil, the amounts of minerals dissolved (precipitated) are huge. To control the clogging of pore spaces of oil reservoirs, increased study of water–rock interaction is needed.     

鲁西新泰孟家屯2.7Ga变质沉积岩与黑云斜长片麻岩锆石Hf同位素特征

对出露于山东新泰孟家屯2.7Ga的孟家屯岩组中石榴石石英岩(M08)、含十字石石榴石黑云母石英片岩(D242-Y2)和黑云斜长片麻岩(M03)(TTG质片麻岩)进行锆石Lu-Hf同位素分析。石榴石石英岩锆石核部176Lu/177Hf、176Hf/177Hf变化范围为0.001730～0.002546、0.281249～0.281360,锆石变质边部176Lu/177Hf、176Hf/177Hf变化范围为0.000123～0.002070、0.281241～0.281318;含十字石石榴石黑云母石英片岩锆石核部176Lu/177Hf、176Hf/177Hf变化范围为0.001334～0.002169、0.281226～0.281324,锆石变质边部176Lu/177Hf、176Hf/177Hf变化范围为0.000445～0.001375、0.281227～0.281309;黑云斜长片麻岩锆石176Lu/177Hf、176Hf/177Hf变化范围为0.000315～0.000847、0.281186～0.281265。孟家屯岩组石榴石英岩、含十字石石榴石黑去母石英片岩中碎屑(岩浆)锆石和黑云斜长片麻岩中岩浆锆石的εHf(t)分别为3.75～7.26、2.31～7.26和3.21～6.27,同时TDM1与其U-Pb年龄非常接近,表明它们起源于新生地壳的部分熔融。结合区域研究资料认为,2.7Ga是鲁西重要的一期构造岩浆热事件,也可能是华北克拉通重要的构造岩浆活动时期。变质沉积岩中许多变质增生锆石相对于核部岩浆锆石低176Lu/177Hf、高176Hf/177Hf,显示变质作用过程中石榴石的存在对锆石的Lu-Hf同位素体系有很大影响。     

A geochemical survey of trace elements in agricultural and non-agricultural topsoil in Dexing area,China

In China, soil pollution is very serious, which has jeopardized the ecology, food safety, the people's health, and even the sustainable development of agriculture. In order to investigate the soil pollution situation, a total of 874 agricultural and non-agricultural topsoil samples were collected from Dexing area, northeast of Jiangxi Province, China. The total elemental concentrations of 17 elements (As, Hg, Mo, Cd, Cr, Zn, Cu, Mn, Ti, Pb, Fe, Ca, K, Si, Al, Mg, and Na) were determined. The geochemical background and threshold was predicted with the method of the median ± median absolute deviation (MAD). The agricultural soil median concentration of trace elements was similar to that of the non-agricultural soil. In contrast to Jiangxi soil background of trace elements, the geochemical background of the study area was obviously higher. The maps of the pollution indices for As, Cd, Cr, Cu, Hg, Mn, Mo, Pb, Ti and Zn of non-agricultural soil and agricultural soils in the study area, showed that the highest level of pollution is distributed near and along the Lean River, especially in the neighboring and surrounding Dexing and Leping mining area.