川西地区中二叠统-下三叠统碳酸盐岩碳氧同位素特征

 针对川西地区中二叠统-下三叠统碳酸盐岩,通过分析3 个剖面的碳氧同位素数据,计算Z 值及古温度,并结合沉积相、古生物等,对该区域碳酸盐岩碳氧同位素演化特征及古环境进行了系统研究。结果表明,川西地区中二叠统-下三叠统碳酸盐岩的δ¹³C 值为-3.90‰~2.80‰,主要值域为-2.80‰~2.80‰,均值为-0.04‰;δ¹⁸O 值为-9.70‰~-1.80‰,主要值域为-8‰~-4‰,均值为-6.60‰。研究区古环境基本处于海相环境,东北边缘水体相对较深,西南边缘水体相对较浅,海水温度为8.8~68.4℃,主要值域为16~33℃,属于温暖或炎热的亚热带气候,经历了栖霞期-茅口期、吴家坪期-长兴期、飞仙关期-嘉陵江期3 次大的海平面变化旋回,且其间各有若干次次级旋回。     

CH3Cl分子间相互作用的理论研究

在MP2／6—311＋＋G（3d,3p）电子相关校正水平上,对CH3Cl二聚体可能存在的几何构型进行全自由度能量梯度优化,发现有三种势能面上极小点的构型。进一步在高级电子相关校正的MP4SDTQ、CCSD（T）／6—311＋＋G（3df,3pd）方法水平上,对其中具有平面环状C2h对称性的总能量最小的构型进行精确计算,得到CH3Cl二聚体的结合能为-8．764KJ／mol。能量分解表明在分子间相互作用中色散与静电相互作用相近,色散与静电作用能分别占总吸引能的41．8％和38．1％。分析了二聚体的谐振频率,并进行了频率归属。     

三种纳米材料C_(70),C_(60)Cl_6和C_(60)Ph_6引起细胞自噬的现象

为了进一步研究富勒烯家族及其衍生物引起细胞自噬的现象,运用荧光显微镜、透射电子显微镜、蛋白免疫印迹等技术,对水溶性的纳米C70,C60Cl6和C60Ph6诱导的细胞自噬现象进行了初步探讨.实验结果显示,C70,C60Cl6和C60Ph6稳定分散于水中形成的纳米颗粒,均能诱导HeLa细胞产生自噬现象,揭示了富勒烯家族及其衍生物在生物医药领域更广泛的研究和应用价值.     

S同位素示踪热液矿床成矿物质来源综述

具有明显分馏效应的硫同位素以各种含硫物种广泛赋存于热液成矿作用过程中,因此硫同位素成为示踪热液矿床成矿物质来源的主要方法之一。本文在总结前人研究基础上,综述了应用硫同位素在研究热液矿床成矿物质来源问题上的多解性,认为硫同位素示踪应用须在了解热液矿床地质前提下,准确区分成矿期次,判别硫同位素分馏平衡状态,结合Ohmoto模式才可以准确赋予同位素的地质意义。     

Comparison of the carbon isotope composition of total organic carbon and long-chain n-alkanes from surface soils in eastern China and their significance

Surface soil samples collected over a high spatial resolution in eastern China were analyzed for carbon isotope composition(δ 13C) of total organic carbon(TOC) and higher plant-derived long-chain n-alkanes,with the latter reported as weighted mean values.The two sets of δ 13C values are significantly correlated and show similar trends in spatial variation.The spatial distribution of δ 13C shows less negative values in the mid-latitudes between 31°N and 40°N and more negative ones at higher and lower latitudes.This is consistent with previously reported carbon isotope data from surface soil phytoliths in the same region and suggests that the mid-latitude area provides relatively favorable growing conditions for C4 plants.Furthermore,δ 13C values of both TOC and long-chain n-alkanes from 12 surface soil samples collected from a small grassland in north China displayed similar carbon isotope values and the difference between paired δ 13C of a soil samples remains relatively constant.Our data demonstrate that in eastern China,soil δ 13C composition of both TOC and long-chain n-alkanes is effective indicators of C3/C4 ratios of the prevailing vegetation.This work suggests that -22‰ and -32‰ are good estimated end members for the weighted mean δ 13C values of long-chain n-alkanes(C27,C29 and C31 n-alkanes) from soils under dominant C4 or C3 vegetation,allowing us to reconstruct paleovegetation trends.     

广西凤山县鸳鸯泉水文地质成因探讨

【目的】研究凤山县鸳鸯泉的水文地质成因,为鸳鸯泉这一地质奇观提出科学的解释。【方法】根据实地调查和现场试验,结合地层岩性、地质构造以及岩溶发育情况,查明鸳鸯泉的岩溶水文地质条件;根据地下水示踪试验,确定鸳鸯泉的源头和主要的岩溶含水介质类型,并通过稳定氢氧同位素和钙锶比(Ca/Sr)分析,研究管道介质岩溶大泉的补径排过程和水循环特征。【结果】鸳鸯泉的源头为年里落水洞补给的外源水,公塘和母塘两个出口的主径流管道基本一致;鸳鸯泉具有以岩溶管道为主的含水介质特征,以及快速流的补给、径流和排泄过程。这种水文地质现象的成因与管道流集中排泄的方式有关。【结论】鸳鸯泉同属于一个管道系统,管道流的两个出口在水循环速度上存在差异,相比公塘,母塘具有较短的径流途径和较快的更新速率。     

Age and genesis of the Myanmar jadeite: Constraints from U-Pb ages and Hf isotopes of zircon inclusions

Myanmar jadeite (jadeitite) is well known for its economical value and distinctive tectonic locality within the collisional belt between India and Eurasian plates. However, it is less studied for its genesis and geodynamic implications due to precipitous topography, adverse weather and local military conflicts in the area. By means of combined ICP-MS and LA-MC-ICPMS techniques, we have carried out in-situ trace elements, U-Pb and Lu-Hf isotopes for zircon inclusions in a piece of jadeite gem sample. CL imaging suggests that the zircons are metasomatic in origin, and contain mineral inclusions of jadeite and omphacite. Seventy-five analyses on 16 grains of the zircons yield a U-Pb age of 158 ± 2 Ma. The Myanmar zircons differ from other types in that they have no significant Eu anomalies despite high HREE concentrations. Measured ¹⁷⁶Hf/¹⁷⁷Hf ratios range from 0.282976 to 0.283122, with an average value of 0.283066 ± 7; ε_Hf(t) value of 13.8 ± 0.3 (n=75). These results indicate that the Myanmar jadeite was formed in the Late Jurassic, probably by interaction of fluid released from subducted oceanic slab with mantle wedge. Therefore, its formation has no genetic relationship to the continental collision between Indian and Euroasian plates. Supported by National Natural Science Foundation of China (Grant No. 40673039) and the Science Plan Foundation of Guangdong (Grant No. 2007B031200005)     

[Co(2，3tri)(pz)Cl]2+体系配合物水解-重排机理研空

本文提出了一个「Ｃｏ（三元胺）（二元胺）Ｃｌ」＾２＋型的配合物及其异构体的重排机理模型,它包含了所有异构体间的转换关系,这一模型表面式异构体在重排过程中的重要性,利用对映异构体旋光性质及其可能的变化提出了可能存在一与经典模式不同的中间体假设。     

峨眉山柿子坪热田地下水碳氧同位素特征初步研究

在峨眉山柿子坪热田地质调查及热水勘探过程中 ,采用了碳、氧同位素地球化学方法 ,结果发现不同成因类型的地下水其碳、氧同位素组成特征各不相同 ,为查明地下热水的形成条件提供了重要依据 ,表明用地下水中 HCO-3 的碳、氧同位素组成来研究地下热水系的发育特征是有前景的     

华南晚泥盆世腕足动物壳体保存状况及其氧碳同位素比较研究

对华南湘中地区上泥盆统弗拉/法门(F/F)界线附近的几种腕足动物化石壳体结构所进行的详细研究表明,其原始结构主要表现为两种类型：一是具有棱柱状第三层,二是缺失棱柱状第三层。基于壳体保存程度的详细分析,以阴极发光程度、壳体显微结构为参数建立了壳体成岩作用改造程度的量化模式,经化石壳体氧、碳同位素值的验证,这一模式基本可以用来对不同保存环境下的样品进行筛选。在对比研究中发现,以无洞贝目(Atrypida)为代表的具有柱状第三层结构的样品不仅在保存状况上优于只具有纤维层结构的壳体,而且其氧、碳同位素数值的分布也较为集中,从而说明无洞贝目的壳体是进行氧、碳同位素研究较为理想的材料。