硫的非质量分馏在晚太古代环境中的应用研究进展

硫的非质量分馏是研究大气环境变化的重要指示剂,在太古代缺氧的环境下,二氧化硫的光化学反应会产生带正和负δ~(33)S的两个硫同位素端元,其产物分别赋存于黄铁矿和古海水硫酸根中。但前人的研究多集中于黄铁矿端元,而对于硫酸根,由于缺乏指示矿物,其研究较为薄弱且多有争议。从硫的非质量分馏产生机理、晚太古代地质记录中硫的非质量分馏的研究及大气化学实验的模拟研究三个方面进行综述,结合研究实例,分析了古海水硫酸根的可能来源,预测了硫的非质量分馏值的范围,提出晚太古代海水硫酸盐硫的非质量分馏效应将是今后研究的重点。     

大陆俯冲带流体活动和元素迁移:大别-苏鲁超高压变质岩和变质脉的研究

大别-苏鲁超高压变质岩和变质脉的岩石学及地球化学研究表明,在大陆俯冲带流体-岩石反应过程中,伴随着显著的元素迁移和同位素分馏.大别-苏鲁造山带高压脉中单矿物(如金红石和多硅白云母)具有明显的生长环带,指示变质脉是流体-岩石相互作用的结果.较高的流体/岩石比和强烈的二者相互作用是导致Nb-Ta迁移和分异的主导因素.对中国大陆科学钻探主孔石榴橄榄岩、榴辉岩和变质脉的Li和B同位素地球化学研究,表明在陆壳深俯冲和折返过程中Li和B发生了明显的分馏且表现出不同的地球化学行为.富集Si,Al,Na,LILE(如Rb,Ba和Sr)和HFSE(如Nb,Ta和Ti)的高压变质脉的存在以及不同岩性接触带高度变化的地球化学特征指示,在峰期超高压变质条件下可能形成了超临界流体,它对微量元素的迁移起到了非常重要的作用.     

硼掺入Mg(OH)2过程中的硼同位素分馏

为确定B掺入Mg(OH)₂时的形式及掺入过程中硼同位素组成的变化, 进行了不同设定pH (pH_设定)的人工合成无Mg海水中B掺入Mg(OH)₂的实验. 结果表明, B掺入Mg(OH)₂非常迅速, 4 h能达到平衡, 平衡后Mg(OH)₂中B浓度[B]_固和固相与溶液相间的分配系数K_d随pH_设定的升高而降低. 而且最高的[B]_固和K_d均远高于B被金属氧化物或黏土矿物吸附时的对应值, 表明B具有很强的掺入Mg(OH)₂的能力. 平衡时溶液相的δ¹¹B_液f均低于原始溶液的δ¹¹B_液i, 计算的Mg(OH)₂与平衡溶液间的硼同位素分馏系数α_固-液变化范围为1.0186~1.0220, 平均值为1.0203. 这充分表明, B掺入Mg(OH)₂时¹¹B优先进入固相, 这是B(OH)₃优先掺入的结果. B(OH)₃与Mg(OH)₂间的沉积反应是B(OH)₃掺入的直接原因. B(OH)₃与Mg(OH)₂间的沉积反应和B(OH)₄⁻在Mg(OH)₂上吸附可能同时存在, 并以沉积反应为主, 它们决定了B掺入Mg(OH)₂时硼同位素特征. 与B只以B(OH)₄⁻形式掺入生物碳酸盐不同, B以B(OH)₃和B(OH)₄⁻两种形式同时掺入Mg(OH)₂, 并以B(OH)₃优先掺入为主, pH_设定越低掺入的B(OH)₃比例越高. 由于Mg(OH)₂普遍存在于石珊瑚中, 这将严重影响珊瑚的硼同位素组成δ¹¹B与海水pH的定量对应关系, 因此会给δ¹¹B作为古海水pH的代用指标带来极大的不确定性.     

浙江黄双岭萤石矿的同位素研究

文章公布了浙江黄双岭萤石矿的氢、硫、锶和铅同位素分析结果,讨论了成矿溶液和成矿物质来源,估计黄双岭萤石矿的成矿年龄大约为107Ma。     

美国Wallapai矿区Mineral Park斑岩型矿床早期矿脉中硬石膏的氧同位素组成

本文报道了美国亚利桑那Wallapai矿区Mineral Park斑岩型矿床早期矿脉(AM和AC)中硬石膏的氧同位素组成,依据包体均一温度及硫同位素温度计算成矿溶液的δ~(12)O值(纯水),运用同位素分馏理论讨论AM和AC矿脉成矿溶液的来源和演化。     

渤中坳陷BZ26-2油田油气地球化学特征及其成藏意义

渤中坳陷BZ26-2油田发现正常油藏和凝析气藏两类油气藏.馆陶组原油中25-降霍烷系列与完整的链烷烃系列共存表明至少存在两期油气成藏.通过原油单体烃碳同位素和生物标志化合物的对比表明,油田具有双向油气来源,凝析油气来源于北部渤中凹陷,而正常原油主要来源于南部黄河口凹陷.原油异常密度梯度和轻烃参数表明,深层凝析气藏为热成因,浅层凝析气藏为蒸发分馏成因.综合分析表明BZ26-2油田是一个具有双向油气来源、多期次充注、经历多种后生作用的复合成因油气田.     

降低延迟焦化加热炉燃料气单耗的原因分析与措施

加热炉是延迟焦化装置的核心设备,中部某炼厂延迟焦化加热炉存在燃料气单耗偏高的问题,通过对燃料气单耗影响因素原料性质、分馏系统和炉管结焦的分析,并采取了相关措施,取得了显著效果。     

常减压装置改炼轻质原油对装置能耗的影响

常减压装置能耗主要与原油性质、产品方案、装置处理量及操作等因素有关。其中,原油性质对能耗的影响复杂,轻质原油气化率高,分馏系统拔卅率高,工艺用能多,但可回收的热量也大。本文,笔者将通过一个实例来说明这个问题。     

Application of chemical fractionation and X-ray powder diffraction to study phosphorus speciation in sediments from Lake Hongfeng,China

Based on the techniques of sequential extraction and X-ray powder diffraction (XRD), the distribution characteristics of phosphorus speciation were investigated in 13 sediment samples from Lake Hongfeng, an important drinking water source for Guiyang with a typical karstic limestone environment. The total phosphorus (TP) concentrations in the sediments ranged from 973.36 to 2334.18 mg/kg with a mean concentration of 1635.87 mg/kg (dry weight), and it was evident that the phosphorus level in the sediments was high compared with other eutrophic lakes such as Lake Chaohu and Lake Xihu. The results of the two methods, sequential extraction and XRD, demonstrated the presence of different phosphorus species in the lake sediments. Being compatible with local geophysical characteristics, the results of sequential extraction techniques indicate that the average percentages of dissolved phosphorus (DP), aluminum-bound phosphorus (Al-P), iron-bound phosphorus (Fe-P), calcium-bound phosphorus (Ca-P) and organic phosphorus (OP) in the sediments were 0.40%, 7.06%, 5.07%, 45.48% and 38.49%, respectively. Notably, the concentrations of inorganic phosphorus (IP) were higher than those of OP, and the IP consisted primarily of Ca-P. The high concentrations of Ca-P may temporarily control the release of phosphorus from the sediments because it is a relatively stable, inert and non-bioavailable phosphorus fraction. The results of XRD analysis indicated that, among phosphorus species, AlPO₄ was found in all sediment samples at relatively high concentrations. Moreover, the TP concentrations in the sediments were high; thus the release potential and bioavailability of phosphorus in the sediments was important. Further statistical analyses of the results revealed significant correlations between phosphorus species in the sediments with two extractable principal components and four selectable cluster levels allowing interpretation of possible origins of phosphorus loading and transformation mechanisms of phosphorus species. Furthermore, available remediation measures were briefly assessed for the lake while considering its distinct environmental features.     

青海省拉脊山一带金矿硫同位素特征及矿质来源初探

通过对同位素样品的统计分析,阐述了拉脊山一带金矿硫同位素特征,对金矿硫源及同位素分馏进行了分析、解释,认为该区硫为内生硫、幔源硫,对金矿的物质来源进行了初步探讨,金最初与硫共生,且来自上地幔。