荒漠植物花棒耐盐性的傅立叶红外光谱法研究

试验以荒漠植物花棒幼苗为材料,应用傅立叶红外光谱（FTIR）法研究了NaCl胁迫下花棒叶片主要有机化合物含量和蛋白质结构的变化以及叶片K+和Na+含量。结果表明,叶片Na+、K+含量随着0~255 mM NaCl盐胁迫逐渐增强而变化,导致Na+/K+比值逐渐降低,显示出盐胁迫下花棒幼苗具有”吸钾排纳”特性。花棒幼苗再170 mM NaCl的高浓度胁迫下24 h,叶片中蛋白质、酯类和碳水化合物含量大幅度增加。花棒的蛋白质二级结构中1 665/1 638 cm-1比值的逐渐降低。揭示出花棒植株通过增强蛋白质、酯类和碳水化合物合成代谢调控能力抵御盐胁迫的损伤,而且花棒蛋白质二级结构更趋稳定,与叶片中Na+/K+比值的变化趋势显著相关。因此花棒为了适应高浓度盐胁迫,具有叶片蛋白质、酯类快速合成以及蛋白质构象更趋于稳定的积极响应。     

地质样品中高精度铬同位素分析纯化技术研究进展

随着多接收器热电离质谱仪(MC-TIMS)和多接收器电感耦合等离子体质谱仪(MC-ICP-MS)的发展,高精度铬(Cr)同位素测试已成为可能。铬同位素在地球、环境、农业生态和宇宙化学等科学领域中已显示出良好的应用潜力。然而,样品的纯化分离、干扰和仪器质量分馏的校正,依然是制约铬同位素高精度测试的重要因素。本文在近年来铬同位素分析技术最新进展的基础上,结合本课题组已有的研究,对陨石、地质和环境等各类样品中铬同位素的分离纯化方法、MC-ICP-MS测试中干扰与质量歧视校正等进行了详细综述。本文认为,阴阳离子树脂交换联用与过硫酸钾等强氧化剂的结合,可以进行低铬高基质样品的有效纯化,是一种较为普适性的纯化方法。使用铬同位素双稀释剂校正质量歧视效应,在MC-ICP-MS的中高分辨与静态测量模式下,不仅可以有效分开多原子离子的干扰,而且也可以进行高精度铬同位素分析,其δ~(53/52)Cr的分析精度与TIMS相当,可以达到0.04‰(2SD),且最低测试浓度可低至10ng,能够实现超微量铬的同位素分析。     

Petroleum accumulation in the deeply buried reservoirs in the northern Dongying Depression,Bohai Bay Basin,China: New insights from fluid inclusions,natural gas geochemistry,and 1-D basin modeling

The deeply buried reservoirs (DBRs) from the Lijin, Shengtuo and Minfeng areas in the northern Dongying Depression of the Bohai Bay Basin, China exhibit various petroleum types (black oil-gas condensates) and pressure systems (normal pressure-overpressure) with high reservoir temperatures (154–185 °C). The pressure-volume-temperature-composition (PVTX) evolution of petroleum and the processes of petroleum accumulation were reconstructed using integrated data from fluid inclusions, stable carbon isotope data of natural gas and one-dimensional basin modeling to trace the petroleum accumulation histories.The results suggest that (1) the gas condensates in the Lijin area originated from the thermal cracking of highly mature kerogen in deeper formations. Two episodes of gas condensate charging, which were evidenced by the trapping of non-fluorescent gas condensate inclusions, occurred between 29-25.5 Ma and 8.6–5.0 Ma with strong overpressure (pressure coefficient, P_c = 1.68–1.70), resulting in the greatest contribution to the present-day gas condensate accumulation; (2) the early yellow fluorescent oil charge was responsible for the present-day black oil accumulation in well T764, while the late blue-white oil charge together with the latest kerogen cracked gas injection resulted in the present-day volatile oil accumulation in well T765; and (3) the various fluorescent colors (yellow, blue-white and blue) and the degree of bubble filling (F_v) (2.3–72.5%) of the oil inclusions in the Minfeng area show a wide range of thermal maturity (API gravity ranges from 30 to 50°), representing the charging of black oil to gas condensates. The presence of abundant blue-white fluorescent oil inclusions with high Grain-obtaining Oil Inclusion (GOI) values (35.8%, usually >5% in oil reservoirs) indicate that a paleo-oil accumulation with an approximate API gravity of 39–40° could have occurred before 25 Ma, and gas from oil cracking in deeper formations was injected into the paleo-oil reservoir from 2.8 Ma to 0 Ma, resulting in the present-day gas condensate oil accumulation. This oil and gas accumulation model results in three oil and gas distribution zones: 1) normal oil reservoirs at relatively shallow depth; 2) gas condensate reservoirs that originated from the mixture of oil cracking gas with a paleo-oil reservoir at intermediate depth; and 3) oil-cracked gas reservoirs at deeper depth.The retardation of organic matter maturation and oil cracking by high overpressure could have played an important role in the distribution of different origins of gas condensate accumulations in the Lijin and Minfeng areas. The application of oil and gas accumulation models in this study is not limited to the Dongying Depression and can be applied to other overpressured rift basins.     

Hydrocarbon charging and accumulation history in the Niudong Buried Hill Field in the Baxian Depression,eastern China

The Niudong Buried Hill Field, which lies in the Baxian Depression of the Bohai Bay Basin, is the deepest oil/gas accumulation in eastern China. Its Precambrian dolomite reservoir occurs at burial depths of 5860 m–6027 m. This paper attempts to document the hydrocarbon charging and accumulation history in this field, which could greatly enhance the understanding of the mechanisms for the formation of deep hydrocarbon accumulations. Our previous study of oil trapped in fluid inclusions has demonstrated that the ratio parameters of the fluorescence spectral intensities at 425 nm and 433 nm (Q_425/433 ratio), and at 419 nm and 429 nm (Q_419/429 ratio) can be more effective for revealing hydrocarbon charging history than the previously-used fluorescence parameters such as Lambda max and red/green quotient as well as fluorescence colors. The hydrocarbon charging and accumulation history in the Niudong Buried Hill Field was studied with an integrated approach involving the application of these two spectral parameters of petroleum inclusion fluorescence as well as utilization of other data including homogenization temperatures of aqueous inclusions coeval with petroleum inclusions, and cross-cutting relationships of cements and “oil veins” in pores and fractures. The results indicate that the dolomite reservoir in the Niudong Buried Hill Field experienced three episodes of hydrocarbon charging. In the first two episodes (between 38.5Ma and 25Ma), the low mature and mature oils, which were derived from source rocks in the Sha-4 Member of the Eocene Shahejie Formation, migrated into the reservoir, but part of them leaked out due to normal faulting at the updip margin of the buried hill. These early-charged oils were preserved mainly in small pores in micritic dolomites by oil-wettability and capillary pressure. In the Neogene, the basin subsided as a whole and local faults at the updip margin became inactive and played a sealing role. By approximately 13Ma, the source rocks became highly mature and the generated hydrocarbons then migrated into the reservoir and accumulated. Therefore, the last charging is the most important for hydrocarbon accumulation in the Niudong Buried Hill Field.     

黑色岩型铂族矿物中铂钯金相态ICP-MS分析方法研究

黑色岩是近年发现的铂族元素重要载体,由于其金属来源的多样性及成矿作用的复杂性,对于铂族元素在该类矿物中的分布及富集形式目前并不十分清楚,这也是造成黑色岩中铂族元素测定不稳定的主要原因。本文根据黑色岩的矿物性质及组成,将黑色岩中Pt、Pd、Au的赋存状态划分为:可交换相、有机结合相、硫化物结合相、残渣相。通过应用硫氰酸钾+氰化钠作为解吸剂,有效抑制了黑色岩中有机碳对各相态中Pt、Pd、Au的吸附,采用分离富集ICP-MS法测定了Pt、Pd、Au在各相态中的分布。结果表明:(1)各元素各相态的提取总量与该元素在样品中的总量之比分别为Pt 94.4%~101.0%,Pd 95.8%~101.0%,Au 96.7%~102.0%,说明本方法具有较好的准确性和重现性;(2)黑色岩矿物中Pt、Pd、Au的富集不仅具备亲硫性,而且与有机碳形成的地质条件、地质背景有明显的相关性,此结果为研究黑色岩中铂族元素所处的地球化学环境及其成矿规律提供了重要信息。     

LA-ICP-MS工作参数优化及在锆石U-Pb定年分析中的应用

将激光器(LA)和电感耦合等离子体质谱仪(ICP-MS)联用避免了溶液分析繁琐、耗时的前处理操作,减少了样品制备过程中可能带来的污染,同时又具备分析成本低、测试速度快、分析数据精度高等优势。本文将LA与ICP-MS联接使用,通过激光能量密度和剥蚀频率组合来讨论较低的元素分馏效应,同时匹配RF功率、采样深度、载气及He气流速等主要工作参数以获得较高的元素信号灵敏度和稳定性,从而得到仪器最优工作参数组合,建立了可靠的锆石U-Pb定年方法。通过对锆石标样91500、GJ-1及Ple2ovic互测结果表明,其206Pb/238U加权平均年龄分别为1063.9±6.0 Ma(2σ,n=20)、600.3±2.6 Ma(2σ,n=27)及337.6±1.7 Ma(2σ,n=20),测试结果准确度和精度均在1%范围内,与前人报道的误差范围一致。使用优化后的仪器参数对来自鄂东南铜绿山矿区石英正长闪长玢岩岩体中的实际锆石样品进行测试,获得其206Pb/238U年龄与前人研究结果基本一致,表明本法能准确地对锆石进行定年分析。     

混合酸比例对ICP-MS/OES测定地球化学样品中多元素的影响

应用电感耦合等离子体质谱/发射光谱仪(ICP-MS/OES)测定地球化学样品中的多元素时,通常采用混合酸(盐酸-硝酸-氢氟酸-高氯酸)分解试样,但不同比例的混合酸对试样的分解效果影响极大,导致测试结果中经常出现铬、锰、铁、铝、钛及部分稀土元素测定结果偏低、精密度不理想的情况。本文通过改变混合酸中各类酸的混合比例,采用逆王水-氢氟酸-高氯酸分解试样,逆王水提取,使上述元素获得了较为理想的分解效果,特别是这些元素含量较高的样品分解效果的改善尤为显著。实验证明:当取样量为0.100 g时,采用8 mL逆王水、6 mL氢氟酸、3 mL高氯酸分解试样,8 mL逆王水提取,用国家一级标准物质进行验证,测试结果的相对标准偏差(n=6)为0.34%~4.02%,本方法精密度和准确度均满足地质实验室质量管理规范要求,可快速、准确、批量测定地球化学样品中的多元素。     

多仪器协同-X射线荧光光谱法在区域地球化学调查分析中的应用评价

在区域地球化学调查样品多元素分析测试中,通常将XRF、ICP-OES、ICP-MS、AFS等仪器相互配套使用,但由于XRF测定20多个元素,与其他仪器测定速度并不同步,影响了项目的整体进度。本方法对配套方案进行了优化,调整了XRF部分测量元素的分析方法,即将基体校正和谱线重叠校正涉及Na_2O、MgO、V的数据由ICP-OES法测量;Cu、Pb、Zn、Mn、Th的数据由ICP-MS法测量;As、Bi的数据由AFS法测量。优化后的XRF方法测量元素减少为16个:SiO_2、Al_2O_3、Ca O、TFe_2O_3、K_2O、Ti、P、Sr、Ba、Zr、Nb、Y、Rb、Br、Ga、Cl。通过设计的XRF数据处理程序,实现了这些不同方法的测量数据共享,利用ICP-OES、ICP-MS、AFS等测量数据对XRF数据进行基体效应和谱线重叠干扰校正。本方法精密度(RSD,n=12)为0.55%~8.22%,准确度(ΔlogC)为0.000~0.031,用国家标准物质及实际样品验证的结果满足区域地球化学调查样品分析测试质量规范要求。本方案减少了XRF直接测量元素的数量,提高了多种仪器协同的分析效率。