Preliminary study on radiocarbon AMS dating of pollen

17 samples were collected from aeolian and lacustrine profiles within the environment sensitive zone of the Loess Plateau, and an experimental method was established which is suitable for pollen extraction from aeolian sediment. A comparative study of pollen dating was carried out using the accelerator mass spectrometry (AMS)¹⁴C dating of known age samples, and then an experiment with the pollen concentrates was performed. The results indicate that pollen that has been deposited simultaneously with sediment in a stable environment can provide reliable ages. This technique will provide a way of improving the chronological framework for the Loess Plateau since the late Pleistocene. The^I4c dating was combined with field investigations, and from the geological record within this zone, evidence was extracted of four major monsoon precipitation changes during the transition from the late Pleistocene to Holocene. Project supported by the National Natural Science Foundation of China (Grant Nos. 49894170, 49725308), Chinese Academy of Sciences (Nos. KZ-951-A1-402& KZ-952-S1-419), and State Committee of Science and Technology of China.     

Hydrogen and oxygen isotope studies of metamorphic fluid-rock interactions in the Dabie Mountains

Hydrogen and oxygen isotope studies were carried out on mineral separates from high to ultrahigh pressure metamorphic rocks at Huangzhen and Shuanghe in the eastern Dabie Mountains, East China. The δ¹⁸O values of eclogites cover a wide range of −5‰ to+9‰, but the δD values of micas fall within a narrow range of −85% to −70‰. Both equilibrium and disequilibrium oxygen isotope fractionations were observed between quartz and the other minerals, with reversed fractionations between omphacite and garnet in some eclogite samples. The δ¹⁸ O values of −5‰ to −1‰ for some of the eclogites represent the oxygen isotope compositions of their protoliths which underwent meteoric water-rock interaction prior to plate subduction. The preservation of oxygen isotope heterogeneity in the eclogites implies a channelized flow of fluids during progressive metamorphism caused by rapid subduction. Retrograde metamorphism has caused oxygen and hydrogen isotope disequilibria between some of the minerals, but the fluid for retrograde reactions was internally buffered in the stable isotope compositions. Project supported by the Chinese Ministry of Science and Technology (Grant No. 95-Pre-39), the National Natural Science Foundation of China (Grant Nos. 49794042, 49473173 and 49453003) and the Chinese Academy of Sciences (Grant No. KZ951-A1-401-5)     

新疆乌鲁木齐台地电阻率变化及震兆特征

以乌鲁木齐地电阻率观测资料为依据,在展示其变化特征的基础上,对该地电阻率资料异常变化与近区中强地震及部分远区的大地震之间的关系进行了归纳、分析与讨论。对地电阻率前兆异常形态与地震之间的关系进行了探讨。     

贻贝超氧化物歧化酶的分离纯化和部分性质

采用热变性－硫酸铵分级沉淀－Ｓｅｐｈａｄｅｘ Ｇ－１００和ＤＥ５２柱层析的方法从贻贝中分离纯化铜锌超氧化物歧化酶,并对其部分性质进行分析鉴定。结果该酶的比活力为９４５３．３Ｕ／ｍｇ（ｐｒｏｔｅｉｎ）,提纯倍数为６０９．９,对ＫＣＮ和Ｈ２Ｏ敏感,Ｔ氏液和ＳＤＳ对酶活性没影响,对热较稳定。     

青岛滨海地质旅游

青岛滨海旅游具有丰富的地质资源,合理地开发会使其具有专业特色,娱乐性和趣味性。滨海地质旅游将促进旅游业的发展,在向现代化国际城市中发挥作用。     

鲈鱼苗烂鳃、烂尾病病原菌的研究

１９９７年４～５月,对花鲈（Ｌａｔｅｏｌａｂｒａｘｊａｐｏｎｉｃｕｓ）鱼苗期细菌性烂鳃和烂尾病的病原菌进行了研究。从具有明显症状的病鱼的病灶组织分离到２株致病菌Ｃ－１和Ｗ－１,经人工感染及从人工感染发病鱼体再分离的Ｗ－４和Ｗ－５菌株的再感染试验结果表明,所分离的细菌为鲈鱼苗烂尾,烂鳃病的致病菌。经６４项生物学特性,生理生化特征测试结果表明,这４株菌可归为一类,同属于鳗弧菌（Ｖｉｂｒｉｏａｎｇｕｉｌａｒｕｍ）。药敏试验结果表明,痢特灵、ＣＩＮ１００、ＭＥＬ２５、呋喃妥因、氯霉素、磺胺药＋ＴＭＰ和美洛西林等７种药物对病原菌有显著的抑制作用。     

Experimental study on strain field evolution around a simulated thrust fault

Earthquakes result from continuous geodynamic processes. A topic of significant interest for the scientific community is to elaborate on the phenomena governing the faulting and fracturing of crustal rocks. Therefore, in this study, uniaxial compressive shear failure experiments were conducted on Fangshan marble rock samples with a prefabricated slot to simulate thrust faulting. The center of each marble plate (105 mm × 80 mm × 5 mm) was engraved with a 30-mm long double-sided nonpenetrating slot (depth: 2 mm, width: 0.5 mm). The deformation and destruction processes of the rock surface were recorded using a high-speed camera. The digital image correlation method was used to calculate the displacement and strain distribution and variation at different loading stages. The accumulative and incremental displacement fields u and v , strain field e_x and e_y, and shear strain e_xy were analyzed. When the loading level reached its ultimate value, the strain field was concentrated around the prefabricated slot. The concentration reached a maximum at the ends of the prefabricated slot. The magnitude of shear strain reached 0.1. This experiment contributes to our understanding of the dynamic process of active faulting.     

福建闽江水口水库凤眼莲空间分布特征及其动态

为研究闽江水口水库凤眼莲空间分布特征及动态变化,根据2001-2009年水口库区无云覆盖的24幅卫星遥感影像,构建研究区域凤眼莲干流-支流分布的空间结构,并通过建立端元的混合象元线性分解模型,对福建省水口水库不同时间、不同区域的凤眼莲分布特征进行系统分析,结果表明,随着时间的推移,凤眼莲的暴发区逐渐向下游迁移,同时,支流对研究区域凤眼莲的面积有重要影响,特别是河流较长、周边有人口居住的支流是凤眼莲源头治理的重点;各种人为或自然原因造成的水体富营养化、河流流速变缓等是凤眼莲泛滥的重要原因.建议针对研究区域上游及其周边进行养殖污染、工业污染整治,强化对污染源的监督管理,推进生态环境建设与保护,建设生态功能保护区等.本研究可为了解水口水库的凤眼莲时空分布规律,进而制定相应的预防与控制管理措施提供必不可少的数据基础和理论依据.     

1932年昌马7.6级地震震源区及其邻近地区尾波衰减特征研究

Q_c值是描述地震波在地下衰减变化的重要物理参数之一,其大小能够反映该地区地震活动的强弱和地下介质非均匀性程度。基于Aki的单次散射模型,选用2008—2020年间昌马地震震源区及其周边区域5个固定数字化地震台站接收到的震中距小于100 km、M>2.0的1 252次地震记录,计算分析该区域的尾波衰减特征。研究结果表明：(1)窗长为20 s、30 s和40 s的Q_c值与频率f的衰减关系分别为Q_c=(71.76±8)f⁽(1.10±0.04))、Q_c=(103.83±17)f⁽(1.04±0.06))和Q_c=(120.77±22)f⁽(1.00±0.06));(2)通过克里金插值绘制的Q_c值空间分布图表明昌马地震震源区及其周边区域的Q_c值分布与地质构造、地震活动性存在较明显的相关性;(3)研究区域的Q₀值较低,η值较高,与该区域构造活动性较强的特...