辉绿岩裂缝对其磁组构的影响

磁组构是由岩石中磁性矿物定向分布而产生的组构特征,因此磁组构分析是研究岩石组构常用的技术手段,它具有 见效快、灵敏度高、无损样品等特点,近年来得到广泛应用。然而在磁组构研究工作中钻取定向样品或定向手标本时,常 常会遇到天然样品含有裂缝且裂缝中充填大量近地表沉积物和自生矿物。本文针对辉绿岩裂缝充填物对其磁组构结果的影 响程度做了详细研究,选用160个含裂缝的辉绿岩岩芯定向样品,通过对比去除裂缝充填物前后的磁组构变化,发现实验 前后所有样品磁化率大小变化率平均值<1%,磁组构方向变化平均值<1°,因此认为辉绿岩裂缝物质对其磁组构影响甚微。 矿物学和岩石磁学分析表明裂隙充填物主要为石英、长石,以及少量赤铁矿、黄铁矿和绿泥石等表生矿物。而辉绿岩的携 磁矿物主要是亚铁磁性的磁铁矿,其磁化率强度约为同等质量裂缝填充物的30倍,致使辉绿岩中的裂隙充填物对磁组构的 影响很小。     

秦皇岛市区断裂活动性的SEM研究

近年来,应用断层泥扫描电子显微(SEM)构造来研究断裂的活动性,已引起了国内、外地震地质和工程地质的重视。本文通过对秦皇岛市区几条断裂带断层泥和断层泥中石英颗粒表面SEM构造特征的研究,对断裂带的相对活动时限及活动特征进行了探讨。研究成果与野外宏观调查、现场仪器测试、遥感101系统图象处理结果基本吻合,在微观领域为市区断裂活动性研究提供了依据。这说明该方法在工程地质领域具有重要的实际应用价值。     

Induced modifications of kaolinite under ionizing radiation: an infrared spectroscopic study

Radiation effects on kaolinite were investigated using He⁺ ions of 1.5 MeV at radiation doses up to 4.3 × 10⁸ Gy, which are comparable to the doses expected for clay barriers in high-level nuclear waste repositories. The concentration of paramagnetic radiation-induced defects in kaolinite reaches 2 × 10¹⁶ spins/mg (400 at. ppm), as determined by electron paramagnetic resonance spectroscopy. The broadening of X-ray diffraction patterns and transmission infrared (IR) absorption bands is mostly related to the structural strain induced by radiation-induced point defects. The broadening of IR absorption spectra is analyzed using an autocorrelation approach and is related to a change in the distribution of vibrational frequencies due to crystal heterogeneities. We theoretically analyze how the effective dielectric properties of kaolinite samples depend on macroscopic parameters and how irradiation can modify some of them. Irradiation leads to an increase in the electronic polarizability of kaolinite particles, related to the accumulation of radiation-induced electronic point defects.     

广州市零售商业中心的居民消费时空行为及其机制

居民消费行为的空间选择及其影响因素是地理学的重点关注领域,已有研究对行为中时间选择、时空关系及内在机制的研究相对缺乏。为揭示居民消费时空行为形成的影响因素以及各因素内在相互作用机制,基于2016年广州城市居民消费行为调查数据,分析消费者到大型商业中心内消费的时空特征,构建结构方程模型,探讨消费时空行为影响因素和作用机制。研究表明：居民在商业中心的消费行为存在明显的时空差异。在影响路径方面,消费者社会经济属性通过影响消费偏好导致消费时空行为的差异,商业空间属性既可以直接影响消费时空行为,也可以通过影响消费偏好而间接对其施加影响,消费偏好既可以直接影响消费时空行为,又是消费者社会经济属性和商业空间属性影响消费时空行为的中间变量。在显著性因素方面,年龄、家庭结构、在广州居住时间、就业状况、家庭月收入等消费者社会经济属性变量会显著影响消费时空行为,各个商业空间属性变量都在不同程度上影响消费行为在时间和空间上的差异,仅有出行交通方式、出行花费时间2个消费偏好变量会显著影响消费者消费时空间行为。本文结论可以加深对商业中心内消费时空行为影响因素及其作用机制的理解,并为商业网点规划调整、商业中心转型升级提供建议。     

A New Method Searching for Concealed Mineral Resources: Geogas Prospecting Based on Nuclear Analysis and Accumulation Sampling

INTRODUCTIoNThemineralresourcescanbehardlyfoundontheexpo-sureornearthesurfacerecent1y.Itbecomesmoreandmoredifficulttosearchfordeep-seatedresourcesoflargeorsuper-largedeposits,orthedeeppartoftheoldmines.Traditionalmethodsinsomecasesarelesssuccessfulinthesearchformetalmineralresourceshundredsmetersbelow.ExplorationactiQnsmoreandmoredependoncomprehensivemethodsandtechniques-Geogasprospectinghasbeendevelopingasanewandnontraditionalmethodforthisquiteurgenttask.Studyofthegeogasprospectingbased…     

Colonisation of epilithic diatom population of the River Taff, South Wales, U.K.

1. A light and scanning electron microscopic study of the structure of epilithic diatom communities was carried out at two sites on the River Taff, South Wales, an upstream unpolluted site (Site 1) and a downstream polluted site (Site 2). 2. Community structure at the micro-scale revealed that, although communities at both sites were similar in terms of species present (similarity indices ranging between 0.44 and 0.96), they were very different with respect to their physical structure. 3. The traditional approach in studying epilithic diatom communities ignores information relating to community structure. The combination of light and scanning electron microscopy proved to be most useful for studying the epilithic diatom communities. 4. The examination of community succession on stone substrata showed that communities were highly dynamic on a weekly time scale, which suggests that the “age” of a substratum is a very important determinant of the attaching communities. A change from a prostate, two-dimensional community structure to an erect, three-dimensional community structure, and a shift from the dominance of epilithic diatoms to the dominance of epiphytic diatoms were noted. Such a change was more noticed at the polluted downstream site, possibly due to a higher rate of surface pre-conditioning and biofilm production at this site than at the unpolluted upstream site.     

有机改性粘土对铜绿微囊藻的絮凝去除

如何有效的去除富营养化水体中频繁出现的藻华,已成为湖泊环境治理中的一个迫切问题.通过用表面活性剂十六烷基三甲基溴化铵改性的原位沉积物为介质,利用搅拌器和沉积物再悬浮发生装置来研究烷基铵盐改性物质絮凝去除铜绿微囊藻细胞的作用和效果.结果表明,烷基铵盐和粘土的添加量分别为0.3g/L和0.2g/L,搅拌停止30min后,其去除效率达83.9%:在絮凝沉降500min后,水体中藻细胞去除率可达98.9%,较能有效的絮凝沉降藻细胞;同时水体的浊度也有相应的提高.电镜扫描表明这种活性剂形成的网捕包膜作用对藻细胞的沉降起到了重要作用.但烷基铵盐的杀菌作用可能会造成藻细胞内含物向水体释放的风险.     

Morphological and toxicity characteristics of Pseudo-nitzschia pungens strain PP0201-01 isolated from the East China Sea

The morphology and toxicity ofPseudo-nitzschia strain PP0201-01, isolated near the estuary of Changjiang (Yangtze) River in Year 2002 and tentatively identified asPseudo-nitzschia pungens, were studied. The strain was identified morphologically asP. pungens using scanning electronic microscope (SEM). The analytical results of LC-PDA (liquid chromatography with photodiode array detector), LC-MS (liquid chromatography with mass detector), and the toxicity data from mouse bioassay, showed that no domoic acid was produced by the strain. However, the mechanism of domoic acid production byPseudo-nitzschia species is complicated. More works are needed to assess the toxic species and to evaluate the potential risk of amnesic shellfish poisoning (ASP) in China. Supported by the projects of Ministry of Science and Technology (No. 2001CB409704 and No. 2001BA804A20), and the innovation project of the Institute of Oceanology, CAS (No. 200223107).     

LA-ICP-MS in situ analyses of the pyrites in Dongyang gold deposit,Southeast China: Implications to the gold mineralization

The Dongyang gold deposit is a newly discovered epithermal deposit in Fujian Province, Southeast China, along the Circum-Pacific metallogenic belt. Herewith, the authors present mineralogical, scanning electron microscope, and laser ablation inductively coupled clasma mass spectrometry analysis to reveal the relations between Au and Te, As, S, Fe, etc., and discuss the gold precipitation process. The pyrites in this deposit are Fe-deficient, and are enriched in Te and As. The authors infer that As was mainly in form of As-complexes, and Te-Au-Ag inclusions/solid solution also exsits in the Py I. Along with the depletion of Te and As, they were less active chemically in the Py II, and Au may be incorporated into As-rich and Fe-deficient surface sites by chemisorption onto As-rich growth surfaces. Because of the incorporation of new fluid, Te and As became the most active chemically in the Py III, which was the main elements precipitation stage, and As dominantly substituted for S in the lattice of pyrite, due to the more reducing condition. The authors propose Au was in form of invisible gold, and the incorporation of gold can be considered as post-pyrite event, while the Au-bearing minerals were result of post incorporation of gold in arsenian pyrite.     

Radiolarian‐based study on the fabric and the formation process of the Early Cretaceous mélange near Zhongba,Yarlung–Tsangpo Suture Zone,southern Tibet

The Yarlung–Tsangpo Suture Zone (YTSZ), as the southernmost and youngest among the sutures that subdivides the Tibetan Plateau into several east–west trending blocks, marks where the Neo‐Tethys was consumed as the Indian continent moved northward and collided against the Eurasian continent. Mélanges in the YTSZ represent the remnants of the oceanic plate through subduction and collision. Mélanges are characterized by a highly sheared volcanoclastic or siliceous mudstone matrix including blocks of chert, claystone, and basalt. Detailed radiolarian analyses are conducted on the mélange near Zhongba County. Macroscopic, mesoscopic, and microscopic observations are combined in order to elucidate the relationships among age, lithology, and structure of blocks in the mélange. Reconstructed ocean plate stratigraphy includes Lower Jurassic limestone within the chert sequence accumulated at a depth near the CCD (Unit 2), Upper Jurassic thin‐bedded chert interbedded with claystone deposited in the wide ocean basin (Unit 3), and Lower Cretaceous chert with siliceous mudstone (Units 4 and 5), representing the middle parts of ocean plate stratigraphy. The results highlight the fabric of brecciated chert on mesoscopic scale, which is thought to be due to localized overpressure. The formation of mesoscopic and microscopic block‐in‐matrix fabrics in the mélange is proposed for the chert and siliceous mudstone bearing different extents of consolidation and competence during the progressive deformation of accreted sediments at shallow‐level subduction.