云南个旧老厂-卡房花岗岩体成因：锆石U-Pb年代学和岩石地球化学约束

在云南个旧地区发育大量与成矿时空密切相关的侵入岩。个旧东区的老厂-卡房花岗质岩体为一隐伏的花岗岩体,侵入于三叠纪个旧组灰岩和碳酸盐地层中,岩性主要为中细粒黑云母花岗岩,是个旧地区与成矿关系最为密切的花岗岩体之一。岩石的ACNK值大多在1.0以上,属于高钾钙碱性系列岩石;U、Th含量较高,应归属于HHP花岗岩;岩石类型属于S型花岗岩,但经历了高度的分异和演化;n(Rb)/n(Sn)- n(Rb)/n(Ba)与n(CaO)/n(Na2O)-n(Al2O3)/n(TiO2)图解均暗示岩石的源区性质为由粘土岩所派生的岩浆。锆石LA-ICP-MS定年结果表明,老厂-卡房岩体形成于85±0.85Ma,相当于晚白垩世。根据区域地质和花岗岩的地球化学特征,暗示个旧地区燕山晚期处于伸展构造背景。     

松科1井南孔选址、岩心剖面特征与特殊岩性层的分布

松科1井南孔是松辽盆地白垩系科学钻探工程两个钻孔中的一个,位于松辽盆地北部中央坳陷区齐家古龙凹陷敖南鼻状构造的翼部。通过对松科1井南孔嫩二段底部到泉三段顶部连续取心资料的详细描述,建立松科1井南孔岩心剖面,识别出5种常见岩性(泥岩、粉砂质泥岩、泥质粉砂岩、粉砂岩和细砂岩)和8种特殊岩性(白云岩、火山灰、油页岩、灰质泥岩、泥灰岩、重结晶灰岩、介形虫碎屑灰岩和介形虫灰岩)。特殊岩性出现的总层数为172层,总厚度为14.516m,分布在青一段,青二、三段,姚二、三段,嫩一段和嫩二段地层中。对松科1井的精细岩心描述和对特殊岩性的识别是后续研究工作开展的基础。     

汶川大地震（MS 8.0）同震变形作用及其与地质灾害的关系

2008年5月12日发生于四川盆地西部龙门山断裂带的汶川大地震（MS 8.0）波及半个亚洲,震撼整个中国。本文通过地震后的实地调查,对发育在龙门山断裂带上的同震地表破裂带的分布、产状、继承性复活与变形特征,以及同震变形与地震地质灾害的关系等进行了初步总结,分析表明这次汶川大地震(MS 8.0)沿北川-映秀逆冲断裂和安县-灌县逆冲断裂同时发生地表破裂,前者产生以高角度逆冲兼右旋走滑为特征的地表破裂带长约275 km,后者产生以缓倾角逆冲作用为特征的地表破裂带长约80 km。汶川大地震的同震地表破裂带分布具有分段性特征,并与地表破坏程度的分带性有着一定的内在联系,详细研究表明,同震地表破裂带的产状直接影响地表破坏程度和地震地质灾害的强度,汶川大地震（MS 8.0）沿呈高角度陡倾的北川-映秀逆冲断裂发育的同震地表变形所产生的地表破坏程度和地震地质灾害的强度比沿缓倾角的安县-灌县逆冲断裂要强。从各种类型的地震断裂来看,具有垂直运动的逆冲型地震断裂所造成的地表破坏程度和地质灾害强度比具水平运动的走滑型地震断裂要强。因此,汶川大地震发生的破裂过程和同震地表变形与地震地质灾害的关系值得深入研究。     

西天山达巴特矿区火山岩的形成时代、构造背景及对斑岩型矿化的制约

本文通过对西天山地区比较典型的达巴特斑岩铜钼矿床矿区范围内出露的英安岩和花岗斑岩进行了系统的岩石地球化学分析,对流纹斑岩和花岗斑岩中的锆石进行了SHRIMPU—Pb定年研究,分别获得了315．9±5．9Ma和278．7±5．7Ma。岩石化学、微量以及稀土元素特征表明从英安岩到花岗斑岩,岩体具有明显的分异演化特征和很好的继承性。火山岩和次火山岩的精确定年为准确厘定火山岩形成的时限和地球动力学背景提供了依据。结合已有的Re-Os法获得的矿化年龄,表明晚石炭世末-早二叠世初（278．7±5．7Ma）,西天山地区进入板块碰撞-板内伸展阶段,由于深源岩浆侵位,在达巴特矿区形成了由花岗斑岩、流纹斑岩和流纹质角砾熔结凝灰岩组成的椭圆形火山机构,并导致相关矿床的形成。     

Impact of land use covers upon karst processes in a typical Fengcong depression system of Nongla, Guangxi, China

The direction and intensity of karst processes can be deeply affected by soil physical and chemical variations which were resulted from land use. Taking Nongla Fengcong depression area, Mashan County, Guangxi as an example, authors discussed the impact of land use on karst processes based on the data of field limestone tablet. The results showed that the corrosional rates at varied soil depth are quite different. Corrosional rate in woodland and orchard is mostly bigger than 20 mg/a, which is much higher than that in tilled land and shrub. Generally, corrosional rate decreased from orchard, woodland, tilled land, fallow land and shrub successively, in which soil organic matter (OM) and soil pH are two major controlling factors: corrosion process is controlled remarkably by soil OM in woodland and orchard. The higher the organic matter content is and the less the pH value is, the higher the corrosional rate is. Owing to lower organic matter content, the corrosional rate is mainly affected by soil CO₂ in tilled land and shrub.     

Dissolved trace elements and heavy metals in the Danjiangkou Reservoir,China

Concentrations of trace elements and heavy metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Se, Sr, V and Zn) in the Danjiangkou Reservoir, the water source area of the Middle Route of China’s interbasin South to North Water Transfer Project, were analyzed using an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and compared with the national and international standards for drinking water. The results indicated that concentrations of As, Pb, Sb and Se in the Reservoir exceeded the standards and they would pose health risk for residents in the region and the water receiving areas of the interbasin water transfer project. Spatial and temporal variability of the trace elements and heavy metals in the Reservoir implies their mixed sources of natural processing and anthropogenic activities in the upper drainage of the Reservoir. The research results would help develop water resource management and conservation strategy for the interbasin water transfer project.     

Comparison of arsenic concentrations in simultaneously-collected groundwater and aquifer particles from Bangladesh,India, Vietnam,and Nepal

One of the reasons the processes resulting in As release to groundwater in southern Asia remain poorly understood is the high degree of spatial variability of physical and chemical properties in shallow aquifers. In an attempt to overcome this difficulty, a simple device that collects groundwater and sediment as a slurry from precisely the same interval was developed in Bangladesh. Recently published results from Bangladesh and India relying on the needle-sampler are augmented here with new data from 37 intervals of grey aquifer material of likely Holocene age in Vietnam and Nepal. A total of 145 samples of filtered groundwater ranging in depth from 3 to 36 m that were analyzed for As (1–1000 μg/L), Fe (0.01–40 mg/L), Mn (0.2–4 mg/L) and S (0.04–14 mg/L) are compared. The P-extractable (0.01–36 mg/kg) and HCl-extractable As (0.04–36 mg/kg) content of the particulate phase was determined in the same suite of samples, in addition to Fe(II)/Fe ratios (0.2–1.0) in the acid-leachable fraction of the particulate phase. Needle-sampler data from Bangladesh indicated a relationship between dissolved As in groundwater and P-extractable As in the particulate phase that was interpreted as an indication of adsorptive equilibrium, under sufficiently reducing conditions, across 3 orders of magnitude in concentrations according to a distribution coefficient of 4 mL/g. The more recent observations from India, Vietnam and Nepal show groundwater As concentrations that are often an order of magnitude lower at a given level of P-extractable As compared to Bangladesh, even if only the subset of particularly reducing intervals characterized by leachable Fe(II)/Fe >0.5 and dissolved Fe >0.2 mg/L are considered. Without attempting to explain why As appears to be particularly mobile in reducing aquifers of Bangladesh compared to the other regions, the consequences of increasing the distribution coefficient for As between the particulate and dissolved phase to 40 mL/g for the flushing of shallow aquifers of their initial As content are explored.     

运用3DEEMs及荧光偏振方法研究pH、离子强度及浓度效应对腐殖酸荧光光谱特性的影响

利用三维荧光激发.发射光谱(3DEEMs)及荧光偏振法研究了3例腐殖酸和1例湖泊溶解有机物(DOM)在不同腐殖酸浓度、离子强度和pH条件下的荧光光谱特性.实验结果表明,随着浓度增大,各腐殖酸样的荧光强度增大,其中垃圾渗滤液腐殖酸和Pahokee泥炭腐殖酸的荧光峰出现红移.随着浓度进一步增大,腐殖酸的荧光偏振值增大,由此推断在此浓度范围内腐殖酸由于分子间的排斥作用使其构型出现伸展.离子强度增大导致腐殖酸及阿哈湖DOM的荧光强度降低.随着氯化钾(KCI)浓度增大,Fluka腐殖酸的荧光峰A蓝移,荧光峰B的荧光偏振值出现减小,推测是由于静电中和作用使其荧光基团发生卷曲造成的.离子强度对其余腐殖酸样和阿哈湖DOM的其他荧光特性没有明显的影响.总的来说,pH值的变化对腐殖酸和湖泊DOM的荧光特征的影响是很明显的.随着pH值增大,腐殖酸和湖泊DOM的荧光强度增强.而pH值减小时,Fluka腐殖酸和Pahokee泥炭腐殖酸的荧光峰(A峰)蓝移,当pH值降到5时,Fhka腐殖酸的荧光峰突然红移到最大,随后又继续蓝移;垃圾渗滤液腐殖酸和阿哈湖DOM的荧光峰位无明显的漂移.所有样品的荧光偏振值都减小(但阿哈湖DOM的A峰变化不大),但在pHi≤5时又增大,这种现象表明随着pH值降低,腐殖酸和湖泊DOM中有机大分子发生卷曲,但在pH≤5时由于羧基的质子化又以平面伸展构型出现在溶液中.