Fault geometrical model of Dujiangyan section in Longmenshan fault zone

The focal mechanism solution on the seismic fault plane can reflect the geometric and kinematic characteristics of faults, and it is an important way to further study the fine structure of fault plane. From the focal mechanism solution of the earthquakes around the Dujiangyan fault in Longmenshan fault zone, we derived the average dip angle of Dujiangyan fault is 45.1° based on the seismic moment tensor theory. In order to refine the fault geometry structure, this paper decomposed it into multiple sub-fault planes along the length and width of the fault plane and forms a number of models A13, B13, A23 a, A23 b, A23 c, B23 a,B23 b and B23 c, then calculated the sub-fault's dip of each model. In order to clarify exactly which one of the fault models is closest to the real fault model, the fault slip was carried out for each model in turn, then compared the surface displacement of each model with GPS observations. The results show that B23 c model with high dip in shallow and small dip in deep is the best model, the lengths of each subfault of Dujiangyan fault from south to north are 33 km, 21 km and 46 km, respectively. When the depth of the fault bottom is about 11 km, the dip angles are 70.56°, 67.41° and 45.55°.When the depth of the fault bottom is about 30 km, The fault dip angles are 44.55°, 29.18° and 44.25°.     

博斯腾湖湖泊沉积物光释光年代测量*

使用光释光年代学的单片再生法测量了博斯腾湖沉积剖面中碳酸盐泥及粉砂质泥底部的浅湖相灰色粉细砂和风成沙的年龄,对剖面上部碳酸盐层中陆生植物残体进行了AMS ¹⁴ C测年。通过不同测片的等效剂量(D_e)值的分布状况评价了样品的晒褪程度,选择不随灵敏度校正后的自然释光信号变化的相对集中的等效剂量(D_e)值计算了样品的埋藏年龄。通过这些年龄结果的对比,发现石英矿物的OSL年龄和AMS ¹⁴ C年龄在地层上是一致的,表明尽管在浅湖相细砂中存在不完全晒褪,但根据相对较小而集中的D_e值计算得到的年龄结果是可靠的。这些年龄结果和地层资料揭示末次冰消期以来至早全新世,博斯腾湖处于无水干盆地向深水湖泊转化的浅水湖泊状态,现代深水博斯腾湖大约形成于距今8ka前后。     

Duplex equilibria of Ural circulation anomalies

Atmospheric circulation anomalies over the Ural Mountains are crucial indicators of the anomalous downstream weather and climate over East Asia. Here, we provide a new perspective on the mechanism of Ural circulation anomalies. We use a simple theoretical model to determine that the relationship between the solar forcing and three Ural circulation patterns, namely, neutral type, trough anomaly and ridge anomaly, is a nonlinear relationship following the supercritical pitchfork bifurcation theory. The theory predicts that when the total solar irradiance (TSI) is below a critical value, trough and ridge anomalies represent duplex equilibria and are equally likely to occur at the same TSI. Based on 180 winter months record, we have estimated the bidimensional probability density of TSI and the monthly mean geopotential height at 500 hPa or zonal wind at 850 hPa over the Ural Mountains. Results show that Sc = 1360.9 W m−2 is a critical value of TSI, the neutral type pattern is the single circulation regime when TSI > Sc, whereas trough and ridge anomaly patterns are duplex circulation regimes when TSI < Sc. Besides, when TSI < Sc, during the same TSI range, trough and ridge anomaly events occur at nearly the same frequencies. These results generally agree with the theoretical model. We demonstrate that trough and ridge anomalies, as duplex equilibria, result from the large-scale zonal flow interacting with the Ural Mountains. Low TSI tends to strengthen the large-scale zonal flow over the Ural Mountains, hence inducing either a trough anomaly or ridge anomaly.     

硅藻土的热谱特征

对广东省海康县等国内外２３个硅藻土样品进行了ＤＴＡ、ＴＧ分析。研究结果：海康县卜昌、美国和日本硅藻土呈现了典型的蛋白石ＤＴＡ曲线和Ｘ射线衍射谱，说明样品纯度较高；徐疗县峙头、九亩和云南等地的硅藻土除了蛋白石的ＤＴＡ和Ｘ射线衍射谱外，还含有较多数量的伊利石、蒙脱石和高岭石。取自九２和田洋硅藻土矿床钻孔样品的ＤＴＡ曲线含有较多数量的有机持。根据ＴＧ曲线对不同埋深硅藻土中有机质含量计算表明，有机质含量与     

应用撑柱粘土矿物治理赤潮灾害的初步研究

最初,人们利用蒙皂石层间阳离子的可交换性,将水合羟基-聚合金属离子插入到层间 ,并进一步加热脱羟.脱羟基后在层间域形成柱状金属氧化物群,从而将蒙皂石层间撑开,这就是所谓的撑柱蒙皂石.它在保持粘土层状结构的同时,在主客体物质协同作用下,还获得一些新的物化性质或功能.现在关于撑柱的概念已有所扩展,凡是向粘土层间插入有机阳离子或无机-有机阳离子的都称之为撑柱.     

云南乐红铅锌矿床氧化带中异极矿的矿物学特征及其意义

云南乐红铅锌矿床氧化带十分发育,呈细脉或葡萄状产于氧化矿石中的白色矿物曾被认为是菱锌矿,笔者对该矿物作了物理、光学性质,化学发,Ｘ射线衍射,红外光谱及失重和差热分析研究,确定其为异极矿。其晶体化学式为Ｚｎ３．９８（Ｓｉ２．０１Ａｌ０．０１）２．０２Ｏ７（ＯＨ）２．０３．０．８８Ｈ２Ｏ晶胞参数ａ＝０．８３８０（４）ｎｍ,ｂ＝１．０７１８（７）ｎｍ,ｃ＝０．５１２５（６）ｎｍ。对异极矿矿物学特征的全面     

江苏某材料厂周边农田土壤钼污染特征及农作物健康风险评价（84）

为了解江苏某材料厂金属冶炼活动引发的重金属污染风险,采集周围农田土壤、小麦和水稻籽实样品,确定Mo含量及其在土壤中的形态,采用地质累积指数和富集因子指标评价土壤中钼的污染风险,采用健康风险指数评价小麦、稻米中Mo的健康风险。结果表明,农田土壤中Mo含量在0.50～63.2 mg/kg之间,其平均值5.70 mg/kg远高于全省平均值0.65 mg/kg,表层土壤出现了中度—高度富集,近70%的样点受到不同程度的钼污染,污染范围距该厂300 m,污染深度>1.5 m。土壤中的Mo具有较高的生物有效性,在小麦、水稻籽实中显著富集,主要与土壤具有较高的全Mo含量以及土壤呈碱性有关。基于EPA的健康风险评估方法,食用当地稻米、小麦会产生较大的健康风险。     

福州平安大厦深基坑支护设计与施工

深基坑支护设计与施工是当前城市高层、超高层建筑突显的技术难题。通过工程实例,从设计方案的选择到施工、监测,提供了有益的经验。     

胶东内生金矿成矿期次和成矿时代的讨论

胶东地区内生金矿的成矿溶液是深溶岩浆连续分异演化而成.成岩成矿作用产生于同一个地质时代,并可分为包括岩浆岩体、脉岩、矿床及其诸成矿阶段在内的早晚两期成矿系列.早期的内生金矿为主生金矿期.晚期为共生—伴生金矿期.早期成矿系列生成时代于156～136Ma之间,晚期为124～100Ma.