The origin and emplacement of the Lajishankou ophiolite complex in the South Qilian belt: evidences from geological mapping

Many ophiolite complexes like those of Oman and New Caledonia represent fragments of ancient oceanic crust and upper mantle generated at supra‐subduction zone environments and have been obducted onto the adjacent rifted continental margin together with the accretionary complexes and intra‐oceanic arcs. The Lajishan ophiolite complexes in the Qilian orogenic belt along the NE edge of the Tibet‐Qinghai Plateau are one of several ophiolites situated to the south of the Central Qilian block. Our geological mapping and petrological investigations suggest that the Lajishankou ophiolite complex consists of serpentinite, wehrlite, pyroxenite, gabbro, dolerite, and pillow and massive basalts that occur in a series of elongate fault‐bounded slices. An accretionary complex composed mainly of basalt, radiolarian chert, sandstone, mudstone, and mélange lies structurally beneath the ophiolite complex. The Lajishankou ophiolite complex and accretionary complex were emplaced onto the Qingshipo Formation of the Central Qilian block which shows features typical of turbidites deposited in a deep‐water environment of passive continental margin. Our geochemical and geochronological studies indicate that the mafic rocks in the Lajishankou ophiolite complex can be categorized into three distinct groups: massive island arc tholeiites, 509 Ma back‐arc dolerite dykes, and 491 Ma pillow basaltic and dolerite slices that are of seamount origin in a back‐arc basin. The ophiolite and accretionary complex constitute a Cambrian‐early Ordovician trench‐arc system within the South Qilian belt during the early Paleozoic southward subduction of the South Qilian Ocean prior to Early Ordovician obduction of this system onto the Central Qilian block.     

安基山岩体的对流作用和结晶作用

不对称相带的安基山石英闪长玢岩—花岗闪长斑岩侵入体的形成,是浅部岩浆房内对流循环作用的结果,岩浆由顶部向下、边部向里逐渐固结成岩,成岩过程中无明显重力分离。由于岩浆体间歇性上升,早期结晶尚未固结的角闪石英闪长玢岩岩墙,晚期沿着冷却边缘裂隙定位,最后为似斑状花岗闪长岩固结。岩体具水平分带和垂直分带。斜长石的韵律环带反映了在超冷却作用或对流循环过程中发生的组分变化。     

深部煤层CO2注入煤岩力学响应特征及机理研究进展

为揭示CO₂注入煤岩力学响应特征及机理,回顾了CO₂注入煤岩力学性质影响因素、CO₂注入对煤岩大分子-孔隙-裂隙结构改造作用和煤岩力学参数的统计模型、理论模型与智能预测模型.结果表明:CO₂注入煤岩力学性质受控于煤阶、CO₂压力、水分、围压和时间等因素,CO₂注入压力的增高、水的加入及时间的延长均会进一步降低煤岩力学性质,而围压对CO₂注入力学性能弱化具有一定改善作用.CO₂水溶液通过溶胀作用、萃取作用和塑化作用促使煤岩大分子结构重组,通过微晶结构改变、化学溶蚀和非均匀变形改造煤岩孔隙结构,通过化学溶蚀、膨胀应力和化学-应力耦合作用诱发煤岩结构损伤,均不同程度引起煤岩力学性能弱化.在CO₂注入煤岩力学参数预测模型中,类Langmuir模型、广延指数模型和修正的粘聚力模型具有明确的物理意义,而智能预测模型具有更高的预测精度,预测准确度可达99%以上.本次研究为科学评价CO₂-ECBM安全性和促进深部煤层CO₂高效注入奠定了理论基础.      

Microsomal cytochrome P-450 function in fish evaluated with polyclonal and monoclonal antibodies to cytochrome P-450E from scup (Stenotomus chrysops)

Monooxygenase reactions catalyzed by cytochromes P-450 are paramount in the oxidative metabolism of many xenobiotics, determining both the persistence and effects of numerous types of compounds. Immunological probes are proving useful in evaluating the functions of P-450 isozymes in microsomal preparations from many species. The regulation of specific isozymes by endogenous and exogenous factors can also be evaluated with such probes. Here we describe studies on the activities apparently catalyzed by induced P-450 in fish, evaluated with both polyclonal and monoclonal antibodies to cytochrome P-450E, the apparent major β-naphthoflavone(BNF) or methylcholanthrene(MC)-inducible isozyme purified from scup (S. chrysops) liver.     

Imaging the Yellow Sea Bottom Cold Water from multichannel seismic data

The Yellow Sea Bottom Cold Water (YSBCW) is a large cold water mass lying in the deep part of the Yellow Sea during the warm season. We acquired multichannel seismic (MCS) data using an air gun source to image the structure of the YSBCW. The MCS data recorded reflections from sea water. The recognition of these reflections was confirmed by finite-difference seismic modeling in the frequency-domain. The seismic section from MCS data enabled discrimination of water masses distinctly separated by reflecting horizons. The structure of the water masses is fairly consistent with temperature-depth variations obtained using expandable bathythermograph (XBT) casts. The YSBCW is imaged as the lowermost water mass, maximally 40 m thick, that extends as a lens-like form along the sea bottom under the warm mixed layer. The correlation of XBT measurements and the seismic section indicates a rapid decrease in temperature from around 11 to 8 °C in the uppermost part of the YSBCW. A transition zone between the mixed layer and the underlying YSBCW is also defined. This transition zone has fairly uniform thickness of 14–18 m and marks an interval of rapid temperature drop, indicating vigorous thermal mixing. Our study demonstrates that MCS profiling is a useful and reliable tool for imaging fine structures in the shallow Yellow Sea.     

CTL—88B型天气雷达数字天线控制系统电路分析及故障检修

尽管现代化的飞行器性能、机载设备、通讯导航技术得到高度发展,但气象条件仍然是影响飞行和造成飞行事故的重要因素。对低云和雷雨的探测更是航空气象保障的重要内容。本文作者就新建南京禄口国际机场装配的CTL－88B型天气雷达的无线控制系统布线分散、控制保护环节多、运行功率大、故障率相对较高的特点,对如何能快速检测、修理随机故障,确保安全飞行所需的气象探测信息,结合实际工作经验,总结分析了天控系统总体框图、电路检修原理图等。由此,可根据故障现象对电路进行原理分析,测量主要检测点的动、静态参数,诊断故障部件和种类,并提供了常规故障检测的例子,从而极大地提高了排除故障的准确性和时效性,为飞行气象保障工作赢得了时间。     

Numerical Simulation of Roll Vortices in the Convective Boundary Layer

Roll vortices,which often appear when cold air outbreaks over warm ocean surfaces,are an important system for energy and substance exchange between the land surface and atmosphere.Numerical simulations were carried out in the study to simulate roll vortices in the convective boundary layer(CBL).The results indicate,that with proper atmospheric conditions,such as thermal instability in the CBL,stable stratification in the overlying layer and suitable wind shear,and a temperature jump between the two layers in a two-layer atmosphere,convective bands appear after adding initial pulses in the atmosphere.The simulated flow and temperature fields presented convective bands in the horizontal and roll vortices in the crosswind section. The structure of the roll vortices were similar to those observed in the cloud streets,as well as those from analytical solutions.Simulations also showed the influence of depth and instability strength of the CBL, as well as the stratification above the top of the CBL,on the orientation spacing and strength of the roll vortices.The fluxes caused by the convective rolls were also investigated,and should perhaps be taken into account when explaining the surface energy closure gap in the CBL.     

Wavelet entropy-based investigation into the daily precipitation variability in the Yangtze River Delta, China, with rapid urbanizations

In this paper, the daily precipitation data measured at 58 meteorological stations were used, and the spatial and temporal variability of daily precipitation and precipitation extrema in the Yangtze River Delta (YRD) during 1958–2007 was investigated using the indicator of discrete wavelet entropy; then, the urbanization effects were further analyzed. Results indicate that the daily precipitation variability in YRD, especially in the mid YRD with highly urbanized city clusters, is determined by the comprehensive impacts of atmospheric circulation, urbanizations, and the Taihu Lake. Compared with the results in 1958–1985, the variability of daily precipitation and precipitation extrema becomes more complex in 1986–2007, and daily precipitation variability is more complex in the mid YRD relative to the north and south. The precipitation extrema with bigger magnitudes show more complex variability. Urbanizations cause more complexity and fluctuations of daily precipitation in the mid YRD in 1986–2007, reflecting more uncertainty of daily precipitation variability, while the urbanization effects vary with regions and precipitation magnitudes. The variability of precipitation extrema with maximum values is mainly determined by natural atmospheric circulation but has little relationship with urbanizations; however, the variability of those precipitation extrema with general values is determined by both urbanizations and the Taihu Lake in YRD over the last three decades.     

中国东部燕山期火山-岩浆大爆发

中国东部燕山期存在惊天动地的火山＿岩浆大爆发, 形成了７ 条火山岩带, ８ 种岩石系列和组合, 构成了四大火成岩省。在近２０ ×１０６ ａ 内有数百万立方千米的高温岩浆喷出地表, 喷发速率约为０－０３ ｋｍ３／ａ, 对全球气候环境变化和生物灭绝产生巨大影响。火山＿岩浆大爆发与成矿作用大集中是壳幔物质和能量大循环的必然结果。深部地幔柱对岩石圈的突变机制极大地控制了燕山期地质生态的大变革     

Geochronology and Geochemical Characteristics of the Early Mesozoic Tangquan Pluton in Southwestern Fujian and Its Tectonic Implications

The Tangquan granodioritic pluton in Dalian County, southwestern Fujian, China, which extends in a NE direction with an exposed area of about 130 km2, used to be considered a product of Early Cretaceous magmatism. The present study suggests for the first time that the pluton was formed in the Early Jurassic by using multiple methods for isotopic dating, which give zircon U-Pb ages of 186.8 Ma and 179.0 Ma, Rb-Sr isochron age of 162.02±4.5 Ma, and biotite 40Ar/39Ar plateau age of 158.1±0.7 Ma. The cooling rate for the pluton was relatively low (4.76℃/Ma) during the early stage (183-162 Ma) because of the compressional environment. It was emplaced in a higher cooling rate (50℃/Ma) in an extensional environment during the later stage (162-158 Ma). The granodiorites are metaluminous-peraluminous, relatively enriched in Na2O and depleted in K2O, and characteristic of I-type granites of crust-mantle mixed sources. They are moderately enriched in Rb, Th, Hf and LREE, and depleted in Ti, Nb, Ta and Sr, and