U-Pb Zircon and Re-Os Molybdenite Geochronology of theW-Mo Mineralized Region of South Qinling,China, andtheir Tectonic Implications

A W-Mo mineralized region is located along the northern margin of the South Qinling tectonic belt of China. WMo mineralization occurs mainly in Cambrian–Ordovician clastic and carbonate rocks, and the ore bodies are structurally controlled by NW–SE-and NNE–SSW-striking faults. Evidence for magmatism in the area is widespread and is dominated by intermediate–felsic intrusives or apophyses, such as the Dongjiangkou, Yanzhiba, Lanbandeng, and Sihaiping granitic bodies. Quartz-vein-type mineralization and fault-controlled skarn-type mineralization dominate the ore systems, with additional enrichment in residual deposits. At present, there are few or insufficient studies on(1) the age of mineralization,(2) the relationship between intermediate–felsic granite and W-Mo mineralization,(3) the source of ore-forming materials,and(4) the metallogenic and tectonic setting of the mineralized area. In this paper, we present geochronology results for numerous intrusive granitic bodies in the South Qinling tectonic belt. U-Pb zircon geochronology of the Lanbandeng monzogranite and Wangjiaping biotite monzogranite yields ages of 222.7 ± 2.3 and 201.9 ± 1.8 Ma, respectively. In contrast to the Late Triassic age of the Lanbandeng monzogranite, the age of the newly discovered Wangjiaping biotite monzogranite places it at the Triassic–Jurassic boundary. Re-Os molybdenite geochronology on the Qipangou W-Mo deposit yielded a model age of 199.7 ± 3.9 Ma, indicating the deposit formed in the early Yanshanian period of the Early Jurassic. Granitoid intrusions in the mineralized area are characterized by composite granite bodies that crystallized at ca.240–190 Ma. While there were multiple stages of intrusion, most occurred at 210–220 Ma, with waning magmatic activity at 200–190 Ma. The Re-Os age of molybdenite in the region is ca. 200–190 Ma, which may represent a newly discovered period of W-Mo metallogenesis that occurred during the final stages of magmatism. The heat associated with this magmatism drove ore formation and might have provided additional ore-forming components for metallogenesis(represented by the Wangjiaping biotite monzogranite). Ore materials in the mineralized area were derived from mixed crustal and mantle sources. Enrichment of the region occurred during intracontinental orogenesis in the late Indosinian–Yanshanian, subsequent to the main Indosinian collision. At this time, the tectonic environment was dominated by extension and strike-slip motion.     

小动力旋挖钻机用嵌岩短螺旋钻头结构形式的改进

采用小动力无加压旋挖钻机在粒径较大的卵砾石地层和泥页岩地层中进行1500 mm以上大口径钻孔灌注桩施工，由于钻机动力小且不能加压，用常规嵌岩短螺旋钻头钻进出现进尺慢或不进尺现象。通过对河南西峡县宛西制药责任有限公司新厂房桩孔施工过程中出现此种现象的分析和处理，提出了嵌岩短螺旋钻头针对性的改进措施，并取得了良好效果。     

藏南地区中生代硅质岩的地球化学特征及其成因意义

藏南地区中生代硅质岩包括蛇绿岩套硅质岩(与蛇绿岩共生)和非蛇绿岩套硅质岩两大类.本文重点分析日喀则地区彭错林、夏鲁以及泽当地区的罗布莎、江孜盆地宗卓组及四个剖面的硅质岩.其中,彭错林、夏鲁和罗布莎硅质岩与蛇绿岩共生,江孜盆地宗卓组为非蛇绿岩套硅质岩.分析表明:(1)藏南地区硅质岩剖面地球化学特征鲜明,具有一致性和多样性特点;(2)与蛇绿岩共生的彭错林、夏鲁、罗布莎硅质岩普遍具有高Si、高Fe、低Al特征,大部分微量元素相对于克拉克值亏损,稀土元素总量低,经北美页岩标准化后,Ce异常明显或不明显,重稀土相对轻稀土富集.硅质泥岩的∑REE要明显高于硅质岩;(3)非蛇绿岩套宗卓组硅质岩SiO2含量稍低,Al2O3、TiO2则相反.V、Th、Hf、Ta等不相容元素上亏损程度较小,部分样品含量可接近克拉克值.稀土总量相对较高,页岩标准化配分模式上体现为弱Ce正异常,负Eu异常,轻重稀土分异不明显的平坦型曲线图;(4)地球化学特征指示了,藏南地区硅质岩多数具有明显的热水沉积成因属性,同时有正常陆源组分的加入.其中,夏鲁硅质岩的热水沉积地球化学特征较为典型,而宗卓组硅质岩则表现出受陆源物质加入的影响显著的地球化学特点.     

Coupling effect diagnoses of quasi-stationary mesoscale vortex in Guangxi rainstorm process of China

The mesoscale weather system which affected the Guangxi flash-flood-producing rainstorm of China in June 2008 is a quasi-stationary mesoscale vortex. Its genesis and development is closely related to the coupling effects of weather systems in different scales and different latitudes. On the one hand, the coupling of synoptic scale high- and low-level jets provides the environmental conditions for development of vortices and vertical circulations in the mesoscale vortex; On the other hand, the coupling of waves in mid-latitude westerlies and perturbations in low-latitude warm-moist flow under the influence of complex terrain makes the mesoscale vortex circulations strengthened. With the piecewise potential vorticity (PV) inversion method, PV anomalies in different regions are analyzed; also the vortex-vortex interactions and vortex-background flow interactions are diagnosed. Thus, the reasons why the mesoscale is quasi-stationary at first, while developing and deepening later are indicated. Under the condition of coupling effects, the vertical motions accompanied with the mesoscale vortex can be diagnosed with the PV-ω inversion system based on the analysis of quasi-balanced flow.     

Research on Fossil Heritages Protection in Xingwen World Geopark

There are various Permian fossil heritages in Xingwen World Geopark.However,during constructing Geopark in recent years,the fossil heritages have suffered more serious damages,and thus the protection models of the fossil heritage are worth studying.This paper describes the fossil heritages’ types,abundance and preservation of the current status quo in the geopark.It turns out that natural factors and human factors are the main reasons why lead to the destruction of fossil heritages.At last,it puts forward the corresponding measures in order to protect the integrity of fossil heritages in the world geopark.     

UPPER CRUSTAL VELOCITY STRUCTURE AND CONSTRAINING FAULT INTERPRETATION FROM SHUNYI-TANGGU REFRACTION EXPERIMENT DATA

The urban active fault survey is of great significance to improve the development and utilization of urban underground space, the urban resilience, the regional seismic reference modeling, and the natural hazard prevention. The Beijing-Tianjin metropolitan region with the densest population is one of the most developed and most important urban groups, located at the northeastern North China plain. There are several fault systems crossing and converging in this region, and most of the faults are buried. The tectonic setting of the faults is complex from shallow to deep. There are frequent historical earthquakes in this area, which results in higher earthquake risk and geological hazards. There are two seismicity active belts in this area. One is the NE directed earthquake belt located at the east part of the profile in northern Ninghai near the Tangshan earthquake region. The other is located in the Beijing plain in the northwest of the profile and near the southern end of Yanshan fold belt, where the 1679 M8.0 Sanhe-Pinggu earthquake occurred, the largest historical earthquake of this area. Besides, there are some small earthquake activities related to the Xiadian Fault and the Cangdong Fault at the central part of the profile.
The seismic refraction experiment is an efficient approach for urban active fault survey, especially in large- and medium-size cities. This method was widely applied to the urban hazard assessment of Los Angeles. We applied a regularized tomography method to modeling the upper crustal velocity structure from the high-resolution seismic refraction profile data which is across the Beijing-Tianjin metropolitan region. This seismic refraction profile, with 185km in length, 18 chemical explosive shots and 500m observation space, is the profile with densest seismic acquisition in the Beijing-Tianjin metropolitan region up to now. We used the trial-error method to optimize the starting velocity model for the first-arrival traveltime inversion. The multiple scale checker board tests were applied to the tomographic result assessment, which is a non-linear method to quantitatively estimate the inversion results. The resolution of the tomographic model is 2km to 4km through the ray-path coverage when the threshold value is 0.5 and is 4km to 7km through the ray-path coverage when the threshold value is 0.7. The tomographic model reveals a very thick sediment cover on the crystalline basement beneath the Beijing-Tianjin metropolitan region. The P wave velocity of near surface is 1.6km/s. The thickest sediment cover area locates in the Huanghua sag and the Wuqing sag with a thickness of 8km, and the thinnest area is located at the Beijing sag with a thickness of 2km. The thickness of the sediment cover is 4km and 5km in the Cangxian uplift and the Dacang sag, respectively. The depth of crystalline basement and the tectonic features of the geological subunits are related to the extension and rift movement since the Cenozoic, which is the dynamics of formation of the giant basins.
It is difficult to identify a buried fault system, for a tomographic regularization process includes velocity smoothing, and limited by the seismic reflection imaging method, it is more difficult to image the steep fault. Velocity and seismic phase variations usually provide important references that describe the geometry of the faults where there are velocity differences between the two sides of fault. In this paper, we analyzed the structural features of the faults with big velocity difference between the two sides of the fault system using the velocity difference revealed by tomography and the lateral seismic variations in seismograms, and constrained the geometry of the major faults in the study region from near surface to upper crust. Both the Baodi Fault and the Xiadian Fault are very steep with clear velocity difference between their two sides. The seismic refraction phases and the tomographic model indicate that they both cut the crystalline basement and extend to 12km deep. The Baodi Fault is the boundary between the Dachang sag and the Wuqing sag. The Xiadian Fault is a listric fault and a boundary between the Tongxian uplift and the Dachang sag. The tomographic model and the earthquake locations show that the near-vertical Shunyi-Liangxiang Fault, with a certain amount of velocity difference between its two sides, cuts the crystalline basement, and the seismicity on the fault is frequent since Cenozoic. The Shunyi-Liangxiang Fault can be identified deep to 20km according to the seismicity hypocenters.
The dense acquisition seismic refraction is a good approach to construct velocity model of the upper crust and helpful to identify the buried faults where there are velocity differences between their two sides. Our results show that the seismic refraction survey is a useful implement which provides comprehensive references for imaging the fault geometry in urban active fault survey.     

基于MapReduce计算模型的气象资料处理调优试验

云计算技术使用分布式的计算技术实现了并行计算的计算能力和计算效率,解决了单机服务器计算能力低的问题。基于长序列历史资料所计算得出的气候标准值对于气象领域实时业务、准实时业务及科学研究中均具有重要的意义。由于长序列历史资料数据量大、运算逻辑较复杂,在传统单节点计算平台上进行整编计算耗时非常长。该文基于Hadoop分布式计算框架搭建了集群模式的云计算平台,以长序列历史资料作为源数据,基于MapReduce计算模型实现了部分整编算法,提高计算时效。同时,由于数据源本身具有文件个数多、单个文件小等特点,对数据源存储形式及数据文件大小进行改造,分别利用SequenceFile方式及文本文件合并方式对同一种场景进行计算时效对比测试,分别测试了10个文件合并、100个文件合并两种情况,使时效性得到了更大程度的提升。     

马兰冰芯记录的青藏高原中部现代升温变化特征

根据从可可西里地区马兰冰帽钻取的深102.07m冰芯记录中δ¹⁸O的年变化,恢复了青藏高原中部20世纪20年代以来的气候变化.研究表明,青藏高原中部的升温变化与北半球20世纪的升温变化的总体趋势一致,最暖阶段出现在50—80年代早期.期间也出现了几次明显的冷的波动,尤其80年代后期至90年代持续低温,可能与这一时段强盛的夏季风有关.这也表明20世纪末全球急剧升温变化的过程中,某些地区存在气候变冷的波动事件.     

滨海地区不同质地土壤对垃圾渗滤液中氨氮的吸附作用

为了探讨粉砂、粉质粘土、粉土对垃圾渗滤液中NH4+-N的吸附作用,在室内做了吸附实验,实验结果表明,三种土样吸附NH4+-N的等温吸附曲线均符合Langmuir模式,且最大吸附量分别为粉砂1.3 034 ms/g,粉质粘土1.109 mg/g,粉土0.3 439 mS/S.不同土样吸附NH4+-N的能力差异较大,三种土样的吸附顺序为:粉砂>粉质粘土>粉土;三种土样的迟滞因子分别为粉砂27.939,粉质粘土21.782,粉土18.257,说明粉砂和粉质粘土的防污能力较粉土强.     

琼东南盆地高精度层序地层学研究

运用当代层序地层学的原理和方法, 综合分析了地震、测井、岩心等资料, 发现琼东南盆地经历了早期裂陷和晚期坳陷两大发育历程, 相应划分出TejasA和TejasB两个超层序组; 与盆地非海相、海相过渡相、生长断层、缓坡和被动大陆边缘背景演化阶段相匹配, 形成了5个超层序.以不整合及其与之可以对比的整合为三级层序边界, 识别出19个层序, 含5 7个体系域、5 4个以上准层序组、196个以上准层序.在盆地的不同演化阶段, 沉积层序的不同点主要在于低水位体系域包含的沉积体系不同.在恢复古地理环境的基础上, 提炼出有关沉积层序模式.根据可容纳空间分析, 编制了本区海平面升降曲线, 发现陵水中期、梅山早期和莺歌海早期三次大的海泛与全球变化完全合拍.在纵向上, 海进体系域至密集段生烃潜力最强, 空间上以外陆架-大陆坡最好, 其次为滨沼或海陆过渡相.指出了陆架坡折附近的低水位楔和斜坡扇是值得注意的隐蔽圈闭勘探目标.