勉略构造带新元古代洋盆俯冲作用：来自略阳地区纸房沟岩片火山岩锆石U- Pb年龄和Lu- Hf同位素的证据

纸房沟岩片位于勉略构造带略阳地区。通过细致的岩石学和地球化学研究,将纸房沟岩片内的火山岩分为拉斑玄武岩系列（Ⅰ类）和钙碱性火山岩系列（Ⅱ类）。Ⅰ类火山岩稀土配分曲线左倾,富Na贫P,整体具有N- MORB特点,形成于洋脊构造环境。相比Ⅰ类火山岩,Ⅱ类火山岩具有更高的SiO2(49.02％~61.86％)和K2O(0.32％~1.55％)含量,相对亏损Nb、Ta、P和Ti,形成于陆缘弧构造环境。Ⅱ类火山岩锆石Lu- Hf同位素测试结果显示,εHf(t)值主体为负值,介于-8.01~+0.77,表明其主要为古老地壳物质熔融成因。Ⅱ类火山岩LA- ICP- MS锆石U- Pb测年结果为854±3Ma(MSWD=0.12, n=30)、844±4Ma (MSWD=0.03, n=15),表明纸房沟岩片火山岩结晶时代为新元古代早中期。综合前人成果认为,纸房沟岩片火山岩为新元古代勉略洋盆俯冲的产物,俯冲作用一直持续到800Ma左右,该俯冲过程很可能是对全球性Rodinia超大陆聚合事件的响应。     

基于RS与GIS的广州市城市绿地景观空间分析

以Landsat卫星TM图像为数据源,对广州市区绿地景观进行专题研究.在分析土地利用遥感监测技术流程的基础上,通过实地考察对广州市绿地进行系统分类,提取出所需信息,并结合景观生态学理论对广州市区绿地的空间格局、功能演变进行定量分析,提出广州市区绿地系统未来规划建设的一点意见.通过本研究旨在为RS、GIS和景观生态学领域的结合提供一定的参考,并对生态研究提供一定的借鉴.     

大灰厂断层形变测量结果的地质解译

对大灰厂断层形变测点的36年基线、水准观测资料进行了系统研究，将观测值的变化转换为断层的水平和垂直活动量，并从断层活动方式与所受压应力方向的关系研究了华北地区邢台一唐山地震时段和大同一张北地震时段，以及在八宝山断裂(大灰厂段)上显示的地震前后断层异常活动特征及相应的应力状态。认为对跨断层形变测量资料的分析研究不仅要通过一定的数学处理和统计学分析，更应当从断层活动方式及应力状态进行地质解译，以探索孕震过程中的断层活动信息。     

宁夏吴忠地区北部的浅部结构和隐伏断裂——地震反射剖面结果

应用浅层地震勘探法对宁夏吴忠地区北部的浅部地壳结构和隐伏活动断裂进行研究。结果表明,该区存在2条隐伏断裂,分别为银川主断层南段和新华桥断层。推测银川主断层南段为近SN走向的W倾正断层,断层下盘地层界面一般呈近水平状展布,而在断层上盘,T_Q及其以下的地层界面向断面方向倾伏并显示出逆牵引现象,断层向上错断了第四系内部。钻孔联合地质剖面及浅层地震探测结果共同揭示新华桥断层为一条走向NE,倾向SW的正断层,深、浅地震测线控制的新华桥断层延伸长度9 km左右,向上错断了第四系内部的T_(02)界面。     

Analysis of Paleoseismic Events of Dahuzhuang Trench at the Xiadian Fault

The Xiadian Fault is a very important concealed active fault in the Beijing Plain. It is the seismogenic fault of the Sanhe-Pinggu M_S8.0 earthquake in 1679. The ancient earthquake sequence in the long historical period is of great significance to understand accurately the activity characteristics of the fault and effectively reduce the earthquake disaster risk in Beijing. We have re-interpreted the Dahuzhuang trench, and identified three layers of buried paleosol, six collapsed wedges and one sand liquefaction event. Further, through the comparison with the landmark strata and paleo-earthquake events revealed by other trenches on the fault, an ancient earthquake sequence with a long historical period of the Xiadian Fault was established:since the 31ka, the Xiadian Fault has 11 occurrences of earthquake events (including the 1679 earthquake), and the average recurrence interval is about 2.8ka. The paleo-seismic sequence also shows that there is an ancient earthquake cluster period from 25ka to 15ka, and there are 5 strong earthquakes in the cluster period. The average recurrence interval is about 2.0ka, which reflects the phase difference of the Xiadian Fault activity.     

Structural architecture of Neoproterozoic rifting depression groups in the Tarim Basin and their formation dynamics

The Tarim Basin is the largest, oil-bearing, superimposed basin in the northwest of China. The evolution and tectonic properties of the initial Tarim Basin have been hotly disputed and remain enigmatic. The Neoproterozoic basin is covered by a vast desert and a huge-thickness of sedimentary strata, has experienced multiple tectonic movements, had a low signal to noise ratios(SNRs) of deep seismic reflection data, all of which have posed critical obstacles to research. We analysed four field outcrops, 18 wells distributed throughout the basin, 27 reprocessed seismic reflection profiles with higher SNRs across the basin and many ancillary local 2D and 3D profiles and aeromagnetic data. We found about 20 normal fault-controlled rifting depressions of the Cryogenian and Ediacaran scattered throughout the basin, which developed on the Precambrian metamorphic and crystalline basement. The structural framework is clearly different from that of the overlying Phanerozoic. The rifting depressions consist of mainly half grabens, symmetrical troughs and horst-grabens. From the northeast to southwest of the basin,they are divided into three rifting depression groups with the WNW, ENE, and NW-trends that are mainly controlled by normal faults. The maximum thicknesses of the strata are up to 4100 m. From the Cryogenian to Ediacaran, most of the main inherited faults to active and eventually ceased at the end of the Ediacaran or Early Cambrian, while subsidence centres appeared and migrated eastward along the faults. They revealed that the different parts of the Tarim continental block were in NNE-SSWoriented and NNW-SSE-oriented extensional paleo-stress fields(relative to the present) during the Neoproterozoic, and were accompanied by clockwise shearing. According to the analysis of the activities of syn-sedimentary faults, filling sediments,magmatic events, and coordination with aeromagnetic anomalies, the tectonic properties of the fault depressions are different and are primarily continental rifts or intra-continental fault-controlled basins. The rifting phases mainly occurred from 0.8–0.61 Ga.The formation of the rifting depression was associated with the initial opening of the South Altun-West Kunlun Ocean and the South Tianshan Ocean, which were located at the northern and southern margins of the Tarim Block, respectively, in response to the break-up of the Supercontinent Rodinia and the initial opening of the Proto-Tethys Ocean.     

河川环境规划之景观生态原则应用——以台湾北部淡水河流域为例

河川是一个复杂的生态系统,河川主支干道即为系统中的主要动脉,各种物质循环、能量流动、物种讯息传输,均依赖河川水系为之.但因人类迁入活动及过度利用水资源,干扰了水的自然循环,土壤与微生物的自然演化,生物的迁徙与演替平衡等.且目前河川治理大多以取水、防洪为优先,忽略了景观生态原则在河川中的作用,致使城市与水环境关系日益疏离,物种的栖息地逐渐被破坏.本研究以台湾北部淡水河流域为例,探讨河川流域中之景观生态功能,并将景观生态原则纳入流域治理的综合目标之一,研拟可持续发展的策略.     

三维探地雷达在城市地下管线探测中的应用

城市的扩建、旧城的改造以及水生态建设等都离不开对城市原有地下管线的调查,精准探测地下管线的分布情况是保障管线安全和确保市政工程正常运行的重要工作.为提高城市地下管线探测精度,本文采用三维探地雷达在东莞进行管线探测研究.结果表明,三维探地雷达能显示不同方向、不同埋深、不同类型的地下管线,在城市地下管线探测工作中应用效果显...     

聚球藻病毒研究进展

聚球藻是海洋浮游植物群落的优势组分,是全球碳循环的主要参与者和初级生产力的主要贡献者.聚球藻病毒对聚球藻有较高的致死率,聚球藻病毒对聚球藻的裂解对碳的生物地球化学循环有十分重要的作用.对聚球藻病毒的宿主、分类和生活方式作了简介,综述了聚球藻病毒研究方法、生态分布特征、遗传多样性与宿主的关系及其进展,评述了不同基因标记物在聚球藻病毒分子生态学应用上的优缺点,最后提出了聚球藻病毒的研究展望.旨在为海洋病毒生态学,海洋碳循环的研究提供参考.     

地面和机载多角度观测数据的反照率反演及对MODIS反照率产品的初步验证

MODIS的反照率产品采用半经验的二向性反射核驱动模型算法(AMBRALS),对16天累积观测的多角度遥感数据进行反演。产品的应用需要相关研究的地面观测数据进行验证。主要研究基于地面气象台站用反照率表观测的反照率数据、地面和机载多角度遥感数据通过AMBRALS算法反演得到的反照率,与MODIS相应的地面反照率产品做比较的降尺度验证方法,并提供对MODIS反照率产品的初步验证结果。