固定铝log(Q/K)图解在温泉中的应用

为探讨常规和固定铝log(Q/K)图解法对温泉系统是否有效 ,采用WATCH程序 ,对江西 3个温度较高的温泉 ,即庐山温泉、汤湖温泉和横泾温泉 ,进行了探测性的研究 .采用常规log(Q/K)图解法计算时 ,由于参加计算的 4个水样的铝含量均未检出 ,计算结果显示只有不含铝的矿物玉髓和方解石相交于温度 1 0 0℃附近 ,热储总体上没有达到平衡 .在采用了固定铝log(Q/K)图解法并同时考虑冷水的稀释作用计算后 ,中低温地热系统中常见的蚀变矿物如浊沸石、纤蛇纹石、萤石和玉髓均显示了较好的收敛性 ,收敛的温度大致在 1 0 0～ 1 4 0℃ .并且上述矿物组合可见于某些温泉的深部钻孔中 ,计算结果与实际地质情况相吻合 .结果表明固定铝log(Q/K)图解法可以恢复温泉系统的热平衡状态     

A meta-analysis of the impacts of forest logging on soil CO_2 efflux

Soil CO_2 efflux, the second largest flux in a forest carbon budget, plays an important role in global carbon cycling. Forest logging is expected to have large effects on soil CO_2 efflux and carbon sequestration in forest ecosystems. However, a comprehensive understanding of soil CO_2 efflux dynamics in response to forest logging remains elusive due to large variability in results obtained across individual studies. Here, we used a meta-analysis approach to synthesize the results of 77 individual field studies to determine the impacts of forest logging on soil CO_2 efflux. Our results reveal that forest logging significantly stimulated soil CO_2 efflux of the growing season by 5.02%. However, averaged across all studies, nonsignificant effect was detected following forest logging. The large variation among forest logging impacts was best explained by forest type, logging type, and time since logging. Soil CO_2 efflux in coniferous forests exhibited a significant increase(4.38%) due to forest logging, while mixed and hardwood forests showed no significant change. Logging type also had a significant effect on soil CO_2 efflux, with thinning increasing soil CO_2 efflux by 12.05%, while clear-cutting decreasing soil CO_2 efflux by 8.63%. The time since logging also had variable effects, with higher soil CO_2 efflux for 2 years after logging, and lower for 3-6 years after logging; when exceeded 6 years, soil CO_2 efflux increased. As significantly negative impacts of forest logging were detected on fine root biomass, the general positive effects on soil CO_2 efflux can be explained by the accelerated decomposition of organic matter as a result of elevated soil temperature and organic substrate quality. Our results demonstrate that forest logging had potentially negative effects on carbon sequestration in forest ecosystems.     

一种链码跟踪与相位验证相结合的直线提取方法

提出了一种链码跟踪与相位验证相结合的直线提取方法。该方法首先针对Canny边缘图提出一种完全细化方法;其次提出一种改进的链码跟踪方法,其步骤包括检测链码端点,建立动态链码主方向确定链码跟踪方向,优先跟踪八邻域内边缘点,八邻域内无边缘点再进行八邻域外边缘点,并采用直线化分析对链码进行动态约束;最后对链码进行直线拟合及相位验证,满足条件输出直线,不满足要求的链码则重新设定端点进行跟踪直线提取。通过多种不同光学图像数据的试验结果分析表明,本文所提出的方法不仅能够精确实现边缘直线信息的拟合,并且能够解决由于白噪声及相位编组所引起的直线断裂问题。     

图割能量驱动的高分辨率遥感影像震害损毁建筑物检测

为充分利用高分辨率遥感影像提供的细节信息,提高震害损毁建筑物检测精度,提出了一种图割框架下融合形状、边缘、角点等多种类型特征的损毁建筑物检测方法。该方法首先利用震前建筑物线划图提取包含单个建筑物的局部影像,用于图割能量函数建模,并分别根据建筑物的位置、形状、边缘以及角点构造能量函数的各约束项。在此基础上,通过最大流/最小割算法求解能量函数最小值,依据最小割能量进行地震前后局部影像中建筑物的相似性度量。最后利用最大期望算法(expectation maximization,EM)求得最小割能量的分类阈值,并根据错分率估值执行后处理以获得最终变化检测结果。采用2011年3月11日东日本大地震前后石卷港的高分辨率遥感影像进行试验,结果表明本文提出的方法能有效检测出损毁建筑物。     

EXPERIMENTAL APPLICATION OF A THINNING SCHEME FOR THE ASSIMILATION OF SURFACE OBSERVATION DATA IN GRAPES-3DVAR

To reduce the spatial correlation of representation error in observations and computational complexity, we propose a thinning scheme that can extract typical observations within a certain range. This scheme is applied to the Global/Regional Assimilation and Prediction System (GRAPES) with three-dimensional variation (3DVAR) to study the effect of the thinning radius on the assimilation results. The assimilation experiments indicate that when the ratio of the model resolution to the observational resolution is 1:3, the simulated results for precipitation are relatively good and have a relatively high equitable threat score (ETS). Moreover, the analysis errors in the temperature and the specific humidity are the smallest, the dependence of the norm gradient vector of the objective function on the number of iterations is slow, gentle, and close to 0, and the minimization results in improved conditions.     

井孔综合成果表自动制作系统

简要介绍了井孔综合成果表自动制作系统－ＷＧＳ的总体设计情况,阐述了ＷＧＳ的结构、功能与特色,并给出了该系统在南通市井孔资料卡片管理上的一个应用实例。该系统采用矢量汉字技术,支持ＤＸＦ和ＰＬＴ两种图形文件存贮格式,支持多种类型打印机,并具有自动选择绘图比例、容错能力强,对硬件和软件要求低等优良性能,是一个专业性、实用性较强的绘图软件。     

华北克拉通地壳结构及动力学机制分析

本文对布设在华北克拉通三个陆块的199个宽频带台站记录的远震数据进行了接收函数计算.利用H-κ迭代方法获得了该区域基岩地区的地壳结构,平滑处理后作为背景结构模型中的基岩地区地壳结构;利用相邻算法对沉积层地区的接收函数进行了波形拟合计算,获得了沉积层结构,平滑后作为背景结构模型中的沉积层结构;结合前人的研究成果,完善了研究区域的背景结构模型.以此模型为基础,对接收函数进行了CCP（Common Conversion Point,共转换点）叠加成像,获得了Moho面成像结果,对比沉积层的成像结果发现：西部陆块中鄂尔多斯块体东部地区地壳厚度较大,约为42 km,泊松比较低,小于0.24,为长英质含量较多的地壳层;位于中部陆块的山西地堑地壳厚度小于鄂尔多斯块体,且变化较大,西侧地壳厚度约为40 km,东侧重力梯度带附近地壳厚度迅速减薄至36 km左右,张家口-怀来-大同一带出现了地壳的局部抬升,地壳厚度等值线基本以北北东方向为主,与构造带方向基本一致,地堑内泊松比约为0.26~0.28,前人对此区域的层析成像研究结果表明太行山隆起和阴山隆起存在壳内低速层,推测为地壳部分熔融以及上地幔物质上涌造成的;东部陆块中渤海湾盆地的地壳厚度较薄,约为32 km,部分地区小于30 km,其中冀中坳陷带地壳厚度最薄,约为28 km,沉积层基底分布与Moho面分布呈镜像对称趋势,沉积层较厚地区的地壳较薄,推测东部陆块在太平洋板块俯冲作用下,存在北西-南东向的拉张作用,使其内发育了大量断陷盆地.     

高分辨率航空影像建筑物垂直边缘线提取技术研究

高分辨率航空影像建筑物垂直边缘线的提取在获取建筑物高度信息和检测建筑物过程中可以发挥重要的作用。分析建筑物垂直边缘线在遥感影像上的特性,在遥感影像边缘检测和细化基础上,利用带约束条件的Hough变换实现建筑物垂直边缘线的提取,通过实验验证该方法的可行性。     

辽北开原地区房木花岗斑岩LA-ICP-MS锆石U-Pb年龄及地球化学特征

研究区位于华北克拉通北缘东段、华北克拉通与兴蒙造山带的交接部位。本文通过对辽北开原地区房木花岗斑岩的岩石学、年代学和地球化学研究,探讨了其形成时代、岩石成因和构造环境,并进一步探讨了华北克拉通东部岩石圈减薄的起始时间。用LA-ICP-MS技术测定了花岗斑岩的锆石U-Pb同位素,获得其锆石²⁰⁶Pb/²³⁸U加权平均年龄为（117±1）Ma,表明花岗斑岩形成于早白垩世。花岗斑岩具有高硅、富碱、贫镁和钙的特征,富集大离子亲石元素（K、Rb）和高场强元素（Th、Ta、Nb）,亏损Sr、Ba、P、Ti元素,稀土配分曲线均呈现右倾海鸥型,具有明显的负Eu异常;显示研究区花岗斑岩为A型（A₁亚型）花岗岩,形成于古太平洋俯冲的后造山伸展环境,其岩浆源于地幔物质上涌而导致的地壳物质重熔。研究区在（156±1）Ma之前,属于挤压造山环境,表明研究区岩石圈减薄时间应处于156~117 Ma之间。     

Ancient deep roots for Mesozoic world-class gold deposits in the north China craton:An integrated genetic perspective

The North China Craton(NCC)hosts some of the world-class gold deposits that formed more than 2 billion years after the major orogenic cycles and cratonization.The diverse models for the genesis of these deposits remain equivocal,and mostly focused on the craton margin examples,although synchronous deposits formed in the interior domains.Here we adopt an integrated geological and geophysical perspective to evaluate the possible factors that contributed to the formation of the major gold deposits in the NCC.In the Archean tectonic framework of the NCC,the locations of the major gold deposits fall within or adjacent to greenstone belts or the margins of micro-continents.In the Paleoproterozoic framework,they are markedly aligned along two major collisional sutures-the Trans North China Orogen and the Jiao-Liao-Ji Belt.Since the Mesozoic intrusions hosting these deposits do not carry adequate signals for the source of gold,we explore the deep roots based on available geophysical data.We show that the gold deposits are preferentially distributed above zones of uplifted MOHO and shallow LAB corresponding to thinned crust and eroded sub-lithospheric mantle,and that the mineralization is located above regions of high heat flow representing mantle upwelling.The NCC was at the center of a multi-convergent regime during the Mesozoic which intensely churned the mantle and significantly en riched it.The geophysical data on Moho and LAB upwarp from the centre towards east of the craton is more consistent with paleo-Pacific slab subduction from the east exerting the dominant control on lithospheric thinning.Based on these results,and together with an evaluation of the geochemical and isotopic features of the Mesozoic magmatic intrusions hosting the gold mineralization,we propose a genetic model that invokes reworking of ancient Au archives preserved in the lower crust and metasomatised upper mantle and which were generated through multiple subduction,underplating and cumulation events associated with cratonization of the NCC as well as the subduction-collision of Yangtze Craton with the NCC.The heat and material input along zones of heterogeneously thinned lithosphere from a rising turbulent mantle triggered by Mesozoic convergent margins surrounding the craton aided in reworking the deep roots of the ancient Au reservoirs,leading to the major gold metallogeny along craton margins as well as in the interior of the NCC.