中扬子区海相沉积盆地性质研究

分析了中扬子区海相沉积盆地基底和层序充填特性;研制了M判别图解,研究了沉积盆地的性质,认为盆地基底具有三分性,盆地层序充填具有阶段性和分区性,沉积盆地主体具有克拉通盆地的特点和性质。     

黑龙江镜泊湖地区全新世玄武岩的地球化学特征及其深部过程探讨

镜泊湖地区全新世玄武岩分布在镜泊湖西北方向的“火山口森林”地区和蛤蟆塘地区。这两个地区相距只有１５ｋｍ,但其玄武质岩石在岩石学上具有明显的区别,前者为碱性橄榄玄武岩,后者为白榴石碱玄岩,并且具有钛角闪石、金云母和歪长石巨晶,而前者则没有这些巨晶。对它们的地球化学特征研究表明,两个地区的玄武夺石虽然均属于偏钠质的碱性玄武岩,但是白榴石碱玄岩相对于碱性橄榄玄武岩总体上具有高的Ａｌ２Ｏ３、Ｎａ２Ｏ、Ｋ２     

不同温压下岩石弹性波速度、衰减及各向异性与组构的关系

结合岩石组构分析 ,阐述了岩石弹性波传播速度和衰减以及它们的各向异性与岩石组构之间的关系。在不同温压条件下对具有很强晶格优选方位的岩石样品的研究表明 ,随着围压的增加 ,波速和Q值均增大 ,但是在相互正交的 3个方向上 (垂直或平行于层理面及线理方向 )增大的速度并不相同 ,这与微裂隙的逐渐闭合密切相关。观测到的波速和Q值的各向异性具有不同的形成机理 ,波速各向异性主要与定向分布的微裂隙和主要矿物的晶格优选方位等构造因素有关 ;高围压下Q值各向异性与速度各向异性正好相反 ,可能是由于定向排列的矿物晶体沿不同方向其边界之间接触程度不同造成的。对岩石组构的研究不仅可以揭示岩体的变形机制、变形的动力学过程及其有关的热力学信息 ,还可以对宏观岩石的各种物理性质 ,尤其是力学特性 ,从微观机理上加以解释。文中特别强调了岩石组构分析对研究岩石物理性质的各向异性具有十分重要的意义。     

赣南地区煤矿分布规律及找煤方向

赣南地区各含煤岩系及煤矿（田）产布特征,具有东西向成片、北北东向成行,受东西向与北北东向推昨合控制的分布规律。因此,深入研究推覆构造系统的特点及其控煤规律,从而确定出煤系“构造窗”、覆于煤系之上的“飞来峰”,甚至辨认出覆于煤系之上的大片外来岩席（包括花岗岩外来岩席）,是确定找煤方向和预测隐伏煤矿（田）的重要途径。     

Spacial organization on the rural settlements in plain areas—taking Pinghu city in Zhejiang of China as an example

1 Spacial Organization Optimizing Theory 1.1 The centeral place theoryThe "centeral place theory" hypothesizes that there is a region: (1) the region is a uniform plain; (2) the motion of economic activities in regions can be carried through in every directions forever; (3) the purchasing power of residents is a successive and uniform distribution; (4) the movement of consumers has rationality in space, namely, proceeding by the shortest distance. The rural settlements as the central place of…     

Gullying and erosion control at archaeological sites in Grand Canyon,Arizona

Gully erosion of cultural sites in Grand Canyon National Park is an urgent management problem that has intensified in recent decades, potentially related to the effects of Glen Canyon Dam. We studied 25 gullies at nine sites in Grand Canyon over the 2002 monsoon–erosion season to better understand the geomorphology of the gully erosion and the effectiveness of erosion‐control structures (ECS) installed by the park under the direction of the Zuni Conservation Program. Field results indicate that Hortonian overland flow leads to concentrated flow in gullies and erosion focused at knickpoints along channels as well as at gully heads. Though groundcover type, soil shear strength and permeability vary systemat‐ically across catchments, gradient and, to a lesser degree, contributing drainage area seem to be the first‐order controls on gully extent, location of new knickpoints, and ECS damage. The installed ECS do reduce erosion relative to reaches without them and initial data suggest woody checkdams are preferable to rock linings, but maintenance is essential because damaged structures can exacerbate erosion. Topographic data from intensive field surveys and detailed photogrammetry provide slope–contributing area data for gully heads that have a trend consistent with previous empirical and theoretical formulations from a variety of landscapes. The same scaling holds below gully heads for knickpoint and ECS topographic data, with threshold coefficients the lowest for gully heads, slightly higher for knickpoints, and notably higher for damaged ECS. These topographic thresholds were used with 10‐cm digital elevation models to create simple predictive models for gully extent and structure damage. The model predictions accounted for the observed gullies but there are also many false‐positives. Purely topographical models are probably inadequate at this scale and application, but models that also parameterize the variable soil properties across sites would be useful for predicting erosion problems and ECS failure. Copyright © 2006 John Wiley & Sons, Ltd.     

The effects of rock uplift and rock resistance on river morphology in a subduction zone forearc,Oregon, USA

Relationships between riverbed morphology, concavity, rock type and rock uplift rate are examined to independently unravel the contribution of along-strike variations in lithology and rates of vertical deformation to the topographic relief of the Oregon coastal mountains. Lithologic control on river profile form is reflected by convexities and knickpoints in a number of longitudinal profiles and by general trends of concavity as a function of lithology. Volcanic and sedimentary rocks are the principal rock types underlying the northern Oregon Coast Ranges (between 46°30′ and 45°N) where mixed bedrock–alluvial channels dominate. Average concavity, θ, is 0·57 in this region. In the alluviated central Oregon Coast Ranges (between 45° and 44°N) values of concavity are, on average, the highest (θ = 0·82). South of 44°N, however, bedrock channels are common and θ = 0·73. Mixed bedrock–alluvial channels characterize rivers in the Klamath Mountains (from 43°N south; θ = 0·64). Rock uplift rates of ≥0·5 mm a⁻¹, mixed bedrock–alluvial channels, and concavities of 0·53–0·70 occur within the northernmost Coast Ranges and Klamath Mountains. For rivers flowing over volcanic rocks θ = 0·53, and θ = 0·72 for reaches crossing sedimentary rocks. Whereas channel type and concavity generally co-vary with lithology along much of the range, rivers between 44·5° and 43°N do not follow these trends. Concavities are generally greater than 0·70, alluvial channels are common, and river profiles lack knickpoints between 44·5° and 44°N, despite the fact that lithology is arguably invariant. Moreover, rock uplift rates in this region vary from low, ≤0·5 mm a⁻¹, to subsidence (<0 mm a⁻¹). These observations are consistent with models of transient river response to a decrease in uplift rate. Conversely, the rivers between 44° and 43°N have similar concavities and flow on the same mapped bedrock unit as the central region, but have bedrock channels and irregular longitudinal profiles, suggesting the river profiles reflect a transient response to an increase in uplift rate. If changes in rock uplift rate explain the differences in river profile form and morphology, it is unlikely that rock uplift and erosion are in steady state in the Oregon coastal mountains. Copyright © 2006 John Wiley & Sons, Ltd.     

Influence of long‐period filter cut‐off on elastic spectral displacements

The effect of the long‐period filter cut‐off, T_c, on elastic spectral displacements is investigated using a strong ground‐motion database from Europe and the Middle East. The relation between the filter and oscillator responses is considered to observe the influence of T_c for both analogue and digital records, and the variations with site classification, magnitude, filter order and viscous damping. Robust statistics are derived using the re‐processed European data to generalize the effects of the long‐period filter cut‐off on maximum oscillator deformation demands as a function of these seismological and structural features. Statistics with a 95% confidence interval are derived to suggest usable period ranges for spectral displacement computations as a function of T_c. The results indicate that the maximum period at which spectral displacements can be confidently calculated depend strongly on the site class, magnitude and filter order. The period range where reliable long‐period information can be extracted from digital accelerograms is twice that of analogue records. Copyright © 2006 John Wiley & Sons, Ltd.     

新疆渭干河灌区水文地质条件变化及排水措施探讨

渭干河灌区的水土环境及水文地质条件在克孜尔水库建成后发生了一定的变化,本文结合灌区12年来的水盐监测资料,对灌区地下水的埋深变化规律、水质演变趋势、灌区的排水效果及目前存在的问题进行了分析与探讨,并为今后灌区排水措施和保持水土环境的良性发展提出了建议.     

鄂尔多斯风沙滩地区土壤凝结水试验研究

鄂尔多斯风沙滩地区,常年干旱少雨,蒸发强烈,地下水资源消耗主要源于表土蒸发.而土壤凝结水的形成与转化又与表土蒸发之间存在着十分密切的关系.作者在内蒙古自治区乌审旗气象局院内,采用自制的笼屉式测渗仪进行土壤凝结水的观测试验研究,测量方法为称重法.并同步观测地表以上50cm处的空气温湿度以及地表和地表以下5cm、10cm、15cm、20cm、30cm、40cm、50cm处的土壤温度.通过试验,初步探明了该区土壤凝结水的形成与转化的基本过程,以及土壤凝结水的转化与气象因素之间的相关关系.