位场反演计算的场比值法及在宽城地区磁异常解释中的应用

在磁异常的反演计算中,为了避免由于选错了磁性体的形状而产生很大的误差,前人已研究了多种所谓自动反演的计算方法.与传统的方法不同,用这些方法,可以同时确定磁性体的几何形状和埋藏深度等参数.但是前人研究的方法需要计算磁异常的三阶导数,因此所受高频噪声干扰十分严重,以至于影响到计算结果的可靠性.因此很难用到实际资料处理中.本文提出的场比值法可以同时确定磁性体的形状和埋藏深度.场比值法通过场比值field-ratio来确定磁性体的形状,field-ratio的物理含义与Euler反褶积公式中的形状因子类似.场比值法的优点是在反演计算中只需要计算磁异常的一、二阶导数,因此比前人的方法受高频随机干扰小,可以用于实际资料的处理中.模型实验证明了场比值法的正确性,在河北省宽城地区用场比值法对磁异常反演计算,展示了方法的实用性.     

航放异常解释用Z量板的水泥模型验证

对航放异常矩形反演使用的理论Z量板进行了水泥板模型验证，解决了在航放实测条件下难以验证以及如何消除验证模型对γ射线的等效空气吸收系数与空气本身对γ射线的吸收系数不同的影响等问题。验证结果表明，该量板是正确的，可用的。     

阿尔金山东端花岗片麻岩中3.6Ga锆石的地质意义

本文报道首次用单颗粒锆石U Pb同位素测年技术在我国西北阿尔金山东端古老花岗片麻岩中发现36 0 5± 43Ma的锆石。这是塔里木地块存在始太古代基底的重要证据 ,对研究该地区的地壳演化及其与我国东部和全球其他古老地块的对比研究具有重要的意义。     

Timing and magnitude of displacement on the Altyn Tagh fault: constraints from stratigraphic correlation of adjoining Tarim and Qaidam basins, NW China

The Altyn Tagh fault plays an important role in growth of the north-western Tibetan plateau, but the timing of its inception and magnitude of left-lateral displacement are not well constrained. This study provides new independent constraints by correlating stratigraphic development and spatial distribution of the neighbouring Tarim and Qaidam basins. It is shown that the Tarim and Qaidam basins experienced quite similar stratigraphic and sedimentary evolution from late Sinian to early Palaeogene times. This fact indicates that the Tarim and Qaidam basins were a single block, at least until Oligocene time, which was then offset by the Altyn Tagh fault. Early Palaeozoic and Late Triassic suture zones within the East and West Kunlun and pinch-outs of Mesozoic strata are chosen as piercing lines. Restoration of these lines gives total offset estimates of ˜ 350–400 km across the south-western and central segments of the Altyn Tagh fault.     

节水灌溉与农业面源污染控制研究--以新疆焉耆盆地为例

针对我国北方农业面源污染面积大、分布广、控制难的问题，通过分析新疆焉耆盆地水资源利用现状、潜水位动态、农田排水特征，认为大水漫灌不仅浪费水资源，造成肥料流失，降低产量，而且污染水体，导致土壤次生盐渍化；提出了推广节水灌溉、合理开发利用水资源、控制农业面源污染、综合治理环境的有效途径。     

辽河坳陷西部凹陷南段古近系沙河街组致密砂岩特征与成因机制*

渤海湾盆地辽河坳陷西部凹陷南段古近系沙河街组中发现了低产油气流和工业油气流,储集层具有低—特低孔隙度、特低—超低渗透率、低压的特征,属于典型的致密砂岩储集层。应用大量的薄片、扫描电镜、粒度分析、压汞和物性等测试资料,研究了致密砂岩的微观特征,探讨了致密砂岩的形成机理。研究结果表明,致密砂岩(孔隙度小于10.0%)大多发育在凹陷区;矿物成分、粒度、分选、磨圆等沉积学参数与致密砂岩的形成关系不大;致密砂岩的孔隙类型主要为次生孔隙,孔隙结构整体上具有中孔径、微细喉以及喉道分选不均匀等特征;机械压实作用和胶结作用导致了致密砂岩的形成,该致密砂岩属于次生型致密砂岩。     

TRMM卫星降水数据在小尺度流域的评估与应用

选取史灌河流域上游黄泥庄站以上集水区域为研究流域,以地面站点观测为基准数据,评估TRMM 3B42V7版本卫星降水数据的精度,并采用上述两种降水数据驱动栅格型新安江模型,模拟黄泥庄站日径流和月径流过程。结果表明:2001~2010年TRMM 3B42V7降水数据与雨量站数据累积量的偏差不大,仅为1.71%,但相关系数较低,采用TRMM降水数据模拟的日径流能基本再现黄泥庄站的日径流过程,但对洪峰的模拟精度较低;TRMM月降水数据精度较高,相关系数为0.96,能够较为精确地模拟黄泥庄站的月径流过程。     

Aerodynamic Characteristics of the Crest with Membrane Attachment on Cretaceous Pterodactyloid Nyctosaurus

The Nyctosaurus specimen KJ1 was reconstructed under the hypothesis that there is a membrane attached to the crest; the so-called headsail crest. The aerodynamic forces and moment acting on the headsail crest were analyzed. It was shown that KJ1 might adjust the angle of the headsail crest relative to the air current as one way to generate thrust (one of the aerodynamic forces, used to overcome body drag in forward flight) and that the magnitude of the thrust and moment could vary with the gesture angle and the relative location between the aerodynamic center of the headsail crest and body’s center of gravity. Three scenarios were tested for comparison: the crest with membrane attachment, the crest without membrane attachment and the absence of a cranial crest. It was shown that the aerodynamic characteristics (increasing, maintaining and decreasing thrusts and moment) would have almost disappear in flight for the crest without membrane attachment and was non-existent without the cranial crest. It is suggested from aerodynamics evidence alone that Nyctosaurus specimen KJ1 had a membrane attached to the crest and used this reconstructed form for auxiliary flight control.     

Cenozoic Exhumation and Thrusting in the Northern Qilian Shan, Northeastern Margin of the Tibetan Plateau: Constraints from Sedimentological and Apatite Fission-Track Data

Abstract: The Qilian Shan lies along the northeastern edge of the Tibetan Plateau. To constrain its deformation history, we conducted integrated research on Mesozoic–Cenozoic stratigraphic sections in the Jiuxi Basin immediately north of the mountain range. Paleocurrent measurements, sandstone compositional data, and facies analysis of Cenozoic stratigraphic sections suggest that the Jiuxi Basin received sediments from the Altyn Tagh Range in the northwest, initially in the Oligocene (~33 Ma), depositing the Huoshaogou Formation in the northern part of the basin. Later, the source area of the Jiuxi Basin changed to the Qilian Shan in the south during Late Oligocene (~27 Ma), which led to the deposition of the Baiyanghe Formation. We suggest that uplift of the northern Qilian Shan induced by thrusting began no later than the Late Oligocene. Fission-track analysis of apatite from the Qilian Shan yields further information about the deformation history of the northern Qilain Shan and the Jiuxi Basin. It shows that a period of rapid cooling, interpreted as exhumation, initiated in the Oligocene. We suggest that this exhumation marked the initial uplift of the Qilian Shan resulting from the India–Asia collision.