磁测中充分采样的重要性

充分采样对于航空磁测或地面磁测(无论是总场测量还是垂向梯度测量)进一步的图象处理和图象增强处理以及磁异常的解释都极为重要.其原因是测得的全部资料都是连续异常场的离散数据集.利用典型的二维岩脉模型来进行理论计算,将场源-探头的距离来代替场源埋深.通过一系列的理论计算和研究分析,作者认为:在大比例尺的高精度航空磁测中,沿测线方向的测点采样间距应小于或等于飞行高度的一半;而测线之间的距离不大于飞行高度.作者最后还引用了两个应用实例.     

航空重磁综合测量在准噶尔油气资源调查中的应用

为满足油气资源调查需要、查明准噶尔盆地基底结构、提供新的油气有利勘探区,中国国土资源航空物探遥感中心在准噶尔盆地中西部开展了航空重磁综合调查。通过项目实施,在国内首次实现了航空重磁综合测量,共采集大比例尺(1:5万)高质量航空重磁数据6.6万测线公里,填补了调查区内大比例尺高精度航空重磁资料的空白,查明了调查区内航空重力场与磁力场特征,为开展基础地质研究和油气资源评价提供了重磁依据,夯实了航空重磁联合测量和综合地质应用研究的基础。     

运五飞机上航磁梯度测量系统的安装与补偿

介绍了在单阀双翼的运五飞机上安装既可进行垂直梯度测量,又可进行水平梯度测量(包括横向和纵向水平梯度测量)的航磁梯度测量系统的方法,初步探讨应用航空地球物理综合测量系统(AADCⅡ)自动航空磁力数字补偿仪的方法,并对补偿结果进行评价。多次实验结果证明了该补偿方法的效果良好。     

冀东南部航磁ΔT低缓异常化极下延特征及其对深部找矿的指导意义

本次研究使用河北省1∶2.5万高精度航空磁测资料。通过对航磁数据进行化极、向下延拓数据处理,对冀东地区3处典型航磁异常不同深度的下延效果进行对比分析,确定磁性体顶板位置。结合钻孔验证结果,讨论了深部矿体在航磁数据向下延拓曲线上的特征,表明了大比例尺高精度航空磁测在寻找深部铁矿上有很大作用,该研究对解决覆盖区深部找矿及危机矿山等问题具有重要意义。     

航磁梯度资料在金矿地质填图和成矿预测中的应用

通过对冀东和冀北地区大比例尺（１：２５０００）航磁梯度资料的分析研究发现，航磁梯度与常规的航磁总场相比，在金矿地质填图中可以更准确地划分不同地层分界、确定火成岩的分布范围以及断裂构造带的平面位置等。总结了金矿床上航磁梯度异常的变化规律。最后，利用包括航磁梯度在内的综合航空物探信息，对冀东渠子地地区进行了金矿预测研究，取得了较好的地质效果。     

大比例尺高精度航磁测量寻找非磁铁矿床的应用实例

阐述了大比例尺高精度航磁测量在寻找非磁铁矿床中的作用;对比分析研究了山东山亭地区几次不同比例尺和测量条件获得的测量结果,并总结了它们的磁异常特征。研究认为大比例尺高精度航磁测量获取信息丰富,由于可识别弱小的磁性地质体,除在原来寻找铁磁性矿床应用外,拓展在其他领域的应用效果显著。     

AS350-B3型直升机硬架航空磁测系统在青藏高原上的应用

为适应在青藏高原高海拔山区开展大比例尺低空航空物探测量工作,满足低飞行高度、高测量精度的要求,通过对比其他机型在机场条件、起飞升限、最大升限、高原机动性能,首次选择使用AS350-B3型直升机并设计制作长杆硬架防振航空磁测系统。对该机型在地面及空中试验进行了磁干扰形式、周期、幅值及衰减规律测试,发现其磁干扰主要由周期为96s幅值约为700nT的脉冲磁干扰、幅值约为300nT的方波磁干扰和周期为1s幅值约为20 nT由螺旋桨转动引起的磁干扰杂波组成,通过把磁探头适当远离飞机发动机及螺旋桨,对硬架系统加装防振部件,再加上磁测设备中的软补偿系统的磁补偿,就可能较好地克服飞机动作及振动引起的磁干扰,从而测量到高质量的磁数据,满足了在高海拔地形切割较大地区作业的要求。     

基于无人直升机平台的航磁系统集成与应用

笔者介绍了无人直升机航磁系统的研发与集成,采用无人直升机作为飞行平台,搭载高精度航空磁测系统,具有低成本、高效率、不受机场跑道限制、可夜航、按设计测线全自主导航飞行等特点。该系统分别完成了磁补偿试验飞行与实际应用工作,补偿精度达到0.046 9 n T,测量成果与测区内以往航磁成果对比,其反映的地磁场特征形态基本一致,验证了该系统的有效性,航磁异常等值线在细节上表现更细致。本系统为大比例尺、高精度、小面积的航磁测量工作提供了一种高效灵活的工作手段。     

无人机航空磁测在滩涂区地质调查的应用试验

对CH-3型无人机航磁测量系统的测控软硬件、差分GPS定位数据同步、多系统适应性改装以及水平横向梯度测量等方面进行了改进完善,在江苏如东县沿岸滩涂区开展了1∶2.5万大比例尺航磁测量实验,验证了改进系统的高精度测控、稳定性等关键性能,在隐伏岩体、推断断裂构造、磁性界面分布等方面取得了较好的应用效果,表明在为滩涂区开发利用提供有效的基础地质和工程地质等方面具有广阔的应用前景。     

新疆塔什库尔干地区铁矿航磁异常特征及找矿潜力

新疆西昆仑地区蕴藏着丰富的矿产资源,通过高精度大比例尺航磁勘查,赞坎、老并等已知铁矿在磁场上特征明显,同时,发现了一批新的大、中型铁矿。重点介绍了新疆塔什库尔干地区已知和新发现铁矿的航磁异常特征,根据高精度大比例尺航空磁测结果的分析,认为新疆塔什库尔干地区蕴含着找铁矿的巨大潜力。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861