平行路段模式识别与简化初探

道路网模式中的平行路段作为一种局部模式,其识别与简化是地图综合研究的重要内容。本文在分析平行路段产生的原因和常见形态后,给出一种利于简化的平行路段分类方法,并提出基于平头缓冲区搜寻备选平行路段进而利用平行性测度判断路段是否平行的方法。在此基础上,针对3类平行路段分别提出对应的几何化简与连通关系简化方法。实验结果表明,该识别与简化方法能够对路网模式中的平行路段进行有效地综合,具有一定的实用价值,对进一步研究具有参考价值。     

Paleoenvironmental conditions across the Cretaceous–Paleogene transition at the Apennines sections (Italy): An integrated geochemical and ichnological approach

Two distal Cretaceous–Paleogene (K/Pg) boundary sections in the Central Apennine region (Italy) have been studied: Bottaccione Gorge and Contessa Highway. Geochemical and carbon isotope analyses on the infilling of trace fossils and on the host sedimentary rocks were performed to determine paleoenvironmental conditions during the Cretaceous–Paleogene transition. Major and trace element contents were measured in a 63 cm-thick interval at Bottaccione Gorge (from 22 cm below to 41 cm above the K/Pg boundary) and in a 72 cm-thick interval at Contessa Highway (from 43 cm below to 29 cm above the K/Pg boundary). Even though the K/Pg ejecta layer is now depleted at these sections due to continuous oversampling, the uppermost Maastrichtian and lowermost Danian deposits record the paleoenvironmental conditions prior to and after the K/Pg event. We used redox-sensitive element ratios (V/Al, Cr/Al, Co/Al, Ni/Al Cu/Al, Zn/Al, Mo/Al Pb/Al and U/Mo) and detrital element ratios (K/Al, Rb/Al, Zr/Al and ƩREE/Al) as proxies of certain environmental parameters, used for paleoenvironmental reconstruction. In general, similar values for elemental ratios are registered within Maastrichtian and Danian deposits, which supports similar paleoenvironmental conditions prior to and after the K/Pg event as well as the rapid reestablishment of the pre-impact conditions (i.e., oxygenation, nutrient availability, and/or sedimentary input). An enrichment in certain redox-sensitive elements above the K/Pg at the Bottaccione Gorge section suggests lower oxygenation, as also evidenced by the tracemaker community. Carbon isotope composition data from the infilling material of trace fossils furthermore reveals values similar to those of the host rocks at the corresponding depth, which supports an active infilling by nearly contemporaneous bioturbation during sediment deposition.     

资源型城市工业产业发展的实证研究--以铜川市为例

资源型城市是我国城市中重要的类型之一。目前,这类城市工业产业的发展遇到了前所未有的困难,直接影响到资源型城市的可持续发展,文章以铜川市为例,论述了工业产业发展现状和原因,提出了铜川市工业产业发展的对策。     

Mechanical quality of bedrock with increasing ductile deformation

Most of the rocks in Precambrian shield areas have experienced a complex structural and metamorphic evolution, processes which have a strong influence on bedrock quality. The properties vary on both a local and a regional scale. It is highly beneficial to know the variations in detail when exploiting the rocks for industrial purposes. The main objective of the investigation was to study the variation of rock mechanical properties in an originally more or less isotropic rock at various stages of ductile deformation. The rocks investigated were Paleoproterozoic and with ages of ca. 1.80-1.88 Ga, and the areas chosen for sampling were situated north-east of Lake Vänern (Kristinehamn; 10 samples), south of the city of Eskilstuna, South Central Sweden (5 samples) and south of Ödeshög, near Lake Vättern in southern Sweden (7 samples). The 12 samples from the latter two areas are described in this investigation, while the 10 samples from Kristinehamn have been published earlier (Göransson et al., 2004). A comprehensive study of various parameters of importance for bedrock quality has been performed on all samples, e.g. studded tyre test (STT) and Los Angeles test (LA), uniaxial compressive strength (UCS), ultrasonic velocity, perimeter measurements of mineral phases, and petrographic and chemical analyses. The weakly deformed and massive (more or less isotropic) rocks show a tendency towards better properties of abrasion (STT) than the strongly deformed rocks and this can also be said for UCS, reflecting the greater ability of rocks to split along foliation planes. This is not entirely unambiguous, as the more deformed rocks, such as the mylonites, may have varying properties. This depends on the combined effects of, e.g. grain size, recrystallisation and foliation. However, the brittleness (LA) shows somewhat better values with increased deformation. This may depend on higher amounts of dark minerals, as their existence does not affect this test as much as in the case of abrasion tests. The perimeter values of the mineral phases display generally higher values, i.e. grain boundaries for the more strongly deformed rocks are more complicated. However, the values for the investigated mylonites may vary between low and high. The lower value may be due to dynamic recrystallisation and the creation of triple points (static recrystallisation) making the rock weaker. Besides, the development of a strong foliation may decrease rock strength despite the usually finer grain size. The results show that it is extremely important to consider all possible variations of bedrock before classification and exploitation, as the bedrock material in fact is highly heterogeneous.     

Determination of Multiple Trace Element Compositions in Thin (> 30 μm) Layers of NIST SRM 614 and 616 Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)

To understand and/or avoid small-scale chemical heterogeneities within geological materials prepared as normal thin sections, in situ multiple trace element determination coupled with the simultaneous microscopic observation of the sample during analysis is preferable. We have examined fifty trace elements in thin (< 30 μm) layers of the NIST SRM 614 and 616 glass reference materials by LA-ICP-MS using different pit diameters and internal standard elements (Ca and Si). Compositional heterogeneities of Tl, Bi, As and Cd were found in NIST SRM 614 and 616 at the spatial resolution of ca. 10 0 μm. Except for these elements, the RSDs of six determinations for most elements were better than 10% in NIST SRM 614 when ablation diameters were < 50 μm. The measured concentrations for most elements in NIST SRM 614 and 616 agree with previous values in the literature at the 95% confidence level with the exception of W and Bi. New LA-ICP-MS data for K, As and Cd are also reported. The results support the view that the latest LA-ICP-MS is a powerful and flexible analytical technique for the determination of multiple ultra-trace element compositions in geological materials prepared as normal thin sections of the type that has been used for polarising optical microscopic observations since the end of the 19th century.     

地貌及等高线表示的分解定理与表现定理

随着计算机制图和GIS的迅速发展，对于有着广泛应用的地貌形态特征问题，提出了进一步加以科学、系统、深入定量研究的迫切要求，以便获得更科学、合理的应用。作为一个系列研究的开始，首先要解决用2维空间的等高线表示3维空问地貌形态的科学性这一问题。为此，文中引入了地貌截影及截地貌的概念，通过地貌分解定理与表现定理的证明，以及等高线、地貌截影和截地貌三者之间的等价关系的论述，最终从数学上解决了上述基本问题，为今后的深入研究奠定了基础。     

土耳其贝帕扎里天然碱矿钻井工程MWD实地校核

土耳其贝帕扎里天然碱矿采卤工程是目前世界范围内采用对接井水溶开采方法进行采矿的最大规模的天然碱采矿工程。在对接井施工过程中，由于出现了地磁变化异常和地质条件变化，致使MWD导向系统出现了一定偏差。为减少仪器偏差，设计并对仪器进行了实地校核。校核结果表明，探管的安装条件对其数据精度有较大的影响。其校核结果被应用于实际生产中，起到了良好的指导作用。     

远震数据显示贝加尔裂谷带北穆伊斯克(Severomuysk)段地壳和上地幔的精细结构

通过贝加尔裂谷系统北穆伊斯克(Severomuysk)段的密集地震台站线性网络获得的远距离强震记录,并利用P波接收函数技术,揭示了地壳和上地幔顶部的复杂分层块状结构。横波速度的分布表明构成北穆伊斯克地壳的地块具有不同性质。这些地块的西部聚散和地壳下部的分层证实了该地区隆起的堆积-碰撞起源。位于西伯利亚克拉通变薄的倾斜边缘上的北穆伊斯克段解释了该地区地壳碰撞效应的强度。2015年地震的震中深度与Muyakan 凹陷地壳上部的明显速度差异存在令人信服的相关性。     

辽宁省海城市牌楼镇发达菱镁矿、滑石矿特征

本文叙述了辽宁省海城市牌楼镇发达菱镁矿、滑石矿矿区地层、构造、赋矿层位等控矿因素,对区内菱镁矿、滑石矿矿体特征、矿石矿物组成、矿石化学成分、质量、品级等进行了研究分析,确定该矿床成因为区域沉积变质热液交代型矿床。     

无建槽直井的定向中靶作业

传统的施工水平对接井的连通工艺多采用造腔溶通或压力式连通,由于其施工周期长、成本高等缺点正在被以精确连通仪器引导连通工艺所取代。以江苏淮安SY4井组为例,介绍了采用具有自主知识产权的“慧磁”钻进中靶导向系统,与一口没有建槽的直井进行定向中靶作业。由于存在直井井斜数据误差大、钻具磁化、溶腔半径极小等困难,进行了3次中靶作业后最终成功连通。