Are the South and North Liaohe Groups of North China Craton different exotic terranes? Nd isotope constraints

The Liaohe Group is an important Paleoproterozoic stratigraphic unit in the northeastern part of the North China Craton and is traditionally subdivided into the North and South Liaohe Groups. Associated with both the North and South Liaohe Groups are voluminous Paleoproterozoic granitoid rocks, named the Liaoji granitoids. Different tectonic models, including terrane amalgamation, continent–arc collision and rift closure, have been proposed to interpret the tectonic setting and evolution of the North and South Liaohe Groups and associated Liaoji granitoids. At the centre of the controversy between these models is whether or not the North and South Liaohe Groups developed on the same Archean basement. Nd isotopic geochemistry of the Liaoji granitoids provides important constraints on this controversial issue. The Liaoji granitoids associated with the North and South Liaohe Groups display similar ε_Nd values, restricted to a narrow range from 0 to 2, implying that these granitoid rocks were derived from the same or a similar magma source. Moreover, the Liaoji granitoids associated with the North and South Liaohe Groups have similar Nd model ages (T_DM), ranging from 2.4 to 2.6 Ga, suggesting that the protoliths of the Liaoji granitoids associated with both groups may have formed simultaneously, and that the basement rocks underneath the Liaoji granitoids and associated North and South Liaohe Groups belong to the same continental block rather than two different blocks. Combining lithological, structural and geochronological considerations, we interpret the North and South Liaohe Groups as having developed on a single late Archean basement that underwent Paleoproterozoic rifting associated with the intrusion of the Liaoji granitoids and the formation of the Liaohe Group, and closed upon itself in the Paleoproterozoic.     

贵州南部“半边街式”铅锌矿床地质特征及其成因探讨

贵州省南部地区是全国重要的汞、锑资源分布区。2000年由于产于上泥盆统中铅锌矿的陆续发现,贵州省地矿局启动了以铅锌资源评价和成矿规律研究为主的地质工作,目标是总结铅锌矿产出的地质特征和成矿规律。通过三年的研究认为,该区处扬子准地台、华南褶皱带和右江造山带交汇部位,受晚古生代初期发生的陆内裂谷活动影响,产生了一个与桂中台陷相连的大型沉积凹陷区—黔南台陷沉积区,形成了巨厚碳酸盐和碎屑岩沉积,产生了与裂陷盆地边缘同沉积断层活动有关的低温成矿作用,造成了在晚泥盆纪以前的地层中汞、锑、砷、金、铅锌等矿床沿同沉积断层密集分布。本文通过矿床特征总结和矿床成因探讨,建立了准同生沉积成矿作用模式,旨在为该区寻找这类矿床提供参考和借鉴作用。     

Yeosu dinosaur track sites of Korea: The youngest dinosaur track records in Asia

Eighty two dinosaur trackways were newly discovered in Upper Cretaceous lacustrine deposits on islands in the vicinity of Yeosu, Korea. Most dinosaur tracks occur in marginal lake deposits with polygonal desiccation cracks. The dinosaur tracks at the Yeosu site include 65 ornithopod trackways, 16 theropod trackways and one sauropod trackway. The prevalence of ornithopod tracks and the limited occurrence of sauropod tracks at the Yeosu site evidently reflect decreased sauropod diversity in the Upper Cretaceous. All ornithopod trackways represent bipeds, and most of the ornithopod tracks are similar to Caririchnium from other sites of the Korean peninsula. All fossil wood specimens collected in the study area represent conifers (three species of cupressaceous and two species of taxodiaceous conifers, and a new species) except for one, which is a discotyledon. It is thus inferred that the southwestern part of the Korean Peninsula was primarily covered with mesic forests with taxodiaceous trees during the Late Cretaceous. The K–Ar age of the Yeosu tracksite is determined as 81–65 Ma (Camapnian to Maastrichtian). It indicates that the Yeosu track site contains the last records of dinosaurs living in Asia. Consequently, semi-arid palaeoclimatic conditions, together with a large lake as a persistent water source and rich vegetation of gymnosperm trees as food, resulted in the preservation of abundant dinosaur tracks in the Upper Cretaceous on the Korean Peninsula.     

预应力锚索在公路高陡边坡加固整治工程中的应用

预应力锚索锚固技术以其结构合理、工艺灵巧、适应性广、施工速度快、造价低等优势，目前已广泛应用于各工程领域。在桂（林）—柳（州）高速公路高边坡加固工程中采用了该项技术，经过近1年的运转表明，效果良好。对该项工程作了详细讨论，介绍了边坡的地质条件、稳定性分析和设计参数的选取，总结了施工中锚索的造孔、下索、注浆、张拉锁定等设计及施工要点。     

钻孔灌注桩缺陷桩处理实践

在颍河特大桥桩基施工中灌注35号墩-1桩基时，混凝土输送泵出现故障造成浇注中断，桩基检测时发现缺陷，采用旋喷压浆技术进行处理，经检测合格。对采用旋喷压浆处理桩基缺陷的全过程进行了介绍，并对施工中出现的技术问题进行分析。     

桩锚支挡体系在广西寨-任二级公路高边坡治理工程中的应用

(六)寨-(水)任二级公路施工后,滑坡、坍塌、崩塌现象甚多,边坡治理迫在眉睫。桩锚支挡体系是一项主动性加固边坡技术,具结构轻巧、用材合理、施工简单、工期短、费用低等特点。论文通过其在(六)寨-(水)任二级公路K56段高边坡治理工程中的应用,对桩锚支挡体系的设计及施工要点作了介绍。     

黄骅坳陷扣村地区古近系沙三段高分辨层序地层分析

通过利用钻井、测井、地震等多种资料，以黄骅坳陷扣村地区古近系沙三段为例，详细论述了开展高分辨层序地层分析的研究流程、方法．在四级层序格架确定的基础上，叙述了以一般湖泛面和更小级别的岩性和结构层序单元界面的识别与类型的确定．指出通过露头、岩心、测井曲线和高分辨地震信息，可以确定短期旋回界面与超短期旋回界面．根据工区的特点选取主干剖面，建立高分辨率层序地层网络格架对比剖面，开展长、中、短期基准面旋回的分析、高分辨率层序地层的单砂体展布分析及其沉积微相研究．     

电子地图的数据结构与模型

电子地图是集地图表达、数据处理、地图分析为一体的新型地图产品，其数据组织形式直接关系到电子地图的质量与性能。本文对几种数据结构和模型进行了分析、比较，并探讨了它们在电子地图领域的应用前景。     

Combined Digital Photogrammetry and Time-of-Flight Laser Scanning for Monitoring Cliff Evolution

Although cliffs form approximately 75% of the world's coastline, the understanding of the processes through which they evolve remains limited because of a lack of quantitative data on the morphological changes they undergo. In this paper the combination of terrestrial time-of-flight laser scanning with high-resolution digital photogrammetry is examined to generate high-quality data-sets pertaining to the geomorphic processes governing cliff development. The study was undertaken on a section of hard rock cliffs in North Yorkshire, UK, which has been monitored over a 12-month period. High-density, laser-scanned point clouds have been used to produce an accurate representation of these complex surfaces, free from the optical variations that degrade photographic data. These data-sets have been combined with high-resolution photographic monitoring, resampled with the fixed accuracies of the terrestrial laser survey, to generate a new approach to recording the volumetric changes in complex coastal cliffs. This has led to significant improvements in the understanding of the activity patterns of coastal cliffs.     

金刚石工具富铁胎体掺杂稀土的研究

稀土的加入量、加入形态和在混料中的均匀弥散性直接影响热压富铁金刚石复合材料的性能。改进的稀土掺杂工艺，保证了稀土在胎体中的均匀弥散性；通过试验研究了稀土的加入量与富铁胎体的抗弯强度、抗冲击韧性和孔隙率的关系，从而确定了稀土的最优加入量。通过差热分析试验，认为稀土可以改变富铁胎体的热物理特性。