1766年以来永定河汛期径流量与太平洋年代际振荡

以清代永定河芦沟桥志桩尺寸记录为骨干资料,结合近现代器测水文资料,使用分段建模的方法恢复了1766-2004年永定河芦沟桥断面的汛期径流量序列,序列表明永定河径流量在逐年尺度上具有极大的不稳定性,但其洪峰规模自19世纪以来不断减小,19世纪中期与20世纪初期是最为明显的丰水时段,而1920年代后径流量便明显萎缩,枯水期一直延续至现代。进入1920年代后,流量变化在18世纪后期至19世纪存在的30年准周期消失,水量变化呈现无周期特征。与太平洋年代际振荡指标PDO的比对发现,两者在30-40年尺度上具有明显的反相关关系,天然状态下,太平洋温度升高对应于永定河流域较为干旱的时段。海温异常造成的季风强度变化会导致华北地区降雨格局出现变化,进而影响到永定河芦沟桥以上河段的汛期水量,表明处于季风区北部边缘的永定河水系对于太平洋海温变动具有更大的敏感性。     

1908-1909年克拉克探险队在黄土高原地区的考察——基于《穿越陕甘》的探讨

1908-1909年,美国克拉克探险队在黄土高原腹地的晋、陕、甘等省区进行了480余天的综合科学考察,行程3200余公里,沿途进行动物标本收集、地图测绘、气象观测等活动,对途经地区的气象、地貌、水文、植被、动物、城镇、商贸、人口、交通等内容进行了广泛调查和记述,是清代后期西方人对黄土高原地区自然和人文地理状况最为系统的一次考察。本文以《穿越陕甘》的记述为中心,结合相关英文文献,重点阐述克拉克探险队的组建过程、行经路线、调查方法、考察内容等,并与同一时期其他欧美探险队进行比较,以客观评价克拉克探险队的考察收获。     

利用3D虚拟建模技术再现考古遗址文化场景

基于现有3D可视化技术,分别介绍了3D图形库接口、XMI技术与组件、VRML、虚拟现实技术等可以实现考古遗址文化场景的方法,并从3D建模的角度比较了各种方法的特点,探讨了较为实用的考古遗址3D重建途径.     

清代黄土高原地区城镇书院的时空分布与选址特征

清代城镇书院已比较普遍地发展起来,但城镇书院在各地的发展却经历了不同的时空演变过程。本文通过对黄土高原地区不同级别城镇书院的考察,详细地揭示了不同级别城镇书院的时空演变过程及其特征。府县级城镇仿效省会设立书院的实践主要在乾隆年间才出现,城镇书院的发展总体上由区域东南部向西北部推广,乾隆时期出现发展高峰,发展重心向黄河以西转移。城镇书院时空变化特征显著。书院选址以城内为主,空间上体现了偏重东部和东南部的观念。     

论我国黄土高原地区生态环境演化特点与可持续发展对策

我国黄土高原地区当前生态环境恶劣。为有效地在这一地区开展生态环境保护与治理工作 ,有必要对其演化历程与特点进行深入的研究。对此 ,本文强调要加强人类历史时期生态环境变化历程与规律的研究 ,而且要紧密结合人为活动之影响开展综合性研究 ;同时概述了这一地区人类历史时期生态环境变迁历程 ,揭示了演化特点 ,并据之提出了具体的推进这一地区可持续发展的对策     

The relevance of vein texture in understanding the past hydraulic behaviour of a crystalline rock mass: reconstruction of the palaeohydrology of the Mecsekalja Zone,south Hungary

This study reconstructs the palaeohydrogeologic evolution of the shallow‐to‐moderate Mesozoic subsidence history for the Mecsekalja Zone (MZ), a narrow metamorphic belt in the eastern Mecsek Mountains, Hungary. Brittle deformation of the MZ produced a vein system with a cement history consisting of five sequential carbonate generations and one quartz phase. Vein textures suggest different fluid‐flow mechanisms for the parent fluids of subsequent cement generations. Combined microthermometric and stable‐isotope measurements permit reconstruction of the character of subsequent fluid generations with different flow types, as defined by vein textures, yielding new information regarding the hydraulic behaviour of a metamorphic crystalline complex. Textural observations and geochemical data suggest that fracture‐controlled flow pathways and externally derived fluids were typical of some flow events, while percolation through the rock matrix and the relationship to the Cretaceous volcanism and dyke emplacement were typical of others. The difference in the mode of calcite deposition from pervasive fluids (i.e. pervasive carbonatisation along grain boundaries versus deposition in antitaxial veins) between two calcite generations related to the volcanism inspired a stress‐dependent model of antitaxial vein growth. Textural and isotope variations in a vein generation produced by the same parent fluid indicate rock‐dependent hydraulic behaviour for different rock types, distinct action of the contemporaneous fracture systems and different extents of fluid–rock interaction. Cathodoluminescence microscopy and fluid‐inclusion microthermometry shed light on the possible role of hydraulic fracturing in the formation of massive calcite. The time of formation was estimated from the isotope composition of the oldest calcite generation and its presumptive relationship with the sedimentary sequences to the north, whereas microthermometry permitted conciliation of the reconstructed flow sequence with the Mesozoic subsidence history of the Mórágy Block (including the MZ).     

The reconstruction of past environments through small mammals: from the Mousterian to the Bronze Age in El Mirón Cave (Cantabria,Spain)

El Mirón is a large cave in the Cantabrian Cordillera of northern Spain that presents a long archaeostratigraphic sequence radiocarbon-dated by over 60 assays to between 41,000 and 2000 BP. The sediments, collected from four areas within the cave and sieved-washed with fine wire meshes, contain microvertebrate remains of fish, frogs, lizards, birds and mammals, of which the latter are most abundant. Preliminary taphonomic analysis suggests that the microvertebrates were naturally collected by owls and (less) small carnivores. Small mammal assemblages are useful for palaeoenvironmental reconstruction because they are linked to particular habitats and are sensitive to environmental changes. The small mammals from El Mirón are ideal for this because sample sizes are large, bone preservation is good, and the stratigraphic sequence is long. In this paper we reconstruct the late Quaternary environments in the Cantabrian region of Spain using small-mammal assemblages from El Mirón Cave. On the basis of the ecologic adaptations of this suite of fauna, the majority still extant, we have identified seven habitat types, which are plotted through time. The evolution of the small mammal assemblages at El Mirón reveals seven major climatic shifts that correspond closely to the climatic changes recognized in the Iberian Peninsula during the last 41 kyr.     

清前中期黄土高原地区沿边军事城镇及其功能的变迁

清代黄土高原地区沿“边”军事城镇多承袭明制 ,并在一个相当长的时期仍然发挥着军事功能 ;与以前不同的是 ,本域军事城镇在新形势下呈现出总体的衰落、数量减少和功能转化。具体表现在军事城镇行政化、城镇自然消亡及由兵员锐减而导致的军事功能减弱等 ;沿“边”地区增置的军事防卫城堡也不少 ,但其地理分布具有明显的地域特征