河南省新石器至夏商时期城邑与一般聚落空间关系研究     

闫丽洁  鲁鹏  陈盼盼  张莉  王霞 《第四纪研究》2020,(2):568-578

以河南省新石器至夏商时期65座城邑与4095座一般聚落为研究对象,采用核密度分析法、最近邻指数法、重心分析等GIS空间分析方法,按照裴李岗、仰韶、龙山、夏商这4个时期对城邑与聚落的密度、空间分布集聚程度以及重心位移演变关系进行了研究.分析表明:1)河南省新石器至夏商时期城邑的分布与聚落的密度关系密切,有83.08%的城邑位于聚落密度较大的地区,尤其是规模比较大的城邑几乎都分布在聚落密度较高的地方,只有少数城邑分布在聚落密度较小的地区;2)河南省仰韶时期至夏商时期城邑与聚落的集聚程度变化规律是一致的.集聚程度由高到低均为仰韶时期-夏商时期-龙山时期;3)河南省新石器至夏商时期聚落重心相对城邑重心分布在南面,聚落和城邑的重心均是在嵩山及其周边地区按逆时针方向移动,说明了河南省的文化核心区就在环嵩山地区,该地区在新石器至夏商时期文化发展中居于核心地位.河南省新石器至夏商时期城邑与一般聚落空间关系研究表明,城邑与一般聚落之间有着紧密的联系,两者空间分布格局的变化是气候及生产力发展水平双重影响下的结果.  相似文献   

古环境DNA与环境考古     

顾政权  王昱程  刘勇勤  杨晓燕  陈发虎 《第四纪研究》2020,(2):295-306

古环境DNA(ancient environmental DNA,简称ancient eDNA)指保存于古环境样品中的生物古DNA(ancient DNA,简称aDNA).与直接从古代生物遗存内获取的单一物种古DNA不同,古环境DNA为多种生物的混合DNA,常常以小片段DNA分子形式吸附在腐殖质和矿物颗粒上,主要从粪化石、牙结石、肠道残留物、冰川、冻土、泥炭、湖泊、海洋、洞穴和遗址沉积物等环境样品中获得.古环境DNA研究自1998年开始兴起,经历了早期的DNA条形码(DNA barcoding)古代物种鉴定,到DNA宏条形码(DNA metabarcoding)古代生物类群恢复,再到近期的鸟枪法宏基因组(shotgun metagenomic)古生态系统重建等发展历程,目前已形成了完善的研究体系,可以完成对古环境样品中大部分动物、植物和微生物物种的检测.相比于传统的动植物化石形态鉴定手段,古环境DNA研究具有样品用量少、方法简单快捷、不依赖于化石、一次实验可以确定大量物种信息等优势.目前,国际上的古环境DNA研究在古生态环境重建、古代农业发展、古代人类食性、人类扩散历史和人类活动对环境影响等环境考古领域的应用都取得了良好的进展并发表了大量成果,但国内相关研究还少有报道.本文综述了古环境DNA技术的发展、研究方法、应用方向及存在的问题等内容,认为随着古环境DNA研究技术的日趋完善,其在环境考古学中的应用前景也将更加广阔.  相似文献   

Development of Iron Speciation Reference Materials for Palaeoredox Analysis     

Lewis J. Alcott  Alexander J. Krause  Emma U. Hammarlund  Christian J. Bjerrum  Florian Scholz  Yijun Xiong  Andrew J. Hobson  Lesley Neve  Benjamin J. W. Mills  Christian Mrz  Bernhard Schnetger  Andrey Bekker  Simon W. Poulton 《Geostandards and Geoanalytical Research》2020,44(3):581-591

The development and application of geochemical techniques to identify redox conditions in modern and ancient aquatic environments has intensified over recent years. Iron (Fe) speciation has emerged as one of the most widely used procedures to distinguish different redox regimes in both the water column and sediments, and is the main technique used to identify oxic, ferruginous (anoxic, Fe(II) containing) and euxinic (anoxic, sulfidic) water column conditions. However, an international sediment reference material has never been developed. This has led to concern over the consistency of results published by the many laboratories that now utilise the technique. Here, we report an interlaboratory comparison of four Fe speciation reference materials for palaeoredox analysis, which span a range of compositions and reflect deposition under different redox conditions. We provide an update of extraction techniques used in Fe speciation and assess the effects of both test portion mass, and the use of different analytical procedures, on the quantification of different Fe fractions in sedimentary rocks. While atomic absorption spectroscopy and inductively coupled plasma‐optical emission spectrometry produced comparable Fe measurements for all extraction stages, the use of ferrozine consistently underestimated Fe in the extraction step targeting mixed ferrous–ferric minerals such as magnetite. We therefore suggest that the use of ferrozine is discontinued for this Fe pool. Finally, we report the combined data of four independent Fe speciation laboratories to characterise the Fe speciation composition of the reference materials. These reference materials are available to the community to provide an essential validation of in‐house Fe speciation measurements.  相似文献   

基于数字化技术的古建筑保护研究   总被引：2，自引：0，他引：2  

范张伟  邢昱 《北京测绘》2010,(3):18-21,35

介绍了地面三维激光扫描和GIS等新技术手段的优势和特点,探讨其在古建筑保护中的应用,并以河南开封的国家级重点保护文物"开封铁塔"为研究对象,以三维激光扫描点云为基础数据,结合地理数据库和三维建模技术,建立了古建筑数据库。利用ArcGIS Engine二次开发平台,设计了具有多维展示、数据库管理、监测分析和决策支持等功能的古建筑数字化保护系统,从技术层面上加强了对古建筑保护的力度。  相似文献   

从《大统通占》星表重新考察明初的恒星观测---兼论传统星官的变化          下载免费PDF全文

褚龙飞  杨伯顺 《天文学报》2022,63(2):15-35

《大统通占》是明初钦天监编纂的占书,其中保存了一些明初恒星观测数据.试图以此重新考察明初的恒星观测情况.首先,分析了该书的成书年代,指出其应完成于永乐四年至二十三年之间.然后,以依巴谷星表(2007)为标准,对该书记载恒星数据的赤纬误差进行傅里叶分析,发现这些数据应观测于洪武年间,且其精度达到明末以前星表的最高水平.另外,梳理了明初钦天监观测恒星的条件,认为其观测水平的提高与郭守敬对仪器的改进措施密切相关.最后,对这份精密星表的研究也进一步揭示了古代星官发生的历史变化.  相似文献   

Aeolian dynamics of transgressive dunefields on the southern Mozambique coast,Africa          下载免费PDF全文

Lucas Lavo António Jimo Miguel  João Wagner Alencar Castro 《地球表面变化过程与地形》2018,43(12):2533-2546

A relatively unknown coastal zone of southern Mozambique in Africa is covered by vast mobile and stabilized dunefields. The aeolian dynamics of these transgressive dunefields are studied based on mobility and stability models, statistical analysis of climate data and topographic profiles. Detailed analyses of regional winds, rainfall records, atmospheric temperature records and annual monitoring of dune migration rates helped to find reliable data about instantaneous aeolian sand transport rates, wind drift potential, dune mobility and dune migration rates. The data obtained suggest that the coastal transgressive dunefields are controlled by the southeast winds, availability of loose sediments on the beach, the presence of headland boundary between Maputo and Gaza provinces and the appropriate deposition spaces between the coastline and lacustrine‐lagoon systems. Two distinctive segments of transgressive dunefields were identified in the region studied, including the northern segment of Maputo province with active (mobile) and semi‐vegetated dunes that migrate 23 m/yr landward, and Gaza province dunefields with stabilized (vegetated) and semi‐vegetated dunes. The data obtained in this research have considerable potential to make a valuable contribution to the study of coastal dunefields. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Barrier response to sea level rise and storms          下载免费PDF全文

Chris Houser 《地球表面变化过程与地形》2018,43(11):2481-2483

This commentary brings together, as a Virtual Special Issue, several recent papers in Earth Surface Processes and Landforms that improve our understanding of coastal barrier response to relative sea level rise and a change in the frequency and/or magnitude of storm events. The ability to predict barrier response depends on the ability to quantify the spatial and temporal scales of sediment exchange amongst the nearshore, beach and dune. This exchange controls the height of the dune, which in turn determines the transfer of sediment to the backbarrier through washover and/or blowouts. The papers in this issue provide new insight on beach–dune interaction and the importance of this interaction to long‐term barrier evolution across a range of sites and scales, and how active management can influence this interaction and alter barrier response. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Impacts of artificially planted vegetation on the ecological restoration of movable sand dunes in the Mugetan Desert,northeastern Qinghai-Tibet Plateau     

Yanfu Li  Zhiwei Li  Zhaoyin Wang  Wenlong Wang  Yanhong Jia  Shimin Tian 《国际泥沙研究》2017,32(2)

Controlling desertification is an important ecological target for the Qinghai-Tibet Plateau of China, where studies on impacts of vegetation restoration measures on sandy soil improvement are still lacking. The Mugetan Desert in Guinan County, Qinghai Province, northeastern Qinghai-Tibet Plateau is a repre-sentative ecological restoration area. The impacts of artificial vegetation on the ecological restoration and its properties are studied by using field investigation and sample testing including contents of the surface layer and the vegetation composition of movable, semi-fixed, and fixed sand dunes. Results demonstrate that the moss crust has formed on the surface of a sand dune which has become fixed after 30 years under the impact of artificial vegetation (i.e. Cathay poplar). Meanwhile, the clay minerals, organic matter, and other soil available nutrients have markedly increased. A correlation has been found between these materials, i.e., clay minerals and organic matter content increasing with silt and clay increases with reduction in sand content. In addition, soil nutrient were positively correlated with the increase of plant diversity.Under the current meteorological conditions, the artificial vegetation is helpful for the stabili-zation of sand dune and the ecological restoration in the Mugetan Desert.  相似文献   

Morphological evolution of a barchan dune migrating past an offshore wind farm foundation     

Amelia J. Couldrey  Thomas Benson  Michiel A.F. Knaapen  Kerry V. Marten  Richard J.S. Whitehouse 《地球表面变化过程与地形》2020,45(12):2884-2896

As the number of manmade structures installed on the seafloor is increasing rapidly, we seek to understand the impact of these immobile obstacles on marine geomorphological processes, such as the evolution of bedforms. A 5.8 m diameter monopile foundation was installed at the case study offshore windfarm approximately 30 m ahead of an approaching barchan (crescent-shaped) dune. The impact of the monopile on the dune's evolution was analysed using six multibeam bathymetry surveys spanning 20 years. To substantiate this analysis, coupled three-dimensional numerical modelling of flows and sediment was conducted in which the scour inducing bed shear stresses were calculated from the modelled turbulent kinetic energy. Following the installation of the monopile, the mid-section of the dune accelerated and stretched in the direction of the wake of the monopile. Four years after the monopile's installation the rest of the dune had caught up, flattening out the slip face within half the dune's length downstream of the monopile. Due to the modified flow field, the dune was scoured deeply at the base of the monopile to a depth of 6.8 m (supported by the model results that predicted a scour depth exceeding 2 m over a period of just a few days). The surveyed volume of material scoured amounted to 8% of the total dune volume. Whilst the process of scouring occurs at a timescale of days to weeks, the dune migrated on average by 25 m/yr. The difference in the timescale of the two processes allowed the scouring to occur through the full thickness of the dune. The scoured dune profile recovered rapidly once the dune migrated downstream of the monopile. This article demonstrates how large geomorphological features can intercept and migrate past a monopile foundation without long-lasting impacts on the integrity of the feature or the foundation. © 2020 John Wiley & Sons, Ltd.  相似文献   

多源数据古塔变形监测研究     

王国利  吴桂凯  王晏民  郭明  赵江洪  高超 《地球信息科学学报》2018,20(4):496-504

建筑遗产的变形监测是遗产可持续保护的重要保障,塔类古建筑是古建筑中的典型,造型突兀高耸,变形包含沉降、倾斜、弯曲及扭转等多种状态,传统监测手段难以满足其监测需求。本文针对某古塔的变形问题,以传统测量方法为参照,采用地面激光雷达和无人机近景摄影测量技术获取古塔三维数据,结合古塔监测指标对3种方法流程、特点、数据及结果精度进行对比,通过融合三维模型对古塔病害分析,从不同的角度反映出古塔的变形状况。通过对比可知：常规测量方法进行古塔变形监测,具有精度高,应用灵活特点,适用于古建筑整体姿态或者典型特征监测;地面激光雷达技术精度高、设站灵活,能够精确分析古塔整体及部分局部的形变,但易受扫描视角的影响;无人机近景摄影测量技术建立的古塔三维模型具有高精度及真实的色彩,对整体及细节纹理表现好,但是无法获取塔内部狭窄空间的三维数据;融合数据能有效弥补单一数据源的缺陷,实现古塔全面病害分析。数据精度方面,地面激光扫描及近景摄影测量技术均可达到毫米级精度,传统监测方法在沉降与倾斜监测方面优于前2种方法,在监测全面性方面则前2种方法更具优势。  相似文献