INVESTIGATING SEASONALITY AND SEASON OF BIRTH IN PAST HERDS: A REFERENCE SET OF SHEEP ENAMEL STABLE OXYGEN ISOTOPE RATIOS

Intra‐tooth sequential analysis of enamel δ¹⁸O is currently used to investigate birth seasonality in past animal populations, offering new insights into seasonal availability of animal resources, herd management and seasonality of site occupation. Reference data sets are still required to address two major difficulties: (1) that inter‐individual variability in the record of the seasonal cycle is affected by tooth size; and (2) that the season of birth cannot be directly estimated from the timing of tooth growth, because of a delay in enamel mineralization. We present a data set acquired on the lower second molar of 10 modern sheep from Rousay (Orkney) born within a few weeks of each other in April/May and submitted to the same environmental conditions until death. All sheep have recorded a sinusoidal pattern of δ¹⁸O variation spanning approximately a year. From the difference between the expected and the measured time sequence, the delay of enamel mineralization is estimated to be 5–6 months. The data set is then described using a model mainly based on a cosine function. The period, corresponding to the length of the M2 crown formed over a year, averaged 35.8 mm. A very slight variation of tooth growth rate with time and no attenuation of the isotopic signal towards the cervical margin of the crown could be detected in this data set. The lowest δ¹⁸O values, corresponding to the sheep's first winter, were tracked at a distance from the enamel/root junction that varied between 23.0 and 30.3 mm (x_min mean = 27.6 mm); the highest δ¹⁸O values, corresponding to the sheep's second summer, were between 6.3 and 11.6 mm (x_max mean = 9.9 mm). Most of the variability can be attributed to tooth size. When normalized on the period, x_min and x_max are 0.28 (± 0.05) and 0.78 (± 0.05) on average, meaning that the Rousay sheep have recorded the minimum and maximum δ¹⁸O values on average at 78% and 28%, respectively, of the end of the periodic cycle recorded in the second molar.     

SELECTION AND HEATING OF COLOURING MATERIALS IN THE MOUSTERIAN LEVEL OF ES‐SKHUL (c. 100 000 YEARS BP,MOUNT CARMEL,ISRAEL)

The transformation of yellow goethite into red hematite by heating has long been assumed for Palaeolithic red artefacts excavated close to fireplaces. However, this transformation is extremely rare. Using SEM–FEG–EDX, PIXE–PIGE, TEM and μXRD, we characterized the mineralogical and chemical compositions of four microsamples of colouring materials from the Mousterian layer B in the es‐Skhul rock‐shelter, from about 100 kya ago. For some colouring materials, the Mousterian people of es‐Skhul chose to gather remote yellow lumps for heating. Their significant transport distance provides evidence of the possible high cultural value of these colouring materials for transformation into red pigments.     

现代测绘技术在古建烫样数字化项目中的应用

烫样是研究清代皇家建筑的珍贵文物,为配合文物信息数字化工作的开展,针对烫样数据的采集和处理方法进行了深入研究。在综合考虑多种数据采集方法的特点及烫样数字化记录的难点后,选择使用手持式三维扫描仪与多视角三维重建技术相结合的方式来进行烫样的基础数据采集,并通过实践总结出了一套完整的数据采集和处理工作流程。与此同时,针对成果可能的应用方式做了些许尝试,且为数据的后期维护与进一步利用拟定了数据管理系统的建设方案。     

3S技术在遗址探查中的应用

常规遗址探查方法,普查难度大,影像上不能直接识别小型遗址.为此,应用3S技术(遥感技术(RS)、全球定位系统(GPS)、地理信息系统(GIS))在遗址探查中的作用和优势,提出了基于地物空间关系知识、多源信息复合探查的思路.应用结果以巢湖柘皋区为例,将该区遥感图像中提取的古河道信息层和数字化后的地形图上标注为独立物(其中包括已知、疑似遗址点)层叠合,在地理信息系统中总结已知遗址点的分布规律,筛选出疑似遗址点,并将其GPS定位信息与近期巢湖文物管理部门野外实测记录对比,提取的疑似遗址点中包含了普查记录的遗址.3s技术的应用表明,该方法可为考古普查工作节省大量时间、人力和物力.     

基于海量点云数据的大雁塔三维重建

古建筑三维重建已成为历史遗迹保护与修复的重要内容。为了探讨三维激光扫描数据的获取流程、数据处理方法,以三维激光扫描获取的大雁塔海量点云数据为例,研究了古建筑三维重建中点云数据获取与处理的详细过程。联合Cyclone、AutoCAD和3D-Max软件的优点构建了大雁塔真实的横面、剖面、立面模型,其中重点研究了海量点云数据在Cyclone软件中分块建模的方法。结果表明:将拼接好的大雁塔海量点云数据分块建模,不仅加快了数据处理的速度,而且符合精度要求。在点云数据拼接时采用标靶拼接和同名点拼接相结合及测站间两两拼接之后再整体拟合平差的方法,减少了拼接中的误差,使每站拼接误差都不超过3cm。在建模过程中的墙体拟合是上万个点云经过平差计算得到,精度高达2mm。最后在3D-Max软件中组合、渲染和贴图,真实地构建了大雁塔三维立体模型。为古建筑数字化存档和后期的修缮工作提供了重要的依据。     

文物真三维数字建模技术在秦始皇兵马俑博物馆中的应用——以一号坑陶俑为例

随着高新技术的发展,文保应用研究中引入了三维扫描技术。通过对秦兵马俑一号坑陶俑的扫描实例,介绍了一套利用三维激光扫描技术建立文物真三维模型的基本流程及方法,并通过文物真三维数据管理系统对模型进行展示、分析与研究。文物真三维数据模型的建立,使全面观察研究、再现和重建遗迹及文物成为可能,为文物的数字化展示、数字博物馆的建立、文物鉴赏以及文化遗产的保存提供了新思路。     

考古地层的三维建模方法在秦始皇帝陵考古勘探中应用尝试

为了更清楚地展示秦始皇帝陵地区考古地层的三维空间关系,并为后期考古工作中空间数据挖掘做准备,借鉴三维地质建模技术,提出了考古地层三维建模方法。基于探孔数据构建了考古地层三维模型。该模型清楚地展示了秦始皇帝陵地区考古地层的三维空间关系,为田野考古数字化工作提供一种新思路、新方法。     

龙门石窟万佛洞观世音菩萨像虚拟修复研究和实践

龙门石窟万佛洞前室南壁唐代观世音菩萨像,因其精湛的雕刻技艺、典雅婀娜的造型,被誉为“龙门最美观世音”。受人为及自然双重因素的影响,造像面部残缺,彩绘消失殆尽。对其进行虚拟修复,重现其完整样貌,对考古科研和展示利用具有重要意义。以史料照片为依据,采用三维数字化与雕塑修补相结合的技术方法,实现残损造像形体和石质质感的虚拟修复,并通过高精度SLA 3D打印的方式输出虚拟修复的实体模型。利用XRF光谱分析、拉曼光谱分析技术,测定了该造像残存颜料的成分。在此基础上,依据残存颜料的分布情况和龙门同期造像的色彩风格,完成残损观世音菩萨像的色彩虚拟修复。此科研实践设计了对残损文物形体和色彩虚拟修复的完整技术路径,验证了所选技术路线的可行性,并实现了实体模型的妆銮赋色和在展览展示中的利用。     

基于三维扫描模型的兵马俑足踝有限元分析

利用三维扫描技术获取兵马俑残片的三维点云数据,结合Geomagic Studio和Hypermesh建立高精度的兵马俑足踝残片三维实体网格模型。通过基于ABAQUS的重力作用下的有限元分析,研究足踝部分的Von Mises应力和变形特征,以确定足踝处的受力薄弱部位。为进一步探究模型各残片的最佳点云简化比例,采用点云简化模型进行相同工况的有限元分析,以验证点云简化的可靠性。结果表明:结构在重力作用下可保持安全稳定的状态,相对薄弱部位位于左腿足踝处;对于大部分残片,其最佳简化比例在60%～70%,简化后可有效缩短模型实体化处理时间;采用简化模型得到的有限元结果,其最大Mises应力相比于原始模型的误差小于15%,且应力云图和变形图形状接近,模型简化具有可靠性。     

Chemical tracers of Lusitanian amphorae kilns from the Tagus estuary (Portugal)

In this paper, the characterization of Roman amphorae from the Porto dos Cacos (PC) and Quinta do Rouxinol (QR) workshops, in the Tagus estuary, dating to a period between the 1st and 5th century AD was carried out on the basis of instrumental neutron activation analysis data on 260 amphorae fragments, together with mineralogical compositional studies obtained by X-ray diffraction.