首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Site investigations that aim to sufficiently characterize a soil profile for foundation design, typically consist of a combination of in situ and laboratory tests. The number of tests and/or soil samples is generally determined by the budget and time considerations placed upon the investigation. Therefore, it is necessary to plan the locations of such tests to provide the most suitable information for use in design. This is considered the sampling strategy. However, the spatial variability of soil properties increases the complexity of this exercise. Results presented in this paper identify the errors associated with using soil properties from a single sample location on a pad foundation designed for settlement. Sample locations are distributed around the site to identify the most appropriate sample location and the relative benefits of taking soil samples closer to the center of the proposed footing. The variability of the underlying soil profile is also shown to a have a significant effect on the errors due to sampling location. Such effects have been shown in terms of the statistical properties of the soil profile. The performance of several common settlement relationships to design a foundation based on the results of a single sample location have also been examined.  相似文献   

2.
Multi‐element archives housed within archaeological soils and sediments are useful for identifying ancient human activities invisible to routine methodologies. These records, however, are rarely studied in the Canadian Arctic. Contributing to this area of research, we address the fundamental issue of isolating natural and anthropogenic multi‐element signatures in archaeological soils from the region. We specifically investigated the element record in the soil system at the Ikirahak site, a Taltheilei hunter‐gatherer camp in southern Nunavut that was established roughly 2000 years ago. Ikirahak soils displayed high potential for the preservation of anthropogenic element additions. This owes to the fine textures, high cation adsorbance capacities and acidic pH levels of the local soils, as well as the absence of processes such as brunification and solifluction. Multi‐element characterization was accomplished using x‐ray fluorescence and inductively coupled plasma ‐ mass spectroscopy. Several locations with anomalous concentrations were pinpointed using enrichment factors. Natural and anthropogenic signals were untangled using categorical principal components analysis of a mixed quantitative/qualitative data set comprised of the element concentrations and contextual information such as the presence of specific archaeological materials, organic matter content, and vegetation communities. Results indicated that enrichments in CaO, P2O5, Ba, Fe2O3, MnO, Cu and Sc across the site relate to the disposal of burned refuse that was produced in pit‐house hearths. Concentrations of Li, Na, K, Rb and Cs (alkali metals), Mg and Sr (alkaline earths), Ti, V, Cr, Ni, Zn, Y, Zr, Nb, Mo and Hf (transition metals), Al, Ga and Pb (post‐transition metals), and La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu (rare earths) were linked to esker and lacustrine parent sediments.  相似文献   

3.
The last hominin occupations of Gran Dolina cave at Atapuerca are represented by layer TD10‐1. This layer has yielded high densities of anthropogenic bone and lithic remains that suggest the existence of a referential hominin campsite. Micromorphological analysis was carried out in order to reconstruct site formation processes and to find traces of hominin activity in the sediments. Results show that TD10‐1 is an autochthonous deposit whose components are derived from a local, degraded cave entrance environment. The base of TD10‐1 represents a moist, semi‐sheltered environment associated with anthropogenic input and low sedimentary rates, while the rest of the deposit represents a non‐anthropogenic, more open environment with higher rates of sedimentation. The TD10‐1 archaeological assemblages have not undergone long transport or strong postdepositional disturbance. Further interdisciplinary analyses are needed to characterize the types and intensity of the hominin activities recorded in TD10‐1. © 2008 Wiley Periodicals, Inc.  相似文献   

4.
Prehistoric stone alignments and their associated terraces are common in upland ecozones of the American Southwest. These features are generally considered the archaeological consequences of “runoff agriculture” dedicated to domesticated‐plant production. Furthermore, researchers have theorized that such production decreased soil fertility and ultimately promoted abandonment of the alignments, terraces, and surrounding landscapes. Recent investigations show that cultivated Mollisols indeed have less organic matter and less available P, and elevated pH, as well as several textural changes. In contrast, cultivated Aridisols have elevated CaCO3, available Ca, and cation‐exchange capacity, as well as no textural changes. The developing picture, however, is that small‐scale runoff agriculture has had largely benign effects on soil fertility and that anthropogenic terraces likely were abandoned for reasons unrelated to their productivity. © 2000 John Wiley & Sons, Inc.  相似文献   

5.
A computer simulation model has been developed to investigate the postdepositional changes on archaeological sites due to soil erosion in a semiarid (Mediterranean) environment. Both soil matrix and archaeological artifact movement are accounted for by the model. The model is applied to a series of hypothetical site configurations on hillslopes, using archaeological structures, to observe the morphological changes due to slope form. The results show considerable variation in site preservation potential, relating to different initial spatial patterning of the site and initial slope form. The model predicts thresholds for the start of movement by artifacts, and suggests a correlation between the location of deposition and the potential for disturbance of the artifact record. Implications are drawn from the results of the simulations, both in terms of archaeological theory and practice, and in terms of site conservation and management. The simulation method is recognized as a useful tool for the investigation of natural site formation processes. © 1994 John Wiley & Sons, Inc.  相似文献   

6.
江苏省土壤重金属分布特征与污染源初步研究   总被引:2,自引:2,他引:2  
以24 186个表层土壤(0~20 cm)和6 127个深层土壤(150~200 cm)样品之Cd、Hg、Pb、As等含量数据为基础,研究了江苏全省土壤环境的重金属分布与主要污染特征.结果表明.全省自然土壤环境与人为活动土壤环境的重金属元素分布都不均匀,但人为活动土壤环境中的不均衡程度远高于自然土壤环境:全省农田中有1.02%的土壤受到Cd、Hg、Pb等8种重金属的严重污染,苏州市、无锡市土壤环境被重金属污染的程度相对严重;工业化、城市化进程中的人为活动及自然地质作用都是引起江苏局部土壤重金属污染的重要原因,自然成因的重金属污染土壤多呈面状、多元素、低强度、双层污染等特点,从而与人为成因的重金属污染土壤有所区别.  相似文献   

7.
This paper focuses on the late Holocene occupation of hunter‐gatherers at the Marazzi 2 site located on the northwestern steppe of Tierra del Fuego, Chile. Our aim is to understand stratigraphy, formation processes, and pedogenesis with respect to human occupation over the last 3000 years. Based on archaeological excavations on a fluvial terrace of the Torcido River, we integrate soil micromorphology, mineralogy, geochemistry, magnetic susceptibility, and geomorphology, as well as the micro‐ and macrofrequency distributions of archaeological material. A micro‐taphonomical perspective is also applied to anthropogenic components recorded in sedimentary thin sections. We discuss various events in the interplay between soil development and human occupation through time. Marazzi 2 was witness to aggradation and pedogenesis with an episode of surface stability coincident with a phase of more intense human occupation at about 860 BC. Taphonomic analysis suggests that there are multiple occupation events mixed together, probably by biomechanical processes, resulting in a palimpsest with poor temporal resolution.  相似文献   

8.
Palynological investigation is one of the most important tools for reconstructing past vegetation. Some plants have proved to be relatively sensitive indicators of human activity, but most of them are not specific. In this paper we propose a method which can be used for the verification of phases of anthropogenic impact on vegetation distinguished in pollen diagrams. In this work we adopted the existing molecular methods for tracking bacterial ancient DNA of Bifidobacterium and Bacteroides‐Prevotella (known as human‐ and cow‐specific genetic markers) in palynologically and archaeologically associated sediments. This method can be helpful in determining local human presence, especially in those time periods when pollen analysis has not always been very discriminating (Palaeolithic, Mesolithic) and at sites without archaeological evidence. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

9.
Ancient human activities have resulted in important elemental enrichments in soils at archaeological sites. Nevertheless, the spatial extent of such elemental enrichment signals is rarely studied. Our research addresses this theme by studying the characteristics and extent of the geochemical enrichment halo around the monumental Colonnaded Street of the Hellenistic to Byzantine city of Sagalassos in southwest Turkey. Given the complex geology of the area, a strategy applying multivariate statistical data analysis techniques is proposed to identify whether the enrichments have a geological or an anthropogenic source. In addition, we evaluate how a wide variety of natural and anthropogenic processes may influence the distribution of elements around the site. In this paper, it is shown that enrichments of P and Pb are present up to a distance of 450 m and 150 m away from the city, respectively. Hence, we conclude that the extent of chemical enrichment haloes around archaeological sites may be element specific.  相似文献   

10.
This study proposes the method of simulating spatial patterns and quantifying the uncertainty in multivariate distribution of heavy metals (Cr, Cu, Ni, and Zn) by sequential indicator simulation (SIS) combined with conditional Latin hypercube sampling (cLHS) in Changhua County, Taiwan. The cLHS is used for a sampling then for SIS mapping and assessing uncertainties of heavy metal concentrations. The indicator variogram results indicate that the 700 cLHS samples replicate statistical multivariate distribution and spatial structure of the 1,082 samples. Moreover, the SIS realizations based on 700 cLHS samples are more conservative and reliable than those based on 1,082 samples for delineating soil contamination by all heavy metals with the exception of Zn. Given adequate sampling, soil contamination simulation provides sufficient information for delineating contaminated areas and planning environmental management.  相似文献   

11.
Geophysical techniques have been widely employed for the noninvasive location of burial sites in archaeological and forensic investigations. This approach has met with varying degrees of success, depending on factors such as equipment choice, survey methodology, burial type, and geological setting. This paper reports the results of a multitechnique geophysical survey carried out immediately prior to the salvage excavation of two Indigenous burials from an eolian dune in coastal South Australia. Ground‐penetrating radar was not successful in defining the location of the burials owing to the disturbed nature of the local stratigraphy. Magnetic field intensity and apparent magnetic susceptibility surveys identified discrete anomalies that coincided with the location of skeletal material revealed during excavation, which we hypothesize to be due to burning or ochre use during funerary practices. Despite the spatial association of these features, subsequent laboratory analyses of the mineralogy and magnetic properties of sediments collected from the site failed to find a definite cause of the anomalies. Nevertheless, the association between them and the primary interment locations has implications for archaeological surveys carried out in the Australian coastal zone, as it highlights the potential of magnetic field intensity and apparent magnetic susceptibility geophysical techniques undertaken with a more refined survey methodology to afford a noninvasive, culturally appropriate means through which to detect Indigenous burials. This approach may prove particularly useful in areas with disturbed stratigraphy where ground‐penetrating radar is less effective. © 2010 Wiley Periodicals, Inc.  相似文献   

12.
Geophysical techniques have been widely employed for the noninvasive location of burial sites in archaeological and forensic investigations. This approach has met with varying degrees of success, depending on factors such as equipment choice, survey methodology, burial type, and geological setting. This paper reports the results of a multitechnique geophysical survey carried out immediately prior to the salvage excavation of two Indigenous burials from an eolian dune in coastal South Australia. Ground‐penetrating radar was not successful in defining the location of the burials owing to the disturbed nature of the local stratigraphy. Magnetic field intensity and apparent magnetic susceptibility surveys identified discrete anomalies that coincided with the location of skeletal material revealed during excavation, which we hypothesize to be due to burning or ochre use during funerary practices. Despite the spatial association of these features, subsequent laboratory analyses of the mineralogy and magnetic properties of sediments collected from the site failed to find a definite cause of the anomalies. Nevertheless, the association between them and the primary interment locations has implications for archaeological surveys carried out in the Australian coastal zone, as it highlights the potential of magnetic field intensity and apparent magnetic susceptibility geophysical techniques undertaken with a more refined survey methodology to afford a noninvasive, culturally appropriate means through which to detect Indigenous burials. This approach may prove particularly useful in areas with disturbed stratigraphy where ground‐penetrating radar is less effective. © 2010 Wiley Periodicals, Inc.  相似文献   

13.
对于人为因素或自然因素造成的农田土壤重金属元素污染,需要进行大面积的土壤环境质量调查和分类管控,然而传统的采样测试方法存在工作量大、代价高等问题。可见—近红外(Vis-NIR)反射光谱是一种快速低成本获取土壤理化信息的手段。为研究Vis-NIR反射光谱预测模型划分土壤重金属污染风险类别的能力,文章以典型人为污染地区(浙江温岭)和典型地质高背景地区(广西横县)的390份农田土壤为样本,测定8种重金属元素(As、Cd、Cr、Cu、Hg、Ni、Pb和Zn)的含量和pH值,并测定土壤Vis-NIR光谱。使用偏最小二乘(PLS)和支持向量机(SVM)算法建立回归模型,对土壤重金属含量和pH值进行预测,并基于预测值进行土壤重金属污染风险分类。结果显示,温岭土壤主要污染元素Cd和Cu的光谱模型回归预测偏差(RPD)分别为1.23和1.19,预测机制与有机质有关。横县土壤主要污染元素As和Cd的RPD分别为1.98和1.93,预测机制与铁氧化物和粘土矿物有关。地质高背景土壤重金属与铁氧化物的正相关性普遍较强,使得光谱模型对重金属含量预测准确度较高。温岭和横县土壤pH值的光谱模型RPD分别为1.76和1.68。土壤重金属污染风险光谱分类的总体 准确度分别为75.0%~100%(温岭)和80.0%~100%(横县)。将Vis-NIR光谱与遥感技术相结合,对农田土壤重金属污染风险进行快速分类总体是可行的。  相似文献   

14.
15.
Primary sand and gravel deposits in Britain play an important role in preserving our cultural heritage and are also a valuable aggregate resource. While an understanding of the extrinsic properties of the soil archive (such as pH, redox, groundwater) can provide a firstorder assessment of the potential risk to any archaeologically sensitive deposits, we have very poor definition of spatial variations in the extrinsic properties of soil that influence archaeological preservation at a regional and national scale. Developments in digital geological mapping, remote sensing, and geochemical survey data undertaken by the British Geological Survey (BGS) have, however, significantly extended capabilities in this respect and can potentially be used to provide a primary assessment of the sensitivity of the present soil archive and the potential risk from changes to the soil process on cultural material in areas earmarked for aggregate extraction. Two of the major factors affecting archaeological preservation—soil acidification and groundwater—can be mapped or predicted at scales of better than 1:50,000 across increasingly large parts of the country using a combination of regional hydrogeological, geophysical, and geochemical data. Additional data from site investigations may further refine preservation potential as a function of changes in redox potential and acidity. These data, maps and models can be used to (1) better establish a baseline for archaeological preservation at a regional and national scale and (2) improve our understanding of how the physical and chemical properties of the near surface environment can be managed to sustainably preserve archaeological materials in areas impacted by sand and gravel extraction. © 2009 Wiley Periodicals, Inc.  相似文献   

16.
Benson  R. C.  Yuhr  L. 《Environmental Geology》1993,22(4):296-307
Assessing the existence, location, and mapping of geologic anomalies, such as fractures and cavities within soil and rock, are common to both engineering and hydrologic project needs. There are numerous measurement techniques available to detect, map, and characterize fractures and cavities. A summary of the common methods available for fracture and cavity detection and mapping are presented along with their spatial sampling capabilities. The remote sensing and geophysical methods are but a small part of this list but provide a wide range of tools to attack the problem. They include some of the most effective methods for locating and mapping fractures and cavities and cover the complete range of spatial sampling, from regional to no more than the surface of a borehole wall. An understanding of all of the tools available and their spatial sampling limitations is a necessary part of planning and carrying out an effective fracture/cavity investigation.  相似文献   

17.
The conventional approach to assessing the archaeological record in most parts of the world involves a combination of excavation of stratified deposits and extensive survey of surface deposits. Although widely applied in Australia, in both research‐based and management archaeology, the method does not conform well to the nature of the surface archaeological record here. Over much of semi‐arid and arid Australia, archaeological “sites” are, in fact, accretion phenomena that are not easily interpreted as the outcome of short‐term behavioral events. Using results from twelve years of geoarchaeological research in western New South Wales, we demonstrate that there is considerable variability in landsurface age, and hence the “availability” of archaeological surfaces, over relatively short distances. Therefore, it cannot be assumed that stone artifact deposits, for example, that appear to be similar in character are of similar age. Data are also presented that demonstrate that the presence of artifacts on the surface, their apparent absence in sediments buried beneath the surface, and the apparent recent ubiquity of the archaeological record are all a function of geomorphic processes that, at the same time, expose some artifact deposits at the surface and erode and bury others amid large volumes of sediment. Interpreting the surface artifact record within a spatial and temporal geomorphic framework is crucial to understanding the past human behavior that the artifact deposits represent. © 2009 Wiley Periodicals, Inc.  相似文献   

18.
Digital evalutation of a series of correlative geo-specific maps in different scales and subsequent multivariate data processing in the form of entropy and neighbourhood analyses are the basis of a comparative selection of soil samples for the environmental specimen bank of the Federal Republic of Germany. By means of regionalisation algorithms, partly developed for, or specifically adapted to the present purpose, the optimum location of sampling points was determined and the result corroborated on large-scale maps or by visual inspection, respectively. In addition an index of representativity was defined, grouping soil taxa in terms of acreage and spatial autocorrelation.Once the spatial structure of the soil associations in an area to be sampled is thus determined variogram analysis, in the second step, contributes to definitely select the most appropriate specimens on the basis of a representative sampling grid and with respect to relevant properties, for instance cation or anion exchange capacities and biodegradability potential.  相似文献   

19.
Site formation processes at the Late Pleistocene rockshelter deposit of Obi‐Rakhmat were reconstructed through soil micromorphology and Fourier transform infrared spectroscopy (FTIR). The entire sequence has undergone limited diagenesis and is well preserved. The base of the stratified sequence represents a karstic setting with intermittent, low‐energy deposition of autochthonous gravitational debris and anthropogenic material in a wet, muddy environment. These sediments were post‐depositionally affected by episodic waterlogging. The bulk of the sequence overlying the karstic layers comprises a continuous series of primary freshwater spring deposits containing reworked anthropogenic material that was buried penecontemporaneously with calcium carbonate deposition. The top of the sequence is weakly cryoturbated, indicating a periodically cold, wet environment. No alluvial elements that could suggest sediment inputs from the nearby river terraces were documented. A single exogenous layer was identified, representing an episode of colluviation from directly above the rockshelter preceding a major roofspall event. The basal part of the sequence contains slightly reworked anthropogenic remnants of intense activities, including combustion. The anthropogenic elements present in the spring deposits show higher degrees of reworking, suggesting within‐layer translocation. The development of spring activity at the site did not cause humans to abandon the rockshelter; they continued to carry out their activities throughout a changing local environment. © 2009 Wiley Periodicals, Inc.  相似文献   

20.
The site at Hofstaðir in northeast Iceland has been central to the debate on pre-Christian Norse temples and temple-farm complexes throughout the Scandinavian world. Critical to an understanding of the site have been the various and conflicting interpretations of the great pit feature, which have included the hypotheses that it was intentionally made for the disposal of rubbish after temple feasts, that it was a cooking pit for large-scale food preparation within a temple–farm complex, and that it was the location of a rubbish tip for ordinary farmstead waste materials. In this article we test these competing hypotheses using the technique of thin section micromorphology. These analyses represent the first application of micromorphology to questions of archaeological site formation processes in Iceland, a volcanic island with commonly occurring Andisols. Although this soil type poses new challenges to archaeological soil micromorphology, it was found that pedofeatures, microstructures, and anthropogenic inclusions provide a basis for interpreting site formation processes on Andisols as on other soil types. We conclude that the pit feature had its origins as a sunken-featured building and that the hollow created by the building's abandonment and collapse was later filled with domestic farmstead waste. © 1999 John Wiley & Sons, Inc.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号