A reconstruction of the pre‐8th century B.C. palaeotopography of central Corinth,Greece

The pre‐8th century B.C. palaeotopography of the center of Corinth, southern Greece, was reconstructed using a combination of geological and geomorphological observation and archaeological evidence. Preserved areas of calcrete and overlying calcareous soil, which represent surviving remnants lying close to the pre‐8th century B.C. land surface, were mapped. The geology of the site was also mapped. The topography of Corinth in pre‐8th century B.C. times was radically different from that observed today. Most topographic modification occurred as a result of quarrying from a line of Pleistocene oolitic sand dunes for construction‐stone during antiquity. The reconstruction presented differs in key respects from previously published palaeotopographies, which did not include geological evidence. The results of the new reconstruction illustrate the importance of combining geological, geomorphological, and archaeological evidence and have implications for the urban development of Corinth in post‐8th century B.C. times. © 2004 Wiley Periodicals, Inc.     

Local‐scale adaptations: A modeled assessment of soil,landscape, microclimatic,and management factors in Norse home‐field productivities

Adaptation of farming practices to inherent site conditions was essential to the success of Norse colonization in pristine landscapes. A key factor in the initial success of colonization, or landnám, of Iceland was management of the area adjacent to the domestic dwelling, the home‐field, to provide fodder for over‐wintering livestock. In this paper we examine three settlement home‐fields in the Mývatn and Laxá valley area of northeast Iceland. Contemporary evidence reveals a distinct climatic toposequence together with differences in the nature of the inherent soils between sites. By considering the influence of these differences, microscale adaptations in early land management practices in the production of hay are sought within a tightly defined chronological context. Using an integrated agroecosystem modeling approach, the factors affecting long‐term sustainability of hay production in the Norse home‐field are examined. Results indicate that regional‐level climate differences will have an impact on production, especially pronounced cold periods. It is also clear that small‐scale climate factors, as well as inherent soil differences between sites influenced productivity for the Norse farmer. However, productivities overall are at subsistence level, emphasizing the need for optimized land management to sustain home‐field production. After examining different management scenarios, it is apparent that the effect of an increased rate of manuring will be most apparent during the first century of settlement; thereafter the effect is relatively diminished. © 2008 Wiley Periodicals, Inc.     

Rise and Fall of an Egyptian Oasis: Artesian Flow,Irrigation Soils,and Historical Agricultural Development in El‐Deir,Kharga Depression,Western Desert of Egypt

The present study examines the geoarchaeological history of an oasis in Kharga Depression in central Egypt. El‐Deir is renowned for its Ptolemaic temple and Roman fortress on the road from former Hibis (Kharga) to the Nile Valley. During the survey, spring mounds and irrigation soils belonging to an ancient agricultural zone were discovered, and further documented by ceramics found on the site. Our methodology combines the geomorphological interpretation of landforms (especially yardangs) with ceramics and ¹⁴C‐dated charcoal to distinguish and date former agricultural areas in El‐Deir. The results show that the oasis experienced several phases of soil accretion and destruction through time. Playa sediments were deposited in the humid early Holocene and severely eroded by deflation before the onset of irrigated agriculture between Pharaonic and Persian times. Very fast vertical soil accretion occurred in the Ptolemaic period, but irrigation soils were later destroyed during the Roman period by a combination of wind deflation and flash floods (second to fourth century A.D.), suggesting a period of climate instability. The case of El‐Deir invites reevaluation of constructive agencies for the development of irrigated land and destructive agencies as limiting factors for the sustainability of agricultural practices in late antiquity.     

Soil management in pre‐Hispanic raised field systems: Micromorphological evidence from Hacienda Zuleta,Ecuador

Soils‐based evidence derived from thin section micromorphology is used to explore contrasts in pre‐Hispanic and Hispanic arable land management practices associated with raised fields in an inter‐Andean valley of Ecuador. Differences in textural pedofeature characteristics suggest that, where they are found in the same locality, camellón systems were more intensively manured and cultivated than wachu systems. Both, however, were more intensively managed than traditional Hispanic arable fields. The importance of the camellón in pre‐Hispanic agriculture is emphasized by soils‐based evidence that highlights the efforts made to clear these fields of volcanic ash after the Quilotoa eruption of ca. A.D. 1280. This research suggests that, in an andosol context, pre‐Hispanic and Hispanic arable land management practices leave relict and fossil soil micromorphology features that can be used to interpret land use intensities. © 2002 Wiley Periodicals, Inc.     

Shell Middens,Cultural Chronologies,and Coastal Settlement on the Rhode River Sub‐Estuary of Chesapeake Bay,Maryland, USA

North America's Atlantic Coast has been a focus of human settlement and subsistence for millennia, but sea‐level rise, sedimentation, and other processes pose significant challenges for archaeological research. Radiocarbon dating of 31 shell middens near the Rhode River Estuary, Maryland provides an opportunity to evaluate human land use, settlement, and cultural chronologies on the Chesapeake Bay. Sixty calibrated radiocarbon dates on eastern oyster (Crassostrea virginica) shell and charcoal demonstrate that Native Americans, colonial, and historic peoples harvested oysters and other shellfish from at least 3200 years ago through the 19th century. The number of dated sites increases during the Late Woodland period after about 1000 cal yr B.P., a factor probably related to greater site visibility and preservation, as well as increased human exploitation of the watershed. Accumulation rates for five of the shell middens provide preliminary indications that some of the sites accumulated rapidly suggesting, along with other evidence, that many of the region's shell middens were logistical or perhaps seasonal camps. Our study demonstrates the importance of regional watershed surveys and radiocarbon dating programs to help build and refine cultural chronologies in coastal regions threatened by sea‐level rise and other processes.     

Consolidation in spatially random unsaturated soils based on coupled flow‐deformation simulation

This paper integrates random field simulation of soil spatial variability with numerical modeling of coupled flow and deformation to investigate consolidation in spatially random unsaturated soil. The spatial variability of soil properties is simulated using the covariance matrix decomposition method. The random soil properties are imported into an interactive multiphysics software COMSOL to solve the governing partial differential equations. The effects of the spatial variability of Young's modulus and saturated permeability together with unsaturated hydraulic parameters on the dissipation of excess pore water pressure and settlement are investigated using an example of consolidation in a saturated‐unsaturated soil column because of loading. It is found that the surface settlement and the pore water pressure profile during the process of consolidation are significantly affected by the spatially varying Young's modulus. The mean value of the settlement of the spatially random soil is more than 100% greater than that of the deterministic case, and the surface settlement is subject to large uncertainty, which implies that consolidation settlement is difficult to predict accurately based on the conventional deterministic approach. The uncertainty of the settlement increases with the scale of fluctuation because of the averaging effect of spatial variability. The effects of spatial variability of saturated permeability k_sat and air entry parameters are much less significant than that of elastic modulus. The spatial variability of air entry value parameters affects the uncertainties of settlement and excess pore pressure mostly in the unsaturated zone. Copyright © 2016 John Wiley & Sons, Ltd.     

The Geomorphological Context of Medieval Juslibol Castle in the Middle Reaches of the River Ebro,Spain

An interdisciplinary non‐invasive research strategy combining the analysis of archival documents, detailed geomorphological mapping, Quaternary stratigraphic studies, analysis of ceramics, and radiocarbon dating was designed to reconstruct the evolution of the Mezimegeer–Juslibol Castle, northeastern Spain. This fortress had great strategic importance in the siege and conquest of the nearby Islamic city of Saraqusta by the Christians in A.D. 1118. The castle and moat complex was built in the mid‐10th century. In the mid‐12th century, its rapid degradation began, as it is shown by this geoarchaeological study of the sediments in the moats. Its present state of decay is due to later erosion that is promoted by the unstable bedrock of Miocene gypsum, highly deformed gravels that form a Pleistocene fluvial terrace, and the environmental aridity.     

Soilscape and land‐use evolution related to drift sand movements since the bronze age in Eastern Jutland,Denmark

Quarry faces several kilometers long in the Glesborg area in Denmark show that Bronze Age farmers used a sustainable land‐use system. Despite nutrient‐poor soils, the Glesborg area was under a rotation system in which cropland alternated with grassland. Soil fertility was improved by the addition of household waste and probably also by locally obtained inorganic fertilizer. The soil surface was very stable, and local drift sand movement was limited. Toward the end of the Bronze Age, the landscape changed dramatically with the arrival of overwhelming amounts of drift sand, and farmsteads were abandoned. Subsequent land use on these poor fine sandy soils was no longer capable of maintaining a stable soil surface, and frequent erosion/sedimentation events of more local importance took place. The post‐Bronze Age landscape may have been mainly a shifting mosaic of heathland with some temporary arable fields and deflation/accumulation areas. This landscape persisted up to about 200 years ago, when afforestation programs started. © 2007 Wiley Periodicals, Inc.     

A high‐resolution pollen and geochemical analysis of late Holocene human impact and vegetation history in southern Cumbria,England

The historic era, which in Cumbria begins with the Roman invasion of AD 71, is a frequently neglected period in palaeoecological research, but its study can bring benefits in improving knowledge of landscape history and in understanding the significance and limitations of palaeoecological records. Pollen and geochemical data are presented for late Holocene records from Deer Dyke and Hulleter Mosses in southern Cumbria. The records show initially low levels of anthropogenic impact, followed by a phase of forest clearance and mixed agriculture from the 7th to 11th centuries AD. The timing of these clearances suggests that they were initially Anglo‐Saxon in origin, rather than Norse. Further clearances in the 16th century AD are interpreted as a response to monastic dissolution and late Tudor population pressures; the landscapes reached their contemporary form following extensive clearances in the 17th century AD. Silicon and titanium concentrations at Deer Dyke Moss were used to reconstruct past levels of atmospheric dust loading, which is broadly related to soil erosion. Geochemical influx was found to peak during periods of landscape transition rather than from established land use. This relationship with pollen data is thought to reflect the predominantly low levels of anthropogenic impact in the region, which changes as substantial woodland clearances during the 16th century AD and continuous land use pressure since then have greatly increased the supply of airborne dust. Copyright © 2008 John Wiley & Sons, Ltd.     

Soil Paleocatenas,Prehistoric Land Use,and Coastal Landscape Dynamics at Druridge Bay,Northeast England

Coastal erosion of sand dune systems along Druridge Bay, northeast England, has progressively exposed parts of the subdune mid‐Holocene landscape, including paleocatenas, indicating former soil hydrosequences with localized wetland habitats, and archaeological evidence of human activities and land use from the Late Mesolithic to the Romano‐British period. Archaeological investigations and pedostratigraphic studies of paleosols provide a unique spatial–chronological framework to interpret soil and land use change over several millennia in the context of a changing coastal environment. Evidence includes dating of archaeological remains, the stratigraphy, morphology and micromorphology of buried soils and sediments, and the palynology and radiocarbon dating of subdune peats. Early Bronze Age burial sites were preferentially located on well‐drained hillocks also used for grazing. Adjacent wetland depressions provided areas of marshy grassland and swamp over deep fen peat soils that started to develop c. 5435 cal. yr B.P. in response to a rising groundwater table stimulated partly by slow sea‐level rise. The backslopes of the paleocatena were occupied by imperfectly to poorly drained soils that supported open oak‐hazel woodland with evidence for progressive clearance and use for agriculture. Windblown sand started to accumulate on the study site sometime between 3930 and 3670 cal. yr B.P., well before the Little Ice Age date for dune formation suggested by previous researchers.     

Effect of spatial variability of cross‐correlated soil properties on bearing capacity of strip footing

Geotechnical engineering problems are characterized by many sources of uncertainty. Some of these sources are connected to the uncertainties of soil properties involved in the analysis. In this paper, a numerical procedure for a probabilistic analysis that considers the spatial variability of cross‐correlated soil properties is presented and applied to study the bearing capacity of spatially random soil with different autocorrelation distances in the vertical and horizontal directions. The approach integrates a commercial finite difference method and random field theory into the framework of a probabilistic analysis. Two‐dimensional cross‐correlated non‐Gaussian random fields are generated based on a Karhunen–Loève expansion in a manner consistent with a specified marginal distribution function, an autocorrelation function, and cross‐correlation coefficients. A Monte Carlo simulation is then used to determine the statistical response based on the random fields. A series of analyses was performed to study the effects of uncertainty due to the spatial heterogeneity on the bearing capacity of a rough strip footing. The simulations provide insight into the application of uncertainty treatment to geotechnical problems and show the importance of the spatial variability of soil properties with regard to the outcome of a probabilistic assessment. Copyright © 2009 John Wiley & Sons, Ltd.     

北京平原区地面沉降分布特征及影响因素

地面沉降是北京平原区主要地质灾害之一。文中采用永久散射体差分干涉测量(PS-InSAR)技术获取平原区地面沉降空间分布特征,基于GIS空间分析平台,将多种地面沉降影响因素分别与PS-InSAR获取的地面沉降场形变信息进行耦合研究,查明地面沉降与多种影响因素之间的响应关系。研究发现:(1)北京市地面沉降发育较为严重的地区主要出现在平原区东部、北部以及南部等地,存在多个沉降中心,最大沉降速率达到152mm/a,区域不均匀沉降现象明显,并且有连成一片的趋势。(2)地面沉降分布具有明显的构造控制特性,沉降区多位于几大活动断裂交接部位的沉积凹陷地区,与第四纪沉积凹陷十分吻合。地面沉降的发展趋势与活动断裂的走向具有明显的对应关系,在有活动断裂通过的区域,地面沉降剖面线上表现出明显的转折或突变,断裂两侧区域不均匀沉降十分明显。(3)地面沉降分层沉降量与对应层位上黏性土占比呈正比例关系,其空间分布特征及变化趋势与平原区的地层结构及可压缩黏性土层厚度具有很好的一致性,沉降范围整体由北西向的单一结构区向南东方向的多层结构区扩张。沉降速率大于50 mm/a的沉降区大多分布在黏性土层厚度大于100 m的地区,几大沉降中心与黏性土层厚度较大地区吻合较好。(4)第二承压含水层(顶底板埋深100~180 m)地下水开采对地面沉降影响最大,沉降中心与该层位地下水位降落漏斗区高度吻合,是地面沉降的主要贡献层位。     

漓江流域表层土壤水分物理性质空间异质性

为了解漓江流域土壤水分空间变化特征及其影响因素,基于2'经纬网格,采用地统计学方法对该流域表层（0~10 cm）土壤水分物理性质的空间变异进行分析。结果表明:从空间结构比上,漓江流域表层土壤含水量、容重、最大和最小持水量均具有高度的空间自相关性（各指标空间结构比均大于0.87）,且其空间分布趋势基本一致,由流域上游向中下游逐渐变化。土地利用对流域表层土壤水分物理性质及其空间变异具有显著影响。受时间尺度和土地利用类型等因素的影响,漓江流域表层土壤含水量相比其他土壤水分物理性质,其空间异质性由随机引起的空间变异增加,空间自相关减小,为0.87;而土壤容重最大,为0.92。相关结果对于漓江流域土壤水分动态模拟与预测研究具有一定参考价值。     

A 1286‐year hydro‐climate reconstruction for the Balkan Peninsula

We present a June–July drought reconstruction based on the standardized precipitation index (SPI) for the Balkan Peninsula over the period 730–2015 CE. The reconstruction is developed using a composite Pinus heldreichii tree‐ring width chronology, from a high‐elevation network of eight sites in the Pindus Mountains in northwest Greece, composed of living trees and relict wood. The dataset includes the ring width series of Europe's currently oldest known living tree, dendrochronologically dated to be more than 1075 years old. The spatial coverage of the reconstruction is improved by using an averaged gridded SPI data target derived from a response field that is located north of the study region. Justification for this approach includes the remoteness of instrumental data, the spatial variability of precipitation and synoptic scale circulation patterns. Over the past 1286 years, there have been 51 dry and 43 pluvial events. The driest year during the 1286‐year‐long period was 1660 and the wettest year was 1482. Comparison with shorter reconstructions and documentary evidence validates the new reconstruction, and provides additional insight into socioeconomic impacts and spatial patterns of extreme events. Fifty‐nine of 72 previously undescribed extremes occurred prior to the 17th century. The new reconstruction reveals long‐term changes in the number of extremes, including substantially fewer drought and pluvial events in the 20th century. Additional tests on the long‐term effects of age structure, replication and covariance changes support the heteroscedastic nature of the reconstructed hydro‐climatic extremes.     

Modeling of granular bed‐stone column‐improved soft soil

The present study pertains to the development of a mechanical model for predicting the behavior of granular bed‐stone column‐reinforced soft ground. The granular layer that has been placed over the stone column‐reinforced soft soil has been idealized by the Pasternak shear layer. The saturated soft soil has been idealized by the Kelvin–Voigt model to represent its time‐dependent behavior and the stone columns are idealized by stiffer Winkler springs. The nonlinear behavior of the granular fill has been incorporated in this study by assuming a hyperbolic variation of shear stress with shear strain as in one reported literature. Similarly, for soft soil it has also been assumed that load‐settlement variation is hyperbolic in nature. The effect of consolidation of the soft soil due to inclusion of the stone columns has also been included in the model. Plane‐strain conditions are considered for the loading and foundation soil system. The numerical solutions are obtained by a finite difference scheme and the results are presented in a non‐dimensional form. Parametric studies for a uniformly loaded strip footing have been carried out to show the effects of various parameters on the total as well as differential settlement and stress concentration ratio. It has been observed that the presence of granular bed on the top of the stone columns helps to transfer stress from soil to stone columns and reduces maximum as well as differential settlement. Copyright © 2007 John Wiley & Sons, Ltd.     

One‐dimensional contaminant transport through a deforming porous medium: theory and a solution for a quasi‐steady‐state problem

Contaminant migration through soil is usually modelled mathematically using the dispersion–advection equation. This type of model finds application when planning the remediation of contaminated land, predicting the movement of polluted groundwater and designing engineered landfills. Usually the analysis assumes that the porous media through which the contaminant migrates is stationary. However, the construction of landfills on clay soils means that the soil beneath the landfill will undergo time‐dependent deformation as the soil consolidates. To date, there are no published data on the effect a deforming porous media may have on contaminant transport beneath a landfill; indeed, there appears to be no theory of contaminant migration through a deforming soil. In this paper, a one‐dimensional theory of contaminant migration through a saturated deforming porous media is developed based on a small and large strain analysis of a consolidating soil and conservation of contaminant mass. By selection of suitable parameters, the new transport equation reduces to the familiar one‐dimensional dispersion–advection equation for a saturated soil with linear, reversible, equilibrium controlled sorption of the contaminant onto the soil skeleton. Analytic solutions to a quasi‐steady‐state contaminant transport problem for a deforming media are presented, and a preliminary assessment made of the potential importance of soil deformation on the results of a contaminant migration analysis. Copyright © 2000 John Wiley & Sons, Ltd.     

Anthropogenic influences on Zuni agricultural soils

Farmers in the Zuni area of the semiarid American Southwest have successfully cultivated maize and other crops for over three millennia without using artificial fertilizers. Zuni agricultural fields are among the oldest, more or less continuously cultivated areas in the United States. Traditional Zuni agriculture is based on runoff farming, a system whereby runoff and organic‐rich sediment generated in small watersheds are captured and directed onto fields for crop use. We conducted a study to compare soil properties associated with paired and unpaired cultivated, abandoned, and uncultivated fields to evaluate the long‐term effects of cultivation on soil quality. Sampling and analytical methods of this research are especially applicable to geoarchaeological studies of anthropogenic effects on soil fertility and agricultural sustainability in ancient and traditional historical farming systems. Results of the Zuni soil study indicate that cultivation has altered some soil properties, including bulk density, organic carbon, total nitrogen, and C:N ratios in paired fields, but there is no indication that agricultural soils are degraded. This assessment supports the perception of Zuni farmers that long‐term cultivation has not caused a decline in agricultural productivity. © 2005 Wiley Periodicals, Inc.     

土壤入渗特性的空间变异规律及其变异源

以封丘地区典型的4种土地利用类型(传统耕作地、免耕地、金银花地和杨树林地)为例,系统研究了不同土地利用方式下土壤入渗特性的空间变异强度、空间变异结构及其主要变异源。结果表明,频繁的耕作会降低土壤异质性,弱化土壤特性空间变异结构,扰动较小的免耕地和金银花地的土壤入渗特性则具有相对明显的空间变异结构,扰动最小的杨树林地土壤的入渗特性具有最为明显的空间变异结构和最小的变程。容重、有机质含量和初始含水量是耕作地入渗的最主要变异源,初始含水量则是金银花地入渗的唯一显著性变异源;杨树林地入渗变异的主要变异源是有机质和初始含水量;影响免耕地入渗特性变异的变异源并不显著。在有些情况下,水温也可能成为入渗特性空间变异研究的重要干扰因素。     

Assessment of the spatio-temporal distribution of soil properties in East Kolkata wetland ecosystem (A Ramsar site: 1208)

The present investigation was made to characterize spatial and temporal variations in soil properties and to evaluate possible differences that could be dependent on the tannery effluent discharges, municipal sewage discharges, vegetation cover, soil settlement rate, crop rotation, etc. Soil total organic matter (TOM), cations like, Sodium (Na), Ammonium (NH₄), Potassium (K), Calcium (Ca) and Magnesium (Mg) contents in the bank soils and bottom sediments were recorded from seven different characteristic sites in East Kolkata wetland ecosystem, a Ramsar site (Ramsar site No. 1208). The profile maps were constructed by geostatistical methods to describe the spatial distribution as well as temporal variations of all the factors to identify the influences of composite wastewaters. The work was initiated to identify causes and consequences of the waste dumping in the concerned region for the past hundred years and thereby to suggest necessary precautionary measures to prevent further loss of soil quality.     

Wind erosion and intensive prehistoric agriculture: A case study from the Kalaupapa field system,Moloka'i Island,Hawai'i

Wind erosion is a major problem for modern farmers, a key variable affecting nutrient levels in ecosystems, and a potentially major force impacting archaeological site formation; however, it has received scant consideration in geoarchaeological studies of agricultural development compared with more easily quantifiable environmental costs, such as vegetation change or fluvial erosion. In this study, soil nutrient analysis is used in the Kalaupapa field system, Moloka'i Island, Hawai'i, to detect an increase in wind erosion attributable to intensive agriculture following the burning of endemic forest. This practice began on a small scale in the 13th century A.D., expanded around cal A.D. 1450–1550, and continued until the near total abandonment of the fields after European contact in the 18th century. Nutrients that naturally occur in high amounts in coastal windward areas due to the long‐term, cumulative effect of sea spray were especially impacted. However, thanks to the unique landform of the Kalaupapa Peninsula, nutrient depletion in windward areas was offset by downwind enrichment and likely contributed to the long‐term sustainability of the system as a whole. Future research on tropical and arid agriculture should consider the cumulative environmental cost of increased eolian erosion attributable to anthropogenic landscape modification. © 2007 Wiley Periodicals, Inc.