Feature Environmental geophysics: a site characterization tool for urban regeneration in the post-mining era

The closure and decay of industrial activity involving mining, chemical or light industrial operations has scarred the landscape of urban areas. The Government has major initiatives in urban regeneration to remediate these 'brown-field sites'.     

Archaeological geology of the Rustad Quarry site (32RI775): An early archaic site in Southeastern North Dakota

At The Rustad Quarry Site (32RI775), in southeastern North Dakota, Early Archaic artifacts, bison bone, and hearth features were found in the lowest of three Boroll-like buried soils formed in alluvial fan sediments. Alluvial fan sediments were deposited from 8000 to 4925 B.P., and were then buried by eolian sand. The alluvial fan sediments (mudflows) bury lacustrine sediments (Sherack Formation deposited from 9900 to 9500 B.P. in Glacial Lake Agassiz II), both of which overlie a Moorhead Phase fluvial terrace deposited from 10,900 to 9,900 B.P. Cultural remains were associated with five radiocarbon ages, three on archaeological charcoal (7180 B.P., 7240 B.P., and 7550 B.P.) and two on organic carbon from two welded A-horizons containing the cultural remains (7370 B.P. and 7675 B.P.). A well-developed Aquoll-like soil formed in the lacustrine sediments from 9500 to 8000 B.P. Soil morphology and chemistry of the Boroll-like fan soils, the Aquoll-like lacustrine soil, and other Boroll-like soils formed in eolian and deltaic sediments nearby suggest a subhumid, cool continental climate with riparian woodland and mixed prairie vegetation at the site and surrounding area from 11,400 B.P. to the present. This partially contradicts paleoenvironmental reconstruction from pollen sites nearby that suggest the area was covered by a closed canopy spruce forest from terminal late-Pleistocene to 10,000 B.P. Alluvial fan formation and eolian activity on the adjacent Sheyenne Delta occurred from 8000 to 5000 B.P., which indicates greater landscape instability and drier conditions during the mid-Holocene (Altithermal).     

Subsurface geophysics applied to archaeological investigation of Thabudeos Roman fortress (Biskra,Algeria)

Tahouda, former Roman Thabudeos, is situated 400 km south of Algiers (Algeria). It is one of the fortresses belonging to Roman south defense line in North Africa. This region is archaeologically very poorly known except for surface remains. The geophysical survey formed part of a wider research project designed to record and assess the landscape context of the longest Roman defense line in North Africa. We present the geophysical mapping and imaging using electric resistivity tomography and electromagnetics to help in investigating the subsurface properties of the region. Data were obtained using: (1) Saris resistance meter with up to 25 electrodes spaced at 2 m intervals and lines up to 50 m long. A total of 11 lines was obtained. (2) Geonics EM31, in two dipole configuration modes with 16 lines up to 100 m sampled every meter. These methods prove to be very powerful tools to give insight and locate the anthropologic remains from the surface to a depth of 6 m and outline their geometry. The results obtained by the two methods are consistent above the main remains like walls and rooms.     

Archaeoseismological investigation of the ancient Ayla site in the city of Aqaba,Jordan

Many tens of severe earthquake damage patterns were revealed at the ancient city of Ayla. The seismic deformation patterns are of various types, including systematic tilting of walls, systematic shifting and rotation of wall fragments and individual stones, arch deformations and joints crossing two or more stones. Features of later repair, supporting walls and secondary use of building stones suggest that the damage patterns can be explained by two historical devastating earthquakes: (I) revealed in the constructions built during the late Rashidun period (644–656 A.D.); (II) revealed in the structures restored and/or built during the Fatimid period (1050–1116 A.D.). The maximum observed intensity of both earthquakes at the studied site was not less than IX (EMS98 scale). The sources of the seismic events were probably the Dead Sea Transform and Wadi Araba Faults that cross the site obliquely. The last 1995 Nuweiba earthquake with maximum observed intensity VIII has also left its clear traces in the excavated ancient Ayla buildings. The severity of the destruction was significantly increased because of site effects.     

Hydrogeological investigation of a groundwater contamination site in southern Taiwan

 Groundwater samples taken from wells adjacent to a food machinery manufacturing plant in southern Taiwan indicate that there is a serious phenolic contamination. To understand the hydrogeological properties, and to prepare for remedial action, a series of hydrogeological investigations were conducted. Investigative work included collecting background information, analyzing existing data, measuring the groundwater, and conducting a slug test, pumping and recovery test, aerial photography analysis and electrical resistivity survey. Results from these investigations show that the local groundwater aquifer may be classified as an unconfined or confined formation, depending on the thickness of the interbedded clay layer. The direction of local groundwater flow is from southwest to northeast, with high transmissivity. The contaminant moves much more slowly than the average groundwater velocity, and it is limited to an area centered around the plant. The local geology of the contaminated area exhibits significant heterogeneity; it is not likely to have been formed by natural sedimentation. Data from the field aerial photography analysis and electrical resistivity survey also suggest that this shallow formation may result from artificial back-filling. Received: 1 September 1994 · Accepted: 28 December 1995     

古马岭金矿床地质、地球物理、地球化学特征

本文总结了古马岭金矿地质、地球物理、地球化学特征,确定了金矿体和金矿化蚀变带的找矿标志。     

A comparison of field and laboratory analytical methods for radon site investigation

Soil-gas radon measurements provide a valuable tool in assessing probable indoor radon levels on a regional basis. However, in Great Britain, seasonal weather changes can cause large changes in soil-gas radon concentration. Although this does not significantly constrain systematic radon potential mapping programmes, it does cause difficulties in responding to ad-hoc requests for site-specific radon investigations. The relationship between soil-gas radon and gamma spectrometry measurements made in the field with radon released from a representative sample of soil in the laboratory has been investigated as part of a program to develop a method of radon potential mapping and site investigation which can be used at any time of the year. Multiple soil and soil-gas samples were collected from sites underlain by bedrocks with widely varying radon potentials. For each geological unit, sites both free of and covered by glacial drift deposits were sampled. Soil and soil-gas samples were taken at the same depth of 60–100 cm. The effectiveness of these radon site investigation procedures has been evaluated by studying the relationship between the soil-gas radon, gamma spectrometry and radon emanation data with an independent estimate of the radon risk. The geologic radon potential (GEORP), which is the proportion of existing dwellings which exceed the UK radon Action Level (200 Bq m⁻³) for a particular combination of solid and drift geology within a defined geographic area, has been used for this study as the independent estimate of radon risk. Soil-gas radon, radon emanation and eU (equivalent uranium by field γ spectrometry) are all good geochemical indicators of radon risk (GEORP) in Derbyshire but only soil-gas radon correlates significantly with GEORP in Northamptonshire. Radon in soil gas discriminates more effectively between sites with different radon potential in Northamptonshire if soil permeability is also taken into account. In general, measurement of soil-gas radon in the field provides the most universally applicable indicator of radon potential. If soil-gas radon concentrations cannot be determined because of climatic factors, for example when the soil profile is waterlogged, measurement of radon emanation in the laboratory or measurement of eU can be used as radon potential indicators in some geological environments. This applies particularly in areas where the soil composition rather than the composition and permeability of the underlying rock or superficial deposits are the dominant controls of radon potential. It appears, therefore, that it may be necessary to use different radon site investigation methods according to the specific factors controlling radon emanation from the ground. In some cases no method will provide a reliable indicator of radon risk under unfavourable climatic conditions.     

Archaeological site distribution by geomorphic setting in the southern lower Cuyahoga River Valley,northeastern Ohio: Initial observations from a GIS database

In this study, we compiled unpublished archival documentation of archaeological site locations from the southern part of the Cuyahoga River Valley in northeastern Ohio, USA, registered at the State of Ohio Historic Preservation Office into a Geographic Information Systems (GIS) database. Using digitized soil shapefiles to generate a geomorphic data layer, we assessed the spatial and temporal distribution of 79 known archaeological sites by landform association. This digital compilation indicates that Woodland period, Late Prehistoric, and Historic sites occur in most geomorphic settings along the river valley. In contrast, Paleoindian and Archaic sites only occur on Wisconsinan cut terraces and in upland interfluve settings, indicating that most of these documented sites are in primary contexts and have not been reworked. We discuss the distribution of archaeological sites in the study region as a function of various factors, including cultural activities, taphonomic processes, landform development, and the nature and extent of the original archaeological surveys. Observed spatial patterns of known sites clearly reflect local geomorphological controls; artifactual contexts from the earlier prehistoric periods are underrepresented in the database. We conclude that additional site surveys, as well as the excavation and documentation of new sites in this part of Ohio, are required to understand local prehistoric economies and to ascertain patterns of culturally mediated land use. © 2004 Wiley Periodicals, Inc.     

某地块污染调查及二氯甲烷在土壤和地下水中的分布特征

以某生物医药企业地块为研究对象,结合企业生产历史,识别该地块疑似污染区域以及关注的污染物,通过布设土壤及地下水现场采样点进行现场和实验室测试,研究土壤及地下水中监测因子的含量及分布特征,特别是对二氯甲烷的污染源及其在土壤和地下水中的分布特征进行分析,指出由于地层特征和多种有机污染物的影响,土壤中二氯甲烷的含量未超过国家标准,但在地下水中含量异常高;分析地层对二氯甲烷在土壤和地下水中垂向和侧向迁移的影响,为下一步污染防控提供依据。     

Magnetic and seismic refraction survey for site investigation of an urban expansion site in Abha District,Southwest Saudi Arabia

Arabian Journal of Geosciences - Ground magnetic and seismic refraction survey is carried out on an urban extension site in the southwest of Ahud Rufeidah town, southwest Saudi Arabia. The purpose...     

Geochemical and mineralogical investigation of domestic archaeological soil features at the Tiel-Passewaaij site,The Netherlands

Archaeological soil features can be defined as areas of staining in ancient cultural soil horizons and are frequently used in surveys to locate sites and activity areas. Visual observation of these features, however, provides only limited information on their origin and the processes leading to their formation and this limits site interpretation. This paper presents the results of geochemical and mineralogical analyses of domestic archaeological soil features in order to assess their composition, formation pathway and origin. The greenish soil features studied here belong to a house plan from a Roman farmhouse located at the Tiel-Passewaaij site in the Netherlands. The soils were investigated using a range of techniques, including X-ray Fluorescence (XRF) spectroscopy, sequential soil extractions, Fourier-transformed infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD) and microprobe analysis. The results indicate that the studied soil features can chemically be distinguished from off-site soils e.g. based on their phosphate and carbonate content. Mineralogical analysis of aggregate samples from soil features further reveal that quartz and feldspar minerals are coated with Ca–Fe–P phases that closely resemble anapaite and mitridatite mineral forms. The formation of these mineral phases probably resulted from periodic reductive dissolution of Fe-oxide phases and subsequent precipitation of Fe–P phases, with inclusion of Ca from anthropogenic carbonates or groundwater. The combined presence of (Ca)-carbonates, P-phases and some anthropogenic trace elements (Cu, Zn) suggests that the greenish soil features stem from manure inputs.     

酶诱导碳酸钙沉淀加固遗址土动力特性试验研究

中国西北地区地震频发,土遗址长期受到地震活动的不利影响。为了研究酶诱导碳酸钙沉淀技术（EICP）加固遗址土的动力特性,对1.55、1.65、1.75 g/cm³这3种初始干密度的遗址土进行EICP处理,并设置未经EICP处理的对照组。开展了不同围压、振动频率下的动三轴试验。结果表明：在相同动应力作用下,相比对照组,试验组的动应变更小,耗散的能量更少,阻尼比更小;在EICP加固后,随着干密度、围压、振动频率增大,可以降低动应变的产生,但这种效果依次减弱。动本构关系符合Hardin模型,干密度、围压、振动频率对模型参数a（动弹性模量）的影响程度逐渐减小;微观分析发现,EICP加固后,碳酸钙沉淀在土颗粒表面附着,填充孔隙,并与土颗粒相互胶结成致密结构,土体结构强度增强。     

Field investigation of the natural attenuation and intrinsic biodegradation rates at an underground storage tank site

 Contamination of groundwater by petroleum-hydrocarbons is a widespread environmental problem. Natural attenuation is a passive remedial approach to degrade and dissipate contaminants in soil and groundwater. In this study, a mass flux approach was used to calculate the contaminant mass reduction and field-scale decay rate at a gasoline spill site. The mass flux technique is accomplished using the differences in total contaminant mass flux across two cross sections of the contaminant plume. The mass flux calculation shows that up to 88% of the dissolved BTEX (benzene, toluene, ethylbenzene, and xylene isomers) removal was observed by natural attenuation processes. The efficiency of intrinsic biodegradation was evaluated by the in situ tracer method. A first-order decay model was applied for the natural attenuation and intrinsic biodegradation rate calculation. Results reveal that intrinsic biodegradation process was the major cause of the BTEX reduction among the natural attenuation mechanisms, and iron reduction was the dominant biodegradation pattern within the plume. Approximately 87% of the BTEX removal was caused by intrinsic biodegradation processes. The calculated BTEX natural attenuation and intrinsic biodegradation rates were 0.24 and 0.16% l/day, respectively. Results suggest that natural attenuation mechanisms can effectively contain the plume, and the mass flux method is useful in assessing the efficiency of the natural attenuation. Received: 6 December 1999 · Accepted: 11 July 2000     

直推钻探技术在污染场地调查中的应用现状研究

钻探技术是污染场地调查中唯一可直接获取地层样品的科学手段。其中直推钻探技术具有无冲洗介质、机动灵活、推进速度快、样品干扰小等优点。本文在已有国内外研究基础上,对比分析了西班牙TEC15和美国7822DT两类直推钻机的结构、推进工艺特点,后者具有较高静推进力和起拔力;研究了单管和双管两种直推钻具的结构组成和取样过程,并指出由于单管内设PVC取样套管,可有效保持土样的完整性,效率较高;分析了核磁共振(NMR)、土体水力测试(HPT)、膜界面探测(MIP)的技术原理和设备组成,MIP对污染物三维浓度探测具有更大技术优势;分析了国内直推钻探技术与设备的发展状况,并结合我国污染场地的地质条件和研究现状,指出能够实现精准控制的推进钻探和原位检测一体化装备和技术验证是主要的发展趋势。     

Variability of the water stock dynamics in karst: insights from surface-to-tunnel geophysics

Hydrogeology Journal - A hydrogeophysical field experiment was conducted on a karst hydrosystem in the south of France to investigate groundwater transfer and storage variability at a scale of a...     

Multiple-methods investigation of recharge at a humid-region fractured rock site,Pennsylvania, USA

Lysimeter-percolate and well-hydrograph analyses were combined to evaluate recharge for the Masser Recharge Site (central Pennsylvania, USA). In humid regions, aquifer recharge through an unconfined low-porosity fractured-rock aquifer can cause large magnitude water-table fluctuations over short time scales. The unsaturated hydraulic characteristics of the subsurface porous media control the magnitude and timing of these fluctuations. Data from multiple sets of lysimeters at the site show a highly seasonal pattern of percolate and exhibit variability due to both installation factors and hydraulic property heterogeneity. Individual event analysis of well hydrograph data reveals the primary influences on water-table response, namely rainfall depth, rainfall intensity, and initial water-table depth. Spatial and seasonal variability in well response is also evident. A new approach for calculating recharge from continuous water-table elevation records using a master recession curve (MRC) is demonstrated. The recharge estimated by the MRC approach when assuming a constant specific yield is seasonal to a lesser degree than the recharge estimate resulting from the lysimeter analysis. Partial reconciliation of the two recharge estimates is achieved by considering a conceptual model of flow processes in the highly-heterogeneous underlying fractured porous medium.     

航空物探飞机典型飞行状态下振动特性研究

飞机振动对航空重力或重力梯度测量而言十分重要,为充分了解飞机振动特性,并为相关仪器系统量程和结构设计提供参考和依据,笔者针对Y-12和Cessna 208固定翼飞机典型航空物探飞行状态下的振动情况进行了大量测量和深入分析。研究结果表明:飞机地板上的振动主要由发动机引起,振动能量随螺旋桨转速呈倍频规律分布,该倍频的基频为螺旋桨转速基频乘螺旋桨叶片数,飞机在飞行状态下的振动为典型的周期性振动信号。