Results Of Geophysical Survey Research Articles

Imageamento Elétrico 3D em área contaminada por hidrocarbonetono polo industrial de Cubatão - SP

This work presents the results of geophysical surveys performed over an oil contaminated site in the Polo Industrial de Cubatao - Sao Paulo. The aim is to characterize geoelectrical signatures associated to hydrocarbon presence in order to delimit and calculate the volume of the contaminated area. For this study were used Vertical Electrical Sounding (VES) and 3D Electrical Imaging for characterization of geology and geoelectrical response of the contaminant. The results showed that the hydrocarbon presence is associated to conductive anomalies due to products from biodegradation. The conductive anomalies are disseminated over the area, totalizing 1365.3 m3 volume. This volume, however, corresponds only to the residual phase contaminants, since it was not possible to map free-phase hydrocarbons.

Settlement History and Urban Planning at Zincirli Höyük, Southern Turkey

This paper presents results of geophysical survey at Zincirli Höyük, a 40-hectare site in southern Turkey dating to the early first millennium bc. The site’s lower town offers ideal circumstances for magnetic gradiometry, and survey results from this area, combined with the results of excavations from the 1890s on the central high citadel, now reveal a nearly complete plan of the ancient city. The results therefore present a unique opportunity to explore the relationship between the production of urban space and the social and historical forces that drove it. Our evidence from Zincirli strongly suggests a pattern of distributed authority in creating the built environment of the city, whereby the king and his administrators planned and constructed the circular walls, streets, and citadel, but according to which individual elite households were probably left to plan and build their own residential compounds. The spatial relationships of these features raise important questions regarding social organization at Iron Age Zincirli. The results also offer a model for understanding the unique spatiality of new cities that were founded throughout Syria and Anatolia during the early first millennium and highlight the relationship of Zincirli to these and other planned cities of the ancient Near East.

Moai, quarries and roads. Experiences and results of geophysical survey on Rapa Nui (Easter Island)

Rapa Nui or Easter Island is home to some of the most recognisable archaeological monuments in the world, the iconic monolithic moai statues. The island is situated in the Eastern Pacific, approximately 3 000 km west of the coast of Chile and 2 500 km from Tahiti. The isolated location of the island is due in part to its formation by a series of volcanic eruptions. The differing stone types formed as a result of this volcanic activity are a key element in the monumental structures such as the...

Temporal geophysical signatures from contaminant-mass remediation

We have previously documented changes in bulk electrical conductivity, self-potential (SP), and ground-penetrating-radar (GPR) reflections in a field setting caused by biogeochemical transformations of hydrocarbon-contaminated media. These transformations are associated with hydrocarbon biodegradation. The results of surface geophysical surveys acquired in 1996, 2003, and 2007 document changes in geophysical signatures associated with removing hydrocarbon mass in the contaminated zone. Initial investigations in 1996 showed that relative to background, the contaminated area was characterized by higher bulk electrical conductivity, positive SP anomaly, and attenuated GPR reflections. Repeated surveys in 2003 and 2007 over the contaminated area showed that in 2007, the bulk electrical conductivityhad reverted to near-background conditions, the positive SP anomaly became more negative, and the zone of attenuated GPR reflections showed increased signal strength. Removal of hydrocarbon mass in the vadose zone over the plume by a soil vapor-extraction system installed in 2001 was primarily responsible for the changing geophysical responses. Although chemical data from groundwater showed a [Formula: see text]-thick con-ductive plume in 2007, the plume was not imaged by elec-trical resistivity. Forward modeling suggests that apparent bulk electrical conductivity of the saturated zone plume has to be three to five times higher than background values to be imaged by electrical resistivity. We suggest that removing hydrocarbon-contaminant-mass reduction by natural or engineered bioremediation can be imaged effectively by temporal geophysical surveys.

The Assimilation of Marine Geophysical Data into the Maritime Sites and Monuments Record, Northern Ireland

Northern Ireland has been subject to significant maritime influences throughout its known 9,000-year human history. In 1997, the University of Ulster, in partnership with the Environment and Heritage Service, embarked on a program of seabed mapping in an attempt to record the submerged and buried archaeological resources. To date, the geophysical research program has imaged about 80 19th- and 20th-century wrecks and about 100 targets of further “archaeological potential.” One method of integrating the results of geophysical surveys into the Maritime Sites and Monuments Record (SMR) is the use of the classification scheme CEBESSt, an alphanumeric wreck-site classification scheme based upon six site-specific variables: Composition of hull, Energy of wreck environment, Burial, Exposure, Structural integrity, and Substrate type, with t corresponding to time (the year of wrecking, if known). The classification is designed for use within a database scheme that allows for interrogation through character recognition and pattern matching.

Anglo-Saxon and Earlier Settlement near Drayton Road, Sutton Courtenay, Berkshire

Since E. T. Leeds' excavations of the Anglo-Saxon settlement at Sutton Courtenay in the 1920s and 1930s, aerial photographs revealing large timber buildings, as well as finds of metalwork and coins have suggested that the settlement was more extensive and of higher status than Leeds had imagined. This report reviews this evidence and describes the results of fieldwalking, geophysical survey and small-scale excavation which have provided further details of the Anglo-Saxon settlement, and uncovered one of the timber buildings. It has also revealed features pre-dating the Anglo-Saxon occupation: Neolithic pits and an oval barrow—perhaps related to a nearby cursus—a Late Bronze Age burial, an Early Iron Age settlement and a Roman field system.

Application of geophysics to North American prehistoric sites

William J. Johnson and Donald W. Johnson, members of the US-based Archaeology and Geophysics Consortium, explain how North America has some catching up with Europe to do in applying geophysical methods in archaeological investigations. Archaeological geophysics, sometime called remote sensing by archaeologists, is the measurement of geophysical properties at the ground surface to create images of the subsurface that can be interpreted by a geophysicist and archaeologist working together to identify subsurface features of cultural origin. As such, geophysics is a tool to infer the presence of cultural features before excavations actually take place. Geophysical measurements also allow for obtaining a continuity of subsurface information that compliments the detailed point information from shovel tests or unit excavations. The geophysics can then provide context to the excavations made by the archaeologists. Geophysical measurements are not routinely obtained at North American prehistoric sites. This situation contrasts with European practice, where geophysical studies are a routine part of archaeological investigations. A contributing factor for this situation is the subtlety of North American targets. There is a perception by many archaeologists that because prehistoric peoples in North America did not routinely leave massive stone foundations, there is little to image with geophysics. Another factor is that professional geophysicists have not been involved with the majority of the available case histories. Even the case histories published at the North American Database of Archaeological Geophysics (NADAG) at the University of Arkansas (http:// www.cast.uark.edu/nadag/) are not of uniform quality. Of the approximately 80 results of geophysical surveys presented for prehistoric sites by NADAG, more than three quarters do not demonstrate representative results and/or appropriate procedures. Nevertheless, within this group there are also some excellent case histories. Especially worthy of note are recent studies conducted at the Hollywood Mounds site in Tunica County, Mississippi by the University of Mississippi (Johnson et al., 2000); the Mit-tutta-hang-kush Village (Fort Clark State Historic Site, 32ME2), ND presented by Kvamme (2001); and the Double Ditch Indian Village State Park (32BL8) presented by Kvamme (2002). Many of the results of the geophysical surveying appear to indicate promising results, but have not been ground-truthed, such as the work at the Greenbriar site in Arkansas (Johnson et al., 1999). The work by the University of Arkansas at the Toltec Mounds (Lockhart, 2001) shows interesting results that could also benefit from additional ground truthing.

Integrated geophysical surveys at the archaeological site of Tindari (Sicily, Italy)

The results of geophysical survey carried out at the archaeological site of Tindari, located 70 km west-north-west of Messina (Sicily, Italy), are presented and discussed. The site is one of the most important archaeological sites, about 90 ha large, on the north-eastern side of Sicily and it was one of the last Greek settlements in Sicily. Keeping in mind the vastness of the site, according to the archaeologists an area, of about 1200 m 2 was selected, for a geophysical survey. Electrical resistivity tomography (ERT), including induced polarization (IP) measurements, and seismic refraction tomography were applied in the course of geophysical exploration in the area. The objective of this preliminary geophysical investigation was to verify the effectiveness of the technique for a spatial definition of the buried archaeological structures (mostly walls, columns, etc.) to determine their characteristics and to study the presence of collapsed columns within the zone of archaeological interest, in view of their application in the rest of the site, that, for obvious reasons, could not be entirely excavated in brief times. The geophysical data, visualized in 3D space, revealed a distribution of low-contrast shallow anomalies that indicate the presence of different types of buried structures in the surveyed area. Also, the probable accumulations of collapsed columns could be determined. These results confirm the hypothesis of a large northern extension of the archaeological site and provide useful information to design a more efficient excavation plan.

The cohors equitata fort at Tihău-Cetate, Romania: the results of geophysical survey and other research

The <i>cohors equitata</i> fort at Tihău-Cetate, Romania: the results of geophysical survey and other research

Detailed investigation of preserved maar structures by combined geophysical surveys

The detection of completely preserved maar structures is important not only for underground mapping but also for paleoclimate research because laminated maar lake sediments may contain a very detailed archive of climate history. Objective evidence for the existence of such structures can only be provided by geophysics and boreholes. The combination of gravity and magnetic ground surveys appears to be an excellent tool to detect and identify buried maar structures. Their prominent properties are an almost circular gravity minimum corresponding to a crater filled with limnic sediments of low density, and a magnetic anomaly caused by a pyroclastic or basaltic body in the diatreme which indicates the volcanic character. Seismic measurements provide the most detailed information about the internal structure of the maar sediments. Zones of low seismic reflectivity and very low density represent sediments of the late maar-lake period. The early lake period is indicated by debris flow deposits and turbidites represented by seismic reflectors. The seismic sections clearly reveal the bowl-like structure of the maar. Outside this bowl-like structure, there are only a few reflections, which represent the basement. Taking into account the shape of the gravity anomaly, seismic information allows geometrical modelling of the maar structure. Optimal drilling sites can be selected based on the results of geophysical surveying. Comparing the results of combined geophysical surveys above two maar structures of different ages yields a marked similarity in their geophysical pattern.

Geochemical, Microbiological, and Geophysical Assessments of Anaerobic Immobilization of Heavy Metals

Bioremediation methods that precipitate contaminants in situ as solid (mineral) phases can provide cost-effective options for removing dissolved metals in contaminated groundwater. The current field-scale experiments demonstrate that indigenous bacteria can be stimulated to remove metals by injection of electron-donating substrates and nutrients into a contaminated aquifer. Groundwater at the investigation site is aerobic and contains high levels of lead, cadmium, zinc, copper, and sulfuric acid (pH = 3.1) derived from a car-battery recycling plant. During the experiments, lead, cadmium, zinc, and copper were almost completely removed by precipitation of solid sulfide phases, as pH increased from 3 to ∼ 5 and Eh dropped from +400 mV to −150 mV. X-ray and transmission electron microscopy (TEM) analyses of filtered material from the treated groundwater indicated the presence of newly formed nanocrystalline metal sulfides. Genetic sequencing indicated that the principal species of sulfate-reducing bacteria involved in the bioremediation process was Desulfosporosinus orientis. Geochemical modeling shows that oxidation of added substrates and subsequent bacterial sulfate reduction produced desired geochemical conditions (i.e., decreasing Eh and increasing pH) for the precipitation and sorption of metal sulfides. Geophysical survey results suggest that bioremediation lowers electrical conductance of groundwater and possibly increases the magnetic susceptibility of porous media. This study demonstrates that integrated geochemical, geophysical, and microbiological analyses, combined with theoretical modeling, can successfully track and predict the progress of subsurface bioremediation.

Crustal structure in Tengchong Volcano-Geothermal Area, western Yunnan, China

Based upon the deep seismic sounding profiles carried out in the Tengchong Volcano-Geothermal Area (TVGA), western Yunnan Province of China, a 2-D crustal P velocity structure is obtained by use of finite-difference inversion and forward travel-time fitting method. The crustal model shows that a low-velocity anomaly zone exists in the upper crust, which is related to geothermal activity. Two faults, the Longling–Ruili Fault and Tengchong Fault, on the profile extend from surface to the lower crust and the Tengchong Fault likely penetrates the Moho. Moreover, based on teleseismic receiver functions on a temporary seismic network, S-wave velocity structures beneath the geothermal field show low S-wave velocity in the upper crust. From results of geophysical survey, the crust of TVGA is characterized by low P-wave and S-wave velocities, low resistivity, high heat-flow value and low Q. The upper mantle P-wave velocity is also low. This suggests presence of magma in the crust derived from the upper mantle. The low-velocity anomaly in upper crust may be related to the magma differentiation. The Tengchong volcanic area is located on the northeast edge of the Indian–Eurasian plate collision zone, away from the eastern boundary of the Indian plate by about 450 km. Based on the results of this paper and related studies, the Tengchong volcanoes can be classified as plate boundary volcanoes.

A Burial of a Viking Woman at Adwick-le-Street, South Yorkshire

In January 2001, an archaeological watching brief was carried out during the construction of a sewer pipeline at Adwick-le-Street near Doncaster in South Yorkshire. During excavation of a Romano-British trackway ditch, a plough-truncated grave was identified which produced fragmentary skeletal remains and an assemblage of copper-alloy and iron grave goods typical of a female Scandinavian burial of the Viking Period. The grave goods included a plough-damaged copper-alloy bowl, a non-matching pair of oval 'tortoise' brooches and fragments of an iron knife and a key or latch-lifter. Other objects might previously have been removed by ploughing. The oval brooches are typologically the earliest of the four pairs to have been recovered in England from a grave and the first to be excavated under archaeological conditions. The design and condition of the brooches suggest a date for the burial at the end of the 9th century. Isotope analysis of teeth from the skeleton indicates an origin for the woman in either Norway or possibly north-eastern Scotland. Investigation of the grave goods has provided information on manufacturing techniques and costume. No evidence was recovered to suggest why the woman was buried in this location, although a previous discovery of Roman or post-Roman inhumations and cremations nearby and the results of geophysical survey suggest that the excavated grave might form part of a more widely dispersed group of burials.

Asymmetric accretion along the slow‐spreading Mariana Ridge

We report the results of several surface geophysical surveys of the central part of the Mariana Basin, western Pacific. Analysis of bathymetric and magnetic data along three distinct spreading segments indicates highly asymmetric spreading processes, the half‐spreading rate being two to three times more important on the western side of the basin than on its eastern side. Such an asymmetry is as strong at the centers of segments as at their ends, and does not systematically correlate with an asymmetric shape of the rift valley. A half‐graben shape of the rift valley is observed only at segment ends. At segments centers, a symmetric graben shape characterizes the valley. The asymmetric shape of the valley at segment ends probably reflects the localization of the tectonic strain due to changes in lithospheric rheology and thickness. Asymmetric spreading is likely accomplished through a different amount of deformation and magma emplacement on both sides of the spreading axis. It may result from the combined effects of (1) asymmetric rheologic, melting and stress conditions imposed by the influence of the pre‐existing volcanic arc and its melt sources on the eastern side of the basin, (2) the northwestward movement of the Philippine Sea Plate while the almost vertical Pacific slab in the Mariana subduction zone resists to this motion, (3) a roll‐back component at the Mariana subduction zone.

Archaeological geophysics: 3D imaging studies at Muweilah, United Arab Emirates (UAE)

The sand covered Muweilah archaeological site in the United Arab Emirates (UAE) is a unique Iron Age site, and subject to intensive excavation. However, this time consuming process would require up to 20 years to complete. This paper presents preliminary results of geophysical surveys with the ultimate objective of characterising the site far more quickly.Ground penetrating radar (GPR) was trialed as a primary imaging tool with a very shallow time domain EM (MetalMapper) system in a supporting role. Dense 3D GPR datasets were migrated at 10 cm intervals to produce horizontal (plan view) slices which are conceptually similar to the excavation methodology used by archaeologists. The objective here was to delineate extensive linear and planar features. In addition, isolated scatterers were classified. Finally, MetalMapper images were used to discriminate between metallic and non metallic scatterers.The highly resistive sand cover provided GPR depth penetration of up to 5 m. GPR successfully mapped floor levels, walls and isolated anthropogenic activity, although in some cases crumbling walls were difficult to track. From this study two possible courtyard areas were recognised. The MetalMapper was less successful due to the limited depth penetration of 50 cm. Despite this, the system was still useful in detecting modern day ferruginous waste and bronze artefacts.The results (subject to ongoing ground-truthing) indicated that GPR was optimal for sites like Muweilah, which are buried under a few metres of sand. The 3D survey methodology proved essential to achieve line to line correlation for tracking walls. Although MetalMapper surveys were not as useful as hoped, they certainly indicated the value of including other geophysical data to constrain interpretation of complex GPR features. Practically, a significant improvement in data quality accrued when survey areas were flattened and de-vegetated.

Multidimensional prospecting in North American Great Plains village sites

AbstractGeophysical survey results are described for four prehistoric and historic fortified earthlodge settlements located in the Middle Missouri River basin of North and South Dakota, USA. One impetus for this work is the upcoming bicentennial of the Lewis and Clark expedition of 1804–1806 that used the Missouri as its route of travel. Celebrated as an event that helped to open the American West to Euroamerican settlement, tourism at archaeological parks is expected to markedly increase. Multidimensional geophysical surveys were used to pin‐point cultural anomalies for archaeological excavation and interpretation, but more importantly, the wide‐area mapping of the subsurface at these villages allowed visualization of their structure and organization, yielding many new insights. At Menoken Village (AD 1240) previously unknown houses, oval in form, were revealed magnetically owing to their intense burning, as was an intravillage trail system seen in resistivity data. At Whistling Elk Village (AD 1300) the first glimpse of the nature of this deeply buried settlement was achieved by resistivity and conductivity surveys, with magnetic indications that half of the houses had been burned. The geophysical evidence also hints at a second village, much more compact, that may lie within the primary settlement, supporting an attack theory established by limited excavation evidence. At Huff Village (AD 1450) the magnetometry survey revealed the presence of vast numbers of previously unsuspected food storage pits outside of the numerous dwellings that lie within this settlement. At Mitu'tahakto's (1822–1861), an early historic Mandan/Arikara settlement, resistivity and GPR surveys discovered the presence of new and overlapping houses, and magnetometry indicated large differences in the number of iron artefacts between households, pointing to possible variations in access or status. Copyright © 2003 John Wiley &amp; Sons, Ltd.

インドネシア，フローレス島ゴウ地域の地熱資源に関する 地質学・地球物理学・地球化学探査の総合結果

インドネシア，フローレス島ゴウ地域の地熱資源に関する 地質学・地球物理学・地球化学探査の総合結果

Alluvium and geophysical prospection

AbstractThe use of fluxgate gradiometry to investigate archaeological features under &gt;1 m of alluvium is a known problem. However, the frequent opinion that gradiometry has no role in the alluvial environment is incorrect. It is more accurate to say that the results of geophysical surveys are highly variable, as it is often overlooked that the survey results provide other information, most notably of a palaeoenvironmental nature. Four brief case studies are used to illustrate this point. These examples are drawn from geophysical surveys in the valleys of the River Trent, River Tame and River Great Ouse in the English Midlands. Copyright © 2001 John Wiley &amp; Sons, Ltd.

Groundwater resource assessments

SUMMARY Groundwater is a key component of water supply worldwide. In many areas, surface waters are inadequate or too polluted for effective utilization; while in other parts of the world groundwater is virtually the only source of water. Unfortunately groundwater is a fragile, finite, and often non-renewable resource. Overproduction and contamination threaten the water resource itself, and water supply conflicts threaten the peace and stability of neighbouring nations. Finding new, optimizing existing, and sustaining groundwater resources are extremely important components of water supply strategy. Rational application of geoscience principles and technology is a necessity for groundwater resource assessments, e.g. location of new water well drilling sites, optimizing and sustaining production from existing well fields, and detecting and mapping groundwater contamination. Geophysical surveys contribute to all aspects of the requirements for groundwater resource assessment. Importantly, geophysics provides remote, noninvasive information about subsurface geology, hydrogeology, and groundwater contamination. The results of geophysical surveys provide direct input to groundwater modelling and resource management.

The Ave Valley, northern Portugal: an archaeological survey of Iron Age and Roman settlement

The article presents the results of the HRB-funded survey of a sample of the Ave valley undertaken between 1994 and 1998. Introductory sections describe the geographical background and summarise the approaches followed. The field-walking results are then presented with especial emphasis on the ceramics. The field-walking evidence is used to identify a series of newly discovered sites which are assessed. The results of geophysical surveys of several of these sites are also presented. Information about the settlement patterns is presented based on a GIS analysis of both previously known sites and the results of the field-walking. Patterns in the changing distribution of settlement are discussed in relation to local social dynamics and the Roman annexation and exploitation of the region. The article is supported by databases which present the results of the field-walking and ceramic analyses. The article is jointly authored by: Martin Millett, Francisco Queiroga (Universidade Fernando Pessao, Porto), Kris Strutt, Jeremy Taylor and Steven Willis. The nature of a field-walking survey which produces a sequence of related databases (for field and finds) attached to a sequence of maps is particularly appropriate for electronic publication. Attempting such a publication in electronic form seems a worthwhile project in itself aside from the importance of the results.