scholarly journals A Reconnaissance Geophysical Survey of the Kawartha Lakes and Lake Simcoe, Ontario

2007 ◽  
Vol 47 (3) ◽  
pp. 313-323 ◽  
Author(s):  
Brian J. Todd ◽  
C. F. Michael Lewis
Keyword(s):  
Geophysical Survey ◽  
Paleozoic Rock ◽  
Lower Unit ◽  
Western Lake ◽  
Strong Reflection ◽  
Geophysical Surveys ◽  
Glacier Ice ◽  
Reflection Configuration ◽  
Lake Simcoe ◽  
Tectonic Origin

ABSTRACT A marine geophysical survey program has been conducted in lakes of southern Ontario. The survey was designed to detect neotectonic features, if they exist, and to evaluate their geological importance. High-resolution single- and multichannel seismic reflection profiling were used to delineate late- and post-glacial sedimentary strata and structures, as well as the sediment/bedrock interface, in the Kawartha Lakes and Lake Simcoe. Results show that two seismostratigraphic sequences are common within the unconsolidated overburden. The lower unit exhibits a parallel reflection configuration having strong reflection amplitudes, whereas the upper unit is acoustically transparent and overlies the lower unit conformably in some places and unconformably in others. Both units vary in thickness within lakes and from lake to lake. Typical subbottom profiles of Precambrian rock surfaces are rolling; those of Paleozoic rock surfaces are smooth. At one location in Lower Buckhorn Lake, tilted rock surfaces may be faulted but disturbance of overlying glacioge-nic sediments was not observed. In western Lake Simcoe and Kempenfelt Bay, slumping into graben-like features was observed. Also in Lake Simcoe, a diapiric feature was documented. It is speculated that these disturbances most likely result from glacier ice block melting and fluid migration. A tectonic origin, however, cannot be discounted at this stage of investigation. Additional systematic marine geophysical surveys are required in the future to map features in detail to determine whether they are of neotectonic or glaciotectonic origin.

High-Resolution Magnetic And Seismic Imaging Of Basement Faults In Western Lake Ontario And Lake Simcoe, Canada

2002 ◽  
Author(s):  
Joe I. Boyce ◽  
Matthew R. Pozza ◽  
William A. Morris ◽  
Nicholas Eyles ◽  
Mike Doughty
Keyword(s):  
High Resolution ◽  
Seismic Imaging ◽  
Lake Ontario ◽  
Basement Faults ◽  
Western Lake ◽  
Lake Simcoe

Petroleum geological activities onshore West Greenland in 1997

1998 ◽  
pp. 10-17
Author(s):  
Flemming G. Christiansen ◽  
Anders Boesen ◽  
Jørgen A. Bojesen-Koefoed ◽  
Finn Dalhoff ◽  
Gregers Dam ◽  
...  
Keyword(s):  
Field Work ◽  
Early Summer ◽  
Summer Season ◽  
Project Manager ◽  
Geophysical Survey ◽  
Original Series ◽  
West Greenland ◽  
Low Level ◽  
The Third ◽  
Geophysical Surveys

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Christiansen, F. G., Boesen, A., Bojesen-Koefoed, J. A., Dalhoff, F., Dam, G., Neuhoff, P. S., Pedersen, A. K., Pedersen, G. K., Stannius, L. S., & Zinck-Jørgensen, K. (1998). Petroleum geological activities onshore West Greenland in 1997. Geology of Greenland Survey Bulletin, 180, 10-17. https://doi.org/10.34194/ggub.v180.5079 _______________ The 1997 summer season saw continued petroleum geological activities in the Disko–Nuussuaq–Svartenhuk Halvø area, onshore West Greenland. These activities mainly took the form of a geological field project led by the Geological Survey of Denmark and Greenland (GEUS), whereas the continued exploration by grønArctic Energy Inc. (grønArctic) in the third year of their licence was kept at a very low level without field work, geophysical surveys or drilling. Furthermore an airborne geophysical survey, Aeromag 1997, covering a large part of the Disko Bugt area, was carried out in the early summer of 1997 with GEUS as project manager (Stemp 1997; Stemp & Thorning 1998, this volume).

Combining traditional and geophysical soil investigation for phytoremediation planning in a hydrocarbon polluted area

2021 ◽  
Author(s):  
Chiara Ferré ◽  
Enrico Casati ◽  
Gabriele Cerutti ◽  
Rodolfo Gentili ◽  
Alberto Francioli ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Arable Land ◽  
Chemical Properties ◽  
Soil Survey ◽  
Geophysical Survey ◽  
Soil Parameters ◽  
Heavy Hydrocarbons ◽  
Soil Map ◽  
Geostatistical Approach ◽  
Geophysical Surveys

<p>The spatial variability of hydrocarbon content and the physical and chemical properties of the soil were assessed by combining traditional soil sampling and proximal geophysical survey with the aim of planning a pilot phytoremediation experiment in an agricultural area west of Milan (Lombardy, Italy).</p><p>The area, an irrigated arable land of about 1 ha, was affected by a refined oil spillage from an underground pipeline in 2015. Contamination surveys were carried out with a continuous core drilling technique using an hydraulic probe (131 cm diameter core). Heavy (C>12) and light (C<12) alkanes and aromatic compounds (benzene, ethylbenzene, styrene, toluene and xilenes) were measured up to three meters depth. Results showed a predominance of heavy hydrocarbons (C>12) with respect to light hydrocarbons (C<12) and aromatic compounds. A map of heavy hydrocarbons soil concentration was obtained using geostatistical techniques.</p><p>In 2019 it was decided to carry out a phytoremediation intervention to reclaim the first meter of contaminated soil where heavy hydrocarbons content ranges from 500 to 5000 mg/kg. The first step of the intervention consists in cultivating a wide variety of vegetal species in experimental plots with different pollution to verify their effectiveness for remediation in the specific environmental condition of that area. For the reclamation of deeper more contaminated layers, enhanced bioremediation have been planned to be used.</p><p>Soil properties, which are crucial for planning phytoremediation activities, were investigated using traditional methods and geophysical surveys. Traditional soil survey was performed describing the 23 drilling cores used to monitor pollutants and opening five profiles; the samples were collected from genetic soil horizons and analysed for organic carbon and the main nutrient (nitrogen, phosphorus and potassium) content, total carbonates, texture and pH in water. The distribution of Eutric Luvisols and Cambisols, developed mainly on sandy or sandy skeletal substrate, was represented in a soil map. A proximal geophysical survey was carried out using an electromagnetic induction (EMI) sensor (GSSI Profiler EMP-400) by acquiring multiple frequencies; soil detailed conductivity maps for each frequency (15000, 9000 and 2000 kHz) were obtained. No significant relationships were found between soil electrical conductivity and hydrocarbon concentration, whereas there are relationships with the main soil characteristics: this allowed detailed maps of soil parameters to be obtained.</p><p>On the base of both the soil spatial characterization (traditional soil map and detailed soil property maps with geophysical approach) and the contaminant distribution (hydrocarbon map distribution using geostatistical approach), homogeneous areas were identified in which to set up experimental phytoremediation plots to test the most suitable species for reclamation, chosen among the most widespread crops in the region and considering their suitability for biomass and bio-oil production.</p>

GEOPHYSICAL SURVEY OF THE ARKANSAS BAUXITE REGION

Geophysics ◽  
1944 ◽  
Vol 9 (3) ◽  
pp. 324-366 ◽  
Author(s):  
Mark C. Malamphy ◽  
James L. Vallely
Keyword(s):  
Hot Spring ◽  
Geophysical Survey ◽  
Geophysical Data ◽  
Magnetic Survey ◽  
Large Area ◽  
Clark County ◽  
Ore Bodies ◽  
Geophysical Surveys ◽  
Bauxite Ore ◽  
Geophysical Anomalies

Magnetic and gravimetric surveys were conducted over an area of approximately 1400 square miles in the bauxite district of central Arkansas. The primary purpose of these surveys was to discover any possible buried and hitherto unknown syenite masses favorable for the occurrence of bauxite and to determine the approximate position of the buried flanks of the known syenite masses which might offer conditions favorable for the discovery of new ore bodies. These surveys indicated that the various syenite outcrops are domes or bosses on a large batholith and that other similar domes occur on the batholith but do not outcrop. Drilling on the local geophysical anomalies proved the presence of 10 buried domes, but only 2 were found to project above the upper surface of the Midway clays, a requisite of conditions favorable for the occurrence of bauxite ore bodies. The geophysical data indicated the approximate configuration of the buried flanks of the known syenite outcrops, and the portions of these flanks that project above the Midway have now been outlined more accurately by drilling. The geophysical surveys have produced evidence permitting the elimination of a large area as unfavorable for the occurrence of bauxite. Magnetic surveys extending along the Midway‐Wilcox contact from Gurdon in Clark County on the southwest to Searcy in White County on the northeast have proved the improbability of the existence of other syenite masses similar to those found in Pulaski and Saline Counties. A detailed magnetic survey of the Magnet Cove area in Hot Spring County has proved that the syenite mass exposed in that locality is an isolated intrusion and entirely unrelated to those of Pulaski and Saline Counties. This syenite mass does not occur under conditions believed to be favorable for the occurrence of bauxite.

scholarly journals Integrated geophysical surveys to assess the structural conditions of a karstic cave of archaeological importance

2005 ◽  
Vol 5 (1) ◽  
pp. 17-22 ◽  
Author(s):  
G. Leucci ◽  
L. De Giorgi
Keyword(s):  
Carbonate Rock ◽  
Data Interpretation ◽  
Geophysical Survey ◽  
Resistivity Tomography ◽  
Scattered Energy ◽  
Geophysical Surveys ◽  
The Stability ◽  
Geotechnical Tests ◽  
Ground Penetrating ◽  
Integrated Geophysical Survey

Abstract. An integrated geophysical survey using both the electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) methods was undertaken over a cave of great archaeological interest in southern Italy. The survey was performed to assess the stability of the carbonate rock roof of the cave. A geophysical survey was preferred to boreholes and geotechnical tests, in order to avoid the risk of mass movements. The interpretation of integrated data from ERT and GPR resulted in an evaluation of some of the electromagnetic (EM) characteristics (such as the EM wave velocity) and the detection of discontinuities (fractures) in the carbonate rock. It is well known that rock fractures constitute a serious problem in cave maintenance, and progressive cracking within the bed rock is considered to be one of the main causes of collapse. An analysis of the back-scattered energy was also required for the GPR data interpretation. Cracks within the bedrock were detected to a depth of about 2 m by using GPR, which allowed for the identification of the loosened zone around the cave.

scholarly journals Geophysical survey at late roman Mediana

Starinar ◽  
2011 ◽  
pp. 275-284
Author(s):  
Gordana Milosevic ◽  
Daniel Peters ◽  
Holger Wendling
Keyword(s):  
Geophysical Survey ◽  
Archaeological Remains ◽  
Geophysical Surveys ◽  
The University ◽  
The Town ◽  
Non Destructive ◽  
Destructive Methods ◽  
Late Roman

This article discusses the results of geophysical surveys conducted at Mediana, near the town Nis (Serbia) in April 2010. The research was realized in cooperation with the Romano-Germanic Commission of the German Archaeological Institute, the Archaeological Institute and the University of Belgrade. Mediana geomagnetic prospecting sites, as a form of non-destructive methods of investigation, provided many new details about the architectural and archaeological remains, particularly in the eastern part of the site.

Geophysical Survey and Rural Settlement Architecture on the Lower Danube at the Transition to Late Antiquity

2007 ◽  
Author(s):  
M. J. BOYD
Keyword(s):  
Late Antiquity ◽  
Settlement Patterns ◽  
Research Programme ◽  
Rural Settlement ◽  
Geophysical Survey ◽  
Total Density ◽  
Large Area ◽  
Density Distributions ◽  
Geophysical Surveys ◽  
Local Patterns

One of the key aims of the ‘Transition to Late Antiquity’ research programme has been to collect a systematic data sample in order to examine local patterns and disparities at a regional level. In this project, an understanding of inter- and intra-settlement patterns of occupation is primarily acquired by calculating total density distributions of surface material, but for the examination of individual architectural units and the relationships between them, a geophysical survey has been used because of its particular ability to provide detailed information about subsurface features over a large area without excavation. This chapter describes the approach and methodology employed in the geophysical surveys carried out to assess rural settlement patterns in Bulgaria (lower Danube) as part of the ‘Transition to Late Antiquity’ research programme. Examples of particular surveys — which in general have proved remarkably successful — are used to illustrate the results.

The Paleocene Chance Member of the Fort Union Formation, northern Bighorn Basin, Montana and Wyoming: aperiodic cyclothems in a tectonically dominated lake basin

2016 ◽  
Vol 53 (4) ◽  
pp. 259-281
Author(s):  
Leo Hickey ◽  
Richard Yuretich
Keyword(s):  
Variable Thickness ◽  
Flood Plain ◽  
Union Formation ◽  
Lake Basin ◽  
Bighorn Basin ◽  
Time Intervals ◽  
Lower Unit ◽  
Fort Union Formation ◽  
Tectonic Origin

A 400 m-thick sequence characterized by prominent tabular sandstone beds and a significant amount of marl and limestone occurs in Paleocene strata of the northern part of the Bighorn Basin (Clarks Fork Basin) of Wyoming and Montana. These strata, currently designated as the Belfry Member of the Fort Union Formation, actually consist of two separate but related lithogenetic units. The lower unit, which includes the Belfry Member stratotype, shows a gradual upward increase in tabular sandstone and marl or limestone and is inferred to have been deposited on a drowning flood plain under paralacustrine conditions. The upper unit, here proposed as the Chance Member, is characterized by the presence of six asymmetrical, basin-wide cyclothems. Each cycle begins abruptly with a transgressive surface overlain by laterally extensive tabular sandstone, followed by a micrite-dominated interval that together represent the lacustrine phase of the cycle. These are succeeded by lenticular interbeds of mudstone and sandstone inferred to have been deposited as a prograding fluvio-deltaic and flood plain sequence. The cyclothems are of variable thickness, ranging from ∼30m in the lowest cycle to ∼10 m in the uppermost cycles. Detailed stratigraphic mapping and correlation with the paleomagnetic and vertebrate biostratigraphic framework for the Bighorn Basin places the entire Chance Member within a portion of one vertebrate zone, Ti4, of the middle Tiffanian Provincial Age (59.2 to 58.5 Ma). The variable thickness of the cycles points toward deposition during unequal time intervals and suggests a tectonic origin most likely related to episodic movement of faults bounding the Bighorn Basin.

scholarly journals A comparison of seismic and radar methods to establish the thickness and density of glacier snow cover

2013 ◽  
Vol 54 (64) ◽  
pp. 73-82 ◽  
Author(s):  
Adam D. Booth ◽  
Andrew Mercer ◽  
Roger Clark ◽  
Tavi Murray ◽  
Peter Jansson ◽  
...  
Keyword(s):  
Lower Layer ◽  
Effective Means ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Ground Truth ◽  
Snow Layer ◽  
Refraction Seismic ◽  
Geophysical Surveys ◽  
Glacier Ice ◽  
Snow Thickness

AbstractWe show that geophysical methods offer an effective means of quantifying snow thickness and density. Opportunistic (efficient but non-optimized) seismic refraction and ground-penetrating radar (GPR) surveys were performed on Storglaciären, Sweden, co-located with a snow pit that shows the snowpack to be 1.73 m thick, with density increasing from ∼120 to ∼500 kg m–3(with a +50 kg m–3anomaly between 0.73 and 0.83 m depth). Depths estimated for two detectable GPR reflectors, 0.76 ±0.02 and 1.71 ± 0.03 m, correlate extremely well with ground-truth observations. Refraction seismic predicts an interface at 1.90 ± 0.31 m depth, with a refraction velocity (3730 ± 190 ms–1) indicative of underlying glacier ice. For density estimates, several standard velocity-density relationships are trialled. In the best case, GPR delivers an excellent density estimate for the upper snow layer (observed = 321 ± 74 kg m–3, estimated = 319 ± 10 kgm–3) but overestimates the density of the lower layer by 20%. Refraction seismic delivers a bulk density of 404 ±22 kgm–3compared with a ground-truth average of 356 ± 22 kg m–3. We suggest that geophysical surveys are an effective complement to mass-balance measurements (particularly for controlling estimates of snow thickness between pits) but should always be validated against ground-truth observations.

High‐Resolution Magnetic and Seismic Imaging of Basement Faults in Western Lake Ontario and Lake Simcoe, Canada

2002 ◽  
Author(s):  
Joe I. Boyce ◽  
Matthew R. Pozza ◽  
William A. Morris ◽  
Nicholas Eyles ◽  
Mike Doughty
Keyword(s):  
High Resolution ◽  
Seismic Imaging ◽  
Lake Ontario ◽  
Basement Faults ◽  
Western Lake ◽  
Lake Simcoe
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