Land Gravity Surveys
Magee Geophysical Services LLC conducts relative gravity surveys using Scintrex CG-5 (0.001 mGal resolution) and Lacoste and Rhomberg Model-G (0.01 mGal resolution) gravity meters. These instruments record variations in Earth’s gravitational field at ground level, which are used to detect density contrasts within the Earth. We use geodetic-grade GPS (real-time and post-processed) to achieve centimeter positioning accuracy for all gravity measurements.
Some applications include:
Geophysical Prospecting
We design, acquire, process, and interpret gravity data at the regional-, prospect-, and target-scale. The resulting reduced and filtered data can be used to infer near-surface structure, perform pseudo-geologic mapping, estimate basin depth, and aid in deposit detection/delineation.
Gravity Networks/Geoid Definition
Gravity measurements are fundamental for determining the figure of the Earth and are an important element in establishing accurate vertical control for today’s positioning systems. Our experience in planning, execution, processing, and QA/QC for both absolute and relative networks yields high-quality datasets with sufficient resolution to map regional geoid undulations, provide reliable gravity datums, determine near-surface vertical gravity gradients, and support regional isostatic investigations. For more info on our recent work with gravity networks, see About Us.
Geothermal Exploration and Groundwater Investigations
We can provide the data necessary to aid in the estimation of the size, shape, and depth of basins; the interpretation of controlling faults or other subsurface structures; and 2D or 3D modeling, which can help identify aquifer/aquitard horizons.
Reservoir Monitoring
Our use of survey-grade GPS, coupled with microgravity instruments (0.001 mGal), enables data collection with sensitivities acceptable for time-lapse gravity studies, a technique used in reservoir monitoring. Contact us for more information and learn how we can help you with your next project.
Ground Magnetic Surveys
We perform high-resolution (0.001 nT) ground magnetic surveys using Geometrics G-858 Cesium vapor magnetometers, which record variations in the Total Magnetic Intensity (TMI) of Earth’s geomagnetic field. Distortions of the field (both in strength and direction) caused by magnetic bodies or objects in the crust make the magnetic method a useful tool in near-surface investigations.
Our ground-based systems are designed to reduce both environmental and methodological noise, and the continuous operation of a base magnetometer allows correction of diurnal variations and monitoring for magnetic storms or micropulsations during a survey.
Our roving magnetometers are integrated with differentially corrected GPS (WAAS) for real-time navigation and positioning, and provide continuous mode surveying with sampling rates up to 10 Hz.
Ground magnetic methods are useful in geothermal, mineral, and oil/gas exploration and can be successful in direct detection/delineation of controlling structures, favorable lithotypes, mineral deposits, or mineralizing environments. Additionally, ground magnetic data (either stand-alone or combined with gravity data) is a cost-efficient way to impose important geological constraints and/or to inform other geophysical methods (e.g., seismic, CSAMT, IP, EM) during modeling.
Contact us for more information and learn how we can help you with your next project.
Consulting Services
We provide consulting services, including data merges, reprocessing, filtering, and creation of interpretive products for many geophysical methods. Additionally, we provide survey design, QC/QA services, and can provide knowledgeable personnel to train local staff on proper survey procedures.
Contact us for more information and learn how we can help you with your next project.
Other Services
Data Processing
Our data processing is completed daily, in the field, following data acquisition to provide high-quality results in a timely manner.
Gravity data are processed in Geosoft Oasis Montaj and reduced to the Complete Bouguer Anomaly (CBA) using standard procedures. Our use of survey-grade GPS, local slope measurements, 10m- and 30m-USGS digital elevation models (DEMs), and/or merged proprietary elevation data enables accurate terrain correction calculations in the local, intermediate, and far-field zones.
Gravity data are presented as color-contoured images of gridded CBA data, and we also offer the standard suite of gridded derivative products, including regional/residual separation, vertical derivative, horizontal gradient, and analytic signal.
Raw magnetic data are filtered and diurnally corrected using Geometrics Magmap2000 software, then imported into Geosoft Oasis Montaj for further graphical removal of environmental noise. Data are presented as color-contoured images of the gridded Total Magnetic Intensity, and reduced-to-pole transformations can be produced as necessary.
Exploration Grids and GPS Services
We can efficiently and accurately establish exploration grids for other geophysical and geochemical surveys (e.g., soil, seismic, electromagnetic, and magnetotelluric surveys). Other GPS services include centimeter-accuracy drillhole location surveys and the calculation of local site transformations to known datums.
Worldwide Experience
With experience in over 40 countries worldwide, we have the resources and crew to tackle any job, regardless of its geographic location.
- Canada
- USA
- Mexico
- Dominican Republic
- Belize
- Jamaica
- Guatemala
- Costa Rica
- St. Lucia
- Sudan
- Kenya
- Tanzania
- Zimbabwe
- Zambia
- Somalia
- Morocco
- Congo
- Malta
- Oman
- United Arab Emirates
- Pakistan
- Kurdistan Region of Iraq
- Thailand
- China
- Papua New Guinea
- Indonesia
- Australia
- Norway
- United Kingdom
- France
- Germany
- Spain
- Romania
- Serbia
- Kingdom of Saudi Arabia
- Cypress
- Colombia