Jeffrey Phillips (Former Employee)
Science and Products
Filter Total Items: 80
Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA
High-resolution airborne magnetic and gravity gradiometry data provide the geophysical framework for evaluating the exploration potential of hidden iron oxide deposits in Mesoproterozoic basement rocks of southeast Missouri. The data are used to calculate mineral prospectivity for iron oxide-apatite (IOA) ± rare earth element (REE) and iron oxide-copper-gold (IOCG) deposits. Results...
Authors
Anne E. McCafferty, Jeffrey Phillips, Rhonda L. Driscoll
Developing integrated methods to address complex resource and environmental issues Developing integrated methods to address complex resource and environmental issues
Introduction This circular provides an overview of selected activities that were conducted within the U.S. Geological Survey (USGS) Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing expertise. The project was supported by the...
Sharpening the boundaries - 3D terracing applied to physical property inversions Sharpening the boundaries - 3D terracing applied to physical property inversions
Physical property inversions typically result in smooth property distributions, without the sharp boundaries expected of true geologic sources. Here we explore the use of 3D terracing as a way to force the inverted physical properties to have sharp boundaries. Terracing during inversion is preferable to post-inversion terracing because it results in a better fit to the observed data.
Authors
Jeffrey Phillips, Robert W. Simpson
11.12 – Tools and techniques: gravitational method 11.12 – Tools and techniques: gravitational method
The gravitational method is used to investigate density variations within the subsurface at depths of several meters to tens of meters, as in depth-to-bedrock investigations, or at depths of several kilometers, as in sedimentary basin thickness investigations. This chapter covers fundamental relations, densities of Earth materials, instruments, field procedures, data reduction, filtering...
Authors
Jeffrey Phillips
A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation
The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR). In late September 2010, the U.S. Geological Survey (USGS)...
Authors
Jeffrey D. Phillips, Bethany L. Burton, Erika Curry-Elrod, Sigmund Drellack
Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography
A physical property inversion approach based on the use of 3D (or 2D) Fourier transforms to calculate the potential-field within a 3D (or 2D) volume from a known physical property distribution within the volume is described. Topographic surfaces and observations at arbitrary locations are easily accommodated. The limitations of the approach and applications to real data are considered.
Authors
Jeffrey Phillips
Science and Products
Filter Total Items: 80
Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA
High-resolution airborne magnetic and gravity gradiometry data provide the geophysical framework for evaluating the exploration potential of hidden iron oxide deposits in Mesoproterozoic basement rocks of southeast Missouri. The data are used to calculate mineral prospectivity for iron oxide-apatite (IOA) ± rare earth element (REE) and iron oxide-copper-gold (IOCG) deposits. Results...
Authors
Anne E. McCafferty, Jeffrey Phillips, Rhonda L. Driscoll
Developing integrated methods to address complex resource and environmental issues Developing integrated methods to address complex resource and environmental issues
Introduction This circular provides an overview of selected activities that were conducted within the U.S. Geological Survey (USGS) Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing expertise. The project was supported by the...
Sharpening the boundaries - 3D terracing applied to physical property inversions Sharpening the boundaries - 3D terracing applied to physical property inversions
Physical property inversions typically result in smooth property distributions, without the sharp boundaries expected of true geologic sources. Here we explore the use of 3D terracing as a way to force the inverted physical properties to have sharp boundaries. Terracing during inversion is preferable to post-inversion terracing because it results in a better fit to the observed data.
Authors
Jeffrey Phillips, Robert W. Simpson
11.12 – Tools and techniques: gravitational method 11.12 – Tools and techniques: gravitational method
The gravitational method is used to investigate density variations within the subsurface at depths of several meters to tens of meters, as in depth-to-bedrock investigations, or at depths of several kilometers, as in sedimentary basin thickness investigations. This chapter covers fundamental relations, densities of Earth materials, instruments, field procedures, data reduction, filtering...
Authors
Jeffrey Phillips
A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation A ground-based magnetic survey of Frenchman Flat, Nevada National Security Site and Nevada Test and Training Range, Nevada: data release and preliminary interpretation
The Nevada National Security Site (NNSS, formerly the Nevada Test Site) is located in southern Nevada approximately 105 kilometers (km) (65 miles) northwest of Las Vegas. Frenchman Flat is a sedimentary basin located on the eastern edge of NNSS and extending eastward into the adjacent Nevada Test and Training Range (NTTR). In late September 2010, the U.S. Geological Survey (USGS)...
Authors
Jeffrey D. Phillips, Bethany L. Burton, Erika Curry-Elrod, Sigmund Drellack
Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography Using vertical Fourier transforms to invert potential-field data to magnetization or density models in the presence of topography
A physical property inversion approach based on the use of 3D (or 2D) Fourier transforms to calculate the potential-field within a 3D (or 2D) volume from a known physical property distribution within the volume is described. Topographic surfaces and observations at arbitrary locations are easily accommodated. The limitations of the approach and applications to real data are considered.
Authors
Jeffrey Phillips
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government