[Geophysical Data] Magnetic and related derivative GeoTIFF grids and data for the United States and Canada

Dates

Publication Date: 2023-08-14
Start Date: 1948-12-31
End Date: 2016-12-31

Citation

McCafferty, A.E., San Juan, C.A., Lawley, C.J.M., Graham, G.E., Gadd, M.G., Huston, D.L., Kelley, K.D., Paradis, S., Peter, J.M., and Czarnota, K., 2023, National-scale geophysical, geologic, and mineral resource data and grids for the United States, Canada, and Australia: Data in support of the tri-national Critical Minerals Mapping Initiative: U.S. Geological Survey data release, https://doi.org/10.5066/P970GDD5.

Summary

This directory includes GeoTIFF grids and shapefiles of magnetic data that cover the countries of the US and Canada. GeoTIFF grids of national-scale magnetic anomaly data for the conterminous United States (Ravat and others, 2009), Alaska (Division of Geological and Geophysical Surveys, 2016) and Canada (Miles and Oneschuk, 2016) were merged to create a composite residual magnetic anomaly grid of the United States and Canada. Several derivative products were calculated from the residual magnetic anomaly grid and are provided in this directory. Derivative grids include a reduced-to-pole (RTP) magnetic anomaly grid, the 1st vertical derivative of the RTP, the horizontal gradient magnitude pseudo-gravity calculated from the RTP grid, [...]

Summary

This directory includes GeoTIFF grids and shapefiles of magnetic data that cover the countries of the US and Canada. GeoTIFF grids of national-scale magnetic anomaly data for the conterminous United States (Ravat and others, 2009), Alaska (Division of Geological and Geophysical Surveys, 2016) and Canada (Miles and Oneschuk, 2016) were merged to create a composite residual magnetic anomaly grid of the United States and Canada. Several derivative products were calculated from the residual magnetic anomaly grid and are provided in this directory. Derivative grids include a reduced-to-pole (RTP) magnetic anomaly grid, the 1st vertical derivative of the RTP, the horizontal gradient magnitude pseudo-gravity calculated from the RTP grid, the long-wavelength RTP magnetic anomaly, and the horizontal gradient magnitude of the long wavelength pseudo gravity calculated from the long wavelength RTP. The directory also includes shapefiles of locations that trace the maxima of the horizontal gradient magnitude of the pseudo-gravity and of the maxima of the horizontal gradient magnitude of the long wavelength RTP transformed to pseudo-gravity. Otherwise known as “worms”, the points tracking the maxima mark the edges of shallow magnetic sources (in the case of the RTP) and deeper magnetic sources (calculated from the long-wavelength RTP grid). The shapefile of worms also includes attribute fields related to the steepness of the gradient and to the trend or strike of the gradient. These products were used in combination with other geophysical and geological data layers as input into a mineral prospectivity model for basin-hosted Pb-Zn mineralization. The reader is encouraged to read the metadata specific to each data layer for details related to the calculation and derivation of each magnetic anomaly GeoTIFF grid or shapefile.

References
Division of Geological and Geophysical Surveys, 2016, Alaska merged geophysical data grids: Alaska Division of Geological and Geophysical Surveys Digital Data Series 12, https://doi.org/10.14509/29555.

Miles, W., and Oneschuk, G., 2016, Magnetic anomaly map, Canada / Carte des anomalies magnetiques, Canada: Geological Survey of Canada Open File 7799, https://doi.org/10.4095/297337.

Ravat, D., Finn, C., Hill, P., Kucks, R., Phillips, J., Blakely, R., Bouligand, C., Sabaka, T., Elshayat, A., Aref, A., and Elawadi, E., 2009, A preliminary, full spectrum, magnetic anomaly grid of the United States with improved long wavelengths for studying continental dynamics: A website for distribution of data: U.S. Geological Survey Open-File Report 2009-12258, https://doi.org/10.3133/ofr20091258. [Also available at https://pubs.usgs.gov/of/2009/1258/.]

Contacts

Point of Contact :: Anne E McCafferty
Originator :: Anne E McCafferty
Metadata Contact :: Anne E McCafferty, GS GGGSC DM Team
Publisher :: U.S. Geological Survey
USGS Mission Area :: Energy and Minerals
USGS Program :: Mineral Resources Program
SDC Data Owner :: Geology, Geophysics, and Geochemistry Science Center
Distributor :: U.S. Geological Survey - ScienceBase

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GeophysicsMagAndRelatedDerivatives_USCanada.xml “FGDC metadata” Original FGDC Metadata	View	35.53 KB	application/fgdc+xml
GeophysicsMagRTP_DeepSources_USCanada.zip “GeoTIFF-Long-wavelength RTP-US and Canada”		29.19 MB	application/zip
GeophysicsMagRTP_HGM_DeepSources_USCanada.zip “GeoTIFF-Horz gradient magnitude of long wavelength psdgravity-US and Canada”		24.84 MB	application/zip
GeophysicsMagRTP_DeepSources_USCanada.jpg “Map-Long-wavelength magnetic anomaly-US and Canada”		3.01 MB	image/jpeg
GeophysicsMagRTP_DeepSources_Worms_USCanada.jpg “Map-Edges of deep magnetic sources-US and Canada”		1.99 MB	image/jpeg
GeophysicsMagRTP_HGM_DeepSources_USCanada.jpg “Map-Horz gradient magnitude of long wavelength psdgravity-US and Canada”		1.09 MB	image/jpeg
GeophysicsMagRTP_ShallowSources_Worms_USCanada.jpg “Map-Edges of shallow magnetic sources-US and Canada”		3.6 MB	image/jpeg
DeepMagSources_Worms_USCanada.zip “Shapefile-Edges of deep magnetic sources, US and Canada”		2.94 MB	application/zip
ShallowMagSources_Worms_USCanada.zip “Shapefile-Edges of shallow magnetic sources US Canada”		40.53 MB	application/zip
GeophysicsMag_USCanada.jpg “Map-Magnetic anomaly of US and Canada”		3.98 MB	image/jpeg
GeophysicsMag_USCanada.zip “GeoTiff-Magnetic anomaly of US and Canada”		127.3 MB	application/zip
GeophysicsMag_RTP.jpg “Map-RTP magnetic anomaly of US and Canada”		4.57 MB	image/jpeg
GeophysicsMag_RTP_USCanada.zip “GeoTiff-RTP magnetic anomaly of US and Canada”		128.43 MB	application/zip
GeophysicsMag_RTP_HGM_USCanada.zip “GeoTiff-HGM of pseudo-gravity US and Canada”		123.61 MB	application/zip
GeophysicsMag_RTP_VD_USCanada.zip “Map-1st vertical derivative magnetics-US and Canada”		129.34 MB	application/zip
GeophysicsMag_RTP_VD_USCanada..jpg “Map-1st vertical derivative magnetics-US and Canada”		4.44 MB	image/jpeg
GeophysicsMag_RTP_HGM_USCanada.jpg “Map-HGM of pseudogravity US and Canada”		4.55 MB	image/jpeg

Related External Resources

Type: Citation

Alaska merged geophysical data grids	https://doi.org/10.14509/29555
Magnetic anomaly map, Canada / Carte des anomalies magnetiques, Canada	https://doi.org/10.4095/297337
A preliminary, full spectrum, magnetic anomaly grid of the United States with improved long wavelengths for studying continental dynamics: A website for distribution of data	https://doi.org/10.3133/ofr20091258

Purpose

The purpose of this data release is to provide a composite magnetic anomaly dataset for the United States and Canada. This dataset was used in developing prospectivity models for basin-hosted Pb-Zn mineralization as part of the tri-national Critical Minerals Mapping Initiative, a collaboration between the national geological surveys of the United States (U.S. Geological Survey), Canada (Geological Survey of Canada) and Australia (Geoscience Australia).

[Geophysical Data] Magnetic and related derivative GeoTIFF grids and data for the United States and Canada

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