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Magnetic and related derivative GeoTIFF grids and data for the United States and Canada

Metadata Updated: October 28, 2023

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, Miles, W., and Oneschuk, G., 2016, Magnetic anomaly map, Canada / Carte des anomalies magnetiques, Canada: Geological Survey of Canada Open File 7799, 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, [Also available at]

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources


Metadata Created Date August 30, 2023
Metadata Updated Date October 28, 2023

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date August 30, 2023
Metadata Updated Date October 28, 2023
Publisher U.S. Geological Survey
Identifier USGS:619a9a3ad34eb622f692f961
Data Last Modified 20230814
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 40db53fc-f83f-41fb-87a5-3c981e59d3b5
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -178.9453,24.2069,-52.6311,83.1029
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash e0e1027e48cf2760164331dda707bf7a31aa445f593524d80c3bc09c09264bb3
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -178.9453, 24.2069, -178.9453, 83.1029, -52.6311, 83.1029, -52.6311, 24.2069, -178.9453, 24.2069}

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