Nevada Magnetic and Gravity Maps and Data: A Website for the Distribution of Data

Magnetic anomalies are due to variations in the Earth's magnetic field caused
by the uneven distribution of magnetic minerals (primarily magnetite) in the
rocks that make up the upper part of the Earth's crust. The features and
patterns of the magnetic anomalies can be used to delineate details of
subsurface geology, including the locations of buried faults and
magnetite-bearing rocks and the depth to the base of sedimentary basins. This
information is valuable for mineral exploration, geologic mapping, and
environmental studies.

The Nevada magnetic map is constructed from grids that combine information (see
data processing details) collected in 82 separate magnetic surveys conducted
between 1947 and 2004. The data from these surveys are of varying quality. The
design and specifications (terrain clearance, sampling rates, line spacing, and
reduction procedures) varied from survey to survey depending on the purpose of
the project and the technology of that time.

[Summary provided by the USGS.]