VUME Upper Mantle of the Earth

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Magnetic Maps for the Earth's Surface.





Magnetic anomaly maps provide insight into the subsurface structure and composition of the Earth's crust. Anomalies trending parallel to the isochrons (lines of equal age) in the oceans reveal the temporal evolution of oceanic crust. Magnetic maps are widely used in the geological sciences and in resource exploration. Furthermore, the global magnetic map is useful in science education to illustrate various aspects of Earth evolution such as plate tectonics and crustal interaction with the deep mantle. Distinct patterns and magnetic signatures can be attributed to the formation (seafloor spreading) and destruction (subduction zones) of oceanic crust, the formation of continental crust by accretion of various terranes to cratonic areas and large scale volcanism (both on continents and oceans).






EMAG2 is a significant update over our first global magnetic anomaly grid, EMAG3, which provided the base grid for the World Digital Magnetic Anomaly Map of the Commission of the World Geological Map.
As reflected in the name the resolution has been improved from 3 arc minute to 2 arc minute and the altitude has been reduced from 5 km to 4 km above geoid.
Additional grid and trackline data have been included, both over land and the oceans. Interpolation between sparse tracklines in the oceans was improved by directional gridding and extrapolation, based on an oceanic crustal age model .
The longest wavelengths (larger than 330 km) were replaced with the latest CHAMP lithospheric field model MF6.

EMAG2 figure 1

Figure: (click to enlarge)

EMAG2 looking north-west at Portugal/Spain from the Atlantic. Kursk (Russia) is seen as a strong anomaly in the background. The stripes on the left of the image are magnetic lineations due to sea-floor spreading. Plug-in files for NASA World Wind can be downloaded from GETECH .

Geomagnetic anomalies





EMAG2 is specified as a global 2-arc-minute resolution grid of the anomaly of the magnetic intensity at an altitude of 4 km above mean sea level.
It was compiled from satellite, marine, aeromagnetic and ground magnetic surveys (see our acknowledgment of data providers and collaborators). A version for visualization in NASA World Wind can be downloaded from GETECH .
See also the implementations for EMAG2 in Google Earth and EMAG2 in Google Maps.
EMAG2 is also available as a print map (on paper or to self-print from PDF) from the German Federal Institute for Geosciences and Natural Resources (BGR). To order/download the map please visit the BGR Geoshop.