Global map of magnetic anomalies imprinted onto the seafloor of the Earth in form of characteristic magnetic stripes and other patterns. The magnetic anomalies are not only observable on the seafloor, but also provide insight into the subsurface structure and composition of the Earth’s crust. Anomalies trending parallel to the isochrons (lines of equal plate age) in the oceans reveal the temporal growth of oceanic plate and crust: seafloor spreading.
Ever so often the Earth’s magnetic field flips its polarity in an occurrence called a geomagnetic reversal. These reversals throughout Earth’s history are recorded in solidifying rocks, such as in the ones making up the growing oceanic crust at mid-oceanic ridges. The successive bands of ocean floor representing alternating magnetic polarity parallel with mid-ocean ridges was important evidence for seafloor spreading, the concept central to the acceptance of the early theory of plate tectonics.
The data plotted is from the global Earth Magnetic Anomaly Grid (EMAG2) and was compiled from satellite, ship and airborne magnetic measurements.
- Creator: Fabio Crameri
- This version: 05.12.2024
- License: Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
- Specific citation: This graphic by Fabio Crameri is available via the open-access s-ink.org repository.
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- Various other map projections included
- Dark and light background versions
- Transparent background
- Colour-vision deficiency friendly
- Readable in black&white
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