Like most of us, Earth’s magnetic field isn’t perfect. Local variations in the field are known as magnetic anomalies, and they can be caused by differences in the compositional, structural, and thermal attributes of Earth’s crust. These anomalies can help scientists discern different types of rocks, folds, faults, and other structural features, as well as volcanism beneath obscuring materials like soil, glaciers, and water. Thus, magnetic anomalies are especially important for studying the crust in Antarctica, where thick ice sheets preclude traditional geologic mapping.
Now Golynsky et al. have greatly expanded scientists’ ability to scrutinize the southernmost continent’s geology by producing an updated version of the Antarctic Digital Magnetic Anomaly Project (ADMAP), the first comprehensive digital magnetic anomaly map of the region south of 60°S. The second-generation ADMAP-2 includes more than 3.5 million line-kilometers of marine and aeromagnetic survey results that more than double the near-surface data incorporated in the original 2001 map. These new data significantly improve anomaly resolution and help infill the coverage of Wilkes Land, Dronning Maud Land, the Transantarctic Mountains, continent-ocean margins, and other regions of geologic interest.
With its unprecedented level of detail, ADMAP-2 offers the most comprehensive view, to date, of the magnetic field over the southern continent and its encircling oceans. By integrating decades’ worth of data into a single resource, the authors have created a potent new tool to help geologists and geophysicists probe the planet’s minimally understood crust. It will inevitably kindle new investigations of the southern continent’s structure and tectonic evolution that will generate fresh insights into the events that have shaped Antarctica through multiple supercontinent cycles. (Geophysical Research Letters, https://doi.org/10.1029/2018GL078153, 2018)
—Terri Cook, Freelance Writer