Badania magnetyczne krateru Lonar

Lonar crater in India, centered at 19.97°N and 76.50°E is relatively young (few tens of thousands years) and, thus, well preserved meteorite impact structure. This 1.88-km-diameter simple structure has been formed into the 66 Ma old Deccan traps. As the target of Lonar is magnetically homogeneous, it is a perfect site to study the effect of relatively small impact event into the magnetic properties of rocks, and the magnetic field. In October 2017, has been performed ground magnetic mapping of Lonar with help of two proton precession magnetometers. The mapping was done in a squared area of about 36 km2 (6´6 km) including the crater depression, rims, and surrounding terrain. Magnetic map (not corrected for latitude) reveals a circular negative anomaly more than 1000 nT in amplitude, which corresponds to the crater depression. The negative anomaly is surrounded by semicircular feature of up to 500 nT positive anomalies that correlate with present rim of the crater. The total diameter of the Lonar magnetic anomalies is about 2.25 km, which is just 20% more compared to the crater rim-to-rim diameter.