Abstrakt
The impact structures are evidenced byeither large shatter cones and/or planardeformation features. We discovered anadditional new magnetic feature thatsupports formation by impact processes.Rock fragments from the impactites wereonce magnetized by a geomagnetic field.Paleointensity method on the rocks thatwere exposed to the shockwave byimpact, reveal more than an order ofmagnitude lower geomagnetic fieldintensity.
There is no known terrestrialrock demagnetization process capable ofachieving such demagnetization while therocks are exposed to a geomagnetic fieldduring the impact. In addition, themagnetic orientations after the impact arescattered in multiple orientations.
Weshow that the shock wave may have putthe magnetic grains into asuperparamagnetic-like state and left theindividual magnetized grains in randomorientations. Our data not only suggestthat an impact could have causedreduction of magnetic paleointensity butalso inspire a new direction of effort tostudy impact sites, using paleointensityas an approach, to answer new questionsabout physics of magnetic environmentduring the shock waves' caused byhypervelocity impacts.