Geochemical signals of the late Jurassic, marine Mjolnir impact

Of the only seven submarine impact craters that have been found globally, t he Mjolnir crater is one of the best preserved and retains crater and eject a. Geochemical studies (organic pyrolysis using the Rock Eval technique and XRF analysis for major, minor, and trace elements) of the Institute for Pe troleum Research (IKU) core 7430/10-U-01 that was taken from a drillhole lo cated similar to 30 km north-northeast of the crater rim show gradual estab lishment of anoxic sea floor conditions through the late Jurassic. These po orly ventilated water conditions were overturned due to the Mjolnir impact event. Waves and currents transported impact glass (which is now partly wea thered to smectite) into the depositional area where the drillhole is locat ed. The succeeding crater collapse transported impact material (e.g., shock ed quartz and Ir) from the crater rim and deeper levels to the core site. N ormal marine depositional conditions were established a short time after th e crater collapsed.