Ich bin nun wahrlich auch kein Experte für diese Dinge, aber ich tippe mal auf....
-->> POPIGAI (Nordsibirien)
Wikipedia sagt: The Popigai crater in Siberia, Russia is tied with Manicouagan Reservoir as the 4th largest impact crater on Earth. A large bolide impact created the 100-kilometer diameter crater about 35 million years ago during the late Eocene epoch. The Popigai impact crater was possibly simultaneous with the Chesapeake Bay and Toms Canyon impacts, but evidence varies. The impactor in this event has been identified as either an eight-kilometer diameter chondrite asteroid, or a five-kilometer diameter stony asteroid. The shock pressures from the impact instantaneously transformed graphite in the ground into diamonds within a 13.6 kilometer radius of ground zero. No exact count nor measure of caratage has been made available, but it is estimated that this one impact formed more diamonds than have been formed by the Earth's own processes. Popigai is the best example yet of the formation of a crater of this type. Three other craters are larger, but they are either buried (Chicxulub), strongly deformed (Sudbury), or deformed and severely eroded (Vredefort).
...und im Zshg mit Popigai wird halt auch "Lechatelierite" in der Literatur erwähnt...
Hätte auch Manicouagan (Canada) tippen können, aber das mag dann ein anderer tun und vielleicht mehr Glück haben!...

gsac aka Alex