air mass alfred wegener institute for polar and marine research alma mater american association of petroleum geologists arthur holmes asteroid astronomy berlin blizzard bremerhaven climatology continent continental drift england franz kossmat geographical pole geologist geology george gaylord simpson germany gondwana greenland heart failure impact crater jet stream land bridge laurasia leipzig mechanism meteorology moon ocean pangaea plate tectonics roberto mantovani scientist seafloor spreading supercontinent united kingdom university of marburg wadati-benioff zone weather balloon wikimedia commons