Why the USSR Stopped Drilling at 12,262 Meters Came Down to an Unexpected Limit
Key TakeawaysThe Soviet Union’s SG-3 Kola borehole hit a record 12,262 meters in 1989, short of its 15 km goal.Core samples at Kola upended seismic models, finding no expected granite-to-basalt boundary at depth.Heat near 414°F made rock flow and squeeze...










