sentences:  The deposit was formed 250 million years ago during the eruption of the Siberian Traps igneous province (STIP).The STIP erupted over one million cubic kilometres of lava, a large portion of it through a series of flat-lying lava conduits lying below Norilsk and the Talnakh Mountains.The Siberian Traps are considered to be responsible for the mass extinction event at the end of the Permian.