| The subeconomic Torrie, Sputnik and Eddie pipes, located near Yamba Lake, central Slave province, NWT, are diatreme-facies macrocrystic, heterolithic, volcaniclastic kimberlite breccias. Major-element chemistry of pyroxene and garnet xenocrysts and megacrysts in the Torrie and Sputnik kimberlites is consistent with their derivation from disaggregated garnet lherzolite and high temperature deformed lherzolite, with minor contributions from eclogite, spinel lherzolite, garnet harzburgite and websterite. The presence of primary phlogopite and more evolved spinels, and the lack of mantle xenocrysts, xenoliths and megacrystic ilmenite distinguish the Eddie kimberlite pipe from the Torrie and Sputnik pipes.;Large variations in ;The Torrie and Sputnik kimberlite pipes have diamond indicator minerals consistent with their low diamond grades; however, transient-heating events may have also played a role in their reduced diamond contents. High temperatures and metasomatism just prior to eruption of the kimberlites may have caused the resorption of diamonds. |
