9628209 Cameron The PI's propose a combined SHRIMP and IDTIMS U/Pb zircon study of granulites from Kilborne Hole in order to get the complete and precise geochronological information required to unravel the evolution of the deep crust beneath the Rio Grande rift. The PI's will refine applications of the Lu/Hf system to dating processes such as melting and metamorphism in rocks affected by these processes. Granulite xenoliths from Kilborne Hole are ideal for these U/Pb zircon and Lu/Hf geochronology studies because (1) they are abundant and relatively large, (2) a previous Sm/Nd study by Cameron suggests that crust formation and modification can be documented over a long time interval (1700 Ma to Cenozoic), and (3) the PI's previous Lu/Hf study has demonstrated that some of the garnet-bearing granulites were affected by Cenozoic events. The quality of the data will probably be needed in general for further advances in the understanding of deep crustal processes through the study of granulite xenoliths.
