Geochemical and isotopic studies of ultramafic xenoliths from West Kettle River, southern British Columbia. M.Sc. thesis

A systematic geochemical and isotopic study of ultramafic xenoliths from a Pliocene basanitoid flow at West Kettle River, southern British Columbia, has been attempted to increase our understanding of the nature and evolution of the upper mantle beneath this region. The bulk chemical variations of the West Kettle River Group I lherzolites and harzburgites seem to be largely controlled by partial melting processes. Most of these xenoliths have lower ΣFeO than xenolith suites from Summit Lake, British Columbia and San Carlos, southwestern USA, possibly a result of less interaction with migrating melts. Nd and Sr isotopic ratios of the clinopyroxenes in all but one of these lherzolites and harzburgites (0.51296-0.51335, 0.70223-0.70342) are similar to MORB. Multiple mantle metasomatism may be related to the Miocene to Recent volcanism in this region. Depleted isotopic compositions of the inferred metasomatic agents testify to the involvement of a MORB-like mantle component in their sources. -from Author