Michel Gregoire

RESEARCH FIELD

Petrology, Mineralogy and Geochemistry of the deep lithosphere (lower crust and upper mantle)

Key words: Petrology, Mineralogy, Geochemistry, Magmatism, Ultramafic-mafic rocks, Mantle xenoliths, Ophiolites, Peridotites, Gabbros, Oceanic granulites, Cumulates, Mantle Metasomatism, Underplating processes, Crustal thickening, Continental nucleii,

I have broad interests in petrology, mineralogy and geochemistry, with my greatest enthusiasm being in the study of magmatic and mantle ultrabasic and basic rocks. I study those ultramafic and mafic rocks in various types of occurrences such as xenoliths in basalts and kimberlites, ophiolites, orogenic lherzolitic massifs and layered intrusions. I am undertaking collaborative works on numerous areas in the world (Patagonia, Kerguelen Islands, Philippines, French Massif Central, Poland, Germany, Algeria, Oman, California, Spain, Antarctica, Cameroon and South Africa). All these studies are focusing on the nature and evolution of the magmas and metasomatic melts percolating and accumulating within both the oceanic and sub-continental upper mantle and lower crust both in intraplate and subduction zone settings. For that purpose, I use detailed analyses of major and trace element contents in both bulk rocks and minerals using electron microprobe, and ICP-MS techniques (laser and solution). The final goal of all these studies is to better understand the nature and the evolution of the lower crust and the upper mantle in various settings, and in particular to better understand the nature and evolution of the crust-mantle boundary and the chemical exchanges taking place between these two major earth reservoirs.