Shallow Mantle Composition and Dynamics: Fifth International Orogenic Lherzolite Conference: Foreword

Abstract

The First International Orogenic Lherzolite Conferencewas held in Montpellier, France, in 1990 (Menzies et al.,1991). Subsequent Orogenic Lherzolite Conferences wereheld in Granada, Spain in 1995, Pavia, Italy in 1999 andSamani, Japan in 2002. Avital aspect of all these meetingswas the opportunity to visit nearby exposures of mantleperidotites: to date, participants have visited Lherz inFrance; Baldissero, Balmuccia, Erro Tobio, Finero, Lanzoand Liguria in Italy; Ronda in Spain; Beni Bouserain Morocco; and Horoman in Hokkaido, Japan.Peer-reviewed papers from all four conferences were pub-lished in theJournal of Petrology in 1991, 2001and 2004 and,in one instance, in Chemical Geology in1996.The Fifth Lherzolite Conference was held in ShastaCity, California in September 2008. The conference wassponsored as a Chapman Conference by the AmericanGeophysical Union (AGU), which also provided locallogistical assistance. Funding for participants was providedby the AGU, US NSF Ridge Program, the NSF EarthSciences Division, the US Science Support Program of theConsortium for Ocean Leadership, the Royal Society UKand the Lithosphere^Asthenosphere Interactions taskforce of the International Lithosphere Program. Present,from14 countries, were108 attendees including 36 studentsand 11 postdoctoral researchers. Sixty-six oral presenta-tions and 67 posters were presented during the 5day meet-ing. As is the tradition, field trips to classic mantleperidotite localities were incorporated into the program,including a pre-meeting trip to the Josephine peridotiteled by Peter Kelemen, Henry Dick, and Greg Hirth forabout 50 people; a mid-week field trip for all participants,led by Tim Grove and Christy Till; and a 2day,post-meeting trip to the Trinity peridotite for about 50people, led by Peter Kelemen, Francoise Boudier, andKolya Stremmel.The Fifth Lherzolite Conference covered a broaderrange of topics than previous meetings, including carbonsequestration in the mantle and low-temperature hydro-thermal alteration. Underlying the presentations was therealization that previous distinctions between ‘orogenic’peridotites (e.g. Lanzo Massif, Italy), and ‘ophiolitic’peri-dotites (e.g. Troodos, Cyprus; Josephine, Oregon) and‘abyssal’peridotites from ocean ridges were in need of revi-sion. It now appears that a continuum exists fromsub-continental to oceanic mantle exposed in some com-plexes (e.g. Lanzo; Bodinier et al., 1991; Piccardo et al.,2007; Mu«ntener et al., this issue), and that much ocean