Support for the Penrose Conference on Arc Crustal Genesis and Evolution; July 9-15, 2006; Valdez, Alaska

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

0632774 Hacker This award provides partial support for a Penrose Conference on arc crustal genesis and evolution which will be held in Valdez, in south-central Alaska, from July 9-15, 2006. Presentations will integrate recent results on well-exposed arc crustal sections in the Jurassic Talkeetna arc in south central Alaska, and in the Cretaceous Ladakh-Kohistan arc in northern Pakistan and India with important new developments in active-arc geochemistry, petrology and geophysics. The Talkeetna and Ladakh-Kohistan arcs provide exposures of relatively complete sections from Moho depth (30 to 40 km in both cases), to volcanic rocks and volcaniclastic sediments. Both have been the subject of large, multi-disciplinary Continental Dynamics Program (CD) projects over the past decade, and provide depth sections and temporal progressions that are not accessible in active oceanic arcs. Intensive, recent investigations of arc plutonic suites elsewhere complement these projects. New data from the US MARGINS Initiative, Sierra Nevada Continental Dynamics Projects, Aleutian studies, and similar international initiatives provide constraints on crustal thickness and volcanic fluxes in active arcs. Advances in the study of melt inclusions have dramatically improved understanding of volatiles in primitive arc magmas. Studies of ultra-high pressure metamorphic rocks and new experimental methods have yielded insights into mantle wedge melt generation, and subduction zone dehydration and anatexis. This conference will provide an opportunity to synthesize these results, with a focus on using direct observations of arc crustal sections, from the uppermost mantle to the volcanics, to constrain arc processes and their role in the genesis and evolution of continental crust. The enthusiastic response of keynote speakers, only one out of twenty-four declined the request for letters of commitment, indicates that the time is right for this conference, and that it will attract an excellent group of well informed participants with much to discuss. To complement research presentations, the Conference will include at least two field trips, to accessible outcrops of volcanic and the Moho sections of the Talkeetna arc.