1. U.S. Geological Survey and Department of Earth Sciences, University of California, Riverside, California 92521, USA
2. Stewart Lithia Mines, P.O. Box 382, Pala, California 92059, USA
3. U.S. Geological Survey, Spokane, Washington 99201, USA
4. Department of Earth, Environmental, and Planetary Sciences, Rice University, Houston, Texas 77005, USA