1. Department of Earth Sciences, University of Oregon, Eugene, Oregon 97403, USA
2. Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA
3. Department of Geological Sciences, Stanford University, California 94305, USA
4. Department of Geology, Western Washington University, Bellingham, Washington 98225, USA
5. Colorado Desert District Stout Research Center, 200 Palm Canyon Drive, Borrego Springs, California 92004, USA
6. U. S. Geological Survey, 2255 N. Gemini Drive, Flagstaff, Arizona 86001, USA
7. Department of Earth and Planetary Sciences, University of California, Davis, California 95616, USA
8. Devon Energy Corporation 333 W Sheridan Avenue, Oklahoma City, Oklahoma 73102, USA