STEIN, Carol A., Earth & Environmental Sciences, University of Illinois at Chicago, 845 W. Taylor St, m/c 186, Chicago, IL 60607-7059, cstein@uic.edu, STEIN, Seth, Earth and Planetary Sciences, Northwestern University, 1850 Campus Drive, Evanston, IL 60208-2150, MERINO, Miguel, Department of Earth and Planetary Sciences, Northwestern University, 1850 Campus Drive, Evanston, IL 60208, KELLER, G. Randy, School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, and FLESCH, Lucy M., Department of Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906