DRISCOLL, Rhonda L.¹, BENZEL, William F.², DIEHL, Sharon F.³, HAGEMAN, Philip L.⁴, MORMAN, Suzette A.⁴ and CHOATE, LaDonna M.⁵, (1)U. S. Geological Survey, Denver Federal Center, MS 973, Denver, CO 80225, (2)U.S. Geological Survey, Box 25046, Mail Stop 964, Denver Federal Center, Denver, CO 80225, (3)U. S. Geological Survey, Denver Federal Center, MS 964, Denver, CO 80225, (4)U. S. Geological Survey, Denver Federal Center, MS 964D, Denver, CO 80225, (5)U. S. Geological Survey, Denver Federal Center, MS 939, Denver, CO 80225, rdriscoll@usgs.gov, rdriscoll@usgs.gov

ORAZULIKE, Donatus, Geology Program, Abubakar Tafawa Balewa University, P.M.B. 0248, Bauchi, Nigeria, dorazulike@yahoo.com, dorazulike@yahoo.com

TANG, Fanny, Geosciences Department, Wellesley College, 106 Central Street, Wellesley, MA 0248 and BRABANDER, Daniel J., Geosciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, tang.fanny.506@gmail.com, tang.fanny.506@gmail.com