A special two-day symposium of the IV International Conference on Advanced Materials, entitled "Planetary Impact Events: Materials Response to Dynamic High Pressure," will be held in Cancun, Mexico, August 27- September 1, 1995. The participants will explore issues related to the shock-induced modification of minerals during natural impacts to better understand planetary impact processes.

Symposium topics will include Cratering Processes; Chicxulub Impact and the K/T Extinction; Diaplectic Phases; Experimental Shock-Loading; Impact-induced Hydrothermal Alteration of Minerals; Mineralogical Changes During Impact; Modeling Planetary Impacts; and Spectroscopy of Shocked Materials. Organizing Committee members are Laura J. Crossey, University of New Mexico, Albuquerque; Randall T. Cygan, Sandia National Laboratories, Albuquerque; and Luis Ernesto Marin Stillman, Universidad Nacional Autónoma de México, México City.

Abstract deadline for the meeting is May 31, 1995. For additional information and abstract forms contact Randall T. Cygan, Geochemistry Department, Sandia National Laboratories, Albuquerque NM 87111-0750. Phone: 505-844-7216; fax: 505-844-7216; e-mail:

The Ames Structure and Similar Features-A Workshop

Co-sponsored by the Oklahoma Geological Survey and Bartlesville Project Office of DOE, the workshop will be held March 28-29, 1995, in Norman at the Oklahoma Center for Continuing Education. The Ames structure, located on the Anadarko basin shelf in northwestern Oklahoma, is a prolific source of oil and gas with more than 50 producing wells. Discovered in 1991, it is a circular structure buried beneath more than 9000 feet of sediments. It is 6-10 miles in diameter with relief of about 600 feet. Ames has been interpreted as a meteorite impact crater, a volcanic caldera, or a solution/collapse feature. The event occurred in Early Ordovician time and influenced structure and sedimentation throughout the remaining Paleozoic Era, and possibly through Recent geologic time.

With an anticipated attendence of 200-300, the workshop will feature 24 oral presentations and 16 informal posters and displays. Program topics include craters in the solar system, terrestrial craters, geochemistry, crater recognition, and hydrocarbon potential. Topics on the Ames structure include exploration techniques, remote sensing, petrology, mineralogy, geochemistry, petroleum production, trapping mechanisms, reservoir characterization, source-rock facies, oil characterization, Landsat MSS, TM imagery, 3-D seismic imaging, phyllocarid crustaceans, basement rocks, gravity/magnetic modeling, shocked quartz, as well as evidence and interpretations for meteorite impact, volcanic, or dissolution-collapse origin of the structure. Reports on similar structures will include Marquez Dome, Wells Creek, Chicxulub, Haswell Hole, Calvin, Big Basin craters, Kentland Dome, Red Creek, and a 3000-year-old crater in central Nebraska.

For information, contact Ken Johnson or Jock Campbell, Oklahoma Geological Survey, University of Oklahoma, 100 E. Boyd, Room N-131, Norman OK 73019. Phone: 405-325-3031; fax: 405-325-7069.