AGU member since 1980. Professor of Geophysics at Institute of Geophysics, National University of Mexico (UNAM), Mexico City. Major areas of interest include paleomagnetic and rock magnetic studies of igneous and sedimentary rocks applied to tectonics and stratigraphy, paleointensities and paleosecular variation of the Earth's magnetic field, gravity and crustal structure, and Quaternary paleoclimates. In the last years, interest has been focused on the Chicxulub impact crater and the Cretaceous/Tertiary boundary. Cooperation studies have been conducted with colleagues from various countries including United States, United Kingdom, Japan, Spain, Canada, Brazil, Chile, Argentina, France, Germany, Italy, India, and Thailand. Ph.D., Geophysics, 1980, University of Newcastle upon Tyne, UK. Director, Institute of Geophysics, UNAM, 1997–2005. Chairman, Department of Geomagnetism and Exploration Geophysics, UNAM, 1988–1997. Secretary–Treasurer, Mexican Academy of Sciences, 2004–2006; President, Mexican Union for Quaternary Studies, 2002–2005; President, Mexican Geophysical Union, 1986–1988; Secretary-general, Mexican Geophysical Union, 2003–2005. Member of committees for scientific assessment including Mexican Council of Research and Technology, Mexican Academy of Sciences, and International Continental Drilling Program. Thesis advisor for 40 postgraduate students. Coauthored 170 refereed publications, 18 in AGU journals. Edited special volumes for Tectonophysics, Physics of the Earth and Planetary Interiors, Quaternary International, Geofisica Internacional and Meteoritics and Planetary Science. Associate Editor of Journal of Geophysical Research, 1993–1995, Bulletin of the American Geological Society, 1999–2001, Quaternary Research, 2005, Geofisica Internacional, 1994 to present, Geologica Acta, 2002 to present, Revista Mexicana de Ciencias Geologicas, 2002 to present. Awards of the Mexican Academy of Sciences, 1991, American States Organization, 1992; Mexican Geophysical Union, 1992; National Puebla Science Award, 1988. AGU service as member of the Meetings Committee, 2004–2006; Chairman of AGU Latin-American Regional Advisory Committee, 1991–1994.