2002 Denver Annual Meeting (October 27-30, 2002)

Paper No. 12
Presentation Time: 8:00 AM-12:00 PM


MOONEY, Walter D.1, CHULICK, Gary2 and DETWEILER, Shane1, (1)U.S. Geol Survey, 345 Middlefield Rd. MS 977, Menlo Park, CA 94025, (2)St. Xavier Univ, Chicago, IL 60655, mooney@usgs.gov

Thorough knowledge of the Earth’s crustal structure is necessary for understanding continental evolution and other geological processes. We present a recently updated contour map of the thickness of the Earth's crust using a 10-km contour interval, and the 45-km contour. This contour map was created from over 5000 individual crustal data points that have been acquired during the past 60 years. The contour map honors all available seismic refraction measurements for features with a dimension greater than 2 degrees. Crustal thickness in Eurasia, North America, and Australia is well constrained by seismic refraction data, while Antarctica, South America, Africa, and Greenland are less well constrained. To a first approximation, the continents and their margins are outlined by the 30-km contour. The part of the continental interior enclosed by the 40-km contour and regions with crustal thickness of 45 to 50 km are found on all well-surveyed continents. Continental crust with thickness in excess of 50 km is exceedingly rare and accounts for less than 10% of surveyed continental crust. These observations, now available on a global basis, provide important information to be used for numerous scientific studies.