Following are highlights from the October issue of GEOLOGY and a summary of the science article from the October issue of GSA TODAY, published by the Geological Society of America. Stories written regarding these articles are embargoed until October 1. We ask that you discuss articles of interest with the authors before publishing stories on their work, and that reference be made to GEOLOGY or GSA TODAY in stories published. Please contact Ann Cairns at GSA to request advance copies of articles and for additional information or assistance.

GEOLOGY

Oceanside and Thirtymile Bank blind thrusts: Implications for earthquake hazards in coastal southern California. Carlos Rivero et al.
This article defines a new blind-thrust system in coastal southern California that threatens the Los Angeles and San Diego metropolitan regions. An integrated approach documents recent activity in the blind thrusts by combining geophysical, seismological, and coastal tectonics studies with three-dimensional structural modeling. These thrusts originated as Miocene normal faults, suggesting that positions of pre-existing structures may control modern blind-thrust systems. The new fault system yields plausible scenarios for large (M 7.17.6) but infrequent earthquakes.

Grenville-age basement provinces in East Antarctica: Evidence for three separate collisional orogens. I.C.W. Fitzsimons.
The continents on Earth have periodically amalgamated to form supercontinents as they drift across Earth's surface, and each of these amalgamation events has produced a network of collision zones marked by elongate belts of deformed and metamorphosed rock. The supercontinent of Rodinia is widely believed to have assembled some 1000 million years ago along the so-called "Grenville-age" metamorphic belts, including the Grenville Province of eastern North America and the Circum-East Antarctic Mobile Belt. These Grenville-age belts are
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Geological Society of America
24-Sep-2000