July 2008 GEOLOGY and GSA Today media ...( Boulder CO USA - GEOLOGY topics sp...)

Boulder, CO, USA - GEOLOGY topics span the globe and beyond, covering southern Africa's diamond kimberlites, sandstones and shales of Scotland, a "Greenhouse World" in the Wyoming badlands, glacial erosion in East Greenland, oxidation of methane in southern Namibia, preservation of woolly rhinoceroses in Ukraine, gold nanoparticles in Australia, and the possibility of a water-rich environment in Mars' past. GSA TODAY contains the first authoritative geological and geophysical treatment of the 12 May 2008 earthquake in Sichuan Province, China.

Ghosts of lithospheres past: Imaging an evolving lithospheric mantle in southern Africa

Alan F. Kobussen et al., GEMOC, Dept. of Earth and Planetary Sciences, Macquarie University New South Wales 2109, Australia. Pages 515-518.

Kimberlites--volcanic rocks that can carry diamonds to the surface--bring up samples of rocks and minerals from the ancient continental roots, 100-200 kilometers beneath Earth's surface. In southern Africa, two episodes of volcanism 10-15 million years apart provide "snapshots" in two different time slices of this otherwise inaccessible part of Earth. Chemical fingerprinting of minerals in these deep roots has revealed dramatic changes in the composition and structure of the continental root caused by the infiltration of magmas from deeper in the Earth over this short period. Continental roots like the one in southern Africa can remain stable for billions of years, but they also can evolve through time. Kobussen et al. provide new insights into the processes that can modify and potentially destabilize the continental roots.

Ancient Laurentian detrital zircon in the closing Iapetus Ocean, Southern Uplands terrane, Scotland

John W.F. Waldron et al., Dept. of Earth and Atmospheric Sciences, 1-26 Earth Sciences Building, University of Alberta, Edmonton, Alberta T6G 2E3, Canada. Pages 527-530.

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