August GEOLOGY and GSA TODAY Media Highlights

New mapping of faults in the Gulf of Alaska by Gulick et al. reveal that an important response to tectonic collision of the Yakutat block into North America over the last 5 million years is the recent creation of a new plate boundary. The unusually thick Yakutat block is resisting underthrusting beneath the continent, and thus the Queen Charlotte-Fairweather fault system that stretches from British Columbia to the Denali fault in central Alaska has recently (within the last few hundred thousand years) started extending offshore to propagate strike-slip faulting at the base of the continental slope. The base of the slope in this area has been called the Transition zone or Transition fault, and has been interpreted as everything from not existing, to being a thrust fault, to being a strike-slip fault. Gulick et al.’s new bathymetry and seismic data show it to be a young strike-slip fault lying at the boundary between normal Pacific Ocean crust and the Yakutat block. This research suggests that plate boundaries may have been created similarly in the geologic past when thickened regions of crust collided with continents.

GSA TODAY Science Article

Alexandria, Egypt, before Alexander the Great: A multidisciplinary approach yields rich discoveries
Jean-Daniel Stanley et al., Geoarchaeology Program, Rm. E-206, Paleobiology, Smithsonian Institution National Museum of Natural History (NMNH), Washington, D.C. 20013-7012, USA.

Our modern western civilization traces its roots to the Mediterranean region, and determining exactly when and where civilizations took hold remains an ongoing quest. For example, the armies of Alexander the Great swept across the region, leading to the establishment of the city of Alexandria on the shores of the Mediterranean in BC 332. But what came before Alexander" Was there a settlement that preceded Alexandria, and if so, what can we learn about the people who lived and died there" These are some of the questions addressed by Jean-Daniel Stanley of the Smithsonian Institution, Washington, D.C., and his co-workers in a paper in the August GSA TODAY. By applying a multidisciplinary approach, involving archeology, sedimentology and geochemistry, to the study of sediment cores collected from Alexandria’s Eastern Harbor, Stanley and his colleagues have demonstrated that a settlement occupied the region for at least seven centuries prior to the arrival of Alexander. Ceramic shards, high lead levels, and the use of building stones imported from other regions all attest to a once flourishing urban center as far back as BC 1000. These discoveries indicate that much is still to be learned about the early development of western civilization, and an effective means of achieving this is by integrating geologic and archaeological methodologies.

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