September Geology and GSA Today media ...(d between 140000 and 110000 years ago. T...)

Date:8/28/2007

d between 140,000 and 110,000 years ago. The climate during this time consisted of episodic wet events that enabled the deserts of the northeastern Sahara, Sinai, and the Negev to become more hospitable for the movement of early modern humans. The simultaneous occurrence of wet periods in the northern and southern parts of Saharan-Arabian desert could have led to the disappearance of the desert barrier between central Africa and the Levant. The humid period in the Negev Desert between 140,000 and 110,000 years ago was preceded and followed by essentially unbroken arid conditions; thus creating a climatic "window" for early modern human migration to the Levant. Vaks et al.s study suggest that climate change had an important limiting role in the timing of dispersal of early modern humans out of Africa.

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Neotethyan Late Cretaceous volcanic arc hydrothermal vent fauna
Crispin T.S. Little, University of Leeds, School of Earth and Environment, Leeds, West Yorkshire LS2 9JT; UK; et al. Pages 835-838.

Deep-sea hydrothermal vents support communities of animals that depend on hydrogen sulphide, rather than sunlight, for their energy. Many of the most dominant animals in these communities have symbiotic relationships with bacteria, including giant tube worms. Ancient vent communities are very rare, but provide important insight into biological evolution in this challenging ecosystem. Little et al. decribe a newly discovered Cretaceous vent community from a metal ore deposit in the Republic of Georgia, which is the first to be identified from an ancient volcanic arc setting, and is very likely the shallowest ancient example yet found. The fauna consists of worm tube fossils and is one of three examples that occurred over a time span of roughly 6 million years in an area of the Neotethyan Ocean that was as tectonically complex as the present day west Pacific Ocean.

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Supercontinent cycles disrupted by strong mantle plumes
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Contact: Ann Cairns acairns@geosociety.org 303-357-1056 Geological Society of America Source:Eurekalert

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