Kimberlites are a rare and poorly understood form of volcano originating at great depths within the Earth. Unfortunately, their extreme nature makes them very fragile under surface conditions, and they quickly decay, a problem that conventional analytical techniques have been unable to overcome. By using a laser to drill holes of less than 0.1 mm in diameter, Paton et al. targeted particular minerals (perovskites) within the rock that are virtually immune to these weathering effects. These tiny crystals preserve reliable information about the composition of the magma that formed the volcano, providing new insights into kimberlite formation. The new strontium isotope data obtained from perovskites during this study suggest that kimberlites form at depths of hundreds of kilometers below the Earth surface and travel to the surface directly, without mixing with rocks of the Earth's crust. If this is the case, they may act as a "window" to the deep Earth, allowing us to better understand the processes at work deep within the mantle.
Age variation of pore water iodine in the eastern Nankai Trough, Japan: Evidence for different methane sources in a large gas hydrate field
Hitoshi Tomaru et al., Kitami Institute of Technology, New Energy Resources Research Center, Hokkaido 090-8507, Japan. Pages 1015-1018.
Gas hydrate is a large natural gas reservoir found commonly in marine sediments. Because of its high potential as a gas resource in the future and environmental impacts through Earth's history, an increasing number of scientific and industrial expeditions have been carried out to characterize gas hydrate occurrence and related geological phenomena. Tomaru et al. measured the concentration of a long-lived radioisotope of iodine (129I) in pore waters from the eastern Nankai Trough, offshore the main island of Japan, in order to determine the potential age of iodine as a
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Geological Society of America