blivet radio
The Radio weblog of Hal Rager

Saturday, July 6, 2002

Saint Louis University Geologist's Discovery May Unlock Secrets To Start Of Life On Earth "Tim Kusky, a professor of Earth and atmospheric sciences, has discovered the world's first large intact pieces of oceanic mantle from the planet's earliest period, the Archean. The nearly mile-long section of rock, which is billions of years old, may hold clues as to when life developed on the planet. (...) This latest discovery may prove even more remarkable. For years, scientists have longed to find large pieces of the planet's deep interiors. But until now, they've had to rely on only tiny fragments to study. Formed tens of kilometers below the ancient sea floor, this new discovery's massive mantle rocks are preserved in a highly faulted belt 100 kilometers long. Unlike the sea floor samples Kusky found last year, the mantle rocks preserve 2.5 billion-year-old minerals that hold clues to the origin of plate tectonics. The minerals, including an unusual type of chromite deposit only known from deep ocean floor rocks appear to have been deformed at extremely high temperatures before they were completely crystallized by volcanic magma. This shows that the mantle rocks were flowing away from the ridges on the oceanic floor, evidence that the continents began shifting more than 500 million years earlier than now widely believed. Because the discovery shows that the plates were moving in that early period, these findings could have a more far-reaching effect on theories related to the development of life on the planet. Just when single-celled organisms evolved into more complex organisms has been contested for years. Because hot volcanic vents on the sea floor may have provided the nutrients and temperatures needed for life to flourish, Kusky said it's possible that life developed and diversified around these vents as the plates started stirring. (...)" [Science Daily] 12:05:29 AM    comment   trackback []