Word: lavas
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...stretches as far south as the mouth of the Zambesi River. To Tazieff, however, it is an illustration of a more intriguing phenomenon: continental drift. After years of debate, scientists have finally become convinced that the earth's huge land masses are really moving. As they see it, lava is pouring out of a 47,000-mile-long chain of volcanically active ridges that cut through the oceans. The lava spreads from the undersea rifts and carries the continents along with it (TIME...
...meeting place of three such giant rift systems. Two of these cleave the Red Sea and the Gulf of Aden, and geophysicists think that both bodies of water are gradually being widened into oceans at the rate of perhaps an inch or so a year as the lava pours out of the rifts...
Tazieff contends that the Afar triangle is, geologically speaking, a section of the expanding floor of the Red Sea. That floor, he says, has been uplifted by earthquakes, volcanic eruptions and other activity linked with lava flows from the Red Sea rift-whose axis has somehow been displaced slightly westward in the area of the triangle (see diagram). But the uplifting is only temporary, he writes in Scientific American. Only tens of thousands of years ago, a fleeting moment by geological standards, the Afar triangle was partially covered with seawater. As the Red Sea continues to widen and the subsurface...
...similarities to specimens found on the ocean floor. For another, the desert regions of the Afar triangle are covered with a thick layer of evap-orites, the salty debris left behind after seawater evaporates. Tazieff and his colleagues also found distinct traces of coral in the area's lava beds, plus a Stone Age ax that was actually encrusted with seashells-a sign that the relic was once covered by seas...
...Examination of the lunar rocks also established that catastrophic events rocked the moon about a billion years after its creation. "There were definitely lava flows 3.65 billion years ago," says Wasserburg. Scientists are still uncertain whether the lava rose from a hot lunar interior or was created by heat from the impact of huge meteorites. If the melting was indeed caused by meteors, a similar process might have occurred on the nearby earth. This could explain why scientists have been unable to find any terrestrial rocks older than 3.6 billion years-although the earth, too, is believed...