Word: lava
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Dates: during 1990-1999
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This intriguing fact, say project scientists, is a strong hint that the mountain has recently been covered with lava. Rock that sits on the surface of mountaintops appears to weather quickly in the hot, chemically reactive atmosphere, creating a soil that is rich in iron sulfide. It is this mineral, the scientists believe, that shows up easily on radar. If Maat Mons doesn't have any, it has presumably been resurfaced, perhaps within the past few years...
...which indicate that molten rock, called magma, is coming up from deep inside the earth. The magma rises gradually, opening fissures that serve as its pipelines to the surface. What happens next depends on the composition of the magma. If it is fairly liquid, it generally produces a stately lava flow that poses more of a threat to property than to humans. Hawaiian volcanoes tend to follow this pattern...
...Last week NASA's Magellan spacecraft transmitted the most detailed pictures ever made of Earth's next-door neighbor. The radar images revealed a tortured topography with fault-like cracks in surprisingly regular patterns, craters as big as greater Los Angeles and volcanic mountains flanked by congealed rivers of lava at least 320 km (200 miles) long. Says James Head III, a Brown University geologist and member of the Magellan imaging team: "It's a revolutionary new view of Venus...
...Venusian volcanoes are still capable of erupting, and there is even a chance they may be caught in the act. After finishing a 243-day mapping mission, Magellan will start all over and do it again. Any change in the landscape that shows up in the second version -- new lava or other debris, for example -- would be strong evidence of volcanism, making Venus only the fourth body in the solar system, after Earth, Jupiter's moon Io and Neptune's moon Triton, where eruptions have been spotted...
After a balky start, the Magellan probe is mapping the cloud-shrouded planet by radar. Found so far: giant craters, major lava flows and a webwork of faults...