「首发」沃邦名师3月10日亚太SAT考试考情速递(18)

Scientistsalready know that the Procellarum region is rich in radioactive elements thatbillions of years ago would have produced excess heat. The study team theorizesthat as this region cooled, the rock would have cracked in geometricalpatterns, like honeycomb patterns seen on Earth in basalt formations, but on amuch larger scale. In a study published today in Nature, the researcherspropose that these cracks eventually grew into rift valleys, wheremagma from the moon’s mantle welled up and pushed apart blocks of crust. Lava spilledout and paved over the Oceanus Procellarum, creating the dark spot that is seentoday. The extra weight of this dense material would have caused the wholeregion to sink slightly and form the topographic low that has made theProcellarum seem like a basin.
With thediscovery, the moon joins Earth, Mars, and Venus as solar system bodies withmapped examples of rifting. There are also similar features near the south poleof Enceladus, the moon of Saturn that is spewing water into space from cracksin an ice shell.