The lake, which dates back some 3.4 billion years, appears to have covered as much as 80 square miles and was up to 1,500 feet deep, said the team from the University of Colorado.,” said Boulder's research associate, Gaetano Di Achille, in a study published in the latest edition of Geophysical Research Letters.which appears to have formed about 3.4 billion years ago.”
Analysis of the images has shown the water carved out the canyon(溪谷) in which it was found, which then opened out into a valley depositing(使淤积) sediment(沉积物) which formed a delta(三角洲)., said assistant professor Brian Hynek, adding it showed the lake existed at a time when Mars was thought to have been cold and dry. date from the Hesperian era and postdates the end of the warm and wet period on Mars by 300 million years, according to the study.网zzstep.com]
Scientists believe deltas next to the lake may well hold secrets about past life on Mars as such places on Earth have become the natural deposits of organic carbon and other markers of life.
16.The size of the lake found on Mars is ________.
A.80 square miles
B.1,500 square miles00 million square miles
17.When the lake existed, the weather on Mars was ________.
A.hot and wet
B.wet and warm
C.cold and dry
D.cold and wet
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