By Jose Cortazar
MERIDA, Mexico (Reuters) - A prehistoric crater left by anasteroid collision in Mexico's Yucatan Peninsula could yieldclues about what Mars was like billions of years ago, a NASAscientist says.
NASA planetary geologist Adriana Ocampo is digging up rocksburied deep under southeastern Mexico for hints about whatimpact craters can reveal about planet formation, and says herwork could shed light on a giant crater on the surface of Mars.
Astronomers have been puzzled for decades about a huge denton the surface of Mars -- the largest known crater in the solarsystem -- and new evidence last month suggests it was caused bythe impact of an asteroid the size of the moon.
The Mexican crater, known as Chicxulub, was created when anasteroid that smacked into Earth 65 million years ago in acatastrophe that wiped out around half the planet's species andwas maybe responsible for the dinosaurs becoming extinct.
Studying the debris spewed by the collision may answerquestions about radical changes in atmosphere that can resultfrom massive asteroid hits, Ocampo, a Colombian based at NASA'sJet Propulsion Laboratory in California, told Reuters. She hasbeen studying the Yucatan crater for a decade.
"It's a natural laboratory because of its similarities towhat we can find on other planets like Mars where humans can'tgo," Ocampo said of Mexico's smaller crater.
The crater on Mars, measuring 5,300 miles across, is so bigthat it has left half the planet at a lower elevation.
Mexico's crater is a much smaller 100 miles in diameter andis now half a mile underground, where rocks and earth haveburied it over millions of years. Space geologists believe theasteroid hit in the Caribbean Sea, probably causing a hugetsunami.
Information from Chicxulub could also give clues aboutwhether or not there was water on the surface of Mars longafter the planet was dented by the massive asteroid hit.
Scientists have detected frozen water on the surface of thered planet. Martian seas could have disappeared when the planetwas bombarded by smaller meteors that changed its atmosphereand dried it out, Ocampo said
She is looking for similarities between the Yucatan crater-- formed when southern Mexico was under the sea -- and smallercraters on Mars to see if she can detect similar patternsformed by water.
(Writing by Mica Rosenberg, editing by Jackie Frank)
