'Black Beauty' Meteorite Study Reveals the Secrets of Mars' Strange Topography
Back in 2011, a Martian meteorite was found in the Sahara Desert. The official name of the 320-gram rock is Northwest Africa (NWA) 7034, but it is also known by the nickname "Black Beauty." Scientists knew from previous studies of rock samples from Mars that Black Beauty was special, and now, thanks to a recent study by researchers at the Lawrence Livermore National Laboratory, more secrets about how and when the planet's crust formed have finally been unlocked.
NWA 7043 is an example of breccia, which means that it is made up of different kinds of rocks that were mixed and fused together by heat (sintered). Its unique makeup allowed the researchers to learn more about the Mars' crust than they could from a rock collected from the surface.
Using various chronometry methods (the science of time measurement), researchers were able to determine the approximate age of the meteorite at 4.4 billion years old.
They also were able to form new theories about how the northern and southern hemispheres of the planet (each with a different crust thickness and terrain) were formed.
"If the Martian crustal dichotomy formed as a result of a giant impact, and available data and modeling suggest this is likely, the history of NWA 7034 requires that it formed very early in the planet's history, before 4.4 billion years ago," said cosmochemist Bill Cassata, lead author of the study.
And the breakthroughs from the study don't stop there. Not only were researchers able to prove that the meteorite formed from different rocks about 200 million years ago—the rock's age revealed that the dichotomy of Mars' topography was created longer than 4.4 billion years ago because otherwise the "dichotomy-forming event" would have buried rocks near the surface of the planet or entirely destroyed them.
"This multi-disciplinary study, combining both traditional and innovative geochemical techniques has provided us with some exciting new insights into the timings of major processes that shaped young Mars," said Caroline Smith, head of Earth sciences collections and principal curator of meteorites at the Natural History Museum.
"We have been able to unpick the different ages and different geological processes recorded in this highly complicated rock. Although the sample is in itself small, and the individual fragments we measured are tiny, we have been able to peek into the past and gain a glimpse of approx. 4.4 billion years of Mars' history."