The meteorite also was heated, perhaps as recent as during entry in Earth's atmosphere. In Sutter's Mill, the liquid water appears to have destroyed the silicate type of these, according to Xuchao Zhao of the Chinese Academy of Sciences, working with NASA and UC Davis colleagues. In primitive meteorites like Sutter's Mill, some grains survive from what existed in the cloud of gas, dust and ices that formed the solar system. "It is possible that radioactive compounds in the meteorite's parent body heated the nascent planet to the point that water ice became liquid." "We determined that minerals such as calcium and magnesium carbonate likely precipitated from liquid water 2.4 to 5.0 million years after the formation of the solar system," says Jilly. Based on isotopes of the elements manganese and chromium, NASA Earth and Space Science Fellow Christine Jilly and colleagues now report when that happened. Some fragments escaped alteration by liquid water, while others where heavily altered. "The formation of the solar system did not fully erase and homogenize these signatures and Sutter’s Mill provides the clearest record yet," said Yin, also a co-lead of the Sutter’s Mill Meteorite Consortium. They found that at least five different stellar sources composed of mixtures of 54-chromium-rich and -poor materials must have contributed matter to the nascent solar system four and half billion years ago. Some of these materials remained in the Sutter's Mill meteorite. University of California (UC), Davis researchers Akane Yamakawa and Qing-Zhu Yin studied the different forms of the element chromium, called isotopes. "Bits and pieces that originated in the interior of other much larger parent bodies." "We suspect that these diamonds are so-called xenoliths,” says Kebukawa. The larger diamonds found in Sutter's Mill may have had another origin closer to home. Nanodiamonds are thought to originate in the atmospheres of stars. ![]() "The two 10-micron diamond grains we found in this meteorite are too small to sparkle in a ring," said Mike Zolensky, space scientist of Johnson, working with associate professor Yoko Kebukawa late of Hokkaido University, Japan, "But their size is much larger than the nanometer-sized diamonds commonly found in such meteorites." ![]() In his search, Jenniskens was guided by Marc Fries of NASA's Johnson Space Center, in Houston, who describes in detail how Doppler weather radar enabled the rapid and pristine collection of the meteorites. Jenniskens found one of the first and one of the most unusual of the Sutter's Mill meteorites before rain hit the area. "From what falls naturally to the ground, much does not survive the violent collision with Earth's atmosphere." "Sutter's Mill gives us a glimpse of what future NASA spacecraft may find when they bring back samples from a primitive asteroid,” said consortium lead Peter Jenniskens of the SETI Institute in Mountain View, California, at NASA’s Ames Research Center in Moffett Field, California. They report their results in thirteen papers in the November issue of Meteoritics & Planetary Science. Researchers digging deeper into the origins of the Sutter's Mill meteorite, which fell in California's Gold Country in 2012, found diamonds and other "treasures" that provide important new insight into the early days of our solar system.
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