Mudstone for silt (63 μm). On December 13, 2016, NASA reported further evidence supporting habitability on the planet Mars as the "Curiosity" rover climbed higher, studying younger layers, on Mount Sharp. Also reported, the very soluble element boron was detected for the first time on Mars. In June 2018, NASA reported that "Curiosity" had detected kerogen and other complex organic compounds from mudstone rocks approximately 3.5 billion years old. Mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Grain size is up to with individual grains too small to be distinguished without
Curiosity (rover) ("Mount Sharp"), at the center of the wide crater. Thus, it is believed that the rover may have the opportunity to study two billion years of Martian history in the sediments exposed in the mountain. Additionally, its landing site is near an alluvial fan, which is hypothesized to be the result of a flow of ground water, either before the deposition of the eroded sediments or else in relatively recent geologic history. According to NASA, an estimated 20,000 to 40,000 heat-resistant bacterial spores were on "Curiosity" at launch, and as much as 1,000 times that number may not have been