Spherules in Yellowknife Bay, Curiosity sol 139 (December 25, 2012)

Spherules in Yellowknife Bay, Curiosity sol 139 (December 25, 2012)
Spherules in Yellowknife Bay, Curiosity sol 139 (December 25, 2012) The "Sheepbed Unit" of rock that forms the floor of Yellowknife Bay often contains roughly spherical features. These are called spherules. These features are interpreted as concretions, implying they formed in water that percolated through pores in the sediment. Spherical concretions have previously been discovered in other rocks on Mars. NASA / JPL / MSSS