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In the west of the area (on the upper edge of the image – north is to the right) conspicuous, irregularly shaped light-coloured blocks are visible. These features are up to two kilometres in size and are probably large rock fragments or mounds of rock. However, the mechanism of their formation is still being debated. One possibility is that the top layer of rock was shattered by the shockwaves from an impact.
Another possible explanation would be a process known as subrosion, where material is removed from layers beneath the surface. On Mars, subrosion is widely observed when rising magma heats frozen ground water, which melts and removes subsurface material as it flows away. This leads to a honeycomb of cavities that eventually collapse due to the weight of the overlying rock layers, leaving the irregular mounds standing. The bright surface is probably due to the fact that wind has removed the overlying dust and sand and exposed the bare rock surface.
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