English: This astronaut photograph highlights two river deltas formed along Lake Ayakum's south-western shoreline. Gray to tan surfaces indicate prior positions of the river channels; the uniform coloration and smooth texture suggest that they are relatively old and now inactive. By contrast, the younger and currently active delta surfaces have reddish-brown sediment and visible river channels. Lateral channel migration is particularly evident in the approximately 8-kilometer wide active delta at image upper left. The reddish color of the fresh sediment may indicate a change from the sources that formed the older parts of the deltas. It might indicate weathering and soil formation on the older deposits. It could even be a sign of episodic inputs of dust or other material to the river catchments.