strange built structures in african lakebed

strange, artificial structures (dim square shape and barred, circular formation) come to surface at low water level. (check timeslider for previous water levels)

oil mining operations 5 miles SE to placemark is not enough explanation (for me), for what are (were) these near the bottom of this depression?  

the one just below the marker somewhat resembling to old, african settlement walls or those often mentioned saudi and african stone structures, also rectangular shape at 10 o'clock is no imagery glitch.




any ideas?

thanks!

g

Lakebed structures.kmz (890 B)

This it a artificial pond for Zelten Oil Field. Probably not historical objects.

more precisely: it is an artificial water stand in a natural depression, which naturally would be dry and empty, so as it was in historical times. (!)

I wish my lottery-5 would be as sure as it is an ancient structure! (:

(50%)

Not as for the straight-linear one above placemark, which has better odds by me to be a newborn construction.