(Flooded) Perched Playa

A small basin improbably perched about 400 ft (120 m) above the main basin. It's relict topography from when the whole Black Rock basin was filled with a huge lake, Pleistocene Lake Lahontan, several hundred feet deep. The barrier walling off this little basin is a spit, a peninsula (highlighted) deposited by longshore drift when Lake Lahontan was full.
In fact, there are lots of small perched playas and similar features around Lake Lahontan, formed by shoreline processes in a deep lake. In some places, the Lake Lahontan features are so large-scale they're a good model of marine shoreline processes, showing what the coastline would look like if you could drop sealevel a few hundred feet. (As it happens, I have a whole album on such a place, where we would take Geology 100 students on field trips: www.ipernity.com/doc/289859/album/501179)

Normally the perched playa is dry (hence a "playa"), but this year it's filled from the heavy rains last winter.