Brashear Crater is an impact crater in the Thaumasia quadrangle

Thaumasia quadrangle

The Thaumasia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program...

 of Mars, located at 54.14 S and 119.03 W. It is 77.45 km in diameter, and was named after John A. Brashear (1840–1920), an American astronomer. The name was approved in 1973.

Sand Dunes

Many places on Mars have sand dunes. Some craters in Thaumasia show dark blotches in them. High resolution photos show that the dark markings are dark sand dunes. Dark sand dunes probably contain the igneous rock basalt. Brashear Crater, pictured below, is one crater with dark dunes.