Last year another Dawn team, using the spacecraft's infrared spectrometer, found infrared absorption bands due to carbonates in Cerealia Facula
. The carbonate deposit must be fairly thick, too, because the dome bears a dozen small impacts, 80 to 300 m across, and all are bright like their surroundings.
The region, called Sotra Facula
, includes a 1,000-meter-high peak and a 1,500-meter- deep pit, both shown in this false-color image (green highlights possible volcanic areas, blue marks sand dunes).