The figure shows the titanium abundance measured by the Apollo Gamma-Ray Spectrometer. Red is a high abundance, yellow and green are intermediate abundances, and blue and purple are low abundances. Titanium on the Moon's surface occurs primarily in the mineral ilmenite.
Titanium is very rare in the lunar highlands and of variable abundance in the lunar maria.
High titanium abundances are found in Mare Serenitatis and Mare Tranquillitatis. Among the lunar samples returned to Earth, the highest titanium abundances were in fact observed in Apollo 11 and Apollo 17 samples from these maria, although some very low titanium basalts were also sampled by Apollo 17 . Another high titanium area is in western Oceanus Procellarum, a region that was not sampled by Apollo. The Gamma-ray Spectrometer data indicates that other mare regions have lower Ti abundances. Data is only available for portions of the Moon overflown by Apollo 15 and Apollo 16 .