Mare basalts from the Taurus-Littrow region of the moon.

Two distinct chemical basalt types have been sampled at the Apollo 17 landing site. Very high-titanium basalts (about 13 wt % TiO2) are the dominant type and display a textural range from olivine-porphyritic, ilmenite vitrophyres to plagioclase-poikilitic, ilmenite microgabbros. Most of these rocks could have come from one flow. These basalts appear to represent partial melts from feldspar-ilmenite cumulates with an Ar-40/Ar-39 age of about 3.7 G.y., which have experienced little, if any, near-surface fractionation of olivine and Fe-Mg-Ti oxides. A second type of basalt virtually identical to the Apollo 11 (low-K) basalts is much less common.