Petrology of brecciated ferroan noritic anorthosite 67215.

A petrologic study of breccia 67215 is presented, showing that the rock has the bulk composition of a ferroan noritic anorthosite and is a polymict breccia containing several lithic clast types within a crushed, cataclastic matrix. The dominant lithic clasts contained in breccia 67215 are found to be igneous and metamorphic low- and high- Ca pyroxenes and olivine. Other clasts include granulated and sheared clasts, coarse-grained anorthosite with relatively Fe-rich augite, aphanitic, feldspathic microporphyritic melt breccias, and an impact-melt rock with strongly zoned relatively Mg-rich pyroxene. It is concluded that this rock type is relatively common in the highlands regolith excavated by the North Ray Crater.