Deformation of Silicates from the Sea of Tranquillity

Abstract

Plagioclase and olivine crystals in the crystalline rocks from the Sea of Tranquillity show little or no evidence of either static or dynamic deformation. The large disorientations in many of the pyroxene crystals are commonly consistent with slip on the system T -(100), t = [001], but these distortions are not due to plastic flow. They are ascribed to rapid growth and quenching phenomena as deduced from studies of chondrules and of quenched natural and experimentally produced melts. Some of the silicates in the breccias and regolith show evidence of shock deformation, from mild to intense, as indicated by pervasive featuring, shock lamallae, and partial transformatiion of pyroxene and plagioclase crystals to glass.