Multiringed basins - illustrated by Orientale and associated features.

TLDR

The study maps and photographs the Orientale multiring basin to investigate the origin, size, and distribution of its ejecta. Ejecta were transported by block gliding, landsliding, debris flow, and possibly base surge, viscous flow, and ballistic ejection. Six ejecta facies—concentric, radial, smooth plains, grooved, secondary impact craters, and fissured—were identified, with mainly clastic material but abundant melts and annealed breccias, and evidence of lateral and vertical zoning from mixing with substrate.

Abstract

Geologic mapping and photographs of the Orientale multiring basin are studied as to origin, size, and nature and distribution of ejecta. Six facies of ejecta are observed around the Cordillera Mountains: concentric, radial, smooth plains, grooved, secondary impact craters, and fissured. Transport of these ejecta occurred by block gliding, landsliding, debris flow, and possibly by base surge, viscous flow, and ballistic ejection. The ejecta are mainly clastic types, but melts and annealed breccias are expected to be abundant. Mixing of ejecta and substrate materials must have occurred; compositions of the ejecta are probably zoned laterally and vertically.