Recent and Active Surface
Changes on the Moon

High-resolution images from the Narrow Angle Camera (NAC) aboard the Lunar Reconnaissance Orbiter (LROC) have revealed geological and geomorphological features on the Moon in unprecedented detail, enabling the study of recent and active surface processes. Among the new discoveries are missing or degraded small craters, disturbed regolith from downslope creep, fresh boulder fields on scarps, and boulder falls — all interpreted as evidence of recent ground shaking from impact cratering and/or lunar seismic activity.

1. Slope Deformation Processes on the South Massif

Recent tectonism and the long-lasting effects of subsurface geometry in Taurus-Littrow Valley, Apollo 17 landing site

The South Massif and Taurus-Littrow Valley represent a unique setting for understanding recent geological processes on the Moon. Two overlapping landslide deposits and boulder falls indicate that repetitive instability has affected the north-east facing slope of the South Massif. The young Lee-Lincoln lobate scarp, associated with a thrust fault, suggests seismic shaking may have been an important trigger for surface changes and mass-wasting events in the area.

In this work, we use the younger landslide deposit — the Light Mantle — as a geomorphological marker. It is the only known extraterrestrial landslide with an absolute age constraint (70–110 Myr), provided by the Apollo 17 returned samples, making it a valuable time marker for surface changes that occurred since its emplacement.

We identify a variety of features on the NE slope of the South Massif that record recent slope deformation: boulder tracks, disturbed regolith, breaks in slope, crestal graben, and other linear slope structures. The pervasive nature of this deformation evidence suggests repetitive processes have effectively reshaped these slopes — driven by the ongoing effects of recent tectonism along the Lee-Lincoln fault, coupled with subsurface geometry inherited from the original impact basin formation.

For more details:
Magnarini et al. (2023) Slope Deformation Associated With Recent Tectonism and the Lasting Effect of Local Subsurface Geometry in the Taurus-Littrow Valley, Apollo 17 Landing Site. Journal of Geophysical Research: Planets 128, e2022JE007726.

Rose diagram and map of slope deformation features in Taurus-Littrow Valley

2. Tycho's Secondaries

Secondary craters as absolute stratigraphic markers

Work in progress — details coming soon.