Planetary scientists have identified thousands of Small Oceanic Ridges (SMRs) across the Moon’s maria, indicating active tectonic movements that could influence the next era of space exploration. These SMRs are geologically young, dating between 50 million and 310 million years, and are widely distributed across the lunar surface.
Small Mare ridge in northeast Mare Imbrium, captured by the Lunar Reconnaissance Orbiter Camera. Image credit: NASA/GSFC/Arizona State University.
Both the Moon and Earth experience active crustal movements, yet the tectonic forces shaping each celestial body differ significantly.
The Earth’s crust is segmented into plates that converge, diverge, and slide against one another, creating vast mountain ranges, deep ocean trenches, and a ring of volcanoes surrounding the Pacific Ocean.
Conversely, although the Moon’s crust isn’t divided into plates, internal stresses generate distinctive landforms.
Among these are foliated scarps, which arise when compressive forces push materials along faults, forming ridges. These cliffs, visible in the lunar highlands, have formed within the last billion years, representing the most recent 20% of the Moon’s geological timeline.
In 2010, researcher Tom Watters from the Smithsonian Institution discovered that the Moon is gradually shrinking, leading to the development of these foliated cliffs.
However, the creation of foliated scarps does not account for all the recent contractional topography observed on the Moon.
A newly identified category of tectonic landform is the SMR, caused by similar forces to those that form foliated cliffs. While foliated cliffs exist at high altitudes, SMRs are exclusive to the Moon’s maria.
In the latest study, Dr. Watters and his team aimed to map the SMRs in the lunar maria and assess their correlation with recent tectonic activity.
“Since the Apollo missions, we’ve known that foliation is prevalent throughout the lunar highlands, but this study marks the first documentation of similar features across the lunar maria,” stated Dr. Cole Nipaver, also affiliated with the Smithsonian Institution.
“This research will enhance our understanding of recent lunar tectonism, providing deeper insights into the Moon’s interior, its thermal and seismic history, and the potential for future lunar earthquakes.”
The researchers compiled the first comprehensive catalog of SMRs on the Moon’s far side, identifying 1,114 new SMR segments, bringing the total known SMRs to 2,634.
They discovered that the average age of these SMRs is 124 million years, aligning with the average age of foliation stumps at 105 million years.
These findings suggest that, akin to foliated scarps, SMRs are some of the Moon’s youngest geological features.
Additionally, our analysis indicates that SMRs form due to the same types of faults as foliated scarps, and that the highland foliated scarps often transition into SMRs, suggesting a shared geological origin.
The new SMR data, alongside the high-altitude foliation scarps, provide a comprehensive view of the Moon’s recent crustal contraction activities.
“Our identification of the Moon’s young SMRs and understanding their formation contributes to the global perspective of a dynamically contracting Moon,” said Watters.
For further details, view the result published in Planetary Science Journal.
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C.A. Nye Paver et al. 2025. A new global perspective on recent tectonism in the lunar maria. Planetary Science Journal 6, 302; doi: 10.3847/PSJ/ae226a
Source: www.sci.news
