The lithosphere of the Moon has been deformed by tectonic processes for
at least 4 billion years, resulting in a variety of tectonic surface
features. Extensional large lunar graben formed during an early phase of
net thermal expansion before 3.6 Ga. With the emplacement of mare
basalts at ~3.9 – 4.0 Ga, faulting and folding of the
mare basalts initiated, and wrinkle ridges formed. Lunar wrinkle ridges
exclusively occur within the lunar maria and are thought to be the
result of superisostatic loading by dense mare basalts. Since 3.6 Ga,
the Moon is in a thermal state of net contraction, which led to the
global formation of small lobate thrust faults called lobate scarps.
Hence, lunar tectonism recorded changes in the global and regional
stress fields and is, therefore, an important archive for the thermal
evolution of the Moon. Here, we mapped tectonic features in the
non-mascon basin Mare Tranquillitatis and classified these features
according to their respective erosional states. This classification aims
to give new insights into the timing of lunar tectonism and the
associated stress fields. We found a wide time range of tectonic
activity, ranging from ancient to recent (3.8 Ga to < 50 Ma).
Early wrinkle ridge formation seems to be closely related to subsidence
and flexure. For the recent and ongoing growth of wrinkle ridges and
lobate scarps, global contraction with a combination of recession
stresses, diurnal tidal stresses, as well as with a combination of SPA
ejecta loading and true polar wander are likely.