A global investigation of wrinkle ridge formation events; Implications towards the thermal evolution of Mars

Wrinkle ridges (WR) are well-established paleo-stress indicators providing information on the compressional history and thermal evolution of Mars. Therefore, constraining their timing of formation on a global scale could yield better insight into the tectonic history, evolution of the mantle, and the paleoclimate of the planet. Here, we have updated the existing global map of the Martian WRs (up to a latitude of 70o on either hemisphere) using high-resolution Context (CTX) Camera images from twenty-seven different regions and inferred their ages using the Buffer Crater Counting (BCC) technique. The BCC technique enables us to conduct age estimation even when WRs propagated through more than one geological unit, or even the accountable compressional stress is younger than the underlying geologic unit, giving an additional advantage over the conventional relative age estimation technique. Globally, we have found that the ages of the WRs are almost entirely of the Early Hesperian (3.66–3.4 Ga) phenomenon, with exceptions from the Sinai Planum (~ 3.14 Ga; Late Hesperian) or dichotomy perpendicular ridges from the Amenthes Planum (~2.52 Ga; Amazonian) which possibly produced due to the horizontal forces that emerged due to isostatic adjustments. We have identified at least five distinct phases (~3.66, 3.62, 3.59, 3.48, and 3.14 Ga) of compressional deformations, related to the crustal growth in response to isostatic adjustments and flexural loading from the Noachian/Hesperian boundary period to the Late Hesperian period in and around the Tharsis region. In the eastern hemisphere, we have observed that the WR formation-stresses are global (peak global contraction ~3.59–3.55 Ga; responsible for the formation of WRs within southern highlands, parts of northern lowlands) to regional (around Syrtis Major and Malea Planum) in scale. Additionally, the estimated WR-ages indicate multiple phases of volcanic activity (~3.7, 3.54, and 3.40 Ga) eventuated at several provinces of the planet. Therefore, we conclude from the observation of WR-formation ages that the Martian mantle was vastly active during the Noachian/Hesperian boundary and the intensity of the mantle activity decreased through time, giving rise to multiple pulses of regional volcano-tectonic events, as a part of thermal evolution over the Hesperian period.