Young mare volcanism in the Orientale region contemporary with the Procellarum KREEP Terrane (PKT) volcanism peak period ∼2 billion years ago

The crater retention ages of the mare deposits within the Orientale multi-ring impact basin are investigated using 10-m resolution images obtained by the SELENE (Kaguya) spacecraft, in order to constrain the volcanic history of the Moon around the nearside-farside boundary. Precise crater-counting analyses reveal that mare deposits in the Orientale region are much younger than previously estimated: similar to 2.9 Ga mare basalt in the eastern part of Mare Orientale and similar to 1.8-2.2 Ga mare deposits in Lacus Veris and Lacus Autumni, maria along the northeastern rings of the basin. The latter age estimates indicate that the Orientale region experienced volcanic activities similar to 2 billion years after the basin-formation impact. The dominance of a uniform surface age across the mare deposits in the peripheral regions strongly suggests that these volcanic eruptions are contemporary with the elevated volcanic activity episode proposed for the Procellarum KREEP Terrane on the lunar nearside at similar to 2 Ga and that this activity peak is much more widespread than previously estimated. The longevity of mare volcanism in the Orientale region further suggests high initial temperatures and/or high content of heat-producing elements in the underlying mantle of this region. Citation: Cho, Y., T. Morota, J. Haruyama, M. Yasui, N. Hirata, and S. Sugita (2012), Young mare volcanism in the Orientale region contemporary with the Procellarum KREEP Terrane (PKT) volcanism peak period similar to 2 billion years ago, Geophys. Res. Lett., 39, L11203, doi:10.1029/2012GL051838.