Recent progress in studying orbital forcing of late Amazonian climate changes on Mars from Polar Layered Deposits

Paleoclimatic history on Mars is an important aspect for understanding the evolution of Martian habitability. The polar layered deposits (PLD) can provide deep insight into paleoclimate changes over the last several million years. Since 1960s, researchers have studied almost all aspects of the properties for the PLD and tried to reveal the underlying climate periodic characteristics. Although much progress has been made in orbital periodicities borne in the PLD, it is not completely known that how the Martian orbital changes forced the formation of the PLD and what climate information is recorded in the PLD. Future studies should be carried out in the integrated research on the PLD via multi-profiles throughout the entire Martian polar regions to clarify their general features at the hemisphere scale and in the numerical model coupled with modern observation on dust and water vapor transportation. Furthermore, future landing missions may help to reveal definitely the paleoclimatic characteristics contained in the PLD by drilling into the layered deposits and even measuring mineralogical and geochemical compositions of the drilled samples.