Re:"recent"
Depends on what you mean by "recent"
First off, water and CO2 behave quite differently at the temperatures and pressures of Mars.
That said, every 26 million years or so large amounts of both will be released by very large impact events. Remember that this process has been going on for some 4.6 billion years (4.6 billion divided by 25 million equals), and that most volatiles released will be increasingly swept away by the solar wind, as Mars' core cooled and its protective magentic field failed.
Finally, remember that currently there is little to erase or modify any features formed in an earlier catastrophic outburst event.
EP