Ignoring the Ice Warriors, Mars has a straightforward history. It had some form of life twelve million years ago, destroyed by the Fendahl after it escaped the fifth planet. Horus constructed the pyramid to control Sutekh's imprisonment around 5000 BC. In 1970, the Mars probe six met alien ambassadors there, although as the meeting was brief and in one location (Mars is a big planet), perhaps the Warriors were there during this period, possibly living underground. [Varga's statement that 'ice is our friend' hints that they inhabit the polar ice caps of their native world.]
By the late 40th century, the planet had been colonised by Earth (see The Daleks' Masterplan), although this could be in peaceful coexistence with the Martians, and in the far future the Usurian company terraformed the planet to provide a home for the population of Earth (see The Sun Makers). This would definitely have destroyed the Ice Warriors or forced them to move.
The Seeds of Death takes place in the 21st century (where Mars is again described as 'dying') and The Ice Warriors around 3000. The Peladon stories are set after this, during which time the Martians have made peace with mankind and joined the Federation.
Concerning Varga's original mission to Earth: In The Ice Warriors Arden speculates that Varga has been frozen in the permafrost since 'the first ice age', which is normally presumed to be a reference to the Pleistocene era, the first epoch of the Quaternary period (between 1.8 and 1.3 million years ago). However, estimates given as to how long the Warriors have been frozen do not tie in with this. The Doctor speaks of 'centuries' and Victoria of 'thousands of years'. In addition, the story takes place in an area previously inhabited by man.
This suggests that the Ice Warriors landed on Earth and were trapped in the glacier during the first stages of the present 'ice age', which Clent dates as having begun about a hundred years previously. (They burrowed down into the glacier: thus, mastodons are found at the same level.) If millions of years had elapsed, Miss Garrett wouldn't have been so worried about the possibility of nuclear material being released as it would have decayed.