One Planetary Survey Robot that was sent by the Gliesians came into our solar system during the Amazonian period and surveyed Mars and Earth. The Amazonian period-started 3.3 Gyr ago. The Mars that the Planetary Surveyor examined noted that there were not many regions with meteorite impact craters, otherwise the terrain was quite varied. It looked like the right place to explore. If we go by the mineral time scale we would be in the Siderikan era (named for iron in Greek, for the iron oxides that formed) it began about the same time the Amazonian period began. At the beginning of this era there was a decline of volcanism and water was still plentiful, the most notable thing on the planet’s surface was the weathering process that caused the slow oxidation of the iron-rich rocks by atmospheric peroxides producing the red iron oxides that gave the planet its reddish color. But then it also looked more like a green and blue habitable planet.
A comparison: This tells you how little we know of this planet's history:
Crater Time Line:
Mineral Time Line:
The Earth time period equivalent to this time would be the late Archean era 3.8-3.5 billion years ago. Photosynthesis began at this time. At the end of the Achaean era around 2.5 billion years ago the Proterozoic era began. The atmosphere on Earth had not become oxygen rich yet there and there were other gases in the atmosphere that were not good for life as we know it. The first simple life appears, after that first multicultural life appeared. Then the Paleozoic is when the first vertebrae animals appears followed by the dinosaurs from the Melezoic to the Cenozoic periods It was a not a good time to migrate there so the Surveyor noted.
A Martian Plant and grass
As the Surveyor came to Mars it flew into the atmosphere and began its orbit. It began to analyze the gases in the atmosphere. Record pictures of the land below the land in the south and the ocean in the northern areas. There was also plant life and animal life on the planet much of it resembling prehistoric Earth.
Mars During the Early Amazonian and Siderikan Periods
The Mars that the Planetary Surveyor explored was not the Mars we see today. It would have been a green and blue planet with life on it. The enormous impact basins, like the Hellas Planitia in the southern hemisphere may not have existed yet. If it had it would have definitely been an inland sea.
A Prehistoric Martian Swamp
There would have probably been the ancient, low-relief volcanic construction at the Tharsis Bulge located along the northeastern and southwestern portions of the rim. There would also have been more volcanic activity than the Tharsis Bulge on the planet- maybe even on the other side of the planet. The basin floor contains thick, structurally complex sedimentary deposits that appeared to have a long geologic history of deposition, erosion, and internal deformation. The two other large impact structures on the planet are the Argyre and Isidis basins if they existed then, would have become lakes. The Argyre lake was located in the southern highlands and would have been surrounded by a ring of mountains and lush greenery.
The Valles Marineris at Night
Near the equator, what the Planetary Surveyor saw was not the Valles Marineris as we see today. There was to be sure a canyon there but one that was growing steadily bigger and bigger over time. There was also a river going down this rift valley. Since plate tectonics at the time was still working it would still be going through the process to be the huge long rift canyon we see today. It would have been surrounded by greenery and forests.
The Early Planum Boreum (the Martian North Pole)