Millions of years ago, the mountain ranges within Jasper were built by a process of sedimentation, compression and uplift: the brownish Main Ranges, which straddle the continental divide, were formed about 120 million years ago, largely of coarse sandstone, slate, limestone, shale and quartz. To the east, the grey Front Range, about 500 metres lower, rose up around 40 million years later. In spite of the glaciation and erosion over the last 2 million years - the Little Ice Age ended about 100 years ago - many of the mountains in the Main Range still average a spectacular 3350 metres with the highest, Mount Robson towering 3954 metres. During the last great ice age, 12 000 years ago, a river of ice filled the Athabasca Valley creating cirques, moraines and couloirs, then leaving behind eskers, kettles, lakes and winding rivers as it melted and moved up the valley. Post-glacial erosion accounts for deltas and canyons, Maligne Canyon being the most spectacular example of the cutting power of moving water. The creation of caves and the breakdown of rocks are usually the consequence of freezing; rockslides, avalanches, mudslides, dunes and hoodoos are the effects of gravity and wind. Rain, snow, wind and gravity working for hundreds of thousands of years have left ragged mountain peaks and broad V-shaped river valleys with wooded lower slopes and alpine tundra above the tree line. Glacial ice remains, for now, along the continental divide. The melt water from Mount Snowdome flows into three oceans and the 6.5 kilometre long Athabasca Glacier continues to melt and flow downward. Massive ice fields cover over 5% of the park, with 15 - 20 glaciers, as much as 300 metres thick, visible from the Icefield Parkway that runs from Lake Louise to Jasper.

Jaspers three ecological zones are home to 1300 species of plants: the dry forested montane in the river valleys that makes up 10% of the park, the sub-alpine forests and the rocky alpine tundra. The grassy open slopes and mixed wood forests of the montane zone make ideal grazing. Trembling aspen and Douglas fir grow primarily in the river bottoms where climate is less severe. Lodgepole pine benefit from the park's burning program that increases productivity by releasing seeds for germination and produces new growth for grazing animals. The montane is also home to Brown-eyed Susans and arnica, paintbrush, crocus, yellow lady's slipper, wild rose and wild strawberry. About half of Jasper is sub-alpine forest characterized by larch, sharp-pointed Engelmann spruce and alpine fir, which can spread down valleys like a black tide. Multi-coloured columbine and the orange western wood lily cling to the mountain slopes. Above the treeline, the back country alpine tundra display moss campion with small pink flowers growing in clusters, wolf lichen, old man's beard and dog-ear lichens that may have been growing there for a hundred years.